scholarly journals Eimeria bovis infections induce G1 cell cycle arrest and a senescence-like phenotype in endothelial host cells

Parasitology ◽  
2020 ◽  
pp. 1-13
Author(s):  
Zahady D. Velásquez ◽  
Sara López-Osorio ◽  
Daniel Waiger ◽  
Carolina Manosalva ◽  
Learta Pervizaj-Oruqaj ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Endothelial Cells ◽  
Cell Cycle Arrest ◽  
Host Cell ◽  
Cyclin B1 ◽  
Host Cells ◽  
Phenotypic Change ◽  
Cyclin E1 ◽  
Cycle Arrest ◽  
Eimeria Bovis

Abstract Apicomplexan parasites are well-known to modulate their host cells at diverse functional levels. As such, apicomplexan-induced alteration of host cellular cell cycle was described and appeared dependent on both, parasite species and host cell type. As a striking evidence of species-specific reactions, we here show that Eimeria bovis drives primary bovine umbilical vein endothelial cells (BUVECs) into a senescence-like phenotype during merogony I. In line with senescence characteristics, E. bovis induces a phenotypic change in host cell nuclei being characterized by nucleolar fusion and heterochromatin-enriched peripheries. By fibrillarin staining we confirm nucleoli sizes to be increased and their number per nucleus to be reduced in E. bovis-infected BUVECs. Additionally, nuclei of E. bovis-infected BUVECs showed enhanced signals for HH3K9me2 as heterochromatin marker thereby indicating an infection-induced change in heterochromatin transition. Furthermore, E. bovis-infected BUVECs show an enhanced β-galactosidase activity, which is a well-known marker of senescence. Referring to cell cycle progression, protein abundance profiles in E. bovis-infected endothelial cells revealed an up-regulation of cyclin E1 thereby indicating a cell cycle arrest at G1/S transition, signifying a senescence key feature. Similarly, abundance of G2 phase-specific cyclin B1 was found to be downregulated at the late phase of macromeront formation. Overall, these data indicate that the slow proliferative intracellular parasite E. bovis drives its host endothelial cells in a senescence-like status. So far, it remains to be elucidated whether this phenomenon indeed reflects an intentionally induced mechanism to profit from host cell-derived energy and metabolites present in a non-dividing cellular status.

scholarly journals The Severe Fever with Thrombocytopenia Syndrome Virus NSs Protein Interacts with CDK1 To Induce G2 Cell Cycle Arrest and Positively Regulate Viral Replication

2019 ◽  
Vol 94 (6) ◽  
Author(s):  
Sihua Liu ◽  
Hongyun Liu ◽  
Jun Kang ◽  
Leling Xu ◽  
Keke Zhang ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Viral Replication ◽  
Cell Cycle Arrest ◽  
Host Cell ◽  
Nuclear Import ◽  
Hemorrhagic Fever ◽  
Cyclin B1 ◽  
Cycle Arrest ◽  
Infected Cells ◽  
Severe Fever

ABSTRACT Severe fever with thrombocytopenia syndrome virus (SFTSV) is a newly identified phlebovirus associated with severe hemorrhagic fever in humans. While many viruses subvert the host cell cycle to promote viral growth, it is unknown whether this is a strategy employed by SFTSV. In this study, we investigated how SFTSV manipulates the cell cycle and the effect of the host cell cycle on SFTSV replication. Our results suggest that cells arrest at the G2/M transition following infection with SFTSV. The accumulation of cells at the G2/M transition did not affect virus adsorption and entry but did facilitate viral replication. In addition, we found that SFTSV NSs, a nonstructural protein that forms viroplasm-like structures in the cytoplasm of infected cells and promotes virulence by modulating the interferon response, induces a large number of cells to arrest at the G2/M transition by interacting with CDK1. The interaction between NSs and CDK1, which is inclusion body dependent, inhibits formation and nuclear import of the cyclin B1-CDK1 complex, thereby leading to cell cycle arrest. Expression of a CDK1 loss-of-function mutant reversed the inhibitive effect of NSs on the cell cycle, suggesting that this protein is a potential antiviral target. Our study provides new insight into the role of a specific viral protein in SFTSV replication, indicating that NSs induces G2/M arrest of SFTSV-infected cells, which promotes viral replication. IMPORTANCE Severe fever with thrombocytopenia syndrome virus (SFTSV) is a tick-borne pathogen that causes severe hemorrhagic fever. Although SFTSV poses a serious threat to public health and was recently isolated, its pathogenesis remains unclear. In particular, the relationship between SFTSV infection and the host cell cycle has not been described. Here, we show for the first time that both asynchronized and synchronized SFTSV-susceptible cells arrest at the G2/M checkpoint following SFTSV infection and that the accumulation of cells at this checkpoint facilitates viral replication. We also identify a key mechanism underlying SFTSV-induced G2/M arrest, in which SFTSV NSs interacts with CDK1 to inhibit formation and nuclear import of the cyclin B1-CDK1 complex, thus preventing it from regulating cell cycle progression. Our study highlights the key role that NSs plays in SFTSV-induced G2/M arrest.

