Objective To investigate the effects of asiaticoside onthe proliferation and the Smad signal pathway of the hypertrophic scar fibroblasts.Methods The hypertrophic scar fibroblasts were cultured with tissue culture method. The expressions of Smad2 and Smad7 mRNA after asiaticoside treatment were determined by reverse transcriptionpolymerase chain reaction 48 hours later. Thecell cycle, the cell proliferation, the cell apoptosis and the expression of phosphorylated Smad2 and Smad7 with(experimental group) or without(control group) asiaticoside were detected with flow cytometry, immunocytochemistry and Western blot. Results Asiaticoside inhibited the hypertrophic scar fibroblasts from phase S to phase M. The Smad7 content and the expression of Smad7 mRNA were (1.33±1.26)% and (50.80±22.40)% in experimental group, and (9.15±3.36)% and (32.18±17.84)% in control group; there were significant differences between two groups (P＜0.05). While the content and the mRNA expression of Smad2 had no significant difference between two groups. Conclusion Asiaticoside inhibits the scar formation through Smad signal pathway.
Objective To investigate whether miRNA (miR)-34a mediates oxaliplatin (OXA) resistance of colon cancer cells by inhibiting macroautophagy via the transforming growth factor (TGF)-β/Smad4 pathway. Methods miR-34a expression levels were detected in colon cancer tissues and colon cancer cell lines by quantitative real-time polymerase chain reaction (qRT-PCR). Computational search, functional luciferase assay, and Western blotting method were used to demonstrate the downstream target of miR-34a in colon cancer cells. Cell viability was measured with cell counting kit-8. Apoptosis and macroautophagy of colon cancer cells were analyzed by flow cytometry and transmission electron microscopy, and expressions of Beclin1 and LC3Ⅱ protein were detected by Western blotting method. Results Expression of miR-34a was significantly reduced while expressions of TGF-β and Smad4 mRNA were increased in colon cancer patients treated with OXA-based chemotherapy. OXA treatment also resulted in decreased miR-34a expression levels and increased TGF-β and Smad4 expression levels in both parental cells and the OXA-resistant colon cancer cells. Activation of macroautophagy contributed to OXA resistance in colon cancer cells. Expression levels of Smad4 and miR-34a in colon cancer patients had a significant inverse correlation and overexpressing miR-34a inhibited macroautophagy activation by directly targeting Smad4 through the TGF-β/Smad4 pathway. OXA-induced downregulation of miR-34a and increased drug resistance by activating macroautophagy in colon cancer cells. Conclusion miR-34a mediates OXA resistance of colon cancer by inhibiting autophagy via the TGF-β/Smad4 pathway.
Objective To construct and verify a genetically engineered mouse model which is similar to clinical sporadic colorectal cancer and simultaneously expresses KrasLSL-G12D/- and Smad4loxp/loxp genes. Methods The Krastm4Tyj/J mouse and Smad4tm2.1Cxd/J mouse were transformed into the genetic background, and the genotypes of the offspring mice were identified by the PCR to obtain the mice expressed simultaneously KrasLSL-G12D/- and Smad4loxp/loxp genes. The LentivirusCre-IRES-Luciferase was injected into the submucosa of the model mice and the tumorigenicity was observed under the IVIS system. The tumor tissues of the model mice were sampled and the HE staining was used to verify the tumorigenicity of the model mice. Results The genetically engineered mouse model which could simultaneously express KrasLSL-G12D/- and Smad4loxp/loxp genes was obtained by the breeding and selection. The mouse intestinal epithelial cell carcinogenesis was successfully induced by the viral vector containing Cre recombinase. Conclusion Mouse model expressed simultaneously KrasLSL-G12D/- and Smad4loxp/loxp genes is capable of sporadic tumorigenicity by Cre recombinase and could simulate pathological process of human sporadic colorectal cancer.
