Osteoarthritis is recognised to be an interactive pathological process involving the cartilage, subchondral bone and synovium. The signals from the synovium play an important role in cartilage metabolism, but little is known regarding the influence of the signalling from bone. Additionally, the collagenases and stromelysin-1 are involved in cartilage catabolism through mitogen-activated protein kinase (MAPK) signalling, but the role of the gelatinases has not been elucidated. Here, we studied the influence of osteoclastic signals on chondrocytes by characterising the expression of interleukin-1β (IL-1β)-induced gelatinases through MAPK signalling. We found that osteoclast-conditioned media attenuated the gelatinase activity in chondrocytes. However, IL-1β induced increased levels of gelatinase activity in the conditioned media group relative to the mono-cultured chondrocyte group. More specifically, IL-1β restored high levels of gelatinase activity in c-Jun N-terminal kinase inhibitor-pretreated chondrocytes in the conditioned media group and led to lower levels of gelatinase activity in extracellular signal-regulated kinase or p38 inhibitor-pretreated chondrocytes. Gene expression generally correlated with protein expression. Taken together, these results show for the first time that signals from osteoclasts can influence gelatinase activity in chondrocytes. Furthermore, these data show that IL-1β restores gelatinase activity through MAPK inhibitors; this information can help to increase the understanding of the gelatinase modulation in articular cartilage.
3T3 Cells ; Animals ; Cartilage, Articular ; cytology ; Cell Survival ; physiology ; Cells, Cultured ; Chondrocytes ; drug effects ; enzymology ; Coculture Techniques ; Culture Media, Conditioned ; Gelatinases ; drug effects ; Interleukin-1beta ; pharmacology ; JNK Mitogen-Activated Protein Kinases ; antagonists & inhibitors ; MAP Kinase Signaling System ; physiology ; Matrix Metalloproteinase 2 ; drug effects ; Matrix Metalloproteinase 9 ; drug effects ; Mice ; Mitogen-Activated Protein Kinases ; antagonists & inhibitors ; drug effects ; Monocytes ; cytology ; NF-kappa B ; antagonists & inhibitors ; Osteoclasts ; physiology ; Protease Inhibitors ; analysis ; Tissue Inhibitor of Metalloproteinase-1 ; drug effects ; Tissue Inhibitor of Metalloproteinase-2 ; drug effects ; p38 Mitogen-Activated Protein Kinases ; antagonists & inhibitors

OBJECTIVETo explore the effects and mechanisms of multi-glycoside of Tripterygium wilfordii (GTW) on improving glomerular inflammatory lesion in rats with diabetic nephropathy (DN).

METHODDN model was induced by unilateral nephrectomy and intraperitoneal injection of STZ (35 mg x kg(-1)) twice. The rats were randomly divided into 3 groups, the sham-operated group (Sham group, n = 5), the vehicle-given group (Vehicle group, n = 5 ) and GTW-treated group (GTW group, n = 5). After the model was successfully established, the rats in GTW group were daily oral administrated with GTW suspension (50 mg x kg(-1) x d(-1)), meanwhile, the rats in Vehicle group were daily oral administrated with distilled water (2 mL) for 8 weeks. From the beginning of the administration, all rats were killed 8 weeks later. Blood and renal tissues were collected,and then UAlb, renal function, glomerular morphology characteristics and glomerular macrophages (ED1 + cells) infiltration, as well as the protein expressions of inflammatory cytokines including tumor necrosis factor(TNF)-α and interleukin(IL)-lβ, and the key molecules in p38MAPK signaling pathway including p38 mitogenactivated protein kinase (MAPK), phosphorylated p38 (p-p38MAPK) and transforming growth factor(TGF)-β1 were investigated respectively.

RESULTGTW not only ameliorated the general state of health and body weight,but also attenuated UAlb, glomerulosclerosis, the infiltration of glomerular ED1 + cells and the protein expressions of TNF-α, IL-1β, p-p38MAPK and TGF-β1 in the kidney in DN model rats.

