Colonic expression of Runx3 protein and TGF-β(1) and their correlation in patients with irritable bowel syndrome

ObjectiveTo investigate the role of Runx3 protein and TGF-β₁ in the pathogenesis of irritable bowel syndrome (IBS), as well as the correlation of these two proteins.MethodsColonic tissue was collected from patients with IBS and normal persons. The colonic expression of Runx3 protein and TGF-β₁ was detected with immunohistochemistry method. Semi-quantitative analysis was used to evaluate the staining degree of these two proteins.ResultsCompared with their counterparts, patients with IBS did not show any changes in the colonic expression of Runx3 protein and TGF-β₁ (P>0.05). Interestingly, there was a significant correlation between Runx3 protein and TGF-β₁ in patients with IBS(P<0.05).ConclusionsThe role of Runx3 protein and TGF-β₁ in the pathogenesis of IBS remains to be further studied.     

Study on the expression of Runx3 and TGF-β₁ protein in the colonic tissue from rats with irritable bowel syndrome

ObjectiveTo investigate the expression of Runx3 and TGF-β₁ protein in the colon from rats with irritable bowel syndrome (IBS).MethodsRat model for IBS was established by intracolonic instillation with acetic acid and restraint stress methods, which was confirmed by determinating the visceral sensitivity of the animals, including abdominal withdrawal reflex (AWR) score and the electronic behavior of the abdomen wall. The rats were randomly assigned into three groups: IBS₁ group (restraint stress, n = 25); IBS₂ group (both instillation with acetic acid and restraint stress, n = 25) and Control group (n=16). The colonic tissue samples were collected for histological study and the expression of Runx3 and TGF-β₁ proteins were detected by immunohistochemistry. Meanwhile, the relationship of these two proteins was calculated.ResultsVisceral hypersensitivity (AWR and abdominal electrical activity) was significantly enhanced in IBS₁ and IBS₂ groups than other groups. The colon tissue in all groups did not show any signs of inflammation. Furthermore, the expression of Runx3 and TGF-β₁ protein in the colon from all groups show no significant difference (P>0.05), with no remarkable relevancy between each other (P>0.05).ConclusionsThe rat model for IBS was successfully established. We did not find any significant changes in the expression of Runx3 and TGF-β₁ protein in the colon tissue from IBS rats, suggesting that the quantitative changes may be not the way by which Runx3 and TGF-β₁ protein play their roles in IBS. The accurate roles of Runx3 and TGF-β₁ proteins in the pathogenesis of IBS remains to be further studied.     

TGF-β1 signal pathway in the regulation of inflammation in patients with atrial fibrillation

ObjectiveTo observe the expression changes of inflammatory markers TGF-β1, Smad3 and IL-6 in patients with atrial fibrillation (AF), and to explore the significance of TGF-β1 signaling pathway in the structural remodeling of AF.MethodsThe expression of TGF-β1, Smad3 and IL-6 in 50 cases with AF and 30 normal cases were detected by RT-PCR and ELISA.ResultsThe TGF-β1, Smad3 and IL-6 mRNA and protein expression levels in patients with AF were significantly higher than that in the control group (P<0.05), but there was no significantly different between the paroxysmal AF group and the persistent AF group (P>0.05). The TGF-β1mRNA expression in the ? 50 years subgroup was significantly higher than that in the <50 years subgroups, and it was higher in the NYHA III subgroup than in the I/II grade subgroup. It was also higher in the left ventricular ejection fraction (LVEF) <50% subgroup than in LVEF ? 50% group, and it was significantly higher in the AF time ? 36 months subgroup than that in <36 months subgroup (P<0.05). The Smad3 and IL-6 expressions in the in the LVEF <50% subgroup were both high that than that in LVEF ? 50% group, and higher in the AF time ? 36 months subgroup than that in <36 months subgroup (P<0.05). There were a positive correlation between TGF-β1, Smad3 and IL-6 (r=0.687, r=0.547). There were also a positive correlation between Smad3 and IL-6 mRNA (r=0.823).ConclusionsAF is associated with inflammation, and the inflammation is also involved in the fibrillation and sustain of AF. The TGF-β1 signal pathway may be involved in the process of atrial structural remodeling in patients with AF, and iss related with the occurrence and maintenance of AF.     

