Free Radical Biology and Medicine最新文献

N⁶-methyladenosine (m⁶A) modification plays a critical role in tumor progression and drug resistance. Here, we demonstrate that METTL3-mediated m⁶A modification contributes to anlotinib resistance in osteosarcoma by regulating ferroptosis through the circFAM120B/miR-330-3p/PRKDC axis. We show that anlotinib triggers ferroptosis in osteosarcoma cells by suppressing the VEGFR2/STAT3/GPX4 signaling cascade. DNA-PKcs (encoded by PRKDC) interacts with IGF1R and activates the IGF1R/STAT3/GPX4 pathway, thereby inhibiting ferroptosis. Mechanistically, circFAM120B functions as a molecular sponge for miR-330-3p, leading to PRKDC upregulation. METTL3 enhances circFAM120B stability via YTHDF1-dependent recognition and facilitates its expression, while also promoting YTHDF2-mediated degradation of pri-miR-330, resulting in reduced mature miR-330-3p. In vivo studies confirm that METTL3 overexpression increases anlotinib resistance, which is counteracted by circFAM120B knockdown or miR-330-3p overexpression. Notably, while ferroptosis represents a key mechanism, STAT3 may also contribute to anlotinib resistance through additional pathways including apoptosis, autophagy, and immune evasion, reflecting the multifunctional role of this central signaling hub. Our results delineate a novel mechanism wherein METTL3 governs ferroptosis and anlotinib resistance in osteosarcoma through dual m⁶A methylation of circFAM120B and pri-miR-330, offering potential targets for overcoming therapeutic resistance.

Hydroxyl radicals are among the most reactive and destructive reactive oxygen species, capable of inducing severe oxidative damage to critical biomolecules-including proteins, DNA, and lipids-thereby contributing to cellular dysfunction, senescence, apoptosis, and the pathogenesis of numerous diseases. In contrast, hydrogen sulfide (H₂S) has emerged as a key endogenous signaling molecule with well-documented antioxidant, anti-inflammatory, and tissue-repair properties, prompting growing interest in its therapeutic applications. This study developed a novel hydroxyl radical-responsive hydrogen sulfide donor (HSD-FA-OH), which can release carbonyl sulfide (COS) in environments with elevated hydroxyl radical levels. The COS is rapidly converted by intracellular carbonic anhydrase to release hydrogen sulfide, thereby achieving targeted physiological modulation. Accumulating evidence indicates that H₂S exerts anti-inflammatory effects through the regulation of macrophage polarization. To enhance specificity and minimize off-target toxicity, we incorporated a folic acid moiety into the donor system, facilitating selective recognition and uptake by macrophages via folate receptor-mediated endocytosis. In a diabetic wound healing model, treatment with this donor significantly promoted M2 macrophage polarization, suppressed M1 polarization, enhanced collagen deposition and neovascularization, and accelerated wound closure. These findings demonstrate the therapeutic potential of redox-responsive, macrophage-targeted H₂S donors and provide a rational strategy for the precise modulation of inflammatory microenvironments.

Oxygen therapy is required for the survival of premature infants with respiratory distress, yet hyperoxia exposure is a major contributor to alveolar developmental arrest in bronchopulmonary dysplasia (BPD). Despite the recognized role of fibroblasts in lung development, their functional contributions to the alveolar niche under hyperoxia remain poorly defined. Here, we profiled the involvement of fibroblasts using a BPD model induced by moderate hyperoxia (60% oxygen). Single-cell RNA sequencing (scRNA-seq) revealed that fibroblasts transitioned toward a disease-associated phenotype and exhibited enhanced communication with type II alveolar epithelial cells (AEC IIs) under moderate hyperoxia. Furthermore, activated fibroblasts increased the susceptibility of AEC IIs to hyperoxia via extracellular vesicles (EVs). These EVs were enriched with mitochondrial components, particularly the outer mitochondrial membrane (OMM) protein VDAC1. OMM-enriched EVs inhibited BNIP3-dependent mitophagy initiation in AEC IIs via VDAC1-GCN2 complex formation, leading to autophagic flux blockade and mitochondrial dysfunction. Inhibition of fibroblast-derived EV release using GW4869 or administration of human umbilical cord mesenchymal stem cell (hUC-MSC)-derived EVs attenuated hyperoxia-induced AEC II dysfunction and alveolar structural impairment. Taken together, our findings identify a fibroblast-epithelial communication mechanism that impairs mitochondrial homeostasis and leads to alveolar developmental arrest, highlighting a promising therapeutic target for BPD.