CONCLUSIONBy means of DN model rats, we demonstrated that GTW has the protective effect on renal inflammatory damage in vivo via inhibiting inflammatory cells infiltration and inflammatory cytokines expression. Furthermore, GTW could improve renal inflammatory lesion through down-regulating the expressions of the key signaling molecules in p38MAPK pathway such as p-p38MAPK and TGF-β1 ,and inhibiting the activation of p38MAPK signaling in the kidney.

Animals ; Diabetic Nephropathies ; drug therapy ; Disease Models, Animal ; Glomerulonephritis ; drug therapy ; Glycosides ; pharmacology ; MAP Kinase Signaling System ; drug effects ; Male ; Rats ; Rats, Sprague-Dawley ; Transforming Growth Factor beta1 ; analysis ; Tripterygium ; chemistry ; p38 Mitogen-Activated Protein Kinases ; physiology

BACKGROUNDTetralogy of Fallot (TOF) is the most common malformation of children with an incidence of approximately 10% of congenital heart disease patients. There can be a wide spectrum to the severity of the anatomic defects, which include ventricular septal defect, aortic override, right ventricular outflow tract obstruction, and right ventricular hypertrophy. We examined the relationship between right ventricular hypertrophy in patients with TOF and the gene expression of factors in the mitogen-activated protein kinase (MAPK) signal pathway.

METHODSTo gain insight into the characteristic gene(s) involved in molecular mechanisms of right ventricular hypertrophy in TOF, differential mRNA and micro RNA expression profiles were assessed using expression-based micro array technology on right ventricular biopsies from young TOF patients who underwent primary correction and on normal heart tissue. We then analyzed the gene expression of the MAPK signal pathway using reverse transcription-polymerase chain reaction (RT-PCR) in normals and TOF patients.

RESULTSUsing the micro RNA chip V3.0 and human whole genome oligonucleotide microarray V1.0 to detect the gene expression, we found 1068 genes showing altered expression of at least two-fold in TOF patients compared to the normal hearts, and 47 micro RNAs that showed a significant difference of at least two-fold in TOF patients. We then analyzed these mRNAs and micro RNAs by target gene predicting software Microcosm Targets version 5.0, and determined those mRNA highly relevant to the right ventricular hypertrophy by RT-PCR method. There were obvious differences in the gene expression of factors in the MAPK signal pathway when using RT-PCR, which was consistent to the results of the cDNA microarray.

CONCLUSIONThe upregulation of genes in the MAPK signal pathway may be the key events that contribute to right ventricular hypertrophy and stunted angiogenesis in patients with TOF.

Child, Preschool ; Humans ; Hypertrophy, Right Ventricular ; genetics ; In Vitro Techniques ; Male ; MicroRNAs ; Mitogen-Activated Protein Kinases ; genetics ; Oligonucleotide Array Sequence Analysis ; RNA, Messenger ; Real-Time Polymerase Chain Reaction ; Reverse Transcriptase Polymerase Chain Reaction ; Signal Transduction ; genetics ; physiology ; Tetralogy of Fallot ; genetics

OBJECTIVESome research has shown that p38 mitogen-activated protein kinase (p38MAPK) plays important roles in lung injuries induced by various factors. Its expression and role in hyperoxia-induced lung injury remains unknown. This study investigated the expression and role of p38MAPK in hyperoxia-induced lung injury juvenile rat model.

METHODSHyperoxia-induced lung injury rat model was prepared by 90% O(2) exposure. The location and expression of p38MAPK in lung tissues were detected by immunohistochemistry and Western blot respectively. Apoptosis index of lung was evaluated by TUNEL technique. The effect of SB203580, a p38MAPK inhibitor, on the apoptosis index of lung was observed.

RESULTSThe expression of phosphor-p38MAPK increased obviously after hyperoxia. Positive phosphor-p38MAPK cells were mainly distributed in the alveolar, airway epithelial cells, pulmonary vascular endothelium cells and infiltrative inflammatory cells. The apoptosis index of lung also significantly elevated. SB203580 inhibited the activation of p38MAPK, and reduced the apoptosis index of lung.

