Effect of ulcerative colitis activity on plasma concentration of transforming growth factor beta1

Enhanced expression of transforming growth factor-beta1 (TGF-beta1) demonstrated in human colonic mucosa of patients with ulcerative colitis (UC), indicates its possible significance in the pathogenesis of this disease. The aim of this study was to evaluate plasma TGF-beta1 concentration in patients with different degrees of colonic mucosal injury, as a possible indicator of ulcerative colitis activity. TGF-beta1 concentration was measured with an enzyme immunoassay (EIA) in plasma of 45 patients with endoscopically confirmed UC. Values observed in UC patients (40.5+/-15.9 ng/ml) were significantly higher than in healthy people (18.3+/-11.6 ng/ml) and higher than in patients with irritable colon syndrome (ICS), (20.5+/-13.6 ng/ml). The highest plasma TGF-beta1 (58.6+/-112.1 ng/ml) was in patients with the severe UC course. TGF-beta1 level analysed in all UC patients revealed significant positive correlation with scored degree of mucosal injury (r=0.396;P<0.01). Among other possible laboratory markers of the disease activity, only C-reactive protein concentration demonstrated significant correlation. Enhanced production of TGF-beta1 can be related to inflammation activity. Measurement of plasma TGF-beta1 may be considered as a biomarker of the disease activity.     

Association between psoriasis severity and transforming growth factor beta(1) and beta (2) in plasma and scales from psoriatic lesions

Psoriasis is an inflammatory skin disorder with hyperproliferation of keratinocytes, that can be the result of insufficient inhibitory effect of transforming growth factors-beta (TGF-beta). The aim of this study was to evaluate an association between TGF-beta(1) and -beta(2) in plasma or scales from psoriatic lesions and the severity of the disease. TGF-beta concentrations were measured with an enzyme immunoassay in 41 patients with psoriasis. The mean plasma concentrations of TGF-beta(1) and TGF-beta(2) in patients were: 15.7 +/- 1.4 and 0.15 +/- 0.02 ng/ml respectively. It was also detectable in scales and varied from 24 to 1159 and from 0 to 2.95 pg/mg protein respectively. Plasma TGF-beta(1) correlated significantly with psoriasis area and severity index (PASI). Significant correlation was also demonstrated between TGF-beta(1) concentration in scales and sedimentation rate or the disease duration. There were no correlation between PASI and plasma TGF-beta(2), scales TGF-beta(1) and TGF-beta(2). The highest mean concentration of TGF-beta(1) in scales of patients with mild form of the disease (203 +/- 65 pg/mg protein) and the lowest in severe form (147 +/- 54 pg/mg protein) have been shown. These findings demonstrated association between PASI and plasma levels of TGF-beta(1), that should be considered as a possible indicator of psoriasis activity.     

The effect of Pygeum africanum on fibroblast growth factor (FGF) and transforming growth factor beta (TGF beta 1/LAP) expression in animal model

On the basis of its fibroblast growth factor (FGF) inhibitory effect we assessed the possible inhibitory anti-inflammatory role of Pygeum Africanum extract (Tadenan) on FGF and transforming growth factor beta (TGF beta 1/LAP) expression of macrophages and neutrophils in broncho-alveolar lavage fluid (BAL) of rats in a bleomycin-induced acute inflammation model. The rats were divided into three groups: 17 untreated controls, 10 bleomycin-instilled rats, receiving NaCl (0.9%), and 10 rats receiving Pygeum Africanum extract. On the 12th (and 15th day) we performed BAL and after labelling of cells expression of FGF and TGF beta 1 (LAP) was measured by flow-cytometry. We made a quantitative analysis of BAL cells as well. One-way ANOVA was used for statistical analysis. We found in Pygeum Africanum extract treated group 1, a significantly decreased number of neutrophil granulocytes (p < 0.05) compared with other groups 2, there was a considerable decrease (not significant) in expression of TGF beta 1(LAP) on BAL macrophages, but not in case of FGF. In conclusion: our results show the possible 1. inhibitory effect of this drug on TGF beta 1 (LAP) expression, 2. anti-inflammatory role on neutrophil granulocytes.     

