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Objective To observe the effect of curcumin on the expression of smad7 and TGF-β1 in rats renal tubular cells of with Ang II, and discuss the mechanism of curcumin to improve renal interstitial fibrosis.Methods Cultured rat renal tubular epithelial cells were divided into the blank group, the Ang II control group and the low, medium and high dose curcumin group. The rest of the groups were intervened by 10-8 mol/L Ang II except the blank group; the low, medium and high dose groups of curcumin were intervened by 2.5, 5.0, 10.0μmol/L curcumin. Then Western blot was used to detect the expression of TGF-β1 and smad7 protein, RT-PCR was used to detect the TGF-β1 and smad7 mRNA expression.Results Compared with the blank group, the expression of TGF-β1 protein (0.23 ± 0.03vs. 0.16 ± 0.01), and TGF-β1 mRNA (1.89 ± 0.20vs. 1.00 ± 0.00) significantly increasedin AngⅡ control group (P<0.05), and the expression of smad7 protein (0.19 ± 0.03vs. 0.24 ± 0.02), and smad7 mRNA (0.48 ± 0.05vs. 1.00 ± 0.00) significantly reduced in AngⅡcontrol group (P<0.05). Compared with the AngⅡ control group, the expression of TGF-β1 protein in low, medium and high dose curcumingroup (0.18 ± 0.02, 0.17 ± 0.02, 0.16 ± 0.03vs. 0.23 ± 0.03) and TGF-β1 mRNA (1.58 ± 0.11, 1.34 ± 0.16, 0.97 ± 0.19vs. 1.89 ± 0.20) significantly decreased (P<0.05), and the expression of smad7 protein (0.28 ± 0.04, 0.31 ± 0.03, 0.34 ± 0.04vs. 0.19 ± 0.03) and smad7 mRNA (0.68 ± 0.07, 0.80 ± 0.06, 0.98 ± 0.09vs.0.48 ± 0.05) increased significantly (P<0.05).Conclusions Curcumin can thus play its role in renal protection by counteract the AngⅡ mediated renal interstitial fibrosis. Its mechanism may be related to the reduction of TGF-β1 protein and its mRNA expression, up regulation of smad7 protein and its mRNA expression.
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Objective To investigate the role of microRNA-21(miR-21) on cardiac fibroblast proliferation and dif-ferentiation in the mouse model of myocardial infarction. Methods The mouse model of myocardial infarction (MI) was es-tablished by ligation of the left coronary artery in male C57BL/6 mice(MI group). The echocardiographic assessment and his-tological evaluation were performed after ligation. The expression levels of miR-21 were measured by quantitative real-time PCR in the various myocardial tissues. The cardiac fibroblasts transfected with miR-21 mimic were over-expressed miR-21. The proliferation was assessed by immunostaining for 5-ethynyl-2’-deoxyuridine (EdU). Western blot assay was used to detect the expression ofα-SMA and Smad7 in the cardiac fibroblasts,and compared with control group and blank group. Results The expression of miR-21 was significantly increased in border area in MI group than that of sham group [(6.043 ± 0.231)×10-4 vs(1.620±0.451)×10-4,P<0.01]. There was a higher expression of miR-21 in miR-21 mimic group than that of control group and blank group [(4.839±0.705)×10-4 vs(1.143±0.064)×10-4 vs(1.017±0.201)×10-4,P<0.01]. The EdU positive rate was significantly higher in miR-21 mimic group than that of control group and blank group[(27.892±1.645)%vs(12.553 ± 1.227)% vs(13.946 ± 1.550)%,P<0.01]. The expression of α-SMA was significantly increased in miR-21 mimic group, while the expression of Smad7, a target gene of miR-21, was significantly decreased. Conclusion The over-expression of miR-21 in cardiac fibroblasts disrupts TGF-βsignaling pathway by reducing the expression of Smad7, which promotes the proliferation and differentiation of cardiac fibroblast, and finally regulates cardiac remodeling after myocardial infarction.
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Objective To investigate the expression and significance of Smad4 and Smad7 in newborn rats with hyperoxia-induced chronic lung disease(CLD).Methods Sixty-four newborn Wistar rats 12 h after birth were divided into high-oxygen group (n =32) and air group (n =32,control group) by random number table method.The high-oxygen group was placed in the oxygen glass tank with continuous infusion of oxygen.And 1,3,7,14 d after experiment,tracheal separated,the chest opened to expose heart and lung,slices were Masson staining,undergo dynamic observation of the pulmonary pathological changes under light microscope.Lung fibrosis score was carried out to determine the degree of pulmonary fibrosis,and immunohistochemical technique was used to detect Smad4 and Smad7 protein expression in lung tissue.The expression levels of Smad4 and Smad7 protein in lung tissue were detected with Western blot.Results Compared with the air group,there was statistically significant difference in pulmonary fibrosis score on day 7 (2.67 ± 0.21 vs 0.58 ± 0.17) and day 14 (4.48 ± 0.24 vs 0.63 ± 0.13) in high-oxygen group (P ＜ 0.05) ; Smad4 and Smad7 was main in visible lung epithelial cells and interstitial fibroblasts.Smad4 expression in the high-oxygen group gradually enhanced,compared with the air group (P ＜ 0.05) on day 7 (122.35 ± 10.3 vs 140.08 ±7.77) and day 14(129.7 ± 7.33 vs 144.99 ± 6.49).Smad7 expression in the high-oxygen group first increased and then decreased,expression in the high-oxygen group increased on day 7 (122.35 ± 10.29 vs 130.56 ±9.8),and compared decreased with the air group(P ＜0.05) on day 14(132.16 ±4.38 vs 126.22 ±6.49).Conclusion The newborn rat exposed hyperoxia,the up-regulation of Smad4 protein expression and the down-regulation of Smad7 protein expression are imposible closely related to the happen and development of CLD pulmonary fibrosis.
