Combined expression of CTGF and tissue inhibitor of metalloprotease-1 promotes synthesis of proteoglycan and collagen type II in rhesus monkey lumbar intervertebral disc cells in vitro

Background Low back pain has emerged as a widespread disease often caused by intervertebral disc degeneration.This study aimed to establish an in vitro cell culture model of rhesus monkey lumbar intervertebral discs and to investigate the effect of combined connective tissue growth factor （CTGF） and tissue inhibitor of metalloprotease-1（TIMP-1） expression mediated by adeno-associated virus （AAV） on collagen type Ⅱ and proteoglycan levels.The purpose of these investigations was to explore potential methods for relieving the degeneration of lumbar intervertebral disc cells.Methods Rhesus monkey lumbar intervertebral disc nucleus pulposus cells （NPCs） were isolated by enzyme digestion,cultured, and transduced with rAAV2-CTGF-IRES-TIMP-1, rAAV2-CTGF, or rAAV2-TIMP-1 at a multiplicity of infection （MOl） of 106.The expression of collagen type Ⅱ and proteoglycan was measured using RT-PCR and Western blotting.The synthetic rate of proteoglycan was measured using 35S incorporation.Results Rhesus monkey lumbar intervertebral disc NPCs were transduced with rAAV2-CTGF-IRES-TIMP-1,rAAV2-CTGF, and rAAV2-TIMP-1 and the transduced genes were expressed and detected.Compared to the control,CTGF promoted the synthesis of collagen type Ⅱ and proteoglycan.TIMP-1 showed an enhancing effect on the expression of proteoglycan but no effect on collagen type Ⅱ.Expression of both genes in rhesus monkey lumbar intervertebral disc NPCs significantly enhances the synthesis of proteoglycan and collagen type Ⅱ.Conclusions Single gene transduction of CTGF or TIMP-1 can enhanced synthesis of proteoglycan.CTGF expression can also enhance collagen type Ⅱ protein synthesis.Combined transduction of both CTGF and TIMP1 can significantly promote the expression of proteoglycan and collagen type Ⅱ to levels greater than transduction of a single gene alone.Our study provides a good basis for multi-gene therapy to treat lumbar intervertebral disc degeneration.     

Increased expression and activity of MMP-9 in C-reactive protein- induced human THP-1 mononuclear cells is related to activation of nuclear factor kappa-B

The relation between the expression and activity of MMP-9 in C-reactive protein （CRP）-induced human THP-1 mononuclear cells and the activation of nuclear factor kappa-B （NF-κB） was studied to investigate the possible role of CRP in plaque destabilization. Human THP-1 cells were incubated in the presence of CRP at 0 （control group）, 25, 50 and 100 μg/mL （CRP groups） for 24 h. In PDTC （a specific NF-κB inhibitor） group, the cells were pre-treated with PDTC at 10 μmol/L and then with 100 μg/mL CRP. The conditioned media （CM） and human THP-1 cells in different groups were harvested. MMP-9 expression in CM and human THP-1 cells was measured by ELISA and Western blotting. MMP-9 activity was assessed by fluorogenic substrates. The expression of NF-κB inhibitor α （IκB-α） and NF-κB p65 was detected by Western blotting and ELISA respectively. The results showed that CRP increased the expression and activity of MMP-9 in a dose-dependent manner in the human THP-1 cells. Western blotting revealed that IiB-α expression was decreased in the cells with the concentrations of CRP and ELISA demonstrated that NF-κB p65 expression in the CRP-induced cells was increased. After pre-treatment of the cells with PDTC at 10 μmol/L, the decrease in IκB-α expression and the increase in NF-κB p65 expression in the CRP-induced cells were inhibited, and the expression and activity of MMP-9 were lowered too. It is concluded that increased expression and activity of MMP-9 in CRP-induced human THP-1 cells may be associated with activation of NF-κB. Down-regulation of the expression and activity of MMP-9 may be a new treatment alternative for plaque stabilization by inhibiting the NF-κB activation.     

