From the Departments of Pathology and Developmental Biology, Institute for Stem Cell Biology and Regenerative Medicine, Stanford University School of Medicine, CA (S.R.A.); Department of Internal Medicine, Division of Cardiology, and Broad Stem Cell Research Center, University of California Los Angeles School of Medicine (S.R., M.T., P.Z., A.S., A.H., P.K., Z.T., R.A.); and Division of Blood and Marrow Transplantation, Department of Medicine (A.M. S.M.) and Department of Biology (K.S.V., K.R.-H.), Stanford University, CA.
Circ Res. 2014 Sep 12;115(7):625-35. doi: 10.1161/CIRCRESAHA.115.303794. Epub 2014 Jul 18.
Fibrosis is mediated partly by extracellular matrix-depositing fibroblasts in the heart. Although these mesenchymal cells are reported to have multiple embryonic origins, the functional consequence of this heterogeneity is unknown.
We sought to validate a panel of surface markers to prospectively identify cardiac fibroblasts. We elucidated the developmental origins of cardiac fibroblasts and characterized their corresponding phenotypes. We also determined proliferation rates of each developmental subset of fibroblasts after pressure overload injury.
We showed that Thy1(+)CD45(-)CD31(-)CD11b(-)Ter119(-) cells constitute the majority of cardiac fibroblasts. We characterized these cells using flow cytometry, epifluorescence and confocal microscopy, and transcriptional profiling (using reverse transcription polymerase chain reaction and RNA-seq). We used lineage tracing, transplantation studies, and parabiosis to show that most adult cardiac fibroblasts derive from the epicardium, a minority arises from endothelial cells, and a small fraction from Pax3-expressing cells. We did not detect generation of cardiac fibroblasts by bone marrow or circulating cells. Interestingly, proliferation rates of fibroblast subsets on injury were identical, and the relative abundance of each lineage remained the same after injury. The anatomic distribution of fibroblast lineages also remained unchanged after pressure overload. Furthermore, RNA-seq analysis demonstrated that Tie2-derived and Tbx18-derived fibroblasts within each operation group exhibit similar gene expression profiles.
The cellular expansion of cardiac fibroblasts after transaortic constriction surgery was not restricted to any single developmental subset. The parallel proliferation and activation of a heterogeneous population of fibroblasts on pressure overload could suggest that common signaling mechanisms stimulate their pathological response.
纤维化部分由心脏中细胞外基质沉积的成纤维细胞介导。尽管这些间充质细胞据报道具有多种胚胎起源，但这种异质性的功能后果尚不清楚。
我们试图验证一组表面标志物，以前瞻性地鉴定心脏成纤维细胞。我们阐明了心脏成纤维细胞的发育起源，并对其相应表型进行了表征。我们还确定了每种发育亚群的成纤维细胞在压力超负荷损伤后的增殖率。
我们表明，Thy1(+)CD45(-)CD31(-)CD11b(-)Ter119(-)细胞构成了大多数心脏成纤维细胞。我们使用流式细胞术、荧光显微镜和共聚焦显微镜以及转录谱（使用逆转录聚合酶链反应和 RNA-seq）对这些细胞进行了表征。我们使用谱系追踪、移植研究和联体共生实验表明，大多数成年心脏成纤维细胞来源于心外膜，一小部分来源于内皮细胞，一小部分来源于 Pax3 表达细胞。我们没有发现骨髓或循环细胞产生心脏成纤维细胞。有趣的是，损伤后各亚群成纤维细胞的增殖率相同，损伤后每个谱系的相对丰度保持不变。压力超负荷后成纤维细胞谱系的解剖分布也保持不变。此外，RNA-seq 分析表明，每个手术组内的 Tie2 衍生和 Tbx18 衍生的成纤维细胞表现出相似的基因表达谱。
经主动脉缩窄手术后心脏成纤维细胞的细胞扩增不限于任何单一的发育亚群。在压力超负荷下，异质成纤维细胞的平行增殖和激活可能表明共同的信号机制刺激了它们的病理反应。