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Idiopathic pulmonary fibrosis (IPF) is a lethal parenchymal lung disease characterized by myofibroblast proliferation. Alveolar epithelial cells (AECs) are thought to produce myofibroblasts through the epithelial to mesenchymal transition (EMT). Receptor for advanced glycation end products (RAGE) is a member of the immunoglobulin superfamily of cell surface receptors whose activation is associated with renal fibrosis during diabetes and liver fibrosis. RAGE is expressed at low basal levels in most adult tissues except the lung. In this study, we evaluated the interaction of ligand advanced glycation end products (AGE) with RAGE during the epithelial to myofibroblast transition in rat AECs. Our results indicate that AGE inhibited the TGF-beta-dependent alveolar EMT by increasing Smad7 expression, and that the effect was abolished by RAGE siRNA treatment. Thus, the induction of Smad7 by the AGE-RAGE interaction limits the development of pulmonary fibrosis by inhibiting TGF-beta-dependent signaling in AECs.
Subject(s)
Animals , Rats , Epithelial Cells/cytology , Epithelial-Mesenchymal Transition/drug effects , /genetics , Idiopathic Pulmonary Fibrosis/metabolism , Pulmonary Alveoli/cytology , RNA, Small Interfering/genetics , Receptors, Immunologic/genetics , Smad7 Protein/genetics , Transforming Growth Factor beta/geneticsABSTRACT
Objective To study the protective mechanism of astragaloside on skin photoaging. Methods BALB/c mice were randomly divided into four groups: model group irradiated with ultraviolet rays (UV), model plus matrix group pretreated with the matrix before UV irradiation, model plus astragaloside group pretreated with astragaloside 0.08% cream before UV irradiation, normal control group received no irradiation or pretreatment. After 4-week irradiation, the mice were sacrificed, and skin tissues were resected from the back of these mice. Then, reverse transeription PCR (RT-PCR) and immunohistochemistry were performed to detect the mRNA and protein expression of TGF-βR Ⅱ and Smad 7, respectively. Gray scale ratio was used to represent the mRNA levels of TGF-βR Ⅱ and Smad 7. Results There was a significant difference in the mRNA level (F = 80.98, 736.80, respectively, both P 0.01). Conclusion Astragaloside can prevent skin photoaging by the alteration of TGF-β pathway via up-regulating TGF-βR Ⅱ expression and down-regulating Smad 7 expression.
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Objective To investigate the role of overexpression of Smad7,the inhibitory factor of TGF-?/Smads signaling,in epithelial-mesenchymal transition (EMT) of peritoneal mesothelial cells.Methods Peritoneal fibrosis rat model was built by daily intraperitoneal injection with 4.25% Dineal (100 ml/kg) and lipopolysaccharide(LPS) (0.6 mg/kg) at day 8,10,12,22,24,26. Smad7 or control empty vectors was transferred at day 0,14 and was induced by doxycline in the daily drinking water (200 mg/L).Rats were sacrificed on day 28 and the expression of TGF-beta/ Smads,?-SMA and E-cadherin was examined.Results Compared with normal rats,empty vector rats showed higher expression of phosphorylated Smad2/3.?-SMA expression was elevated but E-cadherin was reduced.Under electron microscope,the mesothelial cells removed to submesothelial zone and showed large bundles of actin microfilaments and dense bodies within the cytoplasm. Basement membrane was broken.After induction of Smad7 in peritoneal fibrosis rats,the morphology of mesothelial ceils normalized partly,phosphorylated Smad2/3 was reduced.Moreover,expression of E-cadherin was increased,expression of?-SMA was dramatically reduced.Conclusion Inhibition of TGF-?/Smad signaling by Smad7 overexpression may inhibit the epithelial-mesenchymal transition of mesothelial cell,which may provide a new therapeutic method for peritoneal fibrosis by overexpression of Smad7.
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Objective To construct,express,purify,identify and label the TAT-Smad7-HA fusion protein (protein transduction domain of trans-activator,human Smad7 and hyaluronic acid) and to validate its transduction activity in the cultured human primary keloid fibroblast cells. Methods TAT-PTD,Smad7 and HA fragments were sequentially inserted into pET32a(+) to construct the pTAT-Smad7-HA prokaryotic expression vector. After the expression of target fusion protein was induced to express by IPTG,affinity purification,Western blot analysis,enterokinase cleavage,target protein capture and FITC labeling were subsequently performed by turns to obtain the FITC-TAT-Smad7-HA fusion protein and to further observe its transduction activity in the human primary KFB cells in vitro. Results The prokaryotic expression vector for the TAT-Smad7-HA fusion protein,named as pTAT-Smad7-HA was successfully constructed,and the target fusion protein was efficiently induced to express,covering more than 25% of the total bacterial proteins,successfully purified with a purity of more than 95% purity,desalted by desalting column,identified by Western blotting,thioredoxin removed and FITC labeled. Finally,a fusion protein of FITC-TAT-Smad7-HA with the approximately molecular weight of 50?103 was successfully purified and its high transduction activity in KFB cells was validated. Conclusion The highly-purified FITC-TAT-Smad7-HA fusion protein and the validation of its high transduction activity in KFB cells have provided an experimental foundation for further studies on the role the human Smad7 protein playing in the TGF-?/Smads signal transduction pathway and further elucidation of the pathogenesis of keloid formation.