Expression of NF-κB in hRPE Cells Stimulated by PDTC and IL-1β

The constitutive expression of nuclear-factor-κB (NF-κB) in human pigment epithelial (hRPE) cells cultivated in vitro and the possible changes when incubated with PDTC and IL-I were investigated. The synchronized hRPE cells in vitro were divided into two groups. In nonPDTC group, hRPE cells were exposed respectively to IL-1β and NS (for detecting the constitutive expressions of NF-κB in hRPE cells) ; In PDTC group, PDTC-pretreated hRPE cells were exposed respectively to IL-1β?Aand NS. (for detecting the constitutive expression of NF-κB in PDTC-pretreated hRPE cells). The expression of NF-κB in hRPE cells in two groups was detected by immunofluorescence stain and flow cytometry. The results showed that the constitutive expression of NF-κB in hRPE cells in vitro was 8.05 %, and increased to 30.26 % by IL-1β. After PDTC pretreatment, the constitutive expression of NF-κB in hRPE cells was decreased to 3.74%, and 3.66 % by IL-l,respectively. It was concluded that the expressions of NF-κB in hRPE cells could be increased significantly by IL-1βand depressed effectively by PDTC. Also, PDTC could significantly inhibit the activation of NF-κB induced by IL-1β.     

Toll-like receptor 4/nuclear factor-kappa B signaling detected in brain after early subarachnoid hemorrhage

Background Inflammation and immunity play a vital role in the pathogenesis of early brain injury after subarachnoid hemorrhage （SAH）. Nuclear factor-kappa B （NF-κB） regulates many genes essential for inflammation and immunity and is activated by toll-like receptor （TLR）. This study aimed to detect the expression of the toll-like receptor 4/nuclear factor-kappa B （TLR4/NF-κB） signaling in the rat brain after early SAH. Methods The rats were decapitated and their brains were removed at 0, 2, 4, 6, 12, 24 and 48 hours after a single injection of blood into the prechiasmatic cistern, mRNA expression of TLR4 was measured by Taqman real-time RT-PCR, and protein expression by immunohistochemistry and Western blotting. NF-κB activity and concentrations of tumor necrosis factor-alpha （TNF-α）, interleukin-lbeta （IL-1β） and interleukin-6 （IL-6） were measured by enzyme-linked immunosorbent assay （ELISA）. Results TaqMan real-time RT-PCR and Western blotting identified a biphasic change in TLR4 expression in both mRNA and protein： an initial peak （2-6 hours） and a sustained elevation （12-48 hours）. Immunohistochemical staining showed the inducible expression of TLR4-like immunoreactions predominantly in glial cells and vascular endothelium. A similar biphasic change in the activation of NF-κB subunit p65 as well as the production of NF-κB-regulated proinflammatory cytokines （TNF-α, IL-1β and IL-6） were detected by ELISA. Conclusions These data suggest that experimental SAH induces significant up-regulation of TLR4 expression and the NF-κB signaling in early brain injury. Activation of the TLR4/NF-κB signaling may regulate the inflammatory responses after SAH.     

Effect of cefodizime on cytokines expression in mouse neutrophils and its related mechanism

Objective： To explore the regulating effects of cefodizime on cytokines expression of neutrophil response to Klebsiella pneumoniae （Kle. p） treatment. Methods： We detected the types and expression of cytokines secreted by neutrophils by cDNA array and RT-PCR. We also analyzed the changes of signal transduction in this process by detecting the expression of toll like receptor 4 （TLR4） and the inhibitor factor of κBα （I-κBα） expressed by neutrophils. The activity of NF-κB DNA-binding in neutrophils was measured by electrophoretic mobility shift assay （EMSA）. Results： Cefodizime increased the neutrophils production of TNF-α, IL-β3 and the mRNA expression of TLR4 in the early stage of Kle. p stimulation in mice, which seemed corresponding to the enhanced NF-κB DNA-binding activity. Conclusion： Cefodizime regulates the cytokines expression of neutrophils through the LPS-TLR4-NF-κB pathway by affecting the expression of TLR4 mRNA and the DNA binding activities of NF-κB in mice with the challenge of Kle. p.     

