Effects of Danshensu on TGF-β1/Smads signaling pathways in rats with pulmonary fibrosis

AIM: To study the preventive and curative roles of Danshensu (DA) in bleomycin (BLM)-induced pulmonary fibrosis in rats. METHODS: Pulmonary fibrosis was induced in SD rats by intratracheal instillation of BLM. The rats were intraperitoneally injected with dexamethasone (1 mg·kg-1·d-1, DXM group), DA (15 mg·kg-1·d-1, DA group), or physiological saline (2 mL·d-1, BLM group). Normal controls (NC group) received physiological saline both intratracheally and intraperitoneally. At the 28th day after modeling, the histological changes of the lungs were evaluated by hematoxylin-eosin (HE) and Masson’s trichrome staining. The protein levels of α-smooth muscle actin (α-SMA) in the lung tissues were detected by the method of immunohistochemistry. The mRNA expression of transforming growth factor beta 1 (TGF-β1), Smad3 and Smad7 was assessed by real-time fluorescence quantitative PCR. RESULTS: Compared with BLM group, the degree of inflammation and fibrosis of the lung in DA group was obviously reduced, and so was the expression of α-SMA in the lung tissues. The mRNA expression of TGF-β1 and Smad3 in the lung tissues of the rats decreased and the mRNA expression of Smad7 increased. CONCLUSION: DA alleviates BLM-induced pulmonary fibrosis in rats in the early stage by inhibiting the expression of TGF-β1/Smad3 and stimulating the expression of Smad7 in the lung tissues.     

VPA alleviates bleomycin-induced pulmonary fibrosis in rats

AIM: To investigate the effect of sodium valproate (VPA) on bleomycin-induced pulmonary fibrosis (PF) and its mechanism. METHODS: SD rats (n=42) were randomly divided into model group and treatment group. Bleomycin at dose of 5 mg/kg was intratracheally injected to establish a rat PF model. The rats in treatment group were given normal saline (NS, 0.5 mL/d), VPA (300 mg·kg^-1·d^-1) or dexamethasone (DEX, 0.6 mg·kg^-1·d^-1) via intraperitoneal injection from the 14th day to the 28th day after modeling. The rats in model group were sacrificed on 0 d, 14 day and 28 d after modeling . The rats in treatment group were killed at 14th day after treatment. The effects of VPA on PF were evaluated by HE and Masson staining. The hydroxyproline (HYP) content in the rat lung tissues was detected, and the expression of α-smooth muscle actin (α-SMA) and E-cadherin was determined by Western blotting. RESULTS: HE staining showed that the alveolar structure and interstitial morphology in VPA group were better than those in NS group and DEX group. The level of collagen in VPA group was significantly lower than that in DEX group and NS group by determining the HYP content and Masson staining. VPA reduced the expression of α-SMA, a mesenchymal marker protein of PF, while increased the expression of epithelial marker protein E-cadherin. CONCLUSION: VPA reduces collagen content and distribution, and up-regulates the expression of the epithelial marker protein E-cadherin, while down-regulates mesenchymal marker protein α-SMA, thereby preventing the rat lung tissues from bleomycin-induced PF.     

Imatinib attenuates DOCA/salt-induced rat myocardial fibrosis via PDGFs/PDGFRs signaling pathway

