scholarly journals Proliferation maintains the undifferentiated status of stem cells: the role of the planarian cell cycle regulator Cdh1

2021 ◽  
Author(s):  
Yuki Sato ◽  
Yoshihiko Umesono ◽  
Yoshihito Kuroki ◽  
Kiyokazu Agata ◽  
Chikara Hashimoto
Keyword(s):  
Cell Cycle ◽  
Stem Cells ◽  
Cell Cycle Arrest ◽  
Cell Cycle Regulation ◽  
Body Parts ◽  
Differentiated Cells ◽  
Cycle Arrest ◽  
Dugesia Japonica ◽  
Signaling Activation ◽  
Cycle Regulation

The coincidence of cell cycle arrest and differentiation has been described in a wide variety of stem cells and organisms for decades, but the causal relationship is still unclear due to the complicated regulation of the cell cycle. Here, we used the planarian Dugesia japonica since it possesses a quite simple cell cycle regulation in which cdh1 is the only factor that arrests the cell cycle. When cdh1 was functionally inhibited, the planarians could not maintain their tissue homeostasis and could not regenerate their missing body parts. While the ablation of cdh1 caused pronounced propagation of the stem cells, the progenitor and differentiated cells were decreased. Further analysis indicated that the stem cells without cdh1 expression did not undergo differentiation even though they received ERK signaling activation as an induction signal. These results suggested that stem cells could not acquire differentiation competence without cell cycle arrest. Thus, we propose that cell cycle regulation determines the differentiation competence and that cell cycle exit to G0 enables stem cells to undergo differentiation.

Expression profiles of miRNAs and involvement of miR-100 and miR-34 in regulation of cell cycle arrest in Artemia

2015 ◽  
Vol 470 (2) ◽  
pp. 223-231 ◽  
Author(s):  
Ling-Ling Zhao ◽  
Feng Jin ◽  
Xiang Ye ◽  
Lin Zhu ◽  
Jin-Shu Yang ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Cell Cycle Regulation ◽  
Cell Cycle Progression ◽  
Expression Profiles ◽  
Regulatory Mechanisms ◽  
Cycle Progression ◽  
Cycle Arrest ◽  
Regulation Of Cell Cycle ◽  
Cycle Regulation

We established an expression profile of miRNA for cell cycle arrest in Artemia and found that miR-100 and miR-34 promote and prevent cell cycle progression respectively. The regulatory mechanisms of these two miRNAs provide insights into cell cycle regulation.

scholarly journals Inducing controlled cell cycle arrest and re-entry during asexual proliferation ofPlasmodium falciparummalaria parasites

2018 ◽  
Author(s):  
Riëtte van Biljon ◽  
Jandeli Niemand ◽  
Roelof van Wyk ◽  
Katherine Clark ◽  
Bianca Verlinden ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Cell Cycle Regulation ◽  
Malaria Parasites ◽  
New Approach ◽  
Mitotic Kinases ◽  
Cycle Arrest ◽  
Cycle Regulation ◽  
Early Phases

ABSTRACTThe life cycle of the malaria parasitePlasmodium falciparumis tightly regulated, oscillating between stages of intense proliferation and quiescence. Cyclic 48-hour asexual replication ofPlasmodiumis markedly different from cell division in higher eukaryotes, and mechanistically poorly understood. Here, we report tight synchronisation of malaria parasites during the early phases of the cell cycle by exposure to DL-α-difluoromethylornithine (DFMO), which results in the depletion of polyamines. This induces an inescapable cell cycle arrest in G1(~15 hours post-invasion) by blocking G1/S transition. Cell cycle-arrested parasites enter a quiescent G0-like state but, upon addition of exogenous polyamines, re-initiate their cell cycle in a coordinated fashion. This ability to halt malaria parasites at a specific point in their cell cycle, and to subsequently trigger re-entry into the cell cycle, provides a valuable framework to investigate cell cycle regulation in these parasites. We therefore used gene expression analyses to show that re-entry into the cell cycle involves expression of Ca2+-sensitive (cdpk4andpk2)and mitotic kinases (nimaandark2),with deregulation of the pre-replicative complex associated with expression ofpk2. Changes in gene expression could be driven through transcription factors MYB1 and two ApiAP2 family members. This new approach to parasite synchronisation therefore expands our currently limited toolkit to investigate cell cycle regulation in malaria parasites.

