Regulatory roles of pulmonary surfactant apoprotein and its receptor in metabolism of lung diseases.

肺表面活性物质脱辅基蛋白及其受体在肺部疾病代谢中的调节作用。

• 批准号: 03670406
• 负责人: KUROKI Yoshio
• 金额: $ 1.28万
• 依托单位: Sapporo Medical College
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1991
• 资助国家: 日本
• 起止时间: 1991 至 1992
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-03670406/
• 关键词: Pulmonary Surfactant; Phospholipid Metabolism; Alveolar Type II Cells; Surfactant Apoproteins; Phosphatidylcholine; Phosphatidylinositol; Respiratory Function; Glycolipids; 肺サ-ファクタント・アポ蛋白質; ホスファチジルイノシト-ル

Pulmonary surfactant is a complex mixture of lipids and proteins synthesized and secreted by alveolar type II cells. Phospholipids are the major components of pulmonary surfactant. The major class of phospholipids is phosphatidylcholine, which constitutes 70-80 % of phospholipids. The hydrophilic surfactant-associated proteins, SP-A and SP-D, are believed to play important roles in phospholipid metabolism and host-defense mechanism in the lung. The purpose of the present study was to investigate the roles of SP-A and SP-D in normal and diseased lungs.1. Regulation of phospholipid metabolism by surfactant proteins.(1) Structural requirement of SP-A for its biological activity (the inhibitory effect on phospholipid secretion by type II cells via a specific receptor) was examined. The C-terminal collegenase-resistent fragment of SP-A possessed the ability to regulate phospholipid secretion and to bind a high affinity receptor. Monoclonal antibody to human SP-A that blocked the SP-A activi … More ty was found to recognize the C-terminal side from Glu^<202>, suggesting the involvement of this region with the binding to SP-A receptor.(2) Native SP-D that formed a comlex with lipid counteracted the inhibitory effect of SP-A on phospholipid secretion by alveolar type II cells.(3) The ligand binding studies using ^<125>l-labeled proteins as probes revealed that SP-A and SP-D bound to phosphatidylcholine and phosphatidylinostitol, respectively.(4) SP-A-mediated uptake of phosphatidylcholine (PC) by type II cells was investigated. When subcellular distribution of radiolabeled dipalmitoyl PC (DPPC) taken up by type II cells was analyzed, approximately 52 % of cell-associated radiolabeled DPPC was recovered in the lamellabody-rich fraction in the presence of SP-A, whereas only 19 % was found to this fraction in the absence of SP-A. The result indicates that SP-A facilitates the incorporation of DPPC into lamellar bodies.2. Binding specificities of surfactant proteins for glycolipids.The direct binding of SP-A and SP-D to various glycolipids was investigated. SP-A was found to bind to galactosylceramide and asialo GM2. SP-D bound to glucosylceramide. The binding property of surfactant proteins to glycolipids appeas important in pulmonary defense system since cell surface glycolipids serve as receptors for various microorganism.3. Appearance of SP-A in the sera from patients with idiopathic pulmonary fibrosis (IPF) and pulmonary alveolar proteinosis (PAP). Lung surfactant components are believed to be present exclusively in the alveolar spaces and not in the blood stream under normal conditions. We examined whether SP-A appears in the sera of patients with lung diseases. The serum SP-A levels in patients with IPF (205*23 ng/ml, n=32) and PAP (285*23 ng/ml, n=6) were significantly higher than those in control subjects (45*3 ng/ml, n=56) (mean*SEM, p<0.01). Less

