Redistribution and dysfunction of integrins in cultured renal epithelial cells exposed to oxidative stress

Abstract

Tubular obstruction by detached renal tubular epithelial cells is a major cause of oliguria in acute renal failure. Viable renal tubular cells can be recovered from urine of patients with acute tubular necrosis, suggesting a possible defect in cell adhesion to the basement membrane. To study this process of epithelial cell desquamation in vitro, we investigated the effect of nonlethal oxidative stress on the integrin adhesion receptors of the primate kidney epithelial cell line BS-C-1. Morphological and functional studies of cell adhesion properties included the following: interference reflection microscopy, intravital confocal microscopy and immunocytochemistry, flow cytometric analysis of integrin receptor abundance, and cell-matrix attachment assay. High levels of the integrin subunits alpha 3, alpha v, and beta 1 were detected on the cell surface by fluorescence-activated cell sorting (FACS) analysis, as well as lower levels of alpha 1, alpha 2, alpha 4, alpha 5, alpha 6, and beta 3. Exposure of BS-C-1 cells to nonlethal oxidative stress resulted in the disruption of focal contacts, disappearance of talin from the basal cell surface, and in the redistribution of integrin alpha 3-subunits from predominantly basal location to the apical cell surface. As measured in a quantitative cell attachment assay, oxidative stress decreased BS-C-1 cell adhesion to type IV collagen, laminin, fibronectin, and vitronectin. Defective adhesion was not associated with a loss of alpha 3-, alpha 4-, or alpha v-integrin subunits from the cell surface.(ABSTRACT TRUNCATED AT 250 WORDS)

Heat Shock Protein 27 Is the Major Differentially Phosphorylated Protein Involved in Renal Epithelial Cellular Stress Response and Controls Focal Adhesion Organization and Apoptosis

“…Nephrotoxic cysteine conjugates, including DCVC, affect the adhesion of renal epithelial cells to the extracellular matrix (20). This is associated with reorganization of the F-actin cytoskeletal network, loss of focal adhesions, and dephosphorylation of several components that are associated with focal adhesions (20,26). Treatment of LLC-PK1 cells with DCVC alone caused a slight increase in loss of cell adhesion after 8 h (Fig.…”

“…DCVC is specifically taken up by renal proximal tubular cells both in vitro and in vivo where it is bio-activated by the renal cysteine conjugate ␤-lyase activity, resulting in the formation of reactive intermediates that cause cell injury (23,25). PTC injury is associated with loss of focal adhesions and cell adhesion, which is followed by caspase activation and the onset of apoptosis (20,26,27). Focal adhesion-mediated signaling seems to be an important component in the control of DCVC-induced apoptosis, because DCVC causes the loss of FAK phosphorylation and thereby activity and promotes the loss of focal adhesion organization (28).…”

Renal Ischemia/Reperfusion Injury

“…Recently, attention has focused on the role of ␤1 integrins in the loss of tubular cells and tubular lumen occlusion by cellular debris during acute IRI (2). Using an in vitro model of renal epithelial cells that were exposed to oxidative stress, it was demonstrated redistribution of the ␣3␤1 integrin-subunit from the basolateral to apical cell membranes (16). Also, in an in vivo model of IRI, it has been proposed that the decrease of ␤1 integrins on basal surfaces contributes to tubular epithelia detachment into the lumen.…”

Pathogenetic role of Arg-Gly-Asp-recognizing integrins in acute renal failure. off.

“…Indeed, oxidant stress to renal epithelia resulted in redistribution of several subunits of integrin receptors from the predominantly basal location to the apical cell membrane (8). This phenomenon has underscored both the detachment of cells from the matrix and their potential cytoattractant properties (8,9). The present study was undertaken to examine cytoattractive properties of stressed epithelial cells in vitro and in vivo, as well as the involvement of integrin receptors in this process.…”

“…on cytoattraction and on the dynamics of proximal tubular pressure was examined. layers and with monolayers pretreated with 1 mM H202 for 10 min, which results in apical expression of integrin receptors (8).…”