Engineering · Aug 2026
Probio-M9 and Genetic Senolysis Attenuate Experimental Colitis by Targeting Inflammation-Associated Cellular Senescence
By Li G, Zhao Z, Zhao F et al.
Inflammatory bowel disease (IBD), including Crohn’s disease and ulcerative colitis, is characterized by chronic intestinal inflammation and limited therapeutic options. Cellular senescence contributes to persistent inflammation through the senescence-associated secretory phenotype (SASP), suggesting that modulation of senescence may represent a novel therapeutic strategy. Here, we investigated the therapeutic effects of probiotic Lacticaseibacillus rhamnosus Probio-M9 (Probio-M9) treatment and genetic senolysis on dextran sulfate sodium (DSS)-induced colitis, using p16 Ink4a -Cre ERT2 -tdTomato (PT) mice to trace senescent cells and p16 Ink4a -Cre ERT2 -DTR-tdTomato (PD) mice to selectively eliminate p16 + cells after diphtheria toxin (DT) treatment. For metagenomic analysis, fecal DNA was evaluated to assess microbial diversity, taxonomic composition, and functional pathways. In PT mice, DSS induced colon shortening, splenomegaly, mucosal inflammation, and signal transducer and activator of transcription 3 (STAT3) activation with tdTomato + senescent cell accumulation in α-smooth muscle actin (α-SMA)-, cluster of differentiation 31 (CD31)-, platelet-derived growth factor receptor α (PDGFRα)-, and c-Kit-positive compartments. Probio-M9 alleviated these changes, reduced senescent cell burden, and suppressed SASP-associated inflammation, without altering p21 or p53 expression. Metagenomic analysis showed Probio-M9 reshaped microbial composition and metabolic pathways, including selective enrichment of beneficial taxa. In PD mice, DT-mediated senolysis reduced SASP expression, STAT3 phosphorylation, and p21 levels, while increasing p53 and adenosine monophosphate-activated protein kinase (AMPK) phosphorylation. DT intervention significantly changed inter-bacterial interaction networks. Both probiotic intervention and genetic senolysis alleviated DSS-induced colitis by reducing the accumulation of p16 + senescent cells. Furthermore, analyses of human IBD specimens and independent public transcriptomic datasets demonstrated increased senescence-associated signatures in inflamed tissues and enrichment of senescence signatures in myeloid immune cells, supporting the clinical relevance of our findings. Together, these results identify inflammation-associated cellular senescence as a therapeutic target in IBD and suggest that Probio-M9 alleviates intestinal inflammation by modulating the microbiota–metabolism–senescence axis.