Research Projects

Summary of the Research Proposal: Mutations in TPRKB (a component of KEOPS complex, Kinase Endopeptidase and Other Proteins of Small size) are associated with Galloway Mowat syndrome 5 (GAMOS)1. GAMOS is characterized by a combination of early-onset steroid-resistant nephrotic syndrome (SRNS) and microcephaly leading to early death in children. Currently there are many reports with single-gene associated with steroid-resistant nephrotic syndrome (SRNS) leading to chronic kidney disease and the list continues to grow rapidly2,3. The molecular functions of TPRKB and how mutations leading to loss of podocytes are the leading cause of proteinuria in children with GAMOS 5 are largely understudied. Rationale of the Research Podocytes are responsible for blood filtration in the kidney. Podocyte loss dysfunction is one of the important key drivers for the advancement of kidney disease and eventually kidney failure4. The current proposal aimed to understand the cellular and molecular functions of the TPRKB and how its mutations lead to apoptosis of the podocytes in children with GAMOS 5. KEOPS complex intrinsically possesses the DNA binding capability and TPRKB is found to interact with PARP11. However, the genomic targets of TPRKB in podocytes and how its mutations contribute to apoptosis are completely unknown. The current proposal aims to understand the functional role of TPRKB in podocyte homeostasis and how its perturbations lead to loss of podocytes using patient derived iPSCs and organoid (kidney) models. Hypothesis TPRKB might play an important role in maintaining the functions of podocytes. iPSCs derived from patients are the best choice to model and study the molecular mechanisms associated with podocyte loss and disease progression. Scientific Objectives: 1. Characterization of iPSCs from patient (GAMOS 5) fibroblasts 2. Generating and functional characterization of podocytes from patient derived iPSCs (GAMOS 5) 3. Finding genomic localization of TPRKB in iPSC derived podocytes 4. Generation and molecular characterization of kidney organoids from patient derived iPSCs (Control vs GAMOS 5) Significance of Current Study The current proposal will fill the knowledge gap in understanding the functions of TPRKB in podocyte development and delineate how mutations are contributing to podocyte loss which in turn is associated with proteinuria and kidney failure. Patient derived iPSCs have immense power to model the disease phenotype in 2D cultures and 3D organoids to understand the novel mechanisms contributing to disease progression in a dish5. To our knowledge, this will be the first iPSCs based organoid model for Galloway Mowat syndrome to delineate the perturbed signaling mechanisms which will benefit in finding alternative treatment strategies for monogenic SRNS.