To clone human mitogen-activated protein kinase kinase 6 (MKK6) gene promoter and explore its transcription activity by ubiquitin specific peptidase 22 (USP22).
 Methods: MKK6 gene promoter was amplified by PCR and two bases mutation within USP22 binding site was subsequently introduced. The wild type and mutant MKK6 promoter were inserted into the luciferase report vector pGL3-Basic, respectively. Recombinant plasmids were co-transfected with plasmid pRL-TK into HeLa cells, and the luciferase activities were measured by dual luciferase reporter system. Furthermore, the direct interaction between USP22 and MKK6 promoter was detected by chromatin immunoprecipitation (ChIP) assay. Finally, the MKK6 transcription activity was measured after knockdown of USP22.
 Results: The recombinant luciferase report vectors containing wild or mutant type of MKK6 promoter were successfully constructed. Mutation of USP22 binding site resulted in decrease of MKK6 promoter-driven luciferase activity in HeLa cells (P<0.05). USP22 could interact directly with MKK6 promoter. Down-regulation of USP22 led to the decreased MKK6 mRNA expression (P<0.05).
 Conclusion: USP22 could regulate the transcription activity of MKK6 gene in HeLa cells.
HeLa Cells ; Humans ; Luciferases ; MAP Kinase Kinase 6 ; Promoter Regions, Genetic ; Thiolester Hydrolases ; metabolism ; Transcription, Genetic

OBJECTIVETo study the effects of 50 Hz power-frequency magnetic fields on signal transduction pathway of P38 mitogen-activated protein kinase (P38 MAPK), and explore the cellular signal transduction mechanism of the biological effects induced by power-frequency magnetic fields.

METHODSChinese hamster lung (CHL) cell line was exposed to power-frequency magnetic fields with two intensities(0.1 and 0.4 mT) for different exposure durations. The cytoplasmic protein was extracted. The phosphorylated(activated) and non-phosphorylated P38 MAPK and MKK3/MKK6 were measured by Western blotting analysis with their specific corresponding antibodies.

RESULTSPower-frequency magnetic fields at 0.4 mT for 10 min could transitorily induce the activation of P38 MAPK and after 15 min the phosphorylation of P38 MAPK restored to control level, while 0.1 mT power-frequency magnetic fields could not induce the activation of P38 MAPK within 24 h. However, both 0.1 mT and 0.4 mT power-frequency magnetic fields could not phosphorylate(activate) the MKK3/MKK6, which is a general upstream kinase of P38 MAPK.

CONCLUSIONPower-frequency magnetic fields could transitorily activate the P38 MAPK, but not MKK3/MKK6. The activation mechanism of P38 MAPK needs to be further identified.

Animals ; Cell Line ; Cricetinae ; Cricetulus ; Enzyme Activation ; radiation effects ; Lung ; enzymology ; radiation effects ; MAP Kinase Kinase 3 ; metabolism ; MAP Kinase Kinase 6 ; metabolism ; Magnetics ; p38 Mitogen-Activated Protein Kinases ; metabolism ; radiation effects

OBJECTIVETo quantify the interleukin (IL)-1beta mRNA and IL-6 mRNA expression induced by lipopolysaccharides ([PS) extracted from Porphyromonoas endodontalis (P. endodontalis) in osteoblasts, and to relate P. endodontalis LPS to the bone resorptive pathogenesis in the lesions of chronic apical periodontitis.

METHODSMG63 cells was pretreated with PD98059 or SB203580 for 1 h and then treated with P. endodontolis LPS for 6 h. The expression of IL-1beta mRNA and IL-6 mRNA were detected by reverse transcription polymerase chain reaction (RT-PCR) technique.

RESULTSThe production of IL-1beta mRNA induced by P. endodontalis LPS decreased in osteoblasts pretreated with PD98059. Both of the production of IL-1beta mRNA and JL-6 mRNA induced by P. endodontalis LPS decreased in osteoblasts pretreated with SB203580.

CONCLUSIONThe synthesis of IL-1beta mRNA stimulated by Pendodontalis LPS in MG63 probably occur via extracellular signal-regulated kinase (ERK) 1/2 and p38 mitogen activated protein kinase (MAPK) signal transduction system. The synthesis of IL-6 mRNA stimulated by P.endodontalis LPS in MG63 probahly occur via p38MAPK signal transduction system.

