Rotavirus Replication in Intestinal Cells Differentially Regulates Integrin Expression by a Phosphatidylinositol 3-Kinase-Dependent Pathway, Resulting in Increased Cell Adhesion and Virus Yield

Abstract

Changes in the interactions between intestinal cells and their surrounding environment during virus infection have not been well documented. The growth and survival of intestinal epithelial cells, the main targets of rotavirus infection, are largely dependent on the interaction of cell surface integrins with the extracellular matrix. In this study, we detected alterations in cellular integrin expression following rotavirus infection, identified the signaling components required, and analyzed the subsequent effects on cell binding to the matrix component collagen. After rotavirus infection of intestinal cells, expression of ␣2␤1 and ␤2 integrins was up-regulated, whereas that of ␣V␤3, ␣V␤5, and ␣5␤1 integrins, if present, was down-regulated. This differential regulation of integrins was reflected at the transcriptional level. It was unrelated to the use of integrins as rotavirus receptors, as both integrin-using and integrin-independent viruses induced integrin regulation. Using pharmacological agents that inhibit kinase activity, integrin regulation was shown to be dependent on phosphatidylinositol 3-kinase (PI3K) but independent of the activities of the mitogen-activated protein kinases p38 and ERK1/2, and cyclooxygenase-2. Replication-dependent activation of the PI3K/Akt pathway was observed following infection of intestinal and nonintestinal cell lines. Rotavirus activation of PI3K was important for regulation of ␣2␤1 expression. Blockade of integrin regulation by PI3K inhibition led to decreased adherence of infected intestinal cells to collagen and a concomitant decrease in virus titer. These findings indicate that rotavirus-induced PI3K activation causes regulation of integrin expression in intestinal cells, leading to prolonged adherence of infected cells to collagen and increased virus production.Rotavirus is a major cause of dehydrating gastroenteritis in infant humans and animals throughout the world. Differentiated epithelial cells on villi in the small intestine (enterocytes) are the main targets of infection, leading to cell death, a reduction in villus epithelium area, loss of absorptive capacity, and osmotic dysregulation (3,7,48,53). Enterocytes are attached to the basement membrane through interactions between the basement matrix and cell-surface adhesion molecules, mainly members of the integrin family (4,6,49,64). Increased enterocyte loss is a feature of rotavirus disease, suggesting that reduced enterocyte adhesion occurs (9). However, the molecules involved in changes in attachment of enterocytes to the matrix during rotavirus infection and how this process relates to viral replication and pathogenesis have not been analyzed.Integrins provide a means for cells to respond to their environment through intracellular signaling networks controlling crucial cellular processes such as adhesion, proliferation, migration, differentiation, and survival (1,20,38,55,69). These ␣␤ heterodimeric glycoproteins have been identified as cellular receptors or entry cofactors for many viruses, including rotavi...

Rotavirus acceleration of murine type 1 diabetes is associated with a T helper 1-dependent specific serum antibody response and virus effects in regional lymph nodes

“…as previously described [23]. Psoralen/UV inactivation of RRV was performed and verified as before [24,25].…”

Rotavirus Infection Accelerates Type 1 Diabetes in Mice with Established Insulitis

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Rotavirus Nonstructural Protein 1 Suppresses Virus-Induced Cellular Apoptosis To Facilitate Viral Growth by Activating the Cell Survival Pathways during Early Stages of Infection

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