Acta biochimica et biophysica Sinica最新文献

Ischemic stroke, a severe neurological disorder with a multifactorial pathogenesis, presents significant therapeutic challenges. Calycosin, a natural flavonoid, has diverse biological activities, including antioxidant, anti-inflammatory, and antitumor effects. In this study we investigate the protective effects of calycosin against blood-brain barrier (BBB) damage following cerebral ischemia-reperfusion injury (CIRI) and explore the underlying mechanisms. We employ middle cerebral artery occlusion (MCAO) in rats and oxygen-glucose deprivation (OGD) in bEnd.3 brain microvascular endothelial cells to assess neurological function, BBB integrity, the expression of pyroptosis-related proteins, inflammatory mediator release, endothelial barrier permeability, and cell viability. The results reveal that calycosin significantly ameliorates CIRI-induced BBB damage, as evidenced by improved neurological scores, reduced brain water content, and decreased infarct volume. Calycosin suppresses NLRP3-mediated pyroptosis by downregulating HMGB1, NLRP3, caspase 1, GSDMD, N-GSDMD, and IL-18 expression while reducing the secretion of HMGB1, IL-1β, and IL-18. Additionally, calycosin enhances BBB integrity by decreasing MMP9 and AQP-4 expression and upregulating the expression of tight junction proteins (ZO-1, occludin, and claudin-5). In OGD-treated bEnd.3 cells, calycosin inhibits NLRP3-mediated pyroptosis, reduces inflammatory mediator release, and improves cell viability and barrier function. Notably, molecular docking and molecular dynamics simulations demonstrate that calycosin stably binds to NLRP3 with high affinity, supporting its potential as an NLRP3 inhibitor. These findings indicate that calycosin protects against CIRI-induced BBB damage by inhibiting NLRP3-mediated pyroptosis and modulating tight junction protein expression, indicating that calycosin is a potential therapeutic option for ischemic stroke.

Smurf1 is a member of the Nedd4 family of E3 ubiquitin ligases. Numerous lines of evidence indicate that the membrane localization of Smurf1 is essential for its activity. However, the underlying mechanisms that regulate the membrane localization of Smurf1 remain unclear. Type I phosphatidylinositol phosphate kinase (PIPKI) is a phosphatidylinositol kinase that generates phosphatidylinositol 4,5-bisphosphate (PIP2), which is located in the plasma membrane and regulates cellular processes, including ion channel activity and cell migration. In this study, we show that PIP2 and PIPKI regulate the membrane translocation of Smurf1. Importantly, the recruitment of Smurf1 to the cell membrane through the association of its C2 domain with PIPKI-produced PIP2 is essential for Smurf1-mediated E3 ligase activity and cell migration. Therefore, we identify a PIPKI-PIP2-Smurf1 signaling axis that regulates cell migration.

Long non-coding RNAs (lncRNAs) are an essential class of regulatory molecules that participate in diverse biological processes. However, whether sperm-derived lncRNAs from infertile men contribute to impaired embryo development during in vitro fertilization (IVF) remains unclear. In this study, we investigate the lncRNA expression profiles in sperm from asthenozoospermic patients with poor embryo development and explore their potential roles in early embryo development. Microarray analyses identify 993 differentially expressed lncRNAs in sperm samples from these patients, including 626 downregulated and 367 upregulated probes. Among them, an antisense transcript, lnc-CLCN7, is validated as the most significantly dysregulated lncRNA in an expanded cohort. In situ hybridization demonstrates that lnc-CLCN7 is localized in spermatogenic cells of primate testes and within the nuclei of HTR-8 cells. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses reveal that lnc-CLCN7 is associated with the regulation of ion transport, ion homeostasis and related signaling pathways. Further experiments demonstrate that Lnc-CLCN7 directly binds to the histone modification H3K9me2/3 in HTR-8 cells and that its expression in sperm is modulated by oxidative stress induced by H ₂O ₂ treatment. Additionally, dysregulation of the glycolysis/gluconeogenesis and pyrimidine metabolism pathways in sperm is found to contribute to poor embryo development. Collectively, our findings identify Lnc-CLCN7 as an H3K9me2/3-binding, oxidative stress-responsive lncRNA that may serve as a potential biomarker for predicting poor embryo development in IVF and provide new insights into the molecular mechanisms linking sperm RNA regulation to embryo quality.

