AbstractMutations in patatin-like phospholipase domain-containing 1 (PNPLA1) cause autosomal recessive congenital ichthyosis, but the mechanism involved remains unclear. Here we show that PNPLA1, an enzyme expressed in differentiated keratinocytes, plays a crucial role in the biosynthesis of ω-O-acylceramide, a lipid component essential for skin barrier. Global or keratinocyte-specific Pnpla1-deficient neonates die due to epidermal permeability barrier defects with severe transepidermal water loss, decreased intercellular lipid lamellae in the stratum corneum, and aberrant keratinocyte differentiation. In Pnpla1−/− epidermis, unique linoleate-containing lipids including acylceramides, acylglucosylceramides and (O-acyl)-ω-hydroxy fatty acids are almost absent with reciprocal increases in their putative precursors, indicating that PNPLA1 catalyses the ω-O-esterification with linoleic acid to form acylceramides. Moreover, acylceramide supplementation partially rescues the altered differentiation of Pnpla1−/− keratinocytes. Our findings provide valuable insight into the skin barrier formation and ichthyosis development, and may contribute to novel therapeutic strategies for treatment of epidermal barrier defects.
摘要位于马铃薯素磷脂酶结构域1(PNPLA1)的突变导致常染色体隐性遗传性先天性鱼鳞病,但涉及的机制尚不清楚。在这里,我们展示了PNPLA1是一种在分化的角质细胞中表达的酶,对于皮肤屏障必需的脂质成分ω-O-酰胺的生物合成起着至关重要的作用。全身或角质细胞特异性Pnpla1缺失的新生儿因表皮渗透屏障缺陷而死亡,伴有严重的经皮水分散失,角质层中间隔脂质减少和异常的角质细胞分化。在Pnpla1−/−表皮中,独特的亚油酸含量的脂质,包括酰胺、酰基葡糖酰胺和(O-酰基)-ω-羟基脂肪酸几乎不存在,其潜在的前体物质相应增加,表明PNPLA1催化ω-O-酯化与亚油酸形成酰胺。此外,酰胺补充部分挽救了Pnpla1−/−角质细胞的改变分化。我们的发现为皮肤屏障形成和鱼鳞病的发展提供了有价值的见解,并可能有助于治疗表皮屏障缺陷的新疗法策略。