Free Radical Biology and Medicine最新文献

Resveratrol (Res), a natural polyphenol, is widely used as a functional food additive and food preservative due to its antioxidant and anti-inflammatory properties. However, its protective role against drug-induced organ damage, particularly colistin-induced nephrotoxicity (CIN), remains underexplored. This study investigated Res's protective effects and mechanisms against CIN in rat and NRK-52E cells. In vivo, Res (5-20 mg/kg) significantly improved renal function, alleviated histopathological damage, and restored antioxidant status. Mechanistically, Res modulated the Keap1/Nrf2 axis, suppressing excessive Nrf2 activation and its downstream enzymes. Concurrently, Res inhibited ferroptosis by reducing iron accumulation and modulating key ferroptosis markers (GPX4, ACSL4). In vitro, Res (20 μM) reversed CS- and RSL3-induced cytotoxicity, lipid peroxidation, and ferrous iron overload; Nrf2 siRNA abrogated these effects, confirming Nrf2's essential role. These findings highlight Res as a promising strategy to enhance colistin's clinical safety through precise Nrf2 modulation and ferroptosis inhibition, underscoring the therapeutic potential of natural food compounds.

Prolonged exposure to high altitude (HA) results in a range of systemic changes, some of which, specifically for the heart, particularly cardiac changes, remain difficult to reverse after returning to low altitude. Cardiac de-acclimatization after HA exposure and its underlying mechanisms remain unclear. In this study, mice were subjected to a decompression chamber to simulate a 6000-m altitude exposure for 10 days, followed by the other 10-day de-acclimatization period at a lower altitude of 400 m. The cardiac dysfunction induced by HA exposure persisted throughout the de-acclimatization, accompanied with sustained mitochondrial dysfunction and the short peptide mitochondrial open reading frame of the 12S ribosomal RNA type-c (MOTS-c) deficiency. Exogenous supplementation of MOTS-c during de-acclimatization effectively alleviated the cardiac dysfunction post HA exposure. Mechanistically, MOTS-c activated the PTEN-induced putative kinase 1 (Pink1) / Parkin pathway, promoting mitophagy and improving mitochondrial quality. Silencing Pink1 abolished the protective effects of MOTS-c during de-acclimatization. Additionally, reduced circulating MOTS-c levels were observed in patients with high altitude heart disease and acute coronary syndrome. These results suggest that HA exposure leaves a memory of cardiac dysfunction upon return to lower altitude. This is attributed to a sustained deficiency in MOTS-c. MOTS-c maintains mitochondrial quality through promoting mitophagy, highlighting its therapeutic potential for treating HA-induced cardiac dysfunction during de-acclimatization.

Cyclometallated gold(III) compounds were evaluated for their chemoselective capability to promote C-Se coupling reactions under biocompatible conditions. Competitive reactions with selenium and sulfur substrates highlighted the preference for selenium, and this selectivity was further confirmed in selenopeptide models mimicking the GPx active site. Given that thioredoxin reductase (TXNRD1) is a canonical target for gold compounds, we confirmed that our complexes also inhibit this enzyme, with the two six-membered metallacycles exhibiting a higher potency than auranofin. Expanding beyond TXNRD1, the compounds were further investigated as inhibitors of other selenoenzymes, specifically glutathione peroxidase isoenzymes (GPx1, GPx4). The metallacycles were potent inhibitors of GPx1, while in vitro GPx4 inhibition was overall less pronounced, with LC/MS studies identifying selenocysteine (Sec51) as the primary arylation site on GPx1. We demonstrated that this chemoselectivity could be translated to an intracellular setting. The selectivity towards Se was further explored using A375 GPx4 WT and A375 GPx4 U46C mutant cell lines, where proliferation assays showed a greater effect in the GPx4 WT cells. By integrating structural and functional insights across selenoenzyme families, this study reveals glutathione peroxidases as pivotal molecular targets of cyclometallated gold(III) compounds and lays the groundwork for designing selective Sec-targeting metallodrugs, an approach with untapped potential in anticancer therapy.

