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.     

Increased fucosyltransferase 8 expression in rat kidney with unilateral ureteral obstruction

AIM: To investigate the effect of fucosyltransferase 8 (FUT8) on rat renal interstitial fibrosis induced by unilateral ureteral obstruction (UUO). METHODS: Ninety male Wistar rats were randomly divided into normal control group (control), sham operation group (sham) and UUO group, and sacrificed on day 1, 3, 7, 14 and 21 after operation. Serum creatinine and urea nitrogen were detected to assess renal function. PAS and Masson staining were used to observe histological changes of the rat kidneys. The time-correlated expression of FUT8 in the kidney was monitored by RT-PCR and Western blotting. The protein expression levels of FUT8 and activin receptor-like kinase 5(ALK5) were determined by immunofluorescence double-staining. Immunohistochemical staining was also used to assess the protein expression of fibronectin (FN), type I collagen (Col I) and α-smooth muscle actin (α-SMA). RESULTS: Compared with control group, serum creatinine and urea nitrogen in UUO group elevated on day 3 after operation (P<0.05) and reached the peak value on day 21 after operation (P<0.01). Renal tubule atrophy and renal interstitial fibrosis were observed in UUO group 7 and 14 days after operation. The mRNA and protein expression levels of FUT8 increased markedly in UUO group on day 3 (P<0.05) and reached its peak value on day 14 and 21 after operation (P<0.01). The results of immunofluorescence and immunohistochemistry showed that FUT8 and ALK5 were coexpressed in renal tubulointestitium. FN, Col I and α-SMA were significantly elevated in UUO group (P<0.05), and were positively correlated with the expression of FUT8 (P<0.05).CONCLUSION: The expression of FUT8 influences the progress of renal interstitial fibrosis, tubule atrophy and inflammatory cell infiltration in the kidney.     

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.     

Placental growth factor is involved in angiotensin II-induced cardiac fibroblast activation

AIM：To explore the role of placental growth factor (PLGF) in the process of angiotensin II (Ang II)-induced activation of cardiac fibroblasts (CFs). METHODS：Primary culture and identification of CFs from neonatal Sprague-Dawley rats were performed. The method of fluorescence immunocytochemistry was employed to observe the expression of alpha-smooth muscle actin (α-SMA). Real-time PCR and Western blotting were used to determine mRNA and protein levels. The cell proliferation was observed by WST-1 assay. RESULTS：Compared with control group, the PLGF expression at mRNA and protein levels in Ang II-treated CFs was significantly increased, whereas the mRNA expression of PLGF was decreased in the CFs treated with telmisartan and Ang II. Treatment with PLGF induced the proliferation of CFs and increased the protein expression of α-SMA. Treatment with PLGF for 60 min significantly increased the protein levels of p-ERK1/2 in the CFs. Compared with Ang II group, the proliferation of CFs was depressed and the protein expression of α-SMA was attenuated in Ang II+anti-PLGF group.The mRNA expression levels of type I and type III collagens were also down-regulated. CONCLUSION：PLGF might be involved in the process of Ang II-induced proliferation of CFs and fibrosis.     

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.     

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.     

Relationship between peritubular capillary injury and renal interstitial fibrosis in mice with unilateral ureteral obstruction

AIM: To observe the injury of peritubular capillary (PTC), hypoxia and interstitial fibrosis after unilateral ureteral obstruction (UUO), and to explore the effects of PTC injury and hypoxia on interstitial fibrosis in mouse model of UUO. METHODS: Forty-eight male KM mice were randomly divided into control group and UUO group. On the 1st, 3rd, 7th and 14th days, 6 mice in each group were sacrificed. The changes of pathomorphism in the kidney were observed by HE and Masson staining. The expression levels of thrombospondin-1 (TSP-1), vascular endothelial growth factor (VEGF) and hypoxia-inducible factor-1α (HIF-1α), and PTC density were detected by immunohistochemistry. The protein expression of VEGF was also determined by Western blotting. RESULTS: No histological abnormalities of the kidneys were observed in sham-operated mice. The expression of TSP-1 was increased 1 day after UUO, and significantly increased on the 3rd, 7th and 14th days(P<0.05). The expression of VEGF was obviously decreased(P<0.05). PTC density was gradually decreased. The expression of HIF-1α was gradually increased, and renal interstitial area was gradually expanded. PTC density was negatively correlated with the expression of TSP-1 and HIF-1α (r=-0.874 and r=-0.930, respectively). VEGF expression was positively correlated with PTC density (r=0.745). PTC density was negatively correlated with the area of renal fibrosis (r=-0.787). HIF-1α expression was positively correlated with the area of renal fibrosis (r=0.835, P<0.05). CONCLUSION: In mouse UUO model, the expression of TSP-1 is increased. The expression of VEGF is reduced. The peritubular capillary injury and tissue hypoxia are aggravated, and renal interstitial fibrosis area is expanded. Ischemia and hypoxia may play an important role in the progression of UUO.     

