TGF-beta1 Gene Expression Research Articles

Precocious activation of genes of the renin-angiotensin system and the fibrogenic cascade in IgA glomerulonephritis

The renin-angiotensin system (RAS) seems to play a pivotal role in progression of immunoglobulin A (IgA) nephropathy (IgAN). Accordingly, in patients with IgAN a relationship between the RAS and the fibrogenic cascade triggered by transforming growth factor-beta1 (TGF-beta1) should be observed. This study was carried out to obtain deeper insight into the regulation of RAS and the interaction with TGF-beta1 in the diseased kidney. Twenty renal biopsies from IgAN patients and five from renal cancer patients (controls) were analyzed in both microdissected glomerular and tubulointerstitial compartments by reverse transcription-polymerase chain reaction (RT-PCR). All patients had normal renal function. The expression of the following genes was determined: angiotensinogen (Agtg), renin, angiotensin-converting enzyme (ACE), angiotensin II (Ang II) type 1 and type II (AT1 and AT2 receptors), TGF-beta1, collagen IV (Coll IV), alpha-smooth muscle actin (alpha-SMA). Quantitative data were confirmed for TGF-beta1 and ACE genes by real-time PCR. Results. RAS genes were overexpressed in IgAN patients vs. control subjects. There was no difference between glomerular and tubulointerstitial RAS gene expression levels. On the contrary, the overactivation of fibrogenic cascade genes (TGF-beta1, Coll IV, alpha-SMA) in the tubulointerstitium was observed (TGF-beta1, glomerular 0.14 +/- 0.10 SD; tubulointerstial 0.34 +/- 0.20; P = 0.000) (alpha-SMA, glomerular 0.08 +/- 0.07; tubulointerstitial 0.35 +/- 0.19; P = 0.000) (Coll IV, glomerular 0.12 +/- 0.11; tubulointerstitial 0.22 +/- 0.10; P = 0.03). This fibrogenic cascade seems to be triggered by RAS as indicated by statistically significant correlations between the expression of their respective genes. A direct relationship between the putative Ang II activity and the expression of AT receptor genes was found in the tubulointerstitium, whereas in the glomeruli this relationship was negative. In the interstitium, statistically significant positive relationships emerged between interstitial infiltrates and the gene expression of Agtg, AT1 receptor, Coll IV, and TGF-beta1. This study demonstrates that a tight regulation of the intrarenal RAS exists in IgAN and that it follows the general rules disclosed in animal models. Moreover, the RAS seems to be activated early in the diseased kidney and it appears that such activation drives inflammation and a parallel stimulation of the TGF-beta fibrogenic loop, particularly at the tubulointerstitial level.

Distinct phases of coordinated early and late gene expression in growth plate chondrocytes in relationship to cell proliferation, matrix assembly, remodeling, and cell differentiation.

Although much has been learned about growth plate development and chondrocyte gene expression during cellular maturation and matrix remodeling in the mouse, there has been a limited study of the interrelationships of gene expression between proteinases, growth factors, and other regulatory molecules in the mouse and in other species. Here we use RT-PCR of sequential transverse sections to examine the expression profiles of genes involved in chondrocyte growth, differentiation, matrix assembly, remodeling, and mineralization in the bovine proximal tibial growth plate. Specifically, we studied the expression of genes encoding COL2A1 and COL10A1, the latter a marker of cellular hypertrophy, the matrix metalloproteinases (MMP), MMP-13 and MMP-9, as well as the transcriptional factors, Sox9 and Cbfa1, the growth factors basic fibroblast growth factor (bFGF), parathyroid hormone-related peptide (PTHrP), transforming growth factor (TGF)beta1, and beta2, Indian hedgehog (Ihh), and the matrix protein osteocalcin. These were analyzed in relationship to cell division defined by cyclin B2 expression. Two peaks of gene expression activity were observed. One was transient, limited, and located immediately before and at the onset of cyclin B2 expression in the early proliferative zone. The other was generally much more pronounced and was located in the early hypertrophic zone. The upregulation of expression of COL2A1, its transcriptional activator Sox9, osteocalcin, MMP-13, and TGFbeta2 was observed immediately before and at the onset of cyclin B2 expression and also in the hypertrophic zones. The upregulation of COL10A1, Cbfa1, MMP-9, TGFbeta-1, and Ihh gene expression was associated exclusively with the terminal differentiation of chondrocytes at the time of mineral formation in the extracellular matrix. In contrast, bFGF and PTHrP expression was observed in association with the onset of cyclin B2 expression and hypertrophy. This initial cluster of gene expression associated predominantly with matrix assembly and onset of cell proliferation is therefore characterized by expression of regulatory molecules distinct from those involved at hypertrophy. Together these results identify separate phases of coordinated gene expression associated with the development of the physis in endochondral bone formation.

