生物学最新文献

Adenomyosis (AM) is an estrogen-dependent gynecological disorder in which local steroid handling may contribute to clinical heterogeneity. To characterize estrogen metabolic features in AM, we used liquid chromatography-tandem mass spectrometry (LC-MS/MS) to quantify 13 estrogens and estrogen metabolites in endometrial tissue and serum. Tissue metabolite profiles showed marked increases in catechol estrogens, particularly 2-hydroxyestrone (2-OHE1) and 4-hydroxyestrone (4-OHE1), whereas serum changes were more limited, with 2-methoxyestrone (2-MeOE1) representing the main circulating difference. Pathway- and ratio-based analyses indicated enhanced hydroxylation in tissue without a proportionate increase in downstream methylation-related readouts. Correlation and regression analyses further showed that tissue 2-OHE1 and 4-OHE1 were independently associated with dysmenorrhea severity. In exploratory receiver operating characteristic analyses performed within the discovery cohort, tissue catechol estrogens showed stronger discriminatory ability than serum metabolites. These findings suggested that AM was associated with endometrial tissue-predominant remodeling of estrogen metabolism rather than with generalized elevation of parent estrogens. The present study identified candidate metabolic markers requiring further validation and provided a framework for future investigation of local steroid metabolism in AM.

Background: Ferroptosis induction is a promising triple-negative breast cancer (TNBC) therapy, but current inducers are suboptimal. Nitazoxanide (NTZ), an FDA-approved antiparasitic with anticancer and redox activity, may be repurposed as a ferroptosis inducer, yet its effects and mechanisms in TNBC are unclear.

Methods: Anti-TNBC effects of NTZ were assessed in MDA-MB-231 and Hs578T cells via viability, clonogenicity, migration/invasion, and zebrafish xenografts. Ferroptosis was evaluated by iron levels, lipid peroxidation, GSH/GSSG, MDA, ROS, and mitochondrial TEM. Mechanisms were studied by docking, western blot, qPCR, apoptosis assay, cycloheximide chase, and pharmacological rescue.

Results: NTZ inhibited proliferation, migration, and invasion in vitro and tumor growth in vivo, and induced ferroptosis. Mechanistically, it disrupted iron homeostasis by upregulating TFR1 and downregulating FPN1, causing iron overload and lipid peroxidation, and promoted β-catenin degradation, which transcriptionally suppressed GPX4, weakening antioxidant defense. Both β-catenin stabilization and ferroptosis inhibition reversed these effects.

Conclusion: NTZ is repurposed as a ferroptosis inducer for TNBC via dual disruption of iron homeostasis and β-catenin/GPX4 axis, providing a strong preclinical rationale for its therapeutic use.

This study examines competition models based on the Lotka-Volterra form that incorporate starvation-driven diffusions (SDD). Such dispersal assumes that species disperse in response to resource abundance or scarcity in a heterogeneous habitat. The primary objective of this study is to examine how SDD, in combination with diverse interspecific interactions, affects species' fitness and coexistence states. To this end, the study introduces a refined classification for competing interactions based on a novel metric that quantifies the variability of resource heterogeneity across the environment. This approach contrasts with traditional models that assume uniform diffusion within homogeneous environments. This study investigates the local stability of two semitrivial steady states and establishes the existence and uniqueness of positive steady states by eigenvalue analysis and monotone dynamical systems theory. Through this analytical exploration, the study reveals that the interplay between species' dispersal strategies and the varying intensities of interspecific competition significantly impacts ecological outcomes.

This work examines the dynamics of a discrete-time plankton interaction model, in which phytoplankton generate toxins and are vulnerable to external contamination. The model includes a Holling Type-II predation response and uses a piecewise constant argument approach to break it up into smaller pieces. This keeps the ecological realism of the continuous system while making it possible to study complex discrete-time behaviors. Our focus is on the formation of Neimark-Sacker bifurcation, a phenomena associated with the initiation of quasi-periodic oscillations in population densities. We show how toxin buildup and outside contamination can make plankton populations unstable, which could cause blooms to happen in an irregular way, using stability analysis and numerical simulations. The results show how useful discrete-time models are for capturing rapid changes in ecosystems, such damaging algal blooms. They also give ideas for managing ecosystems and reducing blooms.

