*Purpose: Allograft vasculopathy (AV) is a complication of chronic allograft rejection whose underlying mechanism(s) of etiopathogenesis are poorly defined. We examined the role of ZFYVE21, a Rab5 effector we recently identified, in the development of AV.

*Methods: Using a humanized mouse model and patient biospecimens, we employed genetic and pharmacologic approaches to examine the role of ZFYVE21 expression in T cells with regards to the formation of AV.

*Results: ZFYVE21 dysregulates a canonical wound repair pathway, Hedgehog (Hh) signaling, to promote the development of AV in human coronary arteries. Hh ligands released by endothelial cells (ECs) during ischemia reperfusion injury (IRI) generate an “Hh-responsive” subset (CD4+CD45RO+Ptch1hiPD1hi) highly expressing ZFYVE21 and displaying heightened effector and migratory responses. In Hh-responsive T cells, ZFYVE21 modulates T cell intrinsic inflammasome activity in an Akt-dependent manner to mediate IL-18-dependent potentiation of type 1 responses. This process furthers EC injury, propagating release of Hh ligands. Hh-responsive T cells, noncanonical Hh signaling, Hh-induced NLRP3 inflammasomes, and ZFYVE21 expression promote AV-like changes in a humanized mouse model. Hh-responsive T cells expressing ZFYVE21 and showing inflammasome activity are expanded in patients with IRI.

*Conclusions: Hh-induced ZFYVE21 assembles T cell intrinsic, NLRP3 inflammasomes to promote the development of allograft vasculopathy.

« Back to 2022 American Transplant Congress