Palpant Nathan J, Wang Yuliang, Hadland Brandon, Zaunbrecher Rebecca J, Redd Meredith, Jones Daniel, Pabon Lil, Jain Rajan, Epstein Jonathan, Ruzzo Walter L, Zheng Ying, Bernstein Irwin, Margolin Adam, Murry Charles E
Department of Pathology, University of Washington School of Medicine, Seattle, WA 98109, USA; Center for Cardiovascular Biology, University of Washington School of Medicine, Seattle, WA 98109, USA; Institute for Stem Cell and Regenerative Medicine, University of Washington School of Medicine, Seattle, WA 98109, USA.
Department of Computer Science, University of Washington School of Medicine, Seattle, WA 98109, USA.
Cell Rep. 2017 Aug 15;20(7):1597-1608. doi: 10.1016/j.celrep.2017.07.067.
We analyzed chromatin dynamics and transcriptional activity of human embryonic stem cell (hESC)-derived cardiac progenitor cells (CPCs) and KDR/CD34 endothelial cells generated from different mesodermal origins. Using an unbiased algorithm to hierarchically rank genes modulated at the level of chromatin and transcription, we identified candidate regulators of mesodermal lineage determination. HOPX, a non-DNA-binding homeodomain protein, was identified as a candidate regulator of blood-forming endothelial cells. Using HOPX reporter and knockout hESCs, we show that HOPX regulates blood formation. Loss of HOPX does not impact endothelial fate specification but markedly reduces primitive hematopoiesis, acting at least in part through failure to suppress Wnt/β-catenin signaling. Thus, chromatin state analysis permits identification of regulators of mesodermal specification, including a conserved role for HOPX in governing primitive hematopoiesis.
我们分析了源自人胚胎干细胞（hESC）的心脏祖细胞（CPC）以及由不同中胚层来源产生的KDR/CD34内皮细胞的染色质动力学和转录活性。我们使用一种无偏差算法对在染色质和转录水平上受到调控的基因进行分层排序，从而鉴定出中胚层谱系决定的候选调节因子。HOPX是一种非DNA结合型同源结构域蛋白，被鉴定为造血内皮细胞的候选调节因子。通过使用HOPX报告基因和基因敲除的hESC，我们发现HOPX调节血液生成。HOPX的缺失不会影响内皮细胞命运的特化，但会显著减少原始造血，至少部分是通过无法抑制Wnt/β-连环蛋白信号传导来实现的。因此，染色质状态分析能够鉴定中胚层特化的调节因子，包括HOPX在调控原始造血过程中的保守作用。
