1995 Fiscal Year Final Research Report Summary
Molecular Biology of B-Cells of Pancreatic Islets of Langerhans : Basic Study to develop Gene Therapy for Diabetes
| Project/Area Number |
06304034
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| Research Category |
Grant-in-Aid for Co-operative Research (A)
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| Allocation Type | Single-year Grants |
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| Research Field |
内分泌・代謝学
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| Research Institution | The University of Tokushima |
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Principal Investigator |
ITAKURA Mituo Sch.Med. Univ Tokushima, Prof., 医学部, 教授 (60134227)
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| Co-Investigator(Kenkyū-buntansha) |
KIKUTANI Hitoshi Inst.Mol.Cell.Biol., Osaka Univ, Ass.Prof., 細胞生体工学センター, 助教授 (80161412)
KOJIMA Itaru Biol.Regul.Res.Inst, Gunma Univ, Prof., 生体調節研究所, 教授 (60143492)
MIYAZALO Junichi Inst.Dev.Aging Cancer, Tohoku Univ., Prof., 加齢医学研究所・遺伝子導入分野, 教授 (10200156)
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| Project Period (FY) |
1994 – 1995
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| Keywords | gene therapy / B-cells of pancreatic islets / diabetes mellitus / activin A / TGF-beta / NOD-mice / glucokinase / T細胞 |
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| Research Abstract |
Molecular biological approaches to pancreatic islet B-cells led to following results ;
1.Random cDNA sequencing approach comined with Northern blot analysis to a cultured murine cell line of islet B-cells, yielded abount 20 islet B-cell-specific clones.
Transgenic mice producing immunosuppressive IL-10 or TGF-beta from pancreatic islet A cells were produced.Transgenic expression of IL-10 in NOD mice aggravated autoimmune diabetes. Two strains of TGF-beta-Tg in NOD mice so far did not exhibit diabetes.
Among 5 islet B-cell-specific Th1-lymphoctes, 2 produced IFN-gamma and IL-2, and 3 others produced IL-6 and 10 on top of them. Multiple T-cell functions are necessary for the development of autoimmune diabetes. NOD mice lacking CD40, which is important for T-cell Differentiation, did not become diabetic, suggesting the requirement of CD40 to produce self-reacting T-cells.
Transplantaion of proinsulin-producing fibroblasts with the fail-safety systm of HSV-TK plus ganciclovir, or adoptive transfer of IL-10-transduced lymphocytes with the ability to recognize islet-antigens were used to develop animal models of gene therapy for diabetes.
Because insulin secretion was increased by transduction of hexokinase, and was decreased by expression of antisense mRNA for glucokinase in transgenic mice, glucokinase in islet B-cells is functioning as a glucose-sensitive sensor.
Activin A was detected in the endocrine precursor cells of islets. TGF-beta was detected in pancreatic islet B-cells. Activin A inhibited ATP-sensitive potassium channel, and activated voltage-dependent calcium channels, leading to the increased-insulin secretion. Activin A, in cooperation with betacelluin, induced differentiation of pancreatic exocrine cells of AR42J to insulin-producing cells.
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