The Relationship Between SM22α And Vascular Cell Adhesion

Objective: Smooth muscle22alpha (SM22α) is an actin-binding protein.SM22α plays a key role in regulation of oxidative stress, inflammation andproliferation of VSMCs. However, the effect of SM22α on VSMC adhesionand migration remains to be identified. In this study, we illustrated therelationship of SM22α with vascular cell adhesion and migration following thecarotid artery injury of Sm22α-/-mice.Methods:Male SM22α-/-mice and their littermate wild-type (WT) controls (8to12-week-old) underwent a complete carotid artery ligation. The left commoncarotid artery was exposed and the right carotid artery served as a noninjuredcontrol artery. The ligation of artery was performed under anesthesia withisoflurane. The carotid arteries were harvested at0,1,3and7days after injury,and separated for preparation of sections. The cross-sectional areas of theintima and media were measured using Image Pro Plus6.0software. Theexpression of cell adhesion and migration-related proteins were analyzed byimmunohistochemistry.Results:1Expression of cell adhesion proteins is increased in Sm22α-/-mice aftercarotid injury.In Sm22α+/+mice, immunohistochemical staining showed that theexpression of ICAM-1and VCAM-1was rarely detected in the carotid arteriesof sham group. VCAM-1expression was increased at3days after ligation,with a peak at7days. The expression patterns of ICAM-1were similar toVCAM-1. Compared with Sm22α+/+mice, ICAM-1and VCAM-1expressionin the carotid media of SM22α-/-mice increased by1.56-and2.04-fold,respectively. 2Sm22α-/-mice show higher expression of migration-related proteins aftercarotid injury.In the injured carotids of Sm22α+/+mice, MMP-2and MMP-9expressionwas increased after1day of ligation, peaked at days3to7. Compared withSm22α+/+littermates, MMP-2and MMP-9expression was respectivelyincreased by4.83-and8.89-fold in carotid media of SM22α-/-mice.3The expression of OPN and integrin β3increased in injured carotids ofSm22α-/-mice.Immunohistochemistry results showed that the expression of OPN andintegrin β3in carotid arteries was not detected in sham group of Sm22α+/+mice,. OPN expression was increased after ligation for3days, and peaked at7days. Integrin β3expression peaked at3days. OPN expression was increasedby1.16times at7days and the expression of integrin β3was0.96timeshigher at3days in carotid media of SM22α-/-mice, compared with Sm22α+/+mice.Conclusions:1Compared with Sm22α+/+mice, the expression of adhesion-andmigration-related proteins are significantly increased in carotid media ofSM22α-/-mice after carotid injury.2Disruption of SM22α promotes VSMC adhesion and migration.