Visceral Adipose Tissue-derived Serine Proteinase Inhibitor Inhibits Apoptosis of Endothelial Cells as a Ligand for the Cell-Surface GRP78/Voltage-dependent Anion Channel Complex

• Published in: Circulation research Vol. 112; no. 5; pp. 771 - 780
• Main Authors: Nakatsuka, Atsuko, Wada, Jun, Iseda, Izumi, Teshigawara, Sanae, Higashio, Kanji, Murakami, Kazutoshi, Kanzaki, Motoko, Inoue, Kentaro, Terami, Takahiro, Katayama, Akihiro, Hida, Kazuyuki, Eguchi, Jun, Ogawa, Daisuke, Matsuki, Yasushi, Hiramatsu, Ryuji, Yagita, Hideo, Kakuta, Shigeru, Iwakura, Yoichiro, Makino, Hirofumi
• Format: Journal Article
• Language: English
• Published: United States American Heart Association, Inc 01-03-2013
• Subjects: Adenoviridae - genetics; Adipokines - genetics; Adipokines - metabolism; Animals; Apoptosis - physiology; Cell Membrane - metabolism; Cell Proliferation; Cells, Cultured; Diabetes Mellitus, Experimental - chemically induced; Diabetes Mellitus, Experimental - metabolism; Diabetes Mellitus, Experimental - pathology; Disease Models, Animal; Endothelium, Vascular - pathology; Heat-Shock Proteins - metabolism; Humans; Ligands; Male; Mice; Mice, Inbred C57BL; Mice, Transgenic; Rats; Rats, Wistar; Serpins - genetics; Serpins - metabolism; Streptozocin - adverse effects; Voltage-Dependent Anion Channels - metabolism
• ISSN: 0009-7330; 1524-4571
• DOI: 10.1161/CIRCRESAHA.111.300049

RATIONALE:Visceral adipose tissue-derived serine proteinase inhibitor (vaspin) is an adipokine identified from visceral adipose tissues of genetically obese rats.
OBJECTIVE:The role of vaspin in the diabetic vascular complications remains elusive, and we investigated the effects of vaspin on the vascular function under the diabetic milieu.
METHODS AND RESULTS:Adenovirus carrying the full length of the vaspin gene (Vaspin-Ad) ameliorated intimal proliferation of balloon-injured carotid arteries in diabetic Wistar rats. The expression of Ccl2, Pdgfb, and Pdgfrb genes was significantly reduced by the treatment of Vaspin-Ad. In cuff-injured femoral arteries, the intimal proliferation was ameliorated in vaspin transgenic (Vaspin Tg) mice. The application of recombinant vaspin and Vaspin-Ad promoted the proliferation and inhibited the apoptosis of human aortic endothelial cells. Adenovirus expressing vaspin with calmodulin and streptavidin-binding peptides was applied to human aortic endothelial cells, subjected to tandem tag purification and liquid chromatography-tandem mass spectrometry, and we identified GRP78 (78-kDa glucose-regulated protein) as an interacting molecule. The complex formation of vaspin, GRP78, and voltage-dependent anion channel on the plasma membrane was confirmed by the immunoprecipitation studies using aortas of Vaspin Tg mice. The binding assay using I-vaspin in human aortic endothelial cells revealed high-affinity binding (dissociation constant = 0.565×10 m) by the treatment of 5 μM thapsigargin, which recruited GRP78 from the endoplasmic reticulum to plasma membrane by inducing endoplasmic reticulum stress. In human aortic endothelial cells, vaspin induced phosphorylation of Akt and inhibited the kringle 5-induced Ca influx and subsequent apoptosis.
CONCLUSIONS:Vaspin is a novel ligand for the cell-surface GRP78/voltage-dependent anion channel complex in endothelial cells and promotes proliferation, inhibits apoptosis, and protects vascular injuries in diabetes mellitus.