Transforming growth factor-beta1, interleukin-10 and interferon-gamma cytokine polymorphisms in patients with hereditary, familial and sporadic chronic pancreatitis.

BACKGROUND: The genetic influence is undefined in about 40% of patients with hereditary and familial pancreatitis and in the majority of patients with sporadic chronic pancreatitis. The pathophysiological mechanisms underlying the progression from acute to chronic pancreatitis have not been clarified. Cytokines participate in the immunological progression of pancreatic inflammation and may play an important role in the development of pancreatic fibrosis. AIMS: We determined whether functional polymorphisms in the transforming growth factor-beta1 gene at positions -509, +869 (codon 10) and +915 (codon 25), in the interleukin-10 gene at position -1082, and in the intron 1 of the interferon-gamma gene at position +874 are associated with hereditary, familial or sporadic pancreatitis. METHODS: We investigated 78 patients with hereditary and familial pancreatitis and 62 patients with sporadic pancreatitis that were tested negative for cationic trypsinogen gene mutations, and 73 controls. Mutational analysis was performed by direct DNA sequencing or by amplification refractory mutational system polymerase chain reaction. We used the age at onset as marker of disease severity. RESULTS: The genotype frequencies were similar between patients and controls for all investigated cytokine polymorphisms (p > 0.05). We did not find an association between the different genotypes and the age at onset of the disease, and we did not detect different genotype distributions in patients with morphological alterations on pancreatic imaging after a disease duration of up to 5 years. CONCLUSION: These genetic variants do not play a dominant role in hereditary, familial or sporadic chronic pancreatitis.     

Expression of transforming growth factor-beta but not tumor necrosis factor-alpha, interferon-gamma, and interleukin-4 in granulomatous lung lesions in tuberculosis.

The expression of transforming growth factor (TGF-beta 1), tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma) and interleukin-4 (IL-4) were assessed in lung tissues from patients with tuberculosis. Vimentin, a constitutively expressed cellular protein, was present in 12 of 19 tissue sections indicating adequate preservation of tissue proteins in these cases. Immunohistochemical studies for cytokines were done in the vimentin positive sections only. TGF-beta 1 was localized to mononuclear phagocytes of tuberculous lung lesions in 4 of 12 tuberculosis patients. TNF-alpha, IFN-gamma, and IL-4 were absent in sections from all tuberculosis patients. The failure to detect the latter cytokines may indicate that these molecules may not be expressed at the site of disease, or are not a feature of the late stages of tuberculous granulomas. TGF beta-1, although not universally expressed, may be involved in the development and/or consequences of tuberculous granuloma formation. These data substantiate further the role of TGF-beta 1 in the immunopathology of tuberculosis.     

Paracrine up-regulation of monocyte cyclooxygenase-2 by platelets: role of transforming growth factor-beta1

OBJECTIVE: To examine the role of platelets and platelet-derived products on cyclooxygenase-2 (Cox-2) induction in adherent monocytes and to address the signaling pathways involved. METHODS: Platelets and monocytes were obtained from peripheral blood of healthy donors. Adherent monocytes were co-cultured with autologous platelets or platelet releasates or exposed to mediators contained in platelet alpha-granules (either from platelet source or recombinant) for 4-24 h. Cox-2 protein and mRNA were determined by Western and RT-PCR analysis, respectively. Thromboxane B2 (TxB2) and prostaglandin E2 (PGE2) synthesis as index of Cox-2 activity, and levels of transforming growth factor-beta1 (TGF-beta1) in platelet releasates were measured by enzyme immunoassay (EIA). RESULTS: Activated platelets induce rapid and transient Cox-2 de novo synthesis in adherent monocytes. The effect is dependent upon the platelet number but not upon cell-cell contact. Platelet-induced Cox-2 was not affected by prevention of platelet TxA2 synthesis or microparticle formation but was blunted by inhibition of platelet alpha-granule secretion. TGF-beta1, either platelet-derived or recombinant (rTGF-beta1), induced Cox-2 expression and activity in adherent monocytes at concentrations within the range of those detected in releasates from activated platelets; this effect was not shared by recombinant platelet-derived growth factor (rPDGFBB). The time course of Cox-2 induction by TGF-beta1 in monocytes was identical to that observed with platelet releasates. Moreover, TGF-beta1 receptor blockade completely abolished platelet-induced Cox-2 expression. p38 MAPK activation represents a common transduction pathway through which activated platelets and rTGF-beta1 induce Cox-2 in monocytes. CONCLUSION: These findings suggest that TGF-beta1 released by activated platelets has a pivotal role in Cox-2 induction in monocytes and further supports the key role of platelets in the inflammatory and reparative responses.     