Obstructive Sleep Apnea Hypopnea Syndrome (OSAHS) significantly contributes to cardiovascular diseases through severe endothelial dysfunction, a pathology driven primarily by chronic intermittent hypoxia (CIH)-induced oxidative stress and inflammation. Current interventions inadequately address this vascular component. Human umbilical mesenchymal stem cell-derived extracellular vesicles (HUMSC-EVs) have regenerative potential, but improved targeting is needed to maximize therapeutic efficacy. This study sought to engineer and evaluate Intercellular Adhesion Molecule 1 (ICAM-1) targeted EVs loaded with the Transient Receptor Potential Channel C5 (TRPC5) inhibitor HC-070 (ICAM-1⁺H-EVs) for their ability to ameliorate oxidative damage in OSAHS. We employed a CIH mouse model and IH-treated HUVECs, and characterized ICAM-1⁺H-EVs using Western blotting and ExoView. ICAM-1⁺H-EVs significantly enhanced HUVEC uptake and, in both in vivo and in vitro settings, alleviated oxidative stress by lowering Reactive Oxygen Species (ROS) and Malondialdehyde (MDA) levels and restoring the activities of antioxidant enzymes Superoxide Dismutase (SOD) and Glutathione Peroxidase (GSH-PX). Furthermore, ICAM-1⁺H-EVs substantially suppressed inflammation by lowering TNF-α and IL-6 levels and mitigated mitochondrial ROS and morphological damage. This novel strategy targets TRPC5-mediated calcium influx, providing a potent therapeutic approach to interrupt the oxidative stress and inflammatory cycle driving OSAHS-associated vascular dysfunction.

The oxysterol 27-hydroxycholesterol (27OHC), which is widely distributed in various tissues and circulation, plays a notable role in pathological processes, such as including breast cancer, atherosclerosis, and neurodegenerative diseases. Although these processes are closely linked to muscle pathophysiology, the effects of 27OHC on metabolic changes associated with muscular atrophy and sarcopenia remain poorly understood. In this study, we demonstrated that 27OHC decreased skeletal muscle viability by activating pro-apoptotic signaling pathways. RNA sequencing revealed that 767 and 989 genes were upregulated and downregulated, respectively, in 27OHC-treated myoblasts. Upregulated genes were associated with hypoxia-inducible factor 1-alpha response, whereas downregulated genes were commonly involved in the phosphoinositide 3-kinase pathway and muscle differentiation process. Myoblast cell death induced by 27OHC was mediated by generation of reactive oxygen species followed by mitochondrial morphological impairments and disruption of mitochondrial membrane potential (ΔΨm). Moreover, 27OHC reduced mitochondrial gene expression via glycogen synthase kinase-3 beta activation, ultimately leading to increased mitochondrial ROS. Concurrently, hypoxia-inducible factor 1-alpha induction upon 27OHC exposure activated cellular defense mechanisms to mitigate oxidative damage. In addition, a significant reduction was observed in the expression of genes involved in myotube differentiation and fusion index following 27OHC treatment, and hypoxia-inducible factor 1-alpha knockdown further aggravated the impairment of tube formation. Furthermore, mice treated with 27OHC exhibited reduced exercise endurance, decreased muscle cross-sectional area, and impaired muscle recovery following barium chloride-induced injury. As plasma levels of 27OHC are increased in elderly individuals, our findings suggest that pharmacological inhibition of 27OHC generation could be a therapeutic strategy to treat age-related muscle atrophy.

Nanozymes with superoxide dismutase (SOD) activity represent a class of artificial enzymes that mimic the catalytic function of natural SOD. This review systematically summarizes the recent advancements in SOD-like nanozymes, focusing on their catalytic mechanisms, material classifications, and biomedical applications. It begins by elucidating the enzymatic mechanisms of native SOD isoforms dependent on their metal cofactors (Cu/Zn, Mn, Fe, Ni). The article then classifies and discusses various synthetic nanozymes, including those based on metals, metal oxides, metal-organic frameworks (MOFs), and carbon nanomaterials, which exhibit potent ROS scavenging capabilities. Key factors influencing their catalytic performance-such as size, morphology, atomic doping, and surface chemistry-are also critically examined. Furthermore, the review highlights their therapeutic potential in mitigating oxidative stress-related diseases, such as inflammation, neurodegenerative disorders, and cancer, and explores their roles in cytoprotection, biosensing, and diagnostics. Finally, current challenges and future prospects toward the clinical translation of SOD nanozymes are outlined.

