Amyotrophic lateral sclerosis (ALS) is a fatal, multigenic, multifactorial, and non-cell autonomous neurodegenerative disease characterized by upper and lower motor neuron loss. Several genetic mutations lead to ALS development and many emerging gene mutations have been discovered in recent years. Over the decades since 1990, several animal models have been generated to study ALS pathology including both vertebrates and invertebrates such as yeast, worms, flies, zebrafish, mice, rats, guinea pigs, dogs, and non-human primates. Although these models show different peculiarities, they are all useful and complementary to dissect the pathological mechanisms at the basis of motor neuron degeneration and ALS progression, thus contributing to the development of new promising therapeutics. In this review, we describe the up to date and available ALS genetic animal models, classified by the different genetic mutations and divided per species, pointing out their features in modeling, the onset and progression of the pathology, as well as their specific pathological hallmarks. Moreover, we highlight similarities, differences, advantages, and limitations, aimed at helping the researcher to select the most appropriate experimental animal model, when designing a preclinical ALS study. Amyotrophic lateral sclerosis (ALS), also known as Charcot’s or Lou Gehrig’s disease, is a multisystem neurodegenerative disease, characterized by heterogeneity at the genetic, neuropathological, and clinical levels . The proSeveral causes have been proposed as the basis of the disease onset and progression, such as excessive calcium and glutamate excitotoxicity ,12,13,14SOD1), chromosome 9 open reading frame 72 (C9orf72), fused in sarcoma (FUS), and TAR DNA-binding protein (TARDBP) [Most ALS cases are sporadic (sALS), and up to 10% have been classified as familial ALS (fALS) . Current(TARDBP) . Moreove(TARDBP) .In addition to genetic mutations, ALS may be also associated to environmental factors able to alter nerve cell functions .Mutations of the gene encoding for Cu/Zn SOD1 are among the most frequent ones in ALS . Since STARDBP gene, encoding the TAR DNA binding protein 43 (TDP-43), have been also identified in ALS [Mutations related the d in ALS . Mutatedd in ALS ,48,49, cd in ALS .FUS/TLS gene, encoding for the RNA-binding protein FUS [Other gene mutations involved in ALS are those related to the tein FUS ,52. Thistein FUS ,53, leadtein FUS .C9orf72 gene’s non-coding region has been identified in ALS and demonstrated to alter critical cellular processes, including autophagy, membrane trafficking, immune response [C9orf72 repeat expansion manifest ALS phenotype, while others only FTD or both. Moreover, there is no apparent correlation between repeat size and disease severity [More recently, the repeated expression of hexanucleotide “GGGGCC” (G4C2) in the response ,55,56,57severity . To dateseverity . The firAll the above gene mutations contribute to ALS development and progression by triggering different toxic processes , such asYet, there are other less frequent protein mutations involved in familial ALS form, such as: VAMP-associated protein B (VABP), Optineurin (OPTN), Valosin Containing Protein (VCP), Ubiquilin-2 (UBQLN2), Matrin 3 (MATR3), TANK-Binding Kinase-1 (TBK1), NIMA-related Kinase-1NEK1, and C21orf2 mutations ,70.Finally, it is important to consider also the interplay between environmental factors and genetic mutations that contributes to further complicate the multifactorial scenario of ALS ,71.Following the initial discovery of mutations in fALS patients, it was possible to model the human disease in living organisms to elucidate the mechanisms underlying MN death. Even though the obvious limitations of animal models, and possibly for this very reason, their number is still growing in the attempt to obtain further items to identify adequate targets for the development of effective therapies, which this very complex disease urgently needs ,73,74,75® online database by applying a systematic keyword cross-combination strategy, including genus/species coupled with ALS-linked genetic mutations.The purpose of this article is to provide a comprehensive and up-to-date overview of the available ALS animal models with the aim of offering details, including pros and cons, useful to design and optimize preclinical studies to investigate ALS. The present review is based on the collection of the most relevant articles present in the literature and focused on ALS animal models that have been identified on the PubMedIn the following chapters, we will examine a variety of experimental models of the disease, from the most used to the least common, based on the ALS genetic mutations and the different organisms in which they have been reproduced. In addition, we have also included some very interesting non-genetic models in which MNs injury is based on autoimmune mechanisms or on the exposure to possible ALS environmental risk factors.Indeed, genetic mouse models have been playing a major role in elucidating the known pathways involved in the etiopathogenesis of ALS and in identifying new promising leads to further progress into clinical phases. The number of mouse models is still growing in parallel with the identification of new mutations, providing scientists with a variety of pathogenetic backgrounds and, even if each of them may present some drawbacks, they are an invaluable tool to increase our knowledge of ALS .G93A). Although developed on a specific point mutation that accounts for by 15–20% of the familial cases [SOD1G93A mouse has been largely used for preclinical studies [After the discovery in the 1990s of the first ALS-linked gene mutation related to SOD1 , the firal cases , this moal cases . The SOD studies ,78,79 an studies ,81.This model clearly reproduces most of the pathological mechanisms of ALS in patients  and alsoSOD1G93A mouse model may spontaneously and progressively lose copy number of the mutation in the chromosome 21, which can directly impact the severity of the disease [Despite the clinical and mechanistic features that allow the researchers to study many aspects of the disease, a number of caveats has emerged that need to be considered for a correct use of this model in preclinical study design. The  disease , thus ac disease ,86. Of n disease . Moreove disease .SOD1 mutations in ALS patients, numerous other models have been developed, including the SOD1G37R, SOD1G86R, and SOD1G85R transgenic mice [According to the currently known variants of nic mice ,88,89. Anic mice .SOD1 rat models have also been developed, particularly with G93A and H46R mutations, showing genetic alteration-derived pathological features similar to those described in mice. They showed upper and lower MN degeneration and the disease severity was directly proportional to mutant SOD1 copy expression [Mutated pression ,91. In ppression . Rat modTARDBP) that accounts for approximately 4% of FALS patients and are also present in several apparent SALS cases [TARDBP mutations represent other important models to further investigate neurotoxic mechanisms in ALS.Other important mutations have been found in the gene encoding for TDP-43  or mutated TDP-43 may cause multiple RNA changes and nonspecific toxicity [At present, approximately 20 TDP-43 mouse models have been established since the discovery of these mutations in fALS . Althougtoxicity . Moreovetoxicity ,74.The first transgenic TDP-43 mouse models overexpressed wild type or mutant (A315T and M337V) TDP-43 cDNAS and were obtained by using a prion protein (Prnp) gene promoter ,96,97. TLater, Prnp promoter was further engineered to express wild type and other mutant TDP-43 cDNAs, resulting in a less aggressive phenotype . In partOn the contrary, in TDP-43-A315T transgenic mouse model, ubiquitinated TDP-43 cytoplasmic inclusions have been described . Of noteNew additional strategies have been developed in generating TDP-43 transgenic mice. One of these includes the incorporation of fragments from human genomic BAC containing libraries, taking advantage of the endogenous TDP-43 promoter to produce transgenic A315T, G348C, and wild type mice . These mAnother model expresses a form of TDP-43 that misses the nuclear localization signal (NLS) in a physiological fashion. This model was used in combination with calcium/calmodulin-dependent protein kinase II alpha promoter to drive doxycycline expression in neuronal cells, showing accumulation of cytosolic TDP-43 with minor aggregates, without developing an ALS phenotype . The subTARDBP gene were used to dissect the molecular effect of TDP-43 LoF or GoF in vivo in the absence of a transgene. In this context, the p.M323K mutation in the C-terminal low complexity glycine rich domain of TDP-43 caused splicing GoF associated to the development of late progressive neuromuscular phenotype with partial MN loss. On the contrary, the p.F210I mutation, leading to a LoF in the RNA binding activity of TDP-43, did not cause any pathological phenotype [Novel mouse lines with point mutations within the endogenous henotype .In general, we can assume that TDP-43 GoF in the cytoplasm is likely implicated in the mechanisms of ALS-associated TDP-43 mutations, but it should be also considered the clear heterogeneity of the phenotype that depend on the expression levels of the mutant protein and/or the genetic background of the animal model .Next to transgenic mice, both WT and M337V TDP-43 have been overexpressed also in rats . ExpressLike TDP-43, FUS is an RNA- and DNA-binding protein involved in ALS pathophysiology that plays a role in numerous cellular processes, including transcription, splicing, microRNA maturation, RNA transport, and stress granule formation . The preFUS mice showed high lethality paralleled by apoptotic MNs and cytosolic FUS mislocalization, whereas heterozygous ones presented increased cytoplasmic, but not nuclear, FUS level, and progressive MN loss (approx. 