Interleukin-13 inhibits cytokines synthesis by blocking nuclear factor-κB and c-Jun N-terminal kinase in human mesangial cells

Objective： Monocytes/macrophages, proinflammatory cytokines and chemokines are important in the pathogenesis of glomerulonephritis. Interleukin （IL） -13 has been shown to exert potent anti-inflammatory properties. This study was designed to investigate the effect of IL-13 on the expression of proinflammatory cytokines, chemokines and profibrogenic cytokines and the involved molecular mechanism in cultured human mesangial cells （HMCs）. Methods： The expressions of proinflammatory cytokines, chemokines and profibrogenic cytokines were determined by ribonuclease protection assay （RPA）. Activity of nuclear factor-kappa B （NF-κB） and activa- tor protein-1 （AP-1） was examined by electrophoretic mobility shift assay （EMSA）. NF-κB subunit p65 nuclear transportation and c-Jun N-terminal kinase （JNK） activity were assayed by immunoblot. Results： Recombinant IL-13 inhibited tumor necrosis factor-α （TNF-u）, IL-1α, IL-1β, monocyte chemoattractant protein-1 （MCP-1）, IL-8, and transforming growth factor-β1 （TGF-β1） mRNA expressions in a dose-dependent manner. Lipopoly- sacchorides （LPS） dramatically increased NF-κB DNA binding activity of HMCs, which was inhibited by IL-13 in a dose-dependent manner. LPS-activated NF-κB contained p50 and p65 dimers, but not c-Rel subunit. IL-13 blocked LPS-induced NF-κB subunit p65. LPS stimulated JNK/AP-1 activation, which was inhibited by IL-13 in a dose-dependent manner. Conclusion： IL-13 inhibits proinflammatory cytokines, chemokines, and profibrogenic cytokines synthesis by blocking NF-κB and JNK/AP-1 activation. These observations point to the importance of IL-13 in the modulation of inflammatory processes in the renal glomerulus.     

Effects of High Concentration Glucose on the Expression of NF-κB, Bax and Cytochrome C and Apoptosis of Islet Cells in Mice

The roles of NF-kappaB （NF-κB） expression, Bax activity and cytochrome C （Cyt C） release, apoptosis of islet cells induced by high concentration glucose were explored in vitro. Pancreatic islet cells, which were isolated from Kunming mice, were cultured with different concentrations of glucose in DMEM, and divided into the following groups： G1, G2, G3, G4, G5, and G6 groups, corresponding to the glucose concentrations of 5.6, 7.8, 11.1, 16.7, 22.5, and 27.6 mmol/L, respectively. After culture for 120 h, insulin secretion was evaluated by radioimmunoassay, and the NF-rd3 expression was detected by immunocytochemistry. Bax activity and Cyt C release were measured by immunofluorescence, and apoptosis was examined by Hoechst33342 assay. The results showed that in GI, G2 and G3 groups, insulin secretion was enhanced with the increase of glucose concentration, and the NF-κB expression was also increased （P〈0.05）, but Bax activity, Cyt C release and apoptosis rate showed no significant difference among them. However, in G4, G5, and G6 groups, apoptosis rate of islet cells, NF-rd3 expression, Bax activity, and Cyt C release were all significantly increased, and insulin secretion was impaired as compared with G1, G2, and G3 groups （P〈0.05）. It was concluded that the exposure of islet cells to high glucose could induce islet cells apoptosis as well as impaired insulin secretion. The NF-κB signaling pathway and mitochondria pathway in islet cells might play some roles in the progressive loss of islet cells in diabetes. The inhibition of the NF-κB expression could be an effective strategy for protecting pancreatic islet cells.     

