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

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 Phosphorylation of RCC1 on Serine 11 Facilitates G1/S Transition in HPV E7-Expressing Cells

Biomolecules ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 995
Author(s):  
Xiaoyan Hou ◽  
Lijun Qiao ◽  
Ruijuan Liu ◽  
Xuechao Han ◽  
Weifang Zhang
Keyword(s):  
Cell Cycle ◽  
Cervical Cancer ◽  
Cell Cycle Regulation ◽  
Cell Cycle Progression ◽  
Mtor Pathway ◽  
Cycle Progression ◽  
Post Translational Modifications ◽  
Hpv E7 ◽  
Cycle Regulation

Persistent infection of high-risk human papillomavirus (HR-HPV) plays a causal role in cervical cancer. Regulator of chromosome condensation 1 (RCC1) is a critical cell cycle regulator, which undergoes a few post-translational modifications including phosphorylation. Here, we showed that serine 11 (S11) of RCC1 was phosphorylated in HPV E7-expressing cells. However, S11 phosphorylation was not up-regulated by CDK1 in E7-expressing cells; instead, the PI3K/AKT/mTOR pathway promoted S11 phosphorylation. Knockdown of AKT or inhibition of the PI3K/AKT/mTOR pathway down-regulated phosphorylation of RCC1 S11. Furthermore, S11 phosphorylation occurred throughout the cell cycle, and reached its peak during the mitosis phase. Our previous data proved that RCC1 was necessary for the G1/S cell cycle progression, and in the present study we showed that the RCC1 mutant, in which S11 was mutated to alanine (S11A) to mimic non-phosphorylation status, lost the ability to facilitate G1/S transition in E7-expressing cells. Moreover, RCC1 S11 was phosphorylated by the PI3K/AKT/mTOR pathway in HPV-positive cervical cancer SiHa and HeLa cells. We conclude that S11 of RCC1 is phosphorylated by the PI3K/AKT/mTOR pathway and phosphorylation of RCC1 S11 facilitates the abrogation of G1 checkpoint in HPV E7-expressing cells. In short, our study explores a new role of RCC1 S11 phosphorylation in cell cycle regulation.

Pyk2 and FAK differentially regulate progression of the cell cycle

2000 ◽  
Vol 113 (17) ◽  
pp. 3063-3072 ◽  
Author(s):  
J. Zhao ◽  
C. Zheng ◽  
J. Guan
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Regulation ◽  
Cell Cycle Progression ◽  
Expression System ◽  
Chimeric Protein ◽  
Kinase Domain ◽  
Cycle Progression ◽  
Erk Activation ◽  
Terminal Domain ◽  
Cycle Regulation

We have previously identified FAK and its associated signaling pathways as a mediator of cell cycle progression by integrins. In this report, we have analyzed the potential role and mechanism of Pyk2, a tyrosine kinase closely related to FAK, in cell cycle regulation by using tetracycline-regulated expression system as well as chimeric molecules. We have found that induction of Pyk2 inhibited G(1) to S phase transition whereas comparable induction of FAK expression accelerated it. Furthermore, expression of a chimeric protein containing Pyk2 N-terminal and kinase domain and FAK C-terminal domain (PFhy1) increased cell cycle progression as FAK. Conversely, the complementary chimeric molecule containing FAK N-terminal and kinase domain and Pyk2 C-terminal domain (FPhy2) inhibited cell cycle progression to an even greater extent than Pyk2. Biochemical analyses indicated that Pyk2 and FPhy2 stimulated JNK activation whereas FAK or PFhy1 had little effect on it, suggesting that differential activation of JNK by Pyk2 may contribute to its inhibition of cell cycle progression. In addition, Pyk2 and FPhy2 to a greater extent also inhibited Erk activation in cell adhesion whereas FAK and PFhy1 stimulated it, suggesting a role for Erk activation in mediating differential regulation of cell cycle by Pyk2 and FAK. A role for Erk and JNK pathways in mediating the cell cycle regulation by FAK and Pyk2 was also confirmed by using chemical inhibitors for these pathways. Finally, we showed that while FAK and PFhy1 were present in focal contacts, Pyk2 and FPhy2 were localized in the cytoplasm. Interestingly, both Pyk2 and FPhy2 (to a greater extent) were tyrosine phosphorylated and associated with Src and Fyn. This suggested that they may inhibit Erk activation in an analogous manner as the mislocalized FAK mutant (Δ)C14 described previously by competing with endogenous FAK for binding signaling molecules such as Src and Fyn. This model is further supported by an inhibition of endogenous FAK association with active Src by Pyk2 and FPhy2 and a partial rescue by FAK of Pyk2-mediated cell cycle inhibition.

