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Osteopontin stimulates autophagy via integrin/CD44 and p38 MAPK signaling pathways in vascular smooth muscle cells

Authors

  • Yue-Hong Zheng,

    1. Department of Vascular Surgery, Peking Union Medical Hospital, Beijing, China
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  • Cui Tian,

    1. The Key Laboratory of Remodeling-Related Cardiovascular Diseases, Department of Pathology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
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  • Yan Meng,

    1. The Key Laboratory of Remodeling-Related Cardiovascular Diseases, Department of Pathology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
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  • Yan-Wen Qin,

    1. The Key Laboratory of Remodeling-Related Cardiovascular Diseases, Laboratory of Vascular Biology, Beijing Institute of Heart Lung and Blood Vessel Diseases, Beijing Anzhen Hospital Affiliated the Capital Medical University, Beijing, China
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  • Ya-Hao Du,

    1. The Key Laboratory of Remodeling-Related Cardiovascular Diseases, Department of Pathology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
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  • Jie Du,

    1. The Key Laboratory of Remodeling-Related Cardiovascular Diseases, Laboratory of Vascular Biology, Beijing Institute of Heart Lung and Blood Vessel Diseases, Beijing Anzhen Hospital Affiliated the Capital Medical University, Beijing, China
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  • Hui-Hua Li

    Corresponding author
    1. The Key Laboratory of Remodeling-Related Cardiovascular Diseases, Department of Pathology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
    • The Key Laboratory of Remodeling-Related Cardiovascular Diseases, Department of Pathology, School of Basic Medical Sciences, Capital Medical University, No. 10 Xitoutiao, You An Men, Beijing 100069, China.
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Abstract

Osteopontin (OPN) exerts pro-inflammatory effect and is associated with the development of abdominal aortic aneurysm (AAA). However, the molecular mechanism underlying this association remains obscure. In the present study, we compared gene expression profiles of AAA tissues using microarray assay, and found that OPN was the highest expressed gene (>125-fold). Furthermore, the expression of LC3 protein and autophagy-related genes including Atg4b, Beclin1/Atg6, Bnip3, and Vps34 was markedly upregulated in AAA tissues. To investigate the ability of OPN to stimulate autophagy as a potential mechanism involved in the pathogenesis of this disease, we treated vascular smooth muscle cells (SMCs) with OPN, and found that OPN significantly increased the formation of autophagosomes, expression of autophagy-related genes and cell death, whereas blocking the signal by anti-OPN antibody markedly inhibited OPN-induced autophagy and SMC death. Furthermore, inhibition of integrin/CD44 and p38 MAPK signaling pathways markedly abrogated the biological effects of OPN on SMCs. These data for the first time demonstrate that OPN sitmulates autophagy directly through integrin/CD44 and p38 MAPK-mediated pathways in SMCs. Thus, inhibition of OPN-induced autophagy might be a potential therapeutic target in the treatment of AAA disease. J. Cell. Physiol. 227: 127–135, 2012. © 2011 Wiley Periodicals, Inc.

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