30% at 22 months of age) without proceeding to the end stage of the disease [Homozygous  disease .Other transgenic lines were produced, including the insertion of both the wildtype and multiple mutant FUS-containing cDNAs in the microtubule-associated protein tau (Mapt) gene locus. The models expressing this mutant form displayed NMJ deficits, MN loss, cytoplasmic FUS mislocalization, and aggregation, but no paralysis and death .FUSDelta14 heterozygous mice manifested progressive altered motor functions at 12 and 15 months of age, hind limb muscle denervation at 18 months, paralleled by MN loss, and reduced lifespan at 22 months. Moreover, this model showed increased FUS cytosolic localization with no apparent aggregates.A humanized knock-in model recapitulating a patient 3′splicing gene defect was developed a few years ago . These FFUSR521C mutation and showed severe motor deficit, cytosolic FUS inclusions, and premature death [Other transgenic mice with a more aggressive ALS phenotype originated from FUS overexpression using promoters such as Prnp or Thy1 genes. The use of Thy1 promoter to drive FUS cDNA with mutations in NLS guided to hemizygous mice with a rapid motor phenotype (2.5–4.5 months) leading to death a few days after the onset. These mice showed neuroinflammation and presented FUS inclusions in MNs and in other neuronal cells . Moreovere death . In thisFUS in rats induces motor axon degeneration with progressive paralysis, neuron loss in cortex and hippocampus, protein aggregation, and glial reactivity at early ages. Of note, transgenic rats overexpressing wild type human FUS were asymptomatic at the beginning of life, but they showed deficit in spatial learning and memory as well as significant loss of cortical and hippocampal neurons at advanced ages (12 months) [FUS seems to be more toxic than WT FUS.Transgenic rats have been also produced by intravenous administration of adeno-associated virus (AAV9) FUS. These rats showed progressive motor alteration and respiratory dysfunction . Overexp months) . As for SOD1 and RNA-binding protein mutations, genetic studies identified the location of the C9orf72 gene in the chromosome 9p21 locus in which mutations are linked to the GGGGCC repeated expansion (G4C2) [In addition to n (G4C2) ,124,125.n (G4C2) .Although all the functions of the C9orf72 protein are still a matter of investigation, several lines of evidence indicate a key role in the modulation of autophagy, endo-lysosomal trafficking, and immune response .C9orf72 gene mutation was developed in 2013 by Xu and collaborators [The first mouse model carrying a borators . These mborators . In addiborators ,130,131.C9orf72 knock-out mice have been created to evaluate the LoF effects [C9orf72-related ALS patients [C9orf72 KOMP mouse model, a significant decrease in survival was also observed, occurring at around 100 days of age [ effects ,134,135. effects . Knock o effects ,135 and patients . Moreoves of age . Finallys of age . In geneC9orf72 repeat expansion have been generated [C9orf72 ALS hallmarks, such as RNA foci in the nucleus and cytoplasmatic repeat-associated non-ATG (RAN) translation inclusions, even if differences in the expression level were observed [Later, four transgenic mouse models expressing the BAC human enerated ,139,140.observed . Interesobserved . A possiC9orf72 mouse models are useful as preclinical models for new therapeutic research both in-vitro and in-vivo [In conclusion, the  in-vivo ,141, butC9orf72 gene, using the CRISPR/cas9 technique, produced only some alterations to cervical lymph nodes and spleen, but no MN loss, thus supporting the notion that C9orf72 LoF alone is not responsible for ALS-like degeneration [C9orf72 KO rats were treated with low doses of kainic acid for four weeks, they developed significant MN death that was accompanied by progressive motor deficits, suggesting that C9orf72 LoF could trigger sensitization of MN to other risk factors, such as excitotoxicity, to induce ALS.With regards to rats, it has been reported that ablation of the neration . InteresC9orf72 knock-in rats were generated by knocking in 80 G4C2 repeats with human flanking fragments within exon1a and exon1b at the rat C9orf72 locus. These rat models reduced C9orf72 protein expression in several CNS areas and showed motor deficits from four months of age due to motor neuron loss, thus being a further useful model for investigating the contributions of loss-of-function to neurotoxicity in C9orf72-related ALS [Recently, ated ALS .ALS2 gene, localized to chromosome 2q33 [ALS2 gene mutations have been identified, but only four  were found in the RCC1 domain region expected to affect the protein, with the two mutations nearest to the amino-terminus (261delA and 553delA) resulting in frame shift mutations responsible for the development of juvenile ALS termed ALS type 2 (ALS2) [To date, two loci generating autosomal recessive forms of ALS have been linked to mutations in the ome 2q33 ,145. Thiome 2q33 ,145. Sev2 (ALS2) ,145,146.ALS2-deficient mouse models have been developed [As reviewed by Chandran et al. (2007)  and Cai eveloped ,151,152 eveloped ,151,153.SEXT gene is the cause of a juvenile form of ALS termed ALS type 4 (ALS4). In 2018, Craig and collaborators introduced the first mouse model carrying SEXT gene mutations and causing ALS4 [SEXT gene mutations (R2136H and L389S) via transgenesis and knock-in gene targeting, respectively. Both mouse models developed neuromuscular phenotypes and motor neuron degeneration, clearing of TDP-43 accompanied by TDP-43 cytosolic mislocalization that are consistent with the pathologic hallmarks of the human disease. Nuclear membrane abnormalities, related to nucleocytoplasmic transport proteins Ran and RanGAP1 in MNs, have been disclosed in SETX ALS4 mice and nuclear import was delayed in SETX ALS4 cortical neurons, indicative of impaired nucleocytoplasmic trafficking. Thus, SETX ALS4 mice recapitulate ALS disease phenotypes in association with TDP-43 mislocalization and provide insights for TDP-43 pathology, linking SETX dysfunction to common pathways of ALS MN degeneration.Senataxin (SEXT) is an RNA-binding protein with a highly conserved helicase domain, but it does not possess a low-complexity domain, making it unique among ALS-linked disease proteins. The mutation of the ing ALS4 . To dateOPTN gene mutations have been linked to the pathogenesis of both familial and sporadic ALS cases [OPTN gene point mutations have been identified as being causative of primary open-angle glaucoma in patients with ALS: a homozygous deletion of exon 5, a missense mutations R96L, a homozygous Q398X nonsense mutation, and a heterozygous E478G missense mutation [OPTN by the OPTND477N mutant, equivalent to the OPTND474N as non-disease-related human mutation of OPTN, and no motor phenotype alterations were registered [Optineurin (OPTN) is a protein mainly implicated in autophagy processes. LS cases ,156,157.mutation ,159. Morgistered .UBQLN2 gene mutations have been linked to ALS and FTD as reviewed by Renaud and collaborators in 2019 [UBQLN2 rodent models have been developed. Transgenic mouse models expressing hUBQLN2P497H manifested cognitive deficits, dendritic spinopathy, and UBQLN2 inclusions in the hippocampus, but neither TDP-43 pathology nor loss of motor neurons. Similarly, a rat model carrying the same mutation displayed cognitive deficits associated with UBQLN2 aggregates in hippocampus and evidence of neuronal death [UBQLN2P506T mice were also originated, showing cognitive impairment, but again, no motor deficits [UBQLN2P497S or hUBQLN2P506T mutations exhibited MN loss and cognitive impairments [Ubiquilin-2 (UBQLN2) plays a central role in the ubiquitin proteasome system (UPS) and its dysfunction results in protein aggregation . Several in 2019 , and manal death ,164. Knodeficits ; whereasairments .UBQLN2P497H and hTDP-43G348C mutations showed MN loss and muscle atrophy associated to motor and cognitive deficits during aging [Interestingly, a double transgenic mouse model harboring both hng aging .PFN1 gene and it is known to play an important role in cytoskeletal structure by regulating actin filament formation, driving cell motility and other actin-linked processes [PFN1 gene mutations are linked to ALS  [PFN1 gene mutations accelerated the protein turnover in cells [Profilin 1 (PNF1) is a protein encoded by the rocesses ,169. Sev, G118V) ,171, butin cells , alteredin cells , increasin cells .PFN1G118V transgenic mice exhibited many pathological features of ALS, including loss of lower and upper MNs, loss of MNJs, aggregation of the mutant profilin 1 protein, abnormally ubiquitinated proteins, increase in nuclear staining of phosphorylated TDP-43 in the spinal cord, fragmented mitochondria, glial cell activation, muscle atrophy, weight loss, and reduced survival [Hemizygous survival . Motor dPFN1C71G mutation has been induced in mice showing a progressing phenotype [PFN1 transgenic line in hemizygous state with a Thy1-PFN1C71G homozygous line, obtaining an accelerated ALS pathology [PNF1C71G under the control of the Hb9 promoter, targeting the mutation to α-MNs in the spinal cord during development. Adult mice presented significant motor deficits and a strong reduction in the number of MNs in the spinal cord, thus supporting the effect of profilin 1 during neurodevelopment.Expression of henotype . The hemathology . Recentlathology  developeVCP gene to obtain murine VCP-related disease models [R155H mouse model exhibited pathological characteristics of the human disease in muscles, bones, and brain, including age-dependent degeneration of ventral horn MNs, TDP-43-positive cytosolic inclusions, mitochondrial abnormalities, and progressive astrogliosis. Although these animals do not develop rapidly a progressive and fatal ALS-like pathology, they do recapitulate some key pathological features of the disease [VCPR155H mouse showed muscle, bone, and brain alterations like those of the heterozygous model, but at a very early stage, and mice usually survive less than one month [Valosin containing protein (VCP) is a protein involved in ER biogenesis and maintenance, whose gene mutations have been linked to several neurological disorders, including ALS ,179,180.e models ,182. The disease ,184. Thene month .VAPB gene have been observed in patients with ALS, such as P56S, T46I, del160, D130E, A145V, S160Δ, and V234I [VAPBP56S showed motor behavior defects [VAPB mice with the P56S mutation. These mice exhibited late-onset motor behavior defects, characteristic of patients carrying this mutation, and displayed many cellular pathological features implicated in ALS  before motor behavior defects.VAMP-associated protein B (VAPB) belongs to the VAMP-associated proteins that play important functions in membrane trafficking , neurotrnd V234I ,192,193.nd V234I ,195,196, defects  derived The first non-genetic model of ALS has been created in guinea pigs by using an ascorbic acid deficient diet inducing MN degeneration, muscle atrophy, and demyelination of the pyramidal tracts . In mostBesides genetic alterations, also environmental factors are known to play a role in ALS development ,203 and,In a first study, 21-day-old rats were i.p. injected with different doses of L-BMAA (up to 350 mg/kg/die) for five days and then analyzed for up to eight months with a set of neurological and functional tests ,205. At G93A mutant rats; however, no behavioral analysis was reported.A second model was developed by intrathecal infusion of L-BMAA (5 mM) to adult rats for 30 days via catheter-connected mini-osmotic pumps . This chFinally, also i.v. infusion of L-BMAA (300 mg/kg) for three consecutive days in adult rats resulted in a model that resembled many traits of ALS . Indeed,Although the L-BMAA model also shows features of other neurodegenerative diseases, it may represent a fruitful additional tool for ALS-related mechanistic and therapeutic studies.Drosophila melanogaster is an animal model very useful to study neurodegenerative disease, including ALS [Drosophila melanogaster a powerful genetic model is the UAS/Gal4 system [Drosophila melanogaster and disease-associated human genes. Like zebrafish, about 77% of the human ALS-associated genes have fly orthologs [Drosophila melanogaster [, Drosophila is considered a suitable and alternative model for studying genetic issues in many neurodegenerative disorders, including ALS [ding ALS ,209, sinding