Mitogen-activated protein kinases(MAPKs)are Ser/Thr kinases consisting of extracellular regulated protein kinases(ERK)1/2,c-Jun N-terminal kinase 1/2/3,p38 isoforms(α,β,γ,and δ),and ERK5,which mediate a range of cellular activities including proliferation,differentiation,apoptosis,immunity,and inflammation. Pain sensitization is a remodeling mechanism of central and peripheral nociceptor. A growing number of evidences have indicated that MAPKs are extensively activated in the spinal dorsal cord and dorsal root ganglions in the animal models of diabetic neuropathic pain(DNP)and play an important role in the central and peripheral sensitization of DNP. In addition,some drugs can alleviate DNP by suppressing MAPKs activation of central and peripheral nervous system. This article summarizes the research progress of MAPKs in central and peripheral sensitization of DNP.
Animals ; Diabetic Neuropathies ; Ganglia, Spinal ; Mitogen-Activated Protein Kinases ; Neuralgia ; p38 Mitogen-Activated Protein Kinases

No abstract available.
Collagen ; Fibroblasts ; Gene Expression ; p38 Mitogen-Activated Protein Kinases

ABSTRACT Methanolic extract from the leaves of Acanthus ilicifolius L. (A. ilicifolius L.) is a potent inhibitor of Candida albicans (C. albicans) growth and anti-inflammatory. C. albicans causes oral candidiasis in immunosuppressive condition. Mitogen-activated protein kinase (MAPK) signalling via p38 appears to discriminate between yeast and hyphal cells of C. albicans. Activation of p38 MAPK by hyphae results in the upregulation of proinflammatory cytokines. The p38 MAPK activation is known to impair corticosteroid action. The research was conducted to investigate the effect of methanolic extract A. ilicifolius L. treatment of oral candidiasis with the immunosuppressive condition through enhancement of p38 MAPK expression in the epithelial cells. Immunosuppressed conditions were obtained when 16 healthy male Rattus norvergicus (Wistar) was given oral administration of dexamethasone and tetracycline for 14 days and induced with C. albicans (ATCC-10231) 1 McFarland. The subjects were divided into four groups (n = 4/group): immunosuppression (IS), immunosuppression with oral candidiasis without treatment (ISC), immunosuppression with oral candidiasis and nystatin treatment (ISC+N), and immunosuppression with oral candidiasis and A. ilicifolius L. treatment (ISC+AI), and were treated for 14 days. Later, the rats were euthanised, and their tongue were biopsied. The p38 MAPK expression was subjected to immunohistochemical examination, observed under a microscope (400× magnification) and statistically analysed (one-way ANOVA, LSD-test, p < 0.05). The p38 MAPK expression of ISC+AI (36.05 ± 1.54) was higher than IS (26 ± 2.32), ISC (26.4 ± 3.71), IS+N (34.2 ± 0.99). Significant differences existed between ISC+AI and ISC+N to IS and ISC (p < 0.05). No significant differences were present between IS and ISC; ISC+AI and ISC+N (p > 0.05). Therefore, this treatment could enhance p38 MAPK expression in oral candidiasis with the immunosuppressed condition.
Acanthaceae ; Candidiasis, Oral ; Immunosuppression Therapy ; p38 Mitogen-Activated Protein Kinases

The induction of interleukin-6 (IL-6) using combined proinflammatory agents (LPS/IFN-gamma or TNF-alpha/IFN-gamma) was studied in relation to p38 mitogen-activated protein kinase (MAPK) and NF-kappaB transcriptional factor in primary neonatal cardiomyocytes. When added to cultures of cardiomyocytes, the combined agents (LPS/IFN-gamma or TNF-alpha/IFN-gamma) had stimulatory effect on the production of IL-6 and the elevation was significantly reduced by SB203580, a specific p38 MAPK inhibitor. SB203580 inhibited protein production and gene expression of IL-6 in a concentration-dependent manner. In this study, IFN-gamma enhancement of TNF-alpha-induced NF-kappaB binding affinity as well as p38 MAP kinase activation was observed. However, a specific inhibitor of p38 MAPK, SB203580, had no effect on TNF-alpha/IFN-gamma or LPS/IFN-gamma-induced NF-kappaB activation. This study strongly suggests that these pathways about TNF-alpha/IFN-gamma or LPS/IFN-gamma-activated IL-6 release can be primarily dissociated in primary neonatal cardiomyocytes.
Gene Expression ; Interleukin-6* ; Myocytes, Cardiac* ; NF-kappa B ; p38 Mitogen-Activated Protein Kinases ; Protein Kinases*

