Humans ; Liver Cirrhosis ; metabolism ; RNA, Messenger ; genetics ; Signal Transduction ; Smad Proteins ; metabolism ; Transforming Growth Factor beta1 ; metabolism

OBJECTIVETo investigate the changes in Smad 2, 3, 4 and 7 of the transforming growth factor-beta 1 (TGF-b1)/Smad signaling pathways in carbon tetrachloride (CCL4)-induced hepatic fibrosis rats treated with TGF-b1 small interfering (si)RNA.

METHODSRats were randomly divided among five groups: non-fibrotic (normal); fibrosis-induced (model); fibrotic treated with 0.125 mg/kg TGF-b1 siRNA; fibrotic treated with 0.250 mg/kg TGF-b1 siRNA; and fibrotic treated with negative control TGF-b1 siRNA. The expression of Smad 2, 3, 4 and 7 was detected by real-time polymerase chain reaction (for mRNA), immunohistochemistry and Western blotting (for protein).

RESULTSThe mRNA and protein levels of Smad 2, 3 and 4 were significantly lower in the the fibrotic rats treated with either 0.250 mg/kg or 0.125 mg/kg TGF-b1 siRNA than in the fibrotic model or the negative control TGF-b1 siRNA rats (P less than 0.01). Moreover, the mRNA and protein expression levels of Smad 2, 3 and 4 were significantly lower in the 0.250 mg/kg TGF-b1 siRNA group than in the 0.125 mg/kg group (P less than 0.05). Comparing the 0.250 mg/kg and 0.125 mg/kg TGF-b1 siRNA groups to the model group and the TGF-b1 siRNA negative control group showed significantly increased levels of mRNA and protein expression of Smad 7 (P less than 0.01). In addition, the expression levels of Smad 7 were significantly higher in the 0.250 mg/kg TGF-b1 siRNA group than in the 0.125 mg/kg group (P less than 0.05).

CONCLUSIONsiRNA-mediated silencing of TGF-b1 in rats led to significantly reduced expression of Smad 2, 3 and 4, but significantly increased expression of Smad 7. TGF-b1 regulation of Smad signaling molecules may contribute to hepatic fibrosis in rats and represent a target of future therapeutic intervention.

Animals ; Gene Silencing ; Liver Cirrhosis ; metabolism ; RNA, Small Interfering ; Rats ; Smad Proteins ; metabolism ; Transforming Growth Factor beta1 ; genetics

OBJECTIVETo characterize the role of Smads proteins in alpha 2 (I) collagen (COL1A2) gene expression induced by bone morphogenetic protein-2 (BMP-2) in odontoblast cell line MDPC-23.

METHODSEndogenous Smad protein expression was determined by immunocytochemistry. Smads function and their role in COL1A2 gene expression were investigated in cotransfection experiments using promoter-luciferase reporter gene construct.

RESULTSMDPC-23 cells expressed Smad1, Smad5 and Smad6. BMP-2 promoted the activation of COL1A2 promoter reporter construct. Transient overexpression of Smad1 or Smad5 was enhanced, while overexpression of Smad6 inhibited BMP-2-induced COL1A2 promoter activity. BMP-2 inducibility could be blocked by overexpression of Smad1 or Smad5 dominant negative mutant.

CONCLUSIONSSmad signaling is functioning and appears to be involved in BMP-2-induced COL1A2 collagen transcription in MDPC-23. Smad signaling may play an important role in odontoblast differentiation and dentin extracellular matrix formation mediated by BMP-2.

Animals ; Bone Morphogenetic Protein 2 ; Bone Morphogenetic Proteins ; genetics ; Cell Line ; Collagen ; genetics ; Collagen Type I ; Mice ; Odontoblasts ; cytology ; metabolism ; Smad Proteins ; physiology ; Transforming Growth Factor beta ; genetics

OBJECTIVETo investigate the differential expression of different types of Smads in keloids, normal scars and normal skins and its possible clinicopathological significance.

METHODSRT-PCR and Western blot methods were used to examine the expression of Smads mRNA and proteins level in 10 cases of keloid, in 10 cases of normal scar and in 10 cases of normal skin tissues and fibroblasts. Fibroblasts of keloid, normal scar and normal skin were cultured in vitro. The expression difference were compared and analyzed by t-test, there was statistical difference when P < 0.05.

RESULTSThe mRNA and protein expression of inhibitory Smad7 were significantly down regulated in keloid compared with normal scar (P < 0.05) and normal skin (P < 0.05). However, no significant difference of the mRNA and protein expression of Smad2, 3 and the protein expression of phosphorylation of Smad2, 3 in keloid, normal scar, normal skin tissues and fibroblasts.