Sepsis-induced acute lung injury (ALI) remains a devastatingly lethal clinical syndrome driven by aberrant inflammatory dysregulation, wherein monocytes play critical roles in disease pathogenesis. This study elucidates the mechanistic basis by which the HO-1 inducer Hemin alleviates ALI by activating the HO-1/Nrf2 pathway to target pro-inflammatory monocytes. RNA-seq analysis revealed that the most prominently dysregulated genes in LPS-stimulated human THP-1 monocytes (relative to untreated controls) were predominantly enriched in pathways governing inflammatory responses and oxidative stress. In vitro experiments revealed that Hemin suppressed the p38-MAPK/mTOR pathways in human monocytes, inhibiting inflammatory activation, differentiation, and LPS-induced cell death while preserving phagocytosis. The murine ALI model was established in WT, CCR2^-/-, and Nrf2^-/- mice via tail vein injection of LPS, with assessments conducted 12 hours later. In LPS-challenged mice, Hemin pretreatment selectively inhibited the recruitment of CCR2^hi monocytes (but not CCR2^lo monocytes or neutrophils) into the lungs, thereby attenuating histopathological injury, reducing TNF-α and IL-6 levels, and diminishing monocyte-derived macrophages and their M1/M2 polarization. CCR2 deficiency not only abrogated the therapeutic efficacy of Hemin in ALI, evidenced by the failure to prevent the LPS-induced increase in the proportion of monocyte-derived macrophages and the elevation of macrophage polarization, but also paradoxically elevated pulmonary TNF-α concentrations. Furthermore, experiments using Nrf2^-/- mice revealed that the protective benefits of Hemin are strictly Nrf2-dependent. Nrf2 deficiency prevented Hemin from restoring the redox balance (GSH/GSSG ratio) and abolished its systemic and pulmonary anti-inflammatory effects, along with its suppression of CCR2^hi subsets and inhibition of macrophages polarization. Collectively, our findings establish that activation of the HO-1/Nrf2 pathway mitigates ALI by selectively targeting CCR2^hi pro-inflammatory monocytes, positioning Hemin as a promising therapeutic candidate for ALI and identifying the proportion of CCR2^hi monocyte and Nrf2-mediated redox markers as potential biomarkers to guide precision medicine strategies for ALI management.

Intrauterine adhesion (IUA) is characterized by the formation of endometrial fibrosis within the uterine cavity, which can lead to thin endometrium, hypomenorrhea, infertility, and recurrent abortion, exerting a detrimental impact on women's physical and psychological health. Currently, its pathogenesis is not fully elucidated, absence of effective therapies and coupled with a high recurrence rate. In this study, single-cell RNA sequencing was applied for the first time to a mouse IUA model, revealing significant changes in the expression of senescence markers in endometrial epithelial cells (EECs). Specifically, upregulation of Cdkn1a, and Il6, and downregulation of Lamin B1. Further bioinformatic analysis showed significant enrichment of gene sets related to calcium overload, ER stress, and Endoplasmic Reticulum/Plasma Membrane (ER/PM) contacts in the EECs of IUA mice. Mechanistically, ER/PM contacts in IUA activates the STIM1/Orai1 channel complex, leading to ER stress and intracellular calcium overload, which induces cellular senescence in EECs and ultimately drives IUA progression. Intrauterine administration of the STIM1/Orai1 channel inhibitor BTP2 significantly suppressed ER/PM contacts-induced senescence in EECs and effectively alleviated endometrial fibrosis in the mouse IUA model. In conclusion, targeting the STIM1/Orai1 calcium channel dependent on ER/PM contact sites significantly ameliorates endometrial fibrosis, offering a promising therapeutic strategy for IUA.

Background: D-ribose, a highly reducing pentose sugar, can be phosphorylated by ribokinase (RBKS) to form ribose-5-phosphate (R-5-P). Elevated urinary D-ribose levels have been reported in patients with type 2 diabetes mellitus (T2DM) and Alzheimer's disease, implicating its potential role in disease pathogenesis. Previous investigations into D-ribose cytotoxicity have primarily focused on its non-enzymatic glycation activity, while alternative mechanisms remain underexplored. Since hemoglobin is a major in vivo target of glycation, this study utilized K562 cells-which retain inducible hemoglobin expression-to examine additional cytotoxic mechanisms of D-ribose.

