Activation of the endoplasmic reticulum stress response by the amyloid-beta 1-40 peptide in brain endothelial cells.
Neurovascular dysfunction arising from endothelial cell damage is an early pathogenic event that contributes to the neurodegenerative process occurring in Alzheimer's disease (AD). Since the mechanisms underlying endothelial dysfunction are not fully elucidated, this study was aimed to explore the hypothesis that brain endothelial cell death is induced upon the sustained activation of the endoplasmic reticulum (ER) stress response by amyloid-beta (Aβ) peptide, which deposits in the cerebral vessels in many AD patients and transgenic mice. Incubation of rat brain endothelial cells (RBE4 cell line) with Aβ1-40 increased the levels of several markers of ER stress-induced unfolded protein response (UPR), in a time-dependent manner, and affected the Ca(2+) homeostasis due to the release of Ca(2+) from this intracellular store. Finally, Aβ1-40 was shown to activate both mitochondria-dependent and -independent apoptotic cell death pathways. Enhanced release of cytochrome c from mitochondria and activation of the downstream caspase-9 were observed in cells treated with Aβ1-40 concomitantly with caspase-12 activation. Furthermore, Aβ1-40 activated the apoptosis effectors' caspase-3 and promoted the translocation of apoptosis-inducing factor (AIF) to the nucleus demonstrating the involvement of caspase-dependent and -independent mechanisms during Aβ-induced endothelial cell death. In conclusion, our data demonstrate that ER stress plays a significant role in Aβ1-40-induced apoptotic cell death in brain endothelial cells suggesting that ER stress-targeted therapeutic strategies might be useful in AD to counteract vascular defects and ultimately neurodegeneration.
['Fonseca|Ana Catarina R G|AC|', 'Ferreiro|Elisabete|E|', 'Oliveira|Catarina R|CR|', 'Cardoso|Sandra M|SM|', 'Pereira|Cláudia F|CF|']
D051702:Activating Transcription Factor 6 D016229:Amyloid beta-Peptides D000818:Animals D017209:Apoptosis D001921:Brain D002118:Calcium D002462:Cell Membrane D002478:Cells, Cultured D003600:Cytosol D000091342:Endoplasmic Reticulum Chaperone BiP D059865:Endoplasmic Reticulum Stress D004730:Endothelium, Vascular D006801:Humans D020287:In Situ Nick-End Labeling D007770:L-Lactate Dehydrogenase D053078:Membrane Potential, Mitochondrial D051379:Mice D009336:Necrosis D010446:Peptide Fragments D011065:Poly(ADP-ribose) Polymerases D051381:Rats
Endoplasmic reticulum stress endoplasmic reticulum amyloid-beta Endothelial cells Endothelial cells Alzheimer's disease AD ER Aβ RBE4 unfolded protein response UPR Apoptosis apoptosis-inducing factor AIF 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide AM APP ATF Amyloid-beta peptide BBB CAAT/enhancer binding protein homologous protein CHOP Calcium homeostasis DMSO ECF ECs GAPDH GRP78 IRE1 JNK LDH LRP MTT NAD+ NADH PARP1 PERK PI PS PVDF RAGE RT Ry RyR SDS-PAGE SDS-polyacrylamide gel SERCA TATA-binding protein TBP TBS-T TBS-Tween TUNEL ThS WB Western blot X-box binding protein-1 XBP-1 acetoxymethyl ester activating transcription factor amyloid precursor protein bFGF basic fibroblast growth factor blood–brain barrier c-jun N-terminal kinase dimethyl sulfoxide eIF2α endothelial cells enhanced chemifluorescence glucose-regulated protein of 78kDa glyceraldehyde-3-phosphate dehydrogenase inositol-requiring protein-1 lactate dehydrogenase low-density lipoprotein receptor-related protein mitochondrial membrane potential nicotinamide adenine dinucleotide oxidized nicotinamide adenine dinucleotide poly(ADP-ribose) polymerase 1 polyvinylidene difluoride presenilinM propidium iodide protein kinase RNA-like ER kinase rat brain endothelial cell line receptor for advanced glycation end products room temperature ryanodine ryanodine receptor sarco/ER Ca(2+) ATPase terminal deoxynucleotidyl transferase dUTP nick-end labeling thioflavine S Δψmit α subunit of eukaryotic translation initiation factor 2