Role of transforming growth factor beta in conjunctival scarring

Glaucoma is the major cause of irreversible blindness throughout the world. Of all of the treatments that are available at present, the most effective appears to be surgery; however, excessive conjunctival scarring can lead to surgical failure. In the last decade, the introduction of the anti-metabolites mitomycin-C and 5-fluorouracil as anti-scarring treatments have greatly improved the results of glaucoma surgery, but these agents are associated with complications that can potentially result in blindness. A possible target for a more physiological approach to anti-scarring is transforming growth factor beta. This review examines the role of transforming growth factor beta in conjunctival scarring and discusses promising new ways of modifying its activity.     

Role of transforming growth factor beta in rat bladder smooth muscle cell proliferation

Conditions associated with hypertrophy of the urinary bladder have repeatedly been associated with an increased urinary excretion of transforming growth factor (TGF) beta in both rats and patients. Because TGFbeta can have both growth-promoting and -inhibiting effects, we have studied its effects on cell growth and death in primary cultures of rat bladder smooth muscle cells. TGFbeta1, TGFbeta2, or TGFbeta3 did not cause apoptosis, but all three isoforms inhibited DNA synthesis with similar potency (EC(50) of approximately 0.1 ng/ml) and efficacy. Such inhibition was antagonized by a specific TGFbeta receptor antagonist and independent of the presence of serum. Mitogen-activated protein kinases (MAPKs) are involved in the control of cell growth, and all three TGFbeta isoforms inhibited activation of the extracellular signal-regulated kinase, c-Jun NH(2)-terminal kinase, and p38 MAPK subfamilies. Nevertheless, the inhibitory effects of the TGFbeta isoforms on DNA synthesis were not affected by presence of inhibitors of the three MAPK pathways. TGFbeta did not alter cell size as measured by flow cytometry or mitochondrial activity, an integrated measure of cell size and number. We conclude that our data do not support the hypothesis that TGFbeta is a mediator of rat bladder hypertrophy.     

软骨形成过程中的转化生长因子β2

背景：转化生长因子β2是一族多肽类生长因子,具有多重生物学效应,对骨髓间充质干细胞增殖分化功能有一定促进作用,是调节骨髓间充质干细胞增殖和向软骨细胞方向分化的最主要因子之一。目的：探讨转化生长因子β2的分子结构特点及其在软骨形成方面的作用。方法：应用计算机检索中国期刊全文数据CNKI、中国期刊全文数据维普中文科技期刊数据库（VIP）和PubMed数据库（1995-01/2011-08）与骨组织工程中转化生长因子β2诱导软骨形成有关的文章,检索词分别为＂转化生长因子β2;软骨细胞分化;骨组织工程＂和＂TGF-β2;cartilage formation;tissue engineering＂。纳入所述内容与转化生长因子β2分子结构特点,转化生长因子β2信号转导通路,软骨细胞的诱导性分化,软骨性疾病的生物性治疗进展有关。排除综述文献、重复研究、观点陈旧的文章。结果与结论：初检得到302篇文献,排除262篇不符合标准的文献,共纳入40篇符合标准的文献。经分析得出转化生长因子β2通过促进骨髓间充质干细胞分化为软骨细胞促进软骨特异性基质如Ⅱ型胶原及蛋白多糖的合成,从而发挥软骨诱导作用。转化生长因子β2与其他因子共同作用调节软骨细胞生长分化,使临床上永久性修复软骨组织缺损的治疗变为可能。     

