Redox Report最新文献

Objectives: The study aimed to investigate the signalling mechanism for TRPM2 channel activation by non-cytolytic oxidative stress in microglia.

Methods: Microglia from wild-type (WT) and TRPM2-knockout (KO) mice were exposed to 10-30 mM H₂O₂ for up to 24 hours. Morphological changes characteristic of microglial activation, [Ca²⁺]_c, ROS generation and the effects of inhibiting particular signalling pathways were examined.

Results: Exposure of WT microglia to H₂O₂ for 24 hours caused no cell death but induced salient morphological changes, which was prevented by TRPM2-KO. Exposure of WT microglia to H₂O₂ to 2 hours failed, and extension to 8 hours was required, to induce an increase in [Ca²⁺]_c, which was abolished by TRPM2-KO. Exposure of microglia to H₂O₂ for 8 hours induced ROS generation, which was suppressed by inhibition of PKC and NADPH oxidases (NOX). H₂O₂-induced PARP activation in TRPM2-KO cells was lower than that in WT cells. Furthermore, H₂O₂-induced activation of PARP and TRPM2 and morphological changes were attenuated by inhibition of PCK and NOX as well as PYK2 and MEK/ERK.

Conclusion: Our results support that PKC/NOX-mediated ROS generation and TRPM2-mediated Ca²⁺-induced activation of the PYK2/MEK/ERK pathway form a positive feedback mechanism to drive TRPM2 channel activation by non-cytolytic oxidative stress.

Friedreich's Ataxia (FRDA) is a rare neurological disorder caused by an abnormal expansion of Guanine-Adenine-Adenine (GAA) repeat in intron 1 of the FXN gene, which encodes frataxin, leading to reduced expression of frataxin, a mitochondrial protein essential for cellular homeostasis. Frataxin deficiency results in oxidative stress and mitochondrial dysfunction and impaired redox balance. Currently, there is no cure for FRDA. This study aimed to evaluate the therapeutic potential of antioxidants dimethyl fumarate (DMF), N-acetylcysteine (NAC), and L-ascorbic acid (LAA) in restoring mitochondrial redox homeostasis and frataxin levels in FRDA patient-derived fibroblasts and 2D sensory neurons. We assessed cell viability, mitochondrial and cellular reactive oxygen species (ROS) levels, mitochondrial DNA copy number, mitochondrial membrane potential, and frataxin and NRF2 expression at both mRNA and protein levels following antioxidant treatment, either individually or in combination. Treatment with LAA, NAC, and DMF resulted in significant reductions in mitochondrial and cellular ROS, along with increased FXN and NRF2 expression, and enhanced NRF2 nuclear translocation. Furthermore, these compounds improved aconitase/citrate synthase activity, GSH/GSSG ratios, and mitochondrial membrane potential. Notably, the combination of LAA and NAC consistently alleviated multiple disease-associated defects in FRDA cells, suggesting its potential as a promising therapeutic approach.

Objectives: Cerebral ischemic stroke is a leading cause of death worldwide. Though timely reperfusion reduces the infarction size, it exacerbates neuronal apoptosis due to oxidative stress. Nuclear factor erythroid 2-related factor 2 (Nrf2) is a transcription factor regulating the expression of antioxidant enzymes. Activating Nrf2 gives a therapeutic approach to ischemic stroke.

Methods: Herein we explored flavonoids identified from Polypodium hastatum as Nrf2 activators and their protective effects on PC12 cells injured by oxygen and glucose deprivation/restoration (OGD/R) as well as middle cerebral artery occlusion (MCAO) mice.

Results: The results showed among these flavonoids, AAKR significantly improved the survival of PC12 cells induced by OGD/R and activated Nrf2 in a Keap1-dependent manner. Further investigations have disclosed AAKR attenuated oxidative stress, mitochondrial dysfunction and following apoptosis resulting from OGD/R. Meanwhile, activation of Nrf2 by AAKR was involved in the protective effects. Finally, it was found that AAKR could protect MCAO mice brains against ischemia/reperfusion injury via activating Nrf2.

Discussion: This investigation could provide lead compounds for the discovery of novel Nrf2 activators targeting ischemia/reperfusion injury.

Background: Diabetic nephropathy (DN) drives progressive renal fibrosis and functional decline, ultimately leading to end-stage renal disease. Pathological crosstalk between glomerular endothelial cells and mesangial cells is increasingly recognized as central to DN progression. However, whether endothelial-derived signaling specifically drives mesangial injury under diabetic conditions remains undefined.