Reduced interleukin-12 and transforming growth factor-beta1 in severe childhood malaria: relationship of cytokine balance with disease severity

Interleukin (IL)-12 and transforming growth factor (TGF)-beta1 regulate the balance between pro- and anti-inflammatory cytokines in animal models of malaria. Since the cytokine balance may be an important determinant of whether a protective or a pathogenic immune response develops, plasma cytokine ratios were examined in Gabonese children with various degrees of malarial severity. Severe disease was characterized by high-density parasitemia and severe anemia. IL-12 and TGF-beta1 were significantly lower, whereas tumor necrosis factor (TNF)-alpha and IL-10 were significantly higher in children with severe malaria. The ratios of TGF-beta1/IL-12 and IL-10/IL-12 were significantly higher in the severe, compared with the mild, malaria group. In contrast, ratios of TGF-beta1/TNF-alpha and IL-10/TNF-alpha were significantly lower in the severe malaria group. These results suggest that the inflammatory cascade in severe malaria is characterized by suppression of the protective effects of TGF-beta1 and IL-12, and that overproduction of TNF-alpha may promote deleterious effects, such as severe anemia.     

Dose-dependent cross-talk between the transforming growth factor-beta and interleukin-1 signaling pathways

Some tumor cell lines secrete high concentrations of TGFbeta or IL-1. Similarly high concentrations of each of these cytokines cross-activate the other pathway: TGFbeta activates NFkappaB, and IL-1beta activates Smads. The IL-1 signaling components IRAK, MyD88, TRAF6, and TAK1 are all required for cross-activation of NFkappaB by TGFbeta. Knockdown experiments revealed that both TGFbeta receptor subunits are required for IL-1beta to activate Smads, and the IL-1 receptor is required for TGFbeta to activate NFkappaB. Coimmunoprecipitations showed that either TGFbeta or IL-1beta stimulate ligand-dependent association of all three receptor subunits. Furthermore, cross-talk between the TGFbeta and IL-1 signaling pathways leads to dose-dependent cross-control of gene expression. These interactions provide new insight into biological responses to IL-1 and TGFbeta in the proximity of tumors that secrete high concentrations of these factors and probably also at sites of inflammation, where the local concentrations of these cytokines are likely to be high.     

Effect of tumor necrosis factor-alpha, interferon-gamma, and transforming growth factor-beta on adipogenesis and expression of thyrotropin receptor in human orbital preadipocyte fibroblasts

Graves' ophthalmopathy (GO) is an orbital autoimmune disease that is closely associated with Graves' hyperthyroidism. Examination of retroorbital tissues in GO reveals an accumulation of glycosaminoglycans, increased fat volume, lymphocytic infiltration, and the presence of several inflammatory cytokines. A subpopulation of human orbital fibroblasts can be differentiated in vitro into cells with the morphologic features of adipocytes. We demonstrated recently that these differentiated cultures show increased expression of functional TSH receptor (TSHr). To determine whether the presence of inflammatory cytokines might impact adipogenesis or TSHr expression in these cultures, we treated orbital fibroblasts from normal individuals or GO patients with tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma), or transforming growth factor-beta. We found that each of these cytokines inhibits TSH-dependent cAMP production and TSHr gene expression, and that TNF-alpha and IFN-gamma also inhibit morphological adipocyte differentiation. When cytokines were added after differentiation, the inhibition was less pronounced. Our results suggest that TNF-alpha, IFN-gamma, and transforming growth factor-beta may act within the orbit in GO to modulate expression of the putative orbital autoantigen, TSHr. In addition, the former two cytokines may play a role in determining the extent to which the volume of the orbital adipose tissue increases in this condition.     

