Free Radical Biology and Medicine最新文献

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.

Adults of Schistosoma mansoni reside in the mesenteric veins, where they are naturally exposed to high levels of hydrogen sulfide (H₂S). S. mansoni and other intestinal parasites have adapted to this sulfide-rich environment, but the evolved mechanisms to metabolize sulfide remain unelucidated. Here we reveal that the putative sulfide:quinone oxidoreductase (SQOR) encoded by S. mansoni is indeed an SQOR, catalyzing the first step of sulfide metabolism. We demonstrated that S. mansoni SQOR (SmSQOR) is expressed in eggs, cercaria and adult stages and localized in the mitochondria. The reaction catalyzed by SmSQOR was investigated using sulfane sulfur probe 4 (SSP4) and shown to require the co-presence of sulfide, quinone, and a sulfur acceptor, indicating a quaternary complex-mediated mechanism. Unlike human and bacterial SQORs, purified SmSQOR could not reduce quinones in the presence of sulfide alone unless sulfite, cyanide, or L-cysteine (but not coenzyme A or glutathione) was provided as the sulfur acceptor. In the presence of these sulfur acceptors, SmSQOR formed a long-lived charge-transfer (CT) complex, a transient electronically coupled association between electron donor and acceptor, as indicated by a broad band around 637-755 nm in the spectrum, which was associated with a partial loss of enzyme activity. Moreover, residues critical for CT complex formation and SQOR catalysis were identified. Using SSP4, we also demonstrated that SQOR was active in S. mansoni adult, egg, and cercaria stages. Taken together, these features suggest that metabolism of sulfide proceeds differently in S. mansoni than in humans.

Small cell lung cancer (SCLC) is an aggressive malignancy characterized by limited therapeutic options. In this study, we identified GL-V9 as a potent anti-SCLC agent that induces apoptosis through oxidative stress. GL-V9 significantly reduced SCLC cell viability in a dose-dependent manner and triggered apoptosis both in vitro and in xenograft models. Mechanistically, GL-V9 increased reactive oxygen species (ROS) levels and lipid peroxidation while impairing mitochondrial function, suggesting that its cytotoxic effects are mediated by oxidative stress. Drug-target interaction analyses revealed that GL-V9 directly binds to STEAP3, a key regulator of iron metabolism, and promotes its degradation via the ubiquitin-proteasome pathway. The loss of STEAP3 disrupted iron homeostasis and exacerbated oxidative stress. In contrast, STEAP3 overexpression attenuated ROS accumulation, mitochondrial damage, and apoptosis both in vitro and in vivo. Further investigation demonstrated that STEAP3 degradation decreased the stability of CISD2, a [2Fe-2S] cluster-containing mitochondrial protein essential for redox balance. GL-V9 downregulated CISD2 in a STEAP3-dependent manner, and restoring CISD2 expression significantly rescued cells from GL-V9-induced oxidative stress and apoptosis. Clinically, both STEAP3 and CISD2 are upregulated in SCLC tumors, and their elevated expression correlates with poor patient survival. Co-expression analysis associated these proteins with pathways involved in oxidative stress and mitochondrial dysfunction. Overall, these findings suggest that GL-V9 induces apoptosis in SCLC by targeting STEAP3 for proteasomal degradation, thereby disrupting the STEAP3-CISD2 axis and promoting oxidative stress-driven cell death. This study identifies a previously unrecognized redox regulatory pathway in SCLC and proposes a potential therapeutic strategy centered on selective induction of oxidative stress.

The distinctive characteristics of diabetic cardiomyopathy (DCM), a serious outcome of diabetes mellitus, are anomalies in the structure and functionality of the cardiac tissue. With a focus on their impact on inflammatory responses, oxidative injury, and the functioning of metabolic enzymes, this investigation aimed to evaluate the cardioprotective benefits of inulin and cichoriin over diabetes-related cardiomyopathy induced by high fat diet-streptozotocin (HFD-STZ) in mice. Diabetes was introduced in male Swiss albino mice by feeding them a high-fat diet followed by STZ injection and treated with cichoriin (50 and 100 mg/kg) or inulin (200 and 400 mg/kg). Serum biochemical, lipid, and cardiac injury markers were estimated. The metabolic enzyme activity (G6Pase, FBPase, ATPase, ENTPDase, 5'NT), oxidative stress markers (SOD, CAT, GSH, MDA, LDH), Angiotensin-Converting Enzyme (ACE) activity, and histological changes in the heart, pancreas, liver, and kidney, were assessed. NF-κB and Nrf2 immunohistochemistry was used to evaluate inflammatory and oxidative signalling. Treatment with inulin and cichoriin, especially at higher dosages, improved ACE activity, normalized metabolic enzyme activities, and substantially restored antioxidant enzyme levels. They reduced hyperglycemia, body weight loss, hyperlipidemia, and heart dysfunction with histological changes and fibrosis brought on by diabetes. Alongside these effects, cardiac tissues showed increased Nrf2 expression and decreased NF-κB, indicating the return of redox equilibrium and myocardial integrity. Thus, cichoriin and inulin substantially ameliorate the DCM by reducing oxidative injury, controlling glucose metabolism, and altering NF-κB/Nrf2 signaling pathways. These results demonstrate their potential for use as natural cardioprotective agents in the treatment of diabetic cardiomyopathy.

