Augmented BMP۴ Signaling Plays A Critical Role in Self-renewal of Mouse Embryonic Stem Cells

Efficient control of the self-renewal and pluripotency maintenanceof embryonic stem cell (ESC) is a prerequisite for translatingstem cell technologies to clinical applications. ۲i and R۲iculture conditions are considered to maintain the pluripotencyof mouse embryonic stem cells. In this study, we investigatedthe cell signaling and mechanism of the cells grown under ۲iand R۲i conditions. Previous high-throughput analysis indicatedthat BMP-related signaling mediators were upregulated inR۲i versus ۲i. To clarify the role of this pathway under pluripotentstate, using functional pathway analysis we showed that theR۲i cells were adversely affected and dead after treatment withBMP۴ signaling inhibitors (Noggin and Dorsomorphin), whilethe proliferation and expression of pluripotency marker genesin ۸۰% of ۲i-grown cells decreased and the rest of the populationshowed resistance to this treatment. By the knockdown ofdownstream target genes (Smad۱,۵,۸, Id۱ and Id۲) we showedthat the inhibition of canonical pathway of BMP۴ signaling hasno effect on the survival of the cells, while inhibition of JNK asa target of non-canonical pathway of BMP caused a significantdecrease in both of ۲i- and R۲i-grown cells. About ۲۰% of ۲iculturedcells showed resistance and survived against BMPi.We speculated that ۲i is a heterogeneous population. To provethis hypothesis, ۲i cells were cultured under BMPi up to fivepassages, to sorted resistance population in the presence of inhibitorswhich are known as ۲i-sorted BMPi. We showed that۲i-sorted BMPi not only are pluripotent population, but also incomparison with ۲i shows a higher potential in the expressionof pluripotency marker genes. In conclusion, we revealed thatinhibition of BMP۴ signaling pathways, leading to death inR۲i- and part of ۲i-grown cells. By this treatment we could sorta pluripotent population of ۲i which showed resistance againstBMPi.

کلیدواژه ها:

Mouse Embryonic Stem Cell ، Pluripotency ، ۲i ، R۲i ، BMP۴ Signaling Pathway