title: Heat shock protein 70 is secreted from endothelial cells by a non-classical pathway involving exosomes.
abstract: Emerging evidence suggests that a high level of circulating heat shock protein 70 (HSP70) correlates with a lower risk of vascular disease; however, the biological significance of this inverse relationship has not been explored. Herein, we report that oxidative low density lipoprotein (Ox-LDL) and homocysteine (Hcy) induce HSP70 release from endothelial cells. In rat endothelial cells, Ox-LDL and Hcy induced robust release of HSP70, independent of the classical route of endoplasmic reticulum/Golgi protein trafficking or the formation of lipid rafts. In contrast, Ox-LDL and Hcy significantly enhanced the exosomal secretory rate and increased the HSP70 content of exosomes. Exogenous HSP70 had no impact on LPS-, Ox-LDL- and Hcy-induced activation of endothelial cells, whereas HSP70 did activate monocytes alone, resulting in monocyte adhesion to endothelial cells. These results indicate that exosome-dependent secretion of HSP70 from endothelial cells provides a novel paracrine mechanism to regulate vascular endothelial functional integrity.
authors: Department of Stress Medicine, Institute of Health & Environmental Medicine, Tianjin 300050, China.
authors: Rui
authors: R
authors: Zhan
authors: Xue
authors: X
authors: Leng
authors: Xiaohua
authors: X
authors: Liu
authors: Xinxing
authors: X
authors: Wang
authors: Jingbo
authors: J
authors: Gong
authors: Licheng
authors: L
authors: Yan
authors: Liqun
authors: L
authors: Wang
authors: Yang
authors: Y
authors: Wang
authors: Xiaoming
authors: X
authors: Wang
authors: Ling-Jia
authors: LJ
authors: Qian
mesh_terms: D000818:Animals; D054885:Cumulus Cells; D004730:Endothelium, Vascular / Q000378:metabolism* / Q000648:ultrastructure; D055354:Exosomes / Q000378:metabolism*; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism*; D021962:Membrane Microdomains / Q000378:metabolism; D051381:Rats
chemical_list: D018840:HSP70 Heat-Shock Proteins