TGF-β1 Secreted by Hepatocellular Carcinoma Induces the Expression of the Foxp3 Gene and Suppresses Antitumor Immunity in the Tumor Microenvironment

Aim

The purpose of this study was to explore the mechanisms of TGF-β1 mediated immunosuppression in tumor stroma.

Methods

The expression of TGF-β1 was investigated in Huh7, Hep 3B, SGC-7901, Eca-109 and Hepa1-6 cell lines using immunofluorescence. Knocked-down TGF-β1 of the Hepa1-6 cell line was established through lentivirus-based RNA interference. The interference efficiency of the TGF-β1 gene was tested by real-time PCR and ELISA; the expression of Foxp3, IFN-γ and CD83 in CD4⁺, CD8⁺ or dendritic cells was examined via flow cytometry; and the tumorigenic ability of the cancer cells was investigated in the animal experiments.

Results

The diverse digestive cancer cells were found to secrete TGF-β1, mRNA of which was knocked down by 78 % thanks to lentivirus-based interference in Hepa1-6 cells. Flow cytometry showed that CD4⁺CD25⁺Foxp3⁺ regulatory T cells significantly increased in hepatocellular carcinoma patients when compared with those in the healthy controls. The supernatant from Hepa1-6 cells and recombinant TGF-β1 significantly induced the expression of Foxp3 gene in vitro, while that from sh TGF-β1 Hepa1-6 cells restored it. Hepa1-6 cells inhibited IFN-γ and CD83 expression in CD8⁺ or dendritic cells by secreting TGF-β1. The animal experiments indicated that the knockdown TGF-β1 gene impaired the tumorigenic ability of Hepa1-6 cells.

Conclusion

TGF-β1, expressed in cancer cells, might be a potential therapeutic target for cancer treatment.     

The regulatory impact of immune inhibitors on T cells of SD rats

Objective:To observe the regulatory impact of immune inhibitors on T cells in rats.Method:Forty SD rats were selected and randomly divided into experimental group and control group.Rapamycin(SRL)0.4 mg/d to fill the stomach of the former one,saline lavage was used with the latter one for two weeks.Using flow cytometry to detect the two groups of rats with spleen and thymus level of CD4+CD25+T cells;and the spleen cells FoxP3 mRNA expression;Using ELISA method to detect TGF-β,IL-10 levels.Results:The peripheral blood,spleen and thymus of CD4+CD25+T cells accounted for the proportion of mononuclear cells were significantly higher than that of control group(P0.05);FoxP3 mRNA expression quantity also significantly higher than the control group(P0.05);Experimental TGF-βin rats,IL-10 levels are significantly higher than control group(P0.05).Conclusions:Immune inhibitors can regulatory CD4+CD25+foxp3+T cells in rats,a single nuclear cell proportion increase,shows that it can induce rat CD4+CD25+foxp3+regulatory T cells proliferation.     

Effect of bone marrow mesenchymal stem cells on the Smad expression of hepatic fibrosis rats

Objective:To investigate the impact of bone marrow mesenchymal stem cells on Smad expression of hepatic fibrosis rats.Methods:A total of 48 adult female SD rats were randomly divided into three groups,normal control group(n=10),observation group(n=19)with liver fibrosis model rats injected with BMSCs cells:model group(n=19),with liver fibrosis model rats injected with physiological saline.Serum index,TGF-β1 and Smad expression were detected.Results:TypeⅢprocollagen,Ⅳcollagen,hyaluronic acid,laminin levels of observation group were significantly lower than those of model group(P0.05).The content and expression of TGF-β1in serum and liver tissue of observation group were significantly lower than those of model group(P0.05).Compared with normal control group,the Smad3,Smad4 mRNA and protein expression of model group were significantly increased,the Smad7 mRNA and protein expression were significantly reduced(P0.05).Compared with model group.Smad3,Smad4 mRNA and protein expression of observation group were significantly reduced,and Smad7 mRNA expression were significantly increased(P0.05).Conclusions:BMSCs can regulate Smad expression to some extent,and reduce the degree of liver fibrosis.     

