Effects of interferon-alpha on expression of hepatic stellate cell and transforming growth factor-β1 and α-smooth muscle actin in rats with hepatic fibrosis

AIM: To investigate the effect of interferon-α(IFN-α) on preventing or reversing hepatic fibrosis in rat experimental model induced by CCl4.METHODS: One hundred and ten Sprague-Dawley rats were divided into five groups: group A (normal controls,n=18), group B (fibrotic model controls, n=22), group C (IFN-α prevention, n=22) initially treated with intra-muscular injection of IFN-α in saline daily at the doses of 1×105U for 6wk, group D (IFN-α treatment, n=24) treated with intra-muscular injection of IFN-α in saline daily at the doses of 1×105U for 6wk after the first 6wk, group E (0.9% sodium chloride treatment control, n=24) treated with intra-muscular injection of 0.01mL/kg daily for 6wk after the first 6wk. At the end of the experiment, all rats of each group were killed. Samples of the liver obtained by biopsy were subjected to histological, immunohistochemical and electron microscopic studies for the expressions of transforming growth factor-β1(TGF-β1) and α-smooth muscle actin (α-SMA).RESULTS: The expressions of TGF-β1, the number of activated hepatic stellate cells and α-SMA in hepatic tissue of group C were significantly less than those of group B(P<0.01). The degree of fibrosis score in group B was also significantly less than that of group C under light microscope (P<0.01).CONCLUSION: IFN-α can inhibit the production of TGF-β1, decrease HSC activation and stimulate its apoptosis.     

Expression of alpha-smooth muscle actin in murine bone marrow stromal cells

Human fibrotic bone marrow (BM) stroma has been shown to contain alpha-smooth muscle actin (alpha-SMA)-positive cells. These closely resemble myofibroblasts that were described in other fibrotic tissues. We studied the expression of alpha-SMA in a series of murine BM-derived stromal cell lines to investigate the cellular origin and functional significance of myofibroblast-like cells in hematopoietic tissues. Although these cell lines differed in their biologic properties, most of them expressed alpha-SMA under certain conditions. Cells expressing alpha-SMA constituted a minor population in post-confluent, growth-arrested cultures. However, the incidence of cells expressing alpha-SMA increased significantly when cultures were transferred to nonconfluent conditions. A similar increase in alpha-SMA-positive cells occurred after a strip of cells was scraped away from the confluent cell layer; the cells of the affected area acquired alpha-SMA-positive contractile phenotype. The relationship between alpha-SMA expression and hematopoietic activity was studied using a cloned cell line of BM origin (14F1.1). The ability of these endothelial-adipocyte cells to support hematopoiesis in vitro was maximal under confluent conditions, whereas their expression of alpha-SMA under such conditions was residual. Moreover, in long-term BM cultures supported by confluent 14F1.1 cells, stromal areas associated with proliferating hematopoietic precursors, known as "cobblestone areas," were devoid of alpha-SMA-positive cells. These observations suggest that the expression of alpha-SMA is reversible and inversely related to hematopoietic activity.     

Enhanced expression of transforming growth factor-beta 1 in inflammatory cells, alpha-smooth muscle actin in stellate cells, and collagen accumulation in experimental granulomatous hepatitis caused by Toxocara canis in mice

Although toxocaral granulomatous hepatitis (TGH) characterized with a dominant-Th2 type immune response is a self-limiting disease, little is known concerning the role of fibrosis-related cytokine transforming growth factor-beta 1 (TGF-beta 1) in pathogenesis of TGH. A detailed histological and quantitatively immunohistochemical analysis of TGF-beta 1, alpha-smooth muscle actins (alpha-SMA), and collagen was performed on the liver tissues from mice infected with Toxocara canis as assessed between day 1 and 42 weeks post-infection (DPI or WPI). TGF-beta1 was detected mainly in infiltrating leukocytes in lesions with strong expressions from 4 to 16 WPI. Larvae per se also exhibited strong TGF-beta 1-like molecule expressions in the trial. Alpha-SMA was detected predominantly in hepatic stellate cells (HSC) which surrounded the lesions with moderate expressions largely throughout the period of the entire experiment. Collagen was observed to accumulate in inflammatory lesions and biliary basement with moderate to strong expressions from 1 WPI onwards in the trial. Since many evidences have indicated that leukocytes have the potential to influence HSC by producing TGF-beta 1 which can affect HSC to increase collagen synthesis in various liver diseases, we may propose that persistently elevated TGF-beta 1 expression in infiltrating leukocytes and active HSC with marked alpha-SMA expressions may contribute to healing of injured sites through up-stimulation of collagen deposition; in contrast, abnormally persistent collagen accumulation may cause irreversible fibrotic injury in the TGH.     