Objective To investigate the mechanism of bone morphogenetic protein-4 (BMP4) in promoting the recovery of small intestinal mucosal barrier function during the recovery period of small intestine ischemia-reperfusion (I/R) injury. Methods Twenty-eight C57BL/6J male mice aged 6–8 weeks were randomly selected and assigned to small intestine I/R group (n=24) and sham operation (SO) group (n=4) by random number table method. Small intestine I/R injury models of 24 mice were established, then 4 mice were randomly selected at 6, 12, 24 and 48 h after I/R established modeling and killed to observe the morphological changes of small intestinal mucosa and detect the expression of BMP4 mRNA in the jejunal epithelial cells, the other 8 mice were allocated for the experimental observation at the recovery period of small intestine I/R injury (24 h after I/R was selected as the observation time point of recovery period of small intestine I/R injury according to the pre-experimental results). Twelve mice were randomly divided into I/R-24 h-BMP4 group (recombinant human BMP4 protein was injected intraperitoneally), I/R-24 h-NS (normal saline) group (NS was injected intraperitoneally), and I/R-24 h-blank group (did nothing), 4 mice in each group. Then the small intestinal transmembrane electrical impedance (TER) was measured by Ussing chamber. The expressions of BMP4 protein and tight junction proteins (occludin and ZO-1), Notch signaling pathway proteins (Notch1 and Jagged1), and Smad6 protein were detected by Western blot. Results At 24 h after I/R injury, the injuries of villous epithelium, edema, and a small part of villi were alleviated. The BMP4 mRNA expressions at 6, 12, 24 and 48 h after I/R injury in the small intestinal epithelial cells were increased as compared with the SO group. Compared with the I/R-24 h-NS group and the I/R-24 h-blank group, the TER was increased, and the expression levels of occludin, ZO-1, p-Smad6, Notch1, Jagged1 were increased in the I/R-24 h-BMP4 group. Conclusion From the preliminary results of this study, during recovery period of small intestine I/R injury, the expression of BMP4 in small intestinal epithelial cells is increased, permeability of jejunal mucosal barrier is increased, which might promote the recovery of small intestinal mucosal barrier function by activating the Notch signaling pathway (Notch1 and Jagged1), Smad classic signaling pathway, and promoting the increase of tight junction protein expression (occludin and ZO-1).
【Abstract】 Objective To summarize the recent progress in related research on transforming growth factor β1 （TGF-β1）/Smad3 signal transduction pathway and post-traumatic scar formation. Methods Recent related literature at home and abroad on TGF-β1/Smad3 signal transduction pathway and post-traumatic scar formation was reviewed and summarized. Results TGF-β1 is an important influence factor of fibrotic diseases, and it plays biological effects by TGF-β1/Smad3 signal transduction pathway. The pathway is regulated by many factors and has crosstalk with other signal pathways at cellular and molecular levels. The pathway is involved in the early post-traumatic inflammatory response, wound healing, and late pathological scar formation. Intervening the transduction pathway at the molecular level can influence the process of fibrosis and extracellular matrix deposition. Conclusion TGF-β1/Smad3 signal transduction pathway is an important way to affect post-traumatic scar formation and extracellular matrix deposition. The further study on the pathway will provide a theoretical basis for promotion of wound healing, as well as prevention and treatment of pathological scar formation.
