Acta biochimica et biophysica Sinica最新文献

Diabetic cardiomyopathy (DCM) is a major complication of diabetes and a leading contributor to heart failure, in which cardiomyocyte senescence plays an increasingly recognized role. However, the underlying mechanisms driving this process remain poorly defined. Here, we identify the (pro)renin receptor (PRR) as a critical mediator of cardiomyocyte senescence in DCM. Using a high-fat diet and streptozotocin (STZ)-induced DCM mouse model, as well as primary cardiomyocytes exposed to high glucose and palmitic acid, we demonstrate that PRR expression is significantly upregulated in diabetic hearts and closely associated with key senescence markers, including SA-β-gal, γ-H2AX, p16, and p21. PRR overexpression exacerbates these senescence phenotypes and promotes the secretion of profibrotic senescence-associated secretory phenotype factors, contributing to increased myocardial fibrosis and cardiac dysfunction. Mechanistically, PRR stabilizes the p53 protein by inhibiting tripartite motif-containing 24 (TRIM24)-mediated ubiquitination and proteasomal degradation, thereby activating the p53-p21 axis. These findings reveal a novel role of the PRR in diabetic myocardial senescence and provide potential therapeutic targets for attenuating DCM progression.

CD19-directed chimeric antigen receptor T (CAR-T) cell therapy is promising for treating relapsed/refractory diffuse large B-cell lymphoma (R/R DLBCL), yet its long-term efficacy remains limited by CAR-T-cell exhaustion. Given the broad immunomodulatory activities of vitamin D, we investigate whether its active form, 1α,25(OH) ₂D ₃, enhances CAR-T-cell functionality and improves therapeutic outcomes. We demonstrate that 1α,25(OH) ₂D ₃ treatment significantly mitigates exhaustion and enhances the antitumor activity of CD19 CAR-T cells derived from both healthy donors and DLBCL patients, which is further validated in xenograft mouse models. Mechanistically, we show that 1α,25(OH) ₂D ₃ upregulates the expression of the vitamin D receptor (VDR), promoting transcriptional reprogramming associated with memory-like differentiation and downregulation of exhaustion-related genes, thereby reshaping the functional heterogeneity of CAR-T cells under tumor stimulation. Our study highlights 1α,25(OH) ₂D ₃ supplementation as a safe and accessible approach to mitigate terminal differentiation and exhaustion of CAR-T cells, offering a promising strategy to enhance the clinical efficacy of CAR-T therapy in patients with R/R DLBCL.

CD47, a cell surface transmembrane glycoprotein, is an innate immune checkpoint that suppresses phagocytic clearance. Emerging evidence suggests that CD47 has noncanonical functions. However, its involvement in chemotherapy resistance is not well understood. Our study reveals that cisplatin treatment upregulates CD47 expression across multiple cancer cell lines. Cisplatin induces the expression of CD47 through the ATM/NF-κB signaling pathway. Genetic ablation of CD47 dramatically sensitizes cancer cells to cisplatin. Mechanistically, CD47 depletion potentiates cisplatin-induced DNA damage, as demonstrated by elevated γH2AX formation and ATM phosphorylation. Knockdown of CD47 inhibits the expression of DNA repair genes ERCC1, FANCA, and BRCA2 through the ATM/NF-κB pathway. Remarkably, CD47 blockade with neutralizing antibodies recapitulates these effects, synergistically potentiating cisplatin's DNA-damaging capacity while suppressing DNA repair capacity. CD47 blockade also potentiates cisplatin's tumor inhibitory effect in vivo. These findings establish a novel mechanism whereby CD47 promotes cisplatin resistance through transcriptional regulation of DNA repair pathway, providing rationale for combining CD47-targeted therapies with conventional chemotherapy. This dual approach could simultaneously overcome immune evasion while enhancing treatment efficacy.

Lung squamous cell carcinoma (LUSC) remains a major therapeutic challenge because of its pronounced resistance to chemotherapy, particularly carboplatin. In this study, we investigate the role of SOX2, a lineage-survival oncogene, in mediating carboplatin resistance in LUSC. We demonstrate that SOX2 is highly expressed in LUSC and is significantly associated with poor prognosis. Our results show that SOX2 directly transactivates the expression of NRF2, a master regulator of cellular redox homeostasis, thereby increasing glutathione (GSH) synthesis and protecting cells from carboplatin-induced oxidative stress. Pharmacological or genetic inhibition of NRF2 effectively abrogates SOX2-mediated carboplatin resistance both in vitro and in vivo, resensitizing LUSC cells to chemotherapy. These findings highlight SOX2 as a critical redox regulator that modulates NRF2 signaling to promote carboplatin resistance in LUSC. The identification of the SOX2-NRF2 axis as a potential therapeutic target suggests that NRF2 inhibition may represent a promising strategy to overcome chemoresistance in LUSC.