Effect of calcitonin gene-related peptide on myocardin expression and phenotypic switch in vascular smooth muscle cells

AIM: To investigate the effects of calcitonin gene-related peptide (CGRP) on myocardin expression and phenotypic switch in vascular smooth muscle cells (VSMCs). METHODS: VSMCs were obtained by aortic tissue adherent culture and treated with angiotensin Ⅱ (AngⅡ), AngⅡ + CGRP or AngⅡ + CGRP + CGRP_8-37. The protein expression of myocardin and the phenotypic proteins of the VSMCs was detected by Western blot. RESULTS: The expression of myocardin in cultured VSMCs showed downregulation along with time expansion. The protein level of myocardin was higher at 48 h and 72 h than that at baseline in the cultured VSMCs (P<0.05). However, the myocardin was lower at 48 h and 72 h than that at baseline after treatment with CGRP in cultured VSMCs (P<0.05). Furthermore, at 48 h in cultured VSMCs, the myocardin decreased along with α-smooth muscle actin (α-SMA) (P<0.05), and osteopontin (OPN) increased (P<0.05) in AngⅡ group compared with control group. After treatment with CGRP, the levels of myocardin and α-SMA become higher (P<0.05) but OPN was lower (P<0.05) in CGRP group than those in AngⅡ group. CGRP_8-37 abrogated CGRP-induced increase in myocardin and α-SMA and decrease in OPN in CGRP_8-37 group compared with CGRP group. CONCLUSION: CGRP may regulate the phenotypic switch of the VSMCs and maintain the cells in contractile phenotype through the upregulation of myocardin protein, which may be accomplished by the combination of CGRP and its receptor.     

Role of nucleolin in Ang II-induced phenotypic transformation of vascular smooth muscle cells

AIM: To investigate the effect of nucleolin on angiotensin II (Ang II)-induced phenotypic transformation of vascular smooth muscle cells (VSMCs). METHODS: Ang II was used to induce the phenotypic transformation of VSMCs. The spatial and temporal expression patterns of nucleolin, and the effects of Ang II on the expression of VSMC phenotypic transformation markers α-smooth muscle actin (α-SMA), calponin, smooth muscle protein 22 α (SM22α) and osteopontin (OPN) were investigated. The techniques of gene over-expression and RNA interference were used to assess the effect of nucleolin on the expression of Ang II-mediated VSMC phenotypic transformation markers. RESULTS: The expression of α-SMA, SM22α and calponin at the mRNA and protein levels was gradually decreased by Ang II stimulation, while the expression of OPN at mRNA and protein levels was gradually increased. The expression of nucleolin was gradually up-regulated in the VSMCs treated with Ang II at different concentrations for various duration (P<0.05). Ang II induced nucleolin translocation from the nucleus to cytoplasm. Over-expression of nucleolin promoted the VSMC phenotypic transformation induced by Ang II. Down-regulation of nucleolin suppressed the promotion of phenotypic transformation. CONCLUSION: Nucleolin promotes Ang II-induced phenotypic transformation of VSMCs, and its mechanism may be related to its function of cytoplasmic translocation.     