Vascular endothelial growth factor (VEGF164) ameliorates intestinal epithelial injury in vitro in IEC-18 and Caco-2 monolayers via induction of TGF-β release from epithelial cells

Objective. VEGF is a glycoprotein with various (e.g. angiogenic) activities. So far, research has focused on its angiogenic properties. VEGF receptors are localized on epithelial cells of patients with inflammatory bowel disease (IBD) and also on Caco-2 and IEC-18 cells. Our aim was to evaluate the role of VEGF on intestinal epithelial cell (IEC) migration and proliferation by utilizing an established in vitro model. Methods. IEC-18 and Caco-2 monolayers were wounded with a razor blade as described previously. Cells were incubated in medium w/o rat VEGF₁₆₄. After 24?h, migration was assessed by counting cells across the wound edge. Migration was blocked with neutralizing TGF-β₁ antibodies. IEC proliferation was assessed using the MTT (3-[4, 5-Dimethylthiazol-2-yl]-2, 5-diphenyl-tetrazolium bromide) test. Semi-quantitative changes of the TGF-β₁ mRNA expression were evaluated before and after stimulation of the cells with VEGF₁₆₄ by RT-PCR. Statistical analysis was performed with ANOVA and the Wilcoxon test. Results. VEGF₁₆₄ significantly induced epithelial cell migration in Caco-2 and IEC-18 cells compared to control. TGF-β₁ antibodies completely abolished this VEGF-induced cell migration. TGF-β₁ mRNA significantly increased in IEC-18 and Caco-2 cells after stimulation with VEGF. VEGF significantly inhibited epithelial cell proliferation in IEC-18 and in Caco-2 cells, indicating that the observed effects on cell migration were not due to any proliferate effects. Conclusion. VEGF effects on epithelial cell migration play an important part in epithelial cell restitution by maintaining mucosal homeostasis after mucosal injury. This effect is mediated by TGF-β₁. Our results obtain another possible role for increased VEGF levels in the intestinal mucosa of patients with IBD as reported recently by others.     

Effect of matrine on transforming growth factor β1 and hepatocyte growth factor in rat liver fibrosis model

Objective:To observe the preventive and control effect of matrine on transforming growth factor(TCF- β1) and hepatocyte.growth factor(HCF) of liver fibrosis tissue in rals.Methods:A total of48 SD rats were randomly divided into A,B,C,D groups with 12 in each,group A as the normal control group and groups B.C,D as liver fibrosis models using composite modulus method with carbon tetrachloride(CCL_4).Group B was the model group,group C adopted γ— interferon lavage therapy in the second day of modeling,and group D adopted matrine lavage treatment,at 4 and8 weeks after treatment.Six rats were executed for detection of TGF- β1 and HGF,liver tissue histology and comparison fibrosis degree changes of rat liver tissue between groups.Results:Croups B,C,D showed a more significantly increased TCF- β1 at each time point compared with group A(P0.05);Group B showed a more significantly increased TGF- β1 than groups C and D at weeks 4 and 8(P0.05);group D showed a lowest level of TGF-β1,followed by groups C and B.HGF of group B decreased more significantly than A group at weeks 4 and 8(P0.05);HGF of groups C and D was significantly elevated at 4 and 8 weeks than groups A and B(P0.05),in which the group D showed the highest level of HGF.According to tissue histologic observation,rat liver tissue structure of group A was clear and normal,tissue structure of group B was destroyed with obvious fibrous tissue hyperplasia and fatty change of hepatic cells;groups C and D showed a slighter liver tissue damage,cell necrosis and connective tissue hyperplasia in collect abbacy than group B with a trend of obvious improvement.Conclusions:Matrine can reduce TGF- β1expression and enhance the activity of HGF,so as to realize the inhibition effect on liver fibrosis in rats.     

