Moodley Yuben P, Caterina Paul, Scaffidi Amelia K, Misso Neil L, Papadimitriou John M, McAnulty Robin J, Laurent Geoffrey J, Thompson Philip J, Knight Darryl A
Asthma and Allergy Research Institute, Sir Charles Gairdner Hospital, Nedlands, Western Australia, Australia.
J Pathol. 2004 Apr;202(4):486-95. doi: 10.1002/path.1531.
It is increasingly recognized that the morphological changes of apoptosis vary between cell types. This heterogeneity reflects the wide range of cellular proteins and enzymes involved in apoptotic pathways. Fibroblast apoptosis is crucial to the regression of scars and the restitution of healthy tissue during wound repair and may be aberrant in diseases such as idiopathic pulmonary fibrosis (IPF). The biochemical and morphological changes characterizing fibroblast apoptosis are unknown and may provide insights into the specific enzymatic mediators activated in these cells. This study aimed to examine the morphological changes of fibroblast apoptosis in both primary normal lung fibroblasts (normal-Fb) and fibroblasts obtained from patients with idiopathic pulmonary fibrosis (IPF-Fb) and to correlate these changes with conventional biochemical markers. Transmission electron microscopy (TEM) and video time-lapse microscopy demonstrated no difference in the duration of fibroblast apoptosis in response to FasL (6 +/- 0.3 h in normal-Fb and 6.4 +/- 0.2 h in IPF-Fb). However, IPF-Fb were more resistant to FasL-induced apoptosis compared with normal-Fb. Although the majority of morphological changes of normal-Fb and IPF-Fb were similar, the formation of filopodia and condensation of the cytoskeletal bundles in IPF-Fb, and more prominent vacuolation in normal-Fb, were the significant differences between these cell subtypes. Loss of the mitochondrial membrane potential occurred prior to caspase-3 activation, while phosphatidylserine expression, cytokeratin-18 cleavage, and DNA fragmentation commenced after caspase-3 activation. These observations not only suggest that specific enzymatic effectors may be preferentially activated during fibroblast apoptosis, but also provide potential insights into the pathogenesis of IPF.
人们越来越认识到，细胞凋亡的形态学变化因细胞类型而异。这种异质性反映了参与凋亡途径的多种细胞蛋白和酶。成纤维细胞凋亡对于伤口修复过程中瘢痕的消退和健康组织的恢复至关重要，而在特发性肺纤维化（IPF）等疾病中可能异常。成纤维细胞凋亡的生化和形态学变化尚不清楚，可能有助于深入了解这些细胞中激活的特定酶介质。本研究旨在检查原代正常肺成纤维细胞（正常-Fb）和特发性肺纤维化患者来源的成纤维细胞（IPF-Fb）中，成纤维细胞凋亡的形态学变化，并将这些变化与传统生化标志物相关联。透射电子显微镜（TEM）和视频延时显微镜显示，正常-Fb和IPF-Fb对FasL反应的成纤维细胞凋亡持续时间没有差异（正常-Fb为6±0.3小时，IPF-Fb为6.4±0.2小时）。然而，与正常-Fb相比，IPF-Fb对FasL诱导的凋亡更具抗性。尽管正常-Fb和IPF-Fb的大多数形态学变化相似，但IPF-Fb中丝状伪足的形成和细胞骨架束的凝聚，以及正常-Fb中更明显的空泡化，是这些细胞亚型之间的显著差异。线粒体膜电位的丧失发生在caspase-3激活之前，而磷脂酰丝氨酸表达、细胞角蛋白-18裂解和DNA片段化在caspase-3激活后开始。这些观察结果不仅表明在成纤维细胞凋亡过程中特定的酶效应器可能被优先激活，而且还为IPF的发病机制提供了潜在的见解。