BACKGROUNDMesangial hypercellularity is a critical early histopathological finding in human and experimental glomerular diseases. Hyperlipidemia and the glomerular deposition of lipoproteins are commonly associated with mesangial hypercellularity and play an important pathobiological role in the development of glomerular diseases. The activated cytoplasmic mitogen-activated protein kinase (MAPK), including mainly extracellular-signal regulated protein kinase (ERK), c-Jun amino-terminal kinase (JNK), and p38, has been thought to translocate into the nucleus and activate various transcription factors and protooncogenes associated with cell growth and proliferation. Lipoprotein (a) (Lp(a)) has been shown to stimulate proliferation of mesangial cells, but the events of Lp(a) signaling have not yet been characterized. The purpose of this study was to investigate the signal transduction pathways involved in Lp(a)-induced cell proliferation and provide an evidence for the participation of Lp(a) in intracellular signaling pathways for mesangial cell proliferation.

METHODSLp(a) was isolated from a patient who was being treated with low density lipoprotein (LDL)-apheresis by density gradient ultracentrifugation and then chromatography. Human mesangial cells (HMCs) were isolated by the sequential sieving technique and stimulated with Lp(a) in different concentration and time course. The DNA synthesis of the cells was measured by [3H] thymidine incorporation for detecting the proliferation. The expression of all the three members of MAPK family, including ERK1/ERK2, JNK, and p38, and their phosphorylation were detected by Western blotting.

RESULTSLp(a) could induce a significant dose-dependent proliferation of HMCs. The 3H-TdR incorporation was 1.64+/-0.31, 1.69+/-0.48, 3.59+/-0.68 (P<0.01), 4.14+/-0.78 (P<0.01), and 4.05+/-0.55 (P<0.01) (10(3) cpm) at the Lp(a) concentration of 0, 5, 10, 25, and 50 microg/ml, respectively. Lp(a) induced an increase in ERK1/ERK2 phosphorylation between 5 and 60 minutes, and in JNK phosphorylation between 15 and 30 minutes after incubating with HMCs, whereas the level of p38 and its phosphorylation was not changed.

CONCLUSIONSLp(a) could stimulate the proliferation of HMCs by activiating the phosphorylation of ERK1/ERK2 and JNK MAPK signaling pathway, whereas p38 pathway had no effect on the Lp(a)-induced HMC proliferation, which indicated that three MAPKs seem to be distinctly involved in the effect. In particular, it also provides the evidence that Lp(a) may act as one of the major endogenous modulators for mitogenic signaling response and cell proliferation within the glomerulus.

Blotting, Western ; Cells, Cultured ; Humans ; JNK Mitogen-Activated Protein Kinases ; metabolism ; Lipoprotein(a) ; pharmacology ; Mesangial Cells ; Mitogen-Activated Protein Kinase 1 ; metabolism ; Mitogen-Activated Protein Kinase 3 ; metabolism ; Phosphorylation ; drug effects ; p38 Mitogen-Activated Protein Kinases ; metabolism

Mitogen-activated protein kinases (MAPKs) play critical regulatory roles in the production of the pro-inflammatory cytokines and downstream signaling events which lead to inflammation. Inflammation is a primarily localized and protective response of host against microbial infection. Controlled inflammation is beneficial and necessary for host defense while uncontrolled inflammatory response results in inflammatory diseases such as septic shock, rheumatoid arthritis and cancer. The MAPK family consists of three subfamilies; the extracellular signal-regulated kinases (ERKs), the c-Jun N-terminal kinases (JNKs), and the p38 MAPKs. MAPKs are involved in transmitting extracellular signals to nucleus which leads to gene regulation. In this review, we summarize the current knowledge of ERK1/2, JNKs, and p38 MAPK members and their roles in inflammation.
Arthritis, Rheumatoid ; Cytokines ; Extracellular Signal-Regulated MAP Kinases ; Humans ; Inflammation ; Mitogen-Activated Protein Kinases ; p38 Mitogen-Activated Protein Kinases ; Phosphotransferases ; Shock, Septic

We investigated the question of whether 7-oxygenated cholesterol derivatives could affect inflammatory and/or immune responses in atherosclerosis by examining their effects on expression of IL-23 in monocytic cells. 7alpha-Hydroxycholesterol (7alphaOHChol) induced transcription of the TLR6 gene and elevated the level of cell surface TLR6 protein in THP-1 monocytic cells. Addition of an agonist of TLR6, FSL-1, to TLR6-expressing cells by treatment with 7alphaOHChol resulted in enhanced production of IL-23 and transcription of genes encoding the IL-23 subunit alpha (p19) and the IL-12 subunit beta (p40). However, treatment with 7-ketocholesterol (7K) and 7beta-hydroxycholesterol (7betaOHChol) did not affect TLR6 expression, and addition of FSL-1 to cells treated with either 7K or 7betaOHChol did not influence transcription of the genes. Pharmacological inhibition of ERK, Akt, or PI3K resulted in attenuated transcription of TLR6 induced by 7alphaOHChol as well as secretion of IL-23 enhanced by 7alphaOHChol plus FSL-1. Inhibition of p38 MAPK or JNK resulted in attenuated secretion of IL-23. These results indicate that a certain type of 7-oxygenated cholesterol like 7alphaOHChol can elicit TLR6-mediated expression of IL-23 by monocytic cells via PI3K/Akt and MAPKs pathways.
Atherosclerosis ; Cholesterol ; Interleukin-12 ; Interleukin-23* ; Macrophages ; p38 Mitogen-Activated Protein Kinases ; Toll-Like Receptor 6

