Effects of Glucocorticoid-Induced Transcript 1 Gene Deficiency on Glucocorticoid Activation in Asthmatic Mice / 中华医学杂志(英文版)

Background@#Glucocorticoid (GC) is the first-line therapy for asthma, but some asthmatics are insensitive to it. Glucocorticoid-induced transcript 1 gene (GLCCI1) is reported to be associated with GCs efficiency in asthmatics, while its exact mechanism remains unknown.@*Methods@#A total of 30 asthmatic patients received fluticasone propionate for 12 weeks. Forced expiratory volume in 1 s (FEV) and GLCCI1 expression were detected. Asthma model was constructed in wild-type and GLCCI1 knockout (GLCCI1) mice. Glucocorticoid receptor (GR) and mitogen-activated protein kinase phosphatase 1 (MKP-1) expression were detected by polymerase chain reaction and Western blotting (WB). The phosphorylation of p38 mitogen-activated protein kinase (MAPK) was also detected by WB.@*Results@#In asthmatic patients, the change of FEV was well positively correlated with change of GLCCI1 expression (r = 0.430, P = 0.022). In animal experiment, GR and MKP-1 mRNA levels were significantly decreased in asthmatic mice than in control mice (wild-type: GR: 0.769 vs. 1.000, P = 0.022; MKP-1: 0.493 vs. 1.000, P < 0.001. GLCCI1: GR: 0.629 vs. 1.645, P < 0.001; MKP-1: 0.377 vs. 2.146, P < 0.001). Hydroprednisone treatment significantly increased GR and MKP-1 mRNA expression levels than in asthmatic groups; however, GLCCI1 asthmatic mice had less improvement (wild-type: GR: 1.517 vs. 0.769, P = 0.023; MKP-1: 1.036 vs. 0.493, P = 0.003. GLCCI1: GR: 0.846 vs. 0.629, P = 0.116; MKP-1: 0.475 vs. 0.377, P = 0.388). GLCCI1 asthmatic mice had more obvious phosphorylation of p38 MAPK than wild-type asthmatic mice (9.060 vs. 3.484, P < 0.001). It was still higher even though after hydroprednisone treatment (6.440 vs. 2.630, P < 0.001).@*Conclusions@#GLCCI1 deficiency in asthmatic mice inhibits the activation of GR and MKP-1 and leads to more obvious phosphorylation of p38 MAPK, leading to a decremental sensitivity to GCs.@*Trial Registration@#ChiCTR.org.cn, ChiCTR-RCC-13003634; http://www.chictr.org.cn/showproj.aspx?proj=5926.

Effect of fluoxetine on the depression-like behavior and mitogen-activated protein kinase-p38 signaling pathway in depression rats / 新乡医学院学报

Objective To investigate the effect of fluoxetine on the depression-like behavior and the expression of mitogen-activated protein kinase phosphatase-1 (MKP-1),phosphorylated p38 and p38 in hippocampus of rats with depression,in order to provide clues for the molecular pathological mechanism of depression.Methods Forty Sprague Dawley rats were randomly divided into normal group,depression group,normal saline group and fluoxetine group,with ten rats in each group.The rats in the depression group,normal saline group and fluoxetine group were treated with chronic unpredictable mild stress (CUMS) for eight weeks to prepare the depression models.The rats in the normal saline group and fluoxetine group were treated with normal saline and fluoxetine by intragastric administration respectively from the fifth to eighth week,but the rats in the normal group did not give CUMS and any intervention.The behavior changes of rats in the four groups were evaluated at the time points of before modeling,after modeling and postintervention.The hippocampal tissues of rats were taken after the last the last behavioral evaluations.The expression of MKP-1,p-p38 and p38 protein in hippocampus was detected by Western blot;and the ratio of the expression of p-p38 to p38 protein (p-p38/p38) was calculated.Results There was no significant difference in the behavioral indexes of rats among the four groups (P ＞ 0.05).Compared with pre-modeling,the sucrose preference index decreased,the horizontal movement distance and vertical frequency decreased in the open field test,and the inactivity time of rats in forced swimming test increased in the depression group,normal saline group and fluoxetine group,the differences were statistically significant (P ＜ 0.05).There was no significant difference in the behavioral indexes of rats among the depression group,normal saline group and fluoxetine group (P ＞ 0.05).Compared with the normal group,the sucrose preference index decreased,the horizontal movement distance and vertical frequency of rats in open field test decreased,and the inactivity time of rats in forced swimming test increased in the depression group,normal saline group and fluoxetine group after modeling,the differences were statistically significant(P ＜0.05).Compared with the depression group and normal saline group,the sucrose preference index of rats increased,the horizontal movement distance and vertical frequency of rats in open field test increased,and the inactivity time of rats in forced swimming test shortened in fluoxetine group,the differences were statistically significant (P ＜ 0.05).The expression of MKP-1 in the hippocampus of rats in the depression group and the normal saline group was significantly higher than that in the normal group (P ＜ 0.05).The expression of MKP-1 in the hippocampus of rats in the fluoxetine group was significantly lower than that in the depression group and normal saline group (P ＜ 0.05).There was no significant difference in the expression of MKP-1 in the hippocampus of rats between the depression group and the normal saline group (P ＞ 0.05).There was no significant difference in the expression of MKP-1 in the hippocampus of rats between the fluoxetine group and normal group(P ＞ 0.05).There was no significant difference in the expression of p-p38 and p38 protein and p-p38/p38 in the hippocampus of rats among the four groups (P ＞ 0.05).Conclusions MKP-1 may be associated with the pathogenesis of depression,and p38 may not be the signaling pathway for MKP-1 to take part in the pathogenesis of depression.Fluoxetine may play a role in the treatment of depression by down-regulating MKP-1 expression.MKP-1 may play a key role in the pathogenesis of depression.Fluoxetine may play a role in the treatment of depression by down-regulating.

