The cathepsin-S/protease-activated receptor-(PAR)-2 axis drives chronic allograft vasculopathy and is a molecular target for therapeutic intervention.

Martin Ryll, Yutian Lei, Michael N Thomas, Mingming Li, Bernhard Renz, Ulrich Wirth, Florian Kühn, Alexandr Bazhin, Jens Werner, Hans-Joachim Anders, Joachim Andrassy

Transplant immunology 2023 Apr

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Cathepsin S (CatS) and proteinase-activated receptor (PAR)-2 are involved in the remodelling of vascular walls and neointima formation as well as in alloantigen presentation and T-cell priming. Therefore, we hypothesized that CatS/PAR-2 inhibition/deficiency would attenuate chronic allograft vasculopathy. Heterotopic aortic murine transplantation was performed from C57BL/6J donors to C57BL/6J recipients (syngeneic control group), Balb/c to C57BL/6J without treatment (allogenic control group), Balb/c to C57BL/6J with twice daily oral CatS inhibitor (allogenic treatment group) and Balb/c to Par2-/- C57BL/6J (allogenic knockout group). The recipients were sacrificed on day 28 and the grafts were harvested for histological analysis and RT-qPCR. After 28 days, mice of the allogenic control group exhibited significant neointima formation and massive CD8 T-cell infiltration into the neointima while the syngeneic control group showed negligible allograft vasculopathy. The mRNA expression level of CatS in allografts was 5-fold of those in syngeneic grafts. Neointima formation and therefore intima/media-ratio were significantly decreased in the treatment and knockout group in comparison to the allogenic control group. Mice in treatment group also displayed significantly fewer CD8 T cells in the neointima compared with allogeneic controls. Additionally, treatment with the CatS inhibitor and PAR2-deficiency decreased mRNA-levels of interleukins and cytokines. In conclusion, our data indicate that inhibiting CatS and PAR-2 deficiency led to a marked reduction of neointima formation and associated inflammation in a murine heterotopic model for allograft vasculopathy. Copyright © 2023 Elsevier B.V. All rights reserved.

Citation

Martin Ryll, Yutian Lei, Michael N Thomas, Mingming Li, Bernhard Renz, Ulrich Wirth, Florian Kühn, Alexandr Bazhin, Jens Werner, Hans-Joachim Anders, Joachim Andrassy. The cathepsin-S/protease-activated receptor-(PAR)-2 axis drives chronic allograft vasculopathy and is a molecular target for therapeutic intervention. Transplant immunology. 2023 Apr;77:101782