Ferroptosis, an iron-dependent form of regulated cell death, is characterized by excessive reactive oxygen species (ROS) accumulation and lipid peroxidation of polyunsaturated fatty acids (PUFAs) in cellular membranes. Non-small cell lung cancer (NSCLC) harboring KRAS mutations often exhibits therapeutic resistance but may display high susceptibility to ferroptosis. Eupalinolide B (EB), a natural compound with documented anti-cancer activity, has not been thoroughly explored for its ferroptosis-inducing potential in KRAS-mutant NSCLC. In this study, we demonstrate that EB treatment significantly elevates ROS levels, intracellular iron accumulation, and lipid peroxidation in KRAS-mutant NSCLC cells, resulting in ferroptotic cell death. Molecular docking and cellular thermal shift assays reveal that EB directly binds to and activates heme oxygenase-1 (HO-1), a critical component of the Kelch-like ECH-associated protein 1 (Keap1)-Nrf2/HO-1 oxidative stress response pathway. Genetic or pharmacological inhibition of HO-1 attenuates EB-induced ferroptosis, underscoring the pivotal role of HO-1-mediated oxidative stress in this process. Furthermore, in vivo studies using KRAS-mutant H358 xenograft models confirm the potent anti-tumor effects of EB. Collectively, our findings establish that EB triggers ferroptosis in KRAS-mutant NSCLC by activating the Keap1-Nrf2/HO-1 pathway, suggesting a promising therapeutic strategy for this challenging malignancy.

Sepsis-induced cardiomyopathy (SIC) is a severe complication of sepsis and septic shock and is characterized by cardiac dysfunction. Levosimendan (LEVO), a calcium sensitizer, has shown therapeutic potential in SIC, although its underlying mechanism remains unclear. Nrf2, a pivotal regulator of antioxidant and anti-inflammatory responses, may represent a potential target for SIC treatment. In this study, we examine the effects of LEVO on SIC and explore the mechanistic role of Nrf2 in mediating its cardioprotective effects. A murine SIC model is established via cecal ligation and puncture (CLP), and cardiomyocyte injury is induced in vitro via lipopolysaccharide (LPS) exposure in HL-1 cells. The CLP procedure significantly elevates serum cTnI and IL-6 levels and reduces the survival rates of mice. Echocardiographic analysis reveals impaired cardiac structure and function, accompanied by mitochondrial morphological and functional damage, in SIC mice. Interestingly, these pathological changes in SIC are markedly attenuated by LEVO treatment. Similarly, LEVO administration restores proliferative capacity; increases mitochondrial ATP, mitochondrial membrane potential (MMP) and NADH levels; and reduces ROS production and intracellular calcium overload. Notably, the protective effects of LEVO on cardiomyocyte viability and mitochondrial function are significantly diminished following Nrf2 inhibition or Nrf2 knockout (KO). Collectively, these findings demonstrate that LEVO mitigates cardiomyocyte injury and mitochondrial dysfunction in SIC through an Nrf2-dependent mechanism.

