부산대학교 도서관

Secretory phospholipase A2Group‐IIA (sPLA2‐IIA) catalyzes the hydrolysis of the sn‐2 position of glycerophospholipids to yield fatty acids and lysophospholipids. sPLA2‐IIA is deregulated in various cancers; however, its role in hair follicle stem cell (HFSC) regulation is obscure. Here we report a transgenic mice overexpressing sPLA2‐IIA (K14‐sPLA2‐IIA) showed depletion of HFSC pool. This was accompanied with increased differentiation, loss of ortho‐parakeratotic organization and enlargement of sebaceous gland, infundibulum and junctional zone. The colony forming efficiency of keratinocytes was significantly reduced. Microarray profiling of HFSCs revealed enhanced level of epithelial mitogens and transcription factors, c‐Jun and FosB that may be involved in proliferation and differentiation. Moreover, K14‐sPLA2‐IIA keratinocytes showed enhanced activation of EGFR and JNK1/2 that led to c‐Jun activation, which co‐related with enhanced differentiation. Further, depletion of stem cells in bulge is associated with high levels of chromatin silencing mark, H3K27me3 and low levels of an activator mark, H3K9ac suggestive of alteration in gene expression contributing toward stem cells differentiation. Our results, first time uncovered that overexpression of sPLA2‐IIA lead to depletion of HFSCs and differentiation associated with altered histone modification. Thus involvement of sPLA2‐IIA in stem cells regulation and disease pathogenesis suggest its prospective clinical implications. StemCells2016;34:2407–2417 Overexpression of sPLA2‐IIA in mice epidermis leads to hyperplasia of both interfollicular epidermis and sebaceous gland, with enlarged size of the junctional zone and dermal papillae. In addition, loss of self‐renewal in hair follicle stem cells was due to increased proliferation and differentiation, mediated through increased level of mitogenic signalling followed by enhanced expression of c‐Jun, FosB, and Nr4a1.