Regulating effect of N-acetyl-seryl-aspartyl-lysyl-proline on activation of c-jun N-terminal kinase pathway in rats with silicosis / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the regulatory effect of N-acetyl-seryl-aspartyl-lysyl-proline (AcSDKP) on the activation of c-jun N-terminal kinase (JNK) signal transduction pathway and its role in silicotic fibrosis.</p><p><b>METHODS</b>A rat model of silicosis was developed by intratracheal instillation. Sixty rats were randomly divided into 4-week control group (n = 10), 8-week control group (n = 10), 4-week silicosis model group (n = 10), 8-week silicosis model group (n = 10), AcSDKP treatment group (n = 10), and AcSDKP prevention group (n = 10). The content of hydroxyproline in lung tissue was measured using a p-dimethylaminoben-zaldehyde reagent; the expression levels of transforming growth factor (TGF)-beta 1 (TGF-β1), phospho-JNK, JNK, and c-jun in lung tissue were measured by Western blot. The lung fibroblasts from neonatal rats were cultured, and the 4th generation of cells were used in the experiment; these cells were divided into control group, TGF-β1 stimulation group, SP600125 intervention group, and AcSDKP intervention group. The distributions of phospho-JNK and c-jun in lung fibroblasts were observed by immunocytochemistry; the expression levels of type I collagen and type III collagen in lung fibroblasts were measured by Western blot.</p><p><b>RESULTS</b>The expression levels of TGF-β1, phospho-JNK, and c-jun and the content of hydroxyproline in the AcSDKP treatment group were 70.60%, 78.03%, 79.85%, and 71.28%, respectively, of those in the 4-week silicosis model group (P < 0.05) and 77.99%, 66.73%, 69.94%, and 64.82%, respectively, of those in the 8-week silicosis model group (P < 0.05); the expression levels of TGF-β1, phospho-JNK, and c-jun and the content of hydroxyproline in the AcSDKP prevention group were 84.56%, 61.18%, 64.73%, and 74.96%, respectively, of those in the 8-week silicosis model group (P < 0.05). The expression levels of phospho-JNK and c-jun in the AcSDKP intervention group were 54.59% and 55.56%, respectively, of those in the TGF-β1 stimulation group; the expression levels of type I collagen and type III collagen in the AcSDKP intervention group were 79.9% and 84.4%, respectively, of those in the TGF-β1 stimulation group (P < 0.05).</p><p><b>CONCLUSION</b>AcSDKP exerts anti-silicotic fibrosis effect probably by inhibiting the activation of JNK signal transduction pathway mediated by TGF-β1 and the deposition of interstitial collagen.</p>

Effect of N-acetyl-seryl-aspartyl-lysyl-proline on differentiation from pulmonary fibroblast to myofibroblast mediated by Rho-associated coiled-coil forming protein kinase pathway / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate whether N-acetyl-seryl-aspartyl-lysyl-proline (Ac-SDKP) can inhibit the differentiation of pulmonary fibroblasts into myofibroblasts by regulating Rho-associated coiled-coil forming protein kinase (ROCK) pathway mediated by transforming growth factor-β1 (TGF-β1).</p><p><b>METHODS</b>Primary culture of pulmonary fibroblasts was performed by trypsinization method. Four generations of pulmonary fibroblasts were divided into control group, TGF-β-induced differentiation group, Y-27632 treatment group, and Ac-SDKP treatment group. The intracellular distributions of ROCK, serum response factor (SRF), and α-smooth muscle actin (α-SMA) were observed by confocal laser scanning microscopy. The protein expression of ROCK, SFR, α-SMA, and type I and type III collagen in pulmonary fibroblasts was measured by Western blot. The mRNA expression of ROCK, SFR, and α-SMA was measured by real-time quantitative PCR.</p><p><b>RESULTS</b>Compared with the control group, the pulmonary fibroblasts stimulated by TGF-β1 had a lot of α-SMA antibody-labeled myofilaments in parallel or cross arrangement, as observed by confocal laser scanning microscopy, and the mRNA and protein expression of ROCK, SRF, and α-SMA and protein expression of type I and type III collagen increased significantly after 6, 12, and 24 h of stimulation (P < 0.05). Compared with the TGF-β1-induced differentiation group, the Y-27632 treatment group and Ac-SDKP treatment group had significantly decreased mRNA and protein expression of ROCK, SRF, and α-SMA and protein expression of type I and type III collagen at the same time point (P < 0.05).</p><p><b>CONCLUSION</b>Ac-SDKP can inhibit the differentiation of pulmonary fibroblasts into myofibroblasts and the synthesis of collagen in rats by regulating the ROCK pathway mediated by TGF-β1. That may be one of the mechanisms by which Ac-SDKP acts against (silicotic) pulmonary fibrosis.</p>