ALS ,211. Ano4 system , which irthologs . To datenogaster ,215. On ding ALS ,219,220.Drosophila melanogaster SOD1 enzymatic activity by deletions or missense mutations of the enzyme led to several pathological phenotypes. In the fly model of SOD1 LoF, lifespan was drastically reduced by 85–90% and locomotor activity was also impaired. In addition, the resistance to oxidative stress conditions was lowered and fertility and wing morphology were abnormal [SOD1A4V, SOD1G37R, SOD1G93C, SOD1G41D, SOD1I113T) resulted in a partial rescue, only. The lifespan reduction was paralleled by an early drop of negative geotaxis performance in line with the pathological phenotypes [Several studies have shown that inactivating the abnormal ,222,223.enotypes .SOD1 transgenes directly in MNs. The UAS/Gal4-driven expression of either WT or ALS-related SOD1 forms (A4V or G85R) in MNs did not alter lifespan in flies [SOD1 mutations at the conserved residues in fly SOD1, thereby creating fly SOD1G85R, SOD1H71Y, and SOD1H48R mutants [SOD1 mutations may display different pathological features depending on the specific mutated gene, spanning motor deficits, focal accumulation of SOD1 in MNs, glial cell enlargement [Drosophila melanogaster could help to understand the mode of propagation of misfolded SOD1, as well as the physiopathological relationships between MNs, glial cells, and muscles.Fly models were also generated using the UAS/Gal4 system  to overein flies , but indin flies ,226, a n mutants . In homo mutants . In geneargement , locomotargement , and mitargement . On thisTBPH) is the fly ortholog of TARDBP gene and LoF and GoF approaches have been modeled in fly to unravel TDP-43 functions.Since TDP-43 is highly conserved during evolution , it makeTBPH-null mutant flies, mortality was observed at the second instar larval stage [TBPH gene mutants displayed eclosion, climbing, and crawling defects, decreased or increased synaptic bouton number, reduced dendritic branching, impaired synaptic transmission, and axonal transport dysfunctions [TBPH were very toxic, causing premature mortality [In al stage , at the al stage , or durial stage ,235,236.unctions ,238,239.ortality , reducedortality ,242, larortality ,244.Drosophila melanogaster was also used to assess the effects of several human TDP-43 mutations. In this respect, both TDP-43G294A or TDP-43M337V homozygous flies had normal development and lifespan, the larval locomotion was unaltered, and their climbing capacity was only slightly reduced in respect to age-matched controls [TBPH insertion. Moreover, overexpression of mutant TBPH  was reported to induce aberrant eye morphology, axonal aggregates, crawling defect, eclosion defect, decreased bouton numbers, and decreased or no change in dendritic branching at NMJs [controls ,246. On controls ,249,250.controls ,239,247. at NMJs ,247.caz) is the only ortholog gene of FUS in Drosophila melanogaster [FUS have been also investigated. The overexpression of human FUS mutants led to several phenotypic alterations, including aberrant eye morphology , eclosion defect , climbing and crawling defects , reduced synaptic bouton number  or no change , and decreased active zone at NMJs  [The cabeza  ,259,260,FUS mutants [As in the case of TDP-43, the overexpression of WT human FUS induced a phenotype characterized by alterations that were almost completely superimposable to those observed with the different  mutants ,259,261.Drosophila melanogaster does not have a C9orf72 ortholog gene [C9orf72-associated ALS have been developed by overexpressing G4C2 repeat RNA, modelling DPR protein toxicity, thus revealing important molecular insights [C9orf72 mutations.log gene , thus mainsights . Transgeinsights ,266,267.insights ,269. Sevinsights ,271,272.insights . Moreoveinsights  have demDanio rerio) is often used to study embryonic development because of the transparency of their embryos and their vertebrate body plan [Zebrafish  and dominant (R521G) FUS mutants. Furthermore, the ALS-linked FUS mutants, but not the WT protein, assembled into perinuclear SGs in response to oxidative stress or heat shock conditions [FUS, mutant FUS mislocalized from the nucleus to the cytosol in cells other than MNs. Both WT and FUSR521C localized at SGs, demonstrating an intrinsic propensity of human FUS to aggregate, independently of disease-associated mutations or specific cell type. However, elevation of the relative cytosolic to nuclear FUS induced by the R521C mutation led to a significant increase of SG assembly and persistence within vulnerable cells, although these cells were not always motor neurons [FUS mutations also induced protein aggregation in MNs and other cells, oxidative stress, NMJ damage, and motor dysfunction [FUS orthologue in zebrafish led to homozygous mutants that displayed reduced lifespan and impaired motor abilities, associated with specific cellular deficits like decreased MN length and NMJ fragmentation. In addition, FUS LoF alters Tau transcripts, thus favoring the expression of small Tau isoforms [In the zebrafish model, both LoF and GoF of FUS function result in defective presynaptic function at the NMJ . Expressnditions . Moreove neurons . FUS mutfunction ,298,299.C9orf72 sequence translated into altered neuronal development, MN axonopathy and axonal degeneration, disturbed arborization and shortened axons at early developmental stages, cytoplasmic aggregation of TDP-43, and abnormalities in spontaneous and evoked swimming. These deficits were rescued by expressing the human WT C9orf72 mRNA, highlighting the specificity of the induced phenotype [C9orf72 transgenic zebrafish model, characterized by an accumulation of RNA foci and DPRs in muscle and in the central nervous system, showed motor defects and marked reduction of survival [Both LoF and a GoF of C9orf72 have been investigated in the zebrafish model . Deletiohenotype . These dhenotype ,302, thuhenotype , reducedhenotype . A recensurvival . AdditioC9orf72 patients, zebrafish transgenic models have been obtained [C9orf72 mutations. Additionally, the GA80-GFP model showed pericardial edema, reduced red blood cells, and muscle specific aggregates of GA80-GFP, but no significant differences in axon length and vascular pattern defects. Based on DPR toxicity, a stable transgenic zebrafish model expressing arginine-containing DPRs (poly-GR) has been developed [To reproduce the higher levels of DPRs observed in the CNS of obtained ,306. Linobtained , were geeveloped . In detaCaenorhabditis elegans (C. elegans) is another widely used ALS animal model [C. elegans makes the use of co-expressed fluorescent proteins useful to easily visualize neurons and monitor disease progression over time. Moreover, the well-defined and genetically manipulable nervous system of C. elegans provides an effective model to explore the pathological mechanisms of neurodegenerative diseases and a good tool for the screening of new potential drugs [C. elegans also shares many conserved molecular pathways and cellular mechanisms with mammals, thus representing a reliable experimental model [The nematode al model ,309. Traal drugs ,311. C. al model ,313.C. elegans models, neuronal expression of human SOD1G85R, but not WT SOD1 caused locomotor defects, cytosolic aggregates, axonal abnormalities, such as reduction in the number and diameter of cellular processes, and reduced numbers of organelles, both mitochondria and vesicles [C. elegans expressing human SOD1H46R or SOD1H48Q also displayed locomotor defects, although to a lesser extent than SOD1G85R [SOD1G93A specifically in MNs led to age-dependent paralysis because of axonal defects [SOD1 manifested differential toxicity toward glutamatergic and cholinergic neurons [In vesicles . NeverthSOD1G85R . Overexp defects . Additio neurons . In partSOD1, carrying the G85R, G93A, or G127X mutation in C. elegans muscles, formed different SOD1 aggregates according to the variant type, causing only mild cell dysfunction and reduced motility [Interestingly, the specific overexpression of human motility .C. elegans neurons have also been studied. Pan-neuronal expression of human wild-type TDP-43 in transgenic worms caused slowed and uncoordinated movements, as well as defasciculation of MNs [TARDBP, named TDP-1, has been identified in the nuclei of neurons and in the body wall muscle cells [TDP-1 gene deletion did not manifest development alterations or significant movement impairment, and showed normal GABAergic synapses [TDP-43 and TDP-1 during evolution.Phenotypic consequences of TDP-43 expression within n of MNs . On the n of MNs . In thisle cells ,321. Intsynapses . This isIt has been demonstrated that FUS variant expression, which induced protein aggregation specifically in GABAergic neurons, resulted in neurodegeneration, synaptic dysfunctions, and paralysis, whereas expression of wild-type FUS did not cause significant alterations .FUS genes with increasing degree of clinical severity in ALS patients as to onset age and disease duration (P525L > R522G) resulted in proportional FUS cytoplasmic aggregation and impaired motor functions that progressed with age, associated to decreased lifespan. Conversely, animals expressing two FUS mutations associated with rather mild forms of human ALS  did not show protein aggregation and manifested no obvious dysfunctions compared with WT-FUS controls, suggesting that mutations give FUS a neurotoxic GoF [Moreover, the pan-neuronal expression of two mutant oxic GoF .C9orf72 ortholog alfa-1 resulted in altered nuclear transport, MN degeneration, and severe paralysis in early adulthood [alfa-1 deletion also caused the formation of worms with defects in lysosomal homeostasis, including dysfunctions in lysosomal reformation and the degradation of endocytosed elements, which were partially rescued by the expression of human WT C9orf72 [C. elegans overexpressing 29 G4C2 repeats under the broadly active hsp-16 promoter displayed a more severe phenotype, including paralysis and death, compared to C. elegans overexpressing nine repeats only [Both C9otf72 LoF and GoF have been investigated in C. elegans models. The deletion of the dulthood ,325. In ats only .Saccharomyces cerevisiae can be used to study molecular pathways under both physiological and pathological conditions since approximately 6000 human genes [It is well known that key cellular processes are conserved throughout yeast, higher eukaryotes, and humans and, indeed, yeasts like an genes  and 500 an genes . In genean genes . To datean genes . In the an genes ,332,333.Saccharomyces cerevisiae carrying human WT or ALS-linked mutated genes for proteins such as SOD1, TDP-43, and FUS .SOD1 human genes in Saccharomyces cerevisiae lacking the ortholog gene [2), and showed resistance to paraquat-induced oxidative stress. This study pointed out that many SOD1 mutants displayed normal dismutasic activity, as supported also by studies on transgenic mice overexpressing human SOD1 mutants [SOD1 gene [One of the first attempts to model ALS in yeast was carried out by expressing WT or mutant  log gene . However mutants ,334,335. mutants ,337. To OD1 gene . The obtTARDP orthologous genes. However, there are useful methods and