scholarly journals A Key Role for Telomerase Reverse Transcriptase Unit in Modulating Human Embryonic Stem Cell Proliferation, Cell Cycle Dynamics, and In Vitro Differentiation

Stem Cells ◽  
2008 ◽  
Vol 26 (4) ◽  
pp. 850-863 ◽  
Author(s):  
Chunbo Yang ◽  
Stefan Przyborski ◽  
Michael J. Cooke ◽  
Xin Zhang ◽  
Rebecca Stewart ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Stem Cell ◽  
Human Embryonic Stem Cell ◽  
Embryonic Stem ◽  
Telomerase Reverse Transcriptase ◽  
In Vitro Differentiation ◽  
Stem Cell Proliferation ◽  
Cell Cycle Dynamics

Assessment of the ultrastructural and proliferative properties of human embryonic stem cell-derived cardiomyocytes

2003 ◽  
Vol 285 (6) ◽  
pp. H2355-H2363 ◽  
Author(s):  
Mirit Snir ◽  
Izhak Kehat ◽  
Amira Gepstein ◽  
Raymond Coleman ◽  
Joseph Itskovitz-Eldor ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Stem Cell ◽  
Embryonic Stem Cell ◽  
Late Stage ◽  
Human Embryonic Stem Cell ◽  
Embryonic Stem ◽  
Es Cell ◽  
Cardiomyocyte Proliferation ◽  
Ki 67

Assessment of early ultrastructural development and cell-cycle regulation in human cardiac tissue is significantly hampered by the lack of a suitable in vitro model. Here we describe the possible utilization of human embryonic stem cell (ES) lines for investigation of these processes. With the use of the embryoid body (EB) differentiation system, human ES cell-derived cardiomyocytes at different developmental stages were isolated and their histomorphometric, ultrastructural, and proliferative properties were characterized. Histomorphometric analysis revealed an increase in cell length, area, and length-to-width ratio in late-stage EBs (>35 days) compared with early (10–21 days) and intermediate (21–35 days) stages. This was coupled with a progressive ultrastructural development from an irregular myofibrillar distribution to an organized sarcomeric pattern. Cardiomyocyte proliferation, assessed by double labeling with cardiac-specific antibodies and either [3H]thymidine incorporation or Ki-67 immunolabeling, demonstrated a gradual withdrawal from cell cycle. Hence, the percentage of positively stained nuclei in early-stage cardiomyocytes ([3H]thymidine: 60 ± 10%, Ki-67: 54 ± 23%) decreased to 36 ± 7% and 9 ± 16% in intermediate-stage EBs and to <1% in late-stage cardiomyocytes. In conclusion, a reproducible temporal pattern of early cardiomyocyte proliferation, cell-cycle withdrawal, and ultrastructural maturation was noted in this model. Establishment of this unique in vitro surrogate system may allow to examine the molecular mechanisms underlying these processes and to assess interventions aiming to modify these properties. Moreover, the detailed characterization of the ES cell-derived cardiomyocyte may be crucial for the development of future cell replacement strategies aiming to regenerate functional myocardium.

scholarly journals The C-terminal Pentapeptide of Nanog Tryptophan Repeat Domain Interacts with Nac1 and Regulates Stem Cell Proliferation but Not Pluripotency

2009 ◽  
Vol 284 (24) ◽  
pp. 16071-16081 ◽  
Author(s):  
Tianhua Ma ◽  
Zhe Wang ◽  
Yunqian Guo ◽  
Duanqing Pei
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Stem Cell ◽  
Es Cells ◽  
Embryonic Stem ◽  
Akt Pathway ◽  
Wild Type ◽  
Phosphatidylinositol 3 Kinase ◽  
Stem Cell Proliferation ◽  
Phosphatidylinositol 3

Overexpression of Nanog in mouse embryonic stem (ES) cells has been shown to abrogate the requirement of leukemia inhibitory factor for self-renewal in culture. Little is known about the molecular mechanism of Nanog function. Here we describe the role of the tryptophan repeat (WR) domain, one of the two transactivators at its C terminus, in regulating stem cell proliferation as well as pluripotency. We first created a supertransactivator, W2W3×10, by duplicating repeats W2W3 10 times and discovered that it can functionally substitute for wild type WR at sustaining pluripotency, albeit with a significantly slower cell cycle, phenocopying Nanog(9W) with the C-terminal pentapeptide (WNAAP) of WR deleted. ES cells carrying both W2W3×10 and Nanog(9W) have a longer G1 phase, a shorter S phase in cell cycle distribution and progression analysis, and a lower level of pAkt(Ser473) compared with wild type Nanog, suggesting that both mutants impact the cell cycle machinery via the phosphatidylinositol 3-kinase/Akt pathway. Both mutants remain competent in dimerizing with Nanog but cannot form a complex with Nac1 efficiently, suggesting that WNAAP may be involved in Nac1 binding. By tagging Gal4DBD with WNAAP, we demonstrated that this pentapeptide is sufficient to confer Nac1 binding. Furthermore, we can rescue W2W3×10 by placing WNAAP at the corresponding locations. Finally, we found that Nanog and Nac1 synergistically up-regulate ERas expression and promote the proliferation of ES cells. These results suggest that Nanog interacts with Nac1 through WNAAP to regulate the cell cycle of ES cells via the ERas/phosphatidylinositol 3-kinase/Akt pathway, but not pluripotency, thus decoupling cell cycle control from pluripotency.

scholarly journals Loss of ZC4H2 and RNF220 Inhibits Neural Stem Cell Proliferation and Promotes Neuronal Differentiation

Cells ◽  
2020 ◽  
Vol 9 (7) ◽  
pp. 1600
Author(s):  
Longlong Zhang ◽  
Maosen Ye ◽  
Liang Zhu ◽  
Jingmei Cha ◽  
Chaocui Li ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Proliferation ◽  
Stem Cell ◽  
Neural Stem Cell ◽  
Stem Cell Proliferation ◽  
Neural Stem Cell Proliferation ◽  
Protein Levels ◽  
Ubiquitin E3 Ligase ◽  
Proliferation And Differentiation

The ubiquitin E3 ligase RNF220 and its co-factor ZC4H2 are required for multiple neural developmental processes through different targets, including spinal cord patterning and the development of the cerebellum and the locus coeruleus. Here, we explored the effects of loss of ZC4H2 and RNF220 on the proliferation and differentiation of neural stem cells (NSCs) derived from mouse embryonic cortex. We showed that loss of either ZC4H2 or RNF220 inhibits the proliferation and promotes the differentiation abilities of NSCs in vitro. RNA-Seq profiling revealed 132 and 433 differentially expressed genes in the ZC4H2−/− and RNF220−/− NSCs, compared to wild type (WT) NSCs, respectively. Specifically, Cend1, a key regulator of cell cycle exit and differentiation of neuronal precursors, was found to be upregulated in both ZC4H2−/− and RNF220−/− NSCs at the mRNA and protein levels. The targets of Cend1, such as CyclinD1, Notch1 and Hes1, were downregulated both in ZC4H2−/− and RNF220−/− NSCs, whereas p53 and p21 were elevated. ZC4H2−/− and RNF220−/− NSCs showed G0/G1 phase arrest compared to WT NSCs in cell cycle analysis. These results suggested that ZC4H2 and RNF220 are likely involved in the regulation of neural stem cell proliferation and differentiation through Cend1.

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