Study on Effects of Extracts from Salvia Miltiorrhiza and Curcurna Longa in Inhibiting Phosphorylated Extracellular Signal Regulated Kinase Expression in Rat＇s Hepatic Stellate Cells

Objective： To study the effect of salvianolic acid B （SAB） and curcumin, the extracts of Solvie Miltiorrhize and Curcume Longe, on the proliferation and activation of hepatic stellate cell （HSC）, and the extracellular signal regulated kinase （ERK） expression in it. Methods： Rat＇s HSC-T6 were cultured and treated by SAB or curcumin. The inhibitory effect on cell proliferation was determined by 3-（4,5-dimthyl-2- 2thiazoly）-2,5-diphenyl-2H-tetrazolium bromide （MTT） colorimetry, and the expression levels of a smooth actin （a-SMA）, collagen type Ⅰ , and ERK were determined by Western blot. Results： SAB and curcumin inhibited the proliferation and activation of rat＇s HSC-T6 in dose-dependent fashion and significantly reduced the expression level of a-SMA （ P〈0.01 ）. Curcumin significantly reduced the expression of collagen type Ⅰ （P〈0.05）. Both SAB and curcumin showed insignificant effect on the ERK expression level, but they could significantly reduce the level of phosphorylated-ERK expression, showing significant difference as compared with that in the control group （ P〈0.01 and P〈0.05 respectively）. Conclusion： SAB and curcumin could significantly inhibit the proliferation, activation of HSC, and the production of type Ⅰ collagen in HSC, the mechanism may be associated with their inhibition on ERK phosphorylation.     

The role of NF-κB in hepatocellular carcinoma cell

Objective To evaluate the role of nuclear factor-kappaB (NF-κB) and IκBα in hepatocellular cacinoma (HCC) SMMC7721 cells, the consequence of NF-κB inhibition in SMMC7721 cells transfected with mutated IκBα (mIκBα) plasmid and the effect of stable inhibition of NF-κB activity in combination with Doxorubicin.Methods Western blot was used to determine the expression of NF-κB and IκBα in SMMC7721 cells and normal liver cells. Nuclear protein was used to evaluate the binding of the 32P-labeled tandem κB sequence using electrophoretic mobility shift assay and the expression of NF-κB using Western blot between SMMC7721 cells transfected with mIκBα plasmid (SMMC7721-MT) and control cells. Furthermore, cell viability was plotted between SMMC7721-MT and control cells. The binding of κB sequence and cell viability between SMMC7721-MT and control cells at different concentrations of Doxorubicin were also investigated.Results Western blot analysis for nuclear extract showed more P50 (NF-κB1) and P65 (RelA) expression in SMMC7721 cells compared with normal liver cells. The expression of cytosolic IκBα protein in SMMC7721 cells was less than that in normal cells. SMMC7721-MT cells inhibited NF-κB nuclear translocation at 0, 24, 48 and 96 hours. Furthermore, NF-κB cannot be detected in the nuclear protein of SMMC7721-MT cells by Western blot. By calculating cell viability, the proliferation of SMMC7721-MT cells was shown to be suppressed more significantly than that of control cells. NF-κB in untransfected cells was activated by Doxorubicin in a dose-dependent manner, but that in SMMC7721-MT cells was not induced at low concentrations of Doxorubicin. Compared with untransfected cells, the viability of SMMC7721-MT cells was significantly suppressed at the same concentration of Doxorubicin (P<0.01）.Conclusions The present study demonstrates that upregulation of NF-κB and downregulation of inhibitory kappaB (IκBα) in SMMC7721 cells are related with the growth of hepatocellular cacinoma cells. Stable expression of mIκBα in SMMC7721-MT cells can inhibit NF-κB nuclear translocation and suppress cell growth. Furthermore, stable inhibition of NF-κB activity in combination with Doxorubicin can significantly inhibit cell proliferation in SMMC7721-MT cells. Thus, modulation of NF-κB may represent an improvement in the efficacy of HCC therapies and be worthy of further research and investigation.     