Effects of enriched environment on behavior and expression of mitogen-activated protein kinase phosphatase-1 in hippocampus of depression rats / 新乡医学院学报

Objective To investigate the effect of enriched environment (EE) on behavior and expression of mitogenactivated protein kinase phosphatase-1 (MKP-1) in hippocampus of depression rats induced by chronic unpredicted mild stress (CUS) and to provide clues for the molecular mechanism of treating depression.Methods Forty Sprague-Dawley rats were randomly divided into control group,CUS group,fluoxetine group and EE group,with 10 rats in each group.The rats in CUS group,fluoxetine group and EE group were given 8 weeks of CUS,and from the fifth week,the rats in EE group and fluoxetine group were given EE and fluoxetine for 4 weeks,respectively.The changes of behavioristic of the rats in the four groups were evaluated by body mass gain,open field test,and sucrose preference.The expression of MKP-1 in hippocampus was detected by Western blot.Results There was no significant difference in body mass,distance of horizontal movement,the number of upright,the times of passing through the grid and sucrose preference index among the four groups(P ＞ 0.05).After modeling,compared with the control group,the body mass gain,distance of horizontal movement,the number of up-right,the times of passing through the grid and sucrose preference index in the CUS group,fluoxetine group and EE group were decreased significantly(P ＜ 0.05);there was no significant difference in the body mass gain,distance of horizontal movement,the number of up-right,the times of passing through the grid and sucrose preference index among the CUS group,fluoxetine group and EE group(P ＞ 0.05).After intervening by fluoxetine and EE,the body mass gain,distance of horizontal movement,the number of up-right,the times of passing through the grid and sucrose preference index in the CUS group were lower than those in the control group(P ＜0.05);but there was no significant difference in the body mass gain,distance of horizontal movement,the number of up-right,the times of passing through the grid and sucrose preference index between the control group and the fluoxetine group and EE group(P ＞ 0.05).Compared with the CUS group,the body mass gain,distance of horizontal movement,the number of up-right,the times of passing through the grid and sucrose preference index in the fluoxetine group and EE group were higher(P ＜ 0.05);there was no significant difference in the body mass gain,distance of horizontal movement,the number of up-right,the times of passing through the grid and sucrose preference index between the fluoxetine group and EE group (P ＞ 0.05).The expression of MKP-1 in hippocampus of CUS group and EE group was higher than that in the control group (P ＜0.05).There was no significant difference in the expression of MKP-1 in hippocampus between the fluoxetine group and control group(P ＞ 0.05).Compared with the CUS group,the expression of MKP-1 in hippocampus in the fluoxetine group decreased (P ＜ 0.05).There was no significant difference in the expression of MKP-1 in hippocampus between the EE group and CUS group(P ＞0.05).Compared with the fluoxetine group,the expression of MKP-1 in hippocampus in the EE group was higher(P ＜ 0.05).Conclusion EE can significantly improve depressive symptoms in rats,but it has no significant effect on MKP-1 protein expression in hippocampus,and EE may not act on depression by affecting MKP-1.

