Clancy Robert M, Askanase Anca D, Kapur Raj P, Chiopelas Efstathia, Azar Natalie, Miranda-Carus M Eugenia, Buyon Jill P
Department of Rheumatology, Hospital for Joint Diseases, New York University School of Medicine, New York, NY 10003, USA.
J Immunol. 2002 Aug 15;169(4):2156-63. doi: 10.4049/jimmunol.169.4.2156.
The signature lesion of autoantibody-associated congenital heart block (CHB) is fibrosis of the conducting tissue. To date, participation of myofibroblasts in the cascade to injury has been unexplored. The importance of myofibroblast/macrophage cross-talk is demonstrated by the novel finding of these cell types in the heart of a neonate dying of CHB. This clue to pathogenesis prompted consideration of the mechanism by which maternal anti-SSA/Ro-SSB/La Abs initiate an inflammatory response and promote fibrosis. Isolated cardiocytes from 16-24 wk abortuses were rendered apoptotic by exposure to poly (2-) hydroxyethylmethacrylate; flow cytometry confirmed surface expression of Ro/La. Apoptotic cardiocytes were incubated with affinity-purified Abs to 52 and 60 kDa Ro from CHB mothers (opsonized) or IgG fractions from healthy donors (nonopsonized). Macrophages cultured with opsonized apoptotic cardiocytes expressed proinflammatory markers, supported by a three-fold increase in active alpha(V)beta(3) integrin. Fetal cardiac fibroblasts exposed to supernatants obtained from macrophages incubated with opsonized apoptotic cardiocytes (but not nonopsonized) dramatically increased expression of the myofibroblast marker alpha-smooth muscle actin (SMAc). The "opsonized" supernatant reversed an inhibitory effect of the "nonopsonized" supernatant on proliferation of fibroblasts (120 vs 69%, p < 0.05). Parallel experiments examined the effects of two cytokines and their neutralizing Abs on fibroblasts. TGFbeta1 increased SMAc staining but decreased proliferation. TNF-alpha did not affect either readout. Addition of anti-TGFbeta1 Abs to the "opsonized" supernatant blocked SMAc expression but increased proliferation, while anti-TNF-alpha blocking Abs had no effects. These data suggest that transdifferentiation of cardiac fibroblasts to a scarring phenotype is a pathologic process initiated by maternal Abs.
自身抗体相关先天性心脏传导阻滞（CHB）的标志性病变是传导组织的纤维化。迄今为止，肌成纤维细胞在损伤级联反应中的参与情况尚未得到研究。在一名死于CHB的新生儿心脏中发现了这些细胞类型，这一新颖发现证明了肌成纤维细胞/巨噬细胞相互作用的重要性。这一致病机制线索促使人们思考母体抗SSA/Ro-SSB/La自身抗体引发炎症反应并促进纤维化的机制。将16 - 24周流产胎儿的分离心肌细胞暴露于聚（2 -）羟乙基甲基丙烯酸酯中使其凋亡；流式细胞术证实了Ro/La的表面表达。将凋亡心肌细胞与来自CHB母亲的针对52和60 kDa Ro的亲和纯化抗体（调理过的）或来自健康供体的IgG组分（未调理过的）一起孵育。与调理过的凋亡心肌细胞一起培养的巨噬细胞表达促炎标志物，活性α（V）β（3）整合素增加了三倍，这支持了这一结果。暴露于与调理过的凋亡心肌细胞一起培养的巨噬细胞获得的上清液（而非未调理过的上清液）中的胎儿心脏成纤维细胞，其肌成纤维细胞标志物α - 平滑肌肌动蛋白（SMAc）的表达显著增加。“调理过的”上清液逆转了“未调理过的”上清液对成纤维细胞增殖的抑制作用（120%对69%，p < 0.05）。平行实验研究了两种细胞因子及其中和抗体对成纤维细胞的影响。转化生长因子β1（TGFβ1）增加了SMAc染色，但降低了增殖。肿瘤坏死因子α（TNF - α）对这两种指标均无影响。向“调理过的”上清液中添加抗TGFβ1抗体可阻断SMAc表达，但增加了增殖，而抗TNF - α阻断抗体则无作用。这些数据表明，心脏成纤维细胞向瘢痕形成表型的转分化是由母体自身抗体引发 的病理过程。