scholarly journals Identification of the Secretion and Translocation Domain of the Enteropathogenic and Enterohemorrhagic Escherichia coli Effector Cif, Using TEM-1 β-Lactamase as a New Fluorescence-Based Reporter

2004 ◽  
Vol 186 (16) ◽  
pp. 5486-5495 ◽  
Author(s):  
Xavier Charpentier ◽  
Eric Oswald
Keyword(s):  
Escherichia Coli ◽  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Host Cell ◽  
Effector Proteins ◽  
Host Cells ◽  
Reporter System ◽  
Type Iii ◽  
Cycle Arrest ◽  
Lambdoid Prophage

ABSTRACT Enteropathogenic and enterohemorrhagic Escherichia coli (EPEC and EHEC) strains are human and animal pathogens that inject effector proteins into host cells via a type III secretion system (TTSS). Cif is an effector protein which induces host cell cycle arrest and reorganization of the actin cytoskeleton. Cif is encoded by a lambdoid prophage present in most of the EPEC and EHEC strains. In this study, we analyzed the domain that targets Cif to the TTSS by using a new reporter system based on a translational fusion of the effector proteins with mature TEM-1 β-lactamase. Translocation was detected directly in living host cells by using the fluorescent β-lactamase substrate CCF2/AM. We show that the first 16 amino acids (aa) of Cif were necessary and sufficient to mediate translocation into the host cells. Similarly, the first 20 aa of the effector proteins Map, EspF, and Tir, which are encoded in the same region as the TTSS, mediated secretion and translocation in a type III-dependent but chaperone-independent manner. A truncated form of Cif lacking its first 20 aa was no longer secreted and translocated, but fusion with the first 20 aa of Tir, Map, or EspF restored both secretion and translocation. In addition, the chimeric proteins were fully able to trigger host cell cycle arrest and stress fiber formation. In conclusion, our results demonstrate that Cif is composed of a C-terminal effector domain and an exchangeable N-terminal translocation signal and that the TEM-1 reporter system is a convenient tool for the study of the translocation of toxins or effector proteins into host cells.

scholarly journals The Antiangiogenic Factor, 16-kDa Human Prolactin, Induces Endothelial Cell Cycle Arrest by Acting at Both the G0–G1 and the G2–M Phases

2005 ◽  
Vol 19 (7) ◽  
pp. 1932-1942 ◽  
Author(s):  
Sébastien P. Tabruyn ◽  
Ngoc-Quynh-Nhu Nguyen ◽  
Anne M. Cornet ◽  
Joseph A. Martial ◽  
Ingrid Struman
Keyword(s):  
Cell Cycle ◽  
Endothelial Cells ◽  
Cyclin D1 ◽  
Cell Cycle Arrest ◽  
Glycogen Synthase ◽  
Mapk Pathway ◽  
Mrna Level ◽  
Cyclin B1 ◽  
Cycle Arrest ◽  
Human Prolactin

Abstract The 16-kDa N-terminal fragment of human prolactin (16K hPRL) is a potent antiangiogenic factor that has been shown to prevent tumor growth in a xenograph mouse model. In this paper we first demonstrate that 16K hPRL inhibits serum-induced DNA synthesis in adult bovine aortic endothelial cells. This inhibition is associated with cell cycle arrest at both the G0–G1 and the G2–M phase. Western blot analysis revealed that 16K hPRL strongly decreases levels of cyclin D1 and cyclin B1, but not cyclin E. The effect on cyclin D1 is at least partially transcriptional, because treatment with 16K hPRL both reduces the cyclin D1 mRNA level and down-regulates cyclin D1 promoter activity. This regulation may be due to inhibition of the MAPK pathway, but it is independent of the glycogen synthase kinase-3β pathway. Lastly, 16K hPRL induces the expression of negative cell cycle regulators, the cyclin-dependent kinase inhibitors p21(cip1) and p27(kip1). In summary, 16K hPRL inhibits serum-induced proliferation of endothelial cells through combined effects on positive and negative regulators of cell cycle progression.