Myocyte enhancer factor 2A (MEF2A), a transcription factor implicated in coronary artery disease, remains unexplored in vascular redox regulation. To address this gap and overcome the limitations of current antioxidant therapies, we investigate the role of MEF2A in oxidative defense via human umbilical vein endothelial cells (HUVECs) and murine models. Adenoviral vectors encoding MEF2A-specific shRNAs or mRNAs are used to silence or overexpress MEF2A in HUVECs. For in vivo validation, endothelial-targeted MEF2A knockdown is achieved via AAV1-shRNA delivery in mice fed with a high-fat diet. Systemic redox status is assessed by measuring reactive oxygen species (ROS), glutathione homeostasis (GSH/GSSG ratio), the NADH/NAD ⁺ balance, the mitochondrial membrane potential (ΔΨm), and 8-hydroxy-2'-deoxyguanosine (8-OHdG). Mechanistic insights are derived from immunofluorescence, qPCR, western blotting, and dual-luciferase reporter assays. MEF2A silencing induces redox imbalance, characterized by elevated ROS, a reduced GSH/GSSG ratio, and ΔΨm collapse. Conversely, MEF2A overexpression synergizes with SIRT1 to restore the glutathione pool, maintain NAD ⁺ homeostasis, and suppress ROS under oxidative stress. Chromatin immunoprecipitation confirms that MEF2A directly binds to two cis-elements in the SIRT1 promoter, driving transcriptional activation. In vivo, MEF2A-deficient mice present increased vascular oxidative damage, as indicated by elevated DNA damage marker (8-OHdG) and ROS levels. The downregulation of SIRT1/PGC-1α in MEF2A-silenced cells is verified in vivo. Our findings establish MEF2A as a master regulator of endothelial redox defense via the SIRT1-PGC-1α axis, providing a mechanistic foundation for the treatment of oxidative cardiovascular disorders. This work suggests that pharmacological MEF2A activation is a novel strategy for precision antioxidant therapy in vascular medicine.

Glycolysis provides the main energy source for the rapid proliferation and migration of colorectal cancer (CRC) cells. In our previous studies, we reported that SUN5, a nuclear membrane protein, promotes proliferation and migration. However, whether SUN5 is involved in the process of glycolysis is unclear. Here, we demonstrate that overexpression of SUN5 enhances glucose uptake and lactate production in CRC cells, whereas the opposite results are observed in SUN5-knockdown cells. Mechanistically, SUN5 activates the NF-κB signaling pathway, which can be inhibited by the IKK inhibitor BAY11-7082. Further studies reveal that SUN5 interacts with TRIM28 to increase IκB α ubiquitination, leading to the nuclear translocation of phosphorylated P65 (phos-P65) and subsequent increases in the transcription of GLUT1 and LDHA, accelerating glycolysis. Moreover, xenograft transplantation experiments reveal that the knockdown of SUN5 inhibits glycolysis and tumorigenesis in vivo. Taken together, these findings indicate that SUN5 enhances the glycolysis and tumorigenesis of CRC cells via interaction with TRIM28, which provides a potential target for the diagnosis and treatment of CRC.

Spatial biology aims to elucidate cellular organization, function, and interactions within native tissue contexts, offering key insights into both normal physiology and disease. Spatial proteomics complements this by enabling high-resolution mapping of protein localization and abundance, directly reflecting functional cellular states. Unlike transcriptomics, which infers potential activity, proteomics captures actual molecular functions, including post-translational modifications and dynamic interactions. However, in situ protein profiling poses significant challenges, as proteins cannot be directly sequenced or easily targeted via nucleic acid hybridization. Antibody-oligonucleotide conjugates (AOCs) address this limitation by converting protein recognition into a DNA-based readout, thereby enabling sensitive and scalable detection. In this review, we outline the core principles of AOC-based spatial proteomic technologies, including multiplexed protein analysis, in situ protein-protein interactions, and integration with other biomolecular data. We highlight their applications in decoding tissue complexity and disease pathology and examine key technical challenges that remain. Overall, AOCs offer distinct advantages, including DNA-mediated signal amplification, spatially resolved proteomic profiling, and compatibility with multi-omics approaches, positioning them as powerful platforms in the advancement of spatial biology.

Emerging studies have revealed that disruptions in circadian crosstalk between the gut microbiota and the host play an essential role in the pathogenesis of metabolic disorders. Under physiological conditions, host circadian clocks regulate microbial diurnal oscillations through rhythmic behaviors, including feeding patterns and sleep-wake cycles. This temporal regulation manifests as robust 24-hour oscillations in microbial community composition, spatial organization, and metabolic activity. These rhythmic microbial signals and their metabolic outputs are subsequently translated into host immune modulation, establishing a bidirectional temporal dialogue between the host and microbiota. Modern lifestyle disruptions, including erratic eating patterns and shift work, desynchronize this temporal dialogue, leading to the loss of microbial rhythms, impaired intestinal barrier function, maladaptive immune responses, chronic inflammation, and systemic metabolic dysregulation. This review delineates the mechanisms through which host-microbiota circadian crosstalk governs immunometabolic homeostasis, provides a mechanistic framework for understanding immunometabolic diseases, and highlights therapeutic strategies that target microbial rhythms to reset host immunity and metabolism.