The role of the inhibition of glutathione-S-transferase in the protective mechanisms of ischemic postconditioning

2013 ◽  
Vol 91 (8) ◽  
pp. 625-632 ◽  
Author(s):  
Borbála Balatonyi ◽  
Balázs Gasz ◽  
Viktória Kovács ◽  
János Lantos ◽  
Gábor Jancsó ◽  
...  

The antioxidant glutathione-S-transferase (GST) is a crucial determinant of the development of ischaemic−reperfusion (I/R) injury, and plays a pivotal role in the regulation of the mitogen activated protein kinase (MAPK) pathways involved in stress response and apoptosis. The aim of this study was to investigate whether inhibition of GST can abolish the benefit of ischaemic postconditioning (IPoC). A neonatal rat cardiomyocyte cell culture was prepared and divided into 6 groups: (I) control group without treatment; (II) cells exposed to simulated I/R; (III) simulated I/R (sI/R) with IPoC; (IV) ethacrynic acid (EA) alone; (V) sI/R with EA; and (VI) sI/R and IPoC together with EA. Viability of the cells was measured by MTT assay, the quantity of apoptotic cells was assessed by flow cytometry following annexin V-FITC − propidium-iodide double staining. The activation of JNK, p38, ERK/p42-p44 MAPKs, and GSK-3β protein kinase was determined by flow-cytometric assay. GST inhibition markedly increased the apoptosis and decreased the cell viability despite IPoC. The protective effect of IPoC was lost in GST-inhibited groups for all MAPKs and GSK-3β. GST activity is required for the survival of cultured cardiomyocytes under stress conditions. GST inhibition was associated with differential activation of MAP and the protein kinases regulating these pathways in the process of ischaemic postconditioning.

2020 ◽  
Vol 150 (7) ◽  
pp. 1731-1737
Author(s):  
Qi Xu ◽  
Ziyu Chen ◽  
Borong Zhu ◽  
Gaorui Wang ◽  
Qi Jia ◽  
...  

ABSTRACT Background Parkinson's disease (PD) is a common neurodegenerative disorder. Cinnamon procyanidin oligomers (CPOs) are flavonoids with many claimed health benefits. Objective This study aimed to elucidate the neuroprotection of A-type CPOs (CPO-A) and the underlying mechanisms in cultured cell and animal models of PD. Methods Thirty male mice (C57BL/6, 9-wk old) were assigned to 3 groups (n = 10), and were given daily gavage of saline [control and 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) groups] or CPO-A (150 mg/kg, CPO-A group) during days 1–15 and daily intraperitoneal injections of saline (control group) or MPTP (20 mg/kg; MPTP and MPTP + CPO-A groups) during days 11–15. After the motor behavior test, all mice were killed on day 16 to collect the substantia nigra (SN) for assaying the neuroprotective effects of CPO-A. SH-SY5Y cells were treated with 12.5 μM CPO-A for 2 h or 3 activators of stress-related kinases (5–25 μM) for 12–48 h followed by 1 mM 1-methyl-4-phenylpyridinium (MPP+) for assays of viability, morphology, and stress status. Results Compared with the control, the MPTP treatment decreased (P < 0.05) locomotor activity by 21%, and tyrosine hydroxylase (TH) positive neurons by 55% and Th mRNA concentration by 51% in the SN. The CPO-A treatment attenuated or restored (P < 0.05) these changes and inhibited (P < 0.05) the MPTP-induced activation of P38 mitogen-activated protein kinase (P38MAPK) and P53, along with the downstream expression of BCL-2 associated X protein (BAX) in the SN. In SH-SY5Y cells, the CPO-A treatment blocked (P < 0.01) the MPP+-induced accumulation of intracellular reactive oxygen species and neurotoxicity. However, this protection was abolished (P < 0.05) by activators of the P38MAPK/P53/BAX pathway. Conclusion CPO-A protected against MPP+-induced cytotoxicity in SH-SY5Y cells and MPTP-induced neurotoxicity in mice by regulating the P38MAPK/P53/BAX signaling. Our findings reveal a novel role and mechanism of a food flavonoid CPO-A in preventing neurodegeneration.