软骨形成过程中的转化生长因子

背景:转化生长因子β2 是一族多肽类生长因子,具有多重生物学效应,对骨髓间充质干细胞增殖分化功能有一定促进作用,是调节骨髓间充质干细胞增殖和向软骨细胞方向分化的最主要因子之一.目的:探讨转化生长因子β2 的分子结构特点及其在软骨形成方面的作用.方法:应用计算机检索中国期刊全文数据CNKI、中国期刊全文数据维普中文科技期刊数据库(VIP)和PubMed 数据库(1995-01/2011-08)与骨组织工程中转化生长因子β2 诱导软骨形成有关的文章,检索词分别为"转化生长因子β2;软骨细胞分化;骨组织工程"和"TGF-β2;cartilage formation;tissue engineering".纳入所述内容与转化生长因子β2 分子结构特点,转化生长因子β2 信号转导通路,软骨细胞的诱导性分化,软骨性疾病的生物性治疗进展有关.排除综述文献、重复研究、观点陈旧的文章.结果与结论:初检得到302 篇文献,排除262 篇不符合标准的文献,共纳入40 篇符合标准的文献.经分析得出转化生长因子β2 通过促进骨髓间充质干细胞分化为软骨细胞促进软骨特异性基质如Ⅱ型胶原及蛋白多糖的合成,从而发挥软骨诱导作用.转化生长因子β2 与其他因子共同作用调节软骨细胞生长分化,使临床上永久性修复软骨组织缺损的治疗变为可能.     

Differential regulation of mesothelial cell fibrinolysis by transforming growth factor beta 1

Management of hypertension and diabetes mellitus in primary health care requires occasional assessment of kidney function. Monitoring the urinary albumin excretion every 24?h is often used as a diagnostic gold standard but measurement of U‐Albumin concentrations in morning urine either alone or together with U‐Creatinine is a well‐established surrogate measure. We compared the ratio U‐Albumin/U‐Creatinine and U‐Albumin concentrations measured by commonly used POC (Point of care) instruments with those obtained in a central laboratory and estimated the uncertainty of the results after establishing an uncertainty budget. It is concluded that the presentation of ratios or concentrations on an ordinal scale is less satisfactory than reporting U‐Albumin concentration on a ratio scale. Moreover the latter will have the advantage of allowing the physician to adjust the diagnostic sensitivity and specificity to local needs. The present report is a methodological study and does not consider the diagnostic performance of the studied properties per se.     

Dog mastocytoma cells produce transforming growth factor beta 1.

Transforming growth factor-beta (TGF beta) promotes deposition of extracellular matrix and is associated with fibrotic conditions both in experimental animals and in humans. Although a role for mast cells has been suspected in the pathogenesis of fibrosis, no potent mediator capable of stimulating fibroblast growth or extracellular matrix deposition has been identified in mast cell supernatants. We report here the constitutive production of TGF beta 1 by four dog mastocytoma cell lines. TGF beta 1 was identified by characteristic biologic activity, blockade of biologic effect by specific neutralizing antibody, and by recognition of a band with the appropriate migration by western blot. TGF beta 1 mRNA, but not TGF beta 2 or TGF beta 3 mRNA, was also produced constitutively by all four cell lines. Quantitation by bioassay revealed baseline TGF beta secretion of approximately 1 ng/10(6) cells over 48 h. Stimulation of mastocytoma cells with phorbol ester increased the rate of release of TGF beta 1, most markedly in the first 30 min after stimulation, without increasing TGF beta 1 mRNA. Dog mastocytoma cells produced TGF beta 1 primarily in a latent form, inactive until treated with acid. Both pure TGF beta 1 and TGF beta-containing mastocytoma cell-conditioned media inhibited mitogenesis and proliferation in dog mastocytoma cell lines, suggesting that mast cell tumor lines would not grow preferentially based on their ability to produce TGF beta. These studies may make possible further investigation of the mechanism by which mast cells contribute to the induction of fibrosis.     

Requirement for transforming growth factor beta1 in controlling T cell apoptosis

Transforming growth factor (TGF)-beta1, a potent immunoregulatory molecule, was found to control the life and death decisions of T lymphocytes. Both thymic and peripheral T cell apoptosis was increased in mice lacking TGF-beta1 (TGF-beta1(-/-)) compared with wild-type littermates. Engagement of the T cell receptor enhanced this aberrant T cell apoptosis, as did signaling through either the death receptor Fas or the tumor necrosis factor alpha receptor in peripheral T cells. Strikingly, TGF-beta was localized within the mitochondria of normal T cells, and the absence of TGF-beta1 resulted in disruption of mitochondrial membrane potential (Deltapsi(m)), which marks the point of no return in a cell condemned to die. This TGF-beta-dependent regulation of viability appears dissociable from the TGF-beta1 membrane receptor-Smad3 signaling pathway, but associated with a mitochondrial antiapoptotic protein Bcl-XL. Thus, TGF-beta1 may protect T cells at multiple sites in the death pathway, particularly by maintaining the essential integrity of mitochondria. These findings may have broad implications not only for T cell selection and death in immune responses and in the generation of tolerance, but also for defining the mechanisms of programmed cell death in general.     

