Integrin and FAK-mediated MAPK activation is required for cyclic strain mitogenic effects in Caco-2 cells

Abstract

Rhythmic strain stimulates Caco-2 proliferation. We asked whether mitogen-activated protein kinase (MAPK) activation mediates strain mitogenicity and characterized upstream signals regulating MAPK. Caco-2 cells were subjected to strain on collagen I-precoated membranes or antibodies to integrin subunits. Twenty-four hours of cyclic strain increased cell numbers compared with static conditions. MAPK-extracellular signal-regulated kinase (ERK) kinase inhibition (20 microM PD-98059) blocked strain mitogenicity. p38 Inhibition (10 microM SB-202190) did not. Strain rapidly and time-dependently activated focal adhesion kinase (FAK), paxillin, ERK1 and 2, and p38 on collagen. c-Jun NH(2)-terminal kinase (JNK)1 and 2 exhibited delayed activation. Similar activation occurred when Caco-2 cells were subjected to strain on a substrate of functional antibody to the alpha2-, alpha3-, alpha6-, or beta1-integrin subunits but not on a substrate of functional antibody to the alpha5-subunit. FAK inhibition by FAK397 transfection blocked ERK2 and JNK1 activation by in vitro kinase assays, but pharmacological protein kinase C inhibition did not block ERK1 or 2 activation by strain. Strain-induced ERK signals mediate strain's mitogenic effects and may require integrins and FAK activation.

Changes in Morphology and Function in Small Intestinal Mucosa After Roux-en-Y Surgery in a Rat Model

“…Repetitive deformation also stimulates proliferation and regulates enterocytic differentiation via a complex signal pathway (10) that involves tyrosine kinase and PKC activation and downstream ERK-mediated signaling (12). These observations are consistent with our present observation that ERK signaling is decreased in the atrophic defunctionalized mucosa in vivo.…”

“…In vitro, repetitive deformation stimulates the proliferation of intestinal epithelial cells on collagen substrates, modulates differentiation marker expression, and activates p38 and JNK signaling in intestinal Caco-2 cells in response to repetitive deformation (12). In vivo, repetitive deformation alone stimulates intracellular signaling within small intestinal or colonic mucosa in anesthetized rats (13).…”

Cyclic AMP Activation of the Extracellular Signal-regulated Kinases 1 and 2

“…Only confluent or near confluent T84 cells can activate ERK1/2 via cAMP, implying that the formation of cell-cell contacts is important. ERK1/2 signaling has been previously linked to cell adhesion in fibroblasts (42) and in a model of cyclic strain in the intestinal Caco-2 cell line through focal adhesion kinase (Fak) (43). Cyclic AMP signaling through Fak or a similar integrin-associated pathway was not evaluated in this study.…”

CYP24 Promoter Activity is Affected by Mechanical Stress and Mitogen-Activated Protein Kinase in MG63 Osteoblast-like Cells

“…Mechanical stress was applied following published techniques in which MAPK signal transduction was induced by mechanical stress. 10,11 Cells were stretched with a 10% biaxial strain at a frequency of 30 times/min for 14 hours with a cell strain unit (FX-3000, Flexcell International, Hillsborough, NC, USA).…”