DHCR24缺乏通过调节脂质代谢失衡和胞质mtDNA诱导的cGAS-STING激活驱动年龄相关性睑板腺功能障碍

Abstract

Dysregulated lipid metabolism and chronic inflammation are hallmarks of aging, yet their interplay in age-related tissue disorders remains poorly defined. In the ocular surface, age-related meibomian gland dysfunction (ARMGD) is highly prevalent but mechanistically unclear, leading to significant visual impairment without targeted therapies. To identify key molecular drivers of ARMGD, we performed integrated multi-omics screening of aging mouse meibomian glands (MGs) and identified DHCR24, a key cholesterol metabolism enzyme, as a critical regulator of gland homeostasis. Single-cell sequencing identified age-associated downregulation of Dhcr24 predominantly in meibocytes. Based on this finding, we generated a meibocyte-specific Dhcr24 knockout (cKO) model, which exhibited typical ARMGD pathology including glandular atrophy, disrupted lipid homeostasis, and inflammatory activation. Further in vitro studies using SZ95 sebocytes demonstrated that DHCR24 deficiency induces mitochondrial dysfunction and cytosolic mitochondrial DNA (mtDNA) leakage, triggering cGAS/STING-dependent inflammatory senescence. Notably, AAV-mediated restoration of DHCR24 in mice reversed age-related gland pathology. Our findings establish DHCR24 as a dual-target regulator that maintains cholesterol metabolic homeostasis while suppressing mtDNA-driven inflammation via the cGAS-STING pathway, highlighting its therapeutic potential for ARMGD and related disorders characterized by lipid-inflammatory imbalance.