Effect of antifibrotic herb serum on rat hepatic stellate cell proliferation and collagen synthesis

AIM: To investigate the effect of Chinese herbs, Ganxianfang(GXF), on rat hepatic stellate cells (HSC) proliferation and collagen synthesis. METHODS: Two types of herb serum, portal venous serum and circumferential venous serum, were prepared from rats infused intragastrically with 16, 8, 4 times adult dose of GXF decoction. HSC isolated from rat liver were processed with the above sera in vitro. Then we mensurated the radioactivity of HSC admixed with [[³H]H]proline and [[³H]H]thymine to judge the effect on proliferation and collagen synthesis of HSC. RESULTS: Both two types of serum collected 0.5, 1, 2 h after intragastrical infusion inhibited HSC proliferation (P＜0.05), and the serum collected 1 h after intragastrical infusion had the strongest effect (P＜0.05). Portal serum decreasea collagen synthesis (P＜0.05), but circumferential serum had no effect (P＞0.05). CONCLUSION: Inhibition of HSC proliferation and decrease of collagen synthesis may contribute to the GXF antifibrotic action.     

Effects of c-myb antisense RNA on the proliferation and collagen Ⅰ gene expression in cultured hepatic stellate cells

AIM:To investigate the effects of c-myb antisense RNA on the proriferation and collagen Ⅰ gene expression in cultured hepatic stellate cells(HSC) in rats.METHODS:The c-myb antisense gene recombinant retroviral vector(pDOR-myb) was constructed, and then was transfected into retroviral package cell line PA 317 by means of N-[1-(2,3-Dioleoyloxy) propyl]-N, N, N-trimethylammonium methyl-sulfate(DOTAP) liposomal transfection reagent. The pseudoviruses produced from the resistant PA317 cells selected with G418 were collected, with which HSCs isolated from rat liver were infected. The cell proliferation was measured by MTT method, c-myb, α₁-Ⅰ collagen mRNA expression and c-myb protein in HSCs were detected with semi-quantitative RT-PCR and western-blot, respectively.RESULTS:HSCs from rats were isolated successfully with the viability >98%. In the pDOR-myb infected HSCs, c-myb expression levels, the cell proliferation, and α₁-Ⅰ collagen mRNA expression were repressed significantly.CONCLUSIONS:c-myb plays a key role in the activation and proliferation of HSC. c-myb antisense RNA can inhibit cell proliferation and α₁-Ⅰ collagen mRNA expression in the infected HSC. These data suggest that inhibition of c-myb gene expression would be a potential way for the treatment of liver fibrosis.     

Inhibitory effect of sorafenib on collagen synthesis in human hepatic stellate cells

AIM: To investigate the effects of sorafenib on collagen synthesis in human hepatic stellate cells (HSCs). METHODS: HSC cell line LX-2 was used in vitro in this study. -proline incorporation assay was performed to measure the collagen synthesis. Immunocytochemistry was applied to detect type I collagen and real-time PCR was used to determine the mRNA expression of collagen α1 (I). RESULTS: Stimulation with platelet-derived growth factor (PDGF) induced the increase in type I collagen synthesis, while treatment with sorafenib (10.0 μmol/L) for 24 h markedly decreased the collagen synthesis. Sorafenib resulted in dose-dependent and time-dependent decrease in collagen synthesis in LX-2 cells in the absence or presence of PDGF by -proline incorporation assay. The inhibition rates were 22.69%, 37.52% and 71.74%, respectively, when LX-2 cells was treated with sorafenib at 10.0 μmol/L for 12 h, 24 h and 48 h. Sorafenib dose-dependently blocked the mRNA expression of collagen α1 (I) in LX-2 cells stimulated with PDGF. Sorafenib at the concentrations of 2.5 μmol/L, 5.0 μmol/L and 10.0 μmol/L down-regulated the mRNA expression of collagen α1 (I) in LX-2 cells by 58.66%, 67.06% and 81.64%, respectively. CONCLUSION: Sorafenib inhibits the collagen synthesis and blocks the expression of type I collagen at mRNA and protein levels in vitro in LX-2 cells. Therefore, sorafenib may be a potential therapeutic agent in the treatment of liver fibrosis.     

