P21WAF1 Is Required for Interleukin-16-Induced Migration and Invasion of Vascular Smooth Muscle Cells via the p38MAPK/Sp-1/MMP-9 Pathway.

Sung Lyea Park,Won Tae Kim,Byungdoo Hwang,Sun-Young Lee,Wun-Jae Kim,Yung Hyun Choi,Sung-Kwon Moon,Young-Chae Chang,Francis Miller

doi:10.1371/journal.pone.0142153

Abstract

Interleukin-16 (IL-16) is a lymphocyte chemoattractant factor well known for its role in immune responses, but its role in vascular disease is unknown. Here, we explored the novel physiological function of IL-16 in vascular smooth muscle cells (VSMCs). The expression of IL-16 and its receptor CD4 was observed in VSMCs. Treatment with IL-16 enhanced the migration and invasion by VSMCs without altering the proliferative potential. IL-16 induced MMP-9 expression via the binding activity of transcription factors NF-κB, AP-1, and Sp-1 motifs in VSMCs. Among the relevant signaling pathways examined, only p38MAPK phosphorylation was significantly stimulated in IL-16-treated VSMCs. Treatment with p38MAPK inhibitor SB203580 prevented the IL-16-induced migration and invasion of VSMCs. SB203580 treatment inhibited the MMP-9 expression and activation of Sp-1 binding in IL-16-treated VSMCs, and siRNA knockdown of CD4 expression blocked the induction of migration, invasion, p38MAPK phosphorylation, MMP-9 expression, and Sp-1 binding activation stimulated by IL-16. The IL-16 induced cell-cycle-inhibitor p21WAF1 expression in VSMCs, but had no effect on the expression levels of other cell-cycle negative regulators. Finally, blockage of p21WAF1 function with specific siRNA abolished the IL-16-induced elevation of migration, invasion, p38MAPK phosphorylation, MMP-9 expression, and Sp-1 binding activation in VSMCs. Taken together, p21WAF1 was required for the induction of p38MAPK-mediated MMP-9 expression via activation of the Sp-1 binding motif, which led to migration and invasion of VSMCs interacting with IL-16/CD4. These results could provide that IL-16 is a new target in the treatment of vascular diseases such as atherosclerosis and re-stenosis.

Highlights

Vascular disease is one of the most common causes of death in developed countries [1]
Because Matrix metalloproteinases (MMPs)-9 expression is regulated by three types of transcription factors, NF-κB, Sp-1, and AP-1 [5, 6, 8], we investigated whether IL-16 could stimulate the transcriptional activation of these factors in vascular smooth muscle cells (VSMCs)
The main finding of the present study establishes IL-16 as a key regulator of migration and invasion by VSMCs via binding with CD4, which results in the induction of p38MAPK phosphorylation, MMP-9 expression, and Sp-1 binding activation

Summary

Introduction

Vascular disease is one of the most common causes of death in developed countries [1]. The migration and invasion by vascular smooth muscle cells (VSMCs) is a main cause of the vascular lesion formations that lead to vascular diseases including atherosclerosis and re-stenosis [1]. Matrix metalloproteinases (MMPs) play an essential role in the degradation of the extracellular matrix (ECM) components of VSMCs during plaque instability after vascular injury responses [2]. Both in vitro and in vivo experiments have demonstrated how the gelatinase MMP-9 (92 kDa) degradation enzyme of type IV collagen is a pivotal factor in the promotion of the vascular lesion process [2,3,4,5]. The transcription factors NF-κB, Sp-1, and AP-1 are the main transcriptional cis-elements that induce the expression of MMP-9 [5, 6, 8]

Methods

Results

Conclusion