AIM：To investigate the role of imatinib (IMA) in reducing myocardial fibrosis and its relationship with platelet-derived growth factors (PDGFs)/PDGF receptors (PDGFRs) signaling pathway in deoxycorticosterone acetate (DOCA)/salt-induced hypertension in rats. METHODS:Sixty male uninephrectomized SD rats were treated with 1% NaCl and 0.2% KCl in the drinking water for 4 weeks and randomly divided into vehicle control (CON) group, DOCA treatment (DOCA) group and DOCA plus IMA treatment (DOCA+IMA) group. Systolic blood pressure (SBP) was mea-sured weekly using the tail-cuff method. The extent of myocardial interstitial fibrosis and the ratio of perivascular collagen area/vascular area (PVCA/VA) were analyzed by picro-Sirius red staining. The mRNA expression of fibroblast-specific protein 1 (FSP-1), α-smooth muscle actin (α-SMA), procollagenⅠ, procollagenⅢ, PDGFRα and PDGFRβ in the myocardium was measured by real-time PCR. The protein levels of PDGFRα, PDGFRβ, p-PDGFRβ, vimentin and α-SMA were analyzed by immunohistochemical staining. The cell types of PDGFRα and PDGFRβ localizations were examined by immunofluorescence method. RESULTS：(1) SBP in DOCA and DOCA+IMA groups was higher than that in CON group on day 14 and day 28, and no difference of SBP between DOCA group and DOCA+IMA group was found. The extent of myocardial interstitial fibrosis and the ratio of PVCA/VA in DCOA group were higher than those in CON group, and those in DOCA+IMA group were significantly lower than those in DOCA group on day 28. (2) Compared with CON group, the expression of PDGFRα and PDGFRβ in DOCA group was increased on day 14. Compared with DOCA group, the expression of PDGFRα and PDGFRβ in DOCA+IMA group was attenuated. Compared with CON group, the expression of PDGFRβ, p-PDGFRβ, FSP-1, α-SMA, procollagenⅠand procollagen Ⅲ in DOCA group was increased significantly on day 28, but the expression of PDGFRα was not increased significantly, and the expression of PDGFRβ was higher than PDGFRα. Compared with DOCA group, the expression of PDGFRβ, p-PDGFRβ, FSP-1, α-SMA, procollagenⅠand procollagen Ⅲ in DOCA+IMA group was attenuated on day 28. (3) The fibroblasts in the myocardial interstitium of CON group were mainly vimentin positive, but not α-SMA positive on day 28,while the number of α-SMA-positive spindle-shaped cells (myofibroblasts) increased significantly in DOCA group. Compared with DOCA group, the number of myofibroblasts in DOCA+IMA group was attenuated on day 28. (4) PDGFRα was located in fibroblasts and myofibroblasts but not in vascular smooth muscle cells (VSMCs). PDGFRβ was not only located in myofibroblasts but also in VSMCs. CONCLUSION:PDGFRα takes effect in the early phase of myocardial fibrosis in the DOCA/salt hypertensive rats, while PDGFRβ takes effect in the entire process. PDGFRα and PDGFRβ are expressed in cardiac fibroblasts and myofibroblasts. Imatinib reduces the proliferation and transformation of fibroblasts, thereby attenuating myocardial fibrosis by inhibiting PDGFs/PDGFRs signaling pathway.     

Effects of chloroquine on autophagy and collagen metabolism in activated hepatic stellate cells in vitro

AIM: To explore the effects of chloroquine (CQ) on collagen Ⅰand collagen Ⅲ expression in activated rat hepatic stellate cell line HSC-T6 and the possible mechanism.METHODS: Transforming growth factor-β1 (TGF-β1) was used to activate HSC-T6 cells and 3 doses of CQ was administered for 24 h. The cells were divided into 5 groups as follows:control group, TGF-β1 group, TGF-β1+CQ (15 μmol/L) group, TGF-β1+CQ (30 μmol/L) group and TGF-β1 + CQ (60 μmol/L) group. Western blot was used to determine the expression of LC3-Ⅱ/LC3-I, P62 and α-SMA in activated HSC-T6 cells. The expression of collagen I and collagen Ⅲ was detected by immunocytochemical staining, Western blot and RT-qPCR. Western blot and RT-qPCR were also used to detect the expression of matrix metalloproteinase-13 (MMP-13), tissue inhibitor of metalloproteinase-1 (TIMP-1) and TIMP-2 at mRNA and protein levels.RESULTS: The ratio of LC3-Ⅱ/LC3-Ⅰ and P62 expression were increased after CQ intervention. Moreover, they were significantly higher in the TGF-β1+CQ groups than those in TGF-β1 group (P<0.01). The expression of collagen I and collagen Ⅲ at mRNA and protein levels was significantly increased in all TGF-β1+CQ groups as compared with TGF-β1 group (P<0.01), and it was markedly increased among TGF-β1+CQ groups in a dose-dependent manner. The expression of MMP-13 at mRNA and protein levels was significantly lowered and that of TIMP-1 and TIMP-2 was significantly increased in TGF-β1+CQ groups as compared with TGF-β1 group (P<0.05).CONCLUSION: Inhibition of autophagy by CQ in activated HSC-T6 cells up-regulates the expression of collagen I and collagen Ⅲ in a dose-dependent way, probably due to reduction of MMP-13 and enhancement of TIMP-1 and TIMP-2 expression.     