Humans ; Imidazoles ; Interleukin-6 ; Lipopolysaccharides ; MAP Kinase Signaling System ; Osteoblasts ; Porphyromonas endodontalis ; Pyridines ; RNA, Messenger ; Signal Transduction ; p38 Mitogen-Activated Protein Kinases

The aim of the present study was to investigate the role of mitogen-activated protein kinase kinase 6 (MKK6)-P38 signaling pathway in cyclic mechanical stretch-induced high mobility group box 1 protein (HMGB1) expression in alveolar macrophages. In the study, Sprague-Dawley rats were anesthetized and then sacrificed by bloodletting. The lungs were lavaged six times with prechilled PBS. Alveolar macrophages were isolated from lavage samples. Recombinant plasmids were transfected into alveolar macrophages with liposome DOTAP. Alveolar macrophages transfected with P38(AF)/pGFP and MKK6b(E)/pGFP plasmids were taken as treated groups, while the groups that transfected with pcDNA3 plasmid and pGFP plasmid served as blank transfection group and control group, respectively. All the groups were then cultured in 6-well Bioflex cell culture plates and exposed to cyclic mechanical stretch at 20% elongation using Flexercell 4000T cell stretching unit. The results showed that the transfection of MKK6b(E) led to a marked increases in P38 kinase activity compared with control group. In contrast, the transfection of P38(AF) significantly inhibited P38 kinase activity. Compared with control group, HMGB1 protein and mRNA expression in MKK6b(E) transfected cells increased markedly, while HMGB1 expression in P38(AF) transfected cells decreased markedly. These results suggest that MKK6-P38 MAPK signaling pathway regulates the expression of HMGB1 induced by cyclic mechanical stretch in alveolar macrophages.
Animals ; Cells, Cultured ; HMGB1 Protein ; metabolism ; MAP Kinase Kinase 6 ; metabolism ; Macrophages, Alveolar ; enzymology ; Phosphorylation ; Rats ; Rats, Sprague-Dawley ; Signal Transduction ; Stress, Mechanical ; p38 Mitogen-Activated Protein Kinases ; metabolism

Objective: To investigate the therapeutic effect and mechanism of Liangge Powder against sepsis-induced acute lung injury (ALI) . Methods: From April to December 2021, the key components of Liangge Powder and its targets against sepsis-induced ALI were analyzed by network pharmacology, and to enrich for relevant signaling pathways. A total of 90 male Sprague-Dawley rats were randomly assigned to sham-operated group, sepsis-induced ALI model group (model group), Liangge Powder low, medium and high dose group, ten rats in the sham-operated group and 20 rats in each of the remaining four groups. Sepsis-induced ALI model was established by cecal ligation and puncture. Sham-operated group: gavage with 2 ml saline and no surgical treatment. Model group: surgery was performed and 2 ml saline was gavaged. Liangge Powder low, medium and high dose groups: surgery and gavage of Liangge Powder 3.9, 7.8 and 15.6 g/kg, respectively. To measure the wet/dry mass ratio of rats lung tissue and evaluate the permeability of alveolar capillary barrier. Lung tissue were stained with hematoxylin and eosin for histomorphological analysis. The levels of tumor necrosis factor-alpha (TNF-α), interleukin (IL) -6 and IL-1β in bronchoalveolar lavage fluid (BALF) were measured by enzyme-linked immunosorbent assay. The relative protein expression levels of p-phosphatidylinositol 3-kinase (PI3K), p-protein kinase B (AKT), and p-ertracellular regulated protein kinases (ERK) were detected via Western blot analysis. Results: Network pharmacology analysis indicated that 177 active compounds of Liangge Powder were selected. A total of 88 potential targets of Liangge Powder on sepsis-induced ALI were identified. 354 GO terms of Liangge Powder on sepsis-induced ALI and 108 pathways were identified using GO and KEGG analysis. PI3K/AKT signaling pathway was recognized to play an important role for Liangge Powder against sepsis-induced ALI. Compared with the sham-operated group, the lung tissue wet/dry weight ratio of rats in the model group (6.35±0.95) was increased (P<0.001). HE staining showed the destruction of normal structure of lung tissue. The levels of IL-6 [ (392.36±66.83) pg/ml], IL-1β [ (137.11±26.83) pg/ml] and TNF-α [ (238.34±59.36) pg/ml] were increased in the BALF (P<0.001, =0.001, <0.001), and the expression levels of p-PI3K, p-AKT and p-ERK1/2 proteins (1.04±0.15, 0.51±0.04, 2.31±0.41) were increased in lung tissue (P=0.002, 0.003, 0.005). The lung histopathological changes were reduced in each dose group of Liangge Powder compared with the model group. Compared with the model group, the wet/dry weight ratio of lung tissue (4.29±1.26) was reduced in the Liangge Powder medium dose group (P=0.019). TNF-α level [ (147.85±39.05) pg/ml] was reduced (P=0.022), and the relative protein expression levels of p-PI3K (0.37±0.18) and p-ERK1/2 (1.36±0.07) were reduced (P=0.008, 0.017). The wet/dry weight ratio of lung tissue (4.16±0.66) was reduced in the high-dose group (P=0.003). Levels of IL-6, IL-1β and TNF-α[ (187.98±53.28) pg/ml, (92.45±25.39) pg/ml, (129.77±55.94) pg/ml] were reduced (P=0.001, 0.027, 0.018), and relative protein expression levels of p-PI3K, p-AKT and p-ERK1/2 (0.65±0.05, 0.31±0.08, 1.30±0.12) were reduced (P=0.013, 0.018, 0.015) . Conclusion: Liangge Powder has therapeutic effects in rats with sepsis-induced ALI, and the mechanism may be related to the inhibition of ERK1/2 and PI3K/AKT pathway activation in lung tissue.
Male ; Animals ; Rats ; Rats, Sprague-Dawley ; Proto-Oncogene Proteins c-akt ; Phosphatidylinositol 3-Kinase ; Phosphatidylinositol 3-Kinases ; Powders ; Animal Experimentation ; Interleukin-6 ; MAP Kinase Signaling System ; Network Pharmacology ; Tumor Necrosis Factor-alpha ; Acute Lung Injury/drug therapy* ; Sepsis/drug therapy*