AcSDKP attenuates PDGF-induced cardiac fibroblasts proliferation and collagen expression: role of extracellular regulated protein kinase 1/2 pathway / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the effects of AcSDKP on platelet-derived growth factor (PDGF)-induced rat cardiac fibroblasts proliferation and collagen expression and explore the role of extracellular regulated protein kinase 1/2 (ERK1/2) pathway on this process.</p><p><b>METHODS</b>Metabolic activity of fibroblasts was determined by CCK-8. Cell cycle was detected by flow cytometry. Expressions of type I and type III collagen were measured by immunocytochemistry and Western blot. Expressions of phospho-ERK1/2 and ERK1/2 were detected by Western blot.</p><p><b>RESULT</b>10(-9) mol/L AcSDKP could significantly inhibit PDGF-induced cardiac fibroblasts proliferation, collagen expression and expressions of phospho-ERK1/2, while the protein levels of ERK1/2 were not significantly affected by AcSDKP.</p><p><b>CONCLUSION</b>AcSDKP could inhibit PDGF-induced cardiac fibroblasts proliferation and collagen expression through activation of phosphor-ERK1/2 pathway.</p>

Effect of AcSDKP on the proliferation and collagen synthesis in cultured rat cardiac fibroblasts stimulated by PDGF / 中国应用生理学杂志

<p><b>AIM</b>To investigate whether AcSDKP can inhibit proliferation and collagen synthesis in cultured rat cardiac fibroblasts mediated by PDGF.</p><p><b>METHODS</b>Neonatal rat cardiac fibroblasts were isolated. The cell proliferation was observed by 3H-proline incorporation assay.</p><p><b>RESULTS</b>On the culture of 0.4% FBS, PDGF stimulated cardiac fibroblasts proliferation and collagen synthesis with a dose-dependent manner at the concentrations from 1 ng/ml to 20 ng/ml, in which 10 ng/ml PDGF reached its peak. AcSDKP at the concentration from 10(-10) mol/L to 10(-8) mol/L could inhibit cardiac fibroblasts proliferation and collagen synthesis mediated by PDGF. 10(-9) mol/L AcSDKP attained its peak on inhibiting cardiac fibroblasts proliferation and collagen synthesis.</p><p><b>CONCLUSION</b>AcSDKP can inhibit proliferation and collagen synthesis in cultured rat cardiac fibroblasts mediated by PDGF.</p>

Role of AcSDKP on collagen synthesis and degradation in cultured rat cardiac fibroblast / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the role of AcSDKP on collagen synthesis and degradation in cultured rat cardiac fibroblasts.</p><p><b>METHODS</b>Neonatal rat cardiac fibroblasts were isolated and stimulated by PDGF. The cell proliferation was observed by (3)H-TdR incorporation assay. The synthesis of collagen was measured by (3)H-proline incorporation assay. The expression of type I and type III collagen and MMP-1 protein were measured by Western blot. The MMP-2 and MMP-9 activity was evaluated with zymography assay.</p><p><b>RESULTS</b>PDGF stimulated cardiac fibroblasts proliferation with increased collagen synthesis and type I and type III collagen protein expressions as well as MMP-2 and MMP-9 activities and MMP-1 expression. AcSDKP inhibited cardiac fibroblasts proliferation induced by PDGF and reduced collagen synthesis and type I and type III collagen protein expression. AcSDKP also further up-regulated MMP-2 and MMP-9 activities and MMP-1 expression in cardiac fibroblasts induced by PDGF.</p><p><b>CONCLUSION</b>AcSDKP inhibited proliferation and collagen synthesis and up-regulated matrix metalloproteinases activity or expression induced by PDGF, which was possibly related with the effect of AcSDKP anti-fibrosis.</p>