approaches to gain insight into TDP-43 biology and its role in disease by using yeast [Unfortunately, yeast do not seem to possess ng yeast .Dbr1 gene coding for debranching enzyme in TDP-43 yeast model, strongly suppressed TDP-43-induced toxicity, impeding its interference with cellular RNAs and RNA-binding proteins [CNC1 (Cyclin C), DNM1 (Dynamin-related), or YBH3 (Bax inhibitor) genes, all involved in the oxidative stress-induced mitochondrial fragmentation, significantly reduced TDP-43-induced cell death in yeast [The first yeast model with human WT TDP-43 overexpression showed that the protein accumulated in the cytoplasm and formed subcellular aggregates, which were found responsible for cell growth inhibition, deranged morphology, and cytotoxicity, thus recapitulating most of the features reported in cell culture models . Interesproteins ,342. Verin yeast .FUS ortholog and, therefore, models have been induced by ectopically expressing human WT and/or mutated FUS genes in yeast [As for TDP-43, yeast do not encode an in yeast ,345,346.in yeast  and inhiin yeast .Removing the RNA recognition motif of FUS does not act on aggregates production but rescues FUS-induced toxicity, thus highlighting that the interaction between FUS and RNA is essential for FUS toxicity . ConsistAlthough mouse is still the most used model to investigate ALS and other neurodegenerative diseases, there are other mammals that have been used for translational studies on this dramatic disease. However, their use is more limited for logistic, economic, and ethical reasons.Canine degenerative myelopathy (CDM) has been recognized as a spontaneous pathology occurring in specific dog strain, characterized by an adult-onset neurodegenerative spinal cord disorder and progressive impairment of motor functions ,351. CDMSwine models have acquired an emerging role due to their anatomical, physiological, and biochemical features closely related to the human ones, including genoma , model sSOD1-expressing swine model of ALS. Tg SOD1 swine showed hind limb motor defects, which are germline transmissible, MN degeneration, in a mutated SOD1 copies expression and age-dependent manner, gliosis and protein aggregates [SOD1 does not form cytoplasmic inclusions, whereas nuclear accumulation and ubiquitinated nuclear aggregates are present, like in some ALS patient brains [Chieppa and colleagues  producedgregates ,371. Thet brains .Later, Wang and colleagues  generateNotably, the utilization of large animal models like swine is useful in efficacy and/or safety studies of developing drugs as well as in gene silencing approaches using virally delivered shRNA, before their application in humans ,373.Non-human primates (NHPs) are the animal models closest to humans with regards to genetics, physiology, and behavior. Therefore, they play a critical role in several biomedical and translational research projects, being the best species to model many human diseases , includiMacaca fascicularis was created by injecting an AAV-based human WT TDP-43 coding sequence into the C5-6 spinal cord segment, ipsilaterally to the dominant hand [A TDP-43-overexpressing ant hand . After tSOD1 in spinal cord MNs. Recently, non-human primates have been used to test the potency, tolerability, and safety of single subpial AAV9 injection, demonstrating that AAV9 homogeneously distributes throughout the white and gray matter of cervical spinal cord and brain motor centers. This approach could be effective for subpial delivery of AAV9–shRNA–SOD1 to ameliorate clinical symptoms of ALS [Besides their use to model ALS, monkeys represent also an unvaluable model to study safety and feasibility of novel therapeutic approaches before clinical experimentation. As a matter of fact, two studies have been carried out to test the safety and tolerability of the anti-SOD1 therapy in non-human primate. In the first case, was applied a silencing method based on an artificial microRNA (miR-SOD1), systemically delivered in the marmoset, by lumbar intrathecal administration of a recombinant adeno-associated virus . Using s of ALS .MATR3 [CHCHD10 [TBK1 [TUBA4A [NEK1 [ANXA11 [C21orf2 [CCNF [Since 2014, new genes have been associated to ALS: MATR3 , CHCHD10[CHCHD10 , TBK1 [310 [TBK1 ,383, TUB [TUBA4A , NEK1 [34A [NEK1 ,386, ANX [ANXA11 , C21orf2[C21orf2 , and CCNf2 [CCNF . Some ofMATR3 was generated and developed either hindlimb paralysis or hindlimb and forelimb muscle atrophy [MATR3F115C mouse, showing myopathic changes that progressed from small vacuoles to large vacuolated fibers, rounded fibers, and fibers with internalized nuclei. Moreover, the MATR3F115C mice developed muscle weakness with variable onset. Recently, a transgenic mouse that overexpresses mutant MATR3S85C have been produced [MATR3 caused myotoxicity. Very recently, a MATR3S85C germline knock-in mouse was also generated [Drosophila results in shortened lifespan and motor deficits, with disease-associated mutants exhibiting increased toxicity over MATR3(WT) [MATR3 expression were accentuated by the S85C pathogenic mutations.Matrin 3 (MATR3) is a highly conserved RNA binding protein . Three m atrophy . Later,  atrophy , generatproduced . Overexpenerated . Two indATR3(WT) ,397. PheCHCHD10) have been identified in families with ALS or ALS-FTD [CHCHD10 KO animals exhibited a slight pathological phenotype, with no bioenergetic defects or ultrastructural mitochondrial abnormalities in the brain, heart, or skeletal muscle [S59LCHCHD10 mice displayed NMJ and MN degeneration, with fragmentation of the motor end plate and moderate motor neuron loss in lumbar spinal cord at the end stage of the disease, TDP-43 cytoplasmic aggregates in spinal neurons, and Mitochondrial Oxidative Phosphorylation System (OXPHOS) deficiency in muscle. CHCHD19S55L knock-in mice were developed by two other independent groups [CHCHD10R15L, which showed transgene copy-linked abbreviated lifespan compared with mice over expressing WT CHCHD10. However, CHCHD10R15L mice performed comparably to control mice in motor behavioral tasks, without developing paralysis.Several mutations in the gene encoding the Coiled-Coil-Helix-Coiled-Coil-Helix Domain Containing 10 protein  mutations have been associated to ALS ,383,403. humans. . In conte organs . Furthers of age . Very reenerated . DeletioCCNF model was developed in zebrafish, based on an ALS-linked missense mutation [Mutations of cyclin F (CCNF) have been also recently correlated to ALS cases . The firmutation . This moTUBA4A gene and protein expression dramatically increases with aging [SOD1 and C9orf72 [TUBA4A (R320C and A383T) showed altered neurite length and microtubule defects after exposure to selenium [Variants of the Tubulin Alpha 4A protein (TUBA4A) have been associated to ALS, with destabilization of the microtubule network and diminished repolymerization capability ,411. TUBth aging ,412, whi C9orf72 . No animselenium .NEK1 variants or the expression of R261HNEK1 and FALS risk has been identified [NEK1 gene are not available.A significant association between the deletion of entified ,386. To ANXA11) gene has been correlated to ALS, even if they are rare [ANXA11 gene are not available.Mutations in the Annexin A11 (are rare ,415. To C21orf2 have been recently related to ALS [Mutations in d to ALS . Bioinfod to ALS . To dateAlthough more than 50 disease-modifying drugs with different mechanisms of action have been studied in the last decades, only two have been approved for ALS patients, namely riluzole and edaravone that, however, have only very modest effects on the course of the disease ,418. ThuFollowing the continuous identification of mutated genes, many animal models have been developed to unravel the pathological mechanisms that are crucial to MN degeneration. Indeed, the cellular alterations in ALS are likely the result of many different interacting mechanisms leading to a larger network disruption. This has been clearly exemplified in experimental models where multiple factors support neuronal damage . The relModeling ALS as human neurodegenerative disorder into any other species, especially in mammals, is certainly a hard task in terms of face, construct, and predictive validity , and ALSFace validity regards whether the model recapitulates the main features of the pathology and its progression from both the clinical and anatomo-pathology point of view. Construct validity refers to what extent the cause of the experimentally-induced pathology reflects what causes the disease in patients. Finally, predictive value is the measure of the translational potential of the model, that is to what extent it predicts outcomes in patients, especially in terms of evaluation of therapeutic treatments.There are no doubts that the models here summarized have been playing a key role in unravelling the myriad of cellular and molecular determinants that are involved in ALS and its progression, and in showing the multifactorial and non-cell autonomous nature of this disease. With regards to mammal models, especially rodents, it is evident that none fully recapitulate the characteristics of the human disease, but they reproduce most of the salient neuropathological and clinical features that are observed in ALS. Moreover, these models are all based on pathology-inducing genetic mutations, thus obviously having higher construct validity for familial than for sporadic ALS, but it is worth recalling that the two forms show common pathological mechanisms, share most neuropathological/clinical hallmarks, and up to 10% of sALS cases include fALS-associated gene mutations . As for Similarly to human studies, accurate preclinical guidelines for phase-based efficacy evaluation of innovative therapeutic approaches and more transparency in reporting the experiments involving animals ,423 woulIn this review, we provide an overview of the different experimental models, from yeast to non-human primates, to investigate ALS pathophysiology. We clustered these models on a genetic mutation criterion, highlighting the peculiarities and the ALS-related molecular, cellular, and clinical symptoms, also focusing on pros and cons that need to be considered when approaching the study of ALS pathogenesis or new experimental therapies . Clearly