Role of endogenous angiotensin II in the pathogenesis of aortic calcification in rats

AIM: To explore the effects of angiotensin II on aortic calcification in the rat. METHODS: Arterial calcification of Sprague-Dawley rats was induced by vitamin D₃ plus nicotine. Calcification was confirmed by Von Kossa staining, measurement of calcium content, [⁴⁵Ca²⁺]accumulation and alkaline phosphatase (ALP) activity of vascular tissue. RESULTS: The results showed that calcium content, [⁴⁵Ca²⁺]accumulation and ALP activity in calcified arteries increased significantly compared with those of control. Ang Ⅱ levels in plasma and aortic tissues and the amount of angiotensinogen mRNA in calcified aorta were also increased as compared with control. Captopril (inhibitor of ACE) and losartan (Ang Ⅱ receptor inhibitor) decreased significantly the content of calcium, [⁴⁵Ca²⁺] uptake and ALP activity in calcified aorta. Ang Ⅱ levels in plasma and aortic tissues and the amount of angiotensinogen mRNA in aortic tissue were down-regulated by captopril. The amount of angiotensinogen mRNA and the content of Ang Ⅱ in the calcified aorta were also decreased by losartan. CONCLUSION: The captopril and losartan significantly alleviate the vascular calcification.     

Role of angiotensin II and angiotensin II receptors in vascular smooth muscle cells migration

AIM:To determine the effects of Angiotensin II(AngII) on migration of rat smooth muscle cells and to investigate the mechanisms underlying Ang II action in the development of injured vascular disease. METHODS:VSMCs isolated from aortic media of Wistar rats and cultured by the modified explant method were adopted. In prersence and absence of AngII, the expression of AngII receptor and reorganization of the actin cytoskeleton of VSMCs were studied by immunocytochemistry technique, fluorocytochemistry technique. The migration assays were performed by a modified Boyden's chamber. And the effects of AT₁R antagonist (CV-11974), AT₂R antagonist (PD123319) on aforementioned target were studied.RESULTS:VSMCs migration was stimulated by addition of AngII. The dynamic reorganization of actin cytoskeleton may be an important mechanism by which AngII facilitates VSMC motility. The expression of AT₁R in VSMCs can be upregulated after treatment with AngII initially, then decreased gradually. The expression of AT₁R was downregulated by AT₁R antagonist. The effect of AngII on VSMCs migration was mediated by AT₁R, while AT₂R had no significant effect.CONCLUSION:The dynamic reorganization of actin cytoskeleton is required for AngII-induced VSMC migration, and this effect is mediated by AT₁R .     

Inhibitory effects of FRNK on collagen synthesis in hepatic stellate cells

AIM:To investigate the effect of focal adhesion kinase-related non-kinase (FRNK) on collagen synthesis in hepatic stellate cells (HSCs).METHODS:HSCs were transfected with FRNK by cationic liposome method. The expressions of FRNK at the protein level in HSCs were detected by Western blotting analysis. HSCs collagen synthesis capability was examined by［3H］-Pro incorporation assay.RESULTS:The exposure of HSCs to FRNK led to the up-regulated expression of FRNK protein, and it was at 48 h after transfection that the FRNK protein content was the highest. Moreover, after FRNK was transfected successfully in HSCs, the total collagen synthesis and type I collagen synthesis were inhibited.CONCLUSION:After FRNK is transfected successfully in HSCs using Lipofectamine, the synthesis of total and type I collagen in HSCs is inhibited.     

Effects of angiotensin II receptor antagonist on remodeling of renal arterioles in hypertension

AIM: To investigate the effects of angiotensin II receptor antagonist on remodeling of renal arterioles in hypertension. METHODS: Eighteen 4 weeks old male rats were divided into three groups: Wistar-Kyoto rats (WKY) for normotensive group, and spontaneously hypertensive rats (SHR) for hypertensive group, and SHR treated with losartan orally (15 mg·kg^-1·d^-1). The rats were raised to 16 weeks old. The morphometric parameters of the renal arterioles, and the widths of vascular smooth muscle cells (VSMC) and intercellular space were studied on kidney slices by light microscope and electromicroscope respectively, combined with computer-assistant image analysis system. The minimal renal vascular resistance (RVR_min) was studied by isolated kidney perfusion system. RESULTS: The systolic blood pressure of the tail artery, wall thickness, wall area, ratio of wall thickness to inner diameter, width of VSMC of renal arterioles and RVR_min were all smaller or lower in losartan group than those of SHR.     

