Redox Report最新文献

Background: Mitochondrial division is one of the main characteristics for the initiation of myogenic differentiation. However, the role and mechanism of Dynamin-related protein 1 (Drp1), the most important protein that regulates mitochondrial fission in mammals, in regulating myogenic differentiation are not well understood.

Methods: Drp1 siRNAs were transfected to C2C12 cells, or AAV9-shDrp1 were injected to C57BL/6J mice to knockdown Drp1 expression. Then, mitochondrial damage, ROS level, myogenic differentiation, mitophagy and actin/MRTF-A/SRF pathway was detected by quantitative real-time PCR, western blotting, immunofluorescence staining and flow cytometry.

Results: The results showed that Drp1 was upregulated after C2C12 differentiation; Drp1 knockdown by siRNA transfection impaired myotube formation. ROS are the upstream activators for Drp1 expression, and Drp1 inversely reduces ROS by facilitating mitophagy to form a ROS-Drp1-mitophagy feedback loop during myogenic differentiation. Knockdown of Drp1 disrupted the ROS-Drp1-mitophagy feedback loop-mediated ROS homeostasis, thereby accelerating F-action depolymerization and blocking MRTF-A nuclear translocation by reducing the phosphorylation of cofilin. A decrease in MRTF-A nuclear translocation impaired SRF activity and hindered myogenic differentiation.

Conclusion: In summary, this study revealed the functional mechanism of Drp1 and clarified the interactions among ROS, Drp1-mediated mitophagy and actin cytoskeleton remodeling during myogenic differentiation.

Background: Iron continues to be linked to the pathogenesis of neurodegenerative disorders including HIV-1 associated neurocognitive disorders (HAND). People with HIV-1 who use opioids have a higher risk of developing HAND, and HIV-1 proteins and opioids disrupt endolysosome iron homeostasis, increase reactive oxygen species (ROS), and cause neural cell death. Endolysosomes are subcellular acidic organelles that regulate iron metabolism and redox homeostasis. HIV-1 gp120 and opioids induce endolysosome iron release, increasing cytosolic and in mitochondrial iron and ROS and inducing neurotoxicity. However, ROS represent only part of the reactive species interactome (RSI) and little is known about the extent to which HIV-1 proteins and opioids affect the RSI.

Results: In SH-SY5Y and U87MG cells, HIV-1 gp120, morphine, and iron supplementation de-acidified endolysosomes, decreased endolysosome Fe²⁺ and H₂S, and increased ROS, lipid peroxidation (LPO) and NO. These changes were accompanied by increased cytosolic and mitochondrial Fe²⁺, ROS, LPO, and NO, decreased H₂S, and increased cell death. All effects were blocked by the endolysosome-specific iron chelator deferoxamine.

Conclusion: Endolysosome iron dyshomeostasis induced by HIV-1 gp120, morphine and iron supplementation disrupts inter-organellar iron signaling and RSI homeostasis. Targeting endolysosome iron may mitigate neurotoxicity in HAND and other disorders associated with iron overload and redox imbalance.

Selenium (Se) is linked to physiological homeostasis. Male mice (n = 8/group) were fed control (AIN93G) or diets enriched in sodium selenite (NaSe, 5.6 ppm), methylselenocysteine (Met, 4.7 ppm), diphenyl diselenide (DPDS, 14.2 ppm), or nanoselenium (NanoSe, 2.7 ppm); dietary Se ascertained by inductively-coupled plasma mass spectrometry. At 4 weeks testes, sperm, thyroids, blood and stool were collected to assess histoarchitecture, circulating hormones (thyroxine, T4; triiodothyronine, T3; thyroid stimulating hormone, TSH) and gut microbiome (16S rRNAV3-V4 amplicon sequencing). Supplemented NaSe, Met, and NanoSe increased plasma testosterone and testis glutathione peroxidases (GPx-1/4) while testicular superoxide dismutase and catalase increased slightly in the NanoSe group indicating a selective antioxidant response. Overall, NanoSe and NaSe enhanced male reproductive factors. All thyroids isolated from Se-supplemented mice contained marginal vacuoles and a lower follicle area vs control. Nano-Se enhanced thyroidiodothyronine deiodinase-1 (DIO1) expression however, thyroid GPx-1/4 remained unchanged. Supplemented NaSe and DPDSl increased plasma T3/T4 ratio, while plasma TSH was unchanged. Microbiome analyses showed that NanoSe was most efficacious in altering composition (judged by α-diversity, Shannon index and taxon richness) while the NaSe diet showed the greatest overall change in α-diversity. Dietary Se supplementation, particularly encapsulated NanoSe, may improve male fertility factors by enhancing the gut-thyroid-fertility axis.