肺表面活性物质是由肺泡II型细胞合成和分泌的脂质和蛋白质的复杂混合物。磷脂是肺表面活性剂的主要成分。磷脂的主要种类是磷脂酰胆碱，占磷脂的70- 80%。亲水表面活性剂相关蛋白SP-A和SP-D被认为在肺磷脂代谢和宿主防御机制中发挥重要作用。本研究旨在探讨SP-A和SP-D在正常和病变肺中的作用。表面活性剂蛋白对磷脂代谢的调节。(1)考察了SP-A生物活性的结构要求（通过特定受体抑制II型细胞分泌磷脂的作用）。SP-A的c端抗大学生酶片段具有调节磷脂分泌和结合高亲和力受体的能力。该单克隆抗体可阻断SP-A的活性，更多的ty可识别Glu^<202>的c端，提示该区域与SP-A受体结合有关。(2)天然SP-D与脂质形成复合物，抵消SP-A对肺泡II型细胞分泌磷脂的抑制作用。(3)以^<125>l标记蛋白为探针进行配体结合研究，发现SP-A和SP-D分别与磷脂酰胆碱和磷脂酰肌醇结合。(4)研究了sp - a介导的II型细胞对磷脂酰胆碱（PC）的摄取。当分析II型细胞吸收的放射性标记双棕榈酰PC （DPPC）的亚细胞分布时，在SP-A存在时，在富含片层体的部分中回收了大约52%的细胞相关放射性标记DPPC，而在SP-A不存在时，该部分仅发现19%。结果表明，SP-A促进了DPPC在片层体中的掺入。表面活性剂蛋白对糖脂的结合特异性。研究了SP-A和SP-D与多种糖脂的直接结合。发现SP-A与半乳糖神经酰胺和asialo GM2结合。SP-D与葡萄糖神经酰胺结合。表面活性剂蛋白与糖脂的结合特性在肺防御系统中显得很重要，因为细胞表面的糖脂可以作为多种微生物的受体。特发性肺纤维化（IPF）和肺泡蛋白沉积症（PAP）患者血清中SP-A的出现在正常情况下，肺表面活性成分被认为只存在于肺泡间隙而不存在于血流中。我们检查了SP-A是否出现在肺部疾病患者的血清中。IPF患者血清SP-A水平（205*23 ng/ml, n=32）和PAP患者血清SP-A水平（285*23 ng/ml, n=6）显著高于对照组（45*3 ng/ml, n=56）（平均*SEM， p<0.01）。少

项目成果

Noriharu Shijubo: "Pulmonary Surfactant Protein A in Pleural Effusions" Cancer. 69. 2905-2909 (1992)

Noriharu Shijubo：“胸腔积液中的肺表面活性蛋白 A”癌症。

Yoshinori Ogasawara: "Ontogeny of surfactant protein D, SP-D, in the rat lung." Biochim. Biophys. Acta. 1083. 252-256 (1991)

Yoshinori Ogasawara：“大鼠肺中表面活性蛋白 D、SP-D 的个体发育。”

Yoshio Kuroki: "Pulmonary Surfactant Protein A(SPーA)Specifically Binds Dipalmitoylphosphatidylcholine." J.Biol.Chem.266. 3068-3073 (1991)

Yoshio Kuroki：“肺表面活性剂蛋白 A (SP-A) 特异性结合二棕榈酰磷脂酰胆碱。”J.Biol.Chem.266 3068-3073 (1991)。

Yoshio Kuroki: "Surfactant Protein D(SPーD)Counteracts the Inhibitory Effect of Surfactant Protein A(SPーA)on Phospholipid Secretion by Alveolar Type II Cells" Biochem.J.279. 115-119 (1991)

Yoshio Kuroki：“表面活性剂蛋白 D (SP-D) 抵消表面活性剂蛋白 A (SP-A) 对肺泡 II 型细胞磷脂分泌的抑制作用”Biochem.J.279 (1991)。

Yoshio Kuroki: "Surfactant Protein D(SP-D)Counteracts the Inhibitory Effect of Surfactant Protein A(SP-A)on Phospholipid Secretion by Alveolar Type II Cells" Biochem.J.279. 115-119 (1991)

Yoshio Kuroki：“表面活性剂蛋白 D(SP-D) 抵消表面活性剂蛋白 A(SP-A) 对肺泡 II 型细胞磷脂分泌的抑制作用”Biochem.J.279。