scholarly journals Characterization and Cell Cycle Regulation of the Major Kaposi’s Sarcoma-Associated Herpesvirus (Human Herpesvirus 8) Latent Genes and Their Promoter

1999 ◽  
Vol 73 (2) ◽  
pp. 1438-1446 ◽  
Author(s):  
Ronit Sarid ◽  
Jeffrey S. Wiezorek ◽  
Patrick S. Moore ◽  
Yuan Chang
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Cell Cycle Regulation ◽  
Kaposi's Sarcoma ◽  
Kaposi’S Sarcoma ◽  
Mrna Levels ◽  
Cycle Arrest ◽  
Kaposi's Sarcoma Associated Herpesvirus ◽  
Kaposi’S Sarcoma Associated Herpesvirus ◽  
Cycle Regulation

ABSTRACT Retinoblastoma tumor suppressor protein (pRB) inhibition by tumor virus oncoproteins has been attributed to the need for these viruses to promote lytic viral nucleic acid synthesis by unscheduled entry into the S phase of the cell cycle. Kaposi’s sarcoma-associated herpesvirus (KSHV or HHV8) encodes a functional cyclin (vCYC) which is expressed during latency and can direct phosphorylation of pRB. We mapped the two major latent transcripts encoding vCYC, latent transcript 1 (LT1) and LT2, by cDNA sequencing, 5′ rapid amplification of cDNA ends, and primer extension analyses. Both LT1 and LT2 transcripts are spliced, originate from the same start site, and encode ORF K13 (vFLIP) as well as ORF72 (vCYC). The latency-associated nuclear antigen (LANA, ORF73) is encoded by LT1 but spliced from LT2. While differential expression of the two transcripts was not found, the promoter controlling LT1/LT2 transcription is regulated in a cell cycle-dependent manner. Activities of both KSHV LT1/LT2 and huCYC D1 luciferase promoter reporters transfected into NIH 3T3 cells increase 11- and 4-fold, respectively, after release from cell cycle arrest by serum starvation. Further, vCYC and huCYC D2 mRNA levels are low in naturally infected BCBL-1 cells arrested in late G1 with l-mimosine but increase in parallel during a 24-h period after release from cell cycle arrest. Cell cycle regulation of KSHV vCYC expression mimics cellular D cyclin regulation and may maintain infected cell cycling. This is consistent with an alternative hypothesis that tumor viruses have developed specific responses to innate cellular defenses against latent virus infection that include pRB-induced cell cycle arrest.

scholarly journals Inhibition of TFII-I-Dependent Cell Cycle Regulation by p53

2005 ◽  
Vol 25 (24) ◽  
pp. 10940-10952 ◽  
Author(s):  
Zana P. Desgranges ◽  
Jinwoo Ahn ◽  
Maria B. Lazebnik ◽  
Todd Ashworth ◽  
Caleb Lee ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cyclin D1 ◽  
Cell Cycle Arrest ◽  
Cell Cycle Regulation ◽  
Cellular Proliferation ◽  
Cell Cycle Control ◽  
Genotoxic Stress ◽  
Dependent Manner ◽  
Cycle Arrest ◽  
Cycle Regulation

