Abnormal cardiac lipid metabolism is a major contributor to cardiovascular disease (CVD). The nuclear receptor Rev-erb-α is recognized as a regulator of lipid metabolism; however, its role in cardiomyocyte lipotoxicity remains undefined. This study aims to investigate the functional role of Rev-erb-α in palmitic acid (PA)-induced lipid accumulation and peroxidation in cardiomyocytes. H9c2 cardiomyocytes are treated with the canonical Rev-erb agonists SR9009 and GSK4112 in combination with PA. Intracellular lipid droplet accumulation is quantified using Oil Red O, Nile red, and BODIPY 493/503 staining. Cytoplasmic and mitochondrial reactive oxygen species (ROS) levels are measured using 2',7'-DCFDA, dihydroethidium, and Mito-SOX probes, respectively, while DNA damage is assessed by quantifying the markers 53BP1 and γ-H2AX. Additionally, siRNA-mediated knockdown and adenovirus-mediated overexpression of Rev-erb-α are employed to validate its role in H9c2 and/or neonatal rat ventricular cardiomyocytes. PA treatment downregulates Rev-erb-α protein expression. Surprisingly, both SR9009 and GSK4112 exacerbate lipid droplet production and ROS production while activating the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) antioxidant pathway, independent of Rev-erb-α. However, direct adenovirus-mediated overexpression of Rev-erb-α significantly attenuates lipid droplet formation and mitochondrial ROS, which is reversed by the Nrf2 inhibitor brusatol. Mechanistically, Rev-erb-α functions as a transcriptional activator of Nrf2. Our results demonstrate a direct protective role for Rev-erb-α against lipotoxic stress and crucially reveal that its commonly used agonists have confounding, off-target pro-oxidant effects. These findings have critical implications for developing Rev-erb-α-targeted therapies for CVDs.
Traditional photothermal antibacterial therapy is limited by a narrow therapeutic window. Here, myricetin-functionalized Prussian blue analog nanoparticles (M@HPBA) are developed as a multimodal platform for methicillin-resistant Staphylococcus aureus (MRSA) infection and wound repair. Doping with cobalt, zinc, and copper enhances photothermal conversion and enzyme-mimetic activities. Under near-infrared irradiation, localized heating induces bacterial damage and triggers the controlled release of metal ions and myricetin. Released myricetin scavenges excess reactive oxygen species, alleviating oxidative stress and inflammation to promote healing. In vitro, M@HPBA with irradiation achieves high antibacterial efficiency against MRSA. In a murine wound infection model, this strategy markedly reduces bacterial burden and accelerates tissue regeneration, with a wound closure rate significantly higher than controls. Transcriptomic analysis reveals that M@HPBA regulates inflammatory and antioxidant pathways in MRSA-infected wounds, enhancing susceptibility to photothermal and ROS/metal ion killing. M@HPBA demonstrates broad-spectrum antibacterial activity and favorable biosafety. These findings establish a synergistic strategy integrating photothermal therapy, nanozyme catalysis, ion release, and antioxidant intervention, providing a translatable paradigm for precision antimicrobial therapy and infected wound management.
Hyperglycemia is a poor prognostic factor in critically ill septic patients with diabetes. Acute lung injury (ALI) resulting from hyperglycemia combined with sepsis remains an urgent clinical challenge. However, the mechanisms by which hyperglycemia contributes to sepsis-associated ALI remain unclear. In this study, we investigate the molecular mechanisms through which hyperglycemia accelerates ALI and mortality in sepsis using in vivo and in vitro models. High NPM3 expression not only mediates H3K18la levels but also promotes its binding to the ACSL1 promoter. Elevated ACSL1 expression and abnormal subcellular organelle localization disrupt lipid metabolism in macrophages, ultimately leading to ferroptosis. Our findings indicate that hyperglycemia enhances ferroptosis via the NPM3-H3K18la-ACSL1 axis in macrophages during sepsis-associated ALI. Targeted inhibition of this axis effectively suppresses hyperglycemia-induced ferroptosis in macrophages and reduces ALI and mortality in septic mice. Thus, targeting the NPM3-H3K18la-ACSL1 axis represents a promising therapeutic strategy for hyperglycemic/diabetic patients with sepsis-associated ALI.
