NanoFLiR · NanoFLiR: Quantitative super-resolution mapping of the ligand-accessible receptor pool in tissue

The angiotensin II-type 1 receptor (AT1R) is a G protein-coupled receptor and a central drug target in hypertension and chronic kidney disease (CKD). Although AT1R blockers are highly effective drugs, clinical benefit often wanes, highlighting the need to identify mechanisms responsible for therapeutic failure. I hypothesize that disease-driven disorganization of local renin–angiotensin–aldosterone system (RAAS) microenvironments—specifically, changes in compartmental topology and ligand accessibility of AT1R—contributes to reduced drug responsiveness. Understanding this question has been limited due to the absence of tools that yield nanoscale, in situ maps of AT1R within tissue environment.To address this gap, I will establish NanoFLiR, a novel method that pairs photoaffinity fluorescent ligands with super-resolution nanoscopy to quantify the ligand-accessible receptor pool directly in tissue. As a technical proof-of-concept, the workflow will be established in the lab of Prof. István Katona (Indiana University) with the CB1 cannabinoid receptor (CB1R), an ideal model GPCR for studying cell type- and compartment-specific organization in tissue. In the incoming phase, I will adjust the method for AT1R and generate quantitative maps of AT1R accessibility across renal cell types, and test whether pathological kidney states reorganize AT1R and other RAAS elements at cellular and subcellular scales. The project will deliver novel photo-covalent CB1R and AT1R probes, step-by-step protocols, in situ quantitative maps of ligand-accessible receptor pools, openly shared datasets and analysis code to facilitate the application by other research groups. As an MD-PhD with clinical training, I will integrate my molecular pharmacology expertise with super-resolution microscopy and tissue-handling training, positioning me to establish an independent research group that applies quantitative GPCR mapping in disease contexts to guide novel therapies.