Inhibitory effects of ginsenoside Re on vascular neointimal hyperplasia induced by balloon-injury and ERK signaling in rats / 中国药学杂志

OBJECTIVE: To investigate the inhibitory effect of ginsenoside Re on vascular neointimal hyperplasia induced by balloon-injury and probe its molecular mechanism in rats. METHODS: The rat carotid artery neointimal hyperplasia model was established by rubbing the endothelia with a balloon in male Sprague-Dawley rats, then animals were intrapritoneally injected with distilled water in model group and sham operation group or with ginsenoside Re 6, 12 and 24 mg·kg-1·d-1 in other endothelia rubbed groups. After 14 consecutive days, the injuried artery was taken for H&E staining, the histopathological observation and detecting the neointimal area as well as the ratio of neointimal area/media area were taken to evaluate the vescular intimal hyperplasia level. For probing the molecular mechanism, the expression of mitogen-activated protein kinase phosphatase-1 (MKP-1) was detected at the transcript levels by real time RT-PCR, and the protein expressions of MKP-1 and phosphorylation extracellular signal-regulated kinase 1/2 (pERK12) were examined by immunohistochemistry and analyzed with Image-Pro Plus. RESULTS: Compared with the endothelia rubbing model group, ginsenoside Re 6, 12, 24 mg·kg-1·d-1 medications significantly improved the histopathological changes induced by baloon-injury, decreased the elevated neointimal area and the ratio of neointimal area/media area induced by baloon-injury; ginsenoside Re administration could also down-regulate the elevated pERK1/2 protein expression, and significantly up-regulated the decreased MPK-1 mRNA and protein expressions induced by baloon-injury. CONCLUSION: Ginsenoside Re inhibits the vascular neointimal hyperplasia induced by baloon-injury in rats, the molecular mechanism is related to its inhibition effect on ERK signaling.

Distribution and expression of MKP-1 in the brain of APP/PS1 double-transgenic mice / 解放军医学杂志

Objective To study the distribution and expression of mitogen-activated protein kinase phosphatase-1 (MKP-1) in the brain of APP/PS1 double-transgenic mice for clarifying the relationship between MKP-1 and Alzheimer’s disease (AD). Methods Three, eight and twelve month-old APP/PS1 double-transgenic mice (AD mice) were selected for this study (n=5), and the littermate wild-type male mice were used as normal control (n=5). The distribution and expression of MKP-1 in the brain of mice were assessed by immunohistochemical staining and Western blotting. Results Immunohistochemical staining revealed that MKP-1 was widely expressed in the brain of mice, including the cerebral cortex, hippocampus, and hypothalamus. The number of MKP-1-positive neurons in brains of 3 month-old AD mice (8824 ± 1397) was significant higher than that of 8 month-old mice (5278 ± 1764, P=0.008), and the number of MKP-1-positive neurons in brains of 8 month-old AD mice was significant higher than that of 12 month-old mice (2864 ± 1464, P=0.046). The result of Western blotting was consistent with the result of immunohistochemical staining (F=18.052, P=0.003). Compared with 8 month-old AD mice, the number of MKP-1-positive neurons in brain of littermate wild-type mice (10 121 ± 3657) was higher significantly (P=0.028). MKP-1-positive senile plaques were found in the brains of 8 month-old AD mice, but the number (6.00 ± 4.06) was significant lower than that of 4G8-positive senile plaques (25.60 ± 5.86, P=0.000). Immunofluorescence confocal microscopy revealed the presence of partial co-expression of MKP-1-positive substance and 4G8-positive senile plaques. Conclusion The expression of MKP-1 in the brain of AD mice is down-regulated with age, which may be related to the formation of senile plaques and occurrence of AD.

Effect of dexamethasone on MKP-1 expression in lung tissues in rats with lipopolysaccharide-induced acute lung injury / 中华麻醉学杂志

ObjectiveTo investigate the effect of dexamethasone on mitogen-activated protein kinase phosphatase-1 (MKP-1) expression in lung tissues in rats with lipopolysaccharide (LPS)-induced acute lung injury (ALI).MethodsFifty-four male SD rats weighing 180-230 g were randomly divided into 3 groups:control group (group C,n =6) ;ALI group ( n =24) and dexamethasone group (group D,n =24).LPS 5 mg/kg was injected via tail vein in groups ALI and D,while the equal volume of normal saline was given in group C.Dexamethasone 6 mg/kg was injected intraperitoneally at 30 min before LPS administration in group D.Eight rats in each group were sacrificed at 1 h after normal saline administration (T1) in group C and at 1,3,and 6 h after LPS administration (T1-3 ) in groups ALI and D.The lung tissues were then removed for determination of the expression of phosphorylated p38 mitogen-activated protein kinase (p-p38MAPK) and MKP-1.The concentrations of albumin and TNF-α in bronchoalveolar lavage fluid (BALF) were detected and histopathological changes were observed at T3 ·Another 32 SD rats weighing 180-230 g were randomly divided into 2 groups ( n =16 each):group ALI1 and group D1.The rats were treated as the method mentioned above and the 48 h survival condition was observed.Results Compared with group C, the concentrations of protein and TNF-α in BALF were significantly increased,p-p38MAKP expression was up-regulated at T1.3,and MKP-1 expression was down-regulated at T2,3 in group ALI,and TNF-α concentration in BALF was significantly increased and the expression of p-p38MAKP and MKP-1 was up-regulated at T1-3 in group D ( P ＜ 0.05).Compared with group ALI,the concentrations of protein and TNF-α in BALF were significantly decreased,p-p38MAKP expression was down-regulated and MKP-1 expression was up-reg-ulated at T1-3 ( P ＜ 0.05 ),and the pathological damage was attenuated in group D.The 48 h survival rate was significantly higher in group D1 than in group ALI1 ( P ＜ 0.05).ConclusionThe mechanism by which dexamethasone attenuates the ALI induced by LPS may be related to up-regulation of MKP-1,inhibition of phosphorylation of p38MAPK and decrease in inflammatory response.