Cell contact-dependent immunosuppression by CD4(+)CD25(+) regulatory T cells is mediated by cell surface-bound transforming growth factor beta

CD4(+)CD25(+) T cells have been identified as a population of immunoregulatory T cells, which mediate suppression of CD4(+)CD25(-) T cells by cell-cell contact and not secretion of suppressor cytokines. In this study, we demonstrated that CD4(+)CD25(+) T cells do produce high levels of transforming growth factor (TGF)-beta1 and interleukin (IL)-10 compared with CD4(+)CD25(-) T cells when stimulated by plate-bound anti-CD3 and soluble anti-CD28 and/or IL-2, and secretion of TGF-beta1 (but not other cytokines), is further enhanced by costimulation via cytotoxic T lymphocyte-associated antigen (CTLA)-4. As in prior studies, we found that CD4(+)CD25(+) T cells suppress proliferation of CD4(+)CD25(-) T cells; however, we observed here that such suppression is abolished by the presence of anti-TGF-beta. In addition, we found that CD4(+)CD25(+) T cells suppress B cell immunoglobulin production and that anti-TGF-beta again abolishes such suppression. Finally, we found that stimulated CD4(+)CD25(+) T cells but not CD4(+)CD25(-) T cells express high and persistent levels of TGF-beta1 on the cell surface. This, plus the fact that we could find no evidence that a soluble factor mediates suppression, strongly suggests that CD4(+)CD25(+) T cells exert immunosuppression by a cell-cell interaction involving cell surface TGF-beta1.     

转化生长因子β1在血管损伤后再狭窄形成中的作用

转化生长因子β1是一种高度多效、多功能性的生长与分化因子,它广泛地调节机体的生长、发育、炎症、修复和免疫等许多生理和病理过程。当血管损伤后,局部产生的细胞因子引起炎症反应是血管再狭窄的主要原因。其中,转化生长因子β1在局部水平上调刺激平滑肌细胞增殖和迁移、促进动脉外膜细胞的表型改变和迁移以及局部细胞外基质蛋白的产生和沉积,从而促进血管再狭窄。本文从转化生长因子β1的生物学特性、血管损伤后再狭窄的病理学、转化生长因子β1与血管损伤后再狭窄相关性及转化生长因子β1对血管损伤后再狭窄的作用机制等方面进行综述,说明转化生长因子β1在血管损伤后再狭窄病理过程中所起的作用。     

Plasmid DNA encoding transforming growth factor-beta1 suppresses chronic disease in a streptococcal cell wall-induced arthritis model.

Transforming growth factor beta is a potent immunomodulator with both pro- and antiinflammatory activities. Based on its immunosuppressive actions, exogenous TGF-beta has been shown to inhibit autoimmune and chronic inflammatory diseases. To further explore the potential therapeutic role of TGF-beta, we administered a plasmid DNA encoding human TGF-beta1 intramuscularly to rats with streptococcal cell wall-induced arthritis. A single dose of 300 microg plasmid DNA encoding TGF-beta1, but not vector DNA, administered at the peak of the acute phase profoundly suppressed the subsequent evolution of chronic erosive disease typified by disabling joint swelling and deformity (articular index = 8.17+/-0. 17 vs. 1.25+/-0.76, n = 6, day 26, P < 0.01). Moreover, delivery of the TGF-beta1 DNA even as the chronic phase commenced virtually eliminated subsequent inflammation and arthritis. Both radiologic and histopathologic as well as molecular evidence supported the marked inhibitory effect of TGF-beta1 DNA on synovial pathology, with decreases in the inflammatory cell infiltration, pannus formation, cartilage and bone destruction, and the expression of proinflammatory cytokines that characterize this model. Increases in TGF-beta1 protein were detected in the circulation of TGF-beta1 DNA-treated animals, consistent with the observed therapeutic effects being TGF-beta1 dependent. These observations provide the first evidence that gene transfer of plasmid DNA encoding TGF-beta1 provides a mechanism to deliver this potent cytokine that effectively suppresses ongoing inflammatory pathology in arthritis.     