CONCLUSIONSThe phosphor-p38MAPK increased and was expressed in many kinds of lung cells in lung injury rat model. It may play a role in the induction of apoptosis in hyperoxia-induced lung injury.

Animals ; Apoptosis ; Disease Models, Animal ; Female ; Hyperoxia ; complications ; Imidazoles ; therapeutic use ; Immunoblotting ; Lung Injury ; drug therapy ; enzymology ; etiology ; MAP Kinase Signaling System ; Male ; Phosphorylation ; Pyridines ; therapeutic use ; Rats ; Rats, Wistar ; p38 Mitogen-Activated Protein Kinases ; analysis ; physiology

Excessive production of nitric oxide (NO) and proinflammatory cytokines from activated microglia play an important role in human neurodegenerative disorders. Here, we investigated whether celastrol, which has been used as a potent anti-inflammatory and anti-oxidative agent in Chinese medicine, attenuates excessive production of NO and proinflammatory cytokines such as TNF-alpha and IL-1beta in LPS-stimulated BV-2 cells, a mouse microglial cell line. We report here that the LPS-elicited excessive production of NO, TNF-alpha, and IL-1beta in BV-2 cells was largely inhibited in the presence of celastrol, and the attenuation of inducible iNOS and these cytokines resulted from the reduced expression of mRNAs of iNOS and these cytokines, respectively. The molecular mechanisms that underlie celastrol-mediated attenuation were the inhibition of LPS-induced phosphorylation of MAPK/ERK1/2 and the DNA binding activity of NF-kappaB in BV-2 cells. The results indicate that celastrol effectively attenuated NO and proinflammatory cytokine production via the inhibition of ERK1/2 phosphorylation and NF-kappaB activation in LPS-activated microglia. Thus, celastrol may be an effective therapeutic candidate for use in the treatment of neurodegenerative human brain disorders.
Animals ; Cell Line ; Cytokines/*biosynthesis/drug effects ; Gene Expression Regulation, Enzymologic/drug effects/immunology ; Inflammation/immunology ; Inflammation Mediators/immunology ; Mice ; Microglia/*drug effects/immunology ; Mitogen-Activated Protein Kinases/*physiology ; NF-kappa B/metabolism/*physiology ; Nitric Oxide/*metabolism ; Nitric Oxide Synthase Type II/biosynthesis/drug effects ; RNA, Messenger/analysis ; Signal Transduction/*drug effects/physiology ; Transcription, Genetic/drug effects/immunology ; Triterpenes/*pharmacology

Peroxisome proliferator-activated receptor gamma (PPAR-gamma) is a ligand-activated transcription factor and plays an important role in growth, differentiation, and inflammation in different tissues. In this study, we investigated the effects of 15d-PGJ2, a high-affinity ligand of PPAR-gamma, on dedifferentiation and on inflammatory responses such as COX-2 expression and PGE2 production in rabbit articular chondrocytes with a focus on ERK-1/-2, p38 kinase, and PPAR-gamma activation. We report here that 15d-PGJ2 induced dedifferentiation and/or COX-2 expression and subsequent PGE2 production. 15d-PGJ2 treatment stimulated activation of ERK-1/-2, p38 kinase, and PPAR-gamma. Inhibition of ERK-1/-2 with PD98059 recovered 15d-PGJ2-induced dedifferentiation and enhanced PPAR-gamma activation, whereas inhibition of p38 kinase with SB203580 potentiated dedifferentiation and partially blocked PPAR-gamma activation. Inhibition of ERK-1/-2 and p38 kinase abolished 15d-PGJ2-induced COX-2 expression and subsequent PGE2 production. Our findings collectively suggest that ERK-1/-2 and p38 kinase oppositely regulate 15d-PGJ2-induced dedifferentiation through a PPAR-gamma-dependent mechanism, whereas COX-2 expression and PGE2 production is regulated by ERK-1/-2 through a PPAR-gamma-independent mechanism but not p38 kinase in articular chondrocytes. Additionally, these data suggest that targeted modulation of the PPAR-gamma and mitogen-activated protein kinase pathway may offer a novel approach for therapeutic inhibition of joint tissue degradation.
Animals ; Cartilage, Articular/*cytology ; Cell Differentiation/drug effects ; Chondrocytes/cytology/*drug effects/metabolism ; Cyclooxygenase 2/*analysis ; Dinoprostone/biosynthesis ; Mitogen-Activated Protein Kinase 1/*physiology ; Mitogen-Activated Protein Kinase 3/*physiology ; PPAR gamma/*physiology ; Prostaglandin D2/*analogs & derivatives/pharmacology ; Rabbits ; p38 Mitogen-Activated Protein Kinases/*physiology

