Mechanisms of non-HIV Collapsing Glomerulopathy in Hispanic Patients - Abstract Non-HIV collapsing glomerulopathy (CG) is a severe form of glomerular disease seen in all parts of the world. Major etiological factors include circulating proteins that cause recurrent CG, infections like SARS-CoV-2 and Parvovirus B19, drugs like pamidronate, and background genomic changes potentially present in any of the preceding categories. Whereas variants of the APOL1 gene have been implicated in select populations with West African heritage, a genomic basis in other patient populations has not been elucidated. Using data from two decades of investigations into CG centered around Hispanic patients from Mexico City and more recent genomic data from Peruvian Hispanic patients, several novel mechanistic rat and mouse models of CG were developed. Critical components of the CG upstream pathways are the podocyte expressed transcriptional factor ZHX2 and glomerular integrins, including α3β1 in the podocyte, αvβ5 in the glomerular endothelium, and αvβ3 at both locations. Finally, recombinant mutated human Angiopoietin-like 4 protein 8520 is known to have an integrin stabilizing effect specific to Integrins β1 and β5, and could be potentially used to treat CG in the future. The overall premise of this application is that high podocyte ZHX2 expression and low glomerular endothelial Integrin β5 expression predispose to the development of CG. In Aim 1, changes in glomeruli with high podocyte ZHX2 expression will be investigated using transgenic rat models. Disease mechanism during the development of CG and just prior to the collapse of capillary loops will be elucidated. In Aim 2, changes in glomeruli with low endothelial Integrin β5 expression will be investigated using knockout mouse models. Disease mechanism during the development of CG and just prior to the collapse of capillary loops will be elucidated. In Aim 3, rat and mouse models of CG will be treated with protein 8520 to test for prevention or improvement in CG, and to potentially halt the disease process before the development of collapse.