Asthma is a prevalent chronic respiratory disease in children. Recently, adjusting the Th1/Th2 imbalance has become a significant focus in asthma immunotherapy. The present study aims to investigate the roles and mechanisms of circDCBLD2 in maintaining the Th1/Th2 immune balance. CircDCBLD2 is downregulated in CD4 ⁺ T cells from asthmatic patients and in CD4 ⁺ T cells from an OVA-induced asthmatic mouse model. Additionally, circDCBLD2 levels are significantly decreased in the PBMCs of asthmatic mice. The expression of circDCBLD2 is positively correlated with the Th1 cytokines IFN-γ and IL-2 but negatively correlated with the Th2 cytokines IL-4 and IL-13. Flow cytometry and ELISA analyses demonstrate that circDCBLD2 overexpression increases the proportion of Th1 cells (CD4 ⁺IFN-γ ⁺) and the levels of Th1 cytokines while decreasing the proportion of Th2 cells (CD4 ⁺IL-4 ⁺) and the levels of Th2 cytokines. Furthermore, circDCBLD2 overexpression alleviates the asthma phenotype in OVA-induced mice, reduces the infiltration of inflammatory cells in the lungs, and corrects the Th1/Th2 imbalance. Mechanistically, circDCBLD2 is found to target miR-26a-5p. Rescue experiments indicate that circDCBLD2 regulates the Th1/Th2 immune balance by targeting miR-26a-5p. Additionally, PTEN has been identified as a direct target of miR-26a-5p. The overexpression of PTEN partially reverses the effects of miR-26a-5p on the Th1/Th2 immune balance. These findings indicate that circDCBLD2 increases the proportion of Th1 cells and decreases the proportion of Th2 cells via the miR-26a-5p/PTEN axis, providing a promising target for asthma treatment.

Ultraviolet-B (UVB) radiation induces significant skin damage by penetrating into the dermal layer, leading to reactive oxygen species (ROS) generation and triggering cellular necrosis and apoptosis. Conventional sunscreens focus primarily on UVB blocking but are limited in their ability to repair dermal damage due to insufficient permeability. In this study, we discover that chebulinic acid (CA), one of the principal monomers in Terminalia chebula Retz., has superior efficacy in promoting recovery from UVB-induced skin damage compared with other major monomers. Mechanistically, CA's anti-UVB function involves regulating the expression of IL-6 and IFN-β through activation of the MAPK pathway. To overcome the formidable barrier posed by the skin, we identify mulberry exosome-like nanoparticles (MELNs) as an efficient transdermal delivery system and develop CA@MELNs loaded with CA. Furthermore, we demonstrate that the dissociative CA within the CA@MELNs delivery system significantly enhances both transdermal penetration and anti-UVB efficiency in vitro and in vivo. Our findings suggest the substantial potential of CA as an effective ingredient and CA@MELNs as a robust and accessible platform for mitigating UVB damage.

Cerebral ischemia-reperfusion injury (CIRI) significantly exacerbates neuronal damage following ischemic stroke. Emerging evidence implicates PANoptosis, a novel inflammatory form of programmed cell death, in CIRI pathogenesis. However, the role of Z-DNA-binding protein 1 (Zbp1), a key regulator of PANoptosis and innate immune responses, remains poorly understood in this context. Here, we establish a middle cerebral artery occlusion/reperfusion (MCAO/R) mouse model and an oxygen-glucose deprivation/re-oxygenation (OGD/R) model in which HT-22 cells are used to simulate CIRI and investigate the effects of Zpb1. Western blot analysis is performed to assess Zbp1 and PANoptosis-related protein expressions. Cell viability and death are evaluated using Hoechst 33342 staining and Calcein AM/PI assays, and the cerebral infarct volume is quantified using 2,3,5-triphenyltetrazolium chloride staining. Immunoprecipitation and mass spectrometry identify Ripk3 as a potential downstream effector of Zbp1. Furthermore, Zbp1 and PANoptosis-related proteins are significantly upregulated following OGD/R treatment. Zbp1 knockdown markedly reduces PANoptosis and cell injury in both models, decreases infarct volume and improves neurological outcomes in MCAO/R model mice. Conversely, Zbp1 overexpression exacerbates OGD/R-induced neuronal injury and PANoptosis in HT-22 cells. This effect is partially reversed by Ripk3 knockdown, indicating that Ripk3 mediates Zbp1-induced neuronal damage. These findings highlight Zbp1 as a promising therapeutic target in ischemic stroke and underscore the need for further research into Zbp1-mediated PANoptotic pathways to aid in the development of novel neuroprotective strategies.