BACKGROUNDAdvanced oxidation protein products (AOPPs) are new uremic toxins reported by Witko-Sarsat in 1996, which are associated with the pathogenesis of atherosclerosis. However, the mechanisms by which AOPPs enhance atherosclerosis have not been fully understood. Monocyte chemoattractant protein-1 (MCP-1) is a chemokine which stimulates migration of monocytes and plays a critical role in the development of atherosclerosis. In this study, we investigated the effect of AOPPs on MCP-1 expression in cultured vascular smooth muscle cells (VSMCs).

METHODSVSMCs were cultured and then co-incubated with AOPP (200 micromol/L, 400 micromol/L) for different times with or without pretreatment with specific p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580. RT-PCR and Western blott were used to detect MCP-1 mRNA and protein expression at different time points after AOPP stimulation in rat smooth muscle cells. Western blot was used to detect the expression of phosphorylated p38 MAPK.

RESULTSTreatment of VSMC with AOPPs resulted in a significant increase of the expression of MCP-1 mRNA and protein in time- and dose-dependent manner, and could activated p38 MAPK. Pretreatment of VSMCs with SB203580 resulted in a dose-dependent inhibition of AOPPs-induced MCP-1 mRNA and protein expression.

CONCLUSIONSAOPPs can stimulate MCP-1 expression via p38 MAPK in VSMCs. This suggests that AOPPs might contribute to the formation of atherosclerosis through this proinflammatory effect.

Animals ; Atherosclerosis ; etiology ; Cardiovascular Diseases ; etiology ; Cells, Cultured ; Chemokine CCL2 ; genetics ; Enzyme Activation ; Imidazoles ; pharmacology ; Kidney Failure, Chronic ; complications ; Male ; Muscle, Smooth, Vascular ; cytology ; metabolism ; Myocytes, Smooth Muscle ; metabolism ; Oxidation-Reduction ; Proteins ; metabolism ; Pyridines ; pharmacology ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley ; Uremia ; metabolism ; p38 Mitogen-Activated Protein Kinases ; physiology

BACKGROUNDSolar ultraviolet (UV) irradiation induces the production of matrix metalloproteinases (MMPs) by activating cellular signalling transduction pathways. MMPs are responsible for the degradation and/or inhibition of synthesis of collagenous extracellular matrix in connective tissues. We mimicked the action of environmental ultraviolet on skin and investigated the effects of UVB-irradiated human keratinocytes HaCaT and IL-1alpha on mitogen activated protein (MAP) kinase activation, c-Jun and c-Fos (AP-1 is composed of Jun and Fos proteins) mRNA expression and MMP-1 production in UVA-irradiated dermal fibroblasts.

METHODSFollowing UVA irradiation, the culture medium of fibroblasts was replaced by culture medium from UVB-irradiated HaCaT, or replaced by the complete culture medium with interleukin (IL)-1alpha. MAP kinase activity expression in fibroblasts was detected by Western blot. c-Jun and c-Fos mRNA expressions were determined by reverse transcriptional polymerase chain reaction (RT-PCR); MMP-1 production in culture medium was detected by enzyme-linked immunosorbent assay (ELISA).