Inhibitory effect of metformin on alveolar epithelial-mesenchymal transition in lung tissue of rats with pulmonary fibrosis

AIM: To study the inhibitory effect of metformin on alveolar epithelial-mesenchymal transition (EMT) in rats with pulmonary fibrosis and the possible mechanism. METHODS: SD rats (n=48) were used, 12 of which were set up as normal control group, and 36 of which were induced by bleomycin (5 mg/kg) by tracheal instillation to establish pulmonary fibrosis. The pulmonary fibrosis rats were randomly divided into bleomycin group, low dose (100 mg/kg) of metformin group, and high dose (300 mg/kg) of metformin group. The rats in metformin groups were given the corresponding dose of metformin daily for 4 weeks. HE staining and Masson staining were used to observe the changes of lung histopathology and collagen deposition. Real-time PCR, Western blot and innunohistochemical staining were used to detect the mRNA and protein expression of α-smooth muscle actin (α-SMA), E-cadherin, vimentin, zonula occludens-1 (ZO-1), collagen I, collagen III and transforming growth factor-β₁ (TGF-β₁), and the protein phosphorylation levels of Smad2/3 and extracellular signal-regulated kinase 1/2 (ERK1/2) were also determined. RESULTS: Metformin up-regulated the expression of E-cadherin and ZO-1, down-regulated the expression of α-SMA, vimentin, collagen I and collagen III, and the protein phosphorylation levels of Smad2/3 and ERK1/2 were also decreased (P<0.05). CONCLUSION: Metformin inhibits alveolar EMT in the rats with pulmonary fibrosis, and its mechanism may be related to the inhibition of TGF-β₁ signal transduction pathway.     

Role of TGFβ1/Smad3 signaling pathway-mediated lysine hydroxylase 2 activity in collagen deposition of pulmonary fibrosis

AIM: To investigate the effect of TGFβ1/Smad3 signaling pathway on the changes of lysyl hydro-xylase2 (LH2) activity, and to study the role in the relationship between LH2 and collagen deposition of pulmonary fibrosis. METHODS: Human lung fibroblast cell line HFL1 was cultured in F12 medium with 10% fetal bovine serum. The cells were divided into control group, TGFβ1 (10 μg/L) stimulation group, and minoxidil (5 μmol/L) intervention group. The cells in control group were treated with the equivalent volume of medium. The RNA and protein were collected after 48 h. The mRNA levels of PLOD2, α-SMA and COLⅠ were detected by RT-qPCR. The protein levels of LH2, total Smad3, phosphorylated Smad3, α-SMA, COLⅠ and COL Ⅳ were determined by Western blot. Hydroxylysylpyridinoline (HP) content was detected by ELISA. RESULTS: After stimulation with TGFβ1, the mRNA expression of PLOD2, α-SMA and COLⅠ was increased (P<0.01), and the protein levels of LH2, p-Smad3, α-SMA, COLⅠ and COL Ⅳ were also up-regulated, but the total Smad3 protein did not change. Treatment with minoxidil decreased the levels of above indexes (P<0.01). Compared with control group, stimulation with TGFβ1 increased the content of HP. However, treatment with minoxidil decreased the synthesis of HP (P<0.05). CONCLUTION: Activation of TGFβ1/Samd3 signaling pathway enhances LH2 expression. Minoxidil inhibits the TGFβ1/Samd3 signaling transduction, thereby reducing the expression of LH2 and the synthesis of hydroxylysyl collagen pyridine chain, and reducing pulmonary fibrosis.     

TAK1 regulates fibrosis of renal tubular epithelial cells by regulating p38 MAPK signaling pathway

AIM:To investigate the effect of transforming growth factor-β (TGF-β) activated kinase 1(TAK1) on renal tubular epithelial fibrosis. METHODS:The renal tubular epithelial cell line HK-2 was used as the research object. After induced by TGF-β1, real-time PCR and Western blot were used to detect the expression of TAK1 in the HK-2 cells. TAK1 shRNA lentivirus was used to infect HK-2 cells, real-time PCR and Western blot were used to determine the interference effect on TAK1 expression in the HK-2 cells with TGF-β1 stimulation. Under the condition of treating with p38 MAPK activator anisomycin, the levels of type I collagen and type Ⅲ collagen in the supernatant, and the protein levels of α-smooth muscle actin (α-SMA), connective tissue growth factor (CTGF) and p-p38MAPK^{Thr 180/Tyr 182} in the HK-2 cells with TAK1 knock-down were determined by ELISA and Western blot, respectively. RESULTS:TGF-β1 significantly increased the expression of TAK1 in the HK-2 cells(P<0.05). TAK1 shRNA significantly decreased the expression of TAK1 in the HK-2 cells with TGF-β1 stimulation. Type I collagen and type Ⅲ collagen secreted by the HK-2 cells after treatment with TGF-β1 were increased, the protein levels of α-SMA, CTGF and p-p38MAPK^{Thr 180/Tyr 182} were also increased(P<0.05). Knock-down of TAK1 expression significantly inhibited the secretion of type I and type Ⅲ collagen, reduced the protein levels of α-SMA, CTGF and p-p38MAPK^{Thr 180/Tyr 182} in the TGF-β1-induced HK-2 cells(P<0.05). Treatment with p38 MAPK activator reversed the inhibitory effect of TAK1 knock-down on the secretion of type I and type Ⅲ collagens, and the protein levels of α-SMA, CTGF and p-p38 MAPK^{Thr 180/Tyr 182} in the HK-2 cells(P<0.05). CONCLUSION:Knock-down of TAK1 expression attenuates the TGF-β1 induced fibrosis of renal tubular epithelial cells by inhibiting p38 MAPK signaling pathway.     

