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。磷脂是肺表面活性物质的主要成分。磷脂的主要类别是磷脂酰胆碱，占磷脂的 70-80%。亲水性表面活性剂相关蛋白 SP-A 和 SP-D 被认为在肺的磷脂代谢和宿主防御机制中发挥重要作用。本研究的目的是探讨SP-A和SP-D在正常肺和患病肺中的作用。1．表面活性蛋白对磷脂代谢的调节。(1)考察了SP-A的生物活性(通过特定受体对II型细胞磷脂分泌的抑制作用)的结构要求。 SP-A 的 C 端抗大学酶片段具有调节磷脂分泌和结合高亲和力受体的能力。阻断 SP-A 活性的人 SP-A 单克隆抗体被发现可以识别 Glu^<202> 的 C 端侧，表明该区域参与与 SP-A 受体的结合。(2) 与脂质形成复合物的天然 SP-D 抵消了 SP-A 对 II 型肺泡细胞磷脂分泌的抑制作用。(3) 配体结合 使用^ 125 I标记的蛋白质作为探针的研究表明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II型细胞对SP-A介导的磷脂酰胆碱(PC)的摄取。当分析 II 型细胞摄取的放射性标记二棕榈酰 PC (DPPC) 的亚细胞分布时，在 SP-A 存在的情况下，在富含板层体的级分中回收了大约 52% 的细胞相关放射性标记 DPPC，而在不存在 SP-A 的情况下，仅在该级分中回收了 19%。结果表明，SP-A有利于DPPC掺入层状体中。 2．表面活性剂蛋白与糖脂的结合特异性。研究了SP-A和SP-D与各种糖脂的直接结合。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。由于细胞表面糖脂是多种微生物的受体，表面活性蛋白与糖脂的结合特性在肺防御系统中显得很重要。 3．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。据信，肺表面活性剂成分仅存在于肺泡腔中，而不是在正常条件下存在于血流中。我们检查了肺病患者的血清中是否出现 SP-A。 IPF患者（205*23 ng/ml，n=32）和PAP患者（285*23 ng/ml，n=6）血清SP-A水平显着高于对照组（45*3 ng/ml，n=56）（平均值*SEM，p<0.01）。较少的

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。