RESULTSCulture medium from UVB-irradiated keratinocytes increased MAP kinase activity and c-Jun mRNA expression in UVA-irradiated fibroblasts. IL-1alpha increased MAP kinase activity and c-Jun mRNA expression, IL-1alpha also increased c-Fos mRNA expression. Both culture media from UVB-irradiated human keratinocytes and externally applied IL-1alpha increased MMP-1 production in UVA-irradiated fibroblasts.

CONCLUSIONSUVB-irradiated keratinocytes and IL-1alpha indirectly promote MMP-1 production in UVA-irradiated fibroblasts by increasing MAP kinase/AP-1 activity. IL-1 may play an important role in the paracrine activation and dermal collagen excessive degradation leading to skin photoaging.

Cell Line ; Enzyme Activation ; Fibroblasts ; enzymology ; radiation effects ; Humans ; Interleukin-1 ; pharmacology ; Keratinocytes ; physiology ; radiation effects ; Matrix Metalloproteinase 1 ; biosynthesis ; Mitogen-Activated Protein Kinases ; metabolism ; Proto-Oncogene Proteins c-fos ; genetics ; Proto-Oncogene Proteins c-jun ; genetics ; RNA, Messenger ; analysis ; Skin ; radiation effects ; Skin Aging ; Transcription Factor AP-1 ; metabolism ; Ultraviolet Rays

BACKGROUNDPulmonary artery smooth muscle cell (PASMC) proliferation plays an important role in pulmonary vessel structural remodelling. At present, the mechanisms related to proliferation of PASMCs are not clear. Focal adhesion kinase (FAK) is a widely expressed nonreceptor protein tyrosine kinase. Recent research indicates that FAK is implicated in signalling pathways which regulate cytoskeletal organization, adhesion, migration, survival and proliferation of cells. Furthermore, there are no reports about the role of FAK in human pulmonary artery smooth muscle cells (HPASMCs). We investigated whether FAK takes part in the intracellular signalling pathway involved in HPASMCs proliferation and apoptosis, by using antisense oligodeoxynucleotides (ODNs) to selectively suppress the expression of FAK protein.

METHODSCultured HPASMCs stimulated by fibronectin (40 microg/ml) were passively transfected with ODNs, sense FAK, mismatch sense and antisense-FAK respectively. Expression of FAK, Jun NH2-terminal kinase (JNK), cyclin-dependent kinase 2 (CDK 2) and caspase-3 proteins were detected by immunoprecipitation and Western blots. Cell cycle and cell apoptosis were analysed by flow cytometry. In addition, cytoplasmic FAK expression was detected by immunocytochemical staining.

RESULTSWhen compared with mismatch sense group, the protein expressions of FAK, JNK and CDK 2 in HPASMCs decreased in antisense-FAK ODNs group and increased in sense-FAK ODNs group significantly. Caspase-3 expression upregulated in HPASMCs when treated with antisense ODNs and downregulated when treated with sense ODNs. When compared with mismatch sense ODNs group, the proportion of cells at G1 phase decreased significantly in sense ODNs group, while the proportion of cells at S phase increased significantly. In contrast, compared with mismatch sense ODNs group, the proportion of cells at G1 phase was increased significantly in antisense-FAK ODNs group. The level of cell apoptosis in antisense-FAK group was higher than in the mismatch sense group and the latter was higher than sense-FAK group. In addition, the sense-FAK ODNs group was strongly stained by immunocytochemistry, whereas the antisense-FAK ODNs group was weakly stained.

CONCLUSIONSThe results suggest that FAK relates to the proliferation of HPASMCs. Antisense-FAK ODNs inhibit HPASMCs proliferation and facilitate their apoptosis. It is possible that FAK via JNK, CDK 2 signalling pathways enhances HPASMCs proliferation and via caspase-3 inhibits HPASMCs apoptosis.