芍药苷对小鼠巨噬细胞产生TGF-β1的影响

目的 探讨芍药苷（paeoniflorin,PAE）对血吸虫可溶性虫卵抗原（SEA）刺激小鼠腹腔巨噬细胞（PMs）产生转化生长因子β1（TGF-β1）的影响。 方法 研磨法制备SEA,分别加入含有小鼠PMs的培养板、培养瓶及培养皿中,培养24 h,ELISA法测定TGF-β1含量,RT-PCR检测PMs内TGF-β1基因的表达,Western blotting检测PMs内TGF-β1蛋白的表达;在含PMs的培养瓶和培养皿中分别加入10 mg/L SEA 5 ml,培养12 h,再分别加入不同浓度的PAE（0、7.5、15、30、60及120 mg/L）,继续培养12 h和24 h。RT-PCR与蛋白质印迹（Western blotting）分别检测PAE对SEA刺激的PMs内TGF-β1基因与蛋白的表达。 结果 10 mg/L的SEA可明显刺激PMs产生TGF-β1（235.86±3.43 ng/L）,PAE呈浓度依赖性地抑制TGF-β1 mRNA的表达（r=-0.827,P＜0.01）和TGF-β1蛋白的表达（r=-0.952,P＜0.01）。结论 PAE能抑制SEA刺激的PMs产生TGF-β1。     

Irritable Bowel Syndrome on Inflammatory Bowel Disease in Deep Remission: No Relation with Remission Deepening and Inflammation

Background: The aim of the study was to establish the frequency of irritable bowel syndrome (IBS) in patients with inflammatory bowel disease (IBD) in clinical, endoscopic, and histologic remission and in relation to both the depth of remission and inflammation markers. Methods: Patients with ulcerative colitis (UC) and with Crohn’s disease (CD) in clinical remission for at least 6 months were enrolled in the study. All of the patients underwent colonoscopy, and biopsy specimens were taken to evaluate endoscopic and histopathologic remission. Patients were evaluated according to Rome III criteria for IBS. Fecal calprotectin level and blood samples for C-reactive protein (CRP), sedimentation rate, and fibrinogen levels were studied.Results: IBS frequency was 20.9% in UC cases and 28.9% in CD cases in clinical remission. Rates with and without endoscopic remission in UC (20.5% vs. 22.2%, P = .727) and CD (25% vs. 33.3%, P = .837, respectively) were not different. Similarly, rates with and without histopathologic remission in UC (15.7% vs. 26.6%, P = .723), and CD (21.4% vs. 33.3%, P = .999) were not statistically different. Also, it was not related to inflammation markers.Conclusion: IBS frequency among IBD patients with remission was in a substantial rate; these rates kept up with the process of deep remission and even complete mucosal healing and were irrelevant to inflammation.     

Transforming growth factor-β1 gene expression in hepatocellular carcinoma: A preliminary report