Advanced glycation end products inhibit de novo protein synthesis and induce TGF-β overexpression in proximal tubular cells

We have shown previously that OPB-9195, a novel inhibitor of advanced glycation end products (AGE), significantly prevented renal tubular injury and tubulointerstitial fibrosis in spontaneous diabetic rats. However, the molecular mechanisms underlying this have not been fully elucidated. Three immunochemically distinct AGE were prepared by incubating bovine serum albumin (BSA) with glucose, glyceraldehyde, or methylglyoxal. Then, the effects of AGE on human proximal tubular epithelial cells were examined. The intracellular formation of reactive oxygen species (ROS) was detected using the fluorescent probe CM-H2DCFDA. DNA synthesis was evaluated by thymidine uptake, and de novo protein synthesis was determined by [3H]leucine incorporation. Prostaglandin E2 (PGE2) and transforming growth factor-beta (TGF-beta) released into media were quantitatively analyzed in an enzyme-linked immunosorbent assay. TGF-beta gene expression was analyzed by quantitative reverse transcription-polymerase chain reaction (RT-PCR). When these AGE-BSA were administered to tubular cells, each of them increased generation of intracellular ROS. All of the AGE-BSA, but not non-glycated BSA, were found to induce statistically significant decreases in de novo protein synthesis and PGE2 secretion by tubular cells. Furthermore, AGE-BSA up-regulated the levels of mRNAs for TGF-beta in tubular cells. The structural epitope designated glucose-derived AGE was found to have the greatest cytopathic effects on tubular cells. These AGE-induced inhibition of protein synthesis and PGE2 secretion as well as the up-regulation of TGF-beta mRNA were found to be completely prevented by N-acetylcysteine. Furthermore, H2O2 was shown to inhibit protein synthesis and PGE2 secretion by proximal tubular cells in a dose-dependent manner. The results suggest that AGE inhibits de novo protein synthesis and stimulates TGF-beta mRNA expression in proximal tubular epithelial cells through overgeneration of intracellular ROS. Thus, AGE are involved in the pathogenesis of tubular injury in diabetic nephropathy.

Intradermal injection of transforming growth factor-beta1 gene enhances wound healing in genetically diabetic mice.

To evaluate the biologic effect of direct cutaneous TGF-beta1 gene delivery on impaired wound healing models using genetically diabetic mice. Diabetic mice (C57BKS.Cg-m +/+ Leprdb female mice) with 1 cm x 1 cm excisional wounds were intradermally injected with 60 microg of plasmid DNA encoding TGF-beta1 gene. The wound closure was measured up to 14 days postwounding. At days 7 and 14 postwounding, sections of skin were taken for hematoxylin and eosin and Masson's trichome staining to examine the morphology and collagen deposition. The cell proliferation and TGF-beta1 gene expression were studied using immunohistochemical stainings for 5-bromo-2-deoxyuridine and for TGF-beta1. A higher cell proliferation rate and a denser and more organized new extracellular matrix were observed in the treated wound site. Complete wound closure was detected as early as 7 days for TGF-beta1-treated group in comparison with 11-14 days for the untreated, control plasmid DNA- and PBS-treated groups. A single intradermal injection of TGF-beta1 plasmid DNA was sufficient to enhance wound healing. This approach represents a new strategy that may be applied to the treatment of excisional wounds in human diabetic patients.

