Mechanical stress‐activated PKCδ regulates smooth muscle cell migration

Abstract

Vascular smooth muscle cells (SMCs) are exposed to altered mechanical stress that may contribute to SMC migration in the development of atherosclerosis. Signal transduction pathways in SMCs activated by mechanical stress that instigate cell migration are undefined. Herein, we provide evidence that mechanical stress enhances SMC migration, which is mediated, at least in part, by protein kinase C (PKC)delta. When rat SMCs cultivated on a flexible membrane were subjected to cyclic strain stress (60 cycles/min, 5, 15, or 20% elongation), PKCdelta was translocated to the Triton-insoluble fraction, whereas PKCalpha was translocated to the membrane, which was confirmed by PKC kinase assays. Immunofluorescence and actin staining revealed a cytoskeleton translocation of PKCdelta in SMCs stimulated by cyclic strain. PKCdelta-deficient SMCs cultivated from PKCdelta-/- mice showed an abnormal cytoskeleton structure, which was related to a diminished phosphorylation of paxillin, focal adhesion kinase, and vinculin in response to mechanical stress. Mechanical stress enhanced SMC migration, which was diminished in PKCdelta-/- SMCs. Taken together, our data demonstrated that mechanical stress activates PKCdelta translocation to the cytoskeleton, which is related to decreased SMC migration and indicates that PKCdelta is a key signal transducer between mechanical stress and cell migration.

Signal-Crosstalk Between Rho/ROCK and c-Jun NH 2 -Terminal Kinase Mediates Migration of Vascular Smooth Muscle Cells Stimulated by Angiotensin II

“…33,34 Moreover, mechanical stress-induced VSMC migration was diminished in VSMCs derived from PKC␦ null mice. 35 Overexpression of a PYK2 inhibitory protein blocked monocyte motility, 36 and macrophage from PYK2 null mice showed impaired migration. 37 Therefore, the present findings nicely connect these essential kinases and delineate a previously unidentified signal transduction relay of VSMC migration in which Rho/ROCK represent essential intermediates.…”

Proteomic and Metabolomic Analysis of Vascular Smooth Muscle Cells

“…Most of our knowledge about the role of PKC␦ is derived from studies using rottlerin, a putative PKC␦ inhibitor. 13,32,33 Data presented are given in mol/g protein (meanϮSE, nϭ4 biological replicates in each group, except for PKC␦ ϩ/Ϫ SMCs nϭ3, measurements were performed in duplicates, total nϭ22).…”

“…11 Besides modulating apoptosis, PKC␦ was found to be important for cytoskeleton rearrangement and cell migration. 13 However, the molecular mechanisms of resistance to apoptosis and cytoskeletal abnormalities in PKC␦ Ϫ/Ϫ SMCs are unknown. In the present study, we performed a thorough analysis of the proteome and metabolome of vascular SMCs derived from PKC␦ ϩ/ϩ and PKC␦ Ϫ/Ϫ mice.…”

“…Most of our knowledge about the role of PKC␦ is derived from studies using rottlerin, a putative PKC␦ inhibitor. 13,32,33 Data presented are given in mol/g protein (meanϮSE, nϭ4 biological replicates in each group, except for PKC␦ ϩ/Ϫ SMCs nϭ3, measurements were performed in duplicates, total nϭ22).P values for differences between the 3 groups were derived from ANOVA tables (bold numbers highlight significant differences from wild-type controls in the Fisher PLSD test), P values for the linear trend are listed in the far right column. …”

Cyclic tensile strain triggers a sequence of autocrine and paracrine signaling to regulate angiogenic sprouting in human vascular cells

“…Mechanical signals regulate the function of both cell types in vitro, including the alteration of EC proliferation (7,8), alignment (9, 10), migration (11,12), and in vitro sprout formations (13,14), likely through activating various intracellular signaling pathways (15)(16)(17)(18)(19)(20)(21). Similarly, physiologically relevant hemodynamic forces have demonstrated to modulate SM phenotype (22), migration (23), and intracellular signaling (24). Altogether, these past studies suggest that the angiogenic process is governed by an interplay between chemical and mechanical signals.…”