The orphan nuclear receptor NR2F1 has been shown to associate with a dormant tumor state in multiple tumor models. However, its dynamic regulation, particularly at the level of protein post-translational modification, remains largely unclear. In this study, we identify the deubiquitinase ubiquitin-specific peptidase 11 (USP11) as a potential regulator that controls the protein stability of NR2F1. USP11 directly interacts with NR2F1, and its overexpression increases NR2F1 protein level by suppressing NR2F1 protein turnover. Mechanistically, USP11 deubiquitinates NR2F1 at K70 and K369 to protect it from proteasomal degradation. Consistent with these findings, USP11 and NR2F1 expression levels are positively correlated across multiple tumor types. Notably, elevated expression of either USP11 or NR2F1 predicts a better prognosis in kidney renal clear cell carcinoma, indicating their potential clinical significance. Together, these findings reveal a post-translational regulatory mechanism of NR2F1 and suggest that targeting USP11 may provide a potential strategy for modulating tumor dormancy.
The establishment of the epidermal barrier is essential for terrestrial vertebrate survival. Retroviral-like aspartic protease 1 (ASPRV1), also known as skin aspartic protease (SASPase), plays a central role in this process by facilitating the initial cleavage of profilaggrin into filaggrin monomers, which is vital for skin hydration and barrier integrity. Mutations disrupting this activity are linked to hereditary skin disorders. Evolutionarily, ASPRV1 originated from the domestication of an ancient retroviral sequence and comprises a Gag-like domain and a C-terminal protease domain. While it shares structural similarity with HIV-1 protease (HIV-1 PR), the molecular basis for its unique enzymatic properties and substrate specificity remains unclear. Here, we present the biochemical characterization and crystal structures of mature human ASPRV1 (ASPRV1-14) in multiple states, including wild-type, catalytically inactive mutants bound to self-cleavage and filaggrin peptides, and a complex with the HIV-1 PR inhibitor indinavir. Our results demonstrate that ASPRV1-14 exhibits an ionic strength-dependent monomer-dimer equilibrium, shifting from a low-activity monomer at low ionic strength to a high-activity dimer at high ionic strength. Structural analysis reveals that ASPRV1-14 possesses distinctly hydrophobic S2/S2' pockets, dictating a strict requirement for hydrophobic residues at the P2/P2' positions of substrates and explaining its resistance to most HIV-1 PR inhibitors, except indinavir. Furthermore, analysis of disease-associated mutations indicates two main pathogenic mechanisms: disrupting the S2/S2' pocket ( e. g., V243A) or interfering with the self-cleavage maturation process ( e. g., I186T, K199E, R311C/P, and P314T). Collectively, these findings provide a comprehensive molecular framework for understanding the roles of ASPRV1 in epidermal homeostasis and the pathogenesis of skin diseases, offering insights for future therapeutic development.
Pannexin 1 (PANX1), a member of the gap junction protein family, is ubiquitously expressed across various tissues and plays a key role in ATP release and signal transduction. In this study, we investigate Panx1 expression in cardiac fibroblasts under pathological conditions, specifically focusing on heart failure. Transcriptomic analysis reveals that Panx1 expression is upregulated in mouse hearts after transverse aortic constriction (TAC) surgery. Single-cell sequencing data from TAC mice indicate that Panx1 is predominantly expressed in fibroblasts, and its expression is significantly elevated in TAC mice. The upregulation of the PANX1 protein in fibroblasts following TAC is further corroborated by immunofluorescence staining and western blot analysis. Similarly, single-cell sequencing data from human heart failure patients are consistent with those from TAC mice, showing high PANX1 expression in fibroblasts. Pathway enrichment analysis of fibroblasts with differential Panx1 expression reveals that the JAK/STAT signaling pathway is commonly enriched in both species. In vitro knockdown and overexpression of the Panx1 gene are used to demonstrate its effect on the fibroblast phenotype. In vivo injection of a PANX1 blocker provides evidence for the role of Panx1 in alleviating cardiac fibrosis. The PANX1 channel is expressed in cardiac fibroblasts and is upregulated after TAC. Bioinformatics analysis suggests that this process is associated with the JAK/STAT signaling pathway. The Panx1 gene regulates phenotypic changes in fibroblasts and activates the downstream JAK/STAT signaling pathway via the ATP-purinergic receptor.
Although homeotherms maintain a stable core body temperature through the coordinated regulation of multiple physiological systems, various factors can still lead to abnormal body temperature. While the immune-enhancing effects of fever are well understood, research on how low body temperature regulates immunity remains limited. Notably, cold therapy and hypothermia have been used to manage various diseases, including neurological and metabolic disorders. This review provides a comprehensive overview of the causes of hypothermia, its modulatory effects on immunity and underlying mechanisms, and its therapeutic applications in clinical diseases.