Renal fibrosis is a key factor in the progression of chronic kidney disease (CKD), and current treatments remain inadequate. In this study, we investigated the therapeutic effects of cynaroside (Cyn), a natural flavonoid, in a mouse model of renal fibrosis induced by unilateral ureteral obstruction. Cyn treatment significantly ameliorated tubular injury and interstitial fibrosis while improving renal function. Mechanistically, Cyn inhibited the expression of fibrosis-related proteins and suppressed Smad2/3 phosphorylation. Additionally, Cyn reduced myofibroblast accumulation by inhibiting epithelial-mesenchymal transition, as indicated by increased E-cadherin expression and decreased levels of mesenchymal markers. Cyn also reduced oxidative stress by downregulating the prooxidant enzyme NADPH oxidase 4 and restoring antioxidant enzymes. Furthermore, Cyn attenuated ferroptosis by regulating key proteins, including acyl-CoA synthetase long-chain family member 4, transferrin receptor 1, and glutathione peroxidase 4, while also restoring glutathione levels. Cyn alleviated endoplasmic reticulum stress, as evidenced by the downregulation of key markers such as glucose-regulated protein 78 and activating transcription factor 6, and reduced inflammation, as confirmed by decreased macrophage infiltration and lower cytokine production. Overall, Cyn demonstrated broad protective effects against renal fibrosis by modulating oxidative stress, ferroptosis, ER stress, and inflammation, positioning it as a potential therapeutic agent for CKD management.

Inflammation is associated with a wide range of medical conditions, most leading causes of death, and high healthcare costs. It can thus benefit from new insights. Here we extended previous studies and found that oxidation of human native mtRNA to 'mitoxRNA' strongly potentiated IFNβ and TNFα immunostimulation in human cells, and that this newly identified type 1 interferon potentiation was transcriptional. This potentiation was significantly greater than with mtDNA oxidation, and t-butylhydroperoxide (tBHP) oxidation of RNA was more proinflammatory than hydrogen peroxide (HP). mtRNA triggered a modest increase in apoptosis that was not potentiated by oxidation, and mtDNA triggered a much greater increase. For native mtRNA, we found that chloroquine-inhibitable endosomes and MDA5 are key signaling pathways for IFNβ and TNFα production. For mitoxRNAs, RNAseq revealed a major increase in both tBHP- and HP-mitoxRNA modulated genes compared with native mtRNA. This increase was very prominent for interferon-related genes, identifying them as important mediators of this powerful oxidation effect. Moderately different gene modulations and KEGG pathways were observed for tBHP- versus HP-mitoxRNAs. These studies reveal the profound effect that mitochondrial RNA oxidation has on immunostimulation, providing new insights into DAMP inflammation and identifying potential therapeutic targets to minimize DAMP mtRNA/mitoxRNA-mediated inflammation.

Background: Diabetic nephropathy (DN) is the most common complication of diabetes mellitus. It has shown that the activation of nuclear factor erythroid 2-related factor 2 (Nrf2) could attenuate DN. To identifiy novel Nrf2 activators targeting DN, we explored drynachromoside A (DCSA) from Drynaria fortunei in vitro and in vivo.

Methods: To determine the effects of DCSA, the proliferation of mesangial cells induced by high glucose was evaluated. And the renal function of db/db mice was evaluated. Meanwhile, oxidative stress and renal fibrosis in vitro and in vivo were further investigated. To elucidate the mechanism of DCSA, Nrf2 activation and its role in these effects were explored, and the interaction between Kelch-like ECH-associated protein 1 (Keap1) and DCSA was examined.

Results: DCSA inhibited the proliferation of mesangial cells resulting from high glucose and improved renal function in db/db mice. DCSA attenuated oxidative stress and fibrosis in vitro and in vivo, which was closely associated with Nrf2 activation in a Keap1-dependent manner.

Conclusion: DCSA identified in Drynaria fortunei is a Keap1-dependent Nrf2 activator with the potential to attenuate DN. This investigation could provide novel insights into the discovery of Nrf2 activators and new therapeutic approaches for DN.

Objectives: Osteoporosis, a prevalent metabolic bone disease affecting millions worldwide. Although MS-275 has been reported to inhibit oxidative stress, its ability to protect osteoblasts from oxidative stress damage has yet to be clarified. This study investigated whether MS-275 can inhibit oxidative stress and promote osteogenesis by activating the miRNA-200a/Keap1/Nrf2 signaling pathway.

Methods: In vitro, MC3T3-E1 cells underwent induction with carbonyl cyanide 3-chlorophenylhydrazone, leading to the establishment of an oxidative stress model, investigating the underlying mechanism. In vivo, using a rat model of ovariectomized osteoporosis, evaluating the effects of MS-275.