2019 ◽  
Vol 97 (12) ◽  
pp. 1159-1168
Author(s):  
Fatma F. Ali ◽  
Walaa Yehia Abdelzaher ◽  
Randa Ahmed Ibrahim ◽  
Doaa Mohamed Elroby Ali

Although heme oxygenase-1 (HO-1) is part of an endogenous defense system implicated in the homeostatic response, its role in cell proliferation and tumor progression is still controversial. Endometrial hyperplasia (EH) is associated with high risk of endometrial cancer (EC). Therefore, we aimed to evaluate the effect of hemin, a HO-1 inducer, against EH. Thirty-two female rats (60–70 days old) were divided into 4 groups treated for 1 week: vehicle control group, hemin group (25 mg/kg; i.p. 3 times/week), estradiol valerate (EV) group (2 mg/kg per day, p.o.), and hemin plus EV group. Sera were obtained for reduced glutathione level. Uterine malondialdehyde, superoxide dismutase, total nitrite/nitrate, and interleukin-1β levels were estimated. HO-1 and p38 mitogen-activated protein kinase expressions were obtained in uterine tissue. Uterine histological and immunohistochemical assessment of iNOS and Ki67 were also done. Results demonstrated that upregulation of HO-1 expression in hemin plus EV rats led to amelioration of EH which was confirmed with histological examination. This was associated with significant decrease in oxidative stress parameters, p38 mitogen-activated protein kinase expression, and interleukin-1β level. Also, uterine iNOS and Ki67 expressions were markedly suppressed. In conclusion, upregulation of HO-1 expression via hemin has ameliorative effect against EH through its antioxidant, anti-inflammatory, and antiproliferative actions.


2009 ◽  
Vol 29 (5) ◽  
pp. 873-885 ◽  
Author(s):  
Heng Zhao

Ischemic postconditioning initially referred to a stuttering reperfusion performed immediately after reperfusion, for preventing ischemia/reperfusion injury in both myocardial and cerebral infarction. It has evolved into a concept that can be induced by a broad range of stimuli or triggers, and may even be performed as late as 6 h after focal ischemia and 2 days after transient global ischemia. The concept is thought to be derived from ischemic preconditioning or partial/gradual reperfusion, but in fact the first experiment for postconditioning was carried out much earlier than that of preconditioning or partial/gradual reperfusion, in the research on myocardial ischemia. This review first examines the protective effects and parameters of postconditioning in various cerebral ischemic models. Thereafter, it provides insights into the protective mechanisms of postconditioning associated with reperfusion injury and the Akt, mitogen-activated protein kinase (MAPK), protein kinase C (PKC), and ATP-sensitive K+ (KATP) channel cell signaling pathways. Finally, some open issues and future challenges regarding clinical translation of postconditioning are discussed.


1996 ◽  
Vol 317 (1) ◽  
pp. 109-118 ◽  
Author(s):  
Angela CLERK ◽  
Judith GILLESPIE-BROWN ◽  
Stephen J. FULLER ◽  
Peter H. SUGDEN

