| Project/Area Number |
14370319
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Kidney internal medicine
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| Research Institution | OKAYAMA UNIVERSITY |
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Principal Investigator |
MAKINO Hirofumi Okayama University, Graduate School of Medicine, Dentistry and pharmaceutical Sciences, Professor, 大学院・医歯薬学総合研究科, 教授 (50165685)
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| Co-Investigator(Kenkyū-buntansha) |
WADA Jun Okayama University, University Hospital, Assistant Professor, 医学部・歯学部附属病院, 講師 (30294408)
SHIKATA Kenichi Okayama University, University Hospital, Assistant Professor, 医学部・歯学部附属病院, 講師 (00243452)
NAKAMURA Yoshio Okayama University, University Hospital, Assistant Professor, 医学部・歯学部附属病院, 講師 (30314686)
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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 |
¥9,100,000 (Direct Cost: ¥9,100,000)
Fiscal Year 2004: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2003: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2002: ¥6,500,000 (Direct Cost: ¥6,500,000)
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| Keywords | Diabetic nephropathy / ROS / Mitochondria / Gene therapy / Tim44 / UCP-1 / Mn-SOD |
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| Research Abstract |
Hyperglycemia-induced overproduction of mitochondrial reactive oxygen species (ROS) has emerged as a major player in diabetic vascular complications. Mammalian translocase of inner mitochondrial membrane 44 (Tim44) was identified by up-regulation in diabetic mouse kidneys. Tim44 functions as a membrane anchor of mtHsp70 to TIM23 complex and involves in the import of mitochondria-targeted preproteins into mitochondrial matrix. The process is dependent on inner membrane potential (Δψ) and ATP hydrolysis on ATPase domain of mtHsp70. Hemagglutination virus of Japan (HVJ)-envelope vector carrying pcDNA3.1 plasmid containing the full length cDNA of Tim44 and control plasmid were weekly injected from tail vein into uninephrectomized streptozotocin-induced diabetic CD-1 mice. The gene delivery alleviated proteinuria and renal hypertrophy at 8 weeks after the injection and inhibited renal cell proliferation and apoptosis, and suppressed superoxide production. In vitro experiments, using human proximal tubular (HK2) cells, revealed that the gene delivery of Tim44 reversed high glucose induced metabolic and cellular abnormalities such as, enhanced ROS production, increased ATP contents, alterations in inner membrane potential, increased cell proliferation and apoptosis. Transfection with siRNA and expressing vector of Tim44 revealed that Tim44 facilitates import of anti-oxidative enzymes such as superoxide dismutase (SOD) and glutathione peroxidase into mitochondria. The gene delivery of Tim44 thus seems to be beneficial for the maintenance of mitochondrial function and is a novel therapeutic approach for diabetic nephropathy.
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