Background and study aimsThe transforming growth factor (TGF)-β signalling pathway plays a dual role in hepatocarcinogenesis. It has been recognised for its role as a tumour suppressor as well as a tumour promoter depending on the cellular context.The aim of this study was to investigate the clinical significance of serum TGF-β1 level and TGF-β1 messenger RNA (mRNA) in the peripheral blood of liver cirrhosis and hepatocellular carcinoma (HCC) patients as noninvasive biomarkers in diagnosing HCC.Patients and methodsTwenty patients were allocated to each of the liver cirrhosis and HCC groups, in addition to 20 healthy volunteers. TGF-β1 gene expression in peripheral blood was quantitated using real-time polymerase chain reaction (PCR), while serum TGF-β1 was analysed using enzyme-linked immunosorbent assay (ELISA).ResultsTGF-β1 gene expression was significantly lower in HCC patients (median 0.401 (0.241–0.699) fold change) than in liver cirrhosis patients (median 0.595 (0.464–0.816)) (p = 0.042) and normal controls (median 1.00 (0.706–1.426) fold change) (p = 0.001). TGF-β1 gene expression showed significant positive correlation with serum TGF-β1 (r = 0.272, p = 0.036) and significant negative correlation with alpha-fetoprotein (AFP) (r = −0.528, p = 0.001). Receiver operating characteristic (ROC) analysis was conducted for TGF-β1 gene expression in comparison with AFP. The area under the curve for TGF-β1 gene expression was 0.688 (95% CI = 0.517–0.858) (p = 0.042) and AFP was 0.869 (95% CI = 0.761–0.976) (p = 0.001). The sensitivity and specificity of TGF-β1 gene expression were 65% and 75%, respectively, at a cutoff value of 0.462 fold change.ConclusionTGF-β1 gene expression in the peripheral blood may be used as a molecular marker for the diagnosis of HCC. Additional studies on a large-scale population are necessary to gain greater insight into the impact of TGF-β1 gene expression in the pathogenesis of HCC.     

Enterocyte dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin expression in inflammatory bowel disease

AIM: To investigate dendritic cell-specific intercellular adhesion molecule-3-grabbing non-integrin(DC-SIGN) expression in intestinal epithelial cells(IECs) in inflammatory bowel disease(IBD).METHODS: The expression of DC-SIGN in IECs was examined by immunohistochemistry of intestinal mucosal biopsies from 32 patients with IBD and 10 controls.Disease activity indices and histopathology scores were used to assess the tissue lesions and pathologic damage.Animal studies utilized BALB/c mice with dextran sodium sulfate(DSS)-induced colitis treated with anti-P-selectin lectin-EGF domain monoclonal antibody(PsL-EGFmA b).Controls,untreated and treated mice were sacrificed after 7 d,followed by isolation of colon tissue and IECs.Colonic expression of DC-SIGN,CD80,CD86 and MHC Ⅱ was examined by immunohistochemistry or flow cytometry.The capacity of mouse enterocytes or dendritic cells to activate T cells was determined by coculture with naive CD4+ T cells.Culture supernatant and intracellular levels of interleukin(IL)-4 and interferon(IFN)-γ were measured by enzyme-linked immunosorbent assay and flow cytometry,respectively.The ability of IECs to promote T cell proliferation was detected by flow cytometry staining with carboxyfluorescein diacetate succinimidyl ester.RESULTS: Compared with controls,DC-SIGN expression was significantly increased in IECs from patients with Crohn's disease(P 0.01) or ulcerative colitis(P 0.05).DC-SIGN expression was strongly correlated with disease severity in IBD(r = 0.48; P 0.05).Similarly,in the DSS-induced colitis mouse model,IECs showed upregulated expression of DC-SIGN,CD80,CD86 and MHC,and DC-SIGN expression was positively correlated with disease activity(r = 0.62: P 0.01).IECs from mouse colitis stimulated naive T cells to generate IL-4(P 0.05).Otherwise,dendritic cells promoted a T-helper-1-skewing phenotype by stimulating IFN-γ secretion.However,DC-SIGN expression and T cell differentiation were suppressed following treatment of mice with DSS-induced colitis with Ps L-EGFm Ab.The proliferation cycles of CD4+ T cells from mice with DSS-induced colitis appeared as five cycles,which was more than in the control and treated groups.These results suggest that IECs can promote T cell proliferation.CONCLUSION: IECs regulate tissue-associated immune compartments under the control of DC-SIGN in IBD.     

