ROS production and mitochondrial dysfunction driven by PU.1-regulated NOX4-p22^phox activation in Aβ-induced retinal pigment epithelial cell injury

Abstract

Rationale: Amyloid β (Aβ) deposition, an essential pathological process in age-related macular degeneration (AMD), causes retinal pigment epithelium (RPE) degeneration driven mostly by oxidative stress. However, despite intense investigations, the extent to which overoxidation contributes to Aβ-mediated RPE damage and its potential mechanism has not been fully elucidated. Methods: We performed tandem mass-tagged (TMT) mass spectrometry (MS) and bioinformatic analysis of the RPE-choroid complex in an Aβ 1-40 -induced mouse model of retinal degeneration to obtain a comprehensive proteomic profile. Key regulators in this model were confirmed by reactive oxygen species (ROS) detection, mitochondrial ROS assay, oxygen consumption rate (OCR) measurement, gene knockout experiment, chromatin immunoprecipitation (ChIP), and luciferase assay. Results: A total of 4243 proteins were identified, 1069 of which were significantly affected by Aβ 1-40 and found to be enriched in oxidation-related pathways by bioinformatic analysis. Moreover, NADPH oxidases were identified as hub proteins in Aβ 1-40 -mediated oxidative stress, as evidenced by mitochondrial dysfunction and reactive oxygen species overproduction. By motif and binding site analyses, we found that the transcription factor PU.1/Spi1 acted as a master regulator of the activation of NADPH oxidases, especially the NOX4-p22 phox complex. Also, PU.1 silencing impeded RPE oxidative stress and mitochondrial dysfunction and rescued the retinal structure and function. Conclusion: Our study suggests that PU.1 is a novel therapeutic target for AMD, and the regulation of PU.1 expression represents a potentially novel approach against excessive oxidative stress in Aβ-driven RPE injury.

MiR-22 modulates brown adipocyte thermogenesis by synergistically activating the glycolytic and mTORC1 signaling pathways

“…Oxygen consumption rate (OCR) and extracellular acidification rate (ECAR) assays were performed and analyzed as reported 29 , 30 . In brief, SVF cells from BAT of miR-22 KO mice or wild-type (WT) mice were seeded in an XFe24 cell culture microplate (Agilent) and differentiated into brown adipocytes.…”

Role of amyloid β-peptide in the pathogenesis of age-related macular degeneration

“… 40 Moreover, under the presence of transcription factor PU.1/SPI1 induced by Aβ, NADPH oxidase activation occurs and induces the expression of NADPH oxidase (NOX) complex, such as NOX4-p22 phox complex, leading to the outcome of mitochondrial dysfunction and excessive oxidative stress in RPE cells. 43 Silencing of PU.1/SPI1 has been shown to impede the process of ROS production and mitochondrial dysfunction and protect the retinal structure and function from oxidative damage. 43 This novel finding brings out new insight into preventing mitochondrial dysfunction induced by Aβ in RPE cells.…”

“… 43 Silencing of PU.1/SPI1 has been shown to impede the process of ROS production and mitochondrial dysfunction and protect the retinal structure and function from oxidative damage. 43 This novel finding brings out new insight into preventing mitochondrial dysfunction induced by Aβ in RPE cells. From above, it is suggested that Aβ could lead to the consequence of mitochondrial dysfunction in AMD.…”

ASMq protects against early burn wound progression in rats by alleviating oxidative stress and secondary mitochondria‑associated apoptosis via the Erk/p90RSK/Bad pathway

“…The effect of decreasing XO levels induced by burn injury was more significant in the high dosage ASMq group (P<0.01). Nox4 is an important member of the Nox family that can be used to indicate mitochondrial status ( 28 ). The effect of ASMq on Nox4 expression was similar to that of XO: Specifically, both high and medium dosage ASMq significantly decreased expression levels of Nox4 in the zone of stasis ( Fig.…”