Sedum sarmentosum Bunge extract inhibits epithelial-mesenchymal transition and collagen accumulation in aristolochic acid-treated rat renal tubular epithelial cells

AIM:To investigate the effect of Sedum sarmentosum Bunge (SSB) extract on epithelial-mesenchymal transition (EMT) and collagen accumulation induced by aristolochic acid (AA) in renal tubular epithelial cells. METHODS:Rat renal tubular epithelial NRK-52E cells were randomly divided into 3 groups, including control group (only treated with solvent), AA group (treated with AA at concentrations ranging from 1 to 100 mg/L) and SSB group (treated with AA at a concentration of 10 mg/L plus SSB extract at concentrations ranging from 10 to 2 000 mg/L). After cultured for 24 h, the morphology of the NRK-52E cells was observed under inverted phase-contrast microscope. The level of transforming growth factor β1 (TGF-β1) in the culture supernatant was measured by ELISA. Immunofluorescent analysis was performed to detect the expression of epithelial marker α-smooth muscle actin (α-SMA), mesenchymal marker E-cadherin, and extracellular cell matrix component type III collagen. The mRNA expression of E-cadherin, α-SMA, bone morphogenetic protein 7 (BMP-7) and type I collagen was also quantified by real-time PCR. RESULTS: Fibrosis-like reaction observed under microscope was obviously increased in AA-treated NRK-52E cells, and aggravated as the increase in the concentration of AA. AA at concentrations of 1 and 10 mg/L increased the expression of α-SMA, type I and type III collagens, and decreased the expression of E-cadherin. With SSB extract treatment, fibrosis in NRK-52E cells was alleviated, accompanied with the decreasing expression of α-SMA, type I and type III collagen, and the enhancing expression of E-cadherin and BMP-7.Moreover, SSB extract down-regulated TGF-β1 level in a concentration-dependent manner. CONCLUSION: AA-induced fibrosis-like reaction in renal tubular epithelial cells is reduced by the treatment with SSB extract. The possible mechanism is that SSB extract decreases TGF-β1 level, and inhibits renal EMT and collagen accumulation induced by AA.［KEY WORDS］Sedum sarmentosum Bunge|Aristolochic acid|Transforming growth factor β1|Epithelial-mesenchymal transition|Collagen     

Effect of CKLF1-C19 polypeptide on differentiation of human lung fibroblast into myofibroblast induced by TGF-β

AIM: To investigate the effect of CKLF1-C19 polypeptide (C19) on differentiation of human lung fibroblast (LFB) into myofibroblast (MFB) induced by TGF-β. METHODS: LFBs were cultured and identified. LFBs were treated with TGF-β (5 μg/L) to establish the cell model of LFB differentiate into MFB. The LFBs were divided into 6 experimental groups including control group, TGF-β group, and TGF-β plus different doses (1, 0.1, 0.01, 0.001 mg/L) C19 groups. The cell morphology, cell proliferation rate, and the expression of α smooth muscle actin (α-SMA) and collagen I were observed. RESULTS: Human primary LFB was successfully cultured and was confirmed by the method of immunofluorescence. TGF-β at 5 μg/L induced proliferation and differentiation of LFB. The mRNA levels of α-SMA and collagen I in TGF-β group were higher than that in control group (P<0.05).The cell proliferation rates, mRNA levels of α-SMA and collagen I, and the protein expression of α-SMA in 0.01 mg/L+TGF-β group and 0.001 mg/L+TGF-β group were markedly lower than those in TGF-β group (P<0.05). CONCLUSION: C19 at 0.01 mg/L and 0.001 mg/L effectively inhibits differentiation of LFB into MFB induced by TGF-β, thus inhibiting the process of airway remodeling and fibrosis to some extent.     

