| Project/Area Number |
14570771
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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 |
Pediatrics
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| Research Institution | Kyorin University |
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Principal Investigator |
YAN Kunimasa Kyorin University, Department of Pediatrics, Associate Professor, 医学部, 助教授 (70255389)
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| Co-Investigator(Kenkyū-buntansha) |
HOSOYAMADA Makoto Kyorin University, Dept. of Pharmacology and Toxicology, Assistant Professor, 医学部, 講師 (00291659)
KUDO Akihiko Kyorin University, Dept. of Anatomy, Assistant Professor, 医学部, 講師 (80255398)
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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 |
¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 2004: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2003: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2002: ¥1,800,000 (Direct Cost: ¥1,800,000)
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| Keywords | podocin / nephrin / slit membrane / protein transport / missense mutant / 蛋白細胞内輸送 / ネフローゼ / Podocin / Nephrin / 細胞内蛋白輸送 |
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| Research Abstract |
Steroid resistant congenital nephrotic syndrome (SRN) is one of the hereditary kidney diseases, which presents heavy proteinuria 3 months after its birth.
The aim of the present study was to determine the protein function of podocin by the analysis with podocin mutagenesis study and the possible implication in the proteinuric state in the acquired nephrotic syndrome.
Our specific anti-podocin antibody developed by the present project clearly determined the co-localization of podocin and nephrin, which is the major molecule serving permselectivity barrier in the glomerulus, in the podocyte slit diaphragm. Co-immunoprecipitation using this antibody and the protein sample from isolated glomeruli showed that podocin is real intracellular ligand of nephrin in human podocyte foot processes. In order to clarify the mechanism of the proteinuria in SRN, the mutagenesis study was done by using the expression experiment with missense mutants demonstrating SRN patient. The C-terminal missense podocin mutants were demonstrated not to be transported to the plasma membrane possibly because of its aggregation in the endoplasmic reticulum or lysozome. Moreover these podocin mutants also inhibited the correct plasma membrane assembly of its ligand, nephrin, because of their strong protein affinity. Puromycin-Aminonucleoside rat nephrosis, which is a modlel demonstrating minimal change nephrotic sydrome, was developed to determine the implication of podocin in the pathomechanism of the proteinuria. Interestingly, the protein expression of podocin as well as nephrin was clearly decreased before the onset of the proteinuria. This result suggested the pivotal role of podocin together with nephrin in the pathomechanism in the proteinuria not only its mutated nephrosis also in the acquired nephrotic syndrome.
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