| Project/Area Number |
11671052
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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 |
Kidney internal medicine
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| Research Institution | Showa University |
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Principal Investigator |
MORITA Hiroyuki Showa University, School of Medicine, Associate professor, 医学部, 講師 (00311994)
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| Co-Investigator(Kenkyū-buntansha) |
KIMATA Koji Aich Medical University, Institute for Molecular Science of Medicine, Professor, 分子医科学研究所, 教授 (10022641)
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| Project Period (FY) |
1999 – 2000
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,400,000 (Direct Cost: ¥3,400,000)
Fiscal Year 2000: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1999: ¥2,300,000 (Direct Cost: ¥2,300,000)
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| Keywords | charge barrier / heparan sulfate proteoglycans / perlecan / gene targeting / homozygous mouse / GBM / negative charge theory / proteinuria / 糸球体ろ過 / チャ-ジバリア / パーリカン / 遺伝子ターゲティング |
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| Research Abstract |
In the process of glomerular filtration, glomerular basement membranes (GBM) serve as a charge barrier to retain negatively-charged macromolecules in the circulation. On the molecular basis, GBM heparan sulfate prteoglycans (HSPG) have been thought of as key components that constitute the barrier. This negative charge theory has long been generally accepted. However, there is no direct evidence at the molecular level which links the collapse of the barrier to the development of proteinuria. Perlecan is a major GBM HSPG. Perlecan encompasses five molecular domains. Exon 3 of the first domain encodes heparan sulfate attachment sites. The present study was designed to evaluate negative charge theory from a different perspective. By the use of embryonic stem (ES) cell technology, the exon 3 was removed without frame shift. As a result, homozygous mouse was produced having mutated perlecan molecule. Our biochemical analysis at the post-transcriptional level demonstrated fibroblast obtained from the homozygote produed perlecan without heparan sulfates having an intact size of the core molecule. Although homozygotes did not spontaneously show massive proteinuria, intra-peritoneal albumin overload resulted in significant increase in urinary protein excretion after 2 weeks. Our immunoelectron microscopic investigation disclosed PEI stained sites in the GBM of homozygotes was not different from those of wild-type controls. The results strongly indicated other GBM HSPG compensate the loss of perlecan heparan sulfate. Agrin, another GBM HSPS, was not a candidate.
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