ObjectiveTo investigate the effect of Smad4 on the fibrosis of tendon derived fibroblasts (TDFs) induced by transforming growth factor β1(TGF-β1) by targeted regulation of miRNA219-5P (miR219-5P). MethodsThe tendons donated by the volunteers were harvested to isolate and culture TDFs. The 3rd generation cells were used for experiment. Chemically synthesized miR219-5P mimics, miR219-5P inhibitor, and negative control sequences were transfected into TDFs. The gene expression of miR219-5P in TDFs was detected by real-time PCR, and the protein expression of Smad4 in TDFs was detected by Western blot at 48 hours after transfection. The combining sites of miR219-5P and Smad4 in 3'UTR district were predicted by informatics software. Wild type and mutant type reporter gene expression vectors were constructed and then targeted verification was carried out by the luciferase reporter gene test. Transfected TDFs were then induced by TGF-β1. The proliferation activity of the cells were measured by the cell counting kit 8 after culturing for 24, 48, and 72 hours. The expressions of fibrosis related proteins in TDFs were detected by Western blot at 72 hours. ResultsAfter TDFs were transfected by miR219-5P mimics, miR219-5P expression was significantly up-regulated, but the expressions of Smad4 was decreased subsequently (P<0.05). Intracellular expression of miR219-5P was inhibited by miR219-5P mimics inhibitor, however, the protein expression of Smad4 was significantly increased (P<0.05). Luciferase reporter gene test showed that luciferase activities were significantly decreased in pGL3-WT-Smad4+mimics group, but were significantly increased in pGL3-WT-Smad4+inhibitor group when compared with pGL3-WT-Smad4 transfected group (P<0.05), but no significant difference was found between GL3-MT-Smad4+mimics and pGL3-MT-Smad4+inhibitor groups (P>0.05). Cell proliferation and the fibrosis related proteins were increased in TGF-β1 induced TDFs, however, decreased in TGF-β1 induced TDFs after transfected by miR219-5P inhibitor (P<0.01). ConclusionmiR219-5P can significantly inhibit fibrosis of TDFs induced by TGF-β1 by down-regulating Smad4 expression.
ObjectiveTo explore if Smad7 protein can inhibit growth of keloids by observing the gene and protein expressions of Smad7, collagen type Ⅰ, and collagen type Ⅲ and cell proliferation after over-expression vectors of Smad7 transfecting keloid fibroblasts (KFb). MethodsFibroblasts were acquired from 10 male patient with keloids at the age of 20 to 25 years. After in vitro culture, KFb were divided into 3 groups: untransfected group (group A), pcDNA3.1 (-) transfected group (group B), and pcDNA3.1 (-)-smad7 transfected group (group C). The mRNA and protein expression levels of Smad7, collagen type Ⅰ, and collagen type Ⅲ were detected by real-time fluorescence quantitative PCR and Western blot at 48 hours after transfection. The cell proliferation ability was detected by MTT assay at 24 hours after transfection. ResultsThe relative expression levels of mRNA and protein of Smad7 in group C were significantly higher than those in group A and group B (P < 0.01). The relative expression levels of mRNA and protein of collagen type Ⅰ and collagen type Ⅲ in group C were significantly lower than those in group A and group B (P < 0.01). The relative expression levels of mRNA of collagen type Ⅰ and collagen type Ⅲ in group B were significantly higher than those in group A (P < 0.01); and the relative expression levels of proteins of Smad7, collagen type Ⅰ, and collagen type Ⅲ were significantly lower than those in group A (P < 0.01). The cell proliferation ability in group C was significantly lower than that in group A and group B at each time point by MTT assay (P < 0.05), but no difference was found between group A and group B (P>0.05). ConclusionGene expressions of collagen type Ⅰ, and collagen type Ⅲ and cell proliferation will be inhibited after KFb are transfected by over-expression vector of Smad7.
Long non-coding RNA (lncRNA) Dnm3os plays a critical role in peritendinous fibrosis and pulmonary fibrosis, but its role in the process of cardiac fibrosis is still unclear. Therefore, we carried out study by using the myocardial fibrotic tissues obtained by thoracic aortic constriction (TAC) in an early study of our group, and the in vitro cardiac fibroblast activation model induced by transforming growth factor-β1 (TGF-β1). Quantitative real-time polymerase chain reaction (RT-qPCR), Western blot, and collagen gel contraction test were used to identify the changes of activation phenotype and the expression of Dnm3os in cardiac fibroblasts. Small interfering RNA was used to silence Dnm3os to explore its role in the activation of cardiac fibroblasts. The results showed that the expression of Dnm3os was increased significantly in myocardial fibrotic tissues and in the activated cardiac fibroblasts. And the activation of cardiac fibroblasts could be alleviated by Dnm3os silencing. Furthermore, the TGF-β1/Smad2/3 pathway was activated during the process of cardiac fibroblasts activation, while was inhibited after silencing Dnm3os. The results suggest that Dnm3os silencing may affect the process of cardiac fibroblast activation by inhibiting TGF-β1/Smad2/3 signal pathway. Therefore, interfering with the expression of lncRNA Dnm3os may be a potential target for the treatment of cardiac fibrosis.
