DJ-1 protects retinal pericytes against high glucose-induced oxidative stress through the Nrf2 signaling pathway

Abstract

Oxidative stress has been associated with the etipathogenesis of Diabetic retinopathy (DR). Studies have shown that DJ-1 plays an important role in regulating the reactive oxygen species (ROS) production and resistance to oxidative stress-induced apoptosis. This study aimed to investigate whether DJ-1 upregulates oxidative stress and prevents damage to retinal capillary pericytes by increasing antioxidant capacity through the Nuclear factor erythroid 2-related factor 2 (Nrf2) signaling pathway. Nrf2 is a redox-sensitive transcription factor that encode antioxidant enzymes and phase II metabolic enzymes, activation of Nrf2 functions is one of the critical defensive mechanisms against oxidative stress in many tissues. Our results showed after DJ-1 overexpression, apoptosis of rat retinal pericytes (RRPs) decreased, the ratio of B-cell lymphoma-2 (Bcl-2) to BCL2-Associated X Protein (BAX) increased, the production of ROS decreased, and the protein expression and activity of manganese superoxide dismutase (MnSOD, also called SOD2) and catalase (CAT) increased. DJ-1 overexpression activated Nrf2 expression, however, after Nrf2 silencing, apoptosis of RRPs increased, the ratio of Bcl-2 to BAX decreased, the production of ROS increased, the protein expression of MnSOD and CAT decreased, and the expression of heme oxygenase-1 (HO-1), NADP(H) quinone oxidoreductase (NQO1), glutamate-cysteine ligase catalytic subunit (GCLC) and modifier subunit (GCLM) decreased. These data suggest that enhancement of the Nrf2 pathway is a potential protective strategy for the treatment of DR. Therefore, DJ-1 may prevent high glucose-induced oxidative stress and RRPs apoptosis through the Nrf2 signaling pathway, thereby preventing the early onset and progression of DR. Quantification of ROS. Cellular ROS production was evaluated by measuring the oxidative conversion of cell-permeable dichlorodihydrofluorescein diacetate (DCFH-DA; Beyotime Institute of Biotechnology) to green fluorescent 2' ,7'-dichlorofluorescein (DCF;). DCFH-DA was dissolved in dimethyl sulfoxide to a final concentration of 5 μM. RRPs (1 × 10 6 cells/ml) were incubated with 2 mM DCFH-DA for 20 min under standard conditions, washed three times in PBS and resuspended. The RRPs were assessed with a flow cytometer (FACScan; BD Biosciences) equipped with FACSComp software (Quadra 650) at excitation/emission wavelengths of 488/525 nm.

Astaxanthin Protects Retinal Photoreceptor Cells against High Glucose-Induced Oxidative Stress by Induction of Antioxidant Enzymes via the PI3K/Akt/Nrf2 Pathway

“…Sulforaphane also exhibited similar antioxidative effects in streptozotocin-induced diabetic rats and high glucose-treated Muller cells through the activation of the Nrf2 pathway [54]. Furthermore, activation of Nrf2, either through DJ-1 overexpression [55] or through Nrf2 activators [56], could provide additional benefits to improve retinal pericyte survival and reduce vascular endothelial growth factor-induced cell migration in human retinal microvascular endothelial cells, both involved in the development of DR. In the current study, we have further demonstrated that the Nrf2-ARE pathway can be activated by AST, thereby increasing the expression of HO-1 and NQO1, which in turn attenuates ROS-mediated and intracellular oxidative damage and further protects photoreceptor cells from high glucose-induced apoptosis.…”

Ischemic Postconditioning-Mediated DJ-1 Activation Mitigate Intestinal Mucosa Injury Induced by Myocardial Ischemia Reperfusion in Rats Through Keap1/Nrf2 Pathway

“…DJ-1 overexpression enhanced the expression of Nrf2 and its downstream phase II metabolic enzymes, including HO-1, NQO1, GCLC, and GCLM. In contrast, when Nrf2 was inhibited, even if DJ-1 was overexpressed, the expression of phase II metabolic enzymes was not significantly increased, and rat retinal pericyte apoptosis was not significantly reduced (Wang et al, 2020). Protocatechuic acid protected gastrointestinal mucosa cells against ketoprofeninduced oxidative stress by overexpressing DJ-1/Nrf2, while increased antioxidant enzyme expression could be blocked by si-DJ-1 (Cheng et al, 2019).…”

Effects of neutron radiation on Nrf2‑regulated antioxidant defense systems in rat lens

“…Nrf2 is normally sequestered in the cytoplasm, which can be activated by signals, such as ROS, which subsequently translocates into the nucleus to regulate expression of downstream antioxidant and detoxificationgenes that counteract ROS ( 31 ). These target genes include glutathione peroxidase, SOD, HO-1, quinone oxidoreductase (NQO1) and GCLC ( 4 , 32 ). Activation of the Nrf2 signaling pathway is one of the critical defensive mechanisms against oxidative stress in a number of tissues, including heart, retina, liver and kidney ( 23 ).…”