Proper adjustment for population substructure is essential in epigenome-wide association studies (EWAS), particularly in cohorts with diverse ancestries. EPISTRUCTURE offers a genotype-free approach to ancestry inference, originally developed using a European reference population from the Cooperative Health Research in the Region of Augsburg (KORA) study. However, its effectiveness in genetically diverse, multi-ancestry cohorts remains insufficiently evaluated. For EWAS using cord-blood samples from the Hyperglycemia and Adverse Pregnancy Outcome (HAPO) study, we systematically assessed the ancestry adjustment performance of EPISTRUCTURE principal components (PCs) derived from the widely used KORA-based reference set versus new reference sets generated from genotyping data of the multi-ancestry HAPO cohort. HAPO-based reference sets were defined by varying SNP - CpG $R^2$ thresholds (e.g. RS30: $R^2>0.3$) to identify ancestry-informative CpGs. We applied these reference sets for population substructure adjustment in EWAS of three newborn adiposity traits, birthweight, cord C-peptide, and sum of skinfolds, to evaluate their impact on association detection and biological interpretation. Compared to the KORA reference, the HAPO RS30 reference consistently produced lower genomic inflation and identified more biologically relevant associations for birthweight and cord blood C-peptide in EWAS of HAPO cord blood samples (n = 3,116). Pathway enrichment analyses revealed strong immune and metabolic signals, including pathways uniquely captured by EWAS when using the HAPO-derived reference for ancestry adjustment. Trait enrichment using the EWAS Catalog further confirmed associations with fetal growth, maternal metabolic traits, and glucose regulation. Our findings demonstrate that reference sets derived from multi-ancestry cohorts like HAPO better capture underlying population substructure and improve ancestry adjustment in diverse EWAS settings.

Chronic kidney disease (CKD) stage 5 is frequently accompanied by systemic inflammation, and peripheral blood mononuclear cells (PBMCs) play an important role. To define the epitranscriptomic features of PBMC small RNAs in CKD stage 5, we profiled N6-methyladenosine (m6A) using small RNA modification microarrays. A total of 158 miRNAs, 149 pre-miRNAs, and 197 tsRNAs showed differential m6A modification. Enrichment analysis implicated PI3K-Akt, p53 signalling, and leukocyte transendothelial migration. Integrating target prediction with GEO transcriptomic datasets identified IRF1 and RUNX2 as key targets. MeRIP confirmed reduced m6A in miR-205-3p and miR-93-5p, accompanied by upregulation of RUNX2 and downregulation of IRF1 by qPCR. These results define an altered m6A-modification profile of PBMC small RNAs in CKD stage 5 and highlight miRNA-target gene axes with potential biomarker utility.

Objectives: Sepsis is a life-threatening condition driven by a dysregulated immune response to infection, yet therapeutic options beyond antibiotics and vasopressors remain limited. Neutrophil extracellular traps (NETs) contribute significantly to sepsis-induced tissue injury, and NETosis inhibition has emerged as a potential therapeutic strategy. We hypothesized that the endogenous metabolite bilirubin mitigates inflammation in sepsis by inhibiting NETosis through targeting NOX2.

Methods: Two murine sepsis models were used to assess the effects of bilirubin on survival and systemic NETosis. Plasma NET biomarkers were quantified, and primary human neutrophils were used to validate the NETosis-inhibitory activity of bilirubin in vitro. Mechanistic studies included ROS measurements, NOX2 loop C mutational analysis, and inhibition of endocytosis and autophagy to examine how bilirubin modulates NOX2 stability.

Results: Bilirubin improved survival and reduced NET biomarkers in both models. It inhibited NETosis in human neutrophils by suppressing ROS-dependent NETosis and promoting the internalization and degradation of NOX2 via endocytosis and autophagy.

Discussion: These findings identify bilirubin as an endogenous inhibitor of NETosis. By targeting NOX2 and suppressing NETosis, bilirubin may represent a promising therapeutic candidate for sepsis management.

Porcine deltacoronavirus (PDCoV) is an emerging enteric pathogen that poses a significant threat to the global swine industry and carries a potential public health risk. The development of neutralizing monoclonal antibodies (mAbs) is crucial for preventing and controlling PDCoV. However, research on neutralizing linear epitopes within the PDCoV receptor-binding domain (RBD) and the establishment of serological assays based on such mAbs remains limited. In this study, we generated two neutralizing mAbs, 1C12 and 3A11, targeting the PDCoV RBD. Epitope mapping revealed that 1C12 recognizes a linear epitope (³¹⁶DFGEARLD³²³), whereas 3A11 binds to a conformational epitope. Further residue analysis identified Arg321 as the most critical residue for binding to 1C12. Additionally, the integrity of the entire ³²¹RLD³²³ motif was found to be indispensable for the conformational recognition by mAb 3A11. Using these mAbs, we developed two blocking enzyme-linked immunosorbent assay (bELISA) methods (bELISA-1C12 and bELISA-3A11). Evaluation of 150 clinical samples demonstrated that bELISA-1C12 exhibited 93.3% concordance with a virus neutralization test (VNT), indicating higher diagnostic sensitivity than bELISA-3A11 (92.7%). A large-scale serosurvey of pig populations across ten Chinese provinces in 2025, conducted using bELISA-1C12, revealed a PDCoV seropositivity rate of 13.6%. Notably, when extending the serological screening to 21 additional animal species, we detected PDCoV antibodies in peafowl serum for the first time, suggesting possible exposure to the virus. This study identifies key antigenic epitopes on the PDCoV RBD and provides valuable tools for epidemiological surveillance and assessing the transmission risk of PDCoV.