Effect of transforming growth factor beta on fibroblasts in three-dimensional lattice cultures

Human skin fibroblasts were cultivated in three-dimensional fibrin or collagen lattices, under retracting or non-retracting conditions, and the influence of transforming growth factor beta (TGF beta) was tested. TGF beta stimulated the synthesis of non-collagen protein and of collagen in all the systems. However, only in non-retracting fibrin lattices did it restore a level of protein synthesis comparable to that found in monolayers. The effects of TGF beta greatly depended on the type of substratum and on the presence or absence of retraction.     

Modulation of transforming growth factor beta signalling pathway genes by transforming growth factor beta in human osteoarthritic chondrocytes: involvement of Sp1 in both early and late response cells to transforming growth factor beta

Introduction  

Transforming growth factor beta (TGFβ) plays a central role in morphogenesis, growth, and cell differentiation. This cytokine is particularly important in cartilage where it regulates cell proliferation and extracellular matrix synthesis. While the action of TGFβ on chondrocyte metabolism has been extensively catalogued, the modulation of specific genes that function as mediators of TGFβ signalling is poorly defined. In the current study, elements of the Smad component of the TGFβ intracellular signalling system and TGFβ receptors were characterised in human chondrocytes upon TGFβ1 treatment.     

Renal transforming growth factor beta 1 production in neonate rats

Abstract. The newborn rat kidney is not fully developed until approximately 12 days after birth. In order to evaluate the possible role of Transforming Growth Factor beta 1 (TGF beta 1) in renal development we analyzed the mRNA level for TGF beta 1 in sixty Wistar rats aged 1,15 and 30 days. We also performed immunohislochemical studies to visualize the distribution of this peptide in the kidney of these rats using a TGF beta 1 antibody. The results show that the mRNA levels for TGF beta 1 are higher in the kidneys of the 1-day-old rats than in the 15 (1.4 fold) and 30-day-old rats (1.7 fold). The immunohistochemical reaction revealed the presence of TGF beta in the kidneys of the rats. The staining intensity was higher in the renal cortex than in the medulla. The data suggests that TGF beta may be important during kidney development.     

Skeletal tissue and transforming growth factor beta

Normal skeletal growth results from a balance between the processes of bone matrix synthesis and resorption. These activities are regulated by both systemic and local factors. Bone turnover is dynamic, and skeletal growth must be maintained throughout life. Although many growth promoters are associated with bone matrix, it is enriched particularly with transforming growth factor beta (TGF-beta) activity. Experimental evidence indicates that TGF-beta regulates replication and differentiation of mesenchymal precursor cells, chondrocytes, osteoblasts, and osteoclasts. Recent studies further suggest that TGF-beta activity in skeletal tissue may be controlled at multiple levels by other local and systemic agents. Consequently, the intricate mechanisms by which TGF-beta regulates bone formation are likely to be fundamental to understanding the processes of skeletal growth during development, maintenance of bone mass in adult life, and healing subsequent to bone fracture.     

Requirement of Ras/MAPK pathway activation by transforming growth factor beta for transforming growth factor beta 1 production in a Smad-dependent pathway

Our previous results have shown that transforming growth factor beta (TGFbeta) rapidly activates Ras, as well as both ERKs and SAPKs. In order to address the biological significance of the activation of these pathways by TGFbeta, here we examined the role of the Ras/MAPK pathways and the Smads in TGFbeta(3) induction of TGFbeta(1) expression in untransformed lung and intestinal epithelial cells. Expression of either a dominant-negative mutant of Ras (RasN17) or a dominant-negative mutant of MKK4 (DN MKK4), or addition of the MEK1 inhibitor PD98059, inhibited the ability of TGFbeta(3) to induce AP-1 complex formation at the TGFbeta(1) promoter, and the subsequent induction of TGFbeta(1) mRNA. The primary components present in this TGFbeta(3)-inducible AP-1 complex at the TGFbeta(1) promoter were JunD and Fra-2, although c-Jun and FosB were also involved. Furthermore, deletion of the AP-1 site in the TGFbeta(1) promoter or addition of PD98059 inhibited the ability of TGFbeta(3) to stimulate TGFbeta(1) promoter activity. Collectively, our data demonstrate that TGFbeta(3) induction of TGFbeta(1) is mediated through a signaling cascade consisting of Ras, the MAPKKs MKK4 and MEK1, the MAPKs SAPKs and ERKs, and the specific AP-1 proteins Fra-2 and JunD. Although Smad3 and Smad4 were not detectable in TGFbeta(3)-inducible AP-1 complexes at the TGFbeta(1) promoter, stable expression of dominant-negative Smad3 could significantly inhibit the ability of TGFbeta(3) to stimulate TGFbeta(1) promoter activity. Transient expression of dominant-negative Smad4 also inhibited the ability of TGFbeta(3) to transactivate the TGFbeta(1) promoter. Thus, although the Ras/MAPK pathways are essential for TGFbeta(3) induction of TGFbeta(1), Smads may only contribute to this biological response in an indirect manner.     