Activation of NF-κB in bronchial epithelial cells from children with asthma

Objectives To determine whether nuclear factor-κB (NF-κB) is activated in epithelial cells from children with asthma and to understand the role of NF-κB in airway inflammation in asthma. Methods Bronchial mucosa specimens were obtained from 9 children with asthma and 6 control subjects. NF-κB expression in epithelial cells were detected by immunohistochemical examination, and NF-κB-DNA binding was measured by electrophoretic mobility shift assay (EMSA). Results Nuclear expression of NF-κB in epithelial cells was observed in the 9 asthmatic children. NF-κB-DNA binding was found in 4 asthmatic children (EMSA was performed in 6 asthmatic children). In contrast, both nuclear expression and NF-κB-DNA binding were absent in the 6 control subjects. Conclusion These results indicated that NF-κB is activated in epithelial cells from asthmatic children and the NF-κB activation may be the basis for the increased expression of many inflammatory genes and for airway inflammation in asthma.     

Influence of osteopontin short hairpin RNA on the proliferation and activity of rat vascular smooth muscle cells

To investigate the influence of osteopontin （OPN） short hairpin RNA （shRNA） on the proliferation and activity of rat vascular smooth muscle cells （VSMCs）, the expressing vector of shRNA targeting OPN was constructed and transferred into the rat VSMCs. After amplification and purification, pGenesil-1/OPNshRNA1 （PG1）, pGenesil-1/OPNshRNA2 （PG2） and pGenesil-1/OPNshRNAHK （PGH） were transfected into the cultured rat VSMC by LipofectamineTM 2000. Transfected cells were visualized by using an inverted fluorescent microscope. VSMCs transfected by optimal recombined plasmid was selected by culturing in G418 48 h later. Nude cells and cells transfected by PGH were used as control. The expression levels of OPN mRNA and protein were assayed by RT-PCR and Western blotting. The OPN of VSMCs was suppressed by transfection of optimal recombined plasmid, and the changes in cell proliferation, adhesion and motility were evaluated by MTT, adhesion test and transwell chamber test. Levels of type I and Ⅲ collagen were measured with ELISA kit. Our results showed that VSMCs stably transfected by OPN shRNA accounted for over 50% of total cells. OPN mRNA and protein were reduced by 81% and 67% （P〈0.01） by PG1, 73% and 52% （P〈0.01） by PG2, respectively while no change was found in PGH and non-treated VSMCs. PG1 significantly suppressed the proliferation, adhesion, mobility of VSMCs and reduced the amount of type Ⅰ and Ⅲ collagen. It is concluded that recombinant plasmid can be success-fully transfected into VSMCs by LipofectamineTM 2000 and inhibit the expression of OPN. The proliferation, adhesion and mobility of VSMCs can be inhibited by knocking down OPN expression. Moreover, the transferring capability of cells is attenuated, and the secretion of type Ⅰ and Ⅲ collagen is inhibited aftter knocking-down of OPN expression. The study provides experimental evidence for clinical prevention of restenosis after percutaneous coronary intervention （PCI） by RNA interference （RNAi） technology.     

Inhibiting NF-κB increases cholesterol efflux from THP-1 derived-foam cells treated with AngII via up-regulating the expression of ATP-binding cassette transporter A1

Objective: To study the role of nuclear factor-kappa B(NF-κB) in cholesterol efflux from THP-1 derived-foam cells treated with AngiotensinⅡ(AngⅡ). Methods:Cultured THP-1 derived-foam cells were treated with AngⅡ or preincubated with tosyl-phenylalanine chloromethyl-ketone(TPCK) NF-κB inhibitor. The levels of activated NF-κB in the cells were examined by sandwich ELISA. Cellular cholesterol content was studied by electron microscopy scanning and zymochemistry via fluorospectrophotometer and cholesterol efflux was detected by scintillation counting technique. ABCA1 mRNA and protein were quantified by RT-PCR and Western blotting. Results:Addition of TPCK to the cells before AngⅡ stimulation attenuated the response of NF-κB p65 nuclear translocation induced by AngⅡ and showed no peak in foam cells group and caused a reduction in cholesterol content and an increase in cholesterol efflux by 24.1%(P < 0.05) and 41.1%(P < 0.05) respectively, when compared with AngⅡgroup. In accordance, the ABCA1 mRNA and protein were increased by 30% and 19%(P < 0.05) respectively, when compared with AngⅡ group. Conclusion:AngⅡ can down-regulate ABCA1 in THP-1 derived-foam cells via NF-κB, which leads to less cholesterol efflux and the increase of cholesterol content with the consequence of the promotion of atherosclerosis.     