Cultured cortical primary astroglia treated with zinc died while rapidly detached from culture plates, a distinct part of zinc-treated astroglia. In the present study, we investigated the mechanism underlying the rapid change in the morphologic integrity of zinc-treated astroglia. Among the early cellular events occurring in zinc-treated astroglia, strong activation of p38 MAPK and JNK was evident. Although inhibitors of p38 (SB203580 and SB202190) or JNK (SP600125) did not protect zinc-insulted astroglia from cell death, the p38 inhibitors, but not the JNK inhibitor, suppressed actin filament and cell morphology disruption. The Ca2+ ionophore, A23187, also suppressed actin filament and cell morphology disruption, but not cell death, of zinc-insulted astroglia. However, A23187 did not inhibit p38 MAPK activation in zinc-treated astroglia. Together these results suggest that zinc influx in astroglia results in rapid loss of the morphologic integrity via mechanisms regulated by p38 kinase and/or Ca2+ signaling.
Actin Cytoskeleton ; Astrocytes ; Calcimycin ; Cell Death ; p38 Mitogen-Activated Protein Kinases ; Phosphotransferases ; Zinc

OBJECTIVETo investigate the effect of cyclic stretch on p38 mitogen-activated protein kinase (p38MAPK) signaling pathway during stretch-induced differentiation process of C2C12 myoblasts.

METHODSC2C12 cells were seeded on Bio Flex 6-well plates, and cells were subsequently subjected to cyclic stretch at an optimal magnitude (10%) and frequency (0.5 Hz). The effects of cyclic stretch were examined at 2, 6, 12, 24 h. Antibodies specific to p38MAPK phosphorylated forms and the total protein levels of the p38MAPK were examined using Western blot analysis.

RESULTSThese results indicated that p38MAPK was activated during stretch-induced C2C12 cell differentiation. The level of phosphorylated protein was higher in the p38MAPK signaling pathway. The expression of total protein was maintained at baseline level. There were no significant differences between groups. Treatment of cells with specific p38MAPK inhibitor SB203580 could decrease the expression of myogenin, but not completely abolish the myogenin expression after stretch.

CONCLUSIONp38MAPK signaling pathway plays an important role during stretch-induced differentiation process of C2C12 myoblasts, but is not activated exclusively in this process.

Cell Differentiation ; Humans ; Imidazoles ; Myoblasts ; Phosphorylation ; Pyridines ; Signal Transduction ; p38 Mitogen-Activated Protein Kinases

5-Lipoxygenase (5-LO) plays a pivotal role in the progression of atherosclerosis. Therefore, this study investigated the molecular mechanisms involved in 5-LO expression on monocytes induced by LPS. Stimulation of THP-1 monocytes with LPS (0~3 microg/ml) increased 5-LO promoter activity and 5-LO protein expression in a concentration-dependent manner. LPS-induced 5-LO expression was blocked by pharmacological inhibition of the Akt pathway, but not by inhibitors of MAPK pathways including the ERK, JNK, and p38 MAPK pathways. In line with these results, LPS increased the phosphorylation of Akt, suggesting a role for the Akt pathway in LPS-induced 5-LO expression. In a promoter activity assay conducted to identify transcription factors, both Sp1 and NF-kappaB were found to play central roles in 5-LO expression in LPS-treated monocytes. The LPS-enhanced activities of Sp1 and NF-kappaB were attenuated by an Akt inhibitor. Moreover, the LPS-enhanced phosphorylation of Akt was significantly attenuated in cells pretreated with an anti-TLR4 antibody. Taken together, 5-LO expression in LPS-stimulated monocytes is regulated at the transcriptional level via TLR4/Akt-mediated activations of Sp1 and NF-kappaB pathways in monocytes.
Arachidonate 5-Lipoxygenase ; Atherosclerosis ; Monocytes* ; NF-kappa B ; p38 Mitogen-Activated Protein Kinases ; Phosphorylation ; Transcription Factors