Apoptosis ; CDC2-CDC28 Kinases ; analysis ; Caspase 3 ; Caspases ; analysis ; Cell Cycle ; Cell Proliferation ; drug effects ; Cells, Cultured ; Cyclin-Dependent Kinase 2 ; Focal Adhesion Kinase 1 ; Focal Adhesion Protein-Tyrosine Kinases ; Humans ; Immunohistochemistry ; JNK Mitogen-Activated Protein Kinases ; analysis ; Muscle, Smooth, Vascular ; cytology ; Myocytes, Smooth Muscle ; physiology ; Oligodeoxyribonucleotides, Antisense ; pharmacology ; Protein-Tyrosine Kinases ; analysis ; physiology ; Pulmonary Artery ; cytology

BACKGROUNDThe severity of hypoalbuminemia has been shown to be related to morbidity and mortality in some critical illnesses, illustrating the need for better understanding of molecular mechanism of hypoalbuminemia. Lipopolysaccharide (LPS) is a key mediator inducing hypoalbuminemia in sepsis and septic shock. The present study was designed to identify if the reduction of albumin expression is directly induced by LPS and modulated by activated extracellular signal-regulated protein kinase (ERK) and p38 mitogen-activated protein kinase (MAPK) in rat hepatocytes.

METHODSPrimary rat hepatocytes were divided into five groups. In two of them, hepatocytes were treated with normal saline or 1 microg/ml LPS, then albumin mRNA expression was observed at 0, 2, 8, 12 and 24 hours after treatment. In another group, hepatocytes were pretreated with 100, 40 or 20 micromol/L of cycloheximide (CHX, an inhibitor of protein synthesis) for 30 minutes followed by 1 microg/ml LPS for 24 hours. Then the RNA was extracted from the cells for RT-PCR to detect the expression of albumin. The other two groups were administered 1 micromol/L, 10 micromol/L and 50 micromol/L of SB203580 (p38 MAPK inhibitor) or PD98059 (ERK inhibitor) 30 minutes prior to 1 microg/ml LPS treatment. After 24 hours of LPS treatment, the supernatant was collected and assayed for albumin concentrations. Data were analyzed by one-way analysis of variance, followed by the Newman-Keul test; a P<0.05 was considered significant.

RESULTSThere was no marked change in albumin mRNA expression in the control group during 24-hours treatment with normal saline. The reduction did not occur until 24 hours after LPS treatment, and albumin mRNA decreased by 30% approximately compared to the control group at 24 hours (0.587 vs 0.832, P=0.007). CHX could inhibit the decline of albumin mRNA induced by LPS and the effect was correlated with the dose of CHX. The ERK inhibitor PD98059 caused a significant increase in LPS-induced albumin production at the three concentrations (119.7, 111.4 and 80.0 ng/ml vs 44.4 ng/ml, P=0.0013, 0.0025 and 0.009, respectively), whereas SB203580 obviously blocked albumin reduction in LPS-treated cells at the concentrations of 10 and 50 micromol/L (87.5 and 93.6 ng/ml vs 44.4 ng/ml, P=0.0076 and 0.0049, respectively).

CONCLUSIONSLPS can induce the reduction of albumin expression by new synthesized proteins indirectly, and the process may be related to the signal proteins of ERK and p38 kinase. The ERK and p38 kinase are critical signaling pathways in LPS-induced hypoalbuminemia which is worthwhile to understand in studying the molecular mechanism of hypoalbuminemia in sepsis and septic shock.

Albumins ; analysis ; genetics ; Animals ; Cycloheximide ; pharmacology ; Extracellular Signal-Regulated MAP Kinases ; physiology ; Gene Expression Regulation ; drug effects ; Hepatocytes ; drug effects ; metabolism ; Lipopolysaccharides ; toxicity ; MAP Kinase Signaling System ; drug effects ; Male ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley ; p38 Mitogen-Activated Protein Kinases ; physiology