Methods: We applied multi-omics profiling to identify pathogenic drivers. Target validation included qPCR and immunofluorescence co-localization in renal tissues. In vitro endothelial-mesangial crosstalk was modeled using conditioned media (CM) from mouse GECs applied to mesangial cells. Verbascoside (VB) was screened via structure-based virtual docking against LOX/LOXL2 and binding affinity (KD) confirmed by biolayer interferometry (BLI). In vivo therapeutic efficacy of VB was assessed in db/db mice.

Results: LOX/LOXL2 was robustly upregulated in diabetic endothelia. Inhibiting endothelial-derived LOX/LOXL2 or HIF-1α in GECs attenuated HG-induced mesangial dysfunction by reducing proliferation/viability, oxidative stress, and fibrosis. Mechanistically, HIF-1α drove LOX/LOXL2 expression. VB was identified as a novel dual LOX/LOXL2 inhibitor. VB-CM mitigated mesangial injury in vitro. VB treatment improved renal function, reduced oxidative damage, and ameliorated fibrosis.

Conclusion: Endothelial HIF-1α/LOX signaling drives mesangial oxidative stress and fibrosis in DN. Verbascoside, a dual LOX/LOXL2 inhibitor, represents a promising therapeutic agent targeting this pathogenic axis.

Background: Inflammatory pain is the most common type of chronic pain, and it is rapidly becoming a global health problem. Ginkgo biloba (EGb761) is a natural plant that contains several bioactive components with antioxidant and free radical scavenging properties. However, its underlying mechanism in inflammatory pain remains unclear. The aim of this study was to assess the effects and mechanisms of EGb761 on a complete Freund's adjuvant (CFA)-induced inflammatory pain model in rats.Methods: A single dose of CFA was subcutaneously injected into the right hind paws of the rats, after which EGb761 (100 mg/kg/day) was orally administered for 14 days.Results: Oral EGb761 markedly decreased hind paw edema in CFA-treated rats. In addition, EGb761 significantly reduced thermal hyperalgesia by increasing the hot plate latency and improved motor coordination. Notably, EGb761 significantly reduced nitric oxide levels and catalase enzyme activity in the lumbar spinal cord (LSPC) of CFA-treated rats. Furthermore, EGb761 inhibited the mRNA expression of NF-ĸB, CXCL1, and CXCR2. At the histological level, EGb761 prevented CFA-induced tissue and neuronal damage in the LSPC dorsal horn. The immunohistochemical analysis revealed that caspase-3 levels were significantly reduced, whereas Bcl-2 expression was insignificantly increased with EGb761 treatment in rats with CFA-induced inflammation.Conclusion: EGb761 alleviated CFA-induced chronic inflammatory pain by attenuating oxidant-antioxidant dysregulation, blocking the NF-κB-CXCL1/CXCR2 inflammatory axis, and counteracting neural cell apoptosis in the LSPC. Our results suggest that EGb761 can be used as an analgesic for the treatment of pain associated with inflammation and tissue injury.

Spermidine (SPD) is an organic compound known for its powerful antioxidant stress and anti-aging properties, and whether SPD has the ability to reduce bone mass in elderly iron overload rats is unknown. The study aimed to assess SPD's impact on iron overload-induced bone loss in elderly rats. In our aged rat model, we found that iron overload negatively influences bone metabolism and remodeling, resulting in decreased bone mineral density and increased bone loss. However, SPD treatment effectively alleviated these harmful effects, as shown by reduced serum levels of MDA and increased SOD and GSH levels. Additionally, SPD-treated rats exhibited enhanced bone mass and higher expression of OC, BMP2, SIRT1, and SOD2 in their bones. Moreover, SPD restored the imbalance in bone metabolism by counteracting the inhibition of osteogenic differentiation and promoting osteoclast differentiation induced by iron overload in MC3T3-E1 and RAW264.7 cells affected by EX527. In summary, our findings suggest that SPD's antioxidant properties may exert anti-osteoporosis effects through activation of the SIRT1/SOD2 signaling pathway.

Background: Sympathetic overactivity is closely associated with vascular remodeling. Sympathetic fibers dominantly innervate the adventitia of arteries rather than tunica media. Vascular adventitial fibroblasts (VAFs) play crucial roles in vascular remodeling. However, the link between sympathetic overactivity and VAF proliferation and migration is unknown.

Methods: Primary VAFs were isolated from the thoracic aorta of spontaneously hypertensive rats and Wistar-Kyoto rats. Norepinephrine (NE) bitartrate monohydrate was applied to VAFs to simulate the sympathetic overactivity.

