糖尿病網膜症と血液網膜関門のタイト結合

• Project/Area Number: 12877280
• Research Category: Grant-in-Aid for Exploratory Research
• Allocation Type: Single-year Grants
• Research Field: Ophthalmology
• Research Institution: Sapporo Medical University
• Principal Investigator: 澤田 典均 札幌医科大学, 医学部, 教授 (30154149)
• Co-Investigator(Kenkyū-buntansha): 千葉 英樹 札幌医科大学, 医学部, 講師 (00295346)
• Project Period (FY): 2000 – 2001
• Project Status: Completed (Fiscal Year 2001)
• Budget Amount: ¥2,000,000 (Direct Cost: ¥2,000,000); Fiscal Year 2001: ¥800,000 (Direct Cost: ¥800,000); Fiscal Year 2000: ¥1,200,000 (Direct Cost: ¥1,200,000)
• Keywords: タイト結合 / occludin / 血管内皮細胞 / バリア機能 / アクチン / 血液網膜関門 / 血液脳関門 / GDNF / neurturin / 血液透過性 / TER

Research Abstract

血液脳関門(BBB)と内側血液網膜関門(BRB)は,血管透過性が極めて低く,非常に類似した構造を持ち,調節にも同様な分子機構が働いていると推測される。このような低い血管透過性は,細胞間接着装置のひとつタイト結合のバリア機能によって維持されている.血管内皮細胞のタイト結合は,膜蛋白としてoccludinとclaudin5が知られており,特にoccludinは,他部位の血管に比べBBBやBRBの血管内皮細胞に強く発現していることが知られている.そこで本研究では,occludinの発現が極めて低いラット肺血管内皮細胞(Rat Lung Endothelial cell ; RLE)に,C末端にFLAGを付加したrat occludinを導入し,occludinとタイト結合機能およびアクチン細胞骨格との関係を検討した.Occludin geneを導入し樹立したRLE細胞株では,明らかにoccludin蛋白量が増加し,免疫細胞化学的に細胞接着部位に局在していた.しかしタイト結合機能を示すtransendothelial electric resistance (TER)や,イヌリンやマンニトールの透過性に変化を認めなかった.アクチン細胞骨格を調べるため,EGFP標識wild type RLE (w-RLE)とOccludin導入RLE (o-RLE)をco-cultureし,アクチンの分布を観察した.その結果,w-RLEとw-RLEの接着部位にアクチンの集積を認めないが,o-RLEとo-RLE, o-RLEとw-RLEの接着部位にはアクチンの集積が認められた.逆に,アクチン細胞骨格を破壊すると,occludinは細胞接着部位から消失した.以上から,occludinは,タイト結合のバリア機能の調節より,アクチン細胞骨格とタイト結合を連結する機能を担っていると考えられた.

Research Products

• [Publications] Kubota, H. et al.: "Retinoid X receptor α and retinoic acid receptor γ mediate expression of genes encoding tight junction proteins and barrier function in F9 cells during visceral endoderm differentiation"Exp. Cell. Res.. 263. 163-179 (2001)
• [Publications] Kojima, T. et al.: "Occludin and claudin-1 concentrate in the midbody of immortalized mouse hepatocytes during cell division"J. Histochem. Cytochem.. 49. 333-339 (2001)
• [Publications] Kojima, T. et al.: "Cx32 but not Cx26 is associated with tight junctions in primary cultures of rat hepatocytes"Exp. Cell. Res.. 263. 193-201 (2001)
• [Publications] Kuwabara, H. et al.: "Occludin regulates actin cytoskeleton in endothelial cells"Cell Struct. Funct.. 26. 109-116 (2001)
• [Publications] Kojima, T. et al.: "Growth-suppressive function of human connexin32 in a conditional immortalized mouse hepatocyte cell line"In Vitro Cell Dev. Biol.. 37. 589-598 (2001)
• [Publications] Takakuwa, Y. et al.: "Bile canalicular barrier function and expression of tight junctional molecules in rat hepatocytes during common bile duct ligation"Cell Tissue Res.. (In press).
• [Publications] Kojima, T. et al.: "The Liver : Biology an Pathobiology, Fourth Edition, deited by Arias, I.M. et al., (Gap and tight junctions in liver : composition, regulation, and function)"Lippincott Williams & Wilkins, Philadelphia. 29-46/1064 (2001)
• [Publications] Utsumi,H. et.al.: "Expression of GFR α 1-, receptor for GDNF, in rat brain capillary during postnatal development of the BBB."Am.J.Physiol.Cell Physiol.. 279. C361-C368 (2000)
• [Publications] Takakuwa,R. et.al.: "Uncoupling of gate and fence functions of MDCK cells by the actin depolymerizing reagent mycalolide B."Exp.Cell.Res.. 257. 238-244 (2000)
• [Publications] Igarashi,Y. et. al.: "Expression of receptors for glial cell line-derived neurotrophic factor (GDNF) and neurturin in the inner blood-retinal barrier of rats."Cell Struct.Funct.. 25. 215-219 (2000)
• [Publications] Kubota,H.: "Retinoid X receptor α and retinoic acid receptor γ mediate expression of genes encoding tight junction proteins and barrier function in F9 cells during visceral endoderm differentiation."Exp.Cell.Res.. (印刷中). (2000)
• [Publications] 澤田典均 他: "血管透過性亢進の細胞学的側面-血液網膜関門と神経栄養因子GDNF-"日本眼科紀要. (印刷中). (2000)