Phosphatidylcholine modulates trabecular meshwork resilience to glaucomatous injury via regulation of TGFBR3 signaling

INTRODUCTION: Glaucoma is a main cause of irreversible blindness, which is mainly characterized by increased intraocular pressure (IOP) and degeneration of retinal ganglion cells. Current therapies primarily act by reducing aqueous humor production or enhancing its outflow to lower IOP. However, because glaucoma is a chronic disease requiring lifelong management, many patients experience reduced efficacy or develop tolerance to available medications over time. Consequently, there is an urgent need for novel pharmacological strategies that provide sustained IOP control. Dysfunction in human trabecular meshwork cells (HTMCs), which are crucial for the drainage of aqueous humor, significantly contributes to rising IOP. Phosphatidylcholine (PC) species have been recognized as potential therapeutic agents, but their causal relevance and mechanisms in glaucoma remain unclear. METHODS: We initially applied bidirectional Mendelian randomization (MR) analysis based on genome-wide associations of 648,214 individuals from European and East Asian ancestry to investigate the causal associations between 179 lipid species and glaucoma. We then explored the causal effects of PC(18:2/20:4) using HTMCs under hydrostatic pressure. The RNA sequencing, western blotting, immunofluorescence, proteomics, and flow cytometry were applied to explore the molecular mechanisms. RESULTS: MR results revealed that PC(18:2/20:4) functions as a protective factor for glaucoma (odds ratio = 0.89; 95% confidence interval = 0.82-0.96; P = 0.004) and no evidence for reverse causation was observed. In HTMCs, PC(18:2/20:4) could reduce the ROS production, inhibit apoptosis and fibrosis (Bax, Caspase-3, TGF-β2/3, MYOC), and recover the mitochondrial membrane potential. Transcriptomic and proteomic level data both demonstrated the activation of AMPK pathway and autophagy-related genes. Mechanistically, PC(18:2/20:4) activated AMPK via TGFBR3-dependent mechanism and inhibited mTOR. Meanwhile, blocking TGFBR3 reversed the beneficial effects. CONCLUSION: This integrative study demonstrated that PC(18:2/20:4) is a causal and relevant lipid modulator in pathogenesis of glaucoma. PC(18:2/20:4) protects HTMCs from pressure-induced oxidative stress, fibrosis, and apoptosis by activating the TGFBR3-AMPK/mTOR pathway. Our findings provide experimental basis for further development of lipid-based therapy to preserve HTMCs in glaucoma.