Anti-uPAR CAR T cells reverse and prevent aging-associated defects in intestinal regeneration and fitness

Intestinal stem cells (ISCs) drive the rapid regeneration of the gut epithelium. However, during aging their regenerative capacity is reduced, possibly through senescence and chronic inflammation, albeit little is known about how aging-associated dysfunction arises in the intestine. We previously identified the urokinase plasminogen activator receptor (uPAR) as a senescence-associated protein in other tissues and developed CAR T cells able to efficiently target it. Harnessing them, here, we identify the accumulation of uPAR-positive cells in the aging gut and uncover their detrimental impact on ISC function in aging. Thus, both therapeutic and prophylactic treatment with anti-uPAR CAR T cells improved barrier function, regenerative capacity, inflammation, and mucosal immune function in aged mice. Overall, these findings reveal the deleterious role of uPAR-positive cells on intestinal aging in vivo and provide proof of concept for the potential of targeted immune-based cell therapies to enhance tissue regeneration in aging organisms. Overall design: For "control" samples: Young (3 months) and old (20 months) Bl/6J mice had their intestinal crypts isolated and processed for scRNAseq. For "uPAR and UT" experiments: Young (3 months) and old (18 months) mice were treated by tail vein injection with 0.5x10^6 untransduced T cells (UT) or uPAR CAR T cells (m.uPAR-m.28z). The intestinal crypts from these mice were isolated and disociated at 6 weeks after infusion. At this time the young mice were 4.5months old and the old mice were 19.5months old.