Methods and results: CCK-8 assays demonstrated that D-ribose inhibited K562 cell proliferation in a concentration- and time-dependent manner, and this inhibitory effect was significantly enhanced in hemin-induced differentiated K562 cells. Conversely, RBKS overexpression promoted proliferation and alleviated oxidative stress in K562 cells. Transcriptomic analysis revealed that differentially expressed genes in D-ribose-treated cells were enriched in mineral absorption and oxidative phosphorylation pathways (KEGG), as well as in biological processes related to copper ion homeostasis (GO). RT-qPCR confirmed that both D-ribose treatment and RBKS knockout downregulated key copper homeostasis genes (e.g., SLC31A1, MT1F, ATOX1) and mitochondrial respiratory chain genes (e.g., COX17, COX11, MTATP8, MTND6), and were accompanied by a significant reduction in intracellular free copper levels.

Conclusions: These findings reveal a novel cytotoxic mechanism mediated by the RBKS-copper-oxidative phosphorylation axis in D-ribose-treated K562 cells, providing key insights into the intracellular role of D-ribose.

Objectives: Doxorubicin (Dox) is a potent chemotherapeutic agent whose clinical use is limited by severe cardiotoxicity. The underlying molecular mechanisms remain incompletely understood. This study aimed to investigate the role of the phosphoglycerate mutase 1 (PGAM1)/voltage-dependent anion channel 1 (VDAC1) axis in early-stage Dox-induced cardiotoxicity, focusing on its impact on mitochondrial quality control (MQC), endoplasmic reticulum (ER) stress, and the subsequent activation of innate immune signaling.

Methods: We established a short-term cumulative Dox-induced cardiomyopathy model using wild-type and cardiomyocyte-specific PGAM1 knockout (PGAM1-CKO) mice. Cardiac function was assessed by echocardiography. In vitro experiments were performed on neonatal mouse cardiomyocytes (NMCMs) and HL-1 cells. Molecular techniques including Western blotting, immunofluorescence, co-immunoprecipitation, and quantitative PCR were used to dissect the signaling pathway. Key pathway components were validated using specific pharmacological inhibitors and activators.

Results: Dox treatment significantly upregulated PGAM1 expression in cardiomyocytes. PGAM1-CKO mice were protected from Dox-induced cardiac dysfunction, fibrosis, and inflammation. Mechanistically, Dox-induced PGAM1 promoted the pathological oligomerization of VDAC1. This PGAM1-VDAC1 interaction triggered the collapse of MQC and induced ER stress, leading to the leakage of mitochondrial DNA (mtDNA) into the cytosol. The released cytosolic mtDNA subsequently activated the cGAS-STING innate immune pathway, which we identified as a critical upstream driver of cardiomyocyte ferroptosis. Pharmacological induction of VDAC1 oligomerization or STING activation abolished the cardioprotective effects observed in PGAM1-CKO mice.

Conclusion: Our findings reveal a novel PGAM1/VDAC1 signaling axis that triggers early Dox-induced cardiotoxicity. This axis disrupts mitochondrial homeostasis, leading to mtDNA release, which activates the cGAS-STING pathway and ultimately culminates in cardiomyocyte ferroptosis. Targeting the PGAM1/VDAC1 interaction presents a promising therapeutic strategy to mitigate Dox-induced cardiac injury.

Ambient particulate matter ≤ 2.5 μm in aerodynamic diameter (PM_2.5) is a major environmental carcinogen, yet alterations in the pro-carcinogenic signaling pathways in asymptomatic never smokers remain poorly defined. This study examined the effect of seasonal fluctuations of PM_2.5 on genotoxic stress and pro-oncogenic signaling in rural (RU) and urban (UR) cohorts from West Bengal, India. Environmental monitoring revealed high PM_2.5 and associated benzo[α]pyrene in UR, during winter, induced genotoxic stress in sputum-derived airway cells and peripheral blood mononuclear cells as evidenced from comet assay and 8-hydroxy-2' -deoxyguanosine analysis. RNA sequencing, real-time polymerase chain reaction, indirect enzyme-linked immunosorbent assay and immunoblotting identified activation of the interleukin-6/epidermal growth factor receptor-driven Janus kinase (JAK2)/signal transducer and activator of transcription 3 (STAT3) signaling and associated crosstalk with the rat sarcoma /rapidly accelerated fibrosarcoma /mitogen-activated protein kinase pathways in airway cells and leukocytes of UR cohort. This signaling activation coincided with upregulation of pro-survival effectors (B-cell lymphoma-2, myeloid cell leukemia-1, MYC proto-oncogene, Cyclin D1) and repression of apoptosis regulator, BCL2-associated X, p21 and endogenous JAK/STAT pathway inhibitors (protein inhibitor of activated STAT 2 and suppressor of cytokine signaling 2). Linear mixed-effects regression models linked winter PM_2.5 surges with increased genotoxic damage and altered JAK2/STAT3 cues in UR cohort. Risk modeling further predicted higher PM_2.5-attributed lung cancer mortality in UR populations. Collectively, these findings indicated that elevated PM_2.5 exposure was associated with early genotoxic and JAK2/STAT3-associated pro-carcinogenic alterations in airway cells and leukocytes of asymptomatic individuals, reflecting heightened biological sensitivity in urban populations.