Retinoic acid modulates rat Ito cell proliferation, collagen, and transforming growth factor beta production.

Recent studies suggest that vitamin A plays an inhibitory role with respect to "activation" of the hepatic Ito cell, a likely effector of hepatic fibrogenesis. Ito cell "activation" during fibrogenesis is characterized by a decrease in intracellular vitamin A and an increase in cellular proliferation and collagen production. To explore the hypothesis that retinoids have the capacity to diminish Ito cell activation, cultured Ito cells were exposed to retinoic acid and its effects assessed on three key features: cell proliferation, collagen protein production and mRNA abundance, and transforming growth factor beta protein production. Retinoic acid was 100-1,000X more potent than retinol with respect to inhibition of Ito cell proliferation. Interstitial collagen and transforming growth factor beta production were also reduced by 10(-6) M retinoic acid. The relative abundance of type I collagen mRNA however, was not significantly altered. By contrast, retinoic acid administration to rats caused a marked reduction in the abundance of type I collagen mRNA in both total hepatic and purified Ito cell RNA. The relative abundance of rat hepatic fibronectin or apolipoprotein E mRNA was not significantly altered. These studies demonstrate that retinoic acid can differentially modulate several key features of hepatic fibrogenesis in vitro and in vivo.     

转化生长因子β1质粒对静脉移植的影响

背景:大量实验表明,转化生长因子β1质粒在神经移植过程中可抑制或减弱移植排斥反应,而对静脉移植的影响却很少有行报道.目的:探讨大鼠局部注射转化生长因子β1质粒诱导同种异体异基因股静脉移植免疫耐受的作用途径.设计、时间及地点:随机分组,动物实验观察,于2007-03/2008-04在哈尔滨医科大学动物实验中心完成.材料:供体Wistar大鼠18只,受体SD大鼠48只随机分为自体移植组,异体移植组,免瘦抑制剂组,转化生长因子β1质粒组,每组12只.方法:免疫抑制剂组在移植前3 d开始腹腔内注射环孢霉素A(10 mg/kg),1次,d,直到处死.转化生长因子β1质粒组大鼠于局部股静脉两断端内注射40 μg/只的转化生长因子β1质粒.自体移植和异体移植组仅进行静脉移植.主要观察指标:于2周后进行影像学、组织学、免疫学检测.结果:自体移植组:内皮细胞扁平,核膜增厚.异体移植组;脱落内皮细胞及碎片,可见内膜下层.免疫抑制剂组:血管内皮细胞核膜增厚,广泛粗面内质网扩张.转化生长因子β1质粒组:血管内皮细胞可见粗面内质网扩张,线粒体空泡变.相邻细胞间可见紧密连接.转化生长因子β1质粒组优于免疫抑制剂组和异体移植组.4组混合淋巴细胞培养A值分别为1.07±0.14、4.15±0.67、1.77±0.23和1.38±0.23.转化生长因子β1质粒组与异体血管移植组和免疫抑制剂组比较,有显著差异(P<0.05).异体血管移植组对供体大鼠淋巴细胞的刺激呈正常反应,转化生长因子β1质粒组对供体鼠淋巴细胞的刺激反应性减弱,与免疫抑制剂组比较,差异有显著性意义(P<0.05).结论:局部注射转化生长因子β1质粒可以协同减轻移植后产生的免疫排斥反应.     

Recombinant latent transforming growth factor beta 1 has a longer plasma half-life in rats than active transforming growth factor beta 1, and a different tissue distribution.