CONCLUSIONSThe decreased expression of Smad7 in keloid might play a significant role in the increased TGF-beta1/Smads signal transduction, which can not be terminated by autologous negative feedback cycle.

Adolescent ; Adult ; Female ; Humans ; Keloid ; metabolism ; Male ; Middle Aged ; RNA, Messenger ; genetics ; Signal Transduction ; Smad Proteins ; genetics ; metabolism ; Transforming Growth Factor beta1 ; metabolism ; Young Adult

OBJECTIVETo elucidate the effects of interferon-gamma (IFN-gamma) on the transforming growth factor beta (TGF-beta)/Smad pathway in keloid-derived fibroblasts (KFb), and to investigate the underlying mechanism in the treatment of pathologic scar with IFN-gamma.

METHODSKeloid tissue of 3 patients were obtained, and then KFb were separated and cultured in vitro. KFb from passages 3 to 5 were used for the study. (1) KFb were divided into control group (incubated with serum-free DMEM), TGF-beta(1) group (treated with 10 ng/mL TGF-beta(1)), IFN-gamma group (treated with 100 ng/mL IFN-gamma), and TGF-beta(1)+IFN-gamma group (incubated with 10 ng/mL TGF-beta(1) combined with 100 ng/mL IFN-gamma). The expression level of mRNA and protein of connective tissue growth factor (CTGF), alpha smooth muscle actin (alpha-SMA) protein and expression of alpha-SMA positive KFb were detected by real-time fluorescent quantitation RT-PCR (FQ-RT-PCR), Western blot and immunofluorescence cytochemical staining. (2) Another sample of KFb was obtained and treated with 10 ng/mL IFN-gamma. The expression level of Smad 3 and Smad 7 protein was detected by Western blot before and 1, 2, 4, 6, 8 h post stimulation (PSH). The expression level of Smad 3 and Smad 7 mRNA was assessed by FQ-RT-PCR before stimulation and 30 mins post stimulation and at PSH, 1, 2, 4, 6, 8. (3) Another sample of KFb was obtained and divided into 1, 10 and 100 ng/mL IFN-gamma groups based on the concentration of IFN-gamma, treated for 4 hours; KFb without IFN-gamma treatment was set up as control group. The expression levels of the protein and mRNA of Smad 3 and Smad 7 were measured by FQ-RT-PCR and Western blot.

RESULTS(1) The level of mRNA and protein of CTGF in IFN-gamma group (0.017 +/- 0.009 and 1.198 +/- 0.004) was respectively lower than that in control group (0.024 +/- 0.013 and 1.229 +/- 0.011, P < 0.05). The level of mRNA and protein of CTGF in TGF-beta(1)+IFN-gamma group (0.634 +/- 0.138 and 1.204 +/- 0.010) was respectively lower than that in TGF-beta(1) group (1.331 +/- 0.298 and 1.727 +/- 0.004, P < 0.01). The fluorescence intensity of alpha-SMA positive KFb (0.922 +/- 0.059) and the expression level of alpha-SMA protein (0.3051 +/- 0.0031) in IFN-gamma group decreased significantly than those in control group (1.055 +/- 0.005 and 0.4513 +/- 0.0094, P < 0.01). The fluorescence intensity of alpha-SMA positive KFb (1.129 +/- 0.004) and the expression level of alpha-SMA protein (0.6734 +/- 0.0098) in TGF-beta(1)+IFN-gamma group decreased significantly than those in TGF-beta(1) group (1.270 +/- 0.005 and 1.3842 +/- 0.0024, P < 0.01). (2) The expression level of Smad 3 mRNA and protein at the first time point after IFN-gamma treatment increased temporarily then decreased gradually, and mRNA expression level reached the nadir at PSH 4, it rose gradually later, though it was still lower at PSH 8 than that before treatment (P < 0.01); protein expression level at PSH 8 was significantly lower than that before treatment (P < 0.01). The expression level of Smad 7 mRNA and protein increased gradually to the maximum at PSH 2 and 4 respectively, then decreased but was still higher at PSH 8 than that before treatment (P < 0.05). (3) Compared with those in control group, the expression levels of Smad 3 mRNA and protein in 1, 10 and 100 ng/mL IFN-gamma group were significantly lower, the expression levels of Smad 7 mRNA and protein were significantly higher (P < 0.05 or P < 0.01). The higher concentration of IFN-gamma, the more significant differences were observed.

