Targeting stress-induced senescent cells prolongs corneal allograft survival

Background: and Purpose: Allograft rejection and corneal endothelial dysfunction are the two leading causes of corneal transplantation failure, but the underlying pathogenesis remains largely uncertain. Experimental Approaches: Using murine orthotopic corneal transplantation model, we analyzed the cellular senescence of allografts at early stage after transplantation through senescence-associated β-galactosidase (SA-β-Gal) staining, real-time PCR and western blot. Genetic approach, adoptive transfer experiment, primary mouse corneal fibroblasts (MCF) culture platform, exosome purification, and various experimental readouts were performed to investigate the pathogenic roles of transplantation stress-induced senescence in driving corneal allograft rejection and the underlying mechanism. Key Results: We showed that the surgery injury evoked corneal senescence-like phenotype at early stage after age-matched transplantation, characterized by more accumulation of SA-β-Gal positive cells in corneal endothelium and stroma, and elevated senescence marker p16INK4a (CDKN2A) and p21 (CDKN1A). Through genetic approach and adoptive transfer experiment, we revealed that stress-induced senescence promoted corneal immune rejection. Mechanistically, stress-induced senescence drove the escalated alloimmune responses through senescence-associated secretory phenotype (SASP) and exosomes. Targeting senescent cell using senolytic approach significantly blocked ocular alloresponse and subsequent immune rejection. Conclusion and Implications: These findings highlighted transplantation stress-induced senescence as pathogenic driver for corneal allograft rejection, further suggesting senolytic therapy as a novel option against corneal transplantation rejection and perhaps other organ transplantation rejection.