Chronic alcohol intake-induced epithelial-mesenchymal transition contri-butes to hepatic fibrogenesis in mice

AIM：To evaluate the effect of chronic alcohol intake on the histopathological changes of the liver and to determine the contribution of epithelial-mesenchymal transition (EMT) to hepatic fibrogenesis. METHODS：Thirty male C57BL/6 mice were randomly divided into 3 groups as following: the mice in control group was given (ig) water; the mice in low-dose alcohol group (2.0 g·kg -1·d -1) and high-dose alcohol group (4.0 g·kg -1·d -1) were given (ig) alcohol for 5 months. Alcohol-induced histopathological changes of the liver or development of hepatic fibrosis were evaluated using the histological methods with HE and Masson trichrome staining. The apoptosis of the liver was detected by TUNEL fluorometric staining (counterstained with DAPI). The activity of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) was measured by an automated biochemical analyzer. The expression of fibroblast-specific protein 1 (FSP-1), α-smooth muscle actin (α-SMA) and E-cadherin in the hepatic tissues was detected by immunofluorescence examination. The protein levels of E-cadherin, α-SMA, FSP-1, transforming growth factor β 1 (TGF-β 1) and hypoxia-inducible factor 1α (HIF-1α) were analyzed by Western blotting. RESULTS：Compared with control, the activity of serum ALT and AST, and apoptotic index of liver tissues were increased in the mice treated with alcohol for 5 months. The histopathological changes of the livers in the mice of low-dose alcohol group included steatosis and mild liver fibrosis, while severe liver fibrosis was observed in the high-dose alcohol-treated mice. Chronic alcohol consumption induced the increase in malondialdehyde (MDA) level, and the decreases in the activity of superoxide dismutase (SOD) and catalase (CAT) in the livers. It also reduced E-cadherin expression and increased α-SMA expression. FSP-1 immunostaining and albumn immunostaining positive cells were co-localized in the hepatocytes of low-dose alcohol group, but only FSP-1 positive hepatocytes were observed in high-dose alcohol group. Chronic alcohol consumption decreased E-cadherin expression and increased α-SMA, FSP-1, TGF-β 1 and HIF-1α expression in a dose-dependent manner, but the HIF-1α expression was not altered between the 2 alcohol-treated groups. CONCLUSION：Chronic alcohol intake induces the progression of hepatic fibrosis. Some fibroblasts derive from hepatocytes in liver fibrosis via EMT. The underlying mechanism is associated with the changes of the redox state, and increased TGF-β 1 generation and HIF-1α expression.     

Changes of histone modification levels in rats with liver fibrosis

AIM: To observe the changes of histone modifications in the liver of rats with hepatic fibrosis and its possible role in the development of hepatic fibrosis. METHODS: Male Wistar rats (n=20) were randomly divided into liver fibrosis group and normal control group. The liver fibrosis model was established by hypodermic injection of CCl₄, and the rats in normal control group were injected with vegetable oils. At the end of the 8th week, all rats were killed. Liver function indexes including alanine aminotransferase (ALT) and aspartate aminotransferase (AST), and liver fibrosis indexes including haluronic acid (HA), laminin (LN), collagen type IV (Col Ⅳ) and procollagen type Ⅲ (PCⅢ) were determined by biochemical and RIA methods. The liver index was analyzed, and the liver fibrosis degree and the morphological change of the liver were detected by HE and Masson staining. The levels of α-smooth muscle actin (α-SMA), collagen type Ⅰ (ColⅠ), H3K4me2, H3K9me2, acH3K9 and acH4K12 were detected by Western blot. RESULTS: After hypodermic injection of CCl₄ for 8 weeks, the liver index, ALT, AST, HA, LN, Col Ⅳ and PCⅢ of the rats in liver fibrosis group were higher than those in control group (P<0.05). Compared with control group, the level of acH4K12 was decreased (P<0.05), while acH3K9, H3K9me2, α-SMA and ColⅠ were increased (P<0.05), but H3K4me2 had no significant change.CONCLUSION: The levels of acH4K12, acH3K9 and H3K9me2 may play essential roles in the pathogenesis of liver fibrosis, and these histone modifications may regulate gene expression associated with extracellular matrix metabolism.     

