ILK mediates the effects of strain on intestinal epithelial wound closure

Abstract

The intestinal epithelium is subjected to repetitive deformation during normal gut function by peristalsis and villous motility. Such repetitive strain promotes intestinal epithelial migration across fibronectin in vitro, but signaling mediators for this are poorly understood. We hypothesized that integrin-linked kinase (ILK) mediates strain-stimulated migration in intestinal epithelial cells cultured on fibronectin. ILK kinase activity increased rapidly 5 min after strain induction in both Caco-2 and intestinal epithelial cell-6 (IEC-6) cells. Wound closure in response to strain was reduced in ILK small interfering RNA (siRNA)-transfected Caco-2 cell monolayers when compared with control siRNA-transfected Caco-2 cells. Pharmacological blockade of phosphatidylinositol-3 kinase (PI3K) or Src or reducing Src by siRNA prevented strain activation of ILK. ILK coimmunoprecipitated with focal adhesion kinase (FAK), and this association was decreased by mutation of FAK Tyr925 but not FAK Tyr397. Strain induction of FAK Tyr925 phosphorylation but not FAK Tyr397 or FAK Tyr576 phosphorylation was blocked in ILK siRNA-transfected cells. ILK-Src association was stimulated by strain and was blocked by the Src inhibitor PP2. Finally, ILK reduction by siRNA inhibited strain-induced phosphorylation of myosin light chain and Akt. These results suggest a strain-dependent signaling pathway in which ILK association with FAK and Src mediates the subsequent downstream strain-induced motogenic response and suggest that ILK induction by repetitive deformation may contribute to recovery from mucosal injury and restoration of the mucosal barrier in patients with prolonged ileus. ILK may therefore be an important target for intervention to maintain the mucosa in such patients.

Mechanosensitivity of integrin adhesion complexes: role of the consensus adhesome

“…Furthermore, when high pressure is applied to carotid arteries, ILK expression is increased and the ILK-paxillin interaction is induced [83]. ILK is also required for cell migration in Caco-2 cells subjected to cyclic mechanical deformation in scratch assays [84], and its deficiency leads to decreased traction forces generated by VSMCs in response to stiffness on PDMS micropillars [85]. PINCH is stabilised in VSMCs subjected to stretch [86], whereas loss of function of PINCH in zebrafish led to ILK instability, cardiac failure and decreased expression of stretch-responsive genes [87].…”

ILK supports RhoA/ROCK-mediated contractility of human intestinal epithelial crypt cells by inducing the fibrillogenesis of endogenous soluble fibronectin during the spreading process

“…In the present study, considering the importance of FN for the intestinal crypt ECM/niche [27] and that ILK contribution to the regulation of intestinal epithelial cell functions (e.g. proliferation, restitution and wound healing) is related to FN deposition or adhesion [26,[28][29][30][31], we further investigated the functional linkage between ILK and FN for the regulation of integrin-actin axis dynamics in the context of HIEC cell spreading.…”

Electrical Stimulation and Recovery of Gastrointestinal Function Following Surgery: A Systematic Review

“…In one study, the abdominal vagus nerve was targeted for stimulation at the level of the diaphragmatic hiatus . The anti‐inflammatory effect of cervical VNS is described in other settings , and due to the interaction of the vagus nerve with the immune system, its ability to reduce inflammation is postulated to be beneficial in POI .…”