N-acetyl-l-cysteine inhibits TGF-β1-induced profibrotic responses in fibroblasts

BackgroundExcessive production of TGF-β₁ plays a key role in the tissue remodeling or fibrotic process observed in bronchial asthma, chronic pulmonary disease (COPD), and idiopathic pulmonary fibrosis (IPF). TGF-β₁ has been reported to decrease the intracellular glutathione level and stimulate the production of reactive oxygen species.ObjectivesThe aim of this study was to evaluate whether the antioxidant N-acetyl-l-cysteine (NAC) can affect TGF-β₁-mediated tissue remodeling in fibroblasts or modulate the production of fibronectin and vascular endothelial growth factor (VEGF) which are believed to be important mediators of tissue repair and remodeling.MethodsTo accomplish this, human fetal lung fibroblasts (HFL-1) were used to assess the effect of NAC on the TGF-β₁-mediated contraction of floating gels and the TGF-β₁-induced mediator production. In addition, the effect of NAC on the TGF-β₁-induced differentiation to myofibroblasts was evaluated by assessing α-smooth muscle actin (α-SMA) expression.ResultsNAC significantly abolished the TGF-β₁-augmented gel contraction (at 3 mM, gel size 63.4 ± 2.6% vs. 39.1 ± 4.1%; p < 0.01) compared with control in a concentration-dependent manner. NAC also significantly inhibited the TGF-β₁-augmented fibronectin (p < 0.01) and VEGF (p < 0.01) production in the media of both the three-dimensional gel and monolayer culture. Furthermore, NAC reversed the TGF-β₁-stimulated α-SMA expression (p < 0.01).ConclusionThese results suggest that NAC can affect the TGF-β₁-induced tissue remodeling or fibrotic process in vitro.     

Interferon-γ mediates the immunosuppression of bone marrow mesenchymal stem cells on T-lymphocytes in vitro

Objectives: In the present study, we first confirmed the suppressive function of MSCs in allogeneic T cell proliferation and then examined the underlying mechanisms for MSCs’ immunomodulation and the role of the pro-in?ammatory cytokine interferon (IFN)-γ.

Methods: Human MSCs were cultured in the presence or absence of IFN-γ. The expression level of prostaglandin E₂ (PGE₂), hepatocyte growth factor (HGF), transforming growth factor (TGF)-β₁ and indoleamine 2,3-dioxygenase (IDO) by MSCs were measured. T lymphocytes were isolated from peripheral blood of healthy donors and then induced to proliferate under the stimulation of anti-human CD3 mAb and anti-human CD28 mAb. In the presence of MSCs, T cell proliferation was examined by BrdU incorporation. In addition, PGE₂, HGF, TGF-β₁, Kynurenine, recombinant human IFN-γ and anti-IFN-γ mAb were added and cell proliferation was examined.

Results: Compared to the controls (MSCs alone), MSCs cocultured with IFN-γ expressed significantly higher concentrations of PGE₂, HGF and TGF-β₁. The mRNA level of IDO was remarkably increased. Human bone marrow-derived MSCs alone notably suppressed T lymphocytes proliferation in vitro. Addition of exogenous IFN-γ did not ablate the immunosuppressive effects of MSCs. Addition of anti-IFN-γ mAb partially restored suppression of T cell proliferation by MSCs.

Conclusions: Human MSCs constitutively expressed immunosuppressive levels of PGE₂, HGF and TGF-β₁. The proinflammatory cytokine IFN-γ exhibited synergistic effects with MSCs on immunosuppression, possibly by up-regulating PGE₂, HGF and TGF-β₁ in MSCs and inducting MSCs expression of IDO, involved in tryptophan catabolism.     