OBJECTIVE: To clarify the mechanisms of the signal transduction of bone morphogenetic proteins (BMPs) inducing bone formation and to provide theoretical basis for basic and applying research of BMPs. METHOD: We looked up the literature of the role of Smads and related transcription factors in the signal transduction of BMPs inducing bone formation. RESULTS: The signal transduction processes of BMPs included: 1. BMPs combined with type II and type I receptors; 2. the type I receptor phosphorylated Smads; and 3. Smads entered the cell nucleus, interacted with transcription factors and influenced the transcription of related proteins. Smads could be divided into receptor-regulated Smads (R-Smads: Smad1, Smad2, Smad3, Smad5, Smad8 and Smad9), common-mediator Smad (co-Smad: Smad4), and inhibitory Smads (I-Smads: Smad6 and Smad7). Smad1, Smad5, Smad8, and probable Smad9 were involved in the signal transduction of BMPs. Multiple kinases, such as focal adhesion kinase (FAK), Ras-extracellular signal-regulated kinase (ERK), phosphatidylinositol 3-kinase (PI3K), and Akt serine/threonine kinase were related to Smads signal transduction. Smad1 and Smad5 related with transcription factors included core binding factor A1 (CBFA1), smad-interacting protein 1 (SIP1), ornithine decarboxylase antizyme (OAZ), activating protein-1 (AP-1), xenopus ventralizing homeobox protein-2 (Xvent-2), sandostatin (Ski), antiproliferative proteins (Tob), and homeodomain-containing transcriptian factor-8 (Hoxc-8), et al. CBFA1 could interact with Smad1, Smad2, Smad3, and Smad5, so it was involved in TGF-beta and BMP-2 signal transduction, and played an important role in the bone formation. Cleidocranial dysplasia (CCD) was thought to be caused by heterozygous mutations in CBFA1. The CBFA1 knockout mice showed no osteogenesis and had maturational disturbance of chondrocytes. CONCLUSION: Smads and related transcription factors, especially Smad1, Smad5, Smad8 and CBFA1, play an important role in the signal transduction of BMPs inducing bone formation.
The transforming growth factor-β1 (TGF-β1)/Smad3 signal pathway is related to mutiple physiological and pathological generation mechanism of human being. Up to date, however, the spacial and time information on the phosphorylated Smad3 is still unclear. In this study, the process of Smad3 phosphorylation was observed under the physiological state in the living cells. Firstly, the ECFP-Smad3-Citrine (Smad3 biosensor) fusion protein expression vector was constructed and identified. Then the Smad3 biosensor was transfected into 293T cells. The transfection efficiency and the expressions of fusion proteins were observed in 24 hours. Thirdly, Smad3 biosensor flurorescence resonance energy transfer (FRET) was observed with the inversion fluorescence microscope and measured by the MetaFlour FRET 4.6 software. Smad3 biosensor transfection efficiency was nearly 40% and the fusion protein was seen under the fluorescence microscope. The FRET ratio of Smad3 biosensor in living 293T cells was decreased after 10 minutes incubation with the ligand of TGF-β1. The period of decreasing CFP and enhancing Citrine signals was about 300 seconds. With the technology of FRET, the TGF-β1/Smad3 signal pathway could be real time monitored dynamically under the physiological condition in living cells.