Local expression of cytokine genes in uterine adnexa and endometrium of women with pyoinflammatory adnexal diseases.

Changes in the local expression of IL-1beta, IL-2, IL-4, IL-6, IL-8, IL-10, IL-12, IL-15, IL-18, TNF-alpha, IFN-gamma- and TGF-beta(2) genes in the uterine adnexa and endometrium were studied in women with pyoinflammatory adnexal diseases. Examination of tissue specimens from the uterine adnexa involved in inflammation revealed a direct correlation in the levels of mRNA production between IL-6 and IL-10 (r=0.93, p<0.1), IL-6 and IL-4 (r=0.96, p<0.01), IL-10 and IL-4 (r=0.91, p<0.01), IL-12 and IFN-gamma (r=0.98, p<0.01). Expression of IL-4 gene increased 5.1-fold (p=0.001), IL-6 2-fold (p=0.007), IL-8 90.2-fold (p=0.009), IL-10 2.9-fold (p=0.008), IL-12 2.3-fold (p=0.3), and TGF-beta(2) gene 10.3-fold (p=0.1). In the endometrium of women with pyoinflammatory adnexal diseases only IL-10 gene expression increased (15.6-fold, p=0.007).

Titanium surface topography alters cell shape and modulates bone morphogenetic protein 2 expression in the J774A.1 macrophage cell line.

Macrophage cytokine expression significantly affects wound healing. Macrophage secretion of transforming growth factor beta 1 (TGFbeta1) and bone morphogenetic proteins (BMP) may affect osteogenesis at endosseous implant surfaces. The aim of this investigation was to determine the effect of commercially pure titanium (cpTi) substrate topography on adherent macrophage osteogenic and osteoinductive cytokine expression. J774A.1 murine macrophage cell adhesion was examined by scanning electron microscopy, 0-72 h following plating onto polished, machined, and grit-blasted cpTi surfaces. TGFbeta1 and BMP-2 gene expression by adherent macrophages was determined by the reverse transcription polymerase chain reaction. Macrophage adhesion increased with time on all surfaces and spreading increased with increasing surface roughness (polished < machined < grit-blasted). BMP-2 expression was not evident for cells adherent to polished cpTi at 24 h. In contrast, BMP-2 expression occurred at 24 h in cells adherent to machined and grit-blasted cpTi. BMP-2 expression was evident on all surfaces at 72 h and was greatest in grit-blasted titanium adherent cells. Increasing concentrations of cytochalasin B (0-50 microM) inhibited macrophage spreading and reduced BMP-2 mRNA expression, suggesting a relationship between cell shape and BMP-2 expression. This was further characterized using anti-beta1 and anti-beta3 integrin antibodies. The anti-beta1 integrin antibodies inhibited adherent macrophage BMP-2 mRNA expression. Anti-beta3 integrin antibody treatment only modestly reduced BMP-2 mRNA expression. Endosseous implant surface topography induced changes in macrophage shape that were associated with changes in BMP-2 expression in J774A.1 mouse macrophage cell line. This first demonstration of BMP-2 expression by cpTi adherent macrophages suggests that the macrophage may contribute surface-specific osteoinductive signals during bone formation at implanted alloplastic surfaces.

Establishment of a novel collagenase perfusion method to isolate rat pancreatic stellate cells and investigation of their gene expression of TGF-beta1, type I collagen, and CTGF in primary culture or freshly isolated cells.

In studies of the pathogenesis of pancreatic fibrosis, pancreatic stellate cells (PSCs) have recently gained attention. In the present study, we established a new collagenase perfusion method through thoracic aorta cannulation to isolate PSCs, and we studied gene expression of TGF-beta1, type I collagen, and connective tissue growth factor using primary cultured PSCs. Our method facilitated PSC isolation, and by our new method, 4.3 +/- 1.2 x 10(6) PSCs were obtained from a rat. In comparing the expression of these genes with that of hepatic stellate cells (HSCs), we observed a similar pattern, although PSCs expressed type I collagen gene earlier than did HSCs. These results suggest that PSCs may play an important role in fibrosis of the pancreas, as HSCs do in liver fibrosis; in addition, PSCs may exist in a preactivated state or may be more easily activated than are HSCs. We also isolated the PSCs from a WBN/Kob rat, the spontaneous pancreatitis rat, and compared the gene expression with that from a normal rat.