AIM: (-)-Epigallocatechin-3-gallate (EGCG), a major compound of tea polyphenols, exhibited antitumor activity in previous studies. In these studies, EGCG usually inhibits EGFR, and impairs the ERK1/2 phosphorylation in tumor cells. The aim was to clarify the mechanism of ERK1/2 activation induced by EGCG. METHOD: Jurkat and 293T cells were treated with EGCG in different culture conditions. Western Blotting (WB) was employed to analyze ERK1/2 and MEK phosphorylation. Cetuximab and FR180204 were used to inhibit cell signaling. The stability of EGCG was assessed by HPLC. The concentration of hydrogen peroxide generated by the auto-oxidation of EGCG was determined by photocolorimetric analysis. RESULTS: Activation of ERK1/2 was observed to be both time-and dose-dependent. Stimulation of cell signaling was dependent on MEK activity, but independent of EGFR activity. Unexpectedly, EGCG was depleted within one hour of incubation under traditional culture conditions. Auto-oxidation of EGCG generated a high level of hydrogen peroxide in the medium. Addition of catalase and SOD to the acidic medium inhibited the oxidation of EGCG. However, this particular condition also prevented the phosphorylation of ERK1/2. The generation of ROS by hydrogen peroxide may also induce ERK1/2 activation in Jurkat cells. CONCLUSION ERK1/2 phosphorylation was caused by auto-oxidation of EGCG. Traditional culture conditions were determined to be inappropriate for EGCG research.
Camellia sinensis ; chemistry ; Catalase ; metabolism ; Catechin ; analogs & derivatives ; pharmacology ; Humans ; Hydrogen Peroxide ; metabolism ; Jurkat Cells ; MAP Kinase Signaling System ; drug effects ; Mitogen-Activated Protein Kinase 3 ; metabolism ; Mitogen-Activated Protein Kinase 6 ; metabolism ; Oxidation-Reduction ; Phosphorylation ; Plant Extracts ; pharmacology ; Polyphenols ; pharmacology ; Superoxide Dismutase ; metabolism