Ovarian cancers (OCs) are the most lethal form of gynecological tumors. The commonest are high-grade serous OCs, while rare OCs originate from many different cell types, such as epithelial, germ cell, sex cord-stromal, or mixed types. Rare OCs have distinct molecular characteristics, prognosis, and therapeutic approaches. However, all ovarian malignancies mostly share the same problem: late diagnosis due to the lack of specific symptoms. Therefore, there is a perpetual need to discover better diagnostic, prognostic, and predictive biomarkers, as well as new therapeutic approaches. In recent years, long non-coding RNAs (lncRNAs) have gained widespread attention because of their important role in various biological pathways. They have multiple mechanisms of action with an important role in many cellular processes related to OCs development and progression. This review will focus on the different aspects of lncRNAs in OCs and attempt to highlight the distinctive role of lncRNAs in common and rare OCs.Rare ovarian cancers (ROCs) are OCs with an annual incidence of fewer than 6 cases per 100,000 women. They affect women of all ages, but due to their low incidence and the potential clinical inexperience in management, there can be a delay in diagnosis, leading to a poor prognosis. The underlying causes for these tumors are varied, but generally, the tumors arise due to alterations in gene/protein expression in cellular processes that regulate normal proliferation and its checkpoints. Dysregulation of the cellular processes that lead to cancer includes gene mutations, epimutations, non-coding RNA (ncRNA) regulation, posttranscriptional and posttranslational modifications. Long non-coding RNA (lncRNA) are defined as transcribed RNA molecules, more than 200 nucleotides in length which are not translated into proteins. They regulate gene expression through several mechanisms and therefore add another level of complexity to the regulatory mechanisms affecting tumor development. Since few studies have been performed on ROCs, in this review we summarize the mechanisms of action of lncRNA in OC, with an emphasis on ROCs. Gynecologic malignancies comprise about 19% of all cancers diagnosed in women, and out of these more than 50% are classified as rare . They moGenerally, a major drawback in the research on ROCs is the lack of studies that separate the OC subtypes, as in most cases the samples are just classified as OC. Most studies examine OC in general or focus on the most prevalent HGSOC subtype. Even LGSOC is not well characterized within these studies, which makes analyzing available data difficult, and possibly misleading. Therefore, this review will outline the lncRNAs associated with OC in general, with the OC subtype defined where available, focusing on ROCs when possible.OC is a major cause of morbidity and mortality in women, with minimal improvement in survival rates over the past decades . OC is dTP53 tumor suppressor gene [BRCA1 or BRCA2, or hypermethylation of BRCA1 promoter with a loss of expression. The underlying loss of BRCA1/2 function and inability to repair double-strand repair breaks, which in turn leads to chromosomal instability, lead to a potential role for drugs targeting the DNA repair  [HGSOCs are chromosomally unstable tumors that commonly have mutations in the sor gene . In mostibitors) . The PI3ibitors) .CTNNB1, CDKN2A, PIK3CA, KRAS, ARID1A, PTEN, and PPP2R1A [Endometrioid carcinomas (EC) are the second commonest malignant ovarian neoplasm, accounting for 8–15% of all ovarian carcinomas. There is a strong association with endometriosis. Most EC is grade 1 or 2. Since at presentation they are predominantly low stage and low grade, the burden of morbidity and mortality associated with this subtype is relatively low, despite being common. The 5-year overall survival rates are 87.1%, 83.9%, and 44.7% for stage IA/IB, IC/II, and III/IV EC, respectively . There a PPP2R1A . Moreove PPP2R1A .BRAF, KRAS, NRAS, and ERBB2, but occasionally there may be driver mutations of FFAR1, PIK3CA, USP9X, and EIF1AX linked to the AKT-mTOR pathway [LGSOC represent <5% of all ovarian serous carcinomas, affecting younger women with a median age of under 55 years. The 5-year overall survival rates are 93.2%, 82.7%, and 54.2% for stage IA/IB, IC/II, and III/IV LGSOC, respectively . Despite pathway . MoreoveARID1A, activation of PIK3CA, and mutations in PPP2R1A and KRAS [ARID1A mutated OCCC include the inhibition of the methyltransferase EZH2 and the administration of dasatinib and/or the HDAC6 inhibitor ACY1215. Since EGFR expression is detected in up to 60% of OCCC cases, EGFR inhibitors may also be effective. In addition, mTOR inhibitors may also be promising due to the high expression of mTOR in both early- and advanced-stage OCCC [Ovarian clear cell carcinoma (OCCC) accounts for approximately 5% of all ovarian carcinomas. When diagnosed at an earlier stage, it tends to have a good prognosis as surgery is often curative. In advanced stages, however, it is associated with a poor prognosis as it is often chemoresistant . The 5-yand KRAS . Novel tage OCCC .KRAS, as well as mutations in CTNNB1 or APC gene, and high microsatellite instability (MSI-H) [Mucinous epithelial ovarian cancer (MOC) accounts for less than 5% of EOCs. The 5-year overall survival rates are 82.9%, 69.,5%, and 13.9% for stage IA/IB, IC/II, and III/IV OCCC, respectively . While i (MSI-H) .FOXL2 c.402C > G (p.C134W) mutation is helpful in the diagnosis of adult-type tumors [DICER1 mutations seem to be a prognostic factor that is associated with a higher risk of relapse, especially in younger patients. In these tumors, adjuvant chemotherapy is recommended in stage IA disease particularly if there is poor differentiation or heterologous elements. BEP is commonly used, or else etoposide/cisplatin, carboplatin, and paclitaxel, cyclophosphamide/doxorubicin/cisplatin, or platinum agents alone. The 5-year overall survival rates are 90.7% and 76.2% for granulosa cell tumors and Sertoli-Leydig cell tumors, respectively [Sex-cord stromal tumors and malignant germ-cell tumors are very rare non-epithelial ovarian tumors, which overall account for only 6% of all ovarian malignancies ,37,38,39e tumors . Howevere tumors . Granuloe tumors . For Serectively .KIT and KRAS, akin to testicular germ cell tumors [Germ-cell tumors can be histologically classified as dysgerminoma, immature teratoma, yolk sac tumor, choriocarcinoma, embryonal carcinoma, mixed germ-cell tumor, malignant struma ovarii, gonadoblastoma, and teratoma with malignant transformation . They arl tumors . Platinul tumors . Adjuvanl tumors . Furtherl tumors .In contrast to almost all other common OCs, the treatment of ROCs is challenging and often must be based on expert opinion, retrospective studies, or extrapolation from other tumor sites with similar histology. This leads to difficulty in developing effective guidelines for clinical practice.TP53, followed by ARID1A, PIK3CA, SMAD4, KRAS, APC, CREBBP, and PPP2R1A. Frequent deletions include CDKN2A, CDKN2B, ERBB4, NF1, NF2, CDC73, EZH2 and STK11 [TP53, followed by NF1, BRCA1, BRCA2, RB1, and CDK12 [CCNE1, MYC, and MECOM genes, and deletions of PTEN, RB1, and NF1 [AMT, CCL21, SPARCL1, RAB25, and BRCA1 [Cancer and its corresponding healthy tissue cell lines are indispensable in vitro models for discovering new biomarkers and pre-clinical drug testing. Due to its extreme heterogeneity, there are many problems with using OCs cell lines as models for so many different OCs subtypes. One of the biggest problems is often misclassification of commonly used cell lines with respect to their tumor subtype . Domcke nd STK11 . This isnd CDK12 . TCGA an and NF1 . Methyland BRCA1 . Considend BRCA1 .https://web.expasy.org/cellosaurus/) (accessed on 7 October 2021) [https://sites.broadinstitute.org/ccle/) (accessed on 7 October 2021) [https://cancer.sanger.ac.uk/cell_lines) (accessed on 7 October 2021) [One of the best and largest resources on cell lines is the Cellosaurus (er 2021) . Furtherer 2021)  and the er 2021)  contain Non-coding RNAs (ncRNAs) are a large class of RNA molecules that are translated but do not encode proteins. This class includes a wide range of different RNA molecules, which can be broadly classified into infrastructural ncRNAs and regulatory ncRNAs. Infrastructural ncRNAs include transfer RNAs (tRNAs), ribosomal RNAs (rRNAs), and small nuclear RNAs (snRNAs) and their functions are well-known and have been examined in detail . RegulatLncRNA molecules are transcribed by RNA Polymerase II and processed in a way that resembles mRNA processing, as they are often 5′ capped, 3′ polyadenylated, and spliced similarly to mRNAs . It has Biogenesis of lncRNAs is based on their location in respect to protein-coding genes, and lncRNAs can thus be classified into four categories: (1) long intergenic non-coding RNAs (lincRNAs), transcribed intergenically from both strands; (2) sense intronic transcripts, located within introns of coding genes without intersecting with exons; (3) sense overlapping transcripts, which overlap with the exons of coding genes on the same strand; and (4) antisense RNAs, which are located within the exons and introns of protein-coding genes but on the opposite strand   60,61,6,63. The Mutations and genomic rearrangements can affect the expression of lncRNA in the same way as they affect the protein-coding genes and can contribute to tumorigenesis. Aznaourova et al., have summarized a list of lncRNAs involved in various human diseases, including gynecological cancers . RegulatInitial systematic large screening of lncRNA genes, using genome-wide chromatin-state maps by immunoprecipitation, identified over a thousand highly conserved lncRNAs . The curXIST, which is involved in X-chromosome inactivation by direct interaction with the chromatin [HOTAIR, which is transcribed from the homeobox transcription factor cluster (HOX) in tightly controlled conditions; PANDAR, which is induced by DNA damage; LINC-ROR, which is associated with reprogramming to induced pluripotent stem cells; and COLDAIR, which is induced by cold [LncRNAs are considered to signal molecules when they regulate the transcription of target genes. In this context, lncRNA can exert this effect alone, or in combination with transcription factors. Their expression is triggered by specific conditions, and they in turn trigger specific responses to those conditions. The best-known example of this type of regulation is the lncRNA hromatin . Other e by cold .When acting as decoys, they usually block specific molecular pathways by binding to a specific protein or RNA and impairing its function. This is the most common type of regulation that lncRNAs exert on their targets. The targets are most often miRNA molecules, and lncRNAs antagonize the miRNA they target by sequestering the miRNA away from their intended mRNA targets . CompetiHOTAIR is one such lncRNA, often found overexpressed in tumors and associated with cancer metastases [Guide lncRNAs direct the localization of ribonucleoprotein complexes to specific targets. This effect can be achieved in cis, when they affect neighboring genes, or in trans when the effect is on distant genes. These effects are mediated through changes in the structure of chromatin. Regulation in cis involves specific interaction between the lncRNA and chromatin at its promoter, leading to accumulation of proteins involved in histone 3 lysine 9 (H3K9) methylation and gene silencing. Regulation in trans often targets proteins of the Polycomb Repressive Complex (PRC) and changes their localization, activity, and occupancy, leading to changes in chromatin structure in trans. tastases .CDKN2B-AS1, a lncRNA located in the INK4b/ARF/INK4a locus, recruits multiple chromatin-modifying proteins and thereby modulates transcriptional activity of the locus [When acting as scaffolds, they facilitate the interaction of different molecules and proteins. he locus . It is i2+-ATPase, mRNA decay, and mitochondrial activity. They can also be involved in metabolic reprogramming of several cancers, such as colon, liver, esophageal, and breast