PDGF-induced migration of synthetic vascular smooth muscle cells through c-Src-activated L-type Ca2+ channels with full-length CaV1.2 C-terminus.

Abstract

In atherosclerosis, vascular smooth muscle cells (VSMC) migrate from the media toward the intima of the arteries in response to cytokines, such as platelet-derived growth factor (PDGF). However, molecular mechanism underlying the PDGF-induced migration of VSMCs remains unclear. The migration of rat aorta-derived synthetic VSMCs, A7r5, in response to PDGF was potently inhibited by a CaV1.2 channel inhibitor, nifedipine, and a Src family tyrosine kinase (SFK)/Abl inhibitor, bosutinib, in a less-than-additive manner. PDGF significantly increased CaV1.2 channel currents without altering CaV1.2 protein expression levels in A7r5 cells. This reaction was inhibited by C-terminal Src kinase, a selective inhibitor of SFKs. In contractile VSMCs, the C-terminus of CaV1.2 is proteolytically cleaved into proximal and distal C-termini (PCT and DCT, respectively). Clipped DCT is noncovalently reassociated with PCT to autoinhibit the channel activity. Conversely, in synthetic A7r5 cells, full-length CaV1.2 (CaV1.2FL) is expressed much more abundantly than truncated CaV1.2. In a heterologous expression system, c-Src activated CaV1.2 channels composed of CaV1.2FL but not truncated CaV1.2 (CaV1.2Δ1763) or CaV1.2Δ1763 plus clipped DCT. Further, c-Src enhanced the coupling efficiency between the voltage-sensing domain and activation gate of CaV1.2FL channels by phosphorylating Tyr1709 and Tyr1758 in PCT. Compared with CaV1.2Δ1763, c-Src could more efficiently bind to and phosphorylate CaV1.2FL irrespective of the presence or absence of clipped DCT. Therefore, in atherosclerotic lesions, phenotypic switching of VSMCs may facilitate pro-migratory effects of PDGF on VSMCs by suppressing posttranslational CaV1.2 modifications.

• Authors: Xiaoguang Guo, Toshihide Kashihara, Tsutomu Nakada, Toshifumi Aoyama, Mitsuhiko Yamada
• Journal: Pflugers Archiv : European journal of physiology (Pflugers Arch) Vol. 470 Issue 6 Pg. 909-921 (06 2018) ISSN: 1432-2013 [Electronic] Germany
• PMID: 29441404 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Calcium Channels, L-Type
• Platelet-Derived Growth Factor
• src-Family Kinases

Topics

• Animals
• Atherosclerosis (metabolism, pathology, physiopathology)
• Calcium Channels, L-Type (chemistry, metabolism)
• Cells, Cultured
• HEK293 Cells
• Humans
• Male
• Muscle, Smooth, Vascular (metabolism, pathology, physiopathology)
• Myocytes, Smooth Muscle (drug effects, metabolism, pathology)
• Platelet-Derived Growth Factor (pharmacology)
• Protein Domains
• Rats
• Rats, Sprague-Dawley
• Transendothelial and Transepithelial Migration
• src-Family Kinases (metabolism)