Cytokine-mediated down-regulation of B cell activity in SLE: effects of interleukin-2 and transforming growth factor-beta

We have recently reported that transforming growth factor-beta (TGF-beta) co-stimulates interleukin-2 (IL-2) activated CD8+ T cells to down-regulate antibody production. In SLE, lymphocyte production of both IL-2 and TGF-beta is decreased. Here we report that a brief treatment of PBMC from SLE patients with IL-2 and TGF-beta can result in marked inhibition of spontaneous polyclonal IgG and autoantibody production. Peripheral blood mononuclear cells (PBMC) from 12 patients with active SLE were exposed to IL-2 with or without TGF-beta for three days, washed and cultured for seven more days. The mean decrease in IgG secretion was 79%. The strongest inhibitory effect was observed in cases with the most marked B cell hyperactivity. Spontaneous production of anti-nucleoprotein (NP) antibodies was observed in four cases and cytokine treatment of PBMC decreased autoantibody production by 50-96%. IL-2 inhibited Ig production by either TGF-beta-dependent or independent mechanisms in individual patients. In a study of anti-CD2 stimulated IgG production in a patient with active SLE, we documented that IL-2 and TGF-beta reversed the enhancing effects of CD8+ T cells on IgG production and induced suppressive activity instead. These results raise the possibility that cytokine-mediated down-regulation of B cell hyperactivity in SLE may have therapeutic potential.     

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。     

Comparing transforming growth factor-beta2, talc and bleomycin as pleurodesing agents in sheep

BACKGROUND: Transforming growth factor (TGF)-beta2 can produce effective pleurodesis in animals, but its efficacy has not been compared with commonly used pleurodesing agents in sheep, which have a thick pleura resembling that of humans. The acute physiological effects and the level of systemic TGF-beta absorption after its intrapleural administration have not been studied. The aims of the present study were to compare: (i) the effectiveness of TGF-beta2, talc and bleomycin in producing pleurodesis in sheep; (ii) the acute side-effects and systemic TGF-beta levels following the intrapleural administration of these agents; and (iii) histological changes after intrapleural injections of these agents. METHODOLOGY: Twelve sheep were divided into three groups and were given a single intrapleural dose of TGF-beta2 (0.25 microg/kg), talc slurry (5 g) or bleomycin (60 IU) via a chest tube. Saline or buffer was injected into the contralateral side, which served as the control. Arterial blood gases and respiratory and heart rates were monitored for the first 24 h. Plasma levels of TGF-beta1 and TGF-beta2 were measured. Pleurodesis was graded macroscopically from 1 (none) to 8 (symphysis > 50% of hemithorax) at day 14. RESULTS: At day 14, the pleurodesis score of the TGF-beta2 group (7.7+/-0.6) was similar to that of the talc (7.0+/-1.7) group and significantly higher than that of the bleomycin group (3.3+/-2.3; P < 0.05). No significant differences were seen in arterial blood gas analysis, vital signs and plasma TGF-beta1 and TGF-beta2 concentrations among the three groups. CONCLUSIONS: Transforming growth factor-beta2 was as effective as talc and more so than bleomycin in inducing pleurodesis in sheep. Intrapleural administration of TGF-beta2 appeared safe. No acute changes in gaseous exchange or macroscopic abnormalities were seen following intrapleural TGF-beta2. Importantly, there was no evidence of an increase in systemic TGF-beta levels following its intrapleural administration.     