cancer, and melanoma [H19 [Even though lncRNAs were originally defined as RNA which do not encode proteins, recent reports suggest that some lncRNAs contain open reading frames (ORF) and may encode peptides . These pmelanoma . Furtheroma [H19 .SAMMSON, HOTAIR, H19, HOTTIP, and MEG3, but also some specific ones, like CEROX1 (cytoplasmic endogenous regulator of oxidative phosphorylation 1), which affects the process of oxidative phosphorylation. Mitochondria-encoded lncRNAs are either antisense mitochondrial transcripts, like lncND5, lncND6, lncCYB, and MDL1AS; chimeric mitochondrial transcripts, like ASncmtRNA-1 and ASncmtRNA-2; or putative mitochondrial DNA-encoded lncRNAs, like LIPCAR.LncRNAs can be found in different cellular compartments, from the nucleus to cytoplasm and mitochondria, and even exported from the cell via exosomes. About 30% of lncRNAs are located in the nucleus, where they can interact with transcription factors, chromatin complexes, and heterogenous ribonucleoprotein complexes . Within UCA1, FAM225A, RAMP2-AS1, POU3F3, HOTAIR, CCAT2) have been identified that affect the endothelial cells of blood vessels and stimulate angiogenesis [H19, which is highly expressed in tumor stroma in comparison to tumor tissue. This lncRNA promotes stemness and chemoresistance of cancer cells and increases the frequency of tumor-initiating cells [Exosomes are bi-layered membrane vesicles secreted from the cells, 30–150 nm in diameter, which can contain a wide range of molecules usually found within the cells. They are generated by the budding of the endosomal membrane. LncRNAs are packed inside exosomes whereby they interact with RNA-binding proteins through specific motifs. Exosomes are used in cell-to-cell communication, and whatever is packed inside an exosome may be delivered to a receiving cell and trigger a specific molecular response in that cell. In the case of tumor-derived exosomes, these responses range from tumor growth, invasion, and metastasis to angiogenesis and reprogramming of the tumor microenvironment. Furthermore, several lncRNAs  or inhi [HOTAIR , HULC [9IR [HULC  and RP11135L22.1 ) autopha135L22.1 . For insINC00504 , NRCP [104 [NRCP , LINC000INC00092 , and H19 and FGF , while DF [DANCR  and HNF1NF1A-AS1  can promDICER and molecular sponge function for reducing the regulatory effects of miRNAs [RB1 promoter (RB1-DT). Antigen presentation can be affected by the specific reduction of the abundance of antigen-presenting cells (lincRNA LINC01139) or by the regulation of pro-inflammatory cytokines. EGILA can affect the differentiation of T lymphocytes, thereby affecting immune cell priming and activation. LncRNAs can also affect immune cell migration and infiltration, and affect recognition and attack of cancer cells [HOTTIP was cited as the only lncRNA associated with the avoidance of immune surveillance by increasing IL6 expression in ovarian tumor cells, which triggers PD-L1 expression through the STAT3 pathway in neutrophils [LncRNAs play a role in the regulation of immune response, where they are involved in several mechanisms of action. A major role is antisense silencing associated with f miRNAs . Many ster cells . HOTTIP trophils . TherefoGAS5, increase the radiosensitivity of cancer cells through their sponging mechanisms. In contrast, other lncRNAs, such as HOTAIR or TUG1, can increase radioresistance by sponging specific miRNAs. Expression of lncRNAs can also be used as biomarkers of radiation damage, as lncRNA TP53COR1, TUG1 and MEG3 have been found to be upregulated after radiation damage by multiple studies [Resistance to radiation can be modulated positively and negatively by the lncRNAs. Some lncRNAs, such as  studies . IncreasHOTAIR, H19, MALAT1, LINC-ROR, HOTTIP, NEAT1, LNCRNA-ATB, and others [EMT is a reversible process during which epithelial cells acquire mesenchymal characteristics, including reduction of cell-cell contacts, changes in cell morphology, and increase of migratory capability. This transition is considered one of the crucial steps during tumor invasion and metastasis. The process is reversible, and under the right conditions, the cells can transition back from mesenchymal to the epithelial phenotype, resulting in mesenchymal to epithelial transition (MET). EMT process is regulated by specific transcription factors such as SNAIL, SLUG, TWIST1, TWIST2, ZEB1, and ZEB2 . Cancer d others .MALAT1, NEAT1, H19, GAS5, and MEG3 [Cell-to-cell communication and the microenvironment are important factors during tumor progression and metastasis. Tumor cells interact with their environment and various cell types in their surroundings. The most abundant and relevant cell types in this microenvironment are the cancer-associated fibroblasts (CAF), which respond to the cytokines produced by the tumor to support tumor growth and dissemination. Many lncRNAs are upregulated in the CAF compared to normal fibroblasts, such as and MEG3 ,111. Theand MEG3 . InterruPost-translational modifications (PTMs) of proteins are involved in several biological phenomena including signaling processes that occur at different stages of tumor development ,113. AltLncRNAs interfere with PTMs in the cytoplasm . They maH19 through repressing the methylated regions. It also affects the adjacent insulin-like growth factor 2 gene and associated proteins [LNCPRESS1 binding to SIRT6 and preventing its binding to histones [GClnc1 which acts as a scaffold for WDR5, and KAT2A proteins [Histones are subjected to several PTMs including methylation, acetylation, phosphorylation, and ubiquitination . It has proteins . Both alproteins  and insuproteins ,118. Lnchistones , or by aproteins .LncRNA-AKT interactions were experimentally shown in lung cancer [It is well-known that phosphorylation of proteins is one of the most common mechanisms that regulate protein activity, and phosphorylation is often dysregulated in cancer. AKT and mTOR phosphorylation have been detected as potential biomarkers for OC and tumor growth . LncRNA-g cancer  which miThe majority of the proteins are glycosylated and glycosylation plays a crucial role in cancer biology  and servBoth bioinformatical and experimental studies have discovered that lncRNAs prompt PTMs at different levels. The outcomes need to be further investigated to unravel the possible mechanisms leading to accurate diagnosis and effective treatments.H19, NEAT1, MALAT1, HOTAIR, or XIST, participate in this cellular process [LncRNAs, primarily through their crosstalk with miRNAs, regulate the osteogenic differentiation of mesenchymal stem cells (MSCs), a population of stromal cells in the bone marrow, and other anatomical regions such as adipose tissue and apical papilla of the tooth . MSCs ar process . Althoug process , MSCs co process  and prom process . In OCs, process . It was  process , while b process . Bu et a process .BCAL8 has been found amplified in breast cancer and associated with poor clinical outcomes of OC [CXCL11, CXCL10, and CXCR3 expression; differentiated, characterized by MUC16 and MUC1 expression; proliferative, characterized by HMGA2, SOX11, MCM2, and PCNA overexpression and MUC1 and MUC16 downregulation; and mesenchymal, characterized by high expression of HOX genes, FAP, ANGPTL2 and ANGPTL11 [MIAT , proliferative types show downregulation of NEAT1 and UCA1, while serous subtypes show frequent amplification of OVAL [TCGA data has been used to analyze lncRNA in different tumor types, but OC has not been analyzed in more detail because the TCGA database lacks the appropriate healthy tissue controls for HGSOC samples, thus making the differential expression analysis impossible for OC ,140. Howes of OC . HGSOC cANGPTL11 . MesenchRUNX1-IT1, MALAT1, H19, HOTAIRM1, LOC100190986, and AL132709.8 lncRNAs [MALAT1 and H19 have been extensively studied in OC, along with several other lncRNAs: HOTAIR, NEAT1, XIST, MEG3, and UCA1. Most extensively analyzed lncRNAs in OC have been listed in Several lncRNAs have been found to have an effect in a wide range of human cancers, including many gynecological cancers. In OC, a specific signature of six lncRNA has been identified by a bioinformatical analysis. This signature associates  lncRNAs . Of thesH19 imprinted maternally expressed transcript produces a 2.3 kb long RNA transcript, which is abundantly expressed during embryonic development and downregulated after birth. It is a paternally imprinted gene, but imprinting loss, and subsequent overexpression, have been associated with ovarian tumors [H19 can act as a competing endogenous RNA of miR-370-3p, resulting in the promotion of TGFB1-induced EMT [H19 locus are associated with platinum-based chemotherapeutic response [H19 can also affect cancer cell metabolism, through the sponging effect of miR-324-5p, which regulates PKM2, a major contributor to the Warburg effect [H19 has also been examined in some ROCs. H19-overexpressing choriocarcinoma cells were found to be more tumorigenic in vivo, even though there was no difference in their clonogenicity in the in vitro assays. There is a selection of cells expressing high levels of H19 during the microevolution of tumor progression, which suggests that this lncRNA does not act as a tumor-suppressor [H19 imprinting has also been demonstrated in pediatric germ cell tumors, and it may reflect the origin of these tumors in different stages of germ cell development [H19 hypomethylation, and DNA prepared from cultured teratoma cells shows extreme hypomethylation of the H19 locus [H19 binds to miR-19b, resulting in upregulation of CTFG, increase in cell proliferation, d reduction in the rate of apoptosis in these cells [A locus for the n tumors ,143. Knouced EMT , and as uced EMT . H19 is uced EMT . Its dowuced EMT ,148. Polresponse . H19 cang effect . Althougppressor . Loss ofelopment ,152,153.19 locus . Ovarianse cells .HOTAIR) has shown some potential as a diagnostic and predictive biomarker. This lncRNA acts as a molecular scaffold and binds the Polycomb Repressive Complex 2 (PRC2) on its 5′ domain and the lysine-specific histone demethylase 1A (LSD1)/CoREST/REST complex on its 3′ domain, bringing them in close proximity and methylating lysine 27 and demethylating lysine 4 of histone H3, leading to consequent gene silencing [HOTAIR promotes proliferation, stemness, and epithelial-to-mesenchymal transition of OC cells [HOTAIR is induced by estrogen, making it a relevant lncRNA in the context of gynecological cancers [HOTAIR may in some populations affect OC susceptibility [HOTAIR expression is also associated with chemoresistance in clinical samples and in vitro models, and its knockdown can lead to increased sensitivity to cisplatin and carboplatin both in vitro and on a mouse xenograft model [HOTAIR has been successful in reducing ovarian tumor growth in vitro and in vivo, and improved survival of xenograft mice, and has been suggested as a potential new therapeutic approach for the treatment of OC [HOX transcript antisense RNA , also known as nuclear-enriched abundant transcript 2 (NEAT2), is another lncRNA significantly overexpressed in various cancers [MALAT1 could be a novel biomarker in various cancers, including ovarian [MALAT1 and increased secretion