CONCLUSIONSIFN-gamma can down-regulate the expression of Smad 3 while up-regulate the expression of Smad 7 in a time- and dose-dependent manner, and reduce the expression level of CTGF and alpha-SMA in the basic state or induced by TGF-beta(1), which shows a significant inhibitory effect on the TGF-beta/Smad signal pathway. This may be an important mechanism in the treatment of pathologic scar by IFN-gamma.

Cells, Cultured ; Fibroblasts ; drug effects ; metabolism ; Humans ; Interferon-gamma ; pharmacology ; Keloid ; metabolism ; RNA, Messenger ; genetics ; Signal Transduction ; drug effects ; Smad Proteins ; metabolism ; Transforming Growth Factor beta1 ; metabolism

OBJECTIVETo investigate the effects of YOD1 overexpression on the proliferation and migration of human oral keratinocytes (HOKs), and to clarify whether the mechanisms involve transforming growth factor-β (TGF-β) signaling.

METHODSHOKs were transfected with the plasmid pEGFP-N3-YOD1 containing YOD1. The mRNA levels of YOD1 and TGF-β were determined by qPCR. The protein expressions of YOD1, TGF-β, Smad2/3, Smad4, and phospho-Smad2/3 were determined by western blotting. Cell proliferation and migration were evaluated by Cell Counting Kit-8 assay and wound healing assay, respectively.

RESULTSThe mRNA and protein levels of YOD1 were higher in HOKs transfected with YOD1. YOD1 overexpression significantly enhanced the migration of HOKs. The mRNA and protein levels of TGF-β3 were increased by YOD1 overexpression. HOKs transfected with YOD1 exhibited increased phospho-Smad2/3 levels.

CONCLUSIONYOD1 overexpression enhances cell migration by promoting TGF-β3 signaling which may play an important role in lip and palate formation. YOD1 mutation may contribute to aberrant TGF-β3 signaling associated with decreased cell migration resulting in NSCLP.

Cell Movement ; physiology ; Cell Proliferation ; Cells, Cultured ; Endopeptidases ; genetics ; metabolism ; Humans ; Keratinocytes ; physiology ; Signal Transduction ; physiology ; Smad Proteins ; genetics ; metabolism ; Thiolester Hydrolases ; genetics ; metabolism ; Transforming Growth Factor beta3 ; genetics ; metabolism

AIMTo investigate the molecular mechanism underlying the effect of linoleic acid on plasminogen activator inhibitor type-1 (PAI-1) expression in HepG2 cells.

METHODSHepG2 cells were exposed to different concentrations of linoleic acid and PAI-1 expression was determined by RT-PCR and colorimetric assay. Luciferase reporter gene plasmids containing four sequentially truncated fragments of the PAI-1 promoter region (-804 to +17) were constructed, and plasmids carrying constructs of Smad binding element (SBE)-site directed deletions in PAI-1 promoter were also generated using overlap extention PCR and transiently transfected into HepG2 cells, the transcriptional activity of PAI-1 was demonstrated by the luciferase activity.The effect of linoleic acid on Smad3 and Smad4 protein levels in cultured HepG2 cells was measured by Western blot analysis.

RESULTS(1) Linoleic acid remarkably increased PAI-1 mRNA expression and transcription in varying concentrations. (2) The level of PAI-1 transcription was gradually decreased induced by linoleic acid when transfected the SBE- site directed-deletions plasmids in PAI-1 promoter at -734/-731. (3) Protein levels of both Smad3 and 4 in HepG2 cells were increased by linoleic acid.

CONCLUSIONLinoleic acid regulated the expression of PAI-1 from transcriptional level in HepG2 cells and SBE involved in the regulation, and both Smads protein and Smad signaling pathway acted main role in this procession.

Gene Expression Regulation ; drug effects ; Hep G2 Cells ; Humans ; Linoleic Acid ; pharmacology ; Plasminogen Activator Inhibitor 1 ; genetics ; Promoter Regions, Genetic ; Signal Transduction ; drug effects ; Smad Proteins ; metabolism

OBJECTIVETo explore the effects of blocking two sites of TGF-β/Smads signaling on the formation of scar-related proteins in human skin fibroblasts.

