Fietta Am, Bardoni Am, Salvini R, Passadore I, Morosini M, Cavagna L, Codullo V, Pozzi E, Meloni F, Montecucco C
Department of Haematological, Pneumological and Cardiovascular Sciences, University of Pavia, Via Taramelli 5, 27100 Pavia, Italy.
Arthritis Res Ther. 2006;8(6):R160. doi: 10.1186/ar2067.
Lung fibrosis is a major cause of mortality and morbidity in systemic sclerosis (SSc). However, its pathogenesis still needs to be elucidated. We examined whether the alteration of certain proteins in bronchoalveolar lavage fluid (BALF) might have a protective or a causative role in the lung fibrogenesis process. For this purpose we compared the BALF protein profile obtained from nine SSc patients with lung fibrosis (SScFib+) with that obtained from six SSc patients without pulmonary fibrosis (SScFib-) by two-dimensional gel electrophoresis (2-DE). Only spots and spot-trains that were consistently expressed in a different way in the two study groups were taken into consideration. In total, 47 spots and spot-trains, corresponding to 30 previously identified proteins in human BALF, showed no significant variation between SScFib+ patients and SScFib- patients, whereas 24 spots showed a reproducible significant variation in the two study groups. These latter spots corresponded to 11 proteins or protein fragments, including serum albumin fragments (13 spots), 5 previously recognized proteins (7 spots), and 4 proteins (3 spots) that had not been previously described in human BALF maps, namely calumenin, cytohesin-2, cystatin SN, and mitochondrial DNA topoisomerase 1 (mtDNA TOP1). Mass analysis did not determine one protein-spot. The two study groups revealed a significant difference in BALF protein composition. Whereas levels of glutathione S-transferase P (GSTP), Cu-Zn superoxide dismutase (SOD) and cystatin SN were downregulated in SScFib+ patients compared with SScFib- patients, we observed a significant upregulation of alpha1-acid glycoprotein, haptoglobin-alpha chain, calgranulin (Cal) B, cytohesin-2, calumenin, and mtDNA TOP1 in SScFib+ patients. Some of these proteins (GSTP, Cu-Zn SOD, and cystatin SN) seem to be involved in mechanisms that protect lungs against injury or inflammation, whereas others (Cal B, cytohesin-2, and calumenin) seem to be involved in mechanisms that drive lung fibrogenesis. Even if the 2-DE analysis of BALF did not provide an exhaustive identification of all BALF proteins, especially those of low molecular mass, it allows the identification of proteins that might have a role in lung fibrogenesis. Further longitudinal studies on larger cohorts of patients will be necessary to assess their usefulness as predictive markers of disease.
肺纤维化是系统性硬化症（SSc）患者死亡和发病的主要原因。然而，其发病机制仍有待阐明。我们研究了支气管肺泡灌洗液（BALF）中某些蛋白质的改变在肺纤维化形成过程中是否具有保护作用或致病作用。为此，我们通过二维凝胶电泳（2-DE）比较了9例肺纤维化系统性硬化症患者（SScFib+）和6例无肺纤维化系统性硬化症患者（SScFib-）的BALF蛋白质谱。仅考虑在两个研究组中以不同方式持续表达的斑点和斑点序列。总共，47个斑点和斑点序列，对应于人类BALF中先前鉴定的30种蛋白质，在SScFib+患者和SScFib-患者之间没有显著差异，而24个斑点在两个研究组中表现出可重复的显著差异。后一组斑点对应于11种蛋白质或蛋白质片段，包括血清白蛋白片段（13个斑点）、5种先前识别的蛋白质（7个斑点）和4种在人类BALF图谱中未被先前描述的蛋白质（3个斑点），即钙网蛋白、细胞粘附素-2、半胱氨酸蛋白酶抑制剂SN和线粒体DNA拓扑异构酶1（mtDNA TOP1）。质谱分析未确定一种蛋白质斑点。两个研究组在BALF蛋白质组成上显示出显著差异。与SScFib-患者相比，SScFib+患者中谷胱甘肽S-转移酶P（GSTP）、铜锌超氧化物歧化酶（SOD）和半胱氨酸蛋白酶抑制剂SN的水平下调，而我们观察到SScFib+患者中α1-酸性糖蛋白、触珠蛋白α链、钙粒蛋白（Cal）B、细胞粘附素-2、钙网蛋白和mtDNA TOP1显著上调。其中一些蛋白质（GSTP、铜锌SOD和半胱氨酸蛋白酶抑制剂SN）似乎参与了保护肺免受损伤或炎症的机制，而其他蛋白质（Cal B、细胞粘附素-2和钙网蛋白）似乎参与了驱动肺纤维化的机制。即使对BALF进行二维凝胶电泳分析不能详尽鉴定所有BALF蛋白质，尤其是低分子量蛋白质，但它能够鉴定出可能在肺纤维化形成中起作用的蛋白质。有必要对更多患者队列进行进一步的纵向研究，以评估它们作为疾病预测标志物的实用性。
