scholarly journals Prevention of JNK Phosphorylation as a Mechanism for Rosiglitazone in Neuroprotection after Transient Cerebral Ischemia: Activation of Dual Specificity Phosphatase

2012 ◽  
Vol 33 (1) ◽  
pp. 106-114 ◽  
Author(s):  
Nobuya Okami ◽  
Purnima Narasimhan ◽  
Hideyuki Yoshioka ◽  
Hiroyuki Sakata ◽  
Gab Seok Kim ◽  
...  
Keyword(s):  
Cerebral Ischemia ◽  
Brain Tissue ◽  
Cortical Neurons ◽  
Neuroprotective Effect ◽  
Mitogen Activated Protein Kinase ◽  
Ischemic Brain ◽  
Dual Specificity Phosphatase ◽  
Dual Specificity ◽  
Pparγ Agonist ◽  
Ischemic Brain Tissue

Rosiglitazone, a synthetic peroxisome proliferator-activated receptor-γ (PPARγ) agonist, prevents cell death after cerebral ischemia in animal models, but the underlying mechanism has not been clarified. In this study, we examined how rosiglitazone protects neurons against ischemia. Mice treated with rosiglitazone were subjected to 60 minutes of focal ischemia followed by reperfusion. Rosiglitazone reduced infarct volume after ischemia and reperfusion. We show that this neuroprotective effect was reversed with a PPARgM antagonist. Western blot analysis showed a significant increase in expression of phosphorylated stress-activated protein kinases (c-Jun N-terminal kinase (JNK) and p38) in ischemic brain tissue. Rosiglitazone blocked this increase. Furthermore, we observed that rosiglitazone increased expression of the dual-specificity phosphatase 8 (DUSP8) protein and messenger RNA in ischemic brain tissue. Dual-specificity phosphatase 8 is a mitogen-activated protein kinase phosphatase that can dephosphorylate JNK and p38. Another key finding of the present study was that knockdown of DUSP8 in primary cultured cortical neurons that were subjected to oxygen–glucose deprivation diminished rosiglitazone's effect on downregulation of JNK phosphorylation. Thus, rosiglitazone's neuroprotective effect after ischemia is mediated by blocking JNK phosphorylation induced by ischemia via DUSP8 upregulation.

scholarly journals Ghrelin reduces cerebral ischemic injury in rats by reducing M1 microglia/macrophages

2022 ◽  
Vol 66 (1) ◽  
Author(s):  
Rong Tian ◽  
Gengsheng Mao
Keyword(s):  
Cerebral Ischemia ◽  
Brain Tissue ◽  
Infarct Volume ◽  
Neurological Function ◽  
Tunel Staining ◽  
Triphenyltetrazolium Chloride ◽  
Ischemic Brain ◽  
Tnf Α ◽  
Ischemic Brain Tissue ◽  
The Brain

The purpose of this study was to investigate the effect of Ghrelin on the polarization of microglia/ macrophages after cerebral ischemia (CI) in rats. 60 wild-type SD rats were randomly divided into sham group, CI group, CI+Ghrelin group, 20 rats in each group. The modified Longa suture method was used to establish the middle cerebral artery occlusion (MCAO) model in rats. Before surgery, Ghrelin was injected subcutaneously (100μg/kg, twice a day) for 4 consecutive weeks. After modeling, neurological function scores were performed with three behavioral experiments: mNSS score, Corner test, and Rotarod test, to evaluate the recovery of neurological function after Ghrelin treatment. At the same time, the brain tissues were collected and stained with 2,3,5-triphenyltetrazolium chloride (TTC) to detect the cerebral infarct volume. RT-qPCR was used to detect the expression of TNF-α and IL-1β in the ischemic brain tissue, and the TUNEL staining was used to detect the apoptosis of brain tissue. Flow cytometry was used to detect the percentage of M1 type microglia/macrophages which were isolated by trypsin digestion of fresh cerebral cortex. Then, the Western blotting and immunofluorescence method were used to detect the phosphorylation level of AKT (P-AKT) and AKT. Compared with the CI group, the neurological function of the rats in the CI+Ghrelin group was dramatically improved, and the cerebral infarction area was dramatically reduced. At the same time, the expression of TNF-α and IL-1β in the ischemic brain tissue of rats in the CI+Ghrelin group decreased, and the apoptotic cells in the brain tissue also decreased. Compared with the CI treatment group, the activation of M1 microglia/macrophages in the cortex of the ischemic side of the infarct and the peri-infarct area in the CI+Ghrelin group was dramatically inhibited. At the same time, the ratio of P-AKT/AKT of the brain tissue in the CI+Ghrelin group was dramatically higher than that of the CI group. In the rat cerebral ischemia model, Ghrelin can promote the repair of brain damage and the recovery of neurological function after ischemia. Its mechanism may be related to activating AKT to selectively reduce M1 microglia/macrophages, reducing inflammation and cell apoptosis in brain tissue.