ABSTRACT The multifunctional transcription factor TFII-I is tyrosine phosphorylated in response to extracellular growth signals and transcriptionally activates growth-promoting genes. However, whether activation of TFII-I also directly affects the cell cycle profile is unknown. Here we show that under normal growth conditions, TFII-I is recruited to the cyclin D1 promoter and transcriptionally activates this gene. Most strikingly, upon cell cycle arrest resulting from genotoxic stress and p53 activation, TFII-I is ubiquitinated and targeted for proteasomal degradation in a p53- and ATM (ataxia telangiectasia mutated)-dependent manner. Consistent with a direct role of TFII-I in cell cycle regulation and cellular proliferation, stable and ectopic expression of wild-type TFII-I increases cyclin D1 levels, resulting in accelerated entry to and exit from S phase, and overcomes p53-mediated cell cycle arrest, despite radiation. We further show that the transcriptional regulation of cyclin D1 and cell cycle control by TFII-I are dependent on its tyrosine phosphorylation at positions 248 and 611, sites required for its growth signal-mediated transcriptional activity. Taken together, our data define TFII-I as a growth signal-dependent transcriptional activator that is critical for cell cycle control and proliferation and further reveal that genotoxic stress-induced degradation of TFII-I results in cell cycle arrest.

scholarly journals PAWI-2 overcomes tumor stemness and drug resistance via cell cycle arrest in integrin β3-KRAS-dependent pancreatic cancer stem cells

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Jiongjia Cheng ◽  
John R. Cashman
Keyword(s):  
Cell Cycle ◽  
Pancreatic Cancer ◽  
Stem Cells ◽  
Cancer Stem Cells ◽  
Cell Cycle Arrest ◽  
Specific Inhibitor ◽  
Feedback Mechanism ◽  
Major Health Problem ◽  
Cycle Arrest ◽  
Drug Inhibition

Abstract Today, pancreatic cancer (PC) remains a major health problem in the US. The fact that cancer stem cells (CSCs) become enriched in humans following anti-cancer therapy implicates CSCs as key contributors to tumor dormancy, metastasis, and relapse in PC. A highly validated CSC model (FGβ3 cells) was used to test a novel compound (PAWI-2) to eradicate CSCs. Compared to parental bulk FG cells, PAWI-2 showed greater potency to inhibit cell viability and self-renewal capacity of FGβ3 cells. For FGβ3 cells, dysregulated integrin β3-KRAS signaling drives tumor progression. PAWI-2 inhibited β3-KRAS signaling independent of KRAS. This is clinically relevant. PAWI-2 targeted the downstream TBK1 phosphorylation cascade that was negatively regulated by optineurin phosphorylation via a feedback mechanism. This was confirmed by TBK1 genetic knockdown or co-treatment with TBK1-specific inhibitor (MRT67307). PAWI-2 also overcame erlotinib (an EGFR inhibitor) resistance in FGβ3 cells more potently than bortezomib. In the proposed working model, optineurin acts as a key regulator to link inhibition of KRAS signaling and cell cycle arrest (G2/M). The findings show PAWI-2 is a new approach to reverse tumor stemness that resensitizes CSC tumors to drug inhibition.

Abstract W P198: Sphingomyelin Synthases Regulate Neuronal Cell Proliferation and Cell Cycle Progression

Stroke ◽  
2014 ◽  
Vol 45 (suppl_1) ◽  
Author(s):  
Umadevi V Wesley ◽  
Daniel Tremmel ◽  
Robert Dempsey
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Regulation ◽  
Cell Cycle Progression ◽  
Molecular Mechanisms ◽  
Neuronal Cell ◽  
Artery Occlusion ◽  
Cycle Progression ◽  
Cycle Arrest ◽  
Cycle Regulation ◽  
Cerebral Artery Occlusion

