CAR T Cells Targeting Senescent Gut Cells Restore Intestinal Youth in Aging Mice
Anti-uPAR CAR T cells eliminate senescent intestinal cells, reversing and preventing age-related gut decline in mice.
Summary
Researchers at Cold Spring Harbor Laboratory found that uPAR-positive senescent cells accumulate in the aging intestine, primarily in the epithelium, and impair intestinal stem cell function. Using CAR T cells engineered to target uPAR, the team demonstrated that eliminating these cells in aged mice restored regenerative capacity, improved gut barrier function, reduced inflammation, and improved microbiome composition. Remarkably, the treatment worked both therapeutically (in already-aged mice) and prophylactically (preventing decline when given to younger mice). The CAR T cells persisted long-term and developed immune memory, suggesting durable benefits from a single treatment. These findings position anti-uPAR CAR T cell therapy as a promising immune-based senolytic strategy for combating intestinal aging.
Detailed Summary
Aging progressively erodes intestinal stem cell (ISC) function, causing increased gut permeability, dysbiosis, and chronic inflammation — collectively contributing to the high incidence of gastrointestinal disorders in older adults. While dietary and pharmacological interventions have been explored, none offer durable, targeted correction of the underlying cellular defects. This study investigated whether senescent cells expressing urokinase plasminogen activator receptor (uPAR) are a key driver of intestinal aging and whether CAR T cells can reverse or prevent this decline.
The researchers used flow cytometry, senescence-associated beta-galactosidase (SA-β-gal) staining, EdU pulse labeling, and p21 co-staining to characterize uPAR-positive cells in the proximal jejunum of young (3-month-old) and old (20-month-old) mice. They confirmed that uPAR+ cells accumulate significantly with age, are predominantly epithelial (EpCAM+/CD45−), are largely non-proliferating (~97%), and co-express p21 (~70%) and SA-β-gal (~73% overlap), firmly linking them to the senescence program. Parallel analyses in human intestinal tissue corroborated these findings, strengthening translational relevance.
Anti-uPAR CAR T cells were then administered to aged mice in two paradigms: a therapeutic arm (treatment of already-aged animals) and a prophylactic arm (treatment of middle-aged animals before significant decline). In both cases, CAR T cell treatment effectively depleted uPAR+ cells from the intestinal epithelium. This was followed by measurable improvements across multiple dimensions of intestinal health: enhanced ISC regenerative capacity (as assessed by organoid-forming efficiency and in vivo crypt proliferation), restored epithelial barrier integrity, reduced inflammatory markers consistent with decreased inflammaging, improved mucosal immune function, and beneficial shifts in gut microbiome composition.
A particularly notable finding was the long-term persistence of anti-uPAR CAR T cells and their development of immunological memory, suggesting that a single administration could yield sustained senolytic surveillance. This prophylactic efficacy — preventing age-related intestinal decline rather than merely reversing it — represents a meaningful advance over existing senolytic drugs, which require repeated dosing and carry systemic side effects.
Caveats include the study's reliance on mouse models, with direct human translation remaining unproven. The specificity of uPAR as a senescence marker in the intestine versus other tissues warrants further characterization, and the long-term safety profile of persistent CAR T cells targeting a broadly expressed antigen like uPAR requires rigorous evaluation before clinical development.
Key Findings
- uPAR+ senescent cells accumulate significantly in aging mouse and human small intestinal epithelium.
- Anti-uPAR CAR T cells deplete senescent gut epithelial cells and restore ISC regenerative function in aged mice.
- Both therapeutic and prophylactic CAR T cell treatment improved gut barrier integrity, inflammation, and microbiome composition.
- CAR T cells developed long-term memory, offering durable senolytic surveillance after a single dose.
- ~73% of SA-β-gal+ senescent intestinal cells co-expressed surface uPAR, validating it as a senescence marker in the gut.
Methodology
Mouse cohorts of young (3-month) and old (20-month) animals were used alongside human intestinal tissue samples. uPAR+ cell characterization employed flow cytometry, SA-β-gal staining, EdU pulse labeling, and p21 immunostaining. Anti-uPAR CAR T cells were tested in both therapeutic (post-aging onset) and prophylactic (pre-aging onset) treatment paradigms, with outcomes assessed across ISC function, barrier integrity, inflammation, mucosal immunity, and microbiome analysis.
Study Limitations
All primary in vivo data derive from mouse models; whether anti-uPAR CAR T cells produce equivalent benefits in humans remains to be demonstrated in clinical studies. Long-term safety of persistent CAR T cells targeting uPAR — which is expressed in multiple tissue types — requires careful evaluation. The specificity and completeness of uPAR as a senescence biomarker in the intestinal epithelium compared to other senescence markers needs further validation.
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