Mitigating IRI-induced CMV reactivation by targeting endothelial stress responses

Northwestern University At Chicago, Evanston IL

Investigators

Abstract

PROJECT SUMMARY Cytomegalovirus (CMV) remains the most common viral infection in kidney transplant recipients leading to significant morbidity and mortality despite preemptive and prophylactic anti-viral therapies. While anti-rejection immunosuppressive therapy is considered a significant contributing factor of increased incidence of CMV infection following kidney transplant, we show that ischemia/reperfusion injury (IRI) inherent to transplant is a main trigger to induce CMV reactivation following murine transplantation of a latently infected graft, in addition to its prominent role in delayed graft function and allograft rejection. Currently, no FDA-approved therapy is available for IRI. The goal of our research is to identify cellular and molecular targets for the development of tissue/cell-specific strategies to prevent CMV reactivation and improve transplant outcomes. Endoplasmic reticulum (ER) stress and mitochondrial (Mt) dysfunction are two interconnected adverse events incurred in IRI. Inhibition of ER stress regulates Mt function and attenuates kidney injury. Inositol-requiring enzyme-1α (IRE-1α), a main transducer of ER stress, has been implicated in CMV infection. Data from our preliminary studies demonstrate that downregulation of IRE-1α expression is associated with reduced kidney transplant IRI by deletion of its upstream mediator (e.g., TLRs/Myd88). Additionally, we show that inhibition of Mt fragmentation by knocking down dynamin-related protein1 (DRP1), a mitochondrial fission protein in ECs, reduced EC activation and graft injury. Moreover, renal endothelial cells (ECs) are the frontline responders to IRI and also a main cell type of CMV latency and reactivation, representing an appropriate target site. However, it has not been investigated whether modulating ER stress and/or Mt function in graft ECs prevents CMV reactivation. The objective of this novel study is to determine whether targeting IRE-1α and/or DRP1 attenuates IRI, thereby preventing CMV reactivation in D+/R- kidney transplant. We hypothesize that CMV reactivation is initiated by IRI-mediated aberrant IRE-1α dependent ER stress responses and DRP1 mediated Mt dysfunction in donor renal ECs that harbor the latent CMV genome. We will use a preclinical mouse model of kidney transplantation to test our hypotheses. In Aim 1, we will first investigate the role of donor-derived IRE-1α in IRI-mediated CMV reactivation in rejection-free syngeneic transplants, and then in allogeneic transplants to address influence of rejection response and in modulating donor EC transcriptome landscape. Additionally, we will investigate the role of donor derived DRP1 in transplant IRI and CMV reactivation using a similar approach. In Aim 2, we will determine the therapeutic potential of pre-operative tissue/cell-specific targeting of ER and Mt stress pathways by leveraging nanocarrier delivery platforms to mitigate kidney transplant IRI, thereby preventing CMV reactivation. Data from this study will lay the foundation for further studies in an ex-vivo perfusion system of human kidneys towards a clinically translatable pre-treatment strategy for donor organ management to mitigate IRI and reduce the risk of CMV reactivation, improving the current standard of care in solid organ transplantation.