Inhibitory effect of oxymatrine on high glucose-induced rat renal tubular epithelial-mesenchymal transition

AIM:To investigate the inhibitory effect of oxymatrine (OM) on high glucose-induced rat renal tubular epithelial-mesenchymal transition (EMT). METHODS:The rat renal tubular epithelial NRK52E cells were cultured in vitro. The cells were divided into control group, high glucose group, high glucose+different concentrations of OM groups and high glucose+0.50 g/L OM dynamic observation group. The expression of TGF-β1, Smad7, α-SMA and E-cadherin at mRNA and protein levels was detected by real-time PCR and Western blotting. The viability of NRK52E cells was determined by MTT assay. RESULTS:(1) Compared with control group, the expression of TGF-β1 and α-SMA at mRNA and protein levels in high glucose group gradually increased, and Smad7 protein and E-cadherin mRNA and protein gradually reduced, but the mRNA expression of Smad7 gradually increased. (2) Compared with high glucose group, as increases in OM doses, the expression of TGF-β1 and α-SMA at mRNA and protein levels in high glucose+different concentrations of OM groups gradually reduced, and Smad7 protein and E-cadherin mRNA and protein gradually increased, but the mRNA expression of Smad7 had no significant change. (3) Compared with high glucose group, the expression of TGF-β1 and α-SMA at mRNA and protein levels was significantly reduced, the expression of E-cadherin at mRNA and protein levels significantly increased, and the protein expression of Smad7 significantly increased, but the mRNA expression of Smad7 had no significant change in high glucose+0.50 g/L OM dynamic observation group. CONCLUSION: In NRK52E cells, oxymatrine inhibits high glucose induced EMT by down-regulating TGF-β1 and up-regulating Smad7, thus preventing the fibrosis effect of TGF-β1/Smads signaling.     

Effect of leonurine on expression of miR-1 in rats with myocardial fibrosis induced by isoproterenol

AIM: To investigate effect of leonurine on the expression of microRNA-1 (miR-1) in rats with myocardial fibrosis induced by isoproterenol (ISO). METHODS: SD rats (n=10) were used as normal control group, and 80 rats were given ISO by intraperitoneal injection daily for 2 weeks to establish the model of myocardial fibrosis. The model rats were randomly divided into 5 groups:model group, low-dose (7.5 mg·kg^-1·d^-1) leonurine group, middle-dose (15 mg·kg^-1·d^-1) leonurine group, high-dose (30 mg·kg^-1·d^-1) leonurine group and p38 mitogen-activated protein kinase (p38 MAPK) inhibitor (0.3 mg·kg^-1·d^-1) group. After the treatment for 2 weeks, the ultrastructure of left ventricular myocardial tissues was observed under electron microscope. Masson staining was used to detect collagen fibrosis, and the expression of collagen I and collagen Ⅲ was determined by the method of immunohistochemistry. The contents of endothelin-1 (ET-1) and angiotensin Ⅱ (Ang Ⅱ) were measured by ELISA. The expression of miR-1 and ET-1 mRNA was detected by real-time PCR, and the protein expression of p38 MAPK, β-myosin heavy chain (MHC) and α-MHC was determined by Western blot. RESULTS: Compared with model group, the ultrastructure of left ventricular myocardial tissues in high-dose leonurine group was attenuated, and the expression of miR-1 and the protein expression of α-MHC in left ventricular myocardial tissues of high-dose leonurine group were increased (P<0.05). Collagen volume fraction, collagen I, collagen Ⅲ, the ratio of collagen Ⅰ/collagen Ⅲ, the contents of ET-1 and Ang Ⅱ, the mRNA expression of ET-1, and the protein expression of p38 MAPK and β-MHC in high-dose leonurine group were lower than those in model group (P<0.05). CONCLUSION: Leonurine attenuates myocardial fibrosis in the rats induced by ISO, and it is potentially associated with affecting the expression of miR-1, and inhibiting ET-1/p38 MAPK signaling pathway.     

Lentiviral vector CV072-mediated Mfn2 over-expression inhibits hepatic stellate cell activation

AIM:To construct a lentiviral vector carrying mitofusin 2 (Mfn2), and to investigate the inhibitory effect of Mfn2 on the activation of rat hepatic stellate cells and its mechanism of reducing the formation of hepatic fibrosis-related factors. METHODS:The lentiviral over-expression vector CV072-pCMV-Mfn2-EGFP containing Mfn2 was constructed and transfected into the hepatic stellate cells. The expression of green fluorescent protein was observed under fluorescence microscope, and the transfection efficiency was evaluated. The protein levels of Bax, Bcl-2, cleaved caspase-3, α-SMA, TGF-β1, Smad2 and Smad3 were detected by Western blot. The levels of type I collagen, type Ⅲ collagen and type IV collagen in the cell culture supernatants were determined by ELISA. RESULTS:Compared with control group, the apoptosis of the hepatic stellate cells transfected with lentivirus over-expression vector CV072-pCMV-Mfn2-EGFP was increased, and the protein levels of proapoptotic molecules Bax and cleaved caspase-3 were increased (P<0.01). TGF-β1/Smad pathway-related proteins TGF-β1, p-Smad2 and p-Smad3 were decreased, and the levels of fibrosis-related proteins α-SMA, type I collagen, type Ⅲ collagen and type IV collagen were decreased (P<0.01). CONCLUSION:Transfection of lentiviral over-expression vector CV072-pCMV-Mfn2-EGFP effectively inhibits hepatic stellate cell activation in vitro and may reduce the production of hepatic fibrosis-related factors by inhibiting TGF-β1/Smad pathway.     

