Sesamol reprograms mitochondrial dysfunction and metabolic signaling to rescue endothelial degeneration in Fuchs' endothelial corneal dystrophy.

PURPOSE: Fuchs' endothelial corneal dystrophy (FECD) is a progressive corneal disease characterized by loss of corneal endothelial cells (CEnCs), eventually leading to blindness. Though mitochondrial dysfunction remains the central cause for endothelial cell death, its underlying metabolic drivers remain poorly defined. Hence, there is a need to investigate novel therapeutic approaches targeting metabolic dysregulation, rather than relying solely on surgical intervention. This study aims to explore the metabolic dysregulation in FECD and identify plausible novel non-invasive therapeutics.

METHOD: Metabolomics was performed on aqueous humor (AH) obtained from FECD patients (n = 5). Corneal endothelial cells (iCEnCs) differentiated from induced pluripotent stem cells were exposed to oxidative stress using menadione (Mn) and assessed for barrier function, mitochondrial membrane potential, dynamics, biogenesis, mitophagy and apoptosis via immunofluorescence, qPCR and Western blot. Ex vivo human cadaveric corneal assays were done to evaluate CEnC barrier integrity and cell death. Potential therapeutic targets identified by AH metabolomics were further investigated using small molecule modulators for their ability to restore mitochondrial functionality.

RESULTS: Metabolomics revealed depletion of endogenous peroxisome proliferator-activated receptor (PPAR) ligands, sphingolipid imbalance and accumulation of xenobiotics in AH of FECD patients. Mn-treated iCEnCs revealed barrier breakdown (TEER ↓ 75%), mitochondrial depolarization (JC-1 ↓ 76 %), loss of Mfn2 (↓ 32 %) and PGC-1α (↓ 37%), accumulation of PINK1/Parkin and pro-apoptotic signaling mimicking FECD pathology. Gene expression of ion transport (SLC4A11), ECM genes (COL8A2) was down regulated, whereas expression of glycolytic genes (HK1 and GLUT1) showed upregulation. Supplementation with sesamol to Mn-treated iCEnCs most effectively restored mitochondrial potential (89% of control), normalized fusion-fission balance, reactivated PGC-1α and PPARγ, suppressed apoptosis (-85% BAX/Bcl2 ratio) and preserved barrier integrity.

CONCLUSION: Sesamol not only rescued compromised endothelial cells but also effectively reinstated cellular metabolic homeostasis by mitigating underlying oxidative stress and rectifying mitochondrial signaling imbalances.