Fibrosis induced immune exclusion is a hepatocellular carcinoma (HCC) hallmark, underscoring the key role of cancer-associated fibroblasts (CAFs) in immune regulation. Through HCC spatial multi-omics data and integrating pan-cancer scRNA-seq profiles of CAFs under immune checkpoint blockade (ICB) treatment, we characterized a potential crosstalk between capillaries and CAFs mediated by the NOTCH signaling pathway. Specifically, endothelial DLL4-NOTCH3 signaling appears to be associated with matrix-producing CAFs (mCAFs) polarization, leading to extracellular matrix remodeling and the establishment of immune-restrictive niches that hinder T cell infiltration. Perturbation of NOTCH signaling attenuated mCAF differentiation and enhanced T cell infiltration in vitro, and was associated with improved ICB response in both spontaneous and orthotopic HCC mouse models. Collectively, our findings suggest that capillary-mCAFs communication through the NOTCH pathway, particularly NOTCH3 activation, may contribute to fibrosis-driven immune exclusion in HCC. Targeting this axis could provide a promising strategy to alleviate stromal barriers and potentiate immunotherapy efficacy.

Glucocorticoid-induced myopathy is characterized by progressive muscle atrophy and impaired regeneration, yet effective microbiota-oriented interventions for preserving muscle homeostasis remain largely unexplored. Here, we demonstrate that dietary chondroitin sulfate (DCS) restores muscle mass and function through a microbiota-dependent gut–muscle metabolic axis. DCS failed to confer protection in germ-free or antibiotic-treated mice, establishing gut microbiota as a prerequisite for its efficacy. Microbiota transplantation and mono-colonization experiments identified Lactobacillus johnsonii Z-RW as a functionally relevant mediator capable of recapitulating muscle protection under controlled microbial conditions. Integrated metagenomic, metabolomic, and proteomic analyses revealed coordinated reprogramming of intestinal sugar utilization and bile acid metabolism following DCS administration. Notably, DCS promoted bile acid deconjugation and enrichment of secondary bile acids, coinciding with restoration of muscle regenerative and energetic programs, including upregulation of NMRK2, PAX7, and SIRT1. Metabolite supplementation further implicated bile acids as candidate mediators linking microbial metabolism to muscle phenotypes. To quantitatively integrate these shifts, we introduce the sugar-bile acid ratio as a systems-level descriptor of microbiota-driven metabolic remodeling. Our findings delineate a microbiota-dependent metabolic framework through which a functional polysaccharide reshapes intestinal biochemistry to influence distal muscle physiology. This work highlights bile acid-associated signaling as a central relay within the gut-muscle axis and provides a conceptual foundation for microbiota-targeted strategies to mitigate muscle wasting.

Influenza A virus (IAV) infection has a wide clinical spectrum, from mild illness to life-threatening pneumonia, yet the underlying immune determinants of disease remain poorly defined. Here, we generated a large-scale single-cell transcriptomic atlas from peripheral blood, profiling more than 612,010 cells from 97 individuals, including healthy controls, and patients with mild, severe, or convalescent IAV infection. Our findings uncovered a core immune dichotomy that determines clinical severity: a protective, monocyte-centric antiviral state in mild disease versus a pathological, neutrophil- and myeloid-derived suppressor cell (MDSC)-driven hyperinflammatory state in severe infection. Severe disease was marked by a peripheral hyperinflammatory state, driven by specific monocyte and neutrophil subsets via the S100A8/9/12–TLR4/RAGE signaling axis, and was coupled with the expansion of granulocytic MDSCs that likely contribute to T cell paralysis. In contrast, mild disease was associated with a protective, monocyte-centric response characterized by robust antiviral interferon signaling and enhanced antigen presentation. This functional divergence extends to the adaptive immune system, where mild disease was associated with CD8⁺ T cells displaying a balance of high cytotoxicity and regulated exhaustion. In severe illness, however, T cells become profoundly dysfunctional, exhibiting signatures of metabolic stress and apoptosis alongside the emergence of pathogenic, pro-inflammatory regulatory T cells. Together, our atlas provides a high-resolution immunological blueprint of human IAV infection, delineates the cellular states and pathways that govern clinical trajectories and offers a critical resource for developing host-directed therapies.

Gut microbiome alterations are increasingly associated with hepatocellular carcinoma (HCC), highlighting the gut–liver axis as a key contributor to tumor progression and prognosis. Taxon-based HCC microbiome studies have shown limited reproducibility because they are affected by database dependency, taxonomic ambiguity, and overlooked ecological interactions. The Two Competing Guilds (TCG) model, based on stable gut microbiome interactions, provides a structurally grounded framework for robust, generalizable biomarkers. Using shotgun metagenomic data from a newly recruited cohort of 120 surgically resectable HCC cases and 76 benign liver tumor controls, we constructed co-abundance networks to identify stably correlated genome pairs and assembled a hepatic cancer-TCG (HCC-TCG) model composed of 142 genomes. Functionally, one Guild had more genes for butyrate production from carbohydrate fermentation while the other Guild was enriched in genes for virulence factors and antibiotic resistance, highlighting its potential proinflammatory roles. Classifiers trained on the abundance profiles of HCC-TCG genomes successfully distinguished HCC from benign liver tumors (area under the receiver operating characteristic, AUROC = 0.70) and from colorectal liver metastases (CRLM) (AUROC = 0.78). In an external validation cohort, the model further discriminated against HCC from intrahepatic cholangiocarcinoma (iCCA) (AUROC = 0.72), and from healthy controls (AUROC = 0.79–0.85), demonstrating its broad applicability for tumor stratification across clinical contexts. Moreover, HCC-TCG profiles predicted post-resection recurrence risk and response to adjuvant therapies (AUROC up to 0.83). Importantly, external validation in two independent cohorts of advanced HCC patients treated with PD-1/PD-L1 inhibitors demonstrated consistent predictive performance (AUROC = 0.64–0.73), confirming the model's generalizability in nonsurgical and immunotherapy contexts. This genome-specific, ecologically structured, and database-independent framework identifies a conserved Guild-based microbiome signature for HCC. Our findings demonstrate that a fixed genome-resolved ecological structure retains transferable discriminatory signal across clinical contexts. The HCC-TCG framework provides a genome-specific, interaction-based foundation for future development of non-invasive microbiome stratification strategies requiring prospective validation.