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.

The direct and indirect effects of corticosterone and primary adipose tissue on MCF7 breast cancer cell cycle progression

2015 ◽  
Vol 22 (2) ◽  
Author(s):  
Yaniv Shpilberg ◽  
Michael K. Connor ◽  
Michael C. Riddell
Keyword(s):  
Breast Cancer ◽  
Cell Cycle ◽  
Adipose Tissue ◽  
Cancer Cell ◽  
Indirect Effects ◽  
Cell Cycle Regulation ◽  
Cell Cycle Progression ◽  
Direct And Indirect Effects ◽  
Cycle Progression ◽  
Cycle Regulation

AbstractBreast cancer is the second leading cause of cancer-related mortality in women. Glucocorticoids (GCs) have the potential to directly affect breast cancer or indirectly via changes to the tumor growth microenvironment a breast cancer is exposed to. The role of GCs in breast cancer progression by direct and indirect means are not fully understood.To study the direct and indirect effects of GCs on breast cancer cell cycle regulation.MCF7 breast cancer cells were incubated with increasing concentrations of corticosterone (CORT) to investigate the direct effects. In addition, MCF7 cells were cultured in conditioned media (CM) from primary adipose tissue excised from CORT-supplemented lean and obese male rats.CORT alone resulted in dose-dependent increases in p27 and hypophosphorylated retinoblastoma protein (Rb) which was accompanied by a reduction in the number of cells in S-phase. CM prepared from adipose tissue overrode these direct CORT effects, suggesting that the tumor growth microenvironment created in the CM dominates MCF7 cell cycle regulation.The direct inhibitory effects of CORT on cancer cell cycle progression are largely limited by the hormone’s effects on adipose tissue biology.

scholarly journals The N-Terminal 24 Amino Acids of the p55 Gamma Regulatory Subunit of Phosphoinositide 3-Kinase Binds Rb and Induces Cell Cycle Arrest

2003 ◽  
Vol 23 (5) ◽  
pp. 1717-1725 ◽  
Author(s):  
Xianmin Xia ◽  
Aiwu Cheng ◽  
Damilola Akinmade ◽  
Anne W. Hamburger
Keyword(s):  
Cell Cycle ◽  
Amino Acid ◽  
Cell Cycle Arrest ◽  
Cell Cycle Progression ◽  
Molecular Mechanisms ◽  
Biological Effects ◽  
Cycle Progression ◽  
Regulatory Subunits ◽  
Cycle Arrest ◽  
Phosphoinositide 3 Kinase

ABSTRACT Although phosphoinositide 3-kinase (PI 3-kinase) is essential for cell cycle progression, the molecular mechanisms that regulate its diverse biological effects are poorly understood. We demonstrate here that Rb, a key regulator of cell cycle progression, associates with p55 kDa (p55α and p55γ) regulatory subunits of PI 3-kinase in vivo and in vitro. Both confocal microscopy and biochemical analysis demonstrated the presence of p55γ in the nucleus. The 24-amino-acid N-terminal end of p55γ, which is unique among PI 3-kinase regulatory subunits, was sufficient to bind Rb. Addition of serum or growth factors to quiescent cells triggered the dissociation of Rb from p55. Ectopic expression of the 24-amino-acid N-terminal end of p55γ inhibited cell cycle progression, as evidenced by induction of cell growth arrest at the G0/G1 phase, inhibition of DNA synthesis, inhibition of cyclin D and cyclin E promoter activity, and changes in the expression of cell cycle-related proteins. The inhibitory effects of the N-terminal end of p55γ on cell cycle progression depended on the presence of functional Rb. These data demonstrate for the first time an association of p55γ with Rb and show that modification of this association can lead to cell cycle arrest.

scholarly journals A role for ATP Citrate Lyase in cell cycle regulation during myeloid differentiation