scholarly journals Neuroprotective and antioxidative effects of pioglitazone in brain tissue adjacent to the ischemic core are mediated by PI3K/Akt and Nrf2/ARE pathways

2021 ◽  
Author(s):  
Yi Zhao ◽  
Ulf Lützen ◽  
Peter Gohlke ◽  
Ping Jiang ◽  
Thomas Herdegen ◽  
...  
Keyword(s):  
Brain Tissue ◽  
Cortical Neurons ◽  
Antioxidant Response ◽  
Akt Pathway ◽  
Antioxidant Response Element ◽  
Neuroprotective Effects ◽  
Primary Cortical Neurons ◽  
Ischemic Brain ◽  
Ischemic Brain Tissue ◽  
Neuronal Pc12 Cells

Abstract The present study elucidates the neuroprotective mechanisms of the PPARγ (peroxisome proliferator-activated receptor γ) agonist pioglitazone in survival of ischemic neurons following middle cerebral artery occlusion with reperfusion (MCAO). Intracerebroventricular infusion of pioglitazone over 5 days before and 24 or 48 h after MCAO alleviated neurological impairments, inhibited apoptosis 24 h, and activated the PI3K/Akt pathway along with increased phosphorylation of Akt (ser473) and GSK-3β (ser9) in the peri-infarct cortical areas 48 h after MCAO. In primary cortical neurons, pioglitazone suppressed the glutamate-induced release of lactate dehydrogenase by a PPARγ-dependent mechanism. This protective effect was reversed after co-treatment with PI3K and Akt inhibitors, LY294002 and SH-6, respectively. Pioglitazone enhanced the expression of the antioxidative transcription factor Nrf2 and its target gene protein, heme oxidase-1, in the peri-infarct area. Pioglitazone also increased activation of the antioxidant response element (ARE) in neuronal PC12 cells transfected with the pNQO1-rARE plasmid. We demonstrate in primary cortical neurons from Nrf2 knockout mice that the lack of Nrf2 completely abolished the neuroprotective effects of pioglitazone against oxidative and excitotoxic damage. Our results strongly suggest that the neuroprotective effects of PPARγ in peri-infarct brain tissues comprise the concomitant activation of the PI3K/Akt and Nrf2/ARE pathways. Key messages Pioglitazone inhibits apoptosis in ischemic brain tissue.  Pioglitazone acting on PPARγ activates PI3K/Akt pathway in ischemic brain tissue. Pioglitazone activates via Nrf2 the antioxidant defense pathway in injured neurons. Pioglitazone activates the antioxidant response element in neuronal PC12 cells. Pioglitazone fails to protect primary neurons lacking Nrf2 against oxidative damage. Activation of PPARγ supports the survival of viable neurons in peri-infarct regions.

scholarly journals Peripheral Administration of Fetuin-A Attenuates Early Cerebral Ischemic Injury in Rats

2009 ◽  
Vol 30 (3) ◽  
pp. 493-504 ◽  
Author(s):  
Haichao Wang ◽  
Wei Li ◽  
Shu Zhu ◽  
Jianhua Li ◽  
Jason D'Amore ◽  
...  
Keyword(s):  
Cerebral Ischemia ◽  
Brain Tissue ◽  
Immune Cells ◽  
Ischemic Injury ◽  
Dependent Manner ◽  
Ischemic Brain ◽  
Fetuin A ◽  
Ischemic Brain Tissue ◽  
Cerebral Ischemic Injury ◽  
Cerebral Ischemic

Cerebral ischemia-elicited inflammatory responses are driven by inflammatory mediators produced both by central (e.g., neurons and microglia) and infiltrating peripheral immune cells (e.g., macrophage/monocyte), and contribute to the evolution of tissue injury. A ubiquitous molecule, spermine, is released from injured cells, and counter-regulates release of various proinflammatory cytokines. However, the spermine-mediated anti-inflammatory activities are dependent on the availability of fetuin-A, a liver-derived negative acute-phase protein. Using an animal model of focal cerebral ischemia (i.e., permanent middle cerebral artery occlusion, MCAo), we found that levels of fetuin-A in the ischemic brain tissue were elevated in a time-dependent manner, starting between 2 and 6 h, peaking around 24 to 48 h, and returning to baseline 72 h after MCAo. When administered peripherally, exogenous fetuin-A gained entry across the BBB into the ischemic brain tissue, and dose dependently reduced brain infarct volume at 24 h after MCAo. Meanwhile, fetuin-A effectively attenuated (i) ischemia-induced HMGB1 depletion from the ischemic core; (ii) activation of centrally (e.g., microglia) and peripherally derived immune cells (e.g., macrophage/monocytes); and (iii) TNF production in ischemic brain tissue. Taken together, these experimental data suggest that fetuin-A protects against early cerebral ischemic injury partly by attenuating the brain inflammatory response.