Inhibiting NF-κB increases cholesterol efflux from THP-1 derived-foam cells treated with AngⅡ via up-regulating the expression of ATP-binding cassette transporter A1

Objective: To study the role of nuclear factor-kappa B(NF-κB) in cholesterol efflux from THP-1 derived-foam cells treated with AngiotensinⅡ(AngⅡ). Methods:Cultured THP-1 derived-foam cells were treated with AngⅡ or preincubated with tosyl-phenylalanine chloromethyl-ketone(TPCK) NF-κB inhibitor. The levels of activated NF-κB in the cells were examined by sandwich ELISA. Cellular cholesterol content was studied by electron microscopy scanning and zymochemistry via fluorospectrophotometer and cholesterol efflux was detected by scintillation counting technique. ABCA1 mRNA and protein were quantified by RT-PCR and Western blotting. Results:Addition of TPCK to the cells before AngⅡ stimulation attenuated the response of NF-κB p65 nuclear translocation induced by AngⅡ and showed no peak in foam cells group and caused a reduction in cholesterol content and an increase in cholesterol efflux by 24.1%(P < 0.05) and 41.1%(P < 0.05) respectively,when compared with AngⅡgroup. In accordance,the ABCA1 mRNA and protein were increased by 30% and 19%(P < 0.05) respectively,when compared with AngⅡ group. Conclusion:AngⅡ can down-regulate ABCA1 in THP-1 derived-foam cells via NF-κB,which leads to less cholesterol efflux and the increase of cholesterol content with the consequence of the promotion of atherosclerosis.     

Effect of surfactant protein A on lipopolysaccharide-induced tumor necrosis factor-α expression in human proximal tubular epithelial cells

Background Surfactant protein A （SP-A） contributes to the regulation of sepsis-induced acute lung injury.In a previous study,we demonstrated the expression and localization of SP-A in the kidneys.The present study evaluated the effect of SP-A on lipopolysaccharide （LPS）-induced tumor necrosis factor-α （TNF-α） expression and its underlying mechanisms in the human renal tubular epithelial （HK-2） cells.Methods Indirect immunofiuorescence assay was used to detect SP-A distribution and expression in HK-2 cells.HK-2 cells were treated with various concentrations of LPS （0,0.1,1,2,5,and 10 mg/L） for 8 hours and with 5 mg/L LPS for different times （0,2,4,8,16,and 24 hours） to determine the effects of LPS on SP-A and TNF-α expression.Then,HK-2 cells were transfected with SP-A siRNA to analyze nuclear factor κB （NF-κB） P65 and TNF-α expression of HK-2 cells after LPS-treatment.Results Indirect immunofluorescence assay revealed that SP-A is localized to the membrane and cytoplasm of HK-2 cells.Interestingly,SP-A1/SP-A2 and TNF-α expression were found to be significantly increased in HK-2 cells upon LPS treatment.Transfection of LPS-treated HK-2 cells with SP-A siRNA resulted in significant increases in the levels of NF-κB P65 protein and TNF-α mRNA and protein compared to those in non-transfected LPS-treated HK-2 cells.Conclusion SP-A plays an important role in protecting cells against sepsis-induced acute kidney injury by inhibiting NF-κB activity to modulate LPS-induced increase in TNF-α expression.