CHB患者不同分级、分期肝组织中TGF-β1的表达研究

目的 观察慢性乙型病毒性肝炎(CHB)患者,不同G、S分级、分期的肝穿刺组织中,细胞转化生长因子β1(TGF-β1)的表达,及与Knodell评分系统的相关性。方法 采用免疫组化技术,观察107例不同程度CHB患者肝穿刺组织中TGF-β1的蛋白表达定位,并行半定量评分,半定量结果分别与现行病理诊断标准慢性肝炎分级、分期及Knodell评分系统进行统计学分析。结果 随着患者病变程度的加重,肝组织中TGF-β1的表达定位,由肝小叶内窦周隙表达为主趋向于汇管区和纤维隔表达为主;且这种肝组织内阳性表达量与Knodell评分呈显著正相关。结论TGF-β1是肝纤维化发生的重要致病因子之一,炎症可诱发TGF-β1的表达。     

Role of transforming growth factor-beta signaling pathway in pathogenesis in pathogenesis of benign biliary stricture

AIM:To characterize the expression of members of the transforming growth factor-beta(TGF-β)/Smad/connective tissue growth factor(CTGF)signaling pathway in the tissue of benign biliary stricture,and to investigate the effect of TGF-β signaling pathway in the pathogenesis of benign biliary stricture.METHODS:Paraffin embedded materials from 23 cases of benign biliary stricture were analyzed for members of the TGF-β/Smad/CTGF signaling pathway.TGF-β1,TβRⅠ,T13RⅡ,Smad4,Smad7 and CTGF protein were detected by immunohistochemical strepto-advidinbiotin complex method,and CTGF mRNA was evaluated by hybridization in situ,while 6 cases of normal bile duct served as controls.The percentages of positive cells were counted.The correlation between TGF-β1,Smad4 and CTGF was analyzed.RESULTS:The positive expression ratios of TGF-β1,TβRⅠ,T13RⅡ,Smad4,CTGF and CTGF mRNA in 23 cases with benign biliary stricture were 91.3%,82.6%,87.0%,78.3%,82.6% and 65.2%,respectively,significantly higher than that in 6 cases of normal bile duct respectively(vs 33.3%,16.7%,50.0%,33.3%,50.0%,16.7%,respectively,P＜0.05).The positive expression ratio of Smad7 in cases with benign biliary stricture was 70.0%,higher than that in normal bile duct,but this difierence is not statistically significant 70.0% vs 50%,P＞0.05).There was a positive correlation between positive expression of TGF-β1,Smad4 and CTGF in cases with benign biliary stricture.CONCLUSION:The high expression of TGF-β/Smad/CTGF signaling pathway plays an important role in the pathogenesis of benign biliary stricture.     

Expression of transforming growth factor-beta 1 in hepatocellular carcinoma in comparison with the non-tumor tissue

BACKGROUND/AIMS: TGF-beta 1 (transforming growth factor-beta 1) has been shown to be overexpressed in various cancer cells including hepatocellular carcinoma cells. In this study, we examined the association of the immunohistochemical expression of TGF-beta 1 in hepatocellular carcinoma tissues with the clinicopathological findings. METHODOLOGY: Thirty liver tumor biopsy specimens obtained with ultrasound guidance and in which tumor-tissue and non-tumor tissue existed were examined. TGF-beta 1 was stained using rabbit anti-human TGF-beta 1 antibody. RESULTS: TGF-beta 1 was expressed mainly in the cytoplasm and plasma membrane of the hepatocellular carcinoma cells, while it was stained in the fibrous septa and sinusoidal cells in the non-tumor tissue. When comparing the intensity of TGF-beta 1 staining in the hepatocellular carcinoma tissue with that in the non-tumor tissue, the former was more intense than the latter in 21 (70%) of the 30 cases. Although the expression of TGF-beta 1 in the hepatocellular carcinoma tissue was not related to the tumor size of hepatocellular carcinoma, it was correlated with the histological differentiation: the lower the histological differentiation grade of hepatocellular carcinoma was, the more intense was the TGF-beta 1 staining in hepatocellular carcinoma tissue. In addition, TGF-beta 1 tended to be overexpressed in the trabecular type of hepatocellular carcinoma. To elucidate the relationship of TGF-beta 1 staining with apoptosis in hepatocellular carcinoma cells, we performed terminal deoxynucleotidyl transferase-mediated DUTP biotinnick end labeling (TUNEL) in 11 of the 30 specimens. No positive cells for TUNEL were detected in the hepatocellular carcinoma tissues. CONCLUSIONS: These results indicated that the expression of TGF-beta 1 was associated with the histological differentiation of hepatocellular carcinoma cells.     