through their exosomes, and this activates angiogenesis-related genes in the endothelial cells [MALAT1 is highly overexpressed in OC and is associated with the FIGO stage. Its overexpression leads to increased cell proliferation, migration, and invasion [MALAT1 has also been found to downregulate RBFOX2, which leads to the alternative splicing of the KIF1B and production of the pro-apoptotic long isoform of KIF1B, ultimately resulting in inhibition of anoikis [Metastasis-associated lung adenocarcinoma transcript 1  lncRNA has been reported as a tumor suppressor. Its major role is in the positive regulation of the tumor suppressor gene TP53 [MEG3 is downregulated in many cancers, such as breast [MEG3 promoter, as treatment with demethylating agent 5-aza-2-deoxycytidine increases MEG3 expression. Increased expression of MEG3 suppresses proliferation and growth and induces apoptosis, and suppresses tumorigenesis in vivo [MEG3 induces expression of PTEN and LAMA4, leading to inhibition of cell proliferation, cell cycle arrest, and induction of apoptosis [MEG3 is associated with better progression-free survival and overall survival in HGSOC, even though the same authors demonstrated that MEG3 is downregulated in HGSOC cell lines compared to the normal fallopian tube and ovarian cell lines, and upregulation of MEG3 in HGSOC cells leads to inhibition of tumor growth in vitro and in vivo [MEG3 is one of the three signature lncRNA that can be used to predict cisplatin resistance in OC. Upregulated PVT1 and downregulated TUG1 and MEG3 have high sensitivity and specificity in predicting chemoresistance and are negatively associated with OS and progression-free survival [MEG3 promoter, sponging of miR-214 by MEG3, and consequent reduction of drug resistance [MEG3 expression can be negatively regulated by another lncRNA: AGAP2-AS1, which is upregulated in OC and participates in cancer cell proliferation [Maternally expressed 3  is another lncRNA that is overexpressed in various cancers, including OC. NEAT1 is upregulated in OC, positively correlated with FIGO stage, tumor grade, and distant metastasis. NEAT1 expression level is an independent factor in predicting the overall survival of OC patients [NEAT1 expression is indeed significantly associated with poor overall survival, larger tumor size, lymph node metastasis, distant metastasis, TNM-stage, poor differentiation, and invasion depth [NEAT1 has been proposed as a prognostic biomarker in breast, ovarian, cervical, endometrial, and vulvar cancers [NEAT1 is also involved in the development of resistance. In the platinum-resistant OC cells, NEAT1 binds miR-770-5p, leading to upregulation of PARP1. Knockdown of NEAT1 expression results in a reduction in xenograft tumor growth as well as increases sensitivity to cisplatin [NEAT1 is upregulated in PTX-resistant OC tissues and cells and binds to miR-194. NEAT1 knockdown enhanced the sensitivity of cells to PTX through the miR-194/ZEB1 axis [NEAT1 as a possible diagnostic marker has been proposed in several cancers, such as prostate [NEAT1 is one of the proposed lncRNA in this panel [Nuclear Paraspeckle Assembly Transcript 1  is an oncogenic lncRNA found to be upregulated in many solid tumors. A meta-analysis revealed that upregulation of UCA1 is negatively associated with overall survival and progression-free survival in many cancers, including OC [UCA1 acts as a sponge for miR-485-5p, which in turn upregulates the levels of MMP14, and this upregulation of MMP14 is an important factor in OC metastasis [UCA1 expression induces cisplatin resistance in OC cell lines. This could be mediated through the upregulation of SRPK1 [UCA1 expression, by regulating the miR-654-5p/SIK2 axis [Urothelial cancer associated 1  regulates X-chromosome inactivation, by acting as a scaffold for repressive epigenetic factors, and as many as 30 different RNA-binding proteins are predicted to bind with XIST. XIST RNA contains structured regions, or Xist motifs, which are crucial for its function. Of these, the A-repeat (RepA) folds into a stem-loop structure and is required for gene silencing [XIST is associated with poor overall survival, larger tumor size, increased distant metastases, and advanced tumor stage in a range of cancers [XIST has been found to be downregulated and correlated to better prognosis in OC in one study [XIST was upregulated in OC tissues and cell lines and is suggested as an independent predictor of prognosis for OC patients [XIST in OC are also contradictory–some claim upregulation of XIST leads to stimulation and increased proliferation of OC cells, while others claim it suppresses OC proliferation and tumor growth [X inactive specific transcript  is upregulated in the plasma of patients with polycystic ovary syndrome (PCOS). This was also demonstrated in the ovarian granulosa cell tumor cell line KGN, where it leads to upregulation of IL6, and decreased apoptosis rate of these cells [HCP5) promotes cell proliferation and inhibits apoptosis in the KGN cell line through the miR-27a-3p-IGF1 axis [NPTN-IT1, or lncRNA-LET) is downregulated in KGN cells, and its overexpression inhibited cell viability and migration and promoted apoptosis [LncRNA growth arrest-specific 5 (se cells . HLA comGF1 axis . In contpoptosis .LINC00324) has been found in immature ovarian teratocarcinoma (IOT) tissues and cells. LINC00324 acts as a miR-214-5p sponge, thereby removing its inhibition of CDK6, CCND1, MDM2, and MDM4, consequently increasing IOT cell proliferation and decreasing apoptosis [Upregulation of long intergenic non-protein coding RNA 324 (poptosis .NBAT1) as a marker of favorable prognosis in OC. The study included 46 serous OC and 11 OC tumors of different origins, but there was no additional information on these other subtypes. However, the authors state that there was no difference between histological subtypes, suggesting that this marker is applicable for ROCs as well [A study by Yan et al., identified neuroblastoma-associated transcript 1 , cell-free tumor DNA (ctDNA), and non-coding RNAs . Circulasurvival . Exosomarognosis . LOXL1-Ar in EOC . A meta-r in EOC . The maj [MALAT1 . Soda etomarkers . It is aomarkers . More stExpression levels of circulating extracellular or exosome/EV lncRNAs associated with body fluids such as plasma/serum could serve as a potential biomarker for routine usage and a complementary liquid biopsy for the risk of ovarian tumor metastasis, recurrence, drug resistance, and potentially early detection. As single markers sometimes lack sensitivity and specificity, designing biomarker panels has been suggested as a good option for early detection, diagnosis, and prediction of recurrence. Such panels of lncRNAs have already been proposed for hepatocellular , liver , bladderThe important role of lncRNAs in various biological processes related to carcinogenesis, together with their cancer-specific expression patterns, has made lncRNAs promising therapeutic targets. Therefore, many strategies have been developing for their targeting ,263. GenOncogenic lncRNAs are overexpressed in cancers so their expression can be suppressed using various, mostly nucleic acids-based techniques. Most commonly used methods are based on RNA interference (RNAi), like small interfering RNAs (siRNAs) or short/small hairpin RNAs (shRNAs) . siRNAs MALAT1, which is overexpressed in both common and rare OCs, by ASOs, inhibited tumor growth and metastasis of breast [XIST [BDNF-AS, a NAT that represses transcription of brain-derived neurotrophic factor (BDNF) gene [BDNF, which promotes survival, migration, and attachment of tumor precursors originated from TP53-mutated fallopian tube epithelial cells, precursors of HGSOC [HOTAIR, MALAT1, MEG3, and GAS5 [LncRNA expression can also be suppressed using antisense oligonucleotides (ASOs), locked nucleic acid GapmeRs (LNA GapmeRs), or antagonists to natural antisense transcripts (antagoNATs) . ASOs arf breast  and lungf breast . LNA Gapf breast . LNAs hast [XIST , a lncRNst [XIST . AntagoNst [XIST . The firNF) gene . This apof HGSOC . AntagoNand GAS5 .SMN-AS1, an antisense transcript that represses expression of survival motor neuron 2 (SMN2) gene by recruiting the PRC2 to its locus [HOTAIR [XIST [N6-methyladenosine (m6A) modifications [MALAT1 [XIST [HOTAIR [GAS5 [DANCR [Other methods used for silencing lncRNA expression are mixmers and deoxy/ribozymes. Mixmers are built of chemically modified nucleotides like LNAs and different types of monomers. They sterically inhibit interactions between lncRNAs, ribonucleoproteins, or nucleic acids. They are used for preventing the formation of epigenetic remodeling complexes, altering gene expression and alternative splicing, repairing defective RNAs, and restoring protein production . So far,ts locus . For tre [HOTAIR  or XIST IR [XIST . DeoxyriIR [XIST . SimilarIR [XIST . A site-ications . In the  [MALAT1 , XIST [2T1 [XIST , HOTAIR  [HOTAIR , GAS5 [2IR [GAS5 , or DANC5 [DANCR  contain 5 [DANCR .MALAT1 [XIST [HOTAIR [NEAT1 [UCA1 [HOTAIR polymorphism rs920778 [Gene-editing methods like zinc finger nucleases (ZFNs), transcription activator-like effector nucleases (TALENs), and clustered regularly interspaced short palindromic repeats/CRISPR-associated protein 9 (CRISPR/Cas9) system can be used to suppress lncRNA expression ,289. It MALAT1 , XIST [2T1 [XIST , HOTAIR  [HOTAIR , NEAT1 [R [NEAT1  or UCA1 T1 [UCA1 . Furtherrs920778 .SNHG5 is reduced in paclitaxel-resistant OC patients, either SNHG5 overexpression or miR-23a inhibition could enhance paclitaxel sensitivity [UCA1 can sponge miR-654-5p, while its knockdown enhances miR-654-5p expression, which reduces ovarian tumor cells viability in vitro and in vivo [Manipulation with lncRNAs expression levels with any of the aforementioned methods could be used to interfere with the function of lncRNAs as miRNA sponges. Increased expression of lncRNAs that bind oncomiRs or decreased expression of lncRNAs that bind tumor-suppressor miRNAs could normalize gene regulatory network and signaling pathways, and reverse malignant phenotype, just like using miRNA mimics or antagomiRs . For inssitivity . Similar in vivo .HOTAIR [H19 [MALAT1 [NEAT1 [XIST [HOTAIR [HOTAIR-EZH2 and BDNF-AS-EZH2 [MALAT1 [HULC, a lncRNA that interacts with phenylalanine hydroxylase (PAH) and modulates its function. HULC depletion causes reduced enzymatic activities of PAH, which is a characteristic of metabolic disorder phenylketonuria. The introduction of HULC mimics successfully restores the function of that liver lncRNA and reduces excess phenylalanine levels [As mentioned above, the second general therapeutic approach for targeting lncRNAs in OC would be to abolish their function by inhibiting their interactions with other macromolecules, either through competition or steric blockade. There are several approaches including aptamers, nanobodies, small molecules, and RNA decoys . AptamerHOTAIR  and H19 AIR [H19 , which cAIR [H19 . They haAIR [H19 . NanobodAIR [H19 , and sin [MALAT1 , NEAT1 [1 [NEAT1 , XIST [2T1 [XIST , or HOTA [HOTAIR  are well [HOTAIR ,314. Sim-AS-EZH2 . Further [MALAT1 ,317. RNA [MALAT1 . One suc [MALAT1 . Anothere levels . TherefoH19 promoter and it is