Fig. 1
From: Phospholipase A2 in skin biology: new insights from gene-manipulated mice and lipidomics
Expressions and functions of various PLA2s in mouse skin. sPLA2-IIF is localized in the suprabasal epidermis and produces P-LPE, which promotes epidermal hyperplasic diseases such as psoriasis and skin cancer. Epidermal sPLA2-IIF expression and thereby P-LPE production are augmented by IL-17A and IL-22 supplied by γδ T and Th17 cells in psoriasis. sPLA2-IIE is localized in hair follicles in synchrony with the growing phase (anagen) of hair cycling and may regulate hair homeostasis. sPLA2-IID is constitutively expressed in DCs and M2 macrophages in regional LNs and produces ω3 PUFA-derived anti-inflammatory lipid mediators, which put a brake on Th1 or Th17 immunity, thereby sequestering CHS and psoriasis and promoting skin cancer. PNPLA1 is expressed in the border of SG and SC, where it produces ω-O-acylceramide that is essential for skin barrier function. For details, please see the text