A novel model system for characterization of phagosomal maturation, acidification, and intracellular collagen degradation in fibroblasts
A novel model system for characterization of phagosomal maturation, acidification, and intracellular collagen degradation in fibroblasts
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DOI：
10.1074/jbc.m003221200
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发表时间：
2000-11-10
影响因子：
4.8
通讯作者：
McCulloch, CAG
中科院分区：
文献类型：
--
作者：
Arora, PD;Manolson, MF;McCulloch, CAG
成纤维细胞的细胞内胶原降解是成熟结缔组织生理重塑的一个重要但鲜为人知的途径。本研究的目的是确定表达内源性α (2) β(1)整合素（胶原受体）的牙龈成纤维细胞是否会表现出吞噬体成熟和胶原降解所需的细胞机制。胶原珠内化有时间依赖性的增加，珠相关的α (2) β(1)整合素在初始珠后有时间依赖性的减少；绑定。β -肌动蛋白和凝胶蛋白与微球短暂相关（0-30分钟），其次是LAMP-1（60-240分钟）和组织蛋白酶B（30-240分钟）。细胞chalasin D阻止吞噬体的形成，也阻止早期内体与溶酶体的顺序融合，胶原蛋白珠相关的pH从7.25逐渐降低到5.4，与此同时，胶原蛋白珠相关的降解也逐渐增加（30-120分钟）。康那霉素阻断吞噬溶酶体的酸化和胶原降解，但不阻断吞噬体的成熟，吞噬体的酸化部分依赖于细胞内钙的升高。这些研究表明，成纤维细胞内胶原降解所需的细胞机制与巨噬细胞的空泡系统非常相似。
Intracellular collagen degradation by fibroblasts is an important but poorly understood pathway for the physiological remodeling of mature connective tissues. The objective of this study was to determine whether gingival-fibroblasts that express endogenous alpha (2)beta (1) integrin, the collagen:receptor, would exhibit the cellular machinery required for phagosomal maturation and collagen degradation. There was a time-dependent increase of collagen bead internalization and a time-dependent decrease of bead-associated alpha (2)beta (1) integrin after initial bead; binding. beta -Actin and gelsolin associated transiently with beads (0-30 min) followed by LAMP-1 (60-240 min) and cathepsin B (30-240 min). Cytochalasin D prevented phagosome formation and also prevented the sequential fusion of early endosomes with lysosomes, Collagen bead-associated pH was progressively reduced from: 7.25 to 5.4, which was contemporaneous with progressive increases in degradation of bead-associated collagen (30-120 min). Concanamycin blocked acidification of phagolysosomes and collagen degradation but not phagosome maturation, Phagosomal acidification was partly dependent on elevated intracellular calcium. These studies demonstrate that the cellular machinery required for intracellular collagen degradation in fibroblasts closely resembles the vacuolar system in macrophages.