Notch induces cyclin-D1-dependent proliferation during a specific temporal window of neural differentiation in ES cells

Abstract

The Notch signaling pathway controls cell fate choices at multiple steps during cell lineage progression. To produce the cell fate choice appropriate for a particular stage in the cell lineage, Notch signaling needs to interpret the cell context information for each stage and convert it into the appropriate cell fate instruction. The molecular basis for this temporal context-dependent Notch signaling output is poorly understood, and to study this, we have engineered a mouse embryonic stem (ES) cell line, in which short pulses of activated Notch can be produced at different stages of in vitro neural differentiation. Activation of Notch signaling for 6h specifically at day 3 during neural induction in the ES cells led to significantly enhanced cell proliferation, accompanied by Notch-mediated activation of cyclin D1 expression. A reduction of cyclin-D1-expressing cells in the developing CNS of Notch signaling-deficient mouse embryos was also observed. Expression of a dominant negative form of cyclin D1 in the ES cells abrogated the Notch-induced proliferative response, and, conversely, a constitutively active form of cyclin D1 mimicked the effect of Notch on cell proliferation. In conclusion, the data define a novel temporal context-dependent function of Notch and a critical role for cyclin D1 in the Notch-induced proliferation in ES cells.

NOTCH activation interferes with cell fate specification in the gastrulating mouse embryo

“…This observation is consistent with the results from in vitro studies showing that NOTCH activation enhances and accelerates neural specification in mESCs and hESCs upon withdrawal of self-renewing stimuli (Lowell et al, 2006). In ESCs, NOTCH coordinates the response to neural inductive cues such as FGF, protects the cells against non-neural fates and stimulates proliferation of neural precursors in a cyclin D-dependent manner (Das et al, 2010;Lowell et al, 2006). In addition, in vivo studies have shown that Sox1 expression in the spinal cord depends on NOTCH signalling (Genethliou et al, 2009).…”

“…NOTCH activity is notably required to maintain a pool of neural progenitors and to inhibit further neural differentiation, but can also regulate the acquisition of distinct cell fates by promoting gliogenesis or influencing binary fate choices during neurogenesis (reviewed by Pierfelice et al, 2011;Yoon and Gaiano, 2005). A role for the NOTCH pathway during early neural specification has been pinpointed by gain-and loss-of-function in vitro analyses showing that NOTCH activity promotes neural lineage commitment in pluripotent ESCs (Das et al, 2010;Kurpinski et al, 2010;Lowell et al, 2006). In order to investigate whether the NOTCH pathway can also play such an early role during in vivo neural development, we analysed the formation of neurectodermal tissue in N1ICD epi embryos.…”

“…However, canonical NOTCH signalling has been shown to regulate lineage commitment when ESCs are induced to differentiate. Constitutive expression of NICD in mESCs or treatment of hESCs with DLL1-expressing feeders favours the acquisition of a neurectodermal fate (Das et al, 2010;Kurpinski et al, 2010;Lowell et al, 2006). By contrast, inactivation of the NOTCH pathway with a γ-SECRETASE inhibitor or via genetic deletion of Notch1 and Rbpj accelerates ESC differentiation towards mesoderm, and enhances their cardiogenic potential (Jang et al, 2008;Nemir et al, 2006;Schroeder et al, 2003).…”

Notch signaling: simplicity in design, versatility in function

“…Genome-wide transcriptome studies in healthy or mutated T-cells (Chadwick et al, 2009;Dohda et al, 2007;Palomero et al, 2006;Weerkamp et al, 2006), mouse embryonic stem (ES) cells (Main et al, 2010;Meier-Stiegen et al, 2010), alveolar epithelial cells (Aoyagi-Ikeda et al, 2011), endometrial stromal cells (Mikhailik et al, 2009), C2C12 mouse myoblast cells (Buas et al, 2009) and Drosophila myogenic cells (Krejci et al, 2009) have unraveled distinct sets of Notch target genes with rather limited overlap of the transcriptomes. This is the case even when comparing transcriptome studies that were carried out with relatively similar modes and durations of Notch induction (summarized in Fig.…”

The H+Vacuolar ATPase Maintains Neural Stem Cells in the Developing Mouse Cortex

“…Finally, it is interesting to note that membrane potential and cellular pH can influence cell cycle progression and differentiation [22,43] and that inhibition of Notch has been shown to lengthen the cell cycle, in particular G1, of neural precursors [48], which is probably due to its effects on cyclin D1 expression [49]. The fact that lengthening of G1 may alone cause the differentiation of neural [50], and likely also other [51], stem cells reveals an elegant interplay between the cell biophysical state, signaling molecules, cell cycle progression, and differentiation during animal development, which should be better explored in future studies.…”