Activation of macrophage peroxisome proliferator-activated receptor α inhibits macrophage inflammation-induced cardiac fibroblast activation and migration

AIM: To investigate the effect of macrophage peroxisome proliferator-activated receptor α (PPARα) activation on macrophage inflammation-induced activation and migration of cardiac fibroblasts. METHODS: Mouse bone marrow-derived macrophages were treated with vehicle, PPARα agonist WY14643 (10 μmol/L), angiotensin Ⅱ (Ang II; 1 μmol/L) or Ang II+WY14643 for 24 h, and the supernatants were collected as conditioned medium (CM) to stimulate cardiac fibroblasts for additional 24 h. The mRNA levels of PPARα, interleukin-6 (IL-6), IL-1β and tumor necrosis factor-α (TNF-α) in the macrophages as well as fibrotic markers collagen type Ⅰ alpha 2 chain (Col1a2), collagen alpha 1 chain (Col3a1) and actin alpha 2 (Acta2) in the cardiac fibroblasts were detected by RT-qPCR. The protein levels of IL-6 and IL-1β in the macrophages as well as collagen I, collagen III and α-smooth muscle actin (α-SMA; encoded by Acta2 gene) in the cardiac fibroblasts were determined by Western blot. Wound-healing assay was applied to eva-luate the migration ability of cardiac fibroblasts. RESULTS: Ang II significantly increased the mRNA levels of pro-inflammatory factors, such as IL-6, IL-1α and TNF-α, but decreased the mRNA level of PPARα in the macrophages. Administration of PPARα agonist WY14643 dramatically decreased Ang II-induced mRNA levels of IL-6, IL-1β and TNF-α in the macrophages, and significantly decreased Ang II-induced protein expression of IL-6 and pro-IL-1β in the macrophages. The CM from Ang II-treated macrophages significantly up-regulated the mRNA levels of Col1a2, Col3a1 and Acta2 in the cardiac fibroblasts, which were inhibited by the CM from WY14643-treated macrophages. The same results were observed in the protein levels of collagen I, collagen III and α-SMA in the cardiac fibroblasts. Moreover, the CM from Ang II-treated macrophages significantly promoted cardiac fibroblast migration, whereas the CM from WY14643-treated macrophages markedly inhibited macrophage inflammation-induced cardiac fibroblast migration. CONCLUSION: WY14643-activated PPARα inhibits activation and migration of cardiac fibroblasts by attenuating Ang II-induced macrophage inflammatory response.     

Ginsenoside Rh1 attenuates unilateral ureteral obstruction-induced renal interstitial fibrosis in rats

AIM:To observe the effects of ginsenoside Rh1 (G-Rh1) on unilateral ureteral obstruction (UUO)-induced renal interstitial fibrosis and to investigate the underlying mechanisms. METHODS:Male Sprague-Dawley (SD) rats (n=40) were divided into the following 4 groups:UUO-operated group (UUO group), sham-operated group (sham group), UUO-operated plus a low dose (50 mg·kg^-1·d^-1) of G-Rh1 treatment (low G-Rh1 group) and UUO-operated plus a high dose (100 mg·kg^-1·d^-1) of G-Rh1 treatment group (high G-Rh1 group). The G-Rh1 treatment was carried out by gastric gavage from the next day after the UUO operation once a day for 2 weeks (14 d). Immediately after the final dose of G-Rh1, 24 h urine was collected for the urine protein test, and then the rats were euthanized. The blood was collected for the blood urea nitrogen (BUN) and serum creatinine (SCr) assays, and the kidney was removed for pathological and biochemical evaluations. RESULTS:The levels of 24 h urine protein did not show any significant diffe-rence among the groups, while significantly increased levels of BUN and SCr in UUO group were observed (P<0.05), which was prevented by the treatment with G-Rh1 at both doses in a dose-dependent manner. Pathological evaluation showed the renal tissue damage was obvious in UUO group, which was improved by the treatment with G-Rh1 at both doses. Immunohistochemcial analysis exhibited that UUO increased renal interstitial transforming growth factor-β₁ (TGF-β₁) expression, which was also inhibited by the treatment with G-Rh1 at both doses(P<0.05). Significantly increased protein expression of renal interstitial collagen type I, α-smooth muscle actin (α-SMA) and connective tissue growth factor (CTGF) in UUO group was detected, which was suppressed by the treatment with G-Rh1 at both doses. CONCLUSION:G-Rh1 improves UUO-induced renal dysfunction and attenuates interstitial fibrosis, which is mediated via modulation of TGF-β₁-related pro-fibrogenic signaling pathway.     

