BMP4 preserves the developmental potential of mESCs through Ube2s- and Chmp4b-mediated chromosomal stability safeguarding

Mingzhu Wang,Jiqing Yin,Hong Wang,Yanhong Zhao,Xiaochen Kou,Zhibin Qiao,Jiayu Chen,Yonghua Jiang,Shaorong Gao,Mengting Wang,Meng Liu,Cizhong Jiang,Kun Zhao,Tianming Li,Shanru Yi

doi:10.1007/s13238-021-00896-x

Abstract

Chemically defined medium is widely used for culturing mouse embryonic stem cells (mESCs), in which N2B27 works as a substitution for serum, and GSK3β and MEK inhibitors (2i) help to promote ground-state pluripotency. However, recent studies suggested that MEKi might cause irreversible defects that compromise the developmental potential of mESCs. Here, we demonstrated the deficient bone morphogenetic protein (BMP) signal in the chemically defined condition is one of the main causes for the impaired pluripotency. Mechanistically, activating the BMP signal pathway by BMP4 could safeguard the chromosomal integrity and proliferation capacity of mESCs through regulating downstream targets Ube2s and Chmp4b. More importantly, BMP4 promotes a distinct in vivo developmental potential and a long-term pluripotency preservation. Besides, the pluripotent improvements driven by BMP4 are superior to those by attenuating MEK suppression. Taken together, our study shows appropriate activation of BMP signal is essential for regulating functional pluripotency and reveals that BMP4 should be applied in the serum-free culture system.

Highlights

Mouse embryonic stem cells are derived from the inner cell mass (ICM) of the developing blastocyst and have the abilities of self-renewal and pluripotency to reconstitute embryonic lineages (Evans and Kaufman, 1981; Martin, 1981)
Our study reveals that bone morphogenetic protein 4 (BMP4) needs to be applied to maintain the chromosomal integrity and to remold in vivo differentiation potency of Mouse embryonic stem cells (mESCs) cultured in the serum-free system
Addition of BMP4 in N/2i condition can restore the expression of ubiquitin-conjugating enzyme E2S (Ube2s) and charged multivesicular body protein 4B (Chmp4b), which further safeguards chromosomal integrity and largely promotes in vivo differentiation potential of mESCs

Summary

Introduction

Mouse embryonic stem cells (mESCs) are derived from the inner cell mass (ICM) of the developing blastocyst and have the abilities of self-renewal and pluripotency to reconstitute embryonic lineages (Evans and Kaufman, 1981; Martin, 1981). It has been reported that culture conditions could greatly affect genome stability, transcriptome, epigenome, proliferation and differentiation capacity of mESCs (Ying et al, 2003; Habibi et al, 2013; Hassani et al, 2014; Kolodziejczyk et al, 2015; Ter Huurne et al, 2017; Lee et al, 2018). FBS is considered important because it provides certain critical biological molecules such as albumin, apolipoproteins and biotin (Halliwell, 1988; Zheng et al, 2006; Uddin et al, 2020) and growthsupporting factors such as bone morphogenetic protein 4 (BMP4), which stimulates downstream SMAD signaling pathways to activate inhibitor of differentiation (Id) genes (Baker et al, 1988; Ying et al, 2003). It has been demonstrated that mESCs cultured in the S condition are in a metastable status and exhibit volatile transcriptional and epigenetic profiles and, functional heterogeneity among cells (Hayashi et al, 2008; Hackett and Surani, 2014)

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Conclusion