Acta biochimica et biophysica Sinica最新文献

Carfilzomib (Cfz) is a second-generation proteasome inhibitor approved for the treatment of relapsed/refractory multiple myeloma (RRMM). Previous studies have shown that Cfz is associated with a higher incidence of severe adverse cardiac effects than bortezomib (Btz); however, the underlying mechanisms remain to be elucidated. The aim of this study is to identify key regulators of cardiotoxicity induced by Cfz and to investigate the mechanisms by which these factors exert their effects. We establish a mouse model of cardiac toxicity induced by Cfz and confirm the phenotype through cardiac functional analysis, morphology assessment, myocardial fibrosis, and apoptosis analysis. We subsequently perform RNA sequencing to identify differentially expressed genes (DEGs) and further validate their functions and mechanisms. We find that Cfz induces myocardial hypertrophy and myocardial injury, along with the suppression of SENP1 expression in mouse heart tissues and in vitro cultured neonatal rat cardiomyocytes. Suppression of SENP1 exacerbates Cfz-induced injury and remodeling in cardiomyocytes by directly binding to and deconjugating the SUMO1-mediated SUMOylation of the RNA helicase DDX17. This process leads to a reduction in K-48 ubiquitin-linked polyubiquitination and degradation of DDX17, resulting in increased expressions of anti-apoptotic genes and maintenance of mitochondrial homeostasis. Therefore, the overexpression of SENP1 using AAV vectors alleviates Cfz-induced cardiotoxicity in mice. In summary, our findings reveal a previously unknown role of the SENP1-DDX17 axis in protecting against cardiotoxicity induced by Cfz, providing a potential foundation for developing therapeutic strategies to mitigate cardiac side effects in the clinical management of MM patients.

Tumor cells exhibit a notable ability to adapt to constantly changing microenvironments and possess distinct metabolic traits during metastasis. This study aims to establish a melanoma lung metastasis model in mice to elucidate the metabolic mechanisms involved in early-stage metastasis prior to treatment. The male C57BL/6 mice are divided into five groups based on time intervals of 6, 24, 72, and 120 h post-injection (SKCM-M groups) of melanoma cells, as well as a normal control group (NOR group). Our results demonstrate that platelet activation mainly occurs in the initial phases of metastasis to help tumor cells survive. NMR-based metabolomics analysis of mouse lung tissues identifies distinct metabolites and pathways associated with early-stage metastasis, revealing significant alterations in energy and amino acid metabolism during tumor progression. Further analysis indicates that methylxanthine and allantoin could serve as potential biomarkers for monitoring the early progression of tumor metastasis in cancer patients, providing novel insights into early diagnostic strategies for lung metastasis.

Lung adenocarcinoma (LUAD) is currently the cancer with the highest morbidity and mortality rates in the world, and its targeted therapy, although effective, is limited in the types of targeted drugs and prone to drug resistance in treated patients. Therefore, the continuous discovery of new targeted therapeutic agents is particularly crucial for the treatment of LUAD. Here, we aim to investigate the antitumor effect of EOAI3402143 on LUAD and the potential mechanism of its action. We use flow cytometry to analyze apoptosis, transwell and colony formation assays to detect cell migration, invasion and proliferation ability; western blot, RT-qPCR and RNA-seq to analyze the signaling pathways involved in EOAI3402143; and in vivo experiments to test the therapeutic effect of EOAI3402143 on LUAD. Our results show that EOAI3402143 promotes apoptosis and inhibits the migration, invasion and proliferation of LUAD cells. Mechanistic studies reveal that EOAI3402143 inhibits the activation of the NF-κB pathway and suppresses the expression of NR4A1, which in turn inhibits the progression of LUAD. In vivo experiments reveal that EOAI3402143 has a better therapeutic effect on LUAD. These findings indicate that EOAI3402143 has significant antitumor efficacy against LUAD and is promising as a new therapeutic agent for LUAD.

The global threat posed by COVID-19 persists, largely due to the high mutability of SARS-CoV-2 and the limited availability of effective antiviral therapeutics. The nucleocapsid (N) protein of SARS-CoV-2 is an attractive drug target because of its high degree of sequence conservation and essential role in viral replication. In this study, we show that suramin, a polysulfonated antiviral compound, binds to the C-terminal domain (N-CTD) of the N protein and interferes with its interaction with RNA. Biolayer interferometry (BLI) shows that suramin has a higher binding affinity for N-CTD ( K _d, 3.30 μM) than for RNA ( K _d, 10.12 μM). Electrophoretic mobility shift assays (EMSAs) further confirms that suramin effectively displaces RNA from N-CTD. NMR titration experiments and site-directed mutagenesis identify the α1-η1 helix (residues 248-262) as the primary suramin binding region, with residues K256, R259 and R262 playing critical roles in ligand recognition. In addition, NMR relaxation and model-free analyses reveal that the α1-η1 helix is highly flexible on the picosecond to nanosecond timescale, a dynamic feature that likely facilitates ligand binding. Furthermore, ITC and EMSA experiments demonstrate that suramin can bind to the full-length N protein at multiple sites and dissociate RNA from the N protein. Taken together, these findings provide structural and biophysical insights into the mechanism of action of suramin and establish a rational basis for the development of targeted antiviral therapies against SARS-CoV-2.

