PROJECT DESCRIPTION: The primary objective of this project is to demonstrate the feasibility of developing C23 as a novel and effective therapeutic for patients with ischemic acute kidney injury (AKI), a significant cause of prolonged hospitalization and mortality. Ischemic AKI often complicates hemorrhagic shock, septic shock, and surgery. Yet, despite it being a frequent, life-shortening, and costly complication, no FDA-approved drugs are currently available to treat patients with ischemic AKI. We have discovered that cold-inducible RNA-binding protein (CIRP) acts as a novel damage-associated molecular pattern (DAMP) to increase inflammation after ischemic injury. In our preliminary studies, we show that CIRP is released into the circulation after renal ischemia and reperfusion (RIR) and promotes the development of AKI. We screened CIRP-derived small peptides and identified C23 to have high affinity for the CIRP receptor and inhibit CIRP activities. We also show that administration of C23 at the beginning of reperfusion attenuates renal inflammation and damage. Administration of C23 at the time of reperfusion after ischemia also increased the seven-day survival of mice subjected to RIR from 37% to 70%. Therefore, we hypothesize that C23 can be developed as a new and effective drug to improve renal function and prevent renal damage after ischemic AKI. In this project, we will demonstrate the feasibility of developing C23 to treat ischemic AKI by determining C23?s optimal dose to improve renal function after RIR and after sepsis, C23?s therapeutic window to improve survival after RIR and after sepsis, and C23?s pharmacokinetic and safety profile in healthy animals. Our future steps of drug development (SBIR Phase II and beyond) include completing preclinical studies, establishing ADME, advanced pharmacokinetics and safety studies in healthy and diseased animals, and filing an investigational new drug (IND) application with the FDA to initiate clinical trials. Our ultimate goal is to obtain commercial utilization of C23 as a safe and effective drug for patients with ischemic AKI caused by renal hypoperfusion.