Acta biochimica et biophysica Sinica最新文献

Metabolic diseases, which include obesity, type 2 diabetes, atherosclerosis, and metabolic dysfunction-associated steatotic liver disease (MASLD), are significant global health challenges. Patients with these conditions frequently exhibit gut dysbiosis and compromised gut barrier integrity, which lead to excessive translocation of Gram-negative bacterial lipopolysaccharide (LPS or endotoxin) from the gut lumen into the systemic circulation. This results in chronically elevated systemic LPS levels, a condition termed "metabolic endotoxemia". Gut-derived LPS may stimulate inflammatory responses and oxidative stress when it translocates and is recognized by host Toll-like receptor 4 (TLR4) and caspase-4/-5/-11. Metabolic endotoxemia is a primary trigger for the low-grade inflammation that promotes the development of metabolic diseases. Emerging evidence also indicates that metabolic endotoxemia acts as a key driver in the pathogenesis of neurodegenerative disorders, such as Alzheimer's disease, by promoting chronic neuroinflammation. In this review, we discuss: (1) the molecular structure of LPS that determines its bioactivity and its recognition by host cells, (2) host regulation of its bioactivity, (3) its translocation from the gut lumen into the systemic circulation, and (4) how metabolic endotoxemia contributes to obesity, type 2 diabetes, atherosclerosis, MASLD, and Alzheimer's disease. We conclude by exploring potential interventions aimed at preventing or mitigating metabolic endotoxemia by promoting LPS degradation and inactivation.

Monocyte-derived macrophages (mo-macs) are central regulators of innate immunity and are essential for maintaining physiological homeostasis and host defense. Their functional efficacy relies on precisely coordinated transendothelial migration (TEM) and phenotypic polarization into classically activated (M1) or alternatively activated (M2) macrophages. This review delineates how cell adhesion molecules (CAMs), including integrins, selectins, the immunoglobulin superfamily (IgSF), and cadherins, act as pivotal sensors that orchestrate these spatiotemporal dynamics. CAMs facilitate the multi-step TEM of mo-macs and trigger intracellular signaling pathways, such as nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and signal transducer and activator of transcription (STAT), to dictate macrophage plasticity in response to inflammation and the tumor microenvironment (TME). We highlight the dual role of CAMs in driving the pathogenesis of atherosclerosis and cancer while also exploring their potential in bioengineering for regenerative medicine. Elucidating these CAM-dependent regulatory networks not only helps to explain the intrinsic mechanisms underlying immune regulation but also provides a theoretical framework for designing next-generation targeted immunotherapies and personalized clinical interventions for inflammatory diseases and malignancies.

Ciclopirox (CPX), an FDA-approved antifungal drug, exhibits promising antitumor activity. This study investigates its efficacy and mechanisms against melanoma. Here, we find that CPX potently inhibits melanoma cell proliferation, migration, and invasion in vitro and significantly suppresses xenograft tumor growth in vivo (20 mg/kg body weight, i.p.). Mechanistically, CPX induces mitochondrial dysfunction and a reactive oxygen species burst, activating PERK-dependent endoplasmic reticulum stress and ultimately triggering apoptosis via Caspase-3 activation. This apoptotic process is rescued by the antioxidant N-acetylcysteine, supporting a causative role of oxidative stress in CPX-induced cytotoxicity. Furthermore, CPX directly binds to the Src kinase domain, inhibiting its autophosphorylation and subsequently mediating a concentration-dependent reduction in STAT3 phosphorylation at Tyr705. It also downregulates total STAT3 protein levels and Ser727 phosphorylation, indicating multi-level disruption of STAT3 signaling. In conclusion, our findings reveal that CPX suppresses melanoma through dual mechanisms: activating ROS/ER stress-mediated apoptosis and disrupting the Src/STAT3 signaling pathway, supporting its therapeutic repurposing for melanoma.