Autoimmune manifestations in the transforming growth factor-beta 1 knockout mouse

Targeted disruption of the transforming growth factor-beta 1 (TGF-beta 1) gene in mice results in the development of a massive multifocal inflammatory disease in many tissues. Because no detectable pathogen was identified, we examined whether autoimmune mechanisms played a role in initiating or maintaining the inflammatory disease. The serum of TGF- beta 1 knockout mice contained elevated titers of antibodies to nuclear antigens (ssDNA, dsDNA, Sm, and RNP) as well as reactivity against the 16/6 idiotype (16/6 Id). In addition, Ig deposits were detected in renal glomeruli of TGF- beta 1 knockout mice. Transplantation of TGF- beta 1 knockout hematopoietic cells into normal irradiated recipients resulted in a similar profile of autoantibody production as well as in the induction of inflammatory lesions. Our results describe autoimmune activity that ensues when the TGF-beta 1 cytokine is absent.     

Role of transforming growth factor-beta signaling pathway in pathogenesis of benign biliary stricture

AIM： To characterize the expression of members of the transforming growth factor-beta （TGF-β）/Smad/ connective tissue growth factor （CTGF） signaling pathway in the tissue of benign biliary stricture, and to investigate the effect of TGF-β signaling pathway in the pathogenesis of benign biliary stricture. METHODS： Paraffin embedded materials from 23 cases of benign biliary stricture were analyzed for members of the TGF-β/Smad/CTGF signaling pathway. TGF-β1, TβRⅠ, TβRⅡ, Smad4, Smad7 and CTGF protein were detected by immunohistochemical strepto-advidinbiotin complex method, and CTGF mRNA was evaluated by hybridization in situ, while 6 cases of normal bile duct served as controls. The percentages of positive cells were counted. The correlation between TGF-β1, Smad4 and CTGF was analyzed. RESULTS： The positive expression ratios of TGF-β1, TβR Ⅰ , TβR Ⅱ, Smad4, CTGF and CTGF mRNA in 23 cases with benign biliary stricture were 91.3%, 82.6%, 87.0%, 78.3%, 82.6% and 65.2%, respectively, significantly higher than that in 6 cases of normal bile duct respectively （vs 33.3%, 16.7%, 50.0%, 33.3%, 50.0%, 16.7%, respectively, P 〈 0.05）. The positive expression ratio of Smad7 in cases with benign biliary stricture was 70.0%, higher than that in normal bile duct, but this difference is not statistically significant 70.0% vs 50%, P 〉 0.05）. There was a positive correlation between positive expression of TGF-β1, Smad4 and CTGF in cases with benign biliary stricture. CONCLUSION： The high expression of TGF-β/Smad/ CTGF signaling pathway plays an important role in the pathogenesis of benign biliary stricture.     

Expression of vascular endothelial growth factor and transforming growth factor-beta 1 on the neointimal of balloon-injured rabbit carotid arteries

Objective To make an rabbit models of restenosis and observed the expression of VEGFmRNA and TGE-β1 mRNA on the intireal proliferation in the mode. We also explored the relationship between VEGFmRNA, TGF-β1 mRNA and restenosis.     