Up-regulation of miR-181a attenuates releases of CSE-induced pro-inflammatory factors and expression of collagen IV,fibronectin and α-SMA in human bronchial epithelial cells

AIM: To investigate the effect and potential mechanism of microRNA-181a (miR-181a) on cigarette smoke extract (CSE)-induced the productions of pro-inflammatory factors and the expression of collagen IV, fibronectin and α-smooth muscle actin (α-SMA) in human bronchial epithelial cells (HBECs). METHODS: CSE-induced miR-181a expression was detected by RT-qPCR in the HBECs. After tansfected with miR-181a mimic, the releases of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β), IL-6 and transforming growth factor-β1 (TGF-β1) were measured by ELISA, the protein expression of collagen IV, fibronectin and α-SMA was determined by Western blot. The activation of NF-κB/TGF-β1/Smad3 pathway was also evaluated by Western blot. RESULTS: CSE increased the levels of TNF-α, IL-1β, IL-6 and TGF-β1 and the expression of collagen IV, fibronectin and α-SMA, and decreased the expression of miR-181a in the HBECs (P<0.05). However, transfected with miR-181a mimic partially prevented the releases of TNF-α, IL-1β, IL-6 and TGF-β1, and inhibited the expression of collagen IV, fibronectin and α-SMA (P<0.05). Additionally, the activation of NF-κB/TGF-β1/Smad3 evoked by CSE was attenuated after transfected with miR-181a mimic. CONCLUSION: Up-regulation of miR-181a prevents the releases of CSE-induced pro-inflammatory factors and expression of collagen IV, fibronectin and α-SMA in the HBECs, and its mechanism may be related to the inhibition of NF-κB/TGF-β1/Smad3 pathway.     

Intervention effects of apyrase on silica-induced pulmonary fibrosis in mice

AIM: To investigate the effect of apyrase on the experimental silicosis. METHODS: C57BL/6 male mice were randomly divided into control group, silica treatment group, silica+apyrase group and silica+NS group. A mouse model of lung fibrosis was induced by crystalline silica particles (50 mg/kg, via oropharyngeal instillation), and were sacrificed at 3 h, 7 d, 14 d and 28 d. Apyrase was delivered by oropharyngeal aspiration at the same time and 4 h after silica challenge. The lung indexes were calculated and the concentration of ATP was detected by bioluminescent assay. The mRNA expression levels of collagen type Ⅰ(Col Ⅰ), collagen type Ⅲ (Col Ⅲ) and transforming growth factor β1 (TGF-β1) were examined by real-time PCR. The protein levels of TGF-β1 in bronchoalveolar lavage fluid were measured by ELISA. RESULTS: The elevated lung index and collagen levels showed that silicosis model was established successfully. Compared with silica group, apyrase treatment significantly alleviated silica-induced inflammation, reduced inflammation score on day 7, and decreased the lung index, collagen volume fraction and the mRNA expression of Col Ⅰand Col Ⅲ on day 28. Treatment with apyrase effectively down-regulated the mRNA levels of TGF-β1 in the lung tissues and TGF-β1 protein levels in bronchoalveolar lavage fluid on day 7.CONCLUSION: Apyrase attenuates the pulmonary inflammation and fibrosis of silicosis, which may be related with down-regulation of ATP and TGF-β1 in the lung tissues.     