Whole-genome duplication (WGD) represents an evolutionarily conserved process occurring in prokaryotes, eukaryotes, and somatic mammalian tissues. While developmentally programmed WGD supports normal tissue regeneration, unscheduled WGD drives chromosomal instability and oncogenic progression in cancer. Recent studies have clarified dual roles of WGD across physiological homeostasis and disease pathogenesis. Here, we review the prevalence of WGD, the molecular mechanisms driving its major causes and its biological consequences. In addition, we highlight recent advancements in WGD detection, including both conventional cytogenetic techniques and newly developed high-throughput sequencing approaches. The integration of multi-omics and machine learning further improves ploidy analysis, particularly in cancer research. Together, these insights establish WGD as a critical regulator of development, regeneration, and disease and underscore the importance of emerging computational and sequencing tools for its precise characterization.

Microglia/macrophage polarization is a crucial factor in inflammatory processes following ischemic stroke (IS). This study explores the molecular mechanisms through which lysine-specific histone demethylase 4 (KDM4A) regulates microglial polarization postischemic stroke. IS models are established in vivo via transient middle cerebral artery occlusion (MCAO) surgery and in vitro via oxygen-glucose deprivation (OGD) treatment. 2,3,5-Triphenyl tetrazolium chloride staining is conducted to determine the infarct size. RT-qPCR is used to determine mRNA expression. Immunofluorescence assay is used to detect the expressions of KDM4A and biomarkers of microglia. Western blot analysis is used to determine the expressions of KDM4A and serine peptidase inhibitor Kazal type 5 (SPINK5). The enrichment of H3K9me3 on the promoter of SPINK5 is determined via chromatin immunoprecipitation assay. Neuronal apoptosis is detected via TUNEL assay. We find that KDM4A is upregulated in IS models. Downregulation of KDM4A mitigates neurological dysfunction, enhances motor capacity, and reduces inflammatory infiltration in vivo while suppressing microglial activation and promoting M2 polarization. Mechanistically, KDM4A reduces the enrichment of H3K9me3 on the SPINK5 promoter, thereby increasing SPINK5 expression. Moreover, overexpression of SPINK5 inhibits M2 microglial polarization and neuronal apoptosis. Overall, KDM4A exacerbates ischemic stroke-induced brain injury by promoting proinflammatory microglial polarization via SPINK5 signaling.

Rapid identification of pathogens responsible for bloodstream infection is critical for early intervention and effective treatment. Reporter phages, which are known for their exceptional sensitivity and specificity in pathogen detection, have garnered significant interest. In this study, we systematically evaluate phage genome editing strategies that combine homologous recombination with the CRISPR-Cas9 system. We investigate the impacts of homologous arm length, sgRNA activity, target site, and plasmid interactions on editing efficiency. Our results demonstrate that successful genome editing depends on both sufficient cleavage pressure and optimal homologous arm length, particularly when using low-activity sgRNAs. On the basis of these findings, we develop a highly efficient gene editing strategy TPMSR (triple-plasmid-mediated synchronous recombination) that overcomes the limitations of conventional methods that rely on high-activity sgRNA and restricted editing sites. Using the TPMSR strategy, we integrate the Nluc gene into phage T7, generating the reporter phage T7:: Nluc, which is then incorporated into a microfluidic chip. Validation with 51 clinical isolates demonstrates outstanding sensitivity, specificity, and accuracy in detecting E. coli in blood within 1.5 h at concentrations less than 30 CFU/mL. This study presents a robust strategy for phage genome engineering and develops a promising method for the rapid diagnosis of bloodstream infections caused by Escherichia coli.

MSCs have demonstrated their unique therapeutic potential in early clinical trials for a variety of respiratory diseases in recent years, but their use in the treatment of asthma has rarely been reported. In this study, a chronic murine asthma model that is more similar to clinical asthma is constructed via sustained HDM induction for 70 days, followed by treatment via tail vein injection of MSCs after modeling. The mechanism by which MSCs alleviate airway remodeling is investigated via RNA-seq. The airways on the day following treatment are used to screen for transcriptomic changes resulting from the MSC treatment under study, filtering for differentially expressed genes (DEGs), identifying their enrichment pathways, and finally confirming the DEGs gained via western blot analysis. After HDM treatment, airway remodeling is reversed, asthma and the HIF-1 signaling pathway are inhibited, and the expression levels of Timp1 and Wnt2b in the fibrosis pathway are also significantly decreased. STRING analysis reveals a reciprocal interaction in their expression, which is also confirmed by western blot analysis. To verify whether MSCs alleviate airway remodeling by inhibiting Timp1, we construct MSCs overexpressing Timp1 and evaluate their effects in vitro and in vivo. The ability of MSCs to alleviate airway remodeling is reversed after Timp1 is overexpressed. These findings demonstrate that MSCs alleviate asthma-induced airway remodeling by inhibiting the Timp1-Wnt2b axis.