IDENTIFICATION OF A GENOMIC DRUG TARGET FOR KIDNEY INJURY AND THERAPEUTIC SCREENING OF NATURAL PRODUCTS DERIVED SMALL MOLECULES

Abstract

Through positional cloning, Arhgef11, a Rho guanine nucleotide exchange factor was implicated in kidney injury exhibited in the Dahl salt‐sensitive (S) rat, a model of chronic kidney disease (CKD). Previous work found that genetic knockdown of Arhgef11 in HEK293 results in reduced RhoA activity (~20%), decreased activation of Rho‐ROCK pathway (~50%), and less stress fibers (vs. control). Primary proximal tubule cells (p‐PTC) cultured from the S rat exhibit increased expression of Arhgef11, activation of Rho‐ROCK, and are more prone (vs. control) to epithelial‐mesenchymal transition (EMT), a driver of fibrosis. S rat primary vascular smooth muscle cells (VSMC) cultured from kidney microvessels (k‐VSMC) also demonstrate activation of Rho‐ROCK that corresponds with increased proliferation, migration, and apoptosis. With knowledge of the role of Arhgef11 and Rho‐ROCK pathway in CKD, we sought to evaluate natural product derived small molecules to identify those that could inhibit Arhgef11‐RhoA interaction or lead to decreased expression of Arhgef11. Using an in vitro cell culture system, several hundred natural product compounds were screened for ability to inhibit RhoA activity and expression of Arhgef11, which identified 3 compounds that are currently being characterized on ability to improve downstream EMT or VSMC phenotypes. In summary, genetic analysis of a model of CKD identified a gene/pathway involved in kidney injury that served as a genomic target to screen natural product derived small molecules that could ultimately lead to new treatment for CKD.