PIWIL-2 and piRNAs are regularly expressed in epithelia of the skin and their expression is related to differentiation.
PIWI proteins play multiple roles in germline stem cell maintenance and self-renewal. PIWI-interacting RNAs (piRNAs) associate with PIWI proteins, form effector complexes and maintain genome integrity and function in the regulation of gene expression by epigenetic modifications. Both are involved in cancer development. In this study, we investigated the expression of PIWIL-2 and piRNAs in normal human skin and epithelial tumors and its regulation during keratinocyte (KC) differentiation. Immunohistochemistry showed that PIWIL-2 was regularly expressed in the epidermis and adnexal tissue with strongest expression in sebaceous glands. Cell culture studies revealed an association of PIWIL-2 expression with the state of differentiated KC. In contrast, the PIWIL-2 expression pattern did not correlate with stem cell compartments or malignancy. piRNAs were consistently detected in KC in vitro by next-generation sequencing and the expression levels of numerous piRNAs were regulated during KC differentiation. Epidermal piRNAs were predominantly derived from processed snoRNAs (C/D-box snoRNAs), tRNAs and protein coding genes. Our data indicate that components of the PIWIL-2-piRNA pathway are present in epithelial cells of the skin and are regulated in the context of KC differentiation, suggesting a role of somatic gene regulation. However, putative roles in the maintenance of stem cell compartments or the development of malignancy in the skin were not supported by this study.
['Pammer|Johannes|J|', 'Rossiter|Heidi|H|', 'Bilban|Martin|M|', 'Eckhart|Leopold|L|', 'Buchberger|Maria|M|', 'Monschein|Laura|L|', 'Mildner|Michael|M|']
D000818:Animals D060565:Argonaute Proteins D001706:Biopsy D002454:Cell Differentiation D004817:Epidermis D005786:Gene Expression Regulation D059014:High-Throughput Nucleotide Sequencing D006801:Humans D015603:Keratinocytes D051379:Mice D061251:Primary Cell Culture D034741:RNA, Small Interfering D000081246:RNA-Seq D012627:Sebaceous Glands
piRNA Skin Keratinocyte Carcinoma Hili PIWIL2 ncRNA