Delineating Determinants of Renal Tubulogenesis in an ECM-based Co-culture Model

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 DESCRIPTION (provided by applicant): Chronic kidney disease is a significant and growing health problem in the United States. Patients who suffer from end-stage renal disease require renal replacement therapy in the form of either dialysis or kidney transplantation. Although kidney transplantation leads to superior patient outcomes and is more cost effective than dialysis, the severe shortage of transplantable donor kidneys limits the ability of clinicians to extend this therapy to all patients in need. One approach to overcoming the kidney shortage would be to combine recent advances in tissue engineering, regenerative medicine, and stem cell science to develop laboratory-grown, bioartificial organs. Non-transplantable kidneys that have been stripped of their cellular component, or decellularized, could be repopulated with patient-specific stem cells to generate an immunologically compatible kidney graft on demand. While kidney decellularization has been demonstrated as technically feasible, at present there is a limited understanding of the role the renal extracellular matrix (ECM) plays in regulating homing of parenchymal cells to particular niches of the kidney, and their subsequent organization into mature components of the nephron. Additionally, it is unclear how interactions between tubular epithelial cells and other resident support cells following acute injury contribute to either proper tissue regeneration or pathological development of renal fibrosis, a significant cause of kidney damage leading to renal failure. It is therefore our aim to study the process of tubule regeneration ex vivo using decellularized rat kidneys as a three-dimensional, biomimetic whole-organ culture system. While working toward the long-term goal of engineering a functional nephron, we seek to learn more about the physiological factors that govern appropriate tubule regeneration by seeding the renal ECM with select populations of epithelial cells and stromal cells. We hypothesize that induction of ischemic reperfusion injury ex vivo following the development of tubules within decellularized renal matrices will create a regenerative state, by which we can study interactions between tubular epithelial cells and human cadaver-derived renal repair cells or stromal fibroblasts. To test this hypothesis, we will use perfusion bioreactors to create a temporary hypoxic state in recellularized kidney scaffolds, by limiting perfusion of oxygenated culture medium for a short time interval to create ischemic damage. We will then investigate the differential roles of renal repair cells or stromal fibroblast in modulating tubular epithelial cell repair. By combining decellularized kidney scaffolds with human-derived renal cells within a biomimetic culture environment, we will investigate how human renal support cells dictate both kidney remodeling and epithelial cell differentiation during tissue regeneration. Understanding the processes of normal kidney regeneration and fibrogenesis leading to chronic kidney disease will allow us to develop more effective models, and ultimately improve therapies for treating renal disease.