Probucol inhibits proliferation of rat aortic smooth muscle cells stimulated with oxidized low-density lipoprotein / 中国病理生理杂志

AIM: To investigate the relationships between antiproliferative mechanisms of probucol and protein expressions of signaling molecules ERK1/2, MKP-1, HO-1 and Trx-1 in rat aortic smooth muscle cells (RASMCs) stimulated with ox-LDL. METHODS: The effects of probucol on cell cycle, cell proliferation and the expressions of ERK1/2, MKP-1, HO-1 and Trx-1 in the presence of ox-LDL were observed by means of MTT test, FCM and Western blotting. RESULTS: (1) Probucol significantly inhibited the proliferation of RASMCs stimulated with ox-LDL. A value in 100 μmol/L probucol+35 mg/L ox-LDL group was reduced by 34.9% as compared to ox-LDL group (P<0.01). (2) Probucol protected against ox-LDL-induced RASMCs proliferation through inducing cell growth arrest at G_0/G_1 phase and cell apoptosis. (3) ox-LDL increased the expression of p-ERK1/2 by 34.7% (P<0.01) and decreased MKP-1 by 60.0% (P<0.01), respectively, as compared to control. Probucol attenuated the increase in ox-LDL-stimulated p-ERK1/2 level by 15.7%, but increased MKP-1 expression by 2 times (P<0.01). (4)ox-LDL at concentration of 35 mg/L decreased the intracellular Trx-1 expression by 28.9% (P<0.05), and slightly increased the level of HO-1 expression as compared to control (P<0.05). Probucol enhanced the expression of Trx-1 by 91.6% (P<0.01) and HO-1 by 31.9% (P<0.01), respectively as compared to ox-LDL group. CONCLUSION: Probucol inhibits ox-LDL-stimulated the proliferation of RASMCs through increases in MKP-1/HO-1 expression, suppression of cell cycle progression and induction of cell apoptosis.

Triptolide Inhibits the Proliferation of Immortalized HT22 Hippocampal Cells Via Persistent Activation of Extracellular Signal-Regulated Kinase-1/2 by Down-Regulating Mitogen-Activated Protein Kinase Phosphatase-1 Expression

OBJECTIVE: Triptolide (TP) has been reported to suppress the expression of mitogen-activated protein kinase (MAPK) phosphatase-1 (MKP-1), of which main function is to inactivate the extracellular signal-regulated kinase-1/2 (ERK-1/2), the p38 MAPK and the c-Jun N-terminal kinase-1/2 (JNK-1/2), and to exert antiproliferative and pro-apoptotic activities. However, the mechanisms underlying antiproliferative and pro-apoptotic activities of TP are not fully understood. The purpose of this study was to examine whether the down-regulation of MKP-1 expression by TP would account for antiproliferative activity of TP in immortalized HT22 hippocampal cells. METHODS: MKP-1 expression and MAPK phosphorylation were analyzed by Western blot. Cell proliferation was assessed by 3H-thymidine incorporation. Small interfering RNA (siRNA) against MKP-1, vanadate (a phosphatase inhibitor), U0126 (a specific inhibitor for ERK-1/2), SB203580 (a specific inhibitor for p38 MAPK), and SP600125 (a specific inhibitor for JNK-1/2) were employed to evaluate a possible mechanism of antiproliferative action of TP. RESULTS: At its non-cytotoxic dose, TP suppressed MKP-1 expression, reduced cell growth, and induced persistent ERK-1/2 activation. Similar growth inhibition and ERK-1/2 activation were observed when MKP-1 expression was blocked by MKP-1 siRNA and its activity was inhibited by vanadate. The antiproliferative effects of TP, MKP-1 siRNA, and vanadate were significantly abolished by U0126, but not by SB203580 or SP600125. CONCLUSION: Our findings suggest that TP inhibits the growth of immortalized HT22 hippocampal cells via persistent ERK-1/2 activation by suppressing MKP-1 expression. Additionally, this study provides evidence supporting that MKP-1 may play an important role in regulation of neuronal cell growth.