Gap junction communication mediates transforming growth factor-beta activation and endothelial-induced mural cell differentiation

During blood vessel assembly, endothelial cells recruit mesenchymal progenitors and induce their differentiation into mural cells via contact-dependent transforming growth factor-beta (TGF-beta) activation. We investigated whether gap junction channels are formed between endothelial cells and recruited mesenchymal progenitors and whether intercellular communication is necessary for endothelial-induced mural cell differentiation. Mesenchymal progenitors from Cx43-/- murine embryos and Cx43+/+ littermates were cocultured with prelabeled endothelial cells. Intracellular dye injection and dual whole-cell voltage clamp revealed that endothelial cells formed gap junction channels with Cx43+/+ but not Cx43-/- progenitors. In coculture with endothelial cells, Cx43-/- progenitors did not undergo mural cell differentiation as did Cx43+/+ cells. Stable reexpression of Cx43 in Cx43-/- cells (reCx43) restored their ability to form gap junctions with endothelial cells and undergo endothelial-induced mural cell differentiation. Cocultures of endothelial cells and either Cx43+/+ or reCx43 mesenchymal cells produced activated TGF-beta; endothelial-Cx43-/- cocultures did not. However, Cx43-/- cells did produce latent TGF-beta and undergo mural cell differentiation in response to exogenous TGF-beta1. These studies indicate that gap junction communication between endothelial and mesenchymal cells mediates TGF-beta activation and subsequent mural cell differentiation.     

Glucocorticoid regulation of transforming growth factor-beta activation in urogenital sinus mesenchymal cells.

The transforming growth factors-beta (TGF-beta s) regulate many aspects of cell proliferation and differentiation. The TGF-beta isoforms are produced by most cell types in the biologically inactive, latent form. The physiological relevance of latent TGF-beta and the regulation of activation to the biologically active form are not well understood. Although expression of TGF-beta messenger RNA is regulated by the steroid hormone family, the mechanisms of hormonal regulation of TGF-beta activation have not been well studied. Fetal rat urogenital sinus organ cultures and derived mesenchymal cell lines (U4F, U4F1) have been established in order to analyze the expression of growth and differentiation regulatory factors which may function in mesenchymal induction of epithelial differentiation. The U4F1 cell line in chemically defined medium upon supplementation with dexamethasone (10 nM-1.4 microM), produced an activity which was growth inhibitory to PC-3 prostatic carcinoma epithelial cells. Analysis of physicochemical properties and purification of activity demonstrated a 25-kDa protein was responsible for activity. The activity cross-reacted to antisera specific for TGF-beta 1, beta 2 and for TGF-beta 2 exclusively, but not with antisera to rat interferon (alpha-beta) or rat interleukin 6. Acid treatment of control (unsupplemented) conditioned medium and cultures supplemented with other steroid hormones produced identical levels of activated TGF-beta as nonacid-treated conditioned medium from dexamethasone supplemented cultures which did not increase levels of activity upon acid activation. Activity from the acid-treated control conditioned medium was neutralized by TGF-beta antibodies. These data suggest latent TGF-beta is produced constitutively by U4F1 mesenchymal cultures in steroid unsupplemented medium and these cultures are induced by dexamethasone to activate identical levels of TGF-beta. These observations may be relevant to understanding diverse aspects of glucocorticoid regulation of tissue function and suggests that TGF-beta may be relevant to paracrine and autocrine growth regulation in the developing urogenital sinus.     

Inhibitory effects of the bone-derived growth factors osteoinductive factor and transforming growth factor-beta on isolated osteoclasts.

Demineralized bone matrix contains a number of growth factors for osteoblast-like cells. Two of these, the novel glycoprotein osteoinductive factor (OIF) and transforming growth factor-beta (TGF beta), act together to cause ectopic bone formation in vivo. Since OIF, like TGF beta, is likely released from bone when the matrix is resorbed, we examined the effects of homogeneous OIF and TGF beta on osteoclast function. Osteoclast function was tested in isolated avian osteoclasts and was measured in terms of tartrate-resistant acid phosphatase (TRAP) activity, oxygen-derived free radical production, and formation of characteristic resorption lacunae on slices of sperm whale dentine. OIF (50-100 ng/ml) inhibited the capacity of these osteoclasts to form lacunae whether assessed by the number of excavations per slice or by the total area resorbed. OIF (10-100 ng/ml) or TGF beta (10-20 ng/ml) caused a decrease in TRAP activity as well as a reduction in oxygen-derived free radical generation detected by nitroblue tetrazolium staining. TGF beta had no effect on the resorption capacity of isolated osteoclasts in concentrations that inhibited TRAP activity and nitroblue tetrazolium staining. These results suggest that growth regulatory factors, such as OIF and TGF beta, released during the resorption of bone may be endogenous inhibitors of continued osteoclastic activity. This cessation of osteoclast activity may be an essential preliminary step to the new bone formation that occurs at resorption sites during bone remodeling.     