scholarly journals Skp2 Regulates G2/M Progression in a p53-dependent Manner

2008 ◽  
Vol 19 (11) ◽  
pp. 4602-4610 ◽  
Author(s):  
Rong Hu ◽  
Andrew E. Aplin
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Cyclin B1 ◽  
Melanoma Cells ◽  
Dependent Manner ◽  
Wild Type ◽  
Induce Cell Cycle Arrest ◽  
P53 Expression ◽  
Cyclin E1 ◽  
Cycle Arrest

Targeted proteasomal degradation mediated by E3 ubiquitin ligases controls cell cycle progression, and alterations in their activities likely contribute to malignant cell proliferation. S phase kinase-associated protein 2 (Skp2) is the F-box component of an E3 ubiquitin ligase complex that targets p27Kip1 and cyclin E1 to the proteasome. In human melanoma, Skp2 is highly expressed, regulated by mutant B-RAF, and required for cell growth. We show that Skp2 depletion in melanoma cells resulted in a tetraploid cell cycle arrest. Surprisingly, co-knockdown of p27Kip1 or cyclin E1 failed to prevent the tetraploid arrest induced by Skp2 knockdown. Enhanced Aurora A phosphorylation and repression of G2/M regulators cyclin B1, cyclin-dependent kinase 1, and cyclin A indicated a G2/early M phase arrest in Skp2-depleted cells. Furthermore, expression of nuclear localized cyclin B1 prevented tetraploid accumulation after Skp2 knockdown. The p53 status is most frequently wild type in melanoma, and the tetraploid arrest and down-regulation of G2/M regulatory genes were strongly dependent on wild-type p53 expression. In mutant p53 melanoma lines, Skp2 depletion did not induce cell cycle arrest despite up-regulation of p27Kip1. These data indicate that elevated Skp2 expression may overcome p53-dependent cell cycle checkpoints in melanoma cells and highlight Skp2 actions that are independent of p27Kip1 degradation.

scholarly journals VEGFC/FLT4-induced cell-cycle arrest mediates sprouting and differentiation of venous and lymphatic endothelial cells

Cell Reports ◽  
2021 ◽  
Vol 35 (11) ◽  
pp. 109255
Author(s):  
Ayelet Jerafi-Vider ◽  
Ivan Bassi ◽  
Noga Moshe ◽  
Yaara Tevet ◽  
Gideon Hen ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Endothelial Cells ◽  
Cell Cycle Arrest ◽  
Lymphatic Endothelial Cells ◽  
Cycle Arrest

scholarly journals Eimeria tenella ROP kinase EtROP1 induces G0/G1 cell cycle arrest and inhibits host cell apoptosis

2019 ◽  
Vol 21 (7) ◽  
Author(s):  
Mamadou Amadou Diallo ◽  
Alix Sausset ◽  
Audrey Gnahoui‐David ◽  
Adeline Ribeiro E Silva ◽  
Aurélien Brionne ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Host Cell ◽  
Cell Apoptosis ◽  
Eimeria Tenella ◽  
Cycle Arrest ◽  
Host Cell Apoptosis ◽  
G1 Cell Cycle Arrest

scholarly journals The Novel Nature Microtubule Inhibitor Ivalin Induces G2/M Arrest and Apoptosis in Human Hepatocellular Carcinoma SMMC-7721 Cells In Vitro

Medicina ◽  
2019 ◽  
Vol 55 (8) ◽  
pp. 470 ◽  
Author(s):  
Fangyuan Liu ◽  
Shiqi Lin ◽  
Caiyun Zhang ◽  
Jiahui Ma ◽  
Zhuo Han ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Western Blotting ◽  
Network Formation ◽  
Cyclin B1 ◽  
Human Hepatocellular Carcinoma ◽  
Microtubule Depolymerization ◽  
Microtubule Network ◽  
Cycle Arrest