Adolescence represents a vulnerable window for ovarian development, during which oocytes rely heavily on mitochondrial bioenergetics and redox homeostasis. Dibutyl phthalate (DBP) is a widely used plasticizer recognized for its endocrine-disrupting properties. It can compromise oocyte integrity during these sensitive developmental stages. We found that adolescent DBP exposure impairs oocyte quality in mice, causing fragmentation, meiotic arrest, spindle disorganization, and chromosome misalignment. Smart RNA-seq analysis of DBP-exposed oocytes revealed that these defects are associated with mitochondrial dysfunction, particularly impairment of respiratory chain complex I. Consistently, DBP exposure induced mitochondrial clustering, excessive ROS production, loss of membrane potential, ATP depletion, and suppression of complex I activity, which could be recapitulated by in vitro administration of MBP, a bioactive DBP metabolite. Inhibition of complex I with rotenone reduced oocyte maturation and mitochondrial membrane potential, supporting complex I as a primary target of DBP-induced injury. Mechanistically, DBP reduced 5-taurinomethyluridine (τm⁵U) modification of mitochondrial tRNAs and decreased the protein level of the mitochondrially encoded complex I subunit MT-ND1, leading to impaired complex I activity. Systemic taurine availability was also reduced. Notably, taurine supplementation restored τm⁵U modification and enhanced MT-ND1 translation, thereby rescuing complex I activity and reestablishing mitochondrial function. These improvements mitigated DNA damage and apoptosis, corrected meiotic defects, and rescued oocyte maturation, embryonic development, and fertility. Together, our findings indicate that DBP disrupts oocyte development by impairing mitochondrial redox homeostasis in mice, and suggest that taurine supplementation can restore mitochondrial function and preserve female fertility under environmental insults.

Acute hyperbaric stress during diving combines increased ambient pressure, hyperoxia, hemodynamic shifts, and often muscular workload. Identifying real-time blood biomarkers sensitive to these individual and combined physiological loads remains a challenge. Neuregulin-4 (NRG4), an adipokine secreted by thermogenic and subcutaneous white fat, responds to adrenergic stimulation and modulates redox homeostasis. We investigated NRG4 dynamics alongside oxidative protein carbonyls in divers in warm (thermoneutral) water (∼33.6 °C ambient water temperature) to avoid cold stress. Two field campaigns were conducted: a first depth response campaign involved divers exposed to 20, 30, or 40 m on separate days, without exercise, with serial blood sampling; a second physical effort study involved 15 m dives with or without slow-pedalling exercise. Serum NRG4 was quantified by ELISA and expressed as log₂ fold change relative to baseline. Protein carbonyls were measured as markers of oxidative damage. Statistical analysis employed single-sample tests and false-discovery rate control. NRG4 exhibited a robust early increase at 30 m, significant after correction, and nominal elevations at 40 m, but remained unchanged at 20 m. Exercise at 15 m triggered a significant early NRG4 rise absent during passive dives at the same depth. Protein carbonyls remained stable in early post-emersion windows but increased significantly at later time points (180- and 240-min post-emersion) following dives to 40 m, indicating delayed oxidative burden. Our findings position NRG4 as a fast, pressure- and workload-responsive biomarker of diving stress, temporally distinct from classical oxidative injury markers that manifest later. This temporal dissociation underscores the potential of NRG4 for real-time monitoring of acute physiological load during hyperbaric exposure, integrating pressure- and workload-related stressors.