Secretory phospholipase A(2)-IIA overexpressing mice exhibit cyclic alopecia mediated through aberrant hair shaft differentiation and impaired wound healing response

Secretory phospholipase A(2) Group-IIA (sPLA(2)-IIA) is involved in lipid catabolism and growth promoting activity. sPLA(2)-IIA is deregulated in many pathological conditions including various cancers. Here, we have studied the role of sPLA(2)-IIA in the development of cyclic alopecia and wound healing response in relation to complete loss of hair follicle stem cells (HFSCs). Our data showed that overexpression of sPLA(2)-IIA in homozygous mice results in hyperproliferation and terminal epidermal differentiation followed by hair follicle cycle being halted at anagen like stage. In addition, sPLA2-IIA induced hyperproliferation leads to complete exhaustion of hair follicle stem cell pool at PD28 (Postnatal day). Importantly, sPLA(2)-IIA overexpression affects the hair shaft differentiation leading to development of cyclic alopecia. Molecular investigation study showed aberrant expression of Sox21, Msx2 and signalling modulators necessary for proper differentiation of inner root sheath (IRS) and hair shaft formation. Further, full-thickness skin wounding on dorsal skin of K14-sPLA(2)-IIA homozygous mice displayed impaired initial healing response. Our results showed the involvement of sPLA(2)-IIA in regulation of matrix cells differentiation, hair shaft formation and complete loss of HFSCs mediated impaired wound healing response. These novel functions of sPLA(2)-IIA may have clinical implications in alopecia, cancer development and ageing.