GSK-3β down-regulates the transcription factor Nrf2 after oxidant damage: relevance to exposure of neuronal cells to oxidative stress

ABSTRACT Heat shock transcription factor 1 (HSF-1) activates the transcription of heat shock genes in eukaryotes. Under normal physiological growth conditions, HSF-1 is a monomer. Its transcriptional activity is repressed by constitutive phosphorylation. Upon activation, HSF-1 forms trimers, acquires DNA binding activity, increases transcriptional activity, and appears as punctate granules in the nucleus. In this study, using bromouridine incorporation and confocal laser microscopy, we demonstrated that newly synthesized pre-mRNAs colocalize to the HSF-1 punctate granules after heat shock, suggesting that these granules are sites of transcription. We further present evidence that glycogen synthase kinase 3β (GSK-3β) and extracellular signal-regulated kinase mitogen-activated protein kinase (ERK MAPK) participate in the down regulation of HSF-1 transcriptional activity. Transient increases in the expression of GSK-3β facilitate the disappearance of HSF-1 punctate granules and reduce hsp-70 transcription after heat shock. We have also shown that ERK is the priming kinase for GSK-3β. Taken together, these results indicate that GSK-3β and ERK MAPK facilitate the inactivation of activated HSF-1 after heat shock by dispersing HSF-1 from the sites of transcription.

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Pirlindole and dehydropirlindole protect rat cultured neuronal cells against oxidative stress-induced cell death through a mechanism unrelated to MAO-A inhibition

British Journal of Pharmacology ◽

10.1038/sj.bjp.0704519 ◽

2002 ◽

Vol 135 (3) ◽

pp. 713-720 ◽

Cited By ~ 9

Author(s):

A Boland ◽

J Gérardy ◽

D Mossay ◽

D Delapierre ◽

V Seutin

Keyword(s):

Oxidative Stress ◽

Cell Death ◽

Neuronal Cells ◽

Mao A

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PERK mediates oxidative stress and adipogenesis in Graves’ orbitopathy pathogenesis

Journal of Molecular Endocrinology ◽

10.1530/jme-21-0057 ◽

2021 ◽

Author(s):

JaeSang Ko ◽

Ji-Young Kim ◽

Min Kyung Chae ◽

Eun Jig Lee ◽

Jin Sook Yoon

Keyword(s):

Oxidative Stress ◽

Hydrogen Peroxide ◽

Endoplasmic Reticulum ◽

Transcription Factor ◽

Er Stress ◽

Adipogenic Differentiation ◽

Ros Generation ◽

Mrna Levels ◽

Graves Orbitopathy ◽

Orbital Fibroblasts

We examined endoplasmic reticulum (ER) stress-related gene expression in orbital tissues from patients with Graves’ orbitopathy (GO) and the effects of silencing protein kinase RNA-like endoplasmic reticulum kinase (PERK) in primary orbital fibroblast cultures to demonstrate the therapeutic potential of PERK-modulating agents in GO management. The expression of ER stress related genes in orbital tissue harvested from individuals with or without GO was studied using real-time polymerase chain reaction. The role of PERK in GO pathogenesis was examined through small-interfering RNA (siRNA)-mediated silencing in cultured primary orbital fibroblasts. Intracellular reactive oxygen species (ROS) levels induced in response to cigarette smoke extract (CSE) or hydrogen peroxide were measured using 5-(and 6)-carboxy-20,70-dichlorodihydrofluorescein diacetate staining and flow cytometry. Cells were stained with Oil Red O, and adipogenesis-related transcription factor expression was evaluated through western blotting after adipogenic differentiation. PERK, activating transcription factor 4 (ATF4), and CCAAT-enhancer-binding protein (C/EBP)-homologous protein(CHOP)mRNA levels were significantly higher in GO orbital tissues than in non-GO orbital tissues. PERK silencing inhibited CSE- or hydrogen peroxide-induced ROS generation. After adipogenic differentiation, GO orbital fibroblasts revealed decreased lipid droplets and downregulation of C/EBPα, C/EBPβ, and peroxisome proliferator-activator gamma (PPARγ) in PERK siRNA-transfected cells. The orbital tissues of patients with GO were exposed to chronic ER stress and subsequently exhibited enhanced unfolded protein response (especially through the PERK pathway). PERK silencing reduced oxidative stress and adipogenesis in GO orbital fibroblasts in vitro. Our results imply that PERK-modulating agents can potentially be used to manage GO.