Roles of Rho-kinase in rat cardiac fibroblasts proliferation and collagen synthesis induced by angiotensin Ⅱ

AIM: To investigate the role of Rho-kinase signal pathway in rat cardiac fibroblasts (CFBs) proliferation and collagen synthesis induced by angiotensinⅡ (AngⅡ). METHODS: CFBs of neonatal Sprague-Dawley (SD) rats were isolated with the method of trypsin digestion and differential anchoring velocity. The CFBs were stimulated with AngⅡto induce fibrosis. Proliferation of CFBs was observed by MTT coloricmetric assay. Synthesis of collagen was detected by the hydroxyproline. The expression of Rho-kinase mRNA was examined using RT-PCR analysis. The extent of phosphorylation of myosin-binding subunit (MBS-P) of myosin phosphatase was quantified by Western blotting analysis, which was used to evaluate the activity of Rho-kinase.RESULTS: (1) Stimulation of neonatal SD rat CFBs with AngⅡ (10-7 mol/L) significantly increased CFBs proliferation and collagen synthesis (P<0.01). (2）Stimulation of neonatal SD rat CFBs with AngⅡ (10-7 mol/L) significantly increased the expression of Rho-kinase mRNA and rapidly activated Rho-kinase in a time-dependent manner. (3) Within a concentration coverage, hydroxyfasudil (H4413), a Rho-kinase inhibitor, effectively inhibited AngⅡ-induced CFBs proliferation and collagen synthesis (P<0.05 or P<0.01).CONCLUSION: Rho-kinase signal pathway may be one of the most important signal transducter for AngⅡ-induced CFBs proliferation and collagen synthesis in neonatal SD rats.     

Effects of Nrf2 overexpression on proliferation,activation and collagen type I synthesis in cultured hepatic stellate cells stimulated by ethanol

AIM：To investigate the effects of nuclear factor E2-related factor 2 (Nrf2) overexpression on the proliferation, cell cycle distribution, collagen type I (Col I) synthesis and alpha-smooth muscle actin (α-SMA) expression in cultured hepatic stellate cell line HSC-T6 stimulated by ethanol. METHODS：Cultured HSC-T6 cells were transfected with pEGFP-Nrf2 or pEGFP-N1 (empty vector) plasmid by liposome transient transfection. The cells were divided into control group, ethanol group, ethanol+pEGFP-Nrf2 group and ethanol+pEGFP-N1 group. The mRNA expression of Nrf2, α-SMA and Col I was determined by RT-PCR, and their protein expression was detected by Western blotting. Cell proliferation was assessed by MTT assay, and cell cycle was detected by flow cytometry. RESULTS：The pEGFP-Nrf2 plasmid was successfully transfected into HSC-T6 cells, and the mRNA and protein expression of Nrf2 was higher than other three groups 48 h after transfection (P<0.05). Compared with control group, the cell proliferation and the mRNA and protein expression of α-SMA and Col I in ethanol group and ethanol+pEGFP-N1 group were significantly increased (P<0.05), and the numbers of HSC-T6 cells were decreased in G1 phase and increased in S phase (P<0.05), without significant differences between the two groups (P>0.05). Meanwhile, the cells in ethanol+pEGFP-Nrf2 group showed significantly decreased proliferation level, down-regulated mRNA and protein expression of α-SMA and Col I, higher numbers in G1 phase and lower numbers in S phase compared with ethanol group and ethanol+pEGFP-N1 group (P<0.05). CONCLUSION：Nrf2 overexpression could significantly down-regulate the expression of α-SMA and Col I and cause G1/S phase arrest in HSC-T6 cells cultured with ethanol, thus inhibiting the proliferation and activation of the cells.     

Effect of siRNA-mediated Smad3 silence on proliferation and apoptosis in activated hepatic stellate cells

AIM: To investigate the effects of siRNA-mediated Smad3 silence on proliferation and apoptosis in activated hepatic stellate cells (HSCs).METHODS: HSCs-T6 cells were divided into 3 groups: blank group, negative control group and siRNA-Smad3 transfection group. The siRNA-Smad3 was transfected into HSCs-T6 cells. At different time points after transfection, cell proliferation was measured by CCK-8, cell apoptosis was detected by flow cytometry, and protein levels of P53 and Bcl-2 were determined by immunocytochemistry.RESULTS: HSCs proliferation was significantly inhibited at the time points of 24 h, 48 h and 72 h after transfection. Meanwhile, the apoptosis of HSCs was significantly increased in siRNA-Smad3 transfection group (P<0.01). Compared to the control cells, the protein expression of P53 was significantly increased while Bcl-2 protein was significantly decreased 48 h after transfection in siRNA-Smad3 transfection group (P<0.01).CONCLUSION: The siRNA-mediated Smad3 silence significantly inhibits HSCs proliferation and induces apoptosis by up-regulating the P53 expression and down-regulating the Bcl-2 expression in HSCs.     