Regulation of rat pulmonary fibroblasts differentiation into myofibroblasts though RhoA/ROCK pathway mediated by TGF-β1

AIM：To investigate the regulatory effect of RhoA/Rho-associated coiled-coil-forming protein kinase (ROCK) pathway mediated by transforming growth factor β1 (TGF-β1) on the differentiation of pulmonary fibroblasts into myofibroblasts. METHODS：Primarily cultured fibroblasts were obtained by trypsin digestion from the lung of neonatal rats. The fibroblasts were stimulated with TGF-β1 for different durations and were divided into control group, TGF-β1 induction group and Y-27632 treatment group. The distribution and expression of p-RhoA, ROCK, phosphorylated myosin binding subunit of myosin light chain phosphatase (p-MBS), serum response factor (SRF), α-smooth muscle actin (α-SMA),type I collagen and type Ⅲ collagen in the cells were detected by the methods of immunocytochemistry and Western blotting. RESULTS：A lot of parallel and cross arranged filaments labeled by α-SMA antibody appeared in the cells after TGF-β1 stimulation. The cultured cells stimulated with TGF-β1 were all myofibroblasts at 24 h determined by immunocytochemistry. The expression levels of p-RhoA, ROCK, p-MBS, SRF, α-SMA and type I and type III collagens were increased gradually with the extension of TGF-β1 stimulation time. The expression of RhoA/ROCK signaling protein in the cells stimulated with TGF-β1 (peaking at 6 h of exposure) was 2.96 folds higher as compared with the non-stimulated cells. The expression of SRF protein (peaking at 12 h of TGF-β1 exposure) was 4.55 folds higher as compared with the non-sti-mulated cells. The expression levels of α-SMA and type I and type III collagens (peaking at 24 h of TGF-β1 exposure) were 4.06 folds, 2.19 folds and 3.04 folds higher as compared with the non-stimulated cells, respectively. Compared with TGF-β1 induction group, the protein expression levels of ROCK, p-MBS, SRF, α-SMA and type I and type III collagens were significantly decreased at the corresponding time points in Y-27632 treatment group. CONCLUSION：TGF-β1 induces the differentiation of pulmonary fibroblasts into myofibroblasts, and then promotes the synthesis of collagen through the activation of ROCK pathway, which possibly plays an important role in the formation of pulmonary fibrosis.     

Pirfenidone inhibits TGF-β1-induced differentiation of myofibroblast in human lung fibroblast populations

ATM: To investigate the effect of pirfenidone on transforming growth factor-β1 (TGF-β1)-induced fibroblast-to-myofibroblast transition in vitro. METHODS: The cell viability was measured by MTT assay. The proliferation of human lung fibroblasts (HLFs) was detected by EdU incorporation. Migratory and invasive abilities were measured by Boyden chamber assay. The α-smooth muscle actin (α-SMA) protein expression was determined by Western blot and immunofluorescence. The mRNA expression of α-SMA and type Ⅰ and Ⅲ collagens was evaluated by RT-qPCR. RESULTS: Pirfenidone at different concentrations (0.1, 0.2, 0.3, 0.5 and 0.8 mg/L) had no cytotoxic effect on the HLFs, and pirfenidone at 0.2 mg/L was used for the intervention. Pretreatment of the HLFs with 0.2 mg/L pirfenidone prior to TGF-β1 not only markedly suppressed the changes of proliferation, migration, invasion and reorganization of actin cytoskeleton in the HLFs (P<0.01﹚,but also down-regulated the expression of α-SMA and type C and Ⅲ collagens triggered by TGF-β1 ﹙P<0.05﹚.CONCLUSION: Pirfenidone has an inhibitory effect on TGF-β1-induced activated cell functions and fibroblast-to-myofibroblast transition in HLFs.     

Effect of angiotensin-(1-7) on angiotensin II-induced rat renal interstitial fibroblast activation

AIM: To explore the influence of angiotensin-(1-7) on angiotension II (Ang II)-induced activation and extracellular matrix secretion in rat renal interstitial fibroblasts (NRK-49F cells). METHODS: The NRK-49F cells were maintained and sub-cultured, then the cells were divided into control group, Ang II group, Ang-(1-7) group and Ang II+Ang-(1-7) group. The expression of α-smooth muscle actin(α-SMA),transforming growth factor β₁ (TGF-β₁) and insulin-like growth factor I(IGF-I) was detected by the method of immunocytochemistry when the cells were cultured for 72 h. The content of TGF-β₁, IGF-I and collagen type I(Col I) in the cultured supernatants were measured by ELISA. RESULTS: In control group and Ang-(1-7) group, only basic expression of α-SMA and almost no expression of TGF-β₁, IGF-I and Col I were observed. Compared with control group, the expression of α-SMA, TGF-β₁, IGF-I and Col I was increased in Ang II group. Compared with Ang II group, the expression of α-SMA, TGF-β₁, IGF-I and Col I was significantly decreased in Ang II+Ang-(1-7) group.CONCLUSION: Ang-(1-7) inhibits the activation of renal interstitial fibroblasts and decreases the Ang II induced secretion of Col I by suppressing TGF-β₁ and IGF-I expression.