The accumulation of amyloid-beta (Aβ₄₂) plaques is a hallmark of Alzheimer's disease (AD), which currently have no cure. The 3-deoxyanthocyanidins (3-DXA) and their derivatives represent a more stable class of polyphenols, identified in sorghum grains at uniquely high concentrations. Although 3-DXA exhibit strong potential to modulate protein aggregation processes, their effects on AD pathology remain largely unexplored. In this study, we investigated the inhibitory effects of three 3-DXA derivatives apigeninidin chloride (AC), luteolinidin chloride (LC), and 7-methoxy apigeninidin (7-MAC) on Aβ₄₂ aggregation and associated neurotoxicity. Thioflavin T (ThT) fluorescence assay was employed to assess alterations in Aβ₄₂ aggregation, while circular dichroism and nuclear magnetic resonance spectroscopy were used to evaluate changes in secondary structure. The neuroprotective effects of the 3-DXA derivatives were further examined in MC-65 cells under Aβ-induced toxicity. Additionally, generalized replica exchange with solute tempering based molecular dynamics simulations was conducted to explore the effects of AC and LC on Aβ₄₂ dimer stability and β-sheet disruption. Our findings demonstrate that AC, LC, and 7-MAC significantly reduced Aβ₄₂ aggregation by up to 88%, with AC and LC showing particularly strong disruption of β-sheet structures. All three compounds significantly rescued MC-65 cells from Aβ₄₂-induced toxicity (62-77%) and enhanced mitochondrial activity. Molecular dynamics simulations analyses revealed that AC and LC disrupted hydrophobic interactions within Aβ₄₂ dimers, contributing to destabilisation of neurotoxic aggregates. Overall, AC and LC exhibited strong multitarget activity against AD pathology by inhibiting Aβ42 aggregation, restoring intracellular energy balance, and disrupting key neurotoxic structural motifs.

Introduction: Doxorubicin (DOX) is a widely used chemotherapeutic agent, but its clinical application is limited by dose-dependent cardiotoxicity. Currently, there are no effective strategies to prevent or reverse DOX-mediated myocardial injury, highlighting the urgent need for novel therapeutic approaches.

Objectives: In this study, the cardioprotective effects of crocin, a natural compound derived from Crocus sativus, were investigated in the context of DOX-mediated cardiotoxicity.

Methods: Cardiac function, mitochondrial morphology, ROS production, and ATP content were evaluated in both in vitro and in vivo models of DOX-mediated cardiotoxicity. RNA sequencing was performed to identify key regulatory pathways affected by crocin. Mitophagy-related mechanisms were investigated through molecular and cellular assays, including immunofluorescence and Western blot analysis of PTEN-induced kinase 1 (PINK1)-associated signaling. PINK1 knockdown and mitophagy inhibition were performed to assess the impact on the cardioprotective effects of crocin.

Results: Crocin treatment preserved cardiac function and mitigated DOX-mediated myocardial injury in both in vitro and in vivo models, as evidenced by restored left ventricular ejection fraction, reduced mitochondrial ROS accumulation, restoration of ATP production, and improved mitochondrial morphology. Transcriptomic analysis revealed that crocin upregulated PINK1 expression, a key initiator of mitophagy. Functional assays further confirmed that crocin restored mitophagy activity suppressed by DOX exposure. The cardioprotective effects of crocin were abolished upon PINK1 knockdown or mitophagy inhibitor, highlighting the essential role of PINK1-dependent mitophagy in mediating crocin's effects.

Conclusions: Crocin protects against doxorubicin-induced cardiotoxicity by activating PINK1-mediated mitophagy and maintaining mitochondrial homeostasis. These findings highlight crocin as a potential therapeutic agent for mitigating DOX-mediated cardiotoxicity.

Background: Diabetic cognitive impairment (DCI) is an increasingly recognized complication of type 2 diabetes mellitus (T2DM) with limited effective therapies. Short-chain fatty acids (SCFAs) have been implicated in metabolic regulation and neuronal health, yet comparisons of acetate, propionate, butyrate, and their mixture are limited, and the mechanisms underlying neuroprotection in DCI remain insufficiently clarified.

Methods: Ninety participants (healthy controls, T2DM, and DCI groups) were assessed for serum SCFA levels and cognitive performance using the Montreal Cognitive Assessment (MoCA). In parallel, a DCI mouse model established by a 24-week high-fat diet received 8-week supplementation with acetate, propionate, butyrate, or a mixture of the three. Glucolipid metabolism, spatial learning and memory, hippocampal neuronal damage, neuroinflammation, and mitophagy were evaluated. Based on consistency across the clinical and animal datasets, acetate was selected for mitophagy-focused mechanistic experiments, and pathway dependence was examined by co-administration of the autophagy inhibitor 3-methyladenine (3-MA).

Results: Clinically, serum acetate, propionate, and butyrate were lower in T2DM and DCI than in healthy controls; only acetate showed a further significant reduction in DCI compared with T2DM. All three SCFAs were positively associated with MoCA score and inversely associated with fasting blood glucose, whereas acetate additionally showed inverse associations with lipid parameters. In mice, SCFA supplementation alleviated metabolic dysfunction, spatial learning and memory, neuronal loss, and neuroinflammation, with acetate generally producing more consistent and numerically greater improvements across these endpoints. Mechanistically, acetate enhanced hippocampal mitophagy by restoring LC3-TOMM20 colocalization and activating the PINK1/Parkin pathway. Importantly, 3-MA partially attenuated these benefits, indicating a mitophagy-dependent mechanism.

Conclusions: These integrated clinical and experimental data support a "SCFAs-mitophagy-neuroinflammation" axis linking systemic metabolism to neuronal vulnerability in DCI, and identify acetate as a promising SCFA that may enhance neuronal resilience through mitophagy activation.