Levels of histone modifications in activated primarily cultured rat hepatic stellate cells

AIM: To investigate the changes of histone modifications during the activation of primarily cultured rat hepatic stellate cells (HSCs) and the relationship between histone modification patterns and α-smooth muscle actin (α-SMA) expression, and to explore the roles of histone modifications in the activation of HSCs. METHODS: The rat HSCs were isolated by in situ perfusion of collagenase combined with density gradient centrifugation, cultured in vitro and identified by immunofluorescence staining. The morphological features of the cells were observed under inverted microscope. The changes of desmin and α-SMA during the activation of HSCs were detected by immunofluorescence staining and Western blotting. The levels of histone 3 lysine 4 dimethylation (H3K4me2), histone 3 lysine 9 dimethylation (H3K9me2), histone 3 lysine 9 acetylation (acH3K9) and histone 4 lysine 12 acetylation (acH4K12) in quiescent HSCs and activated HSCs were determined by Western blotting.RESULTS: The morphology of HSCs shifted from a quiescent phenotype to highly activated myofibroblast during the culture. Immunofluorescence staining and Western blotting showed that the expression levels of α-SMA and desmin were increased over time and reached maximum at 15 d. According to the results of cell morphology and immunofluorescence staining, the cells cultured for 24 h and 15 d were quiescent and activated HSCs, respectively. Compared with quiescent HSCs, there were higher H3K4me2 and lower H3K9me2, acH3K9 and acH4K12 modification levels in activated HSCs (P<0.01). CONCLUSION: Histone modifications show anomalous expression during the activation of primarily cultured rat HSCs. Histone modifications may contribute to the transdifferentiation of HSCs and the development of hepatic fibrosis.     

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.     

Effects of angiotensin Ⅱ on ATP binding cassette transporter A1 in THP-1 derived foam cells

AIM:To study the influence of angiotensin Ⅱ (AngⅡ) on ATP-binding cassette transporter A1 in THP-1 derived foam cells. The variance of the expression of ABCA1, the content and the effluent rate of cholesterol were also investigated. METHODS:The regulatory effect of AngⅡ on the expression of ABCA1 mRNA and protein in THP-1 derived form cells were measured by RT-PCR and Western blotting. The effect of variance of cholesterol content was measured by zymochemistry via-fluorospectrophotometer, cholesterol effluent was measured by liquid scintillator. RESULTS:A positive facilitative effect of Ang Ⅱon form cells was observed. Total cholesterol content were increased significantly by Ang Ⅱ treatment (P<0.05). The mRNA and protein of ABCA1 were down-regulated significantly by Ang Ⅱ stimulation (P<0.05). Irbesartan reduced the total cholesterol content significantly (P<0.05). Meanwhile, the increase in the effluent rate of cholesterol and the expression of ABCA1 were observed (P<0.05). CONCLUSION:The effects of Ang Ⅱ on the formation of foam cells and atherosclerosis may be correlated to the activation of AT1 receptor and down-regulation of ABCA1.     

Effects of MT1-MMP on collagen metabolism regulated by FRNK in hepatic stellate cells

AIM: To investigate the effect of FAK-related non-kinase (FRNK) on the expression of membrane-type matrix metalloproteinase-1 (MT1-MMP) in hepatic stellate cells (HSC). METHODS: FRNK were transfected into HSCs by cationic liposome method. The protein levels of FRNK in HSC were assayed by Western blotting. The levels of MT1-MMP were determined by RT-PCR for mRNA and by Western blotting for protein, respectively. RESULTS: The up-regulated expression of FRNK protein was observed and it was at 48 h after transfection that the FRNK protein content was the highest (P<0.05). The expressions of MT1-MMP mRNA and protein were also up-regulated by the transfection of FRNK, and it was at 48 h after transfection that the MT1-MMP protein content was significantly increased. CONCLUSION: The mRNA and protein of FRNK were over-expressed in HSC transfected with the gene of FRNK. The inhibitory effect of FRNK on the collagen synthesis in HSC may be through the up-regulation of MT1-MMP.     