Benzylisoquinoline alkaloids (BIAs) represent a class of plant-derived compounds with significant pharmacological importance. The biosynthesis of most BIAs originates from a common precursor ( S)-reticuline. ( S)- N-methylcoclaurine 3'-hydroxylase (NMCH), encoded by CYP80B members, has always been regarded as a rate-limiting step that restricts the efficient synthesis of ( S)-reticuline, thereby leading to the low accumulation of BIAs. The highly-efficiency NMCH still needs to be further explored. Species within the Berberidaceae family are known to accumulate diverse BIAs at relatively high levels, making them an ideal plant resource for exploring highly active enzymes involved in BIA synthesis. Here, by integrating transcriptome and metabolite analysis across 11 Berberidaceae plants, we mine and characterize candidate genes involved in ( S)-reticuline biosynthesis. We further establish an engineered yeast platform for functional screening of NMCH genes and evaluate the catalytic activity of all CYP80B candidates. Among these, MbNMCH, isolated from Mahonia bealei, exhibits significantly higher catalytic activity for ( S)-reticuline production in yeast compared to previously reported NMCH enzymes. Our findings provide abundant genetic and metabolic information on Berberidaceae plants and identify a highly efficient enzymatic tool for BIA production in microbial cell factories, facilitating the sustainable manufacturing of diverse valuable alkaloids.

Sepsis-induced cardiomyopathy (SICM) is a life-threatening complication of sepsis characterized by acute and reversible myocardial dysfunction, for which effective targeted therapies remain limited. Artesunate (ART), a well-established first-line antimalarial agent, has attracted increasing attention for its anti-inflammatory, antioxidant, and cytoprotective properties. However, its role in SICM has not been fully elucidated. In this study, a murine SICM model is established using lipopolysaccharide (LPS) to evaluate the effects of ART on animal mortality, cardiac function, histopathology, and biomarkers of myocardial injury. In parallel, the in vitro study is performed using neonatal rat cardiomyocytes and H9c2 cells exposed to LPS in the presence or absence of ART. Transcriptomic and metabolomic analyses are used to elucidate the molecular mechanisms underlying ART-mediated cardioprotection. ART administration significantly improves cardiac function, attenuates myocardial injury, alleviates the inflammatory response, and reduces cardiomyocyte apoptosis in LPS-challenged mice. Consistent results are observed in vitro. Integrated multi-omics analyses identify the Akt/FoxO3 signaling pathway as a critical target of ART. ART treatment contributes to increased Akt phosphorylation and subsequent suppression of FoxO3 nuclear translocation and its transcriptional activity. Pharmacological inhibition of Akt using MK2206 or genetic knockdown of FoxO3 by siRNA abolishes the cardioprotective effects of ART. In addition, molecular docking analysis suggests a potential interaction between ART and Akt isoforms. Collectively, these findings demonstrate that ART possesses significant cardioprotective effects in experimental SICM through modulation of the Akt/FoxO3 signaling axis, leading to reduced apoptosis and inflammation. ART may serve as a therapeutic candidate for the management of SICM.

Severe pneumonia remains a major contributor to infection-related deaths globally, often driven by inadequate pathogen clearance. Impaired immune cell trafficking to infected sites critically contributes to this outcome, yet the underlying regulatory mechanisms remain incompletely understood. Here, we analyze peripheral blood transcriptomic data from a public cohort of 184 pneumonia patients to identify prognosis-related genes, followed by prospective enrollment of 38 patients for integrated multi-omics profiling. Low CX3CR1 expression is associated with 28-day mortality and correlates with hypermethylation at the promoter CpG site cg00262061. Mechanistically, this methylation modification impedes RNA polymerase II recruitment to the CX3CR1 promoter, thereby suppressing transcription. CRISPR-dCas9-based targeted methylation or demethylation at cg00262061 in primary human CD14+ monocytes directly manipulates endogenous CX3CR1 expression, establishing causality. Notably, cg00262061 hypermethylation is detected exclusively in the CX3CR1- subset of patient peripheral blood mononuclear cells, indicating selective epigenetic silencing. Functionally, this methylation or direct CX3CR1 knockdown markedly impairs monocyte and T cell migration. In a murine bacterial pneumonia model, systemic CX3CR1 inhibition reduces pulmonary immune cell infiltration, increases bacterial burden, exacerbates lung injury, and decreases survival. Competitive adoptive transfer confirms a cell-intrinsic migration defect of CX3CR1-deficient immune cells. These findings delineate a pathogenic pathway wherein promoter hypermethylation silences CX3CR1, compromises immune cell homing, and aggravates disease severity, offering a mechanistic basis for prognostic assessment and a conceptual framework for host-directed therapies, although clinical translation warrants further investigation.

