Mitochondrial Dysfunction and Impaired Antioxidant Responses in Retinal Pigment Epithelial Cells Derived from a Patient with RCBTB1-Associated Retinopathy

Abstract

Mutations in the RCBTB1 gene cause inherited retinal disease; however, the pathogenic mechanisms associated with RCBTB1 deficiency remain poorly understood. Here, we investigated the effect of RCBTB1 deficiency on mitochondria and oxidative stress responses in induced pluripotent stem cell (iPSC)-derived retinal pigment epithelial (RPE) cells from control subjects and a patient with RCBTB1-associated retinopathy. Oxidative stress was induced with tert-butyl hydroperoxide (tBHP). RPE cells were characterized by immunostaining, transmission electron microscopy (TEM), CellROX assay, MitoTracker assay, quantitative PCR and immunoprecipitation assay. Patient-derived RPE cells displayed abnormal mitochondrial ultrastructure and reduced MitoTracker fluorescence compared with controls. Patient RPE cells displayed increased levels of reactive oxygen species (ROS) and were more sensitive to tBHP-induced ROS generation than control RPE. Control RPE upregulated RCBTB1 and NFE2L2 expression in response to tBHP treatment; however, this response was highly attenuated in patient RPE. RCBTB1 was co-immunoprecipitated from control RPE protein lysates by antibodies for either UBE2E3 or CUL3. Together, these results demonstrate that RCBTB1 deficiency in patient-derived RPE cells is associated with mitochondrial damage, increased oxidative stress and an attenuated oxidative stress response.

Inhibition of miR-143-3p Restores Blood–Testis Barrier Function and Ameliorates Sertoli Cell Senescence

“…According to more recent research, miR-143-3p was markedly up-regulated in the testicular heat stress model and might be a crucial regulatory element influencing spermatogenesis in hot stress [64]. Similarly, research on retinal epithelial cells has demonstrated that Nrf2, a vital transcription factor that withstands oxidative stress, may be bound to and regulated by UBE2E3 [65,66]. Intriguingly, an association has been found between post-traumatic stress disorder and UBE2E3 expression in neurons [66,67].…”

“…Similarly, research on retinal epithelial cells has demonstrated that Nrf2, a vital transcription factor that withstands oxidative stress, may be bound to and regulated by UBE2E3 [65,66]. Intriguingly, an association has been found between post-traumatic stress disorder and UBE2E3 expression in neurons [66,67]. Given our findings that the miR-143-3p/UBE2E3 axis induced Sertoli cell senescence, we proposed that factors inducing premature testicular aging-such as chemotherapy, oxidative stress, and heat stress-might lead to aberrant expression of miR-143-3p or UBE2E3.…”

Retinal Cell Biology in Health and Disease

“…Cells 2024, 13, 297. https://doi.org/10.3390/cells13040297 https://www.mdpi.com/journal/cells Mitochondrial dysfunction takes center stage in Huang et al's study, who examined impaired antioxidant responses in retinal pigment epithelial cells associated with RCBTB1related retinopathy [6]. This research not only provides insights into the pathophysiology of a specific retinal disorder but also underscores the broader significance of mitochondrial health in maintaining retinal function.…”