Transforming growth factor beta 1 (TGF-beta 1) is a key regulator of cell growth and differentiation. Under normal physiological conditions, it is made as a biologically latent complex whose significance is unknown. Previous work has indicated that active TGF-beta 1 has a very short plasma half-life in rats (Coffey, R. J., L. J. Kost, R. M. Lyons, H. L. Moses, and N. F. La-Russo. 1987. J. Clin. Invest. 80:750-757). We have investigated the possibility that latent complex formation may extend the plasma half-life of TGF-beta 1 and alter its organ distribution. Radiolabeled latent TGF-beta 1 was formed by noncovalent association of 125I-TGF-beta 1 with the TGF-beta 1 precursor "pro" region from recombinant sources. TGF-beta 1 in this latent complex had a greatly extended plasma half-life (greater than 100 min) in rats compared with active TGF-beta 1 (2-3 min). Whereas active TGF-beta 1 was rapidly taken up by the liver, kidneys, lungs, and spleen and degraded, TGF-beta 1 in the latent complex was largely confined to the circulation, and was less than 5% degraded after 90 min. The pharmacokinetics of TGF-beta 1 in the latent complex were shown to be critically dependent on the degree of sialylation of the complex. The results suggest that formation of latent complexes may switch endogenous TGF-beta 1 from an autocrine/paracrine mode of action to a more endocrine mode involving target organs distant from the site of synthesis.     

转化生长因子β及骨形态发生蛋白7修复膝关节软骨损伤中的应用与作用

目的:通过总结和分析关节软骨损伤修复相关方面的研究,阐述了转化生长因子β、骨形态发生蛋白7在膝关节软骨损伤修复中的价值和作用,为今后临床应用提供重要的参考依据.资料来源:以Articular Cartilage Defects,Transforming Growth Factor-β,Bone Morphogenic Protein-7为检索词,检索science online,ElsecierSD数据库,Springer Link电子期刊网等(1991-01/2009-06);以关节软骨损伤,转化生长因子13,骨形态发生蛋白7为检索词,检索中国知网,万方数据库,清华同方数据库(1991-0112009-06).文献检索语种限制为英文和中文.资料选择:纳入与生长因子有关的修复关节软骨损伤的文献,排除重复文献.结局评价指标:①骨折的愈合情况.②骨细胞的增殖情况.③软骨形成的能力.结果:计算机初检得到95篇文献,根据纳入排除标准,对生长因子对尤其是转化生长因子β及骨形态发生蛋白7修复膝关节软骨损伤的文献进行分析.关节软骨损伤在运动员中非常多见,并且关节中的软骨组织修复能力较差.由于一旦损伤即产生永久性病变,且关节软骨损伤的传统治疗方法效果不显著,治疗的困难是运动医学亟待解决的问题.转化生长因子β是调节软骨形成的重要因子,对多种细胞具有刺激或抑制作用.通过提高软骨细胞的敏感性,在骨性关节炎的软骨损伤修复过程中起着中枢的作用,同时对体外软骨细胞的蛋白合成有调节作用,在诱导特殊肉芽组织方面也有重要作用.骨形态发生蛋白7能诱导间充质来源软骨和创面周围软骨产生特异性胶原及黏蛋白,对促进软骨损伤的修复具有明显的作用.结论:转化生长因子β及骨形态发生蛋白7对膝关节软骨损伤有一定的作用,但是二者联合是否会促进关节软骨损伤的修复,有待于今后进一步的实验研究.     

