Clark J G, Dedon T F, Wayner E A, Carter W G
Fred Hutchinson Cancer Research Center, Seattle, Washington 98104, USA.
J Clin Invest. 1989 May;83(5):1505-11. doi: 10.1172/JCI114045.
We used cultured human diploid lung fibroblasts as a model system to examine the effects of recombinant IFN-gamma on synthesis of collagen, matrix deposition of newly synthesized collagen, and the expression of cell surface receptors for collagen. Using [3H]proline-labeled cells we found that IFN-gamma resulted in dose-dependent inhibition of fibroblast collagen synthesis. Pulse-chase experiments to analyze compartmentalization of newly synthesized collagen showed that the decrease in collagen synthesis was confined to the soluble pool of procollagen in the medium, while extracellular matrix associated collagen was not changed, indicating that a larger proportion of newly synthesized collagen was deposited into the matrix in IFN-gamma exposed fibroblasts (34.2 vs. 25.3%). This increase in the efficiency of collagen matrix deposition was associated with enhanced expression of a cell surface receptor for collagen as detected by indirect immunofluorescence labeling and analysis by flow cytometry. Fibroblasts (IMR-90) cultured in the presence of IFN-gamma (1,000 U/ml) exhibited a twofold increase in mean linear fluorescence intensity compared with cells cultured under control conditions. The distribution of log fluorescence intensity in both control and IFN-gamma exposed cells was normally distributed about the mean, indicating that discrete subpopulations with respect to receptor expression were not present. Increased fluorescence intensity and log normal distribution of fluorescence intensity also were identified in IFN-gamma-treated lung fibroblasts from a normal adult individual and two strains obtained from patients with pulmonary fibrosis. These results indicate that IFN-gamma modulates fibroblast collagen matrix deposition as well as collagen synthesis. The associated increase in collagen receptors suggests that cytokine-mediated modulation of the cell surface maybe a contributing factor in regulation of fibroblast collagen accumulation in the extracellular matrix or in cellular interaction with collagen-containing matrix. Such an effect could modulate the interaction of fibroblasts with extracellular matrix at sites of inflammation and play an important role in the remodeling of matrix during repair from tissue injury.
我们使用培养的人二倍体肺成纤维细胞作为模型系统，来研究重组干扰素-γ对胶原蛋白合成、新合成胶原蛋白的基质沉积以及胶原蛋白细胞表面受体表达的影响。利用[³H]脯氨酸标记的细胞，我们发现干扰素-γ导致成纤维细胞胶原蛋白合成呈剂量依赖性抑制。脉冲追踪实验分析新合成胶原蛋白的区室化显示，胶原蛋白合成的减少仅限于培养基中可溶性原胶原池，而细胞外基质相关胶原蛋白未发生变化，这表明在暴露于干扰素-γ的成纤维细胞中，更大比例的新合成胶原蛋白沉积到了基质中（34.2%对25.3%）。胶原蛋白基质沉积效率的这种提高与通过间接免疫荧光标记和流式细胞术分析检测到的胶原蛋白细胞表面受体表达增强有关。在干扰素-γ（1000 U/ml）存在下培养的成纤维细胞（IMR-90）与对照条件下培养的细胞相比，平均线性荧光强度增加了两倍。对照细胞和暴露于干扰素-γ的细胞中对数荧光强度的分布均围绕平均值呈正态分布，表明不存在受体表达方面的离散亚群。在来自一名正常成年人以及从两名肺纤维化患者获得的两个菌株的经干扰素-γ处理的肺成纤维细胞中，也鉴定出了荧光强度增加和荧光强度对数正态分布。这些结果表明，干扰素-γ调节成纤维细胞胶原蛋白基质沉积以及胶原蛋白合成。胶原蛋白受体的相关增加表明，细胞因子介导的细胞表面调节可能是调节细胞外基质中纤维母细胞胶原蛋白积累或细胞与含胶原蛋白基质相互作用的一个促成因素。这种效应可以调节炎症部位成纤维细胞与细胞外基质的相互作用，并在组织损伤修复过程中的基质重塑中发挥重要作用。