Cadmium (Cd), an environmental neurotoxic pollutant, is believed to have adverse effects on cognitive function in humans. Recent studies have linked the induction of ferroptosis to Cd-induced cytotoxicity. Melatonin (Mel) has been shown to exert anti-ferroptotic and neuroprotective effects in nervous system diseases. This study aims to investigate whether ferroptosis inhibition by Mel can ameliorate Cd-induced neuronal/synaptic injury in the hippocampus and cognitive dysfunction and to explore the underlying mechanisms involved. Daily intraperitoneal injections of Mel (20 mg/kg per day) for 8 weeks significantly mitigate Cd-evoked cognitive deficits. Furthermore, the reduction in the number of Nissl-positive neurons in the hippocampus and in the synaptic density following Cd exposure is prevented by Mel administration. Mechanistically, Mel supplementation significantly inhibits ferroptosis in Cd-treated mouse hippocampal HT-22 neurons and in the mouse hippocampus. Mel suppresses mtROS-ferritinophagy and thereby decreases Cd-induced cellular iron overload by activating Nrf2 in HT-22 neurons. Moreover, Nrf2 activation by Mel markedly restores GPX4 deficiency and prevented lipid peroxidation under Cd stress in vitro. However, the anti-mtROS-ferritinophagic and anti-ferroptotic effects of Mel are abolished by Nrf2 knockdown in vitro. Overall, exogenous Mel treatment relieves Cd-induced neuronal ferroptotic death in the hippocampus and cognitive impairment through the inhibition of mtROS-ferritinophagy and the increase in GPX4 expression via Nrf2 activation, suggesting that Mel may be a potential therapeutic agent for the treatment of neurotoxicity and neurobehavioral disorders associated with Cd exposure.
Chemoresistance remains a critical barrier to the efficacy of oxaliplatin in colon cancer treatment. While the deubiquitinating enzyme USP46 is implicated in multiple tumor progression pathways, its specific role in oxaliplatin resistance remains undetermined. Our analysis reveals that USP46 is significantly overexpressed in colon cancer tissues, with its elevated expression correlating with poor clinical outcomes in colon cancer patients. Silencing USP46 suppresses both the proliferation and metastatic potential of colon cancer cells while simultaneously enhancing cellular sensitivity to the DNA-damaging agent oxaliplatin. Mechanistically, overexpression of USP46 leads to upregulation of nuclear RAD51 expression and facilitates the assembly of RAD51 foci, thereby increasing homologous recombination repair (HRR) capacity and contributing to oxaliplatin resistance in colon cancer cells. MCM7 is identified as a bona fide substrate of USP46 by LC-MS/MS profiling. Subsequent experiments confirm that USP46 specifically removes K48-linked polyubiquitin chains from MCM7, thereby stabilizing its protein expression. Rescue assays validate that USP46 modulates RAD51 expression and HRR function in an MCM7-dependent manner. Collectively, our study uncovers a novel USP46-MCM7-RAD51 signaling cascade that confers oxaliplatin resistance in colon cancer via augmentation of HRR-dependent DNA repair, thereby establishing this axis as a promising therapeutic target for overcoming oxaliplatin resistance.
Taraxasterol (TAR) exerts therapeutic effects on various liver diseases via its inherent hepatoprotective and anti-inflammatory properties. However, the mechanism by which TAR treats hepatic fibrosis remains unclear. This study aims to identify the potential targets and specific molecular mechanisms underlying the therapeutic effects of TAR on hepatic fibrosis. DDC- and CCl 4-induced mouse models of hepatic fibrosis are established. The human hepatic stellate cell (HSC) line LX-2 and primary mouse HSCs are used for in vitro experiments. Transcriptomics, network pharmacology, single-cell transcriptomics, and molecular docking are employed to identify potential therapeutic targets of TAR for hepatic fibrosis. Functional validation is performed via HSD11B1 overexpression and knockdown experiments, and the regulatory role of the ERK MAPK pathway is verified using the specific inhibitor U0126. Histological staining results show that TAR significantly alleviates DDC- and CCl 4-induced hepatic fibrosis in mice and reduces associated liver injury. In vitro assays reveal that TAR effectively reverses TGF-β-induced activation of LX-2 cells and primary mouse HSCs. Multi-omics and docking analyses identify HSD11B1 as a direct target of TAR, whose downregulation in activated HSCs is restored by TAR treatment. Functional experiments demonstrate that overexpression of HSD11B1 attenuates TGF-β-induced HSC activation, while HSD11B1 knockdown abolishes the therapeutic effects of TAR. Subsequent transcriptomic analysis confirms that HSD11B1 suppresses the ERK MAPK pathway, and knockdown of HSD11B1 compromises the therapeutic efficacy of the ERK MAPK inhibitor U0126. In summary, TAR alleviates liver fibrosis by inhibiting HSC activation through the HSD11B1-ERK MAPK axis.
