IL-10 inhibits cardiac fibroblasts proliferation and phenotype transformation induced by TGF-β1 in rats / 基础医学与临床

Objective To examine the effects of IL-10 on cardiac fibroblasts ( CFBs) proliferation and phenotype transformation to myofibroblasts (MyoFbs) induced by transforming growth factor-β1 (TGF-β1);and to investigate the regulating pathways .Methods Cardiac fibroblasts were isolated from cardiac ventricles of neonatal SD rats . The passage 2~4 were used and divided into the following groups for treatment:1) control group, 2) IL-10 reac-tion group, 3) TGF-β1 reaction group, and 4) IL-10 plus TGF-β1 reaction group (TGF-β1 treatment followed with IL-10 pretreatment ) .Cells proliferation was assessed by MTT assay and immunocytochemistry staining for prolifera-ting cell nuclear antigen (PCNA);the phenotype transformation into MyoFbs was assessed by immunocytochemistry of α-smooth muscle actin (α-SMA);extracellular signal related kinase ( ERK1/2) and P38 kinase pathways were assessed by western-blot.Results TGF-β1 (10 μg/L) treatment boosted the proliferation and the expression ofα-SMA significantly (P<0.01), while IL-10 (10, 50 or 100 μg/L) plus TGF-β1 co-treatment induced lower cell proliferation and expression of α-SMA than treating with TGF-β1 alone ( P<0.05 ) , with the inhibitory effect of IL-10 being concentration dependent .TGF-β1 could significantly stimulate the ERK 1/2 and P38 kinase phospho-rylation ( P<0.01 ) , however IL-10 (100 μg/L) plus TGF-β1 co-treatment failed to down-regulated the phospho-rylation of ERK1/2 and P38 kinase compared with TGF-β1 alone ( ERK1/2:P<0.05;P38:P<0.01 ) .Conclu-sions IL-10 can attenuate TGF-β1-induced CFBs proliferation and phenotype transformation to MyoFbs .The in-hibitory effects may explained by a mechanism of inhibiting the activation of ERK 1/2 and P38 kinase .

Magnolol Inhibits LPS-induced NF-kappaB/Rel Activation by Blocking p38 Kinase in Murine Macrophages

This study demonstrates the ability of magnolol, a hydroxylated biphenyl compound isolated from Magnolia officinalis, to inhibit LPS-induced expression of iNOS gene and activation of NF-kappaB/Rel in RAW 264.7 cells. Immunohisto-chemical staining of iNOS and Western blot analysis showed magnolol to inhibit iNOS gene expression. Reporter gene assay and electrophoretic mobility shift assay showed that magnolol inhibited NF-kappaB/Rel transcriptional activation and DNA binding, respectively. Since p38 is important in the regulation of iNOS gene expression, we investigated the possibility that magnolol to target p38 for its anti-inflammatory effects. A molecular modeling study proposed a binding position for magnolol that targets the ATP binding site of p38 kinase (3GC7). Direct interaction of magnolol and p38 was further confirmed by pull down assay using magnolol conjugated to Sepharose 4B beads. The specific p38 inhibitor SB203580 abrogated the LPS-induced NF-kappaB/Rel activation, whereas the selective MEK-1 inhibitor PD98059 did not affect the NF-kappaB/Rel. Collectively, the results of the series of experiments indicate that magnolol inhibits iNOS gene expression by blocking NF-kappaB/Rel and p38 kinase signaling.

Src Kinase Regulates Nitric Oxide-induced Dedifferentiation and Cyclooxygenase-2 Expression in Articular Chondrocytes via p38 Kinase-dependent Pathway

BACKGROUND: Nitric oxide (NO) in articular chondrocytes regulates dedifferentiation and inflammatory responses by modulating MAP kinases. In this study, we investigated whether the Src kinase in chondrocytes regulates NO-induced dedifferentiation and cyclooxygenase-2 (COX-2) expression. METHODS: Primary chondrocytes were treated with various concentrations of SNP for 24 h. The COX-2 and type II collagen expression levels were determined by immunoblot analysis, and prostaglandin E(2) (PGE(2)) was determined by using a PGE(2) assay kit. Expression and distribution of p-Caveolin and COX-2 in rabbit articular chondrocytes and cartilage explants were determined by immunohistochemical staining and immunocytochemical staining, respectively. RESULTS: SNP treatment stimulated Src kinase activation in a dose-dependent manner in articular chondrocytes. The Src kinase inhibitors PP2 [4-amino-5-(4-chlorophenyl)-7-(t-butyl)pyrazolo(3,4-d)pyrimidine], a significantly blocked SNP-induced p38 kinase and caveolin-1 activation in a dose-dependent manner. Therefore, to determine whether Src kinase activation is associated with dedifferentiation and/or COX-2 expression and PGE(2) production. As expected, PP2 potentiated SNP-stimulated dedifferentiation, but completely blocked both COX-2 expression and PGE2 production. And also, levels of p-Caveolin and COX-2 protein expression were increased in SNP-treated primary chondrocytes and osteoarthritic and rheumatoid arthritic cartilage, suggesting that p-Caveolin may play a role in the inflammatory responses of arthritic cartilage. CONCLUSION: Our previously studies indicated that NO caused dedifferentiation and COX-2 expression is regulated by p38 kinase through caveolin-1 (1). Therefore, our results collectively suggest that Src kinase regulates NO-induced dedifferentiation and COX-2 expression in chondrocytes via p38 kinase in association with caveolin-1.