Activation of transforming growth factor-beta1 in diabetic kidney disease

Recent data have suggested that certain growth factors and cytokines are involved in the development of diabetic nephropathy. The aim of this study was to investigate whether circulating transforming growth factor beta 1 (TGF-beta1) and tumor necrosis factor alpha (TNF-alpha) are associated with diabetic kidney disease. Serum levels of active and total TGF-beta1 and TNF-alpha were measured in type 2 diabetic patients with nephropathy (n = 23) or without (n = 35) and normoglycemic controls (n = 12). Serum levels of circulating active TGF-beta1 were significantly higher in patients with diabetic nephropathy (0.43 +/- 0.06 ng x mL(-1)) compared with diabetic patients without renal involvement (0.23 +/- 0.03 ng x mL(-1), P = .002) and healthy controls (0.24 +/- 0.03 ng x mL(-1), P= .001), whereas the levels of total (active + latent) TGF-beta1 were not different between the subgroups. Active TGF-beta1 concentrations were correlated with urinary albumin excretion (r = .49, P < .003) and serum creatinine (r= .55, P < .01). Sera from patients with type 2 diabetes contained significantly more TNF-alpha than sera from normoglycemic controls (3.07 +/- 0.24 v 1.65 +/- 0.20 pg x mL(-1), P = .001). However, the comparison of serum TNF-alpha concentrations between microalbuminuric and normoalbuminuric diabetic patients showed no significant difference (3.21 +/- 0.28 v 2.97 +/- 0.34 pg x mL(-1), P = .12). In conclusion, type 2 diabetic patients with diabetic nephropathy exhibit increased activation of TGF-beta1, in serum, suggesting an association between circulating TGF-beta1 activity and the development of renal disease.     

Increased levels of transforming growth factor-beta1 in essential hypertension

BACKGROUND: Transforming growth factor-beta (TGF-beta) is a multifunctional cytokine that has been linked to vascular remodeling processes, myocardial hypertrophy, and renal fibrosis. Recently a correlation between serum levels of TGF-beta1 and blood pressure (BP) levels in patients with end-stage renal disease was shown. In addition, it is not clear whether TGF-beta1 is a causative factor in the pathogenesis of essential hypertension and associated with hypertensive target organ damage (TOD). METHODS: Using a TGF-beta1-specific sandwich ELISA, we compared plasma levels of active and total TGF-beta1 of 30 normotensive persons and 85 patients with essential hypertension with and without TOD, as measured by microalbuminuria or left ventricular hypertrophy. RESULTS: Active and total TGF-beta1 levels were significantly higher in plasma of patients with essential hypertension than in normotensive controls (P < .05 and P < .01, respectively). However, neither active nor total TGF-beta1 correlated with systolic or diastolic BP (R2 < 0.14 for all parameters). Levels of active and total TGF-beta1 were significantly higher in hypertensive patients with than without TOD (P < .05). CONCLUSIONS: Active and latent TGF-beta1 levels are markedly increased in plasma of hypertensive patients. We assume that TGF-beta1 contributes substantially to the development of TOD in essential hypertension, independent of BP levels.     

日本血吸虫病肝纤维化小鼠肝脏CTGF、TGFβ_1-mRNA的表达及意义

目的研究结缔组织生长因子(connective tissue growth factor,CTGF)mRNA与转化生长因子-β1(transforminggrowth factor-beta1,TGFβ-1)mRNA在日本血吸虫病肝纤维化小鼠肝脏中的表达及意义。方法用昆明小鼠感染尾蚴复制小鼠日本血吸虫病肝纤维化模型,模型组分别在6、10、14、18周杀鼠,治疗组在6周时予吡喹酮治疗后10、14、18周杀鼠;masson染色并图像分析进行胶原半定量;RT-PCR检测小鼠肝脏CTGFmRNA、TGFβ-1mRNA表达。结果模型组10周时小鼠血吸虫病肝纤维化形成,胶原量进行性增加,肝脏CTGFmRNA表达达高峰,10周、14周、18周时与治疗组相比均有明显的统计学差异(P均<0.01);模型组TGFβ-1mRNA表达水平和CTGFmRNA有相同的变化趋势,但18周时与治疗组已无明显差别(P>0.05);模型组CTGFmRNA和TGF-β1mRNA的表达具有直线相关性。结论CTGF与TGF-β1的基因表达与小鼠日本血吸虫病肝纤维化形成有密切关系;TGF-β1的致纤维化作用可能部分通过CTGF的生物学作用介导;通过阻断CTGF的传导通路可能是肝纤维化治疗的有效靶点。     