Histone deacetylase inhibitor suberoylanilide hydroxamic acid alleviates liver fibrosis by suppressing the transforming growth factor-β1 signal pathway

Background: Histone deacetylases(HDACs) inhibitors are new anti-fibrotic drugs that inhibit the activity of hepatic stellate cells. The present study focused on the anti-fibrotic function of HDAC inhibitor suberoylanilide hydroxamic acid(SAHA) by suppressing transforming growth factor-β1(TGF-β1) signaling. Methods: Male Sprague-Dawley rats were used to induce liver fibrosis with carbon tetrachloride(CCl 4) and LX2 cell(human hepatic stellate cell line) was stimulated by TGF-β1. Both animals and cells were treated with SAHA. The Smad7 and connective tissue growth factor(CTGF) mRNA levels were detected by real-time polymerase chain reaction(PCR). Western blotting was used to examine the protein levels of CTGF, Histone H3(H3), Smad7, Smad2/3, Acetyl-Histone H3(AH3), HDAC2, α-smooth muscle actin( α-SMA), HDAC6, p-Smad2/3 and HDAC8. In addition, the TGF-β1 and liver enzyme levels from rat serum were detected. Histopathological changes were examined by hematoxylin and eosin(HE), Sirius red and Masson trichrome staining. The α-SMA expression was detected by immumohistochemical staining. Results: Compared with control group, the TGF-β1 and liver enzyme levels from rat serum, together with the mRNA levels of CTGF and protein levels of CTGF, HDAC2, α-SMA, HDAC6, p-Smad2/3 and HDAC8 were elevated in fibrotic rats( P 0.01). But the Smad7 mRNA and AH3 protein levels were notably suppressed in the fibrotic rats( P 0.01). Pathological examination showed the typical changes of liver fibrosis in the fibrotic rats. After the treatment with SAHA, the levels of liver enzymes, TGF-β1, CTGF, HDAC2, α-SMA, HDAC6, p-Smad2/3 and HDAC8 were reduced( P 0.01) and Smad7 and AH3 protein contents were elevated in liver fibrotic rats( P 0.01). Moreover, immumohistochemistry showed that SAHA significantly suppressed the α-SMA protein content in fibrotic liver( P 0.01). Conclusion: The HDAC inhibitor SAHA alleviated liver fibrosis by suppressing the TGF-β1 signaling.     

The Role of CTGF in Inflammatory Responses Induced by Silica Particles in Human Bronchial Epithelial Cells

Background

Prolonged exposure to crystalline silica leads to persistent pulmonary inflammation and progressive fibrosis. Connective tissue growth factor (CTGF) has emerged as a potent proinflammatory and profibrotic regulator to participate in a variety of chronic inflammatory diseases. However, the role of CTGF in silica-induced pulmonary inflammation remains poorly understood.

Methods

To explore the effect of CTGF on inflammatory responses caused by silica particles, human bronchial epithelial cells (16HBE) were transfected with CTGF siRNA and exposed to silica particles at concentrations of 0, 12.5, 25, 50, 100 μg/ml for 48 h. Intracellular CTGF mRNA and protein expressions were determined by RT-PCR and Western blotting, respectively. The levels of inflammatory cytokines including IL-8, TNF-α, IL-6, IL-1β, IL-17A and TGF-β₁ were measured by ELISA kits.

Results

Silica particles induce significantly elevated intracellular CTGF mRNA expression in 16HBE cells in a dose-dependent manner when compared with blank control group (P < 0.05). The secretions of IL-8, TNF-α, IL-6 and IL-17A were also significantly increased by silica particles (P < 0.05). After exposure to 25 or 50 μg/ml silica particles, the expression of intracellular CTGF mRNA was significantly inhibited in 16HBE cells when transfected with CTGF siRNA (P < 0.05). The secreted levels of IL-8, TNF-α, IL-6 and IL-17A induced by silica particles were also significantly lower from CTGF siRNA-transfected cells than that from normal 16HBE cells (P < 0.05).

Conclusion

Inhibition of CTGF gene attenuates silica-induced inflammatory responses in bronchial epithelial cells, suggesting that CTGF could be a pivotal regulator in the development of silica-induced inflammation.