p38 Kinase Regulates Nitric Oxide-induced Dedifferentiation and Cyclooxygenase-2 Expression of Articular Chondrocytes

BACKGROUND: Caveolin, a family of integral membrane proteins are a principal component of caveolae membranes. In this study, we investigated the effect of p38 kinase on differentiation and on inflammatory responses in sodium nitroprusside (SNP)- treated chondrocytes. METHODS: Rabbit articular chondrocytes were prepared from cartilage slices of 2-week-old New Zealand white rabbits by enzymatic digestion. SNP was used as a nitric oxide (NO) donor. In this experiments measuring SNP dose response, primary chondrocytes were treated with various concentrations of SNP for 24 h. The time course of the SNP response was determined by incubating cells with 1 mM SNP for the indicated time period (0~24 h). The cyclooxygenase-2 (COX-2) and type II collagen expression levels were determined by immunoblot analysis, and prostaglandin E2 (PGE2) assay was used to measure the COX-2 activity. The tyrosine phosphorylation of caveolin-1 was determined by immunoblot analysis and immunostaining. RESULTS: SNP treatment stimulated tyrosine phosphorylation of caveolin-1 and activation of p38 kinase. SNP additionally caused dedifferentiation and inflammatory response. We showed previously that SNP treatment stimulated activation of p38 kinase and ERK-1/-2. Inhibition of p38 kinase with SB203580 reduced caveolin-1 tyrosine phosphorylation and COX-2 expression but enhanced dedifferentiation, whereas inhibition of ERK with PD98059 did not affect caveolin-1 tyrosine phosphorylation levels, suggesting that ERK at least is not related to dedifferentiation and COX-2 expression through caveolin-1 tyrosine phosphorylation. CONCLUSION: Our results indicate that SNP in articular chondrocytes stimulates dedifferentiation and inflammatory response via p38 kinase signaling in association with caveolin-1 phosphorylation.

Ectopic Expression of Caveolin-1 Induces COX-2 Expression in Rabbit Articular Chondrocytes via MAP Kinase Pathway

BACKGROUND: Caveolin-1 is a principal component of caveolae membranes in vivo. Although expression of caveolae structure and expression of caveolin family, caveolin-1, -2 and -3, was known in chondrocytes, the functional role of caveolae and caveolins in chondrocytes remains unknown. In this study, we investigated the role of caveolin-1 in articular chondrocytes. METHODS: Rabbit articular chondrocytes were prepared from cartilage slices of 2-week-old New Zealand white rabbits by enzymatic digestion. Caveolin-1 cDNA was transfected to articular chondrocytes using LipofectaminePLUS. The cyclooxygenase-2 (COX-2) expression levels were determined by immunoblot analysis, immunostaining, immunohistochemistry, and prostaglandin E2 (PGE2) assay was used to measure the COX-2 activity. RESULTS: Ectopic expression of caveolin-1 induced COX-2 expression and activity, as indicated by immunoblot analysis and PGE2 assay. And also, overexpression of caveolin-1 stimulated activation of p38 kinase and ERK-1/ -2. Inhibition of p38 kinase and ERK-1/-2 with SB203580 and PD98059, respectively, led to a dose-dependent decrease COX-2 expression and PGE2 production in caveolin-1-transfected cells. CONCLUSION: Taken together, our data suggest that ectopic expression of caveolin-1 contributes to the expression and activity of COX-2 in articular chondrocytes through MAP kinase pathway.

Activation of Macrophage by PCSC22 Isolated from Poria cocos Sclerotium / 체질인류학회지

The sclerotium of Poria cocos Wolf, which grows on the roots of pine trees, has long been used as a sedative, diuretic, and anti-inflammatory agent. The accumulating data revealed that certain ingredients of the sclerotium of Poria cocos showed anti-tumor activities. Although the mechanism of anti-tumor activity is not known, the polysaccharides may potentiate the host defense mechanism through the activation of immune system. In the present study we show that PCSC22, a polysaccharide isolated from the sclerotium of Poria cocos with one percent sodium carbonate, significantly induces nitric oxide (NO). Immunohistochemical staining of inducible NO synthase (iNOS) showed that the increase of NO was due to the induction of iNOS production. To further study the mechanism responsible for the induction of iNOS gene expression, we investigated the effect of PCSC22 on the activation of p38 kinase, which is important in the gene expression of inflammatory cytokines including iNOS. Western blot assay showed that PCSC22 produced phosphorylation of p38 kinase. In conclusion, we demonstrate that PCSC stimulates macrophages to express iNOS gene through the activation of p38 kinase.