Chlamydophila (Chlamydia) pneumoniae infection promotes vascular smooth muscle cell adhesion and migration through IQ domain GTPase-activating protein 1

The mechanisms for Chlamydophila (Chlamydia) pneumoniae (C. pneumoniae) infection-induced atherosclerosis are still unclear. Cell adhesion has important roles in vascular smooth muscle cell (VSMC) migration required in the development of atherosclerosis. However, it is still unknown whether IQ domain GTPase-activating protein 1 (IQGAP1) plays pivotal roles in C. pneumoniae infection-induced the adhesion and migration of rat primary VSMCs. Accordingly, in this study, we demonstrated that rat primary VSMC adhesion (P < 0.001) and migration (P < 0.01) measured by cell adhesion assay and Transwell assay, respectively, were significantly enhanced after C. pneumoniae infection. Reverse transcription-polymerase chain reaction analysis revealed that the mRNA expression levels of IQGAP1 in the infected rat primary VSMCs were found to increase gradually to reach a peak and then decrease gradually to a level similar to the control. We further showed that the increases in rat primary VSMC adhesion to Matrigel (P < 0.001) and migration (P < 0.01) caused by C. pneumoniae infection were markedly inhibited after IQGAP1 knockdown by a pool of four short hairpin RNAs. Taken together, our results suggest that C. pneumoniae infection may promote the adhesion and migration of VSMCs possibly by upregulating the IQGAP1 expression.

► C. pneumoniae infection increases the adhesion of vascular smooth muscle cells. ► C. pneumoniae infection promotes the migration of vascular smooth muscle cells. ► IQGAP1 expression was increased in the infected vascular smooth muscle cells. ► Depletion of IQGAP1 inhibits the infection-induced cell adhesion and migration.