Results: In vitro, MS-275 treatment of oxidation-induced MC3T3-E1 cells resulted in up-regulation of osteoblast protein, increased expression of miRNA-200a, increased binding of miRNA-200a to Keap1 mRNA, decreased expression of Keap1 protein, and dissociation of Nrf2 from Keap1. The expressions of total Nrf2, nuclear Nrf2 and HO-1 were increased, mitochondrial function was enhanced, and oxidative damage was reduced. However, these effects were reversed after interference with miRNA-200a. In vivo,MS-275 effectively enhanced the microstructural features of distal femoral trabecular bone, increased the mineralization capacity of osteoblasts, and promoted bone formation.

Discussion: MS-275 can reverse oxidative stress-induced cell damage, promote bone healing, and improve osteoporosis by activating the miRNA-200a/Keap1/Nrf2 pathway.

Objective: Inflammation and oxidative damage play critical roles in the pathogenesis of sepsis-induced cardiac dysfunction. Multiple EGF-like domains 9 (MEGF9) is essential for cell homeostasis; however, its role and mechanism in sepsis-induced cardiac injury and impairment remain unclear.

Methods: Adenoviral and adeno-associated viral vectors were applied to overexpress or knock down the expression of MEGF9 in vivo and in vitro. To stimulate septic injury, cardiomyocytes and mice were treated lipopolysaccharide (LPS). To clarify the necessity of AMP-activated protein kinase (AMPK), global AMPK knockout mice were used.

Results: We found that MEGF9 expressions were reduced in cardiomyocytes and mice by LPS stimulation. Compared with negative controls, plasma MEGF9 levels were also decreased in septic patients, and negatively correlated with LPS-induced cardiac dysfunction. In addition, MEGF9 overexpression attenuated, while MEGF9 knockdown aggravated LPS-induced inflammation and oxidative damage in vivo and in vitro, thereby regulating LPS-induced cardiac injury and impairment. Mechanistic studies revealed that MEGF9 overexpression alleviated LPS-induced cardiac dysfunction through activating AMPK pathway.

Conclusion: We for the first time demonstrate that MEGF9 prevents LPS-related inflammation, oxidative damage and cardiac injury through activating AMPK pathway, and provide a proof-of-concept for the treatment of LPS-induced cardiac dysfunction by targeting MEGF9.

Background: Regenerative medicine researches have shown that mesenchymal stem cells (MSCs) may be an effective treatment method for premature ovarian insufficiency (POI). However, the efficacy of MSCs is still limited.

Purpose: This study aims to explain whether salidroside and MSCs combination is a therapeutic strategy to POI and to explore salidroside-enhanced MSCs inhibiting ferroptosis via Keap1/Nrf2/GPX4 signaling.

Methods: The effect of salidroside and MSCs on ovarian granular cells (GCs) was analyzed. After treatment, hormone levels and -fertility of rats were measured. Lipid peroxidation levels, iron deposition and mitochondrial morphology were detected. The genes and proteins of Keap1/Nrf2/GPX4 signaling were examined.

Results: Salidroside and MSCs were found to inhibit cell death of GCs by reducing peroxidation and intracellular ferrous. Salidroside promotes the proliferation of MSCs and supports cell survival in ovary. Salidroside combined with MSCs therapy restored ovarian function, which was better than MSCs monotherapy. Salidroside-enhanced MSCs to inhibit ferroptosis. The results showed activation of the Keap1/Nrf2/GPX4 signaling and an increase in anti-ferroptosis molecule.

Conclusions: Salidroside-enhanced MSCs as a ferroptosis inhibitor and provide new therapeutic strategies for POI. The possible mechanisms of MSCs were related to maintaining redox homeostasis via a Keap1/Nrf2/GPX4 signaling.

Background: Amiodarone, a common antiarrhythmic drug, is known for its severe side effects, including pulmonary toxicity, which involves oxidative stress and apoptosis. Artemisinin, an antimalarial drug, has shown cytoprotective properties by inhibiting oxidative stress and apoptosis. This study investigated the protective effects of artemisinin against amiodarone-induced toxicity in human bronchial epithelial cells (BEAS-2B) and mouse models.

Results: In vitro experiments revealed that amiodarone decreased cell viability, increased LDH release, ROS generation, caspase 3 activation, and apoptosis in BEAS-2B cells. Artemisinin counteracted these effects by upregulating p-AMPK, CaMKK2, Nrf2, and SOD1 protein levels, thereby protecting the cells from oxidative damage. The protective effect of artemisinin was diminished by the AMPK inhibitor Compound C or AMPKα knockdown. In vivo experiments demonstrated that artemisinin increased p-AMPK and Nrf2 protein levels in lung tissues, protecting against amiodarone-induced apoptosis and bronchial epithelial cell shedding in mice.

Conclusion: These findings suggest that artemisinin protects airway epithelial cells and lung tissue from amiodarone-induced oxidative stress and apoptosis through AMPK activation, offering potential new strategies for preventing and treating amiodarone-induced pulmonary toxicity.