Background and Objectives: Microtubules are an attractive target for cancer chemotherapy. Previously, we reported that Ivalin exhibited excellent anti-migration and anti-invasion activities in human breast cancer cells. Here, we examined the microtubule inhibition effect of Ivalin in human hepatocellular carcinoma SMMC-7721 cells. Materials and Methods: We used the 3-(4,5-dimethylthiazol)-2,5-diphenyltetrazolium bromide (MTT) assay to evaluate the cell proliferation effect of Ivalin and flow cytometry analysis to detect the apoptotic and cell cycle arrest effects of Ivalin. Immunofluorescence staining was used to measure the effect of Ivalin on the cytoskeleton network, and Western blotting was used to detect the expression levels of Bax, Bcl-2, Cdc2, phosphor-Cdc2, Cdc25A, Cyclin B1, and tubulin. Results: Ivalin induced cell cycle G2/M arrest and subsequent triggered apoptosis in human hepatocellular carcinoma SMMC-7721 cells. Furthermore, microtubules were shown to be involved in Ivalin-meditated apoptosis. In this connection, Ivalin treatment suppressed cellular microtubule network formation by regulating microtubule depolymerization. Moreover, Western blotting revealed Cdc25A and Cyclin B1 were upregulated in Ivalin-meditated cell cycle arrest. Subsequently, the induction of Bax (a proapoptotic protein) and reduction of Bcl-2 (an anti-apoptotic protein) expression were observed in Ivalin-treated SMMC-7721 cells. Conclusion: Ivalin induced microtubule depolymerization, then blocked cells in mitotic phase, and eventually resulted in apoptosis in SMMC-7721 cells. Collectively, these data indicate that Ivalin, acting as a novel inhibitor of microtubules, could be considered as a promising lead in anticancer drug development.

scholarly journals TR3 Orphan Receptor Is Expressed in Vascular Endothelial Cells and Mediates Cell Cycle Arrest

2003 ◽  
Vol 23 (9) ◽  
pp. 1535-1540 ◽  
Author(s):  
E. Karin Arkenbout ◽  
Maaike van Bragt ◽  
Eric Eldering ◽  
Chris van Bree ◽  
Jos M. Grimbergen ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Endothelial Cells ◽  
Cell Cycle Arrest ◽  
Vascular Endothelial Cells ◽  
Orphan Receptor ◽  
Vascular Endothelial ◽  
Cycle Arrest

scholarly journals Microparticles Induce Cell Cycle Arrest Through Redox‐Sensitive Processes in Endothelial Cells: Implications in Vascular Senescence

2012 ◽  
Vol 1 (3) ◽  
Author(s):  
Dylan Burger ◽  
Dylan G. Kwart ◽  
Augusto C. Montezano ◽  
Naomi C. Read ◽  
Christopher R.J. Kennedy ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Endothelial Cells ◽  
Cell Cycle Arrest ◽  
Induce Cell Cycle Arrest ◽  
Cycle Arrest ◽  
Vascular Senescence

SMBA1, a Bax Activator, Induces Cell Cycle Arrest and Apoptosis in Malignant Glioma Cells

Pharmacology ◽  
2019 ◽  
Vol 105 (3-4) ◽  
pp. 164-172
Author(s):  
Shuangbo Fan ◽  
Qian Xu ◽  
Liang Wang ◽  
Yulin Wan ◽  
Sheng Qiu
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Biological Effects ◽  
Cyclin B1 ◽  
Dependent Manner ◽  
Apoptosis Pathway ◽  
Cycle Arrest ◽  
Intrinsic Apoptosis Pathway ◽  
Induced Apoptosis ◽  
Dose Dependent

SMBA1 (small-molecule Bax agonists 1), a small molecular activator of Bax, is a potential anti-tumour agent. In the present study, we investigated the biological effects of SMBA1 on glioblastoma (GBM) cells. SMBA1 reduced the viabilities of U87MG, U251 and T98G cells in a time- and dose-dependent manner. Moreover, treatment with SMBA1 induced cell cycle arrest at the G2/M phase transition, accompanied by the downregulation of Cdc25c and cyclin B1 and the upregulation of p21. SMBA1 also induced apoptosis of GBM cells in a dose-dependent manner. Mechanistically, SMBA1 induced apoptosis via the intrinsic pathway. Silencing of Bax or ectopic expression of Bcl-2 significantly inhibited SMBA1-induced apoptosis. Moreover, SMBA1 inhibited the growth of U87MG xenograft tumours in vivo. Overall, SMBA1 shows anti-proliferative effects against GBM cells through activation of the intrinsic apoptosis pathway.

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