Mechanisms of Chinese herb emodin and somatostatin analogs on pancreatic regeneration in acute pancreatitis in rats.

Studies have revealed that emodin is a potent agent in the management of clinical and experimental acute pancreatitis, but the molecular mechanisms by which emodin produces its biologic effects, especially on pancreatic regeneration after acute pancreatitis, remain unknown. Numerous experimental and clinical studies have shown that somatostatin analogs have favorable effects on acute pancreatitis, but their role in the management of acute pancreatitis remains controversial. To investigate mechanisms of the Chinese herb emodin and somatostatin analogs (SSa; Sandostatin) in acute pancreatitis of rats by analyzing the changes in pancreatic tissue cytokine transforming growth factor beta1 (TGFbeta1) and epidermal growth factor (EGF) gene expression, DNA synthesis, total protein content, and the relations between them. Acute pancreatitis was induced by intraperitoneal infusion of cerulein in rats. Emodin was administered intravenously and Sandostatin was administered subcutaneously at the time of induction of pancreatitis and 24, 48, and 72 hours afterward. Rats were killed at 6, 24, 48, 72, and 96 hours after the operation. The mRNA expression of TGFbeta1 and EGF were evaluated by reverse transcription polymerase chain reaction, and pancreatic tissue DNA synthesis was measured by the 3H-thymidine incorporation method in vitro. Total protein content was detected by Lowry's method. The serum amylase level was decreased significantly in the emodin-treated and Sandostatin-treated groups in comparison with the nontreated group. Pancreatic tissue DNA synthesis was significantly decreased at 72 hours after the induction of pancreatitis, and a marked increase was observed at 96 hours after treatment with emodin and Sandostatin. Within 48 hours of the induction of pancreatitis, the total protein content in pancreatic tissue declined, but there was a remarkable increase in the emodin-treated group at 96 hours and Sandostatin-treated group at 48 hours. Expression of TGFbeta1 mRNA and EGF mRNA were undetectable in normal pancreas and the nontreated group at 6 hours but was observed from 24 hours to 96 hours after the induction of pancreatitis and reached its maximum at 72 hours. TGFbeta1 mRNA could be detected 6 hours after treatment with emodin and Sandostatin, and its expression was significantly higher in the emodin-treated and Sandostatin-treated groups than in the nontreated group at 24 and 48 hours. The expression of EGF mRNA was significantly higher in the emodin-treated and Sandostatin-treated group than in the nontreated group at 48 hours. It was concluded that mechanisms of the Chinese herb emodin and somatostatin analogs in the management of acute pancreatitis in rats might be ascribed to the upregulation of TGFbeta1 and EGF gene expression, which subsequently increases DNA synthesis and protein content and thus accelerates pancreatic repair and regeneration.

Titration of non-replicating adenovirus as a vector for transducing active TGF-beta1 gene expression causing inflammation and fibrogenesis in the lungs of C57BL/6 mice.

