THE ROLE OF FRAGMENTED FIBRONECTIN IN THE MESANGIAL IGA-DEPOSITION AND PROLIFERATION IN IGA NEPHROPATHY.

纤维连接蛋白片段在 IGA 肾病系膜 IGA 沉积和增殖中的作用。

• 批准号: 07670833
• 负责人: WAGA Shinobu
• 金额: $ 0.13万
• 依托单位: HIROSAKI UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1995
• 资助国家: 日本
• 起止时间: 1995 至 1996
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07670833/
• 关键词: IgA nephropathy; matrix-assembly; C-terminal fragmented fibronectin; fragmented fibronectin; IgA-fibronectin complex; フィブロネクチン; IgA

BackgroundsImmunoglobulin A (IgA) deposition in the glomerular mesangial matrix is a prerequisite for the diagnosis of IgA nephropathy, and circulating IgA-containing complex has been implicated in this process. Composition of these complexes has been extensively studied, but fragmented fibronectin has not been reported. Since fragmented fibronectin by itself is known to be involved in the assembly of extracellular matrix, we investigated whether fragmented fibronectin exists in patient's serum and is capable of binding IgA.MethodsSerum from patients with IgA nephropathy was applied to heparin-affinity column and the effluent was analyzed by Western-blot technique with a set of anti-human fibronectin monoclonal antibodies. Native fibronectin was digested with cathepsin D to obtain fragment similar to that of serum fibronectin, and the capacity of fibronectin to bind IgA was modeled with a mixture ofpurified IgA1 and cathepsin D-digested fibronectin using affinity purification on jacalin-agarose.FindingsA fragment at about 43 kDa reacted only in the patients with antibody FN 1-1, which is specific to the carboxyl-terminal region of fibronectin containing a disulfide bond. A similar-sized fragment was generated by cathepsin D-digestion of the native molecule and was bound to IgA1 in vitro.InterpretationThis study demonstrates that about a 43 kDa carboxylterminal fragment of fibronectin was able to bind IgA1 and a fragment of similar size was present in patients'sera. Since the carboxyl-terminal disulfide bond is known to be critical in assembling exogenous fibronectin into the extracellular matrix, the affinity of IgA1 to a fragment found in patients may have pathogenic potential to participate in extracellular expansion and IgA-deposition in IgA nephropathy.

免疫球蛋白A（伊加）在肾小球系膜基质中的沉积是伊加肾病诊断的前提，而循环中IgA复合物的存在与这一过程有关。这些复合物的组成已被广泛研究，但片段化的纤连蛋白尚未报道。由于片段化的纤连蛋白本身是已知的参与组装的细胞外基质，我们调查是否片段化的纤连蛋白存在于患者的血清中，并能够结合伊加.MethodsSerum从伊加肾病患者应用肝素亲和柱和流出物进行了分析，通过Western印迹技术与一组抗人纤连蛋白单克隆抗体。用组织蛋白酶D消化天然纤连蛋白，获得与血清纤连蛋白相似的片段，用纯化的IgA 1和组织蛋白酶D消化的纤连蛋白的混合物，用jacalin-琼脂糖亲和纯化法模拟纤连蛋白结合伊加的能力。其特异于含有二硫键的纤连蛋白的羧基末端区域。通过组织蛋白酶D消化天然分子产生类似大小的片段，并与IgA 1在vitro.InterpretationThis研究表明，约43 kDa的纤维连接蛋白的羧基末端片段能够结合IgA 1和类似大小的片段存在于患者的血清中。由于羧基末端的二硫键是已知的组装外源性纤连蛋白到细胞外基质中的关键，在患者中发现的片段的IgA 1的亲和力可能有致病性的潜力，参与细胞外扩张和IgA沉积在伊加肾病。

项目成果

Tanaka,H: "Capaciyty of H_2O_2 release from monocytes in steroid-sensitive nephrotic syndrome" Tohoku J.Exp.Med.(印刷中). (1996)

Tanaka, H：“类固醇诱导的肾病综合征中单核细胞释放 H_2O_2 的能力”Tohoku J.Exp.Med（出版中）。

Waga, S. et al.: "Frgmentation of Fibronectin in the serum from IgA nephropathy and binding of IgA1 to fragmented fibronectin." J. Am. Soc. Mephrol.6. 931- (1995)

Waga, S. 等人：“IgA 肾病血清中纤连蛋白的片段化以及 IgA1 与片段化纤连蛋白的结合。”

Waga,S: "Fragmentation of fibronectin in the serum from IgA nephropathy and binding of IgA,fagmented fibronectine." J.Am.Soc.Nephrol. 6. 931 (1995)

Waga,S：“IgA 肾病血清中纤连蛋白的片段化以及 IgA 的结合，片段化的纤连蛋白。”

WAGA,S.ET AL.: "FRAGMENTATION OF FIBRONECTIN IN THE SERUM FROM IGA NEPHROPATHY AND BINDING OF IGA1 TO FRAGMENTED FIBRONECTIN." J AM SOC NEPHROL. 6. 931 (1995)

WAGA,S.ET AL.：“IGA 肾病血清中纤连蛋白的碎片以及 IGA1 与碎片纤连蛋白的结合。”

Tanaka,H.and Waga,S.et al.: "Capacity of H_2O_2 release from monocytes in stersid sensitive nephotic syndrome." Tohoku J.Exp.Med.178. 271-277 (1996)

Tanaka,H.and Waga,S.et al.：“类固醇敏感性肾病综合征中单核细胞释放 H_2O_2 的能力”。