| Project/Area Number |
14570652
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Circulatory organs internal medicine
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| Research Institution | Hamamatsu University School of Medicine |
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Principal Investigator |
WATANABE Hirosi Hamamatsu University School of Medicine, Clinical Pharmacology and Ther apeutics, Professor, 医学部, 教授 (50262803)
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| Co-Investigator(Kenkyū-buntansha) |
KATOH Hideki Hamamatsu University School of Medicine, Internal Medicine III, Assistant Prof., 医学部, 助手 (80314029)
SATOH Hirosi Hamamatsu University School of Medicine, Internal Medicine III, Assistant Prof., 医学部附属病院, 助手 (30293632)
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| Project Period (FY) |
2002 – 2004
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| Project Status |
Completed (Fiscal Year 2004)
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| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2004: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2003: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 2002: ¥2,400,000 (Direct Cost: ¥2,400,000)
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| Keywords | apoptosis / endothelial cell / calcium / ER stress / caspase / Akt / PI3キナーゼ |
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| Research Abstract |
Apoptosis of endothelial cells (ECs) is now regarded to be an initial step inducing atherosclerosis. Recent studies have reported that the depletion of endoplasmic reticulum (ER) Ca^<2+> stores plays an important role in apoptosis. Caspase-12 is a key signal to lead ER stress-induced apoptosis. However, it is not known whether the depletion of ER Ca^<2+> is linked to caspase-12 signaling in ECs. Here we have investigated the interaction of Ca^<2+> signaling and caspase-12 cleavage in apoptosis of cultured porcine aortic ECs. Cytosolic Ca^<2+> concentration ([Ca^<2+>]i) was measured using fura-2/AM. Apoptosis was assessed by DNA ladder formation, and cleavage of caspase-12 by Western blotting. Thapsigargin (6μM), an inhibitor of the ER-associated Ca^<2+>-ATPase, increased [Ca^<2+>]i (F340/F380 ratio 0.717±0.137 to 6.133±0.710 : p<0.001) and induced persistent ER calcium depletion, cleavage of caspase-12 and apoptosis. Bradykinin (10 nM) increased [Ca^<2+>]i (F340/F380 ratio 0.717±0.053 to 6.133±0.528 : p<0.001) but induced neither cleavage of caspase-12 nor apoptosis. However, when ECs were treated with BAPTA/AM (100μM), BK caused the Ca^<2+> depletion of ER and apoptosis without the cleavage of caspase-12. Moreover non-selective caspase inhibitor, zVAD-fmk (100μM), inhibited apoptosis and cleavage of caspase-12 in TG-stimulated ECs, and calpain inhibitor, MDL 28170 (120μM), inhibited cleavage of caspase-12 but not inhibited apoptosis. These results suggested that the increase of [Ca^<2+>]i did not play an important role in inducing apoptosis in ECs, and ER Ca^<2+> depletion induced apoptosis, which is independent from caspase-12 linked signaling pathway.
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