Investigators have shown that interstitial pulmonary fibrosis (IPF) can be induced in rats by overexpressing transforming growth factor beta1 (TGF-beta1) through a replication-deficient recombinant adenovirus vector instilled into the lungs (Sime et al. 1997). We have shown that this vector induces IPF in fibrogenic-resistant tumour necrosis factor alpha-receptor knockout (TNF-alphaRKO) mice (Liu et al. 2001). The object of our studies is to understand how peptide growth factors, such as TGF-beta1, mediate interstitial lung disease (ILD). To do so, we must be able to manipulate the dose of the factor and sort out its effects on multiple other mediators in the lung parenchyma. As a step in this complex process, in the studies reported here, we have determined the concentrations of the recombinant adenovirus vector carrying the gene for porcine active TGF-beta1 (AVTGFbeta1) that have little apparent effect, cause clear induction of disease, or severe disease. The disease largely resolves by 28 days in all cases, thus providing a valuable model to understand the mechanisms of the IPF that is mediated, at least in part, by TGF-beta1. The findings here show that 10(6) plaque-forming units (pfu) of AVTGFbeta1, provide essentially a 'no-effect' dose, but even this amount of TGF-beta1 causes a significant increase in whole-lung collagen by day 28 after treatment. In contrast, 10(8) and 10(9) pfu cause severe IPF in 4 days, whereas 10(7) and 5 x 10(7) are intermediate for all parameters studied, i.e. TGF-beta protein, inflammatory cells, cell proliferation, pro-alpha 1(I) collagen gene expression and whole-lung collagen accumulation, and expression of growth factors such as TGF-beta1, TNF-alpha and PDGF-A and -B. Interestingly enough, TGF-beta1, as a potent blocker of epithelial cell proliferation, appears to suppress airway epithelial cell growth that would be expected during the inflammatory phase of IPF. Thus, this model system helps us to understand some quantitative aspects of TGF-beta1 biological activity and allows us to manipulate this potent factor as a mediator of interstitial fibrogenesis.

AT1 receptor blockade reduces cardiac calcineurin activity in hypertensive rats.

The possible role of calcineurin in the attenuation of cardiac hypertrophy and fibrosis by blockade of the angiotensin II type 1 (AT1) receptor was investigated in Dahl salt-sensitive (DS) rats. The effect of the calcineurin inhibitor FK506 was also studied. DS rats progressively developed severe hypertension when fed a diet containing 8% NaCl from 7 weeks of age. In addition, marked cardiac hypertrophy and fibrosis were apparent and the activity of calcineurin and its mRNA expression in the myocardium was increased in these animals at 12 weeks in comparison with age-matched Dahl salt-resistant rats. The abundance of angiotensin-converting enzyme (ACE) and transforming growth factor (TGF)-beta1 mRNAs was also increased in the hearts of DS rats at 12 weeks. Treatment of DS rats with a non-antihypertensive dose of the selective AT1 receptor blocker candesartan (1 mg/kg per day) or FK506 (0.1 mg/kg per day) from 7 to 12 weeks attenuated both calcineurin activity and its mRNA expression in the heart, as well as the development of cardiac hypertrophy and fibrosis, without affecting cardiac function. Treatment with candesartan, but not FK506, prevented the upregulation of ACE and TGF-beta1 gene expression. Both candesartan and FK506 prevented the load-induced induction of fetal-type cardiac genes. These results demonstrate that AT1 receptor blockade attenuates the development of cardiac hypertrophy and fibrosis as well as the activation of calcineurin, without an antihypertensive effect, in rats with salt-sensitive hypertension. Calcineurin may be downstream from TGF-beta1 in AT1 receptor-mediated angiotensin II signaling in vivo.

Crouzon's syndrome: differential in vitro secretion of bFGF, TGFbeta I isoforms and extracellular matrix macromolecules in patients with FGFR2 gene mutation.

In the Crouzon's syndrome the cranial morphogenic processes are altered due to the early fusion of cranial sutures. We analysed the phenotype of cultured fibroblasts from normal subjects and from Crouzon patients with a specific fibroblast growth factor receptor 2 mutation resulting in a Cys 342 Tyr substitution within the third immunoglobulin domain. Crouzon fibroblasts differed from normal fibroblasts in their extracellular matrix macromolecule accumulation. In Crouzon fibroblasts glycosaminoglycans and fibronectin were decreased and type I collagen increased. As transforming growth factors beta (TGF beta) and basic fibroblasts growth factor (bFGF) together regulate extracellular matrix deposition, we evaluated TGF beta(1), TGF beta(3) and bFGF production by Crouzon and normal fibroblasts. TGF beta(1), TGFb(3) and bFGF levels were lower while TGF beta(1) mRNA transcripts were higher in Crouzon cells. As the increased TGF beta(1) gene expression did not translate into a parallel increase of secreted TGF beta(1), control of TGF beta(1) secretion may be mainly post-transcriptional. Furthermore, adding bFGF increased TGF beta(1) and TGF beta(3) secretion, suggesting the drop may be due to the altered signal transduction of bFGF. These innovative data suggest the in vitro differences between normal and Crouzon fibroblasts may be due to an imbalance in TGF beta and bFGF levels which alters the microenvironment where morphogenesis takes place.