血管平滑肌细胞增殖与转化生长因子β/smads的表达

目的:观察增殖和分化两种血管平滑肌细胞表型改变与转化生长因子β/smads信号传递的关系。方法:实验于2003-09/10哈尔滨医科大学医学遗传学研究室完成。取体质量200g左右的健康雄性SD大鼠,常规胶原酶消化法原代培养大鼠血管平滑肌细胞。用体积分数为0.2和0.05(去血清培养)胎牛血清和的Dulbecco改良的Eagle培养基,37℃,体积分数0.05CO2进行培养,2.5g/L胰酶消化传代。血管平滑肌细胞经锥虫蓝染色,存活细胞数在98%以上。形态学上出现典型的“峰和谷”样生长状态,抗平滑肌特异α-肌动蛋白免疫组织化学染色阳性。取3～8代细胞用于实验。流式细胞分析检测不同表型血管平滑肌细胞增殖能力,蛋白质印迹分析方法检测血管平滑肌细胞分化相关基因平滑肌特异性肌动蛋白表达变化,反转录聚合酶链反应和细胞免疫荧光方法检测转化生长因子βI型受体,smad2,smad3,smad4和smad7的表达变化。结果:①流式细胞分析及蛋白印迹分析方法检测发现,去血清培养后,原代培养大鼠血管平滑肌细胞增殖能力下降;DNA合成前期细胞明显增加犤(52.42±2.35)%犦,细胞分化基因平滑肌特异性α-肌动蛋白明显表达。体积分数为0.2胎牛血清培养后,大鼠血管平滑肌细胞增殖旺盛,DNA合成前期细胞数相对较少犤(17.23±1.58)%犦,细胞分化相关基因平滑肌特异性肌动蛋白表达明显下调。②反转录聚合酶链反应和细胞免疫荧光方法检测发现,去血清培养后的分化表型平滑肌细胞中,转化生长因子βI型受体表达增加,smad2和smad3表达无明显变化,smad4表达增加,smad7表达下降。而高血清培养诱导平滑肌细胞转化为增殖表型后,转化生长因子βI型受体表达下降,smad4表达下降,抑制型smad7表达增加,smad2和smad3表达无明显变化。结论:转化生长因子β/smads表达与血管平滑肌细胞表型状态密切相关。血管平滑肌细胞分化时,可能通过转化生长因子βI型受体/smad4调控细胞分化功能;而血管平滑肌细胞增殖时,细胞则可能通过smad7信号传导通路发挥作用。提示转化生长因子β/smads在血管平滑肌细胞由合成表型逆转为分化表型的分子调控中发挥作用。     

深低温冻存同种异体皮肤移植中转化生长因子β的表达

背景：皮肤移植和创面覆盖是创伤、烧伤治疗的重要措施。目前,同种异体皮仍然是可利用的最佳创面覆盖物。目的：通过检测转化生长因子β在深低温冻存后的大鼠同种异体皮肤移植后的表达,评估深低温贮存同种异体皮在创面上的应用。方法：取大鼠皮肤保存于低温-20℃（低温保存组）及80℃深低温（深低温保存组）,冻存1周、1,2个月后,皮片分组移植于同种大鼠背部进行实验,并以自体移植大鼠作为对照组。结果与结论：同低温保存组相比,深低温保存组转化生长因子β的表达被抑制,移植皮肤排斥反应出现时间延迟及存活时间延长,排斥反应评分也较低。同低温冻存相比,深低温冷冻保存能使同种异体移植物的转化生长因子β抗原表达降低。提示深低温冻存的异体皮作为一种创面临时覆盖物,在存在皮肤组织缺失或皮源不足的情况下具有广阔的应用前景。     

转化生长因子β在纤维化疾病中的研究与应用

纤维化疾病如肺纤维化,肝硬化,肾小球硬化,骨髓纤维化,增生性瘢痕等在临床上比较常见,其发病因素和临床表现各不相同,但他们最终的病理特征是细胞外基质在组织器官内过度沉积所致的纤维化,大量研究表明许多细胞因子在纤维化疾病的纤维化过程中发挥重要的作用,其中转化生长因子β(TGF-β)在绝大多数的纤维化疾病过程中发挥着关键作用。TGF-β是一种具有多种生物学效应的生长调节因子,在细胞因子网络中占主导地位,它通过各种途径促进细胞外基质在组织器官内沉积有利于损伤的修复,但其持续性过度表达就会导致组织器官的过度纤维化,TGF-β水平在人体多种组织器官纤维化疾病中显著增高。TGF-β通过调控细胞外基质生成细胞的转录或转录后水平,促进各种细胞外基质表达,并能诱导成纤维细胞等多种细胞合成和分泌细胞外基质蛋白并抑制其降解。了解TGF-β的生物学效应及其在纤维化疾病中的各个作用环节,为应用TGF-β的抑制剂及其抗体等抗纤维化治疗提供更好的依据。