Knockdown of P120 catenin aggravates endothelial injury under an impinging flow by inducing breakdown of adherens junctions.

Abstract

At present, the mechanisms underlying intracranial aneurysm(IA) development remain unclear; however, hemodynamics is considered a crucial factor in the induction of IA. To elucidate the association between hemodynamics and endothelial cell (EC) functions, a modified Tchamber system was designed to simulate the adjustable hemodynamic conditions of an artery bifurcation. Normal human umbilical vein ECs (HUVECs) and HUVECs with P120 catenin (P120ctn) knockdown were cultured on coverslips and placed in the chamber. A flow rate of 250 or 500ml/min impinged on the cell layer. Subsequently, the expression levels of P120ctn and other proteins, and EC morphological alterations, were examined. In normal HUVECs, after 3h under a flow rate of 500ml/min, the expression levels of P120ctn, vascular endothelial (VE)‑Cadherin, Kaiso and α‑catenin were decreased, whereas matrix metalloproteinase‑2 (MMP‑2) was increased. In HUVECs with P120ctn knockdown, the period during which ECs adhered to the coverslip was reduced to 1h under a flow rate of 500ml/min. In addition, the expression levels of VE‑Cadherin, Kaiso and α‑catenin in ECs were decreased, whereas those of MMP‑2 were increased after 1h; more prominent alterations were detected under a 500ml/min flow rate compared with a 250ml/min flow rate. Adherens junctions (AJs) are critical to the maintenance of normal morphology and EC functioning in the vascular wall, and P120ctn is an important regulator of AJs. Loss of P120ctn may be induced by hemodynamic alterations. In response to changes in hemodynamic conditions, a loss of P120ctn may aggravate AJs between ECs, thus inducing inflammation in the vascular wall. Clinically, hemodynamic alterations may result in a loss of P120ctn and endothelial injury; therefore, P120ctn may have a critical role in inducing intracranial aneurysms.