METHODSTwo lentivirus vectors encoding soluble TGF-β receptor II (sTβRII) and mutant Smad 4-Smad 4ΔM4 were respectively transfected into human skin fibroblast cell line human foreskin fibroblast 1 (HFF-1) cells with the optimum multiplicity of infection (MOI) of 50. The protein expressions of sTβRII and Smad 4ΔM4 of the two types of transfected cells were determined by Western blotting so as to compare with those of the untransfected cells. The HFF-1 cells were divided into 6 groups as named below according to the random number table, with 6 dishes in each group, 1×10(4) cells per dish. Co-transfection group, transfected with the two previous lentivirus vectors, mixed with the ratio of 1:1 and MOI of 50, and then stimulated with 5 ng/mL TGF-β1 for 72 h; sTβRII group, transfected with lenti-sTβRII with MOI of 50, with the other treatment as above; Smad 4ΔM4 group, transfected with lenti-Smad 4ΔM4 with MOI of 50, with the other treatment as above; negative virus group, transfected with empty lentivirus vector, with the other treatment as above; positive control group, stimulated with 5 ng/mL TGF-β1 for 72 h; and blank control group, conventionally cultured without any other treatment. After stimulation, Western blotting and real-time fluorescent quantitative RT-PCR were respectively used to determine the protein and mRNA expressions of fibronectin in cells of each group. ELISA and Sircol collagen assay were respectively used to determine the protein expressions of connective tissue growth factor (CTGF) and total collagen in the cell culture supernate of each group. Data were processed with one-way analysis of variance and SNK-(q test).

RESULTS(1) HFF-1 cells transfected with lenti-sTβRII and HFF-1 cells transfected with lenti-Smad 4ΔM4 respectively expressed higher levels of sTβRII protein and Smad 4ΔM4 protein compared with those of untransfected cells, confirming that HFF-1 cells transfected with the two lentivirus vectors can efficiently express the target proteins. (2) There were statistically significant differences in the protein and mRNA expressions of fibronectin in cells of the 6 groups (with F values respectively 53.536 and 24.365, P values below 0.001). The protein and mRNA expressions of fibronectin in cells of positive control group (respectively 1.60 ± 0.18 and 1.99 ± 0.40) were similar with those of negative virus group (respectively 1.60 ± 0.15 and 1.94 ± 0.28, with q values respectively 0.091 and 0.419, P values above 0.05), and they were significantly higher than those of the rest 4 groups (with q values from 5.245 to 18.228, P values below 0.05). The protein and mRNA expressions of fibronectin in cells of co-transfection group (respectively 0.60 ± 0.05 and 0.70 ± 0.11) were significantly lower than those of sTβRII group (respectively 0.89 ± 0.13 and 1.24 ± 0.17) and Smad 4ΔM4 group (respectively 0.91 ± 0.14 and 1.28 ± 0.19, with q values from 3.964 to 4.294, P values below 0.05). (3) There were statistically significant differences in the protein expressions of CTGF and total collagen in the cell culture supernate of the 6 groups (with F values respectively 107.680 and 38.347, P values below 0.001). The protein expressions of CTGF and total collagen in the cell culture supernate of positive control group were similar with those of negative virus group (with q values respectively 1.106 and 0.491, P values above 0.05), and they were significantly higher than those of the rest 4 groups (with q values from 6.414 to 26.420, P values below 0.05). The protein expressions of CTGF and total collagen in the cell culture supernate of co-transfection group were significantly lower than those of sTβRII group and Smad 4ΔM4 group (with q values from 3.424 to 7.143, P values below 0.05).

CONCLUSIONSIn human skin fibroblasts, blockage of two sites of TGF-β/Smad signaling can reduce the expression of scar related proteins which are up-regulated by TGF-β1 to a greater extent than that of blocking one single site.

Cicatrix ; Connective Tissue Growth Factor ; Fibroblasts ; metabolism ; Genetic Vectors ; Humans ; Lentivirus ; genetics ; Protein-Serine-Threonine Kinases ; RNA, Messenger ; genetics ; Receptors, Transforming Growth Factor beta ; Signal Transduction ; drug effects ; Smad Proteins ; genetics ; metabolism ; Smad Proteins, Inhibitory ; genetics ; Transfection ; Transforming Growth Factor beta ; pharmacology ; Transforming Growth Factors

BACKGROUNDAlthough various systemic and local factors such as abnormal carbohydrate or calcium metabolism, aging, and hormonal disturbances have been suggested as causes of ossification of the posterior longitudinal ligament (OPLL), the etiology of OPLL is not fully understood. The purpose of this study was to investigate whether bone morphogenetic protein (BMP)-2 is a candidate gene to modify the susceptibility of OPLL and the mechanism of signal transduction in ossification.