Antagonistic effect of angiotensin II type 1 receptor blocker candesartan on angiotensin II-induced proliferation of primary acute myeloid leukemia cells

AIM: To explore the antagonistic effect and mechanism of candesartan on angiotensin II (Ang II)-induced proliferation of primary acute myeloid leukemia (AML)cells. METHODS: MTT assay was used to observe the proliferation effect of Ang II on primary AML cells and normal bone marrow mononuclear cells, and the antagonistic effects of candesartan and PD123319 (an antagonist of AT2R) were also observed. Akt phosphorylation was detected by Western blotting when the cells were treated with candesartan and a PI3K inhibitor LY294002.RESULTS: Compared with the control cells, Ang II significantly increased the proliferation of AML cells in a dose-and time-dependent manner (P<0.05). Ang II did not stimulate the proliferation of normal bone marrow mononuclear cells. The proliferative effect of Ang II was effectively blocked by the AT1R blocker candesartan (P<0.05). PI3K inhibitor strongly repressed the Ang II-induced cell proliferation (P<0.05). Candesartan significantly reduced Akt phosphorylation promoted by Ang II on primary AML cells (P<0.05).CONCLUSION: Candesartan effectively inhibits Ang II-induced proliferation of primary AML cells by down-regulating PI3K/Akt signaling pathway, indicating a new possible treatment mechanism in some AML cells.     

Effects of angiotensin II type 2 receptor blocker on wound healing in a mouse skin full-thickness injury model

AIM：To observe the effect of angiotensin II (Ang II) and its type 2 receptor (AT2R) on re-epithelialization, granulation tissue formation and growth factor production during wound healing, and to explore the possible mechanism by which Ang II and AT2R influence wound healing. METHODS：Two full-thickness skin wounds were created on the dorsum of C57BL/6J mice. The animals were treated with or without AT2R blocker PD123319 at a dose of 10 mg/kg daily after wounding. Specimens were taken from the wound of each mouse on days 3, 5, 7, 9, 11, 13 and 15 after wounding. Re-epithelialization and granulation tissue formation in the wounded skin tissues were evaluated by HE staining. The production of growth factors,epidermal growth factor (EGF),vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF) in wounded tissues during the healing process was detected by ELISA. RESULTS：Treatment with PD123319 significantly increased the rate of re-epithelialization and the area of granulation tissue compared with control group at 5 d and 7 d after wounding. Moreover, peritoneal application of PD123319 increased the production of EGF, VEGF and bFGF in the wounded tissues at the indicated time points after wounding. CONCLUSION：AT2R blocker PD123319 accelerates wound healing via promoting re-epithelialization,granulation tissue formation and growth factor production.     

Effects of puerarin on apelin-12, angiotensin II,NO and blood pressure in renovascular hypertensive rat

AIM: To investigate the effects of puerarin on blood pressure in renovascular hypertensive rats, and to measure puerarin-induced changes of apelin-12, angiotensin II (Ang II) and nitric oxide(NO), the factors related to development of hypertension. METHODS: Sixty-five male Sprague-Dawley rats were used, of which 8 rats were randomly selected as sham operation group, and the remaining were used to make two-kidney, one-clip model. The rats that met the criterion for Goldblatt hypertensive rat model were randomly allocated into 5 groups: high-, middle- and low-dose puerarin groups, captopril group, and model group. The drugs were administered for 6 weeks. Blood pressure was measured every 2 weeks. Six weeks after treatment, all rats were sacrificed under deep anesthesia. Blood and kidney samples were collected. The level of apelin-12 in serum and kidneys was detected by ELISA. The level of Ang II in plasma and kidneys was measured by radioimmunoassay. NO level in serum was examined by nitrate reductase assay. RESULTS: Puerarin had an antihypertensive effect in a dose-dependent manner. Marked decreases in the level of serum apelin-12 in high- and middle-dose puerarin groups were observed(P<0.01). Puerarin at low dose did not cause obvious change in the content of apelin but still reached significant level (P<0.05). As the dose of puerarin went up, the level of apelin-12 in the kidneys was gradually decreased. Puerarin at high and middle doses obviously reduced the level of AngII in plasma, while purarin at low dose did not produce any significant effects. Puerarin at high and middle doses markedly increased the level of NO in serum, but puerarin at low dose did not induce any significant changes. CONCLUSION: Puerarin has an antihypertensive effect, and its mechanism may be related to inducing the changes of apelin, Ang II and NO, and regulating the balance among those factors.