Collagen accumulation after myocardial infarction: effects of ETA receptor blockade and implications for early remodeling.

Endothelin A (ETA) receptor blockade started early after myocardial infarction (MI) promotes adverse left ventricular (LV) dilatation. We tested the hypothesis that inhibition of ETA receptors during the early phase of healing affects collagen synthesis and accumulation, and induces expansion of infarcted myocardium. Starting 3 h after coronary ligation, female Wistar rats were treated with the selective ETA receptor antagonist LU 135252 (30 mg/kg body wt/day) or placebo. A period of 7 days after MI, hemodynamic, morphometric and biochemical studies were performed. ET(A) receptor blockade enhanced infarct expansion index and decreased LV systolic function. Infarct scar of LU 135252-treated rats displayed decreased gene expression of fibrillar type I/III collagens and of transforming growth factor-beta(1) (TGF-beta(1)). Collagen content in the infarct scar and border regions was lower after ETA inhibition. In addition, Western blot analysis revealed, after ETA receptor blockade, enhanced matrix metalloproteinases MMP-13, and MMP-2 expression in the infarcted LV myocardium. These data demonstrate that endothelin stimulates collagen accumulation at the site of infarction. Decreased collagen and TGF-beta(1) gene expression, associated with enhanced infarct expansion and MMP up-regulation likely contributes to ETA receptor blockade-mediated deleterious effects on ventricular remodeling after infarction.

Quantitative gene expression of TGF-beta1, IL-10, TNF-alpha and Fas Ligand in renal cortex and medulla.

Inflammatory, fibrogenic or apoptotic processes in the kidney are regulated by intra- and intercellular mediators. Intrarenal upregulation of genes may precede structural changes by days and can be examined in extremely small amounts of tissue. With the advent of new quantitative PCR methods results of gene expression are available within few hours after kidney biopsies. In order to establish reference values for intrarenal gene expression of TGF-beta1, IL-10, TNF-alpha and Fas Ligand in renal cortex and medulla, we analysed 28 histologically normal kidney samples available after tumour nephrectomy by quantitative real-time PCR. After reverse transcription of isolated RNA, cDNA aliquots were quantified for target genes using the threshold cycle (C(t)) method normalized for the house keeping gene GAPDH. Expression of target genes was lower in cortex as compared to medulla, but the differences were only significant for IL-10 (P=0.0125). TGF-beta1 was found with the highest gene expression about five PCR-cycles (delta C(t)) after GAPDH with markedly lower results for TNF-alpha (delta C(t) approximately 9), IL-10 (approximately 12) and Fas Ligand (approximately 14). These results are the first reported reference values for human intrarenal gene expression which should facilitate interpretation of data from native or transplant kidneys in future studies.

Activated intrarenal transcription of CTL-effectors and TGF-β1 in children with focal segmental glomerulosclerosis

The pathogenesis of childhood nephrotic syndrome (NS), whether the lesion is minimal change disease (MCD) or focal segmental glomerulosclerosis (FSGS), remains elusive. Based on the presence of elevated cytokine levels in peripheral blood, a T cell-induced injury could be postulated. To test the hypothesis that infiltrating T cells actively contribute to the glomerular injury in children with NS, we studied the intrarenal transcription of various T cell-related chemokines, cytokines and cytotoxic T-lymphocyte (CTL) effector molecules in the renal biopsy tissue of 52 nephrotic children with a variety of histologic lesions. Intrarenal gene expression was studied using reverse transcription (RT)-assisted-polymerase chain reaction (PCR). Interleukin-2 (IL-2) and IL-4 transcripts were not observed in any of the specimens. IL-2 receptor alpha mRNA was detected in 24 of 40 proteinuric patients, but also in 6 of 10 patients in remission and showed no significant differences with regard to steroid response. Intrarenal gene expression of CTL