Role of hypoxia stimulated expression of connective tissue growth factor in renal interstitial fibrosis

AIM: To study the expression of connective tissue growth factor (CTGF) induced by hypoxia, and the role and mechanism of hypoxia on promoting renal interstitial fibrosis. METHODS: Renal interstitial fibrosis was induced by unilateral ureteral obstruction (UUO) in rat animal model for 9 days as in vivo studies; marker of hypoxia-HIF-1α mRNA and protein, the expression of CTGF in the obstructed kidneys were assessed by RT-PCR, immunohistochemistry and Western blotting respectively. In vitro, normal rat kidney interstitial fibroblast cells (NRK-49F) were exposed to hypoxia (1%O2) for up to 6 hours, hypoxia was confirmed by detecting the expression of HIF-1α protein in cells, cellular level of CTGF mRNA and protein were assessed by RT-PCR and Western blotting respectively. RESULTS: Neither HIF-1α mRNA nor HIF-1α protein was expressed in the kidney from sham-operated group of rats. High level of HIF-1α mRNA were occurred, and strongly HIF-1α positive immunostaining were seen in the tubular and interstitial cells in kidney from UUO rats. Expression and location of CTGF protein were paralleled and relevant with the expression of HIF-1α protein in kidney of UUO rats. In cultured NRK-49F cell line, subjected to hypoxia even for 6 hours stimulated the expression of CTGF mRNA and protein. CONCLUSION: Our results indicated that hypoxia could stimulate the expression of CTGF mRNA and protein in kidney from UUO rats, which may in turn contribute to renal interstitial fibrosis.     

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.     

RTN1A induces renal tubular epithelial cells to secrete VEGF and IL-8 and promotes diabetic nephropathy renal fibrosis via ERK signaling pathway

AIM:To investigate the effects of reticulon 1A (RTN1A) on the secretion of vascular endothelial growth facter (VEGF) and interleukin-8 (IL-8) in renal tubular epithelial cells, and on the diabetic nephropathy (DN) renal fibrosis, and to explore the underlying mechanism. METHODS:The mouse model of DN was established, and the blood glucose, kidney index, urine microalbumin (UMA) and creatinine clearance (CCr) were measured. The protein levels of RTN1A, p-ERK, ERK, VEGF, IL-8 and renal fibrosis markers α-smooth muscle actin (α-SMA) and fibronectin (FN) were determined by Western blot. Human renal tubular epithelial cell line HK-2 was treated with high glucose, and the ERK signaling proteins, fibrosis markers and secretion of cytokines were detected by Western blot and ELISA. The cells were treated with high glucose combined with RTN1A silencing or ERK inhibitor PD98059 for 24 h, and the ERK signaling proteins, fibrosis markers and secretion of cytokines were also detected by Western blot and ELISA. RESULTS:The blood glucose, kidney index, UMA and CCr in the DN mice were significantly higher than those in control group (P<0.05), suggesting that DN model was successfully constructed. The protein levels of RTN1A and its downstream protein p-ERK, the cytokines VEGF and IL-8, and the fibrosis markers α-SMA and FN were significantly increased in the DN model mice (P<0.05). The protein levels of RTN1A, p-ERK, VEGF, IL-8, α-SMA and FN were also significantly increased in the HK-2 cells after treated with high glucose for 24 h, while these proteins were significantly decreased after silencing of RTN1A expression. CONCLUSION:RTN1A may be associated with the occurrence and development of DN. Silencing of RTN1A expression inhibits DN renal inflammation and fibrosis through ERK signaling. RTN1A may be an effective therapeutic target.     

Expression of BMP-7 and its receptors in rats with unilateral ureteral obstruction

AIM:To explore the expression changes of b one morphogenetic protein-7 (BMP-7) and its receptors (BMPR-Ⅱ,ALK-2,ALK-3,A LK-6) in the renal tubulo-interstitial lesions induced by unilateral ureteral ob struction (UUO).METHODS:Rats were divided into normal control,sham operation a nd UUO groups,and sacrificed at postoperative day 1,3,7 and 14.The mRNA leve ls of BMP-7,BMPR-Ⅱ,ALK-2,ALK-3 and ALK-6 were examined by RT-PCR.The protei n expression site and level of BMP-7 was detected by immunohistochemistry staini ng.RESULTS:Compared to sham operation group,the mRNA levels of BM P-7,BMPR-Ⅱ,ALK-2 and ALK-3 were significantly decreased,but the change of AL K-6 mRNA was not marked in UUO rats.The reduction of mRNA expression levels of BMP-7,BMPR-Ⅱ,ALK-2 and ALK-3 in the kidney tissue aggravated along with the d elayed post-operated days.The results of immunohistochemistry staining indicate d that BMP-7 mainly expressed in renal tubular and interstitial,rarely in glome ruli.In UUO rats,the protein expression of BMP-7 decreased in varying degrees according to the post-operated days.CONCLUSION:The loss of BMP-7 and its receptors (BMPR-Ⅱ,ALK-2,ALK-3) were observed in the early phase of fibrotic process and this may play a very important role in mediating the renal tubulointerstital fibrosis.     