2019 ◽  
Author(s):  
Jess Rhee ◽  
Lauren A. Solomon ◽  
Rodney P. DeKoter
Keyword(s):  
Cell Cycle ◽  
Fatty Acid ◽  
Cell Cycle Regulation ◽  
Cell Cycle Progression ◽  
Acid Synthesis ◽  
Atp Citrate Lyase ◽  
Acetyl Coa ◽  
Cycle Arrest ◽  
Citrate Lyase ◽  
Cycle Regulation

AbstractDifferentiation of myeloid progenitor cells into macrophages is accompanied by increased PU.1 concentration and increasing cell cycle length, culminating in cell cycle arrest. Induction of PU.1 expression in a cultured myeloid cell line expressing low PU.1 concentration results in decreased levels of mRNA encoding ATP-Citrate Lyase (ACL) and cell cycle arrest. ACL is an essential enzyme for generating acetyl-CoA, a key metabolite for the first step in fatty acid synthesis as well as for histone acetylation. We hypothesized that ACL may play a role in cell cycle regulation in the myeloid lineage. In this study, we found that acetyl-CoA or acetate supplementation was sufficient to rescue cell cycle progression in cultured BN cells treated with an ACL inhibitor or induced for PU.1 expression. Acetyl-CoA supplementation was also sufficient to rescue cell cycle progression in BN cells treated with a fatty acid synthase (FASN) inhibitor. We demonstrated that acetyl-CoA was utilized in both fatty acid synthesis and histone acetylation pathways to promote proliferation. Finally, we found that Acly mRNA transcript levels decrease during normal macrophage differentiation from bone marrow precursors. Our results suggest that regulation of ACL activity is a potentially important point of control for cell cycle regulation in the myeloid lineage.

scholarly journals Tell the Difference Between Mitosis and Meiosis: Interplay Between Chromosomes, Cytoskeleton, and Cell Cycle Regulation

2021 ◽  
Vol 9 ◽  
Author(s):  
Masamitsu Sato ◽  
Yasutaka Kakui ◽  
Mika Toya
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Progression ◽  
Molecular Mechanisms ◽  
Cycle Progression ◽  
The Past ◽  
Recent Advancement ◽  
Specific Factors ◽  
The Difference ◽  
Cycle Regulation ◽  
Mitosis And Meiosis

Meiosis is a specialized style of cell division conserved in eukaryotes, particularly designed for the production of gametes. A huge number of studies to date have demonstrated how chromosomes behave and how meiotic events are controlled. Yeast substantially contributed to the understanding of the molecular mechanisms of meiosis in the past decades. Recently, evidence began to accumulate to draw a perspective landscape showing that chromosomes and microtubules are mutually influenced: microtubules regulate chromosomes, whereas chromosomes also regulate microtubule behaviors. Here we focus on lessons from recent advancement in genetical and cytological studies of the fission yeast Schizosaccharomyces pombe, revealing how chromosomes, cytoskeleton, and cell cycle progression are organized and particularly how these are differentiated in mitosis and meiosis. These studies illuminate that meiosis is strategically designed to fulfill two missions: faithful segregation of genetic materials and production of genetic diversity in descendants through elaboration by meiosis-specific factors in collaboration with general factors.

The MEIS1 Interactome in Megakaryocytes Reveals a Role in Cell Cycle Regulation,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3380-3380
Author(s):  
Vishal A Salunkhe ◽  
Iain Macaulay ◽  
Sylvia Nuernberg ◽  
Cathal McCarthy ◽  
Willem Hendrik Ouwehand ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Regulation ◽  
Cell Cycle Progression ◽  
Cyclin D3 ◽  
Haematopoietic Stem Cell ◽  
Nuclear Fraction ◽  
Cell Cycle Regulators ◽  
Cycle Progression ◽  
Cycle Regulation

