Free Radical Biology and Medicine最新文献

Porcine epidemic diarrhea virus (PEDV) causes severe diarrhea and high mortality in neonatal piglets, largely due to oxidative stress-induced epithelial injury. However, the molecular mechanisms by which viral and host factors regulate redox homeostasis during PEDV infection remain unclear. In this in vitro study, we used IPEC-J2, LLC-PK1, and HEK293T cells to demonstrate that PEDV disrupted intracellular redox balance by suppressing glutathione biosynthesis through inhibition of the glutathione synthetase (GSS) and glutamate-cysteine ligase (GCL). Increasing GSH levels suppressed PEDV replication, whereas blocking GSH synthesis enhanced viral replication. We further found that PEDV impaired the Nuclear factor erythroid 2-related factor 2 (NRF2)/Heme Oxygenase-1 (HO-1) antioxidant signaling pathway. NRF2 overexpression or pharmacological activation inhibited PEDV replication, whereas NRF2 knockdown promoted viral replication. Screening of PEDV-encoded proteins identified Non-structural protein 1 and 2 (NSP1) and Non-structural protein 2 (NSP2) as viral factors that destabilized NRF2 through proteasomal degradation. Mechanistically, NSP1 and NSP2 interacted with the double glycine repeat (DGR) domain of Kelch-like ECH-associated protein 1 (KEAP1), strengthening KEAP1-NRF2 binding. NSP1 reduced K63-linked ubiquitination of NRF2, while NSP2 enhanced its K48-linked ubiquitination, thereby cooperatively accelerating NRF2 degradation. In summary, this study identified a previously unrecognized mechanism by which PEDV induces oxidative stress through coordinated viral modulation of the GSS and GCL and NRF2/HO-1 pathways. These findings highlight key redox-regulatory nodes that may serve as promising targets for antiviral drug and vaccine development.

A cytokine storm caused by respiratory syncytial virus (RSV) significantly influences the progression of pneumonia and bronchiolitis. It is essential to comprehend the underlying mechanism of the RSV-triggered cytokine storm to effectively manage RSV. Hypoxia-inducible factor-1 Alpha (HIF-1α) plays a pivotal role in innate immunity. It is known that RSV enhances HIF-1α expression, but the molecular mechanism of RSV-induced HIF-1α expression and its role in the production of innate inflammatory cytokines during RSV infection are not fully understood. Our research demonstrates that RSV infection increases HIF-1α expression both in vitro and in vivo. Further investigation into the mechanism of RSV-induced HIF-1α expression indicates that PKCδ regulates RSV-induced HIF-1α translation through the PI3K/Akt/mTOR signaling pathway. Additionally, HIF-1α expression, mediated by PKCδ/PI3K/Akt/mTOR signaling, stimulates the production of innate inflammatory cytokines by activating the NLRP3-inflammasome during RSV infection. Inhibition of HIF-1α or PKCδ markedly suppresses RSV-induced inflammation in vitro and in vivo. In summary, these findings elucidate the molecular mechanism of RSV-induced HIF-1α expression and identify HIF-1α as a novel target for anti-RSV drug development.

Introduction: Aging is characterized by the progressive decline of physiological integrity, and its driving factors include mitochondrial dysfunction, epigenetic changes and metabolic imbalance. Although some studies have shown that glycine (Gly) has anti-aging protection, its mechanism has not been clarified.

Objectives: The purpose of this study is to explore the mechanism of Gly in anti-aging and improving aging-related phenotype, and to clarify the molecular pathway of Gly promoting healthy aging.

Methods: Fruit fly and aged rat models were used to evaluate the effect of Gly supplementation. Life span, stress resistance and functional phenotype were evaluated in fruit flies, and biochemical, histological and physiological indexes related to aging were detected in aged rats. Transcriptomic and metabolomic profiling, along with gene knockdown approaches, were used to identify key pathways and targets involved in Gly-mediated effects.

Results: In fruit flies, Gly extended lifespan and ameliorating aging-related phenotypes, with Gly dose-dependently upregulated the expression of Nmdmc, whose knockdown abolished these beneficial effects, indicating the essential role of Nmdmc in Gly-mediated activation of one-carbon metabolism (OCM). Metabolomic identified glyceric acid as a key metabolite linked to improved mitochondrial energy metabolism. In aged rats, Gly also upregulated Mthfd2 (the mammalian ortholog of Nmdmc) and reduced neuronal damage in the hippocampus, restored hepatic cell architecture, and increased muscle fiber density, accompanied by enhanced mitochondrial biogenesis and methylation markers.

Conclusion: Gly supplementation alleviated aging-related dysfunction by up-regulating Nmdmc and remodeling mitochondrial OCM, which could help to improve DNA repair, mitochondrial function and oxidative stress resistance.

p-Phenylenediamine (p-PD), an emerging organic contaminant, poses increasing concern for aquatic ecosystems, yet its toxicological impact on fish remains inadequately addressed. This study investigated the biochemical, molecular, and histopathological alterations in the liver and eye of Oreochromis mossambicus exposed to a sublethal concentration (73.3 μg L^-1) and an environmentally relevant concentration (235.3 ng L^-1) of p-PD for 1, 7, 14, 30, 45, and 60 days. Exposure to p-PD significantly induced oxidative and nitrative stress in nuclear, mitochondrial, and cytosolic fractions of both tissues, as evidenced by alterations in antioxidant responses, including superoxide dismutase, glutathione reductase, glutathione peroxidase, glutathione redox ratio, total antioxidant capacity, and oxidative stress indicators such as lipid peroxidation and hydrogen peroxide formation. The transcriptional expression of sod and gpx genes further confirmed disruptions in oxidative defence mechanisms. Enhanced nitrative stress was evidenced by elevated levels of nitrate, nitrite, nitric oxide, and 3-nitrotyrosine. Besides, tissue dysfunction was indicated by significant changes in aspartate aminotransferase, alanine aminotransferase, alkaline phosphatase, acid phosphatase, lactate dehydrogenase, and α-fucosidase activities. Histopathological analysis revealed pronounced structural damage, including necrosis, inflammation, and marked architectural disruption in hepatic and ocular tissues. The integrated biochemical, molecular, and morphological findings demonstrate that p-PD induces considerable hepatic and ocular toxicity in O. mossambicus. These results underscore the ecological risk posed by p-PD and highlight the need for further investigation to support long-term environmental monitoring and regulatory measures.

