scholarly journals Sympathetic nerve activity promotes cardiomyocyte cell-cycle arrest and binucleation

2017 ◽  
Author(s):  
Li Chen ◽  
Alexander Y. Payumo ◽  
Kentaro Hirose ◽  
Rachel B. Bigley ◽  
Jonathan Lovas ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Sympathetic Nerve ◽  
Adrenergic Receptors ◽  
Sympathetic Nerve Activity ◽  
Cardiomyocyte Proliferation ◽  
Nerve Activity ◽  
Cycle Arrest ◽  
Β Adrenergic Receptors

ABSTRACTAdult mammalian hearts typically have little capacity to regenerate after injuries such as myocardial infarction. In contrast, neonatal mice during the first week of life possess an incredible ability to regenerate their hearts, though this capacity is lost shortly after birth. The physiological triggers mediating this transition remains poorly understood. In this study, we demonstrate that sympathetic nerve activity promotes cardiomyocyte cell-cycle arrest and binucleation. In mice hearts lacking sympathetic nerve inputs, we observe increased mononucleated cardiomyocyte numbers and elevated cardiomyocyte proliferation. Additionally, increased cardiomyocyte mononucleation and proliferation are observed in mice with genetic and pharmacological inhibition of β-adrenergic receptors (βARs), which mediate sympathetic nerve signaling. Using in vitro cultures of neonatal cardiomyocytes, we demonstrate that activation of β-adrenergic receptors results in decreased cardiomyocyte proliferation that is mediated through cyclic AMP-dependent protein kinase (PKA) signaling. Taken together, these results suggest that sympathetic nerve activity may play a role in limiting the ability of mammalian hearts to regenerate by restricting cardiomyocyte proliferation and promoting cytokinesis failure leading to multinucleation.

scholarly journals HIV-1 Vpr activates host CRL4-DCAF1 E3 ligase to degrade histone deacetylase SIRT7

2021 ◽  
Vol 18 (1) ◽  
Author(s):  
Xiaohong Zhou ◽  
Christina Monnie ◽  
Maria DeLucia ◽  
Jinwoo Ahn
Keyword(s):  
Cell Cycle ◽  
Dna Repair ◽  
Cell Cycle Arrest ◽  
Histone Deacetylase ◽  
E3 Ligase ◽  
Cycle Arrest ◽  
Wide Range ◽  
In Vitro Reconstitution ◽  
Hiv 1

Abstract Background Vpr is a virion-associated protein that is encoded by lentiviruses and serves to counteract intrinsic immunity factors that restrict infection. HIV-1 Vpr mediates proteasome-dependent degradation of several DNA repair/modification proteins. Mechanistically, Vpr directly recruits cellular targets onto DCAF1, a substrate receptor of Cullin 4 RING E3 ubiquitin ligase (CRL4) for poly-ubiquitination. Further, Vpr can mediate poly-ubiquitination of DCAF1-interacting proteins by the CRL4. Because Vpr-mediated degradation of its known targets can not explain the primary cell-cycle arrest phenotype that Vpr expression induces, we surveyed the literature for DNA-repair-associated proteins that interact with the CRL4-DCAF1. One such protein is SIRT7, a deacetylase of histone 3 that belongs to the Sirtuin family and regulates a wide range of cellular processes. We wondered whether Vpr can mediate degradation of SIRT7 via the CRL4-DCAF1. Methods HEK293T cells were transfected with cocktails of plasmids expressing DCAF1, DDB1, SIRT7 and Vpr. Ectopic and endogeneous levels of SIRT7 were monitered by immunoblotting and protein–protein interactions were assessed by immunoprecipitation. For in vitro reconstitution assays, recombinant CRL4-DCAF1-Vpr complexes and SIRT7 were prepared and poly-ubiqutination of SIRT7 was monitored with immunoblotting. Results We demonstrate SIRT7 polyubiquitination and degradation upon Vpr expression. Specifically, SIRT7 is shown to interact with the CRL4-DCAF1 complex, and expression of Vpr in HEK293T cells results in SIRT7 degradation, which is partially rescued by CRL inhibitor MNL4924 and proteasome inhibitor MG132. Further, in vitro reconstitution assays show that Vpr induces poly-ubiquitination of SIRT7 by the CRL4-DCAF1. Importantly, we find that Vpr from several different HIV-1 strains, but not HIV-2 strains, mediates SIRT7 poly-ubiquitination in the reconstitution assay and degradation in cells. Finally, we show that SIRT7 degradation by Vpr is independent of the known, distinctive phenotype of Vpr-induced cell cycle arrest at the G2 phase, Conclusions Targeting histone deacetylase SIRT7 for degradation is a conserved feature of HIV-1 Vpr. Altogether, our findings reveal that HIV-1 Vpr mediates down-regulation of SIRT7 by a mechanism that does not involve novel target recruitment to the CRL4-DCAF1 but instead involves regulation of the E3 ligase activity.

Synthesis, cytotoxicity in vitro, apoptosis, cell cycle arrest and comet assay of asymmetry ruthenium(II) complexes

Polyhedron ◽  
2016 ◽  
Vol 106 ◽  
pp. 115-124 ◽  
Author(s):  
Cheng Zhang ◽  
Chuan-Chuan Zeng ◽  
Shang-Hai Lai ◽  
De-Gang Xing ◽  
Wei Li ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Comet Assay ◽  
Cell Cycle Arrest ◽  
Cycle Arrest

Evaluation of deoxynivalenol-induced toxic effects on DF-1 cells in vitro: Cell-cycle arrest, oxidative stress, and apoptosis

2014 ◽  
Vol 37 (1) ◽  
pp. 141-149 ◽  
Author(s):  
Daotong Li ◽  
Yaqiong Ye ◽  
Shaoqing Lin ◽  
Li Deng ◽  
Xiaolong Fan ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Toxic Effects ◽  
Cycle Arrest

scholarly journals Apoptosis Induction, Cell Cycle Arrest and in Vitro Anticancer Activity of Gonothalamin in a Cancer Cell Lines

2012 ◽  
Vol 13 (10) ◽  
pp. 5131-5136 ◽  
Author(s):  
Aied M. Alabsi ◽  
Rola Ali ◽  
Abdul Manaf Ali ◽  
Sami Abdo Radman Al-Dubai ◽  
Hazlan Harun ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Anticancer Activity ◽  
Cell Cycle Arrest ◽  
Cell Lines ◽  
Cancer Cell ◽  
Cancer Cell Lines ◽  
Apoptosis Induction ◽  
Cycle Arrest

scholarly journals The innate immune sensor Toll-like receptor 2 controls the senescence-associated secretory phenotype

2018 ◽  
Author(s):  
Priya Hari ◽  
Fraser R. Millar ◽  
Nuria Tarrats ◽  
Jodie Birch ◽  
Curtis J. Rink ◽  
...  
Keyword(s):  
Cell Cycle ◽  
Cell Cycle Arrest ◽  
Innate Immune ◽  
Toll Like Receptor ◽  
Cycle Arrest ◽  
Secretory Phenotype ◽  
Immune Sensing ◽  
Molecular Patterns ◽  
Innate Immune Sensing

ABSTRACTCellular senescence is a stress response program characterised by a robust cell cycle arrest and the induction of a pro-inflammatory senescence-associated secretory phenotype (SASP) that is triggered through an unknown mechanism. Here, we show that during oncogene-induced senescence (OIS), the Toll-like receptor TLR2 and its partner TLR10 are key mediators of senescence in vitro and in murine models. TLR2 promotes cell cycle arrest by regulating the tumour suppressors p53-p21CIP1, p16INK4a and p15INK4b, and regulates the SASP through the induction of the acute-phase serum amyloids A1 and A2 (A-SAA) that, in turn, function as the damage associated molecular patterns (DAMPs) signalling through TLR2 in OIS. Finally, we found evidence that the cGAS-STING cytosolic DNA sensing pathway primes TLR2 and A-SAA expression in OIS. In summary, we report that innate immune sensing of senescence-associated DAMPs by TLR2 controls the SASP and reinforces the cell cycle arrest program in OIS.

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