BACKGROUND: p38 and extracellular signal-regulated kinase (ERK) mitogen-activated protein kinase (MAPK) signaling are thought to have critical role in lipopolysaccharide (LPS)-induced immune response but the molecular mechanism underlying the induction of these signaling are not clear. METHODS: Specific inhibitors for p38, SB203580, and for ERK, PD98059 were used. Cells were stimulated by LPS with or without specific MAPK inhibitors. RESULTS: LPS activated inducible nitric oxide synthase (iNOS), subsequent NO productions, and pro-inflammatory cytokine gene expressions (TNF-alpha, IL-1beta, IL-6, and IL-12). Treatment of both SB203580 and PD98059 decreased LPS-induced NO productions. Concomitant decreases in the expression of iNOS mRNA and protein were detected. SB203580 and PD98059 decreased LPS-induced gene expression of IL-1beta and IL-6. SB203580 increased LPS-induced expression of TNF-alpha and IL-12, and reactive oxygen species production, but PD98059 had no effect. CONCLUSION: These results indicate that both p38 and ERK pathways are involved in LPS-stimulated NO synthesis, and expression of IL-1beta and IL-6. p38 signaling pathways are involved in LPS-induced TNF-alpha and IL-12, and reactive oxygen species plays an important role in these signaling in macrophage.
Gene Expression ; Interleukin-12 ; Interleukin-6 ; Macrophages ; MAP Kinase Signaling System ; Nitric Oxide Synthase Type II ; Nitric Oxide* ; Phosphotransferases* ; Protein Kinases* ; Reactive Oxygen Species ; RNA, Messenger ; Tumor Necrosis Factor-alpha

Endothelial dysfunction induced by intermittent hypoxia (IH) participates in obstructive sleep apnea syndrome (OSAS)-associated cardiovascular disorders. Myeloid differentiation primary response 88 (MyD88) and tumor necrosis factor receptor-associated factor 6 (TRAF6) regulate numerous downstream adaptors like mitogen-activated protein kinases (MAPKs) and the subsequent oxidative stress and inflammatory responses. This study aimed to characterize the role of MyD88/TRAF6 in IH-treated cell function and its associated signaling. Human umbilical vein endothelial cells (HUVECs) were randomly exposed to IH or normoxia for 0, 2, 4 and 6 h. Western blotting was used to detect the expression pattern of target gene proteins [angiotensin 1 receptor (AT1R), p-ERK1/2, p-p38MAPK, MyD88 and TRAF6], and the relationships among these target genes down-regulated by the corresponding inhibitors were studied. Finally, the influence of these target genes on proliferation of HUVECs was also assessed by EdU analysis. Protein levels of AT1R, TRAF6 and p-ERK1/2 were increased after IH exposure, with a slight rise in MyD88 and a dynamic change in p-p38MAPK. The down-regulation of TRAF6 by siRNA reduced ERK1/2 phosphorylation during IH without any effects on AT1R. Blockade of AT1R with valsartan decreased TRAF6 and p-ERK1/2 protein expression after IH exposure. ERK1/2 inhibition with PD98059 suppressed only AT1R expression. IH promoted HUVECs proliferation, which was significantly suppressed by the inhibition of TRAF6, AT1R and ERK1/2. The findings demonstrate that TRAF6 regulates the proliferation of HUVECs exposed to short-term IH by modulating cell signaling involving ERK1/2 downstream of AT1R. Targeting the AT1R-TRAF6-p-ERK1/2 signaling pathway might be helpful in restoring endothelial function.
Cell Hypoxia ; Cell Proliferation ; Cells, Cultured ; Gene Expression Regulation ; Human Umbilical Vein Endothelial Cells ; physiology ; Humans ; MAP Kinase Signaling System ; drug effects ; Phosphorylation ; Receptor, Angiotensin, Type 1 ; genetics ; metabolism ; TNF Receptor-Associated Factor 6 ; genetics ; metabolism ; Valsartan ; pharmacology