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Protective effect of GSK-3β/Nrf2 mediated by dimethyl fumarate in middle cerebral artery embolization reperfusion rat model

Current Neurovascular Research ◽

10.2174/1567202618666211109105024 ◽

2021 ◽

Vol 18 ◽

Author(s):

Yuan Li ◽

Lan Chu ◽

Chunfeng Liu ◽

Zongyi Zha ◽

Yuanlu Shu

Keyword(s):

Oxidative Stress ◽

Protective Effect ◽

Sham Group ◽

Infarct Volume ◽

Dimethyl Fumarate ◽

Control Group ◽

Related Factor ◽

Nissl Staining ◽

Gsk 3Β ◽

Nrf2 Expression

Aim: This study investigated the protective effect of dimethyl fumarate (DMF) in rats by mediating GSK3-β/Nrf2 using the middle cerebral artery embolization reperfusion (MCAO/R) rat model. Background: After an acute ischemic stroke (AIS), oxidative stress occurs. Dimethyl fumarate (DMF), a nuclear factor-E2-related factor 2 (Nrf2) activator, approved by the US Food and Drug Administration (FDA), was observed to regulate the Nrf2 pathway by acting as an anti-oxidative stress agent; however, whether this agent is involved in inhibiting GSK-3β remains to be established. Methods: DMF model was used to explore the effects of GSK-3β on Nrf2 expression level, Nrf2-ARE binding activity and Nrf2/ARE downstream expression level of anti-oxidant stress protein in Cerebral ischemia-reperfusion injury (CIRI). 60 rats were randomly divided into Sham group, MCAO/R group, solvent control group (DMSO group) and DMF treatment group, with 15 rats in each group. The MCAO/R, DMSO and DMF groups were considered in the MCAO/R model using the modified thread embolization method. In contrast, the Sham group was only anaesthetized and disinfected, and tissue muscle was dissected without inserting suture emboli. DMF group was gavaged with 45mg/kg per day of DMF, DMSO control group was gavaged with DMSO of equal volume, while MCAO/R group was only modeled without any intragastric treatment. The rats were treated seven days after the operation, and a neurological function Longa score was estimated. The rats were sacrificed seven days later, and the infarct volume was assessed by TTC staining. Hematoxylin-eosin (HE) staining was used to observe the pathological changes in rat brain tissue. Nissl staining was used to observe the expression of neurons in the infarcted cortex. Western blotting (WB) was used to observe the protein expression levels of glycogen synthase kinase 3β(GSK-3β), nuclear factor E2-related factor 2 (Nrf2), downstream heme oxygenase 1 (HO1) and NADPH quinone oxidoreductase 1 (NQO1) in four groups. The expression levels of GSK-3β and Nrf2 in the four groups were observed by immunohistochemistry and immunofluorescence. Results: (1) The Longa score of the MCAO/R, DMSO and DMF groups was found to be higher compared to the Sham group, indicating successful operation. The Longa score of the DMF group was lower than that of the other three groups 4-7 days after surgery (P<0.05). (2) HE and Nissl staining showed that the DMF group had lower neuron necrosis and higher gliosis compared to the control groups. (3) TTC staining results showed that the infarct volume of the DMF group was significantly smaller than the MCAO/R and DMSO groups. (4) Protein results showed that the GSK-3β expression in the DMF group was lower than that in all groups, while the expression of Nrf2, HO1 and NQO1 was higher compared to other groups. Conclusion: DMF can reduce neurological deficits and infarct size in the MCAO/R model. The protective effect may be related to decreased GSK-3β expression and increased Nrf2 expression, which may play a role in anti-oxidative stress.

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