In ventricular myocytes cultured from neonatal rat hearts, bradykinin (BK), kallidin or BK(1–8) [(Des-Arg9)BK] stimulated PtdInsP2 hydrolysis by 3–4-fold. EC50 values were 6 nM (BK), 2 nM (kallidin), and 14 μM [BK(1–8)]. BK or kallidin stimulated the rapid (less than 30 s) translocation of more than 80% of the novel protein kinase C (PKC) isoforms nPKC-Δ and nPKC-ϵ from the soluble to the particulate fraction. EC50 values for nPKC-Δ translocation by BK or kallidin were 10 and 2 nM respectively. EC50 values for nPKC-ϵ translocation by BK or kallidin were 2 and 0.6 nM respectively. EC50 values for the translocation of nPKC-Δ and nPKC-ϵ by BK(1–8) were more than 5 μM. The classical PKC, cPKC-α, and the atypical PKC, aPKC-ζ, did not translocate. BK caused activation and phosphorylation of p42-mitogen-activated protein kinase (MAPK) (maximal at 3–5 min, 30–35% of p42-MAPK phosphorylated). p44-MAPK was similarly activated. EC50 values for p42/p44-MAPK activation by BK were less than 1 nM whereas values for BK(1–8) were more than 10 μM. The order of potency [BK≈kallidin ≫ BK(1–8)] for the stimulation of PtdInsP2 hydrolysis, nPKC-Δ and nPKC-ϵ translocation, and p42/p44-MAPK activities suggests involvement of the B2 BK receptor subtype. In addition, stimulation of all three processes by BK was inhibited by the B2 BK receptor-selective antagonist HOE140 but not by the B1-selective antagonist Leu8BK(1–8). Exposure of cells to phorbol 12-myristate 13-acetate for 24 h inhibited subsequent activation of p42/p44-MAPK by BK suggesting participation of nPKC (and possibly cPKC) isoforms in the activation process. Thus, like hypertrophic agents such as endothelin-1 (ET-1) and phenylephrine (PE), BK activates PtdInsP2 hydrolysis, translocates nPKC-Δ and nPKC-ϵ, and activates p42/p44-MAPK. However, in comparison with ET-1 and PE, BK was only weakly hypertrophic as assessed by cell morphology and patterns of gene expression. This difference could not be attributed to dissimilarities between the duration of activation of p42/p44-MAPK by BK or ET-1. Thus activation of these signalling pathways alone may be insufficient to induce a powerful hypertrophic response.


2000 ◽  
Vol 350 (3) ◽  
pp. 891-899 ◽  
Author(s):  
Anu PUNN ◽  
James W. MOCKRIDGE ◽  
Saleha FAROOQUI ◽  
Michael S. MARBER ◽  
Richard J. HEADS

Delayed cytoprotection (preconditioning) occurs 24h after sublethal simulated ischaemia and reperfusion (SI/R) in neonatal rat ventricular cardiomyocytes. SI/R was used to investigate the role of activation of mitogen-activated protein kinases (MAPKs), stress-activated protein kinases (SAPKs) and phosphoinositide 3-kinase-dependent protein kinase B (PKB)/Akt in cytoprotection. SI resulted in transient dual (Thr/Tyr) phosphorylation of p42/p44-MAPK and p38-MAPK, weak phosphorylation of p46/p54-SAPK, but no phosphorylation of PKB. ‘Reperfusion’ caused further transient phosphorylation of p38-MAPK, but sustained phosphorylation of p42/p44-MAPK (lasting 4h) and of Ser473 of PKB (lasting 2h). Furthermore, SI/R (24h) induced delayed protection against lethal SI, as determined by an increase in cell viability {bioreduction of MTT [3-(4,5-dimethylthiazolyl-2)-2,5-diphenyltetrazolium bromide]} and a decrease in cell injury (release of creatine kinase). Both protection and phosphorylation of p42/p44-MAPK were blocked by the MEK-1/2 (MAPK/Erk kinase-1/2) inhibitor PD98059 (50µM) when given during SI/R, but not when given during SI alone. The p38-MAPK inhibitor SB203580 (10µM) blocked the p38-MAPK-dependent phosphorylation of activating transcription factor 2 in vitro, and the phosphoinositide 3-kinase inhibitor wortmannin (100nM) blocked PKB phosphorylation on Ser473. However, neither SB203580 nor wortmannin had any effect on delayed protection. Therefore sustained activation of p42/p44-MAPK during simulated ‘reperfusion’ following sublethal SI mediates preconditioning in cardiomyocytes independently of transient activation of p38-MAPK or sustained activation of PKB.


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