used for treating cancers with high H19 expression such as OC [Regulatory regions of lncRNAs could be also used for constructing more efficient drugs. There exists a DNA plasmid called H19-DTA (BC-819) that carries the gene for A subunit of diphtheria toxin under the regulation of the ch as OC . Its safch as OC .All previously described methods consider targeting a lncRNA of interest as a primary therapeutic goal for treating OCs. However, targeting lncRNAs could also be used to enhance the efficiency of already applied therapeutic regimes, since for many OC-related lncRNAs described in this paper their involvement in resistance to radio- and chemotherapy was mentioned. This has been comprehensively reviewed in ,324.Although constantly on the rise in recent years , RNA-basExpanding interest in lncRNA research has led to the accumulation of a vast amount of knowledge that has to be properly analyzed, organized, and made available for the wider scientific community. Therefore, a constantly growing number of web resources and bioinformatical tools have been developed that can help many different aspects of lncRNA research ,328. HowRecently we celebrated the 20th anniversary of publishing the draft human genome sequence. Initially, only about 2% of the human genome was reported to comprise protein-coding genes, and the rest referred to as “junk” DNA, it has become increasingly evident that this “junk” DNA is a goldmine for many regulatory non-coding transcripts. One type of such transcript is the lncRNAs. Consequently, their mechanisms of action and the molecular processes which they regulate are still being unraveled. As anticipated, their causative roles in the development and progression of many human neoplasms, including OCs, are becoming increasingly evident.The major drawback in discovering the (in)distinctive roles of lncRNAs in common and rare OCs is the lack of studies that clearly and properly separate the OC subtypes. One potential reason for that could be both clinicians’ and researchers’ inexperience in diagnosing rare gynecological cancers. On the other hand, the manuscript reviewers should insist that authors need to put more effort into describing their clinical samples. Hopefully, international collaborations such as the GYNOCARE COST Action will contribute to a more unified and standardized diagnosis and classification of ROCs .Long non-coding RNA molecules are promising diagnostic and prognostic biomarkers for ROCs . Current


The mean post-vaccination severity of the worsening episodes increased from PASI 3.1 to 8.0 (p < 0.001). Three patients showed morphologic change from chronic plaque-type to guttate psoriasis. Deterioration of psoriasis following COVID-19 vaccination was not associated with age, sex, disease duration, psoriatic arthritis, family history of psoriasis, history of erythroderma, current biologics use, comorbidities, vaccine types, human leukocyte antigen (HLA)-C genotypes, baseline PASI nor pre-vaccination PASI. For those who received two doses of vaccination, all but one patient aggravated after the first shot but not the second. The mechanism of psoriasis exacerbation in immunized individuals is unclear, but Th17 cells induced by COVID-19 vaccines may play a role. In the pandemic era, psoriasis patients and physicians should acknowledge the possibility of fluctuation of disease activity when vaccinated against COVID-19. Nevertheless, compared to a treatable dermatologic disease with rapid resolution of exacerbation, psoriasis patients who do not have contraindications to vaccination should benefit from COVID-19 vaccines in the prevention of severe COVID-19 infection and fatality.The temporal association had been reported between vaccination and exacerbation of psoriasis, and episodes of psoriasis flare-up have recently been attributed to COVID-19 vaccines. We recruited 32 unimmunized controls and 51 vaccinated psoriasis patients, 49 of whom were under biological therapy, with regular clinic visits receiving a total of 63 shots of vaccines, including 30 doses of Moderna mRNA-1273 and 33 doses of AstraZeneca-Oxford AZD1222. Fifteen episodes of exacerbation attacked within 9.3 ± 4.3 days, which is higher than two episodes in the control group ( Psoriasis is a chronic immune-mediated cutaneous inflammatory disease that may be precipitated by drug, infection, stress, physical trauma, and vaccination –6. A lowThis study aims to evaluate the clinical characteristics and genetic factors in the aggravation of psoriasis after COVID-19 vaccination.The study was approved by the Research Ethics Committee of National Taiwan University Hospital (201904124RINC). Consecutive patients with moderate to severe psoriasis who received COVID-19 vaccines in our dermatologic outpatient clinic between June 2021 and October 2021 were enrolled for analysis. Therapeutic inclusion criteria include patients under biologics and patients under remission after discontinuation of biologics, currently with/without traditional systemic treatment. The types of COVID-19 vaccine were documented, either Moderna mRNA-1273 or AstraZeneca-Oxford AZD1222. All patients were tested for human leukocyte antigen-C (HLA-C) genotypes. The baseline Psoriasis Area Severity Index (PASI) was defined as the most severe PASI before the initiation of current biological treatment, while the pre-vaccination PASI was defined as the PASI before receiving COVID-19 vaccines. Worsening of vaccinated patients was defined as (1) worsening of 50% PASI from a prior visit, which was based on an interval of 4–12 weeks depending on the biological agents, or (2) morphologic change, for example, chronic plaque-type to guttate, pustular or erythrodermic psoriasis, without other identifiable aggravating factors within 14 days of vaccination. Psoriasis area and severity index (PASI) was assessed at each clinic visit by the same physician. Aggravation of unvaccinated patients was defined as worsening 50% PASI compared to baseline PASI or morphological change. Possible precipitating factors, including upper respiratory tract infection, excess ultraviolet light exposure, alterations of medications, and psychological stress, are inquired orally.t-test was employed for quantitative variables. Pearson Chi-square test or Fisher's exact tests were applied for categorical data. The analysis results are two-tailed, with a significance level of 0.05.Statistics analysis was performed using SPSS version 25. Parametric data are presented as mean ± SD. To compare intergroup differences, Shapiro-Wilk test was applied to determine the data normality of distribution. Based on the result, Mann-Whitney or Student's n = 14) of the vaccinated group. In the unvaccinated control, age was 50.4 ± 12.7 years, body weight was 71.6 ± 13.3, and female patients accounted for 44%. Age, sex, and body weight are not statistically different between the vaccinated and control group. All of the patients suffered from long-lasting psoriasis, with a mean disease duration of 18.0 ± 10.0 and 18.1 ± 9.6 years in the vaccinated and unvaccinated group, respectively. In patients who received COVID-19 vaccines, psoriatic arthritis was diagnosed in 61%, history of erythrodermic change was recorded in 16%, and positive family history was found in 31%. Among individuals not receiving COVID-19 vaccines, the percentages of psoriatic arthritis, history of erythroderma, and family history of psoriasis stood at 50, 29, and 22%, respectively, showing no difference when each was compared with the unvaccinated counterpart.A total of 83 patients were recruited, including 51 vaccinated patients receiving 63 doses of vaccines and 32 patients who did not receive COVID-19 vaccines . COVID-1The comorbidities include hypertension in 13 (26%), diabetes mellitus in 9 (18%), cardiovascular disease in 3 (6%), hepatitis B virus infection in 5 (10%), and hepatitis C virus infection in 2 (4%) vaccinated patients, whereas 7 (22%) have hypertension, 4 (13%) have diabetes mellitus, and 4 (13%) hepatitis B virus infection in the unvaccinated group. None of the patients in the control group have documented cardiovascular disease or hepatitis C virus infection.p = 0.047). No specific aggravating factors, such as upper respiratory infection, excess ultraviolet exposure, change of medications, nor psychological stress, were reported in all patients. In the immunized group, three patients experienced morphologic changes from chronic plaque-type to guttate type . The mean post-vaccination PASI of the worsening episodes significantly increased from 3.1 to 8.0 (p < 0.001), while the BSA increased from 2.4 to 8.0 (p = 0.061). In comparison, the mean post-vaccination PASI of the episodes not associated with exacerbation was stable over time , and the BSA are not significantly different .The mean pre-vaccination PASI scores between those who deteriorated and the counterpart group are not significantly different , ixekizumab (n = 12), risankizumab (n = 6), etanercept (n = 4), adalimumab (n = 4), adalimumab plus methotrexate (n = 3), secukinumab (n = 2), and brodalumab (n = 1). In 14 individuals with disease aggravation, they are receiving guselkumab (n = 3), ixekizumab (n = 2), risankizumab (n = 2), etanercept (n = 1), adalimumab (n = 1), adalimumab plus methotrexate (n = 2), secukinumab (n = 1), methotrexate (n = 1), and topical steroid (n = 1). Whether receiving biological agents or not was not associated with disease exacerbation following COVID-19 vaccination (p = 0.138).Regarding the treatment, only three patients were not receiving biologics; one was applying topical steroids, another taking methotrexate, and the other was taking acitretin. Forty-nine patients (94%) in the immunized group were under biological therapy, including guselkumab  . In consPsoriasis in four patients worsened after the first dose but not after the second. Three of them received AstraZeneca-Oxford vaccine, and one of them received Moderna vaccine. In addition to the possible triggering effect of COVID-19 vaccines, psoriasis severity may be altered by the effect of biologics, for example, time of initiation of the treatment course, duration of therapy, and the interval between COVID-19 vaccination and clinic visit. In our patients, two of them initiated guselkumab within 3 months before the first shot of COVID-19 vaccination. PASI response of patients receiving guselkumab increases with the duration of treatment . The patients/participants provided their written informed consent to participate in this study.Y-WH and T-FT contributed to conception and design of the study. Y-WH organized the database, performed the statistical analysis, and wrote the first draft of the manuscript. All authors contributed to manuscript revision, read, and approved the submitted version.T-FT has conducted clinical trials or received honoraria for serving as a consultant for Abbvie, Boehringer Ingelheim, Bristol-Myers Squibb, Celgene, Eli-Lilly, Galderma, Janssen-Cilag, Merck Sharp and Dohme, Novartis International AG, Pfizer Inc., and UCB Pharma. However, none of the above has direct conflict regarding this manuscript. The remaining author declares that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.