Gefitinib inhibits epithelial-mesenchymal transition by up-regulating Foxo3a expression in mice with bleomycin-induced lung fibrosis

AIM：To identify the effect of gefitinib on the expression of forkhead box protein O3a (Foxo3a), α-smooth muscle actin (α-SMA) and related signal pathway molecules in the mice with bleomycin-induced lung fibrosis and to investigate the inhibition mechanism of gefitinib on lung epithelial-mesenchymal transition. METHODS：Thirty Kunming female mice were randomly divided into 3 groups:control group (received normal saline intratracheally), bleomycin group (received bleomycin intratracheally, 3 mg/kg), and bleomycin plus gefitinib group (received bleomycin intratracheally and gefitinib orally, 20 mg/kg). All the mice were sacrificed 14 d after the treatments. Pulmonary histological changes were evaluated by hematoxylin-eosin staining and Masson trichrome staining. The mRNA levels of Foxo3a and α-SMA in the lung tissues were detected by RT-PCR. Nuclear Foxo3a, α-SMA, and phosphorylation of EGFR, Akt and Foxo3a in the lung tissues were determined by Western blotting. RESULTS：Gefitinib inhibited bleomycin-induced lung fibrosis and significantly decreased the scores of lung inflammation and fibrosis. Foxo3a mRNA expression and total Foxo3a protein expression were increased, while the phosphorylated Foxo3a was decreased. Nuclear Foxo3a was increased significantly. Meanwhile, phosphorylated EGFR and Akt were decreased. The level of α-SMA was observably increased. CONCLUSION:Gefitinib restores Foxo3a activity and reduces α-SMA expression by modulating EGFR/Akt activity, thus inhibiting bleomycin-induced lung fibrosis.     

Role of miR-433 in fibrosis of NIH-3T3 cells and silica-induced pulmonary fibrosis in mice

AIM To study the role and regulatory mechanism of microRNA-433 (miR-433) in fibrosis. METHODS TargetScan was used to predict the potential target genes of miR-433. The changes of miR-433 expression were detected after transforming growth factor β1 (TGF-β1) treatment of mouse embryonic fibroblasts (NIH-3T3 cells) for 24 h. The effects of miR-433 mimic on the expression of p-SMAD2, fibronectin (FN), α-smooth muscle actin (α-SMA) and connective tissue growth factor (CTGF) in TGF-β1 treated cells were examined. The effects of miR-433 mimic transfection on the viability and S-phase fraction of NIH-3T3 cells induced by TGF-β1 were detected by CCK-8 assay and flow cytometry. A model of silica-induced pulmonary fibrosis in mice was established, and agomiR-433 was used for intervention. HE staining and Masson staining were used to observe the effect of miR-433 on pulmonary fibrosis in the mice. The expression of α-SMA in lung tissues was detected by immunohistochemistry. RESULTS miR-433 specifically bound to the 3'-UTR of SMAD2 and inhibited its expression at protein and mRNA levels. TGF-β1 down-regulated the expression of miR-433 in NIH-3T3 cells, up-regulated the protein level of p-SMAD2 and the expression of FN, α-SMA and CTGF at protein and mRNA levels, and increased the viability and the number of S-phase cells. miR-433 mimic reversed the effects of TGF-β1 on NIH-3T3 cell viability and S-phase arrest. In a model of silica-induced pulmonary fibrosis in mice, agomiR-433 inhibited the progress of pulmonary fibrosis and reduced the expression of α-SMA in mouse lung tissues. CONCLUSION miR-433 may interfere with TGF-β1/SMAD2 signaling pathway through targeting SMAD2, thus participating in the regulation of fibrosis process.