Abstract Abstract 3380 Haematopoiesis is highly coordinated process of fate determination at branch points that is regulated by transcription factors and their cofactors. Our comprehensive catalogue of transcripts in the eight main mature blood cell elements, including erythroblasts and megakaryocytes (MKs) showed that the transcription factor MEIS1 is uniquely transcribed in MKs and the CD34+ haematopoietic stem cell. Gene silencing studies in mice and zebrafish has shown a pivotal role for MEIS1 in haematopoiesis, megakaryopoiesis and vasculogenesis, although its precise hierarchical position and function remain unknown. To gain further insight in the role of MEIS1 in megakaryopoiesis, we used a proteomics approach to search for its nuclear interaction partners. Co-immunoprecipitation was used to isolate MEIS1 interacting proteins from the nuclear fraction of the MK cell line, CHRF 288–11 and resulting eluates were subjected to proteomics analysis using one-dimensional electrophoresis and liquid chromatography (LC) coupled to tandem mass spectrometry (MS) or GeLC-MS/MS. In total 70 proteins were identified to co-immunoprecipitate with MEIS1 from 3 replicate MS analyses. These included the previously validated MEIS1 interactors PBX1 and HOXB9, as well as numerous novel interactors such as ARID3B and DHX9. Network analysis of our MEIS1 interactome dataset revealed a strong association with cell cycle regulation. In fact, we had identified a myriad of cell cycle regulators including CDK1, CDK2, CDK9, CUL3, PCNA, CDC5L, ARID3B and MDC1. These interactions are consistent with recent microarray studies in promyelocytic leukemic cell lines that link MEIS1 with cell cycle entry and its regulation of genes such as CDK2, CDK6, CDKN3, CDC7 and Cyclin D3 among others. To confirm the novel interaction of MK MEIS1 with cell cycle regulators we performed reverse immuno-precipitation/immunoblot analysis in CHRF cells and purified MEIS1 containing multiprotein complexes from L8057 murine megakaryoblastic cells. Using a cell cycle specific PCR array, we demonstrate that MEIS1 overexpression in L8057 cells regulates numerous cell cycle regulatory genes. Preliminary analysis using flow cytometry demonstrated that MEIS1 overexpression resulted in an altered cell cycle progression. Furthermore, genome wide ChIP-Seq analysis in CHRF cells for MEIS1 revealed binding sites in Cyclin D3 and CDK6, two known key regulators of the cell cycle and megakaryopoiesis. Taken together this study provides evidence linking MEIS1 to the cell cycle control of MKs and will help elucidate the role of MEIS1 in cell cycle progression, megakaryopoiesis and associated disorders. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Myxoma Virus M-T5 Protects Infected Cells from the Stress of Cell Cycle Arrest through Its Interaction with Host Cell Cullin-1

2005 ◽  
Vol 79 (16) ◽  
pp. 10750-10763 ◽  
Author(s):  
J. B. Johnston ◽  
G. Wang ◽  
J. W. Barrett ◽  
S. H. Nazarian ◽  
K. Colwill ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Cell Cycle Progression ◽  
Molecular Mechanisms ◽  
Regulatory Protein ◽  
Myxoma Virus ◽  
Cycle Progression ◽  
Cycle Arrest ◽  
Infected Cells ◽  
In Cells

ABSTRACT The myxoma virus (MV) M-T5 gene encodes an ankyrin repeat protein that is important for virus replication in cells from several species. Insight was gained into the molecular mechanisms underlying the role of M-T5 as a host range determinant when the cell cycle regulatory protein cullin-1 (cul-1) was identified as a cellular binding partner of M-T5 and found to colocalize with the protein in both nuclear and cytosolic compartments. Consistent with this interaction, infection with wild-type MV (vMyxlac) or a deletion mutant lacking M-T5 (vMyxT5KO) differentially altered cell cycle progression in a panel of permissive and nonpermissive cells. Cells infected with vMyxlac transitioned rapidly out of the G0/G1 phase and preferentially accumulated at the G2/M checkpoint, whereas infection with vMyxT5KO impeded progression through the cell cycle, resulting in a greater percentage of cells retained at G0/G1. Levels of the cul-1 substrate, p27/Kip-1, were selectively increased in cells infected with vMyxT5KO compared to vMyxlac, concurrent with decreased phosphorylation of p27/Kip-1 at Thr187 and decreased ubiquitination. Compared to cells infected with vMyxlac, cell death was increased in vMyxT5KO-infected cells following treatment with diverse stimuli known to induce cell cycle arrest, including infection itself, serum deprivation, and exposure to proteasome inhibitors or double-stranded RNA. Moreover, infection with vMyxlac, but not vMyxT5KO, was sufficient to overcome the G0/G1 arrest induced by these stimuli. These findings suggest that M-T5 regulates cell cycle progression at the G0/G1 checkpoint, thereby protecting infected cells from diverse innate host antiviral responses normally triggered by G0/G1 cell cycle arrest.

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