Post-ischemic brain tissue alkalosis suppressed by U74006F

1993 ◽  
Vol 114 (1) ◽  
pp. 36-39 ◽  
Author(s):  
Ana M.Q.Vande Linde ◽  
Michael Chopp ◽  
Sue Ann Lee ◽  
Lonni R. Schultz ◽  
K.M.A. Welch
Keyword(s):  
Brain Tissue ◽  
Ischemic Brain ◽  
Ischemic Brain Tissue

scholarly journals Dual Specificity Phosphatase 6 Protects Neural Stem Cells from β-Amyloid-Induced Cytotoxicity through ERK1/2 Inactivation

Biomolecules ◽  
2018 ◽  
Vol 8 (4) ◽  
pp. 181 ◽  
Author(s):  
Wang Liao ◽  
Yuqiu Zheng ◽  
Wenli Fang ◽  
Shaowei Liao ◽  
Ying Xiong ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Stem Cells ◽  
Neural Stem Cells ◽  
Western Blot ◽  
Mitochondrial Dysfunction ◽  
Neuroprotective Effect ◽  
Dependent Manner ◽  
Dual Specificity Phosphatase ◽  
Cell Vitality ◽  
Dual Specificity

Alzheimer’s disease (AD) is a devastating neurodegenerative disease with limited treatment options and no cure. Beta-amyloid (Aβ) is a hallmark of AD that has potent neurotoxicity in neural stem cells (NSCs). Dual specificity phosphatase 6 (DUSP6) is a member of the mitogen-activated protein kinases (MAPKs), which is involved in regulating various physiological and pathological processes. Whether DUSP6 has a protective effect on Aβ-induced NSC injury remains to be explored. C17.2 neural stem cells were transfected with DUSP6-overexpressed plasmid. NSCs with or without DUSP6 overexpression were administrated with Aβ25–35 at various concentrations (i.e., 0, 2.5, 5 μM). DUSP6 expression after Aβ treatment was detected by Real-Time Polymerase Chain Reaction (RT-PCR) and Western blot and cell vitality was examined by the CCK8 assay. The oxidative stress (intracellular reactive oxygen species (ROS) and malondialdehyde (MDA)), endoplasmic reticulum stress (ER calcium level) and mitochondrial dysfunction (cytochrome c homeostasis) were tested. The expression of p-ERK1/2 and ERK1/2 were assayed by Western blot. Our results showed that Aβ decreased the expression of DUSP6 in a dose-dependent manner. The overexpression of DUSP6 increased the cell vitality of NSCs after Aβ treatment. Oxidative stress, ER stress, and mitochondrial dysfunction induced by Aβ could be restored by DUSP6 overexpression. Additionally, the Aβ-induced ERK1/2 activation was reversed. In summary, DUSP6 might have a neuroprotective effect on Aβ-induced cytotoxicity, probably via ERK1/2 activation.

scholarly journals Structure of human dual-specificity phosphatase 7, a potential cancer drug target

2015 ◽  
Vol 71 (6) ◽  
pp. 650-656 ◽  
Author(s):  
George T. Lountos ◽  
Brian P. Austin ◽  
Joseph E. Tropea ◽  
David S. Waugh
Keyword(s):  
Catalytic Domain ◽  
Three Dimensional ◽  
Mitogen Activated Protein Kinase ◽  
Cancer Drug ◽  
Dual Specificity Phosphatase ◽  
Dual Specificity ◽  
Starting Point ◽  
Mitogen Activated Protein ◽  
Dual Specificity Phosphatases

Human dual-specificity phosphatase 7 (DUSP7/Pyst2) is a 320-residue protein that belongs to the mitogen-activated protein kinase phosphatase (MKP) subfamily of dual-specificity phosphatases. Although its precise biological function is still not fully understood, previous reports have demonstrated that DUSP7 is overexpressed in myeloid leukemia and other malignancies. Therefore, there is interest in developing DUSP7 inhibitors as potential therapeutic agents, especially for cancer. Here, the purification, crystallization and structure determination of the catalytic domain of DUSP7 (Ser141–Ser289/C232S) at 1.67 Å resolution are reported. The structure described here provides a starting point for structure-assisted inhibitor-design efforts and adds to the growing knowledge base of three-dimensional structures of the dual-specificity phosphatase family.

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