METHODSA total of 420 OPLL patients and 506 age- and sex-matched controls were studied. The complete coding sequence of the human BMP-2 gene was analyzed using polymerase chain reaction (PCR) and direct sequencing. All single nucleotide polymorphisms (SNPs) were detected and genotyped. BMP-2 expression vectors containing positive polymorphisms were constructed and transfected into the C3H10T1/2 cells. The expression of BMP-2 and the Smad signal pathway in positive cell clones were detected by Western blotting. The alkaline phosphatase (ALP) activity was determined using quantitative detection kits.

RESULTSThe frequencies for the 109T > G and 570A > T polymorphisms were different between the case and control groups. The "TG" genotype in 109T > G polymorphism is associated with the occurrence of OPLL, the frequency of the "G" allele is significantly higher in patients with OPLL than in control subjects (P < 0.001). The "AT" genotype in 570A > T polymorphism is associated with the occurrence of OPLL, the frequency of the "T" allele is significantly higher in patients with OPLL than in control subjects (P = 0.005). Western blotting analysis revealed that the expression of P-Smad1/5/8 protein transfected by wild-type or mutant expression vectors were significantly higher than control groups (P < 0.05), but there was no statistical difference in each experimental group (P > 0.05). The expression of Smad4 protein transfected by wild-type or mutant expression vectors was significantly higher than control groups (P < 0.05). The expression of Smad4 protein transfected by pcDNA3.1-BMP2 (109G) and pcDNA3.1-BMP2 (109G, 570T) was significantly higher than the other experimental groups (P < 0.05). The increase in ALP activity has been detected in pcDNA3.1-BMP2 (109G) and pcDNA3.1-BMP2 (109G, 570T) transfected cells up to 4 weeks after stable transfection. Activity of ALP was (30.56 ± 0.46) nmol×min(-1)×mg(-1) protein and (29.62 ± 0.68) nmol×min(-1)×mg(-1) protein, respectively. This was statistically different compared with the other experimental groups (P < 0.05).

CONCLUSIONSBMP-2 is the predisposing gene of OPLL. The "TG" genotype in the 109T > G and the "AT" genotype in the 570A > T polymorphisms are associated with the occurrence of OPLL. The 109T > G polymorphism in exon-2 of the BMP-2 gene is positively associated with the level of Smad4 protein expression and the activity of ALP. The Smad mediated signaling pathway plays an important role during the pathological process of OPLL induced by SNPs of BMP-2 gene.

Adult ; Aged ; Bone Morphogenetic Protein 2 ; genetics ; Cells, Cultured ; Female ; Humans ; In Situ Hybridization ; Longitudinal Ligaments ; metabolism ; Male ; Middle Aged ; Polymorphism, Single Nucleotide ; genetics ; Signal Transduction ; genetics ; physiology ; Smad Proteins ; metabolism ; Spine ; metabolism

OBJECTIVETo investigate the cytotoxic effect of epigallocatechin gallate (EGCG) on human hepatocellular carcinoma cell line HepG2 cells and corresponding changes of TGF-beta1-Smad pathway.

METHODSThe cytotoxic effect of EGCG on HepG2 cells was determined by MTT assay. Cell cycle and apoptosis rate were detected by flow cytometry. RT-PCR and luciferase assay were used to verify whether TGF-beta1-Smad signaling pathway is intact in HepG2. The mRNA expression of Smad 2, Smad3, Smad4 and Smad7 was detected by real-time PCR.

RESULTSEGCG induced apoptosis in the HepG2 cells in a time- and concentration-dependent manner. The proportion of G(1) phase cells was increased gradually as the concentration increased. However, the percentage of cells in S phase was decreased gradually. Annexin V/PI assay demonstrated that early apoptosis increased as the concentration increased, and late apoptosis also increased, when treated with high-concentration EGCG. The intact TGF-beta1-Smad pathway was verified by luciferase assay and RT-PCR. There was no significant effect of EGCG on mRNA level of Smad 2, Smad 3, and Smad 4 in HepG2 cells, but downregulated mRNA level of Smad 7.

CONCLUSIONEGCG can reduce apoptosis in human hepatocellular carcinoma cell line HepG2 cells. The activation of TGF-beta1-Smad signaling pathway may be involved in its cytotoxicity mechanisms.

Anticarcinogenic Agents ; pharmacology ; Apoptosis ; drug effects ; Catechin ; analogs & derivatives ; pharmacology ; Cell Cycle ; drug effects ; Hep G2 Cells ; Humans ; RNA, Messenger ; metabolism ; Signal Transduction ; Smad Proteins ; genetics ; metabolism ; Smad7 Protein ; genetics ; metabolism ; Transforming Growth Factor beta1 ; metabolism