Project description:The self-renewing pluripotent state was first captured in mouse embryonic stem cells (mESCs) over two decades ago. The standard condition requires the presence of serum and LIF, which provide growth promoting signals for cell expansion. However, there are pro-differentiation signals which destabilize the undifferentiated state of mESCs. The dual inhibition (2i) of the pro-differentiation Mek/Erk and Gsk3/Tcf3 pathways in mESCs is sufficient to establish an enhanced pluripotent “ground state” which bears features resembling the pre-implantation mouse epiblast. Gsk3 inhibition alleviates the repression of Esrrb, a transcription factor that can substitute for Nanog function in mESCs. The molecular mechanism that is mediated by Mek inhibition is however not clear. In this study, we investigate the pathway through which Mek inhibition operates to maintain ground state pluripotency. We have found that in mESCs, Kruppel-like factor 2 (Klf2) is a protein target of the Mek/Erk pathway; and that Klf2 protein is phosphorylated by Erk2 and subsequently degraded through the proteosome. It is therefore by Mek-inhibition through PD0325901 or 2i that enables the stabilization and accumulation of Klf2 to sustain ground state pluripotency. Importantly, we found that Klf2-null mESCs, while viable under LIF/Serum conditions, cannot be maintained and eventually gradually die within a few passages. Our result thus demonstrates that Klf2 is an essential factor of ground state pluripotency. Collectively, our study defines the Mek/Klf2 axis that cooperates with the Gsk3/Esrrb pathway in mediating ground state pluripotency.
Project description:Kanate was used to induce seizures in mice, and gene expression in the hippocampus was measured Using MEK inhibitors, MEK-dependent gene expression was assessed.
Project description:The most common oncogenic mutations in multiple myeloma (MM) affect N- and K-RAS leading to constitutive activation of RAS-dependent signaling. Signal transduction via RAS, Raf and MAPK has been well described as a canonical pathway. In accordance with this assumption, we showed that the activity of the MEK/ERK module is strictly dependent on pan-Raf activity. However, inhibition of MEK/ERK has no or only minor effects on MM cell survival, whereas oncogenic Ras and pan-Raf critically contribute to survival of multiple myeloma cells. Therefore, we aimed to learn more about Raf-dependent but MEK-independent signaling effectors. We analyzed gene expression profiles in INA-6 cells after either pan-Raf inhibition with SB-590885 or MEK inhibition with PD-325901.
Project description:Gene Expression dynamics is important information. To know IKK- or ERK-dependent B cell receptor- or CD40-induced gene expression dynamics, we performed the time course and dose response analysis in wild type or MEK inhibitor treated or IKKbeta inactive DT40 B cells. Two replicated samples were analysed. Unstimulated cells (T0) were control. WT cells or MEK Inh. (MEK inhibitor;U0126 5mM, 30min pretreated) or IKKbetaSA (S176/181A knock-in) Cells were stimulated with 0.1, 1, 10 µg/ml of anti-IgM (M4) or 1, 3, 6 µg/ml of CD40ligand (CD40L) for 0, 15, 30, 45, 60 or 90min.
Project description:Gene Expression dynamics is important information. To know IKK- or ERK-dependent B cell receptor- or CD40-induced gene expression dynamics, we performed the time course and dose response analysis in wild type or MEK inhibitor treated or IKKbeta inactive DT40 B cells.
