MicroRNA-302/367 cluster governs hESC self-renewal by dually regulating cell cycle and apoptosis pathways.
Bottom Line: We demonstrate that in addition to its role in cell cycle regulation, miR-302/367 cluster conquers apoptosis by downregulating BNIP3L/Nix (a BH3-only proapoptotic factor) and upregulating BCL-xL expression.Furthermore, we show that butyrate, a natural compound, upregulates miR-302/367 cluster expression and alleviates hESCs from apoptosis induced by knockdown of miR-302/367 cluster.In summary, our findings provide new insights in molecular mechanisms of how miR-302/367 cluster regulates hESCs.
Affiliation: Department of Medicine and Cancer Center, Division of Hematology/Oncology, University of Illinois at Chicago, Chicago, IL 60612, USA; Children's Hospital Oakland Research Institute, Oakland, CA 94609, USA; Berkeley Stem Cell Center, University of California at Berkeley, Berkeley, CA 94720, USA.Show MeSH
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Mentions: Because transforming growth factor-β1 (TGF-β1) is involved in apoptotic pathways in several types of cells (Lee and Bae, 2002; Schuster and Krieglstein, 2002), we thus asked whether miR-302/367 cluster regulates apoptosis via TGF-β1 signaling. To address this question, we treated two groups of hESCs (control-KRAB versus TALE1-KRAB) with or without TGF-β1 or SB431542 (a chemical inhibitor of TGF-β1 receptor). Our data showed that TGF-β1 or SB431542 had little effect on apoptosis in hESCs expressing TALE1-KRAB or control-KRAB (Figure S2). To dissect the molecular mechanisms by which miR-302/367 cluster dually regulates cell cycle and apoptosis in hESCs, we examined the expression of 21 cell cycle regulators by qPCR and found that knockdown of the endogenous miR-302/367 cluster by TALE1-KRAB inhibits the expression of BMI-1, CDK2, CCND1, CCND2, CDK6 (Figure 4A; Table S1). It has been shown that these molecules play important roles in regulation of G0/G1- to S-phase transition (Abdelalim, 2013). Thus, it is likely that the endogenous miR-302/367 cluster controls hESC cell cycle progression through the regulation of these key cell cycle regulators.
Affiliation: Department of Medicine and Cancer Center, Division of Hematology/Oncology, University of Illinois at Chicago, Chicago, IL 60612, USA; Children's Hospital Oakland Research Institute, Oakland, CA 94609, USA; Berkeley Stem Cell Center, University of California at Berkeley, Berkeley, CA 94720, USA.