Microglia-mediated neuroinflammation has emerged as a potential therapeutic target for neuropathic pain. T-cell immunoglobulin domain and mucin domain-3 (TIM3), which is expressed on various immune cells, has been implicated in inflammation-related diseases. However, its role in neuropathic pain remains unclear. Here, we show that following chronic constriction injury, TIM3 expression is significantly upregulated and plays a protective role by limiting the development and progression of neuropathic pain. Specifically, TIM3 upregulation attenuates neuropathic pain progression and microglia-mediated neuroinflammation, whereas pharmacological inhibition of TIM3 exacerbates pain hypersensitivity. Mechanistically, TIM3 negatively regulates glycolysis, thereby suppressing NOD-, LRR-, and pyrin domain-containing protein 3 (NLRP3) inflammasome activation and preventing further microglia-driven inflammatory responses in vivo and in vitro. Furthermore, both glycolysis and the glycolysis-associated NLRP3 inflammasome are essential for TIM3-mediated neuropathic pain development. Additionally, TIM3 inhibits nuclear factor-kappa B (NF-κB) activation by downregulating glycolysis in vivo and in vitro. Our findings identify TIM3 as a negative regulator of the glycolysis/NLRP3 inflammasome pathway in inflammatory microglia, highlighting its protective role against neuropathic pain. These results suggest that TIM3 is a promising therapeutic target for preventing neuropathic pain.

Reperfusion therapy is critical for acute myocardial infarction but is often accompanied by myocardial ischemia/reperfusion injury (MIRI). Phillyrin, a natural lignan from Forsythia suspensa, exerts anti-inflammatory and antioxidant effects; however, its role and mechanism in MIRI remain unclear. In this study, HL-1 cardiomyocytes are subjected to oxygen-glucose deprivation/reperfusion (OGD/R). Cell viability, apoptosis, oxidative stress, and inflammation are measured after phillyrin treatment. Multiomics (mRNA-seq, proteomics, and acetylproteomics) is used to identify key targets and pathways. Molecular docking, co-immunoprecipitation, site-directed mutagenesis, and western blot analysis are used to validate posttranslational regulation. A mouse MIRI model is established to confirm the in vivo cardioprotective effects of phillyrin. Phillyrin preserves cell viability and reduces apoptosis, oxidative stress, and inflammation in OGD/R-injured HL-1 cells. Multiomics integration reveals that phillyrin acts primarily through posttranslational regulation and highlights kinetochore scaffold 1 (KNL1) as the only protein that is both upregulated and hyperacetylated at lysine 605 (K605). Mechanistically, phillyrin may bind to the KNL1 C-terminus and enhance the interaction between KNL1 and acetyltransferase p300/CBP. KNL1 K605R mutation and Knl1 knockdown reduce KNL1 protein expression and reverse the inhibitory effects of phillyrin on p53 pathway-mediated apoptosis, oxidative stress, and inflammation. In mouse MIRI models, phillyrin reduces infarct size, myocardial damage, and cardiomyocyte apoptosis; these effects are abolished by knockdown of Knl1. Therefore, phillyrin promotes KNL1 acetylation at K605 to increase KNL1 protein expression, thereby inhibiting p53 signaling and alleviating apoptosis, oxidative stress, and inflammation in MIRI. This study identifies KNL1 acetylation at K605 as a novel posttranslational modification target for cardioprotection.