Interleukin-6 (IL-6) is an important cytokine that participates in inflammation reaction and cell growth and differentiation in the immune and nervous systems. However, the neuroprotection of IL-6 against N-methyl-D-aspartate (NMDA)-induced neurotoxicity and the related underlying mechanisms are still not identified. In the present study, the cultured cerebellar granule neurons (CGNs) from postnatal (8-day) infant rats were chronically exposed to IL-6 for 8 d, and then NMDA (100 micromol/L) was applied to the cultured CGNs for 30 min. Methyl-thiazole-tetrazolium (MTT) assay, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) method and confocal laser scanning microscope (CLSM) were used to detect neuronal vitality, apoptosis and dynamic changes of intracellular Ca(2+) levels in the neurons, respectively. Anti-gp130 monoclonal antibody (75 ng/mL) was employed to the cultured CGNs with IL-6 to inhibit IL-6 activity so as to evaluate the role of gp130 (a 130 kDa glucoprotein transducing IL-6 signal) in mediating IL-6 neuroprotection. Western blot was used to measure the expressions of phospho-signal transducer and activator of transcription 3 (STAT3) and phospho-extracellular signal regulated kinase 1/2 (ERK1/2) in the cultured CGNs. The NMDA stimulation of the cultured CGNs without IL-6 pretreatment resulted in a significant reduction of the neuronal vitality, notable enhancement of the neuronal apoptosis and intracellular Ca(2+) overload in the neurons. The NMDA stimulation of the CGNs chronically pretreated with IL-6 caused a remarkable increase in the neuronal vitality, marked suppression of neuronal apoptosis and intracellular Ca(2+) overload in the neurons, compared with that in the control neurons without IL-6 pretreatment. Furthermore, anti-gp130 antibody blocked the inhibitory effect of IL-6 on NMDA-induced intracellular Ca(2+) overload in the neurons. The levels of phospho-STAT3 and phospho-ERK1/2 were significantly higher in IL-6-pretreated CGNs than those in IL-6-untreated neurons. The results suggest that chronic IL-6 pretreatment of CGNs protects the neurons against NMDA-induced neurotoxicity. The neuroprotective effect of IL-6 is closely related to its suppression of NMDA-induced intracellular Ca(2+) overload and is possibly mediated by gp130/JAK-STAT3 and gp130/RAS-ERK1/2 transduction pathways.
Animals ; Animals, Newborn ; Cells, Cultured ; Cerebellum ; cytology ; drug effects ; metabolism ; Interleukin-6 ; physiology ; MAP Kinase Signaling System ; N-Methylaspartate ; antagonists & inhibitors ; toxicity ; Neurons ; cytology ; drug effects ; metabolism ; Neuroprotective Agents ; Rats ; Rats, Sprague-Dawley ; STAT3 Transcription Factor ; metabolism

The present study explored the anti-inflammatory and anti-thrombotic mechanism of Jingfang Granules on tail thrombosis induced by carrageenan in mice. Thirty-two male ICR mice were randomly divided into a control group, a model group, a Jingfang Granules group, and a positive drug(aspirin) group, with eight mice in each group. The thrombosis model was induced by intraperitoneal injection of carrageenan(45 mg·kg~(-1)) combined with low-temperature stimulation, and the mice were treated with drugs for 7 days before modeling. Twenty-four hours after modeling, blood was detected for four blood coagulation indices in each group. The enzyme-linked immunosorbent assay(ELISA) was used to detect the activity of plasma interleukin-6(IL-6), interleukin-1β(IL-1β), tumor necrosis factor-α(TNF-α), and other inflammatory factors. The tails of mice in each group were cut off to observe tail lesions and measure the length of the thrombus. The protein expression and phosphorylation level of extracellular signal-regulated kinase 1/2(ERK1/2) and p38 mitogen-activated protein kinase(p38 MAPK) in spleen tissues were detected by Western blot. The results showed that dark red thrombus appeared in the tails of mice in each group. The length of the black part accounted for about 40% of the total tail in the model group. Additionally, the model group showed prolonged prothrombin time(PT), increased fibrinogen(FIB) content, and shortened activated partial thromboplastin time(APTT). Compared with the model group, the groups with drug intervention displayed shortened black parts in the tail and improved four blood coagulation indices(P<0.05). As revealed by ELISA, the expression levels of TNF-α, IL-1β, and IL-6 in the mouse plasma were significantly up-regulated in the model group, and those in the groups with drug intervention were reduced as compared with the model group(P<0.05). As demonstrated by Western blot, the protein expression and phosphorylation levels of ERK1/2 and p38 MAPK in the spleen tissues were significantly elevated in the model group, while those in the Jingfang Granules group were down-regulated as compared with the model group with a significant difference. Jingfang Granules can inhibit tail thrombosis of mice caused by carrageenan presumedly by inhibiting the activation of ERK1/2 and p38 MAPK signaling pathways.
Animals ; Carrageenan/adverse effects* ; Interleukin-6/metabolism* ; MAP Kinase Signaling System ; Male ; Mice ; Mice, Inbred ICR ; Signal Transduction ; Thrombosis/drug therapy* ; Tumor Necrosis Factor-alpha/metabolism* ; p38 Mitogen-Activated Protein Kinases/metabolism*