Anti-immunoglobulin treatment of murine B-cell lymphomas induces active transforming growth factor beta but pRB hypophosphorylation is transforming growth factor beta independent.

Cross-linking of B-cell membrane immunoglobulin (Ig) receptors induces growth arrest at G1-S, leading to apoptosis and cell death in the immature lymphomas WEHI-231 and CH31, but not in the CH12 B-cell line. In this system, which has been used as a model for B-cell tolerance, we have established that these lymphomas produce active transforming growth factor beta (TGF-beta) when treated with anti-Ig and that their hierarchy of sensitivity to TGF-beta generally correlates with their growth inhibition by anti-Ig. TGF-beta, in turn, has been shown to interfere with the phosphorylation of the retinoblastoma gene product, pRB. Herein, we also demonstrate that in WEHI-231 B-lymphoma cells treated with anti-Ig for 24 h, the pRB protein is found to be predominantly in the underphosphorylated form, as previously reported for cells arrested by the exogenous addition of TGF-beta. However, neutralizing antibodies to TGF-beta failed to prevent growth inhibition by anti-Ig in WEHI-231 and CH31. When WEHI-231 lymphoma cells were selected for growth in TGF-beta, the majority of the TGF-beta-resistant clones remained sensitive to anti-Ig-mediated growth inhibition. In these clones, the retinoblastoma gene product was found to be in the underphosphorylated form after 24-h treatment with anti-Ig, but not with TGF-beta. These data show that anti-Ig treatment of murine B-cell lymphomas stimulates the production of active TGF-beta but that a TGF-beta-independent pathway may be responsible for the pRB underphosphorylation and cell cycle blockade.     

Effect of platelet-derived transforming growth factor (TGF) type beta 1 on murine inflammatory mononuclear phagocytes: increased fibronectin production

The effect of transforming growth factor type beta 1 (TGF-beta 1) on mononuclear phagocytes (macrophages), cells which play an important role in the inflammatory response resulting from tissue wounding, was investigated. We found that fibronectin production by murine inflammatory macrophages is significantly enhanced by highly purified human TGF-beta 1 in a time- and dose-dependent manner. Specifically, 2 pM TGF-beta 1 was sufficient to cause significant elevation of fibronectin levels, which peaked between 24 and 48 hr of incubation. Both TGF-beta 1-induced and basal levels of fibronectin were completely abolished by cycloheximide, suggesting that protein synthesis was required. Furthermore, fibronectin mRNA levels were significantly enhanced in TGF-beta 1-treated macrophages. The inductive capacity of TGF-beta 1 appeared specific since other agents such as phorbol myristate acetate and endotoxin failed to induce fibronectin production. Since macrophages have been recently shown to secrete an inactive form of TGF-beta 1, the ability of this precursor molecule to induce fibronectin production was tested. It was found that partially purified human platelet latent TGF-beta 1 could not induce fibronectin synthesis, whereas acid treatment of the same preparation which releases mature TGF-beta 1 enhanced fibronectin production. Taken together, results presented here suggest that inflammatory macrophages can directly contribute to the formation of extracellular matrix upon interaction with TGF-beta 1 and that these cells lack the ability to augment fibronectin production in response to a platelet-derived latent form of TGF-beta 1.     

