Tubular obstruction by desquamated epithelial cells plays a critical role in the development of acute renal failure. A recent observation that viable renal tubular cells rather than cellular debris can be recovered from urine of patients with acute tubular necrosis, prompted an investigation into a possible defect in cell adhesion to the basement membrane. The hypothesis to be tested in the current research proposal is that loss of focal adhesions precipitates cell detachment from the basement membrane, while the concomitant reorientation of adhesion molecules, notably integrins, from their basal location to the apical cell surface results in adhesion of dislodged cells to the remaining epithelial layer and/or conglomeration of detached cells, both events culminating in tubular obstruction. The hypothesis will be tested by exploring three experimental aims: (1) To examine the mechanisms governing stress-induced cell detachment from the matrix, notably redistribution of integrin receptors and the role of protein kinases, cytosolic calcium, and the cytoskeleton in this process; (2) To study mechanisms of cell-cell adhesion of detached cells and attachment of dislodged cells to the epithelial layer; and (3) To evaluate the model of tubular obstruction in vivo and to examine the effect of maneuvers designed to reduce cell-cell adhesion and/or cell detachment on renal function after induction of acute ischemic or nephrotoxic injury. Cultured renal epithelial cells of primate origin (BSC-1) will constitute the in vitro model while whole animal models of acute renal failure will be used to corroborate the in vitro findings. The major techniques used in this study include intravital immunocytochemistry, interference reflection microscopy combined with microinjection of rhodamine phalloidin, digital ratio image analysis and confocal microscopy, FACS analysis, cell-matrix attachment assay, cell- cell attachment assay, molecular biological approaches for analysis of integrin mRNA. The results obtained in this research proposal will be integrated into a unifying hypothesis that will shed new light on the pathophysiologic mechanisms inducing tubular obstruction and acute renal compromise and outline potential methods of therapeutic intervention.
| Elitok, Saban; Brodsky, Sergey V; Patschan, Daniel et al. (2006) Cyclic arginine-glycine-aspartic acid peptide inhibits macrophage infiltration of the kidney and carotid artery lesions in apo-E-deficient mice. Am J Physiol Renal Physiol 290:F159-66 |
| Mezentsev, Alexandre; Merks, Roeland M H; O'Riordan, Edmond et al. (2005) Endothelial microparticles affect angiogenesis in vitro: role of oxidative stress. Am J Physiol Heart Circ Physiol 289:H1106-14 |
| Zhang, Xiaohui; Chen, Aileen; De Leon, Dina et al. (2004) Atomic force microscopy measurement of leukocyte-endothelial interaction. Am J Physiol Heart Circ Physiol 286:H359-67 |
| Brodsky, Sergey V; Zhang, Fan; Nasjletti, Alberto et al. (2004) Endothelium-derived microparticles impair endothelial function in vitro. Am J Physiol Heart Circ Physiol 286:H1910-5 |
| Chander, Praveen N; Gealekman, Olga; Brodsky, Sergey V et al. (2004) Nephropathy in Zucker diabetic fat rat is associated with oxidative and nitrosative stress: prevention by chronic therapy with a peroxynitrite scavenger ebselen. J Am Soc Nephrol 15:2391-403 |
| Hampel, Dierk J; Sansome, Christine; Romanov, Victor I et al. (2003) Osteopontin traffic in hypoxic renal epithelial cells. Nephron Exp Nephrol 94:e66-76 |
| Brodsky, Sergey V; Malinowski, Kazimierz; Golightly, Marc et al. (2002) Plasminogen activator inhibitor-1 promotes formation of endothelial microparticles with procoagulant potential. Circulation 106:2372-8 |
| Goligorsky, Michael S; Brodsky, Sergey V; Noiri, Eisei (2002) Nitric oxide in acute renal failure: NOS versus NOS. Kidney Int 61:855-61 |
| Kim, Byung-Soo; Chen, Jun; Weinstein, Talia et al. (2002) VEGF expression in hypoxia and hyperglycemia: reciprocal effect on branching angiogenesis in epithelial-endothelial co-cultures. J Am Soc Nephrol 13:2027-36 |
| Noiri, E; Nakao, A; Uchida, K et al. (2001) Oxidative and nitrosative stress in acute renal ischemia. Am J Physiol Renal Physiol 281:F948-57 |
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