Mitochondrial Dysfunction During TGF-β1-Induced Epithelial-Mesenchymal Transition in Retinal Pigment Epithelial Cells.

Purpose: Epithelial-mesenchymal transition (EMT) of retinal pigment epithelial (RPE) cells contributes to the epiretinal membrane development in proliferative vitreoretinopathy (PVR). This study aimed at investigating changes in mitochondrial function during EMT in PVR.

Methods: Transmission electron microscopy (TEM) was utilized to examine the mitochondrial morphology in human PVR epiretinal membranes and retinal pigment epithelium of human donor eyes. Utilizing TGF-β1 induced EMT in ARPE-19 cells as an in vitro model, we assessed mitochondrial morphology using transmission electron microscopy (TEM), evaluated mitochondrial function through various assays including detection and analysis of mitochondrial membrane potential (MMP), mitochondrial deoxyribonucleic acid (mtDNA), reactive oxygen species (ROS), ATP, oxygen consumption rate (OCR), and extracellular acidification rate (ECAR). RNA sequencing was performed to identify differentially expressed genes (DEGs) related to mitochondrial function and PVR pathogenesis.

Results: Mitochondrial morphological damage was observed in human PVR epiretinal membranes. TGF-β1 treatment led to morphological changes in mitochondria, increased oxidative stress, mitochondrial membrane depolarization, and reduction in mtDNA, mitochondrial respiration, and ATP production, indicating mitochondrial dysfunction in EMT ARPE-19 cells. Furthermore, RNA sequencing data highlighted the dysfunction, showing downregulation of mitochondria-related pathways and mitochondrial transcription factor A (TFAM), crucial for mtDNA maintenance.

Conclusion: Our findings indicated that TGF-β1 treatment induced mitochondrial dysfunction in RPE cells during EMT, providing insights into the molecular mechanisms of PVR development.