Tranilast prevents activation of transforming growth factor-beta system,leukocyte accumulation,and neointimal growth in porcine coronary arteries after stenting

N(3,4-dimethoxycinnamoyl) anthranilic acid (tranilast) prevents the synchronous upregulation of isoforms and receptors of the transforming growth factor (TGF)-beta system after arterial injury and reduces restenosis after human coronary angioplasty. However, the effects of tranilast and the importance of the TGF-beta system in stent restenosis, in which inward remodeling is unimportant but inflammatory cell stimulation of neointima formation is exaggerated, are uncertain. Boston minipigs, treated with tranilast or vehicle, were subjected to endoluminal stenting, and the expression of TGF-beta1 and TGF-beta3, the expression of their signaling receptors ALK-5 and TbetaR-II, leukocyte numbers around the stent struts, and neointima development were assessed over 28 days. Stenting greatly increased early (5-day) mRNA expression of the 2 TGF-beta isoforms and their receptors. Immunohistochemical localization later showed that their concentrations were greatest in regions adjacent to stent struts, where leukocytes and collagen deposition were prevalent. Tranilast suppressed these elevations in TGF-beta mRNAs and reduced their immunoreactive peptides detectable around stent struts. The accumulation of leukocytes and deposition of collagen in these regions was also greatly inhibited by tranilast. These effects were associated with a 48% reduction in maximal neointimal cross-sectional area and 43% reduction in mean neointimal cross-sectional area at 28 days (P<0.05). We conclude that tranilast suppresses neointima development after stenting, effects that can be at least partly attributed to its ability to attenuate the induction of the TGF-beta system and leukocyte accumulation around stent struts.     

Association between transforming growth factor-beta and hypertension

Discordant findings are reported on the left ventricular transforming growth factor-beta(1) (TGF-beta(1)) mRNA levels in various rat models. Left ventricular TGF-beta(1) mRNA levels did not differ between spontaneously hypertensive rats (SHR) and normal rats, between deoxycorticosterone (DOCA)-salt and sham-operated hypertensive rats, but were increased in stroke-prone spontaneously hypertensive rats (SHRSP) and in post-myocardial infarction (MI) rats. Renal cortical TGF-beta(1) mRNA levels were, however, higher in DOCA-salt hypertensive rats. Angiotensin II subtype 1 receptor antagonism (AT(1)R) and angiotensin converting enzyme inhibition (ACEI) decreased left ventricular and vascular smooth muscle TGF-beta(1) mRNA levels in SHR and renal TGF-beta(1) mRNA in DOCA-salt hypertensive rats and in SHRSP. In post-MI rats ventricular TGF-beta(1) mRNA decreased by AT(1)R antagonism. In essential hypertensive patients, TGF-beta(1) protein as well as TGF-beta(1) mRNA levels are hyperexpressed. The TGF-beta(1) overproduction in hypertension can be attributed to various factors such as elevated angiotensin II, increased systemic blood pressure (BP) per se, increased fluid shear stress and a differential expression of TGF-beta(1) linked to DNA polymorphism in the promoter. The Arg(25) polymorphism in the TGF-beta(1) gene is associated with higher BP. A higher plasma TGF-beta(1) concentration is found in hypertensive patients with microalbuminuria and left ventricle hypertrophy. In these patients, AT(1)R antagonism and ACEI reduced these plasma TGF-beta(1) levels significantly.