To determine whether lncRNA HNF1A-AS1 affects epithelial ovarian cancer (EOC) growth and macrophage polarization through miR-214/SEMA4D, the endogenous HNF1A-AS1 and miR-214 levels in human EOC cell lines are compared with those in normal ovarian epithelial IOSE80 cells. HNF1A-AS1 is overexpressed or silenced to investigate whether HNF1A-AS1 regulates miR-214/SEMA4D in SKOV3 cells and xenograft tumors, as well as the phenotypic switching of THP-1 cells. Compared with IOSE80 cells, EOC cells present significantly higher HNF1A-AS1 level and lower miR-214 level. Fluorescence in situ hybridization reveals predominant cytoplasmic localization of HNF1A-AS1, supporting its role as a competing endogenous RNA. HNF1A-AS1 and miR-214 antagonize each other in SKOV3 cells. In vitro, HNF1A-AS1 inhibits SKOV3 apoptosis and promotes migration and invasion. HNF1A-AS1 overexpression enhances miR-214 downstream of SEMA4D/PLEXIN-B1/TIAM1/RAC signaling, but miR-214 mimics significantly reverses this effect. Compared with control tumors, xenograft tumors derived from HNF1A-AS1-overexpressing SKOV3 cells present increased tumor growth, attenuated miR-214 expression, and activated SEMA4D/PLEXIN-B1/TIAM/RAC signaling. Knockdown of HNF1A-AS1 has the opposite effects. Additionally, HNF1A-AS1 promotes M2 phenotypic switching in THP-1 cells, which could be reversed by miR-214 overexpression or SEMA4D silencing. Our study suggests that by antagonizing miR-214, HNF1A-AS1 activates the SEMA4D/PLEXIN-B1/TIAM/RAC pathway, facilitating EOC growth and potentially promoting M2 macrophage polarization in the tumor microenvironment. HNF1A-AS1 represents a compelling therapeutic target for treating EOC.

Bivalent chromatin maintains genes in low-expression, poised states in embryonic stem cells (ESCs). However, bivalent promoters correlate with the transcriptional activation of oncogenic programs in malignancies, a seemingly contradiction that remains to be resolved. Here, we identify a class of cancer-specific bivalent promoters (CSBPs) through the integration of a system-level longitudinal framework. Compared with ESCs, CSBPs are characterized by lower and narrower H3K27me3 deposition alongside abundant H3K4me3, thus permitting the persistent expression of genes critical for cancer stem cell (CSC) formation and maintenance, as exemplified by SOX9. The generation of CSBPs is essentially induced by the acquisition of H3K27me3 during cell state transition, which is mediated by specific binding of PRC2.1 and the de novo recruitment of PRC2.2. Notably, disrupting the bivalency of CSBPs significantly increases H3K4me3 levels, leading to hyperactivation of CSBPs and eventually inhibiting clonal expansion of CSCs and impairing tumorigenesis. Our study not only helps explain the puzzle of transcriptionally active bivalent genes in cancer but also provides insights into the development of therapies targeting phenotypic plasticity.

The intestinal microbiota plays critical roles in regulating immunity and inflammation through intricate interactions between microbial metabolites and diverse immune cells. Dendritic cells (DCs), the most potent professional antigen-presenting cells, are essential for sensing the complicated microbiota environment and subsequently initiating and regulating adaptive immune responses. While the commensal microbiota typically mediates DC-triggered immune tolerance and thus the maintenance of intestinal homeostasis, epithelial injury or pathogenic infection generally drives the proinflammatory function of DCs, contributing to harmful inflammation and intestinal disorders. Various microbiota metabolites (such as short-chain fatty acids, bile acids, and tryptophan derivatives) play critical roles in modulating the developmental and functional diversity of DCs through metabolic, epigenetic, or signaling reprogramming. In this review, we discuss the metabolic crosstalk between the intestinal microbiota and DCs and its pivotal function in orchestrating the balance between intestinal homeostasis and pathogenic inflammation. We also discuss future directions to better elucidate the microbiota-DC dialog in intestinal immunity and develop therapeutic approaches for manipulating the microbiota-DC axis against inflammatory disorders.