Expression of transforming growth factor beta (TGF-b1) by human preterm lung inflammatory cells

Using a previously published model of human BPD this study examines whether preterm lung inflammatory cells produce transforming growth factor beta 1 (TGF-beta1), a cytokine pivotal in pathogenesis of bronchopulmonary dysplasia (BPD), and whether TGF-beta1 expression is regulated by inflammation. Lung inflammatory cells (neutrophils and macrophages) recovered in the broncho-alveolar (BAL) fluid of premature infants intubated for respiratory distress after birth expressed TGF-b1 mRNA and protein. Total and bioactive TGF-beta1 were abundantly found in the BAL fluid of the same infants. In cell culture stimulation by lipopolysaccharide (LPS) did not result in any further expression of total or bioactive TGF-beta1 by neonatal lung inflammatory cells over constitutive concentrations. In conclusion, lung inflammatory cells from premature infants are a source of TGF-beta1 but LPS does not regulate TGF-b1 production in these cells.     

Cripto binds transforming growth factor beta (TGF-beta) and inhibits TGF-beta signaling

Cripto is a developmental oncoprotein and a member of the epidermal growth factor-Cripto, FRL-1, Cryptic family of extracellular signaling molecules. In addition to having essential functions during embryogenesis, Cripto is highly expressed in tumors and promotes tumorigenesis. During development, Cripto acts as an obligate coreceptor for transforming growth factor beta (TGF-beta) ligands, including nodals, growth and differentiation factor 1 (GDF1), and GDF3. As an oncogene, Cripto is thought to promote tumor growth via mechanisms including activation of mitogenic signaling pathways and antagonism of activin signaling. Here, we provide evidence supporting a novel mechanism in which Cripto inhibits the tumor suppressor function of TGF-beta. Cripto bound TGF-beta and reduced the association of TGF-beta with its type I receptor, TbetaRI. Consistent with its ability to block receptor assembly, Cripto suppressed TGF-beta signaling in multiple cell types and diminished the cytostatic effects of TGF-beta in mammary epithelial cells. Furthermore, targeted disruption of Cripto expression by use of small inhibitory RNA enhanced TGF-beta signaling, indicating that endogenous Cripto plays a role in restraining TGF-beta responses.     

Nicotine regulates basic fibroblastic growth factor and transforming growth factor beta1 production in endothelial cells

Nicotine, a constituent of cigarette smoking, may induce atherosclerosis through the production of growth factors. The pattern of bFGF and TGF beta1 production and release by bovine aortic endothelial cells (EC) stimulated with nicotine (from 6 x 10(-4) to 6 x 10(-8) M) was studied. EC viability and count were assessed. The presence of bFGF and TGF beta1 in serum-free conditioned media was determined by the inhibition antibody-binding assay and Western blot analysis. Mitogenic activity of nicotine on EC was also determined. Polymerase chain reaction (PCR) was used to study the expression of bFGF and TGF beta1. The bFGF release after nicotine stimulation was greater than controls, whereas TGF beta1 release was lower. At a nicotine concentration of 6 x 10(-6) M we noted the greatest mitogenic activity. The addition of monoclonal antibody anti-bFGF decreased the tritiated thymidine uptake of EC exposed to nicotine but the addition of monoclonal antibody anti-TGF beta1 had no significant effect. bFGF mRNA expression was significantly higher in EC exposed to nicotine than in controls, whereas TGF beta1 mRNA expression was not modified. From these data we concluded that nicotine regulates bFGF production and release and TGF beta1 release and may have a key role in the development and progression of atherosclerosis.     

Protective role of transforming growth factor beta (TGF beta) in tumor-induced degradation of basement membranes

Human fibrosarcoma cells derived from a patient with multiple metastases extensively degrade artificial basement membranes (BM) and secrete interstitial type of collagenase, a proteolytic enzyme responsible for degradation of type I collagen. Exposure of invasive cell line to TGF beta abrogates destruction of BM.TGF beta reduces collagenase activity and stimulates specific metalloproteinase inhibitor (TIMP) in invasive tumor cells. We preassume that TGF beta could play a protective role in tumor invasion.