Results: NE increased NADPH oxidase (NOX) 2 expression and superoxide level, which were almost abolished by NOX2 inhibitor GSK2795039 or α-adrenoceptor antagonist prazosin, but not significantly affected by NOX1 inhibitor ML171, NOX4 inhibitor GLX351322 or β-adrenoceptor antagonist propranolol. Superoxide scavenger tempol or NOX2 inhibitor GSK2795039 attenuated NE-induced VAF proliferation and migration. NE promoted protein kinase C (PKC) phosphorylation and NFκB-p65 nuclear translocation. Either PKC inhibitor Go6983 or NFκB inhibitor BAY11-7082 attenuated NE-induced NOX activation, NOX2 upregulation, superoxide production, proliferation and migration.

Conclusion: NE promotes oxidative stress by α-receptor/PKC/NFκB-mediated NOX2 upregulation, which contributes to proliferation and migration of VAFs.

Background: Alopecia is a global dermatological challenge. Adipose-derived stem cells (ADSC) show therapeutic potential, but their mechanisms in promoting hair regrowth, particularly under oxidative stress conditions, remain unclear..

Objective: To investigate ADSC's role in promoting hair regrowth by mitigating oxidative stress.

Methods: Using H₂O₂-stressed HaCaT cells, ADSC's protective effects were evaluated via conditioned medium (CM) and co-culture. Assessments included cell viability, colony formation, ROS, MDA, antioxidant enzymes, and 8-OHdG. Nrf2 activation was analyzed by immunofluorescence and Western blot. A mouse radiation injury model validated findings.

Results: Non-pretreated ADSC offered limited oxidative protection to HaCaT cells. Conversely, H₂O₂-pretreated ADSC significantly enhanced HaCaT viability and proliferation in both CM and co-culture systems. This involved paracrine activation of the Nrf2 pathway in HaCaT cells, boosting antioxidant enzymes, accelerating ROS clearance, and reducing lipid peroxidation. These effects were reversible with Nrf2 inhibition. In vivo, CM from H₂O₂-stimulated ADSC promoted hair regrowth in irradiated mice, outperforming CM from non-pretreated ADSC by activating Nrf2 and reducing tissue oxidative damage.

Conclusions: Oxidative stress potentiates the protective capacity of ADSC against oxidative via Nrf2-dependent paracrine mechanisms, offering a promising strategy for alopecia treatment.

Heatstroke (HS)-induced acute lung injury (ALI) has high morbidity and mortality with no specific therapies. Ferroptosis, a form of programmed cell death driven by lipid peroxidation due to reduced Glutathione Peroxidase 4 (GPX4) activity, is closely linked to HS-induced ALI. This study investigated the effect of alpha-linolenic acid (ALA), a plant-derived ω-3 fatty acid, on ferroptosis in a mouse model of HS-induced ALI. Histopathology analysis found that ALA can attenuate lung injury and improve the 7-day survival rate in mice with HS-induced ALI. In addition, ALA significantly reduced the levels of reactive oxygen species (ROS) and malondialdehyde (MDA), while increasing the level of antioxidant glutathione (GSH). Further analysis showed that ALA upregulated the levels of SLC7A11 and GPX4 by promoting the nuclear translocation of Nrf2. This led to increased GSH synthesis but reduced ROS accumulation, which in turn suppressed ferroptosis and protected the mice against HS-induced ALI. Additionally, the protective effect of ALA was found to be diminished in Nrf2-deficient mice. In summary, ALA inhibits ferroptosis in macrophages by activating the Nrf2/SLC7A11/GPX4 pathway and attenuates HS-induced ALI.

Background: The adaptation of the redox system and bioenergetics is a major factor contributing to cancer metabolism. Redox therapy is promising but still requires molecular studies that consider the reactive species interactome (RSI) concept, which integrates reactive oxygen, nitrogen, sulfur, carbonyl species, and redox enzymes. Our aim was to decipher the role of the RSI in glioblastoma (GBM), including by challenging the RSI with the MnTBAP redox agent.

Methods: The effects of MnTBAP on the redox system and bioenergetics were investigated on several GBM models, namely in vitro 2D culture, in vitro 3D culture with two human GBM tumoroids, and in vivo preclinical model, which included male and female comparisons.

Results: We show - for the first time - that MnTBAP represses the sulfide:quinone oxidoreductase (SQOR) involved in the sulfur metabolism and bioenergetics, and targets the RSI through the sulfido-redox system. Through in vitro silencing and overexpression approaches, we also demonstrate that SQOR contributed to GBM cell growth and that its decrease is involved in the molecular effect of MnTBAP. Consequently, MnTBAP induces a switch between apoptosis, uncontrolled necrosis, and ferroptosis depending on the glioblastoma models.

Conclusion: Our findings represent the next step in establishing a better understanding of redox biology in the context of GBM.