The integrity of blood-brain barrier (BBB) plays a pivotal role in the pathogenesis of Alzheimer's disease (AD) by regulating Aβ clearance and neurotoxic compound exclusion. Hyperlipidemia exacerbates AD by impairing the BBB function. Inclisiran, a PCSK9-targeting siRNA, reduces cholesterol levels; however, its neuroprotective effects remain unclear. Here, we report the novel discovery that Inclisiran attenuates AD-like changes through the PCSK9-ferroptosis axis in brain microvascular endothelial cells (BMECs). First, integrated bioinformatics analysis and experimental validation of cortical tissues from patients with AD and healthy controls revealed a coordinated upregulation of PCSK9 and β-amyloid (Aβ), accompanied by increased iron deposition and significant activation of the ferroptosis pathway. Interestingly, these changes are located in the BMECs of the blood-brain barrier rather than in the brain parenchyma. Second, in hyperlipidemic ApoE^-/- mouse models, integrated application of cerebral microvessel isolation, molecular biology techniques, immunofluorescence co-localization analysis, and behavioral tests demonstrated that Inclisiran significantly reduced AD-like changes by attenuating BBB dysfunction based on the suppression of PCSK9-mediated ferroptosis in BMECs. Third, in vitro studies employing the HCMEC/D3 BBB model with integrated assessments of lipid peroxidation, mitochondrial function, and transwell-based barrier integrity demonstrated that Inclisiran significantly reduced ferroptosis and restored BBB integrity via PCSK9 suppression. Our findings not only establish a novel PCSK9-ferroptosis-BBB regulatory axis in AD pathogenesis but also posit the clinically approved lipid-lowering drug, Inclisiran, as a promising therapeutic candidate for AD, providing new targets and mechanisms for the prevention and treatment of AD.

Non-small cell lung cancer (NSCLC) remains a lethal malignancy due to therapy resistance and recurrence. Ferroptosis, a regulated form of cell death, is a promising strategy to overcome cancer drug resistance, yet its mechanisms remain incompletely defined. Here, we report that Immediate Early Response 3 (IER3) is significantly upregulated in NSCLC tumors and linked to advanced stage and poor prognosis. Using IER3-overexpressing and knockout models in A549 and H1299 cells, we found that IER3 promotes NSCLC cell proliferation, migration, and invasion by suppressing ferroptosis. Conversely, IER3 knockout induced ferroptosis and reduced malignancy-effects reversed by the ferroptosis inhibitor Fer-1. Mechanistically, IER3 sustained AKT phosphorylation to inactivate GSK3β, both blocking GSK3β-dependent proteasomal degradation of NRF2 and enhancing its nuclear translocation, which collectively led to the transactivation of downstream ferroptosis-suppressive gene programs. This program maintained glutathione homeostasis, sequestered labile iron, scavenged ROS, and ultimately inhibited lipid peroxidation to counter ferroptosis. Rescue assays confirmed NRF2 overexpression or AKT/GSK3β activation reversed IER3 knockout-induced ferroptosis and viability loss. Additionally, low-IER3 NSCLC tumors were more sensitive to clinical/preclinical agents targeting survival/stress pathways. Collectively, our findings establish IER3 as an NSCLC oncogenic driver-suppressing ferroptosis via AKT/GSK3β/NRF2 to sustain malignancy-highlighting its potential as a prognostic biomarker and therapeutic target for improved NSCLC outcomes.

Renal ischemia-reperfusion injury (RIRI) is a common cause of acute kidney injury in clinical practice, frequently occurring in renal transplantation, partial nephrectomy, and cardiac surgery. Similar to phosphorylation and ubiquitination, glycation is a form of post-translational modification that is widely present in mammals. However, glycation/deglycation has not yet been investigated in the context of RIRI. To explore its regulatory role in acute-phase RIRI, we established both in vivo and in vitro renal ischemia-reperfusion models and examined the protective mechanism of the deglycating enzyme fructosamine-3-kinase (FN3K). Our results demonstrated that FN3K expression was markedly down-regulated following RIRI. FN3K over-expression alleviated renal injury in mice and cells, primarily by reducing oxidative stress and apoptosis, whereas FN3K knockdown exerted the opposite effects. Mechanistically, the protective role of FN3K was dependent on Nrf2. Specifically, FN3K promoted the nuclear translocation and antioxidant activity of Nrf2 by mediating its deglycation. In conclusion, this study is the first to reveal that FN3K confers protection against RIRI by regulating Nrf2 deglycation, thereby broadening our understanding of oxidative stress mechanisms underlying ischemia-reperfusion-induced acute kidney injury. Furthermore, these findings provide a novel theoretical basis for targeting the FN3K-Nrf2 signaling axis, and highlight a potential therapeutic target for precision intervention in acute kidney injury and the prevention of post-transplant complications.