Muscle Development and Regeneration Program, Sanford-Burnham Medical Research Institute, La Jolla, CA 92037, USA.
Cell Stem Cell. 2012 Aug 3;11(2):242-52. doi: 10.1016/j.stem.2012.04.025.
The cellular signals controlling the formation of cardiomyocytes, vascular smooth muscle, and endothelial cells from stem cell-derived mesoderm are poorly understood. To identify these signals, a mouse embryonic stem cell (ESC)-based differentiation assay was screened against a small molecule library resulting in a 1,4-dihydropyridine inducer of type II TGF-β receptor (TGFBR2) degradation-1 (ITD-1). ITD analogs enhanced proteasomal degradation of TGFBR2, effectively clearing the receptor from the cell surface and selectively inhibiting intracellular signaling (IC(50) ~0.4-0.8 μM). ITD-1 was used to evaluate TGF-β involvement in mesoderm formation and cardiopoietic differentiation, which occur sequentially during early development, revealing an essential role in both processes in ESC cultures. ITD-1 selectively enhanced the differentiation of uncommitted mesoderm to cardiomyocytes, but not to vascular smooth muscle and endothelial cells. ITD-1 is a highly selective TGF-β inhibitor and reveals an unexpected role for TGF-β signaling in controlling cardiomyocyte differentiation from multipotent cardiovascular precursors.
细胞信号控制心肌细胞、血管平滑肌和内皮细胞从干细胞衍生中胚层的形成，这些信号的了解甚少。为了鉴定这些信号，对基于小鼠胚胎干细胞（ESC）的分化测定法进行了小分子文库筛选，得到了 II 型 TGF-β受体（TGFBR2）降解-1（ITD-1）的 1,4-二氢吡啶诱导物。ITD 类似物增强了 TGFBR2 的蛋白酶体降解，有效地从细胞表面清除受体，并选择性地抑制细胞内信号（IC（50）~0.4-0.8 μM）。ITD-1 用于评估 TGF-β在中胚层形成和心肌发生分化中的作用，这两个过程在早期发育中是顺序发生的，在 ESC 培养物中揭示了它们在这两个过程中的重要作用。ITD-1 选择性增强了未定型中胚层向心肌细胞的分化，但不能向血管平滑肌和内皮细胞分化。ITD-1 是一种高度选择性的 TGF-β抑制剂，揭示了 TGF-β信号在控制多能心血管前体细胞向心肌细胞分化中的意外作用。