Different muscles exhibit varied susceptibility to degeneration in Amyotrophic Lateral Sclerosis (ALS), a fatal neuromuscular disorder. Extraocular muscles (EOMs) are particularly resistant to ALS progression, and exploring the underlying molecular nature may offer significant therapeutic value. Reactive aldehyde 4-hydroxynonenal (HNE) is implicated in ALS pathogenesis, and Aldh3a1 is an inactivation-resistant intracellular aldehyde dehydrogenase that detoxifies 4-HNE to protect eyes against UV-induced oxidative stress. We detected prominently higher levels of Aldh3a1 in mouse EOMs compared to other muscles under normal physiological conditions. In an ALS mouse model (hSOD1^G93A) reaching end-stage, Aldh3a1 expression was maintained high in EOMs, substantially elevated in soleus and diaphragm, but only moderately increased in extensor digitorum longus (EDL) muscle, which endured the most severe pathological remodeling, as demonstrated by unparalleled upregulation of a denervation marker Ankrd1. Importantly, sciatic nerve transection in wildtype mice further confirmed induced Aldh3a1 and Ankrd1 expression in an inverse manner across muscle types in response to denervation. Mechanistically, whole-muscle RNA-Seq and pharmacological tests indicate that higher basal levels of lipid oxidation and 4-HNE in soleus and diaphragm muscles may render them more susceptible to the induction of certain Nrf2-dependent antioxidant enzymes, including Aldh3a1, under pathological stress relative to the EDL muscle. Additionally, the identification of the myoblast fusion marker Mymk as an EOM signature gene suggests that the spontaneous activation of satellite cells contributes to high levels of Aldh3a1 in EOMs. Functionally, adeno-associated virus-mediated overexpression of Aldh3a1 protected myotubes from 4-HNE-induced DNA fragmentation and plasma membrane leakage. It also restored MG53-mediated membrane repair, highlighting its potential for clinical applications.

Metabolic dysfunction-associated steatohepatitis (MASH) is characterized by hepatocyte ballooning, inflammation, and varying degrees of fibrosis. Protocatechuic acid (PCA), a naturally occurring phenolic compound found in many fruits and vegetables, exhibits various pharmacological properties. However, the precise mechanisms and molecular targets for MASH treatment remain unclear. In this study, we demonstrate that PCA ameliorates hepatic steatosis, fibrosis, and inflammation in MCD-fed mice and reduces lipid accumulation in hepatocytes via the IRE1-XBP1s signaling pathway. By using activity-based protein profiling (ABPP), we revealed that PCA binds protein disulfide isomerase A6 (PDIA6). Co-immunoprecipitation mass spectrometry (Co-IP-MS) analysis demonstrates that PCA enhances the interaction between PDIA6 and IRE1. This interaction suppresses the IRE1-XBP1s signaling pathway, reduces endoplasmic reticulum stress, and contributes to an anti-lipid deposition effect. PDIA6 knockdown inhibits lipid accumulation and eliminates the therapeutic impact of PCA. Collectively, these findings identify PDIA6 as a novel pharmacological target for PCA in the treatment of MCD-induced MASH, while advancing our understanding of disease pathogenesis.

Mitochondrial stress (MS) is a hallmark of a number of aging-associated neurodegenerative diseases, including Parkinson's disease (PD). Chronic MS in PD disrupts neuronal proteostasis, causing dopaminergic neurodegeneration through inactivation of an E3 ubiquitin ligase, parkin, although the mechanism of its inactivation is not understood. Here, we elucidate a mechanistic framework linking progressive changes in mitochondrial mass with MS-induced alterations in parkin activity. We showed that acute and chronic MS differentially modulate parkin activity and regulate mitochondrial biogenesis by transcriptional control of peroxisome proliferator-activated receptor γ coactivator 1α (PGC1α), through parkin substrate PARIS (parkin-interacting substrate). Acute exposure to the PD neurotoxin, 1-methyl-4-phenylpyridinium (MPP⁺), activates the parkin-PARIS-PGC1α pathway, transiently facilitating mitochondrial biogenesis. However, sustained and repetitive MS leads to parkin mis localisation, inactivation, and aggregation, resulting in PARIS accumulation, repression of PGC1α activity, and loss of mitochondrial mass. Nuclear Factor Erythroid 2-related Factor 2 (NFE2L2 or NRF2) activation by methylene blue (MB) transcriptionally upregulates parkin expression by enhancing its binding to NRF2/antioxidant responsive element (ARE) within the PARK2 promoter. MB treatment in cells exposed to chronic MPP ⁺ reduces PARIS levels, restores PGC1α activity, and rejuvenates mitochondria. These findings underscore the impact of chronic mitochondrial damage on parkin dysfunction in PD and suggest a promising role for MB in protecting against mitochondrial and proteostatic failure in PD by targeting the NRF2-parkin axis.