Introduction: The molecular mechanisms of cerebral ischemia damage and protection are not completely understood, but a number of reports implicate the contribution of lipid metabolism and cell-cycle regulating proteins in stroke out come. We have previously shown that tricyclodecan-9-yl-xanthogenate (D609) resulted in increased ceramide levels after transient middle cerebral artery occlusion (tMCAO) in spontaneously hypertensive rat (SHR). We hypothesized that D609 induced cell cycle arrest probably by inhibiting sphingomyelin synthase (SMS). In this study, we examined the direct effects of SMS on cell cycle progression and proliferation of neuroblast cells. Methods: Ischemia was induced by middle cerebral artery occlusion (MCAO) and reperfusion. Expression levels were measured by western blot analysis, RT-PCR, and Immunofluorescence staining. SMS1 and 2 expressions were silenced by stable transfection with SMS1/2-targeted shRNA. Cell cycle analysis was performed using Flow cytometry. Data were analyzed using MODFIT cell cycle analysis program. Cell proliferation rate was measured by MTT assay. Results: We have identified that the expression of SMS1is significantly up-regulated in the ischemic hemisphere following MCAO. Neuro-2a cells transfected with SMS specific ShRNA acquired more neuronal like phenotype and exhibited decreased proliferation rate. Also, silencing of both SMS1 and 2 induced cell-cycle arrest as shown by significantly increased percentage of cells in G0/G1 and decreased proportion of cells in S-phase as compared to control cells. This was accompanied by up-regulation of cyclin-dependent kinase (Cdk) inhibitors p21 and decreased levels of phophorylated AKT levels. Furthermore, loss of SMS inhibited the migratory potential of Neuro 2a cells. Summary: Up-regulation of SMS under ischemic/reperfusion conditions suggests that this enzyme potentially contributes to cell cycle regulation and may contribute to maintaining neuronal cell population. Further studies may open up a new direction for identifying the molecular mechanisms of cell cycle regulation and protection following ischemic stroke

scholarly journals Increased proliferation and altered cell cycle regulation in pancreatic stem cells derived from patients with congenital hyperinsulinism

PLoS ONE ◽  
2019 ◽  
Vol 14 (9) ◽  
pp. e0222350 ◽  
Author(s):  
Sophie G. Kellaway ◽  
Karolina Mosinska ◽  
Zainaba Mohamed ◽  
Alexander Ryan ◽  
Stephen Richardson ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Stem Cells ◽  
Cell Cycle Regulation ◽  
Congenital Hyperinsulinism ◽  
Pancreatic Stem Cells ◽  
Altered Cell ◽  
Cycle Regulation

scholarly journals Babam2 Regulates Cell Cycle Progression and Pluripotency in Mouse Embryonic Stem Cells as Revealed by Induced DNA Damage

Biomedicines ◽  
2020 ◽  
Vol 8 (10) ◽  
pp. 397
Author(s):  
Cheuk Yiu Tenny Chung ◽  
Paulisally Hau Yi Lo ◽  
Kenneth Ka Ho Lee
Keyword(s):  
Cell Cycle ◽  
Stem Cells ◽  
Dna Damage ◽  
Gamma Irradiation ◽  
Cellular Senescence ◽  
Cell Cycle Regulation ◽  
Cell Cycle Progression ◽  
Embryonic Stem ◽  
Cycle Progression ◽  
Cycle Regulation

BRISC and BRCA1-A complex member 2 (Babam2) plays an essential role in promoting cell cycle progression and preventing cellular senescence. Babam2-deficient fibroblasts show proliferation defect and premature senescence compared with their wild-type (WT) counterpart. Pluripotent mouse embryonic stem cells (mESCs) are known to have unlimited cell proliferation and self-renewal capability without entering cellular senescence. Therefore, studying the role of Babam2 in ESCs would enable us to understand the mechanism of Babam2 in cellular aging, cell cycle regulation, and pluripotency in ESCs. For this study, we generated Babam2 knockout (Babam2−/−) mESCs to investigate the function of Babam2 in mESCs. We demonstrated that the loss of Babam2 in mESCs leads to abnormal G1 phase retention in response to DNA damage induced by gamma irradiation or doxorubicin treatments. Key cell cycle regulators, CDC25A and CDK2, were found to be degraded in Babam2−/− mESCs following gamma irradiation. In addition, Babam2−/− mESCs expressed p53 strongly and significantly longer than in control mESCs, where p53 inhibited Nanog expression and G1/S cell cycle progression. The combined effects significantly reduced developmental pluripotency in Babam2−/− mESCs. In summary, Babam2 maintains cell cycle regulation and pluripotency in mESCs in response to induced DNA damage.

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