Self-renewal of embryonic stem cells by a small molecule

Abstract

A cell-based screen of chemical libraries was carried out to identify small molecules that control the self-renewal of ES cells. A previously uncharacterized heterocycle, SC1, was discovered that allows one to propagate murine ES cells in an undifferentiated, pluripotent state under chemically defined conditions in the absence of feeder cells, serum, and leukemia inhibitory factor. Long-term SC1-expanded murine ES cells can be differentiated into cells of the three primary germ layers in vitro and also can generate chimeric mice and contribute to the germ line in vivo. Biochemical and cellular experiments suggest that SC1 works through dual inhibition of RasGAP and ERK1. Molecules of this kind may not only facilitate practical applications of stem cells in research and therapy, but also provide previously undescribed insights into the complex biology of stem cells.

Chemical approaches to studying stem cell biology

“…Addition of another small molecule inhibitor of GSK3 (CHIR99021 in this case), which had previously been shown to support ESC self-renewal, results in the maintenance of a "ground state" self-renewal without activating classic self-renewal pathways including LIF/STAT3 and BMP4/SMAD pathways. This study supported the notion that mESCs have an "innate" ability to self-renew when shielded from differentiation-inducing signals [11]. Similarly, the combinations of factors that inhibit differentiation signaling pathways in conjunction with LIF supported the derivation and long-term self-renewal of mESCs from refractory strains [54,55], rat ESCs and rat induced pluripotent stem cells [56][57][58][59].…”

“…Previous studies suggested that the ERK/mitogenactivated protein kinase (MAPK) pathway plays a negative role in mESC self-renewal [11,52]. Based on this prior knowledge, Ying et al [53] found that application of MAPK/ERK kinase (MEK) and/or fibroblast growth factor (FGF) receptor inhibitors can prevent mESC differentiation under defined conditions without LIF supplementation.…”

“…However, whether or not there are other deterministic mechanisms was unknown. From a high-throughput screening of novel small molecule libraries, we identified a new 3,4-dihydropyrimido (4,5-d) pyrimidine analog named pluripotin/SC1 that could maintain mESCs in the undifferentiated, pluripotent state under chemically defined conditions in the absence of feeder cells, serum, LIF and BMP4 [11]. Mechanism studies revealed that pluripotin directly interacts with and inhibits the differentiation-inducing signaling components extracellular signal-regulated kinases (ERK) and Ras GTPase activating protein, without affecting the classic mESC self-renewal pathways, including LIF/ STAT3, BMP4/SMAD or Wnt/β-catenin signaling.…”

Chemical Biology of Pluripotent Stem Cells: Focus on Cardiomyogenesis

“…In a high-throughput chemical screen, Ding and colleagues identified a novel molecule, Pluripotin/SC1, which was useful for maintaining long-term self-renewal of mouse ES cells (mESCs) in the absence of a feeder layer, serum, leukemia inhibitory factor (LIF) or BMP4 [18]. The mechanism of action was found to be independent of known self-renewal pathways thought to be essential (BMP4/Smad-Id [19], Wnt/B-catenin [20], LIF/STAT3 [21]).…”

Embryonic stem cell application in drug discovery

“…An outstanding landmark in the past decade has been the development between stem cell biology and chemistry [1][2][3][4][5][6] . The combination of the two fields will likely provide an impetus for revealing intricate molecular interactions and functions under complex cellular differentiation, which offers systems for drug discovery and sources for potential cell therapy [7][8][9][10] .…”