Implication of transforming growth factor-beta1 in Chagas disease myocardiopathy

Cardiac dysfunction with progressive fibrosis is a hallmark of Chagas disease. To evaluate the involvement of transforming growth factor (TGF)-beta1 in this disease, TGF-beta1 levels in patients were measured at 3 stages: asymptomatic indeterminate (IND), cardiac with no or slight heart dysfunction (Card 1), and cardiac with moderate or severe heart dysfunction (Card 2). All patients had significantly higher circulating levels of TGF-beta1 than did healthy persons, and 27% of patients in the Card 1 group had higher TGF-beta1 levels than did patients in the IND group. Immunohistochemical analysis of cardiac biopsy specimens showed strong fibronectin staining in the extracellular matrix and staining for phosphorylated Smad 2 (activation of the TGF-beta1 signaling pathway) in cell nuclei. The higher levels of latent TGF-beta1 observed in patients with myocardiopathy, together with intracellular activation of the TGF-beta1 pathway and tissue fibrosis, suggest that TGF-beta1 plays an important role in Chagas disease. TGF-beta1 may represent a new target for preventive and curative treatments of Chagas disease.     

高迁移率族蛋白B1和α平滑肌肌动蛋白在支气管肺发育不良中的表达及意义

目的检测高迁移率族群蛋白B1（HMGB1）和α-平滑肌肌动蛋白（α-SMA）在中浓度高氧（60%O2）暴露新生小鼠肺组织损伤模型肺中的表达水平,探讨HMGB1在支气管肺发育不良（BPD）发病机制中的作用。方法新生足月C57BL/6小鼠随机分为氧处理组和空白对照组,制备中浓度高氧致新生鼠BPD模型,应用HE染色、放射性肺泡计数、免疫荧光和实时荧光定量-PCR技术观察生后第3、7、14天肺组织病理改变,HMGB1和α-SMA的蛋白及mRNA表达水平。结果氧处理组随时间推移,出现肺泡上皮肿胀,肺泡壁增厚,间质水肿,炎症细胞浸润,胶原样物质产生,较空白对照组明显发育迟滞。氧处理组HMGB1蛋白和mRNA在第7、14天时表达均强于相应空白对照组（P〈0.05）。氧处理组α-SMA蛋白和mRNA在第3、7、14天表达均强于相应空白对照组（P〈0.05）。HMGB1与α-SMA表达呈线性关系（P〈0.05）。结论在600 ml/L氧暴露所致BPD中,HMGB1和α-SMA表达增加。BPD的病理过程可能与HMGB1表达增加及α-SMA活化有关。     

转化生长因子β1和结缔组织生长因子在小鼠血吸虫病肝纤维化中的表达

目的建立血吸虫病肝纤维化小鼠模型,观察转化生长因子β1(TGF-β1)和结缔组织生长因子(CTGF)在小鼠血吸虫肝纤维化中的表达状况。方法 30只BALB/c小鼠随机分为模型组和对照组(每组15只),模型组小鼠以腹部贴片法经皮肤攻击感染日本血吸虫尾蚴(30±1)条,分别于感染后第4、6、8、10和12周两组各取3只小鼠摘眼球取血,测定血清中丙氨酸转氨酶(ALT)和天冬氨酸转氨酶(AST)水平;采血后处死小鼠取肝组织,常规切片,经HE染色后观察各组小鼠肝组织的病理学改变,Masson染色后观察肝组织胶原显微增生情况;免疫组织化学和荧光定量PCR方法检测小鼠肝组织中TGF-β1、CTGF的蛋白和mRNA表达水平。结果感染后6～12周,模型组的ALT和AST水平与同期对照组比较差异统计学意义(P<0.05)。感染12周时,模型组的ALT和AST水平分别为(173.53±31.12)U/L和(301.00±34.87)U/L均高于对照组的[(42.00±3.53)U/L和(96.58±11.26)U/L]。肝组织切片经HE染色后发现,模型组的肝组织有虫卵肉芽肿沉积.汇管区的纤维化特别明显,呈干线性纤维化改变,切面上见门静脉分支周围纤维组织增生呈树枝状分布;Masson染色显示,模型组的肝组织胶原纤维增生面积于感染后8周明显增加,感染后12周为(23.83±1.68)%,与对照组[(1.23±0.14)%]的比较,差异有统计学意义(P<0.05)。感染后10和12周,模型组的TGF-β1[(22.34±2.58)%和(25.82±3.01)%]和CTGF[(11.32±2.44)%和(14.51±2.05)%]的蛋白阳性区域面积与对照组[(2.56±0.87)%和(1.09±0.73)%]的比较,差异有统计学意义(P<0.05)。感染后6、8、10和12周,模型组的TGF-β1和CTGF mRNA相对转录水平呈上升趋势,与同时段对照组的比较差异均有统计学意义(P<0.05);其中在感染后10周时,TGF-β1 mRNA相对转录水平最高,为0.0721±0.0187,对照组的则为0.0089±0.0037;在感染后12周时,CTGF mRNA相对转录水平最高,为0.1136±0.0365,对照组的则为0.0293±0.0184;CTGF mRNA相对转录水平与日本血吸虫感染时间有明显的相关性(r=0.927,P<0.05)。结论 BALB/c小鼠感染日本血吸虫后,肝组织中TGF-β1和CTGF蛋白阳性表达类型和表达分布区域基本一致,CTGF mRNA的相对转录水平与日本血吸虫感染时间有明显相关性。     

Hypoxia-inducible factor-1 transactivates transforming growth factor-beta3 in trophoblast

Hypoxia occurs during the development of placenta in the first trimester and is implicated in trophoblast differentiation. Intervillous blood flow increases after 10 wk of gestation and results in exposure of trophoblast cells to oxygen. Before this time, low oxygen appears to prevent trophoblast differentiation toward an invasive phenotype. The oxygen-regulated early events of trophoblast differentiation are mediated by TGF-beta3. TGF-beta3 plays a vital role in trophoblast differentiation, and its overexpression can be found in preeclamptic placenta. We sought to determine the mechanism of TGF-beta3 expression through hypoxia-inducible factor (HIF)-1. We show that HIF-1alpha and TGF-beta3 are overexpressed in preeclamptic placenta. Hypoxia not only transactivates the TGF-beta3 promoter activity but also enhances endogenous TGF-beta3 expression. Using the TGF-beta3 promoter deletion mutants, we show that the region between -90 and -60, which contains a putative HIF-1 consensus motif, is crucial for HIF-1-mediated transactivation. Electrophoretic mobility shift assays show that HIF-1 binds to the oligonucleotide containing the HIF-1 motif. Also, introduction of an antisense oligonucleotide for HIF-1 diminishes TGF-beta3 expression during hypoxia, indicating that the up-regulation of TGF-beta3 by hypoxia is mediated through HIF-1. Our results provide evidence that regulation of TGF-beta3 promoter activity by HIF-1 represents a mechanism for trophoblast differentiation during hypoxia.     

Valvular myofibroblast activation by transforming growth factor-beta: implications for pathological extracellular matrix remodeling in heart valve disease

The pathogenesis of cardiac valve disease correlates with the emergence of muscle-like fibroblasts (myofibroblasts). These cells display prominent stress fibers containing alpha-smooth muscle actin (alpha-SMA) and are believed to differentiate from valvular interstitial cells (VICs). However, the biological factors that initiate myofibroblast differentiation and activation in valves remain unidentified. We show that transforming growth factor-beta1 (TGF-beta1) mediates differentiation of VICs into active myofibroblasts in vitro in a dose-dependent manner, as determined by a significant increase in alpha-SMA and the dramatic augmentation of stress fiber formation and alignment. Additionally, TGF-beta1 and increased mechanical stress function synergistically to enhance contractility. In turn, contractile valve myofibroblasts exert tension on the extracellular matrix, resulting in a dramatic realignment of extracellular fibronectin fibrils. TGF-beta1 also inhibits valve myofibroblast proliferation without enhancing apoptosis. Our results are consistent with activation of a highly contractile myofibroblast phenotype by TGF-beta1 and are the first to connect valve myofibroblast contractility with pathological valve matrix remodeling. We suggest that the activation of contractile myofibroblasts by TGF-beta1 may be a significant first step in promoting alterations to the valve matrix architecture that are evident in valvular heart disease.