Silencing of both ATF4 and PERK inhibits cell cycle progression and promotes the apoptosis of differentiating chondrocytes

Wu, Zhimeng; Li, Meiling; Zheng, Wei; Hu, Qin; Cheng, Zhi; Guo, Fengjin

doi:10.3892/ijmm.2017.2985

Cited by 14 publications

(13 citation statements)

References 41 publications

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“…Zhang et al clarify that the upregulation of PERK signaling alleviates apoptosis of skeletal muscle cells under high-stress conditions of hibernation [18]. In addition, data from other studies manifests that the silencing of PERK contributes to the apoptosis of chondrocytes and pancreatic β-cells [19,20]. Our results suggested that PERK overexpression markedly inhibited H/ R-induced NCMs apoptosis, which demonstrated the cellular protective roles of PERK.…”

Section: Discussionsupporting

confidence: 67%

PERK Overexpression-Mediated Nrf2/HO-1 Pathway Alleviates Hypoxia/Reoxygenation-Induced Injury in Neonatal Murine Cardiomyocytes via Improving Endoplasmic Reticulum Stress

Wang

Lü

Chen

et al. 2020

BioMed Research International

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Reperfusion processes following acute myocardial infarction (AMI) have been reported to induce additional cardiomyocyte death, known as ischemia-reperfusion (I/R) injury. Endoplasmic reticulum (ER) stress is reported to be involved in the development of I/R injury. There is evidence that PERK exerts beneficial roles in alleviating ER stress. Here, we investigated whether upregulation of PERK improved cardiomyocytes injury induced by I/R. Specific siRNAs or adenovirus vectors were incubated with isolated neonatal cardiomyocytes (NCMs) to regulate expression levels of target genes including PERK, Nrf2, and HO-1. Afterwards, hypoxia and subsequent reoxygenation (H/R) administration was performed as the in vitro model of I/R injury. MTT assay showed that H/R intervention decreased the viability of cells, yet PERK overexpression increased the cellular proliferative rate. Moreover, the upregulation of Nrf2 or HO-1 elevated the growth rate of cells, while gene silencing of Nrf2 or HO-1 reduced the viability of NCMs treated with PERK-rAAV9. In addition, we observed that the apoptotic index of cells with H/R stimulation was reduced when NCMs were pretreated with PERK-rAAV9, Nrf2-rAAV9, or HO-1-rAAV9. After cells were incubated with Nrf2-siRNA or HO-1-siRNA, the upregulation of PERK had no roles in affecting the apoptosis rate of NCMs damaged by H/R. Then, our findings indicated that there was a level decrease of GRP78, CRT, CHOP, and Caspase-12 in NCMs of the PERK-rAAV9 group compared to that of the H/R group. Both Nrf2 overexpression and HO-1 upregulation reduced the expression of ER stress-related proapoptotic factors, yet the expression suppression of Nrf2 and HO-1 increased levels of GRP78, CRT, CHOP, and Caspase-12 in NCMs treated with PERK-rAAV9. Taken together, our results suggested that the effects of PERK against H/R injury might be attributed to the upregulation of Nrf2/HO-1 cascade, followed by the inhibition of ER stress-related apoptotic pathway.

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Section: Discussionsupporting

confidence: 67%

PERK Overexpression-Mediated Nrf2/HO-1 Pathway Alleviates Hypoxia/Reoxygenation-Induced Injury in Neonatal Murine Cardiomyocytes via Improving Endoplasmic Reticulum Stress

Wang

Lü

Chen

et al. 2020

BioMed Research International

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“…To confirm the effects of ATG5, ATG7, siPERK and siNrf2 on chondrocyte. C28I2 cells were infected with Ad-ATG5 (MOI = 80), Ad-ATG7 (MOI = 100), siPERK (50 nmol) or siNrf2 (50 nmol) and Ad-GFP prior to culture 24 h [31, 32]. pcDNA3.1(−)-ATG5 and pcDNA3.1(−)-ATG7 were transfected into cells for 24 h by liposome 8000(Invitrogen) according to the manufacturer’s protocol.…”

Section: Methodsmentioning

confidence: 99%

ATG5 and ATG7 induced autophagy interplays with UPR via PERK signaling

et al. 2019

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Background Autophagy and ER stress are involved in maintaining some well-orchestrated mechanisms aimed at either restoring cellular homeostasis or performing cell death. Autophagy is a well-defined process which governs overall cellular stress outcomes. Selective degradation of the ER mediated by autophagy occurs through a specific type of autophagy called ER-phagy, which ensures ER protein homeostasis. Methods Immunoblotting and RT-PCR were used to evaluate the expression of ATG5 and ATG7 in chondrocyte. Western blotting, Flow cytometry,immunofluorescence cell staining and confocal microscope were used to examine the effect of ATG5 and ATG7 on autophagy, ER stress, cell apoptosis and cell proliferation. Transmission electron microscope and confocal microscope were performed to visualize the autophagy flux and autolysosome formation. The role of ATG5 and ATG7 overexpression on the PERK pathway inhibitor were detected by immunoblotting and treatment with inhibitors. Results In current study, we demonstrated that Tm-induced ER stress can activate autophagy while Rapamycin-induced autophagy can inhibit ER stress in chondrocyte. Autophagy related protein ATG5 or ATG7 can promote autophagy and inhibit ER stress individually, and their combined effect can further improve the autophagy enhancement and the ER stress repression. Moreover, ATG5, ATG7 and ATG5 + ATG7 lead cells into more S phase, increase the number of S phase and inhibit apoptosis as well. ATG5, ATG7 and ATG5 + ATG7 regulate autophagy, ER stress, apoptosis and cell cycle through PERK signaling, a vital UPR branch pathway. Conclusions ATG5 and ATG7 connect autophagy with ER stress through PERK signaling. The protective effect of ATG5/7 overexpression on chondrocyte survival relys on PERK signaling. The effect of siPERK and siNrf2 on the cytoprotective effect of ATG5/7 are of synergism, while the effect of siPERK and siATF4 are of antagonism. PERK signal may be the pivot for autophagy, ER homeostasis and ER-phagy in chondrocyte. Electronic supplementary material The online version of this article (10.1186/s12964-019-0353-3) contains supplementary material, which is available to authorized users.

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“…However, sustained stress changes the adaptive response to a prodeath response and ultimately, the phosphorylation status of eIF2α appears to codetermine the balance between prosurvival or prodeath signalling . This is accomplished by the above mentioned delayed feedback through which the interplay of GADD34, ATF4 and CHOP results in the activation of genes involved in cell death, cell‐cycle arrest and senescence (Fig. ).…”

Section: Er Stress Consequencesmentioning

confidence: 99%

Endoplasmic reticulum stress signalling – from basic mechanisms to clinical applications

et al. 2018

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The endoplasmic reticulum (ER) is a membranous intracellular organelle and the first compartment of the secretory pathway. As such, the ER contributes to the production and folding of approximately one-third of cellular proteins, and is thus inextricably linked to the maintenance of cellular homeostasis and the fine balance between health and disease. Specific ER stress signalling pathways, collectively known as the unfolded protein response (UPR), are required for maintaining ER homeostasis. The UPR is triggered when ER protein folding capacity is overwhelmed by cellular demand and the UPR initially aims to restore ER homeostasis and normal cellular functions. However, if this fails, then the UPR triggers cell death. In this review, we provide a UPR signalling-centric view of ER functions, from the ER's discovery to the latest advancements in the understanding of ER and UPR biology. Our review provides a synthesis of intracellular ER signalling revolving around proteostasis and the UPR, its impact on other organelles and cellular behaviour, its multifaceted and dynamic response to stress and its role in physiology, before finally exploring the potential exploitation of this knowledge to tackle unresolved biological questions and address unmet biomedical needs. Thus, we provide an integrated and global view of existing literature on ER signalling pathways and their use for therapeutic purposes.

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Silencing of both ATF4 and PERK inhibits cell cycle progression and promotes the apoptosis of differentiating chondrocytes

Cited by 14 publications

References 41 publications

PERK Overexpression-Mediated Nrf2/HO-1 Pathway Alleviates Hypoxia/Reoxygenation-Induced Injury in Neonatal Murine Cardiomyocytes via Improving Endoplasmic Reticulum Stress

PERK Overexpression-Mediated Nrf2/HO-1 Pathway Alleviates Hypoxia/Reoxygenation-Induced Injury in Neonatal Murine Cardiomyocytes via Improving Endoplasmic Reticulum Stress

ATG5 and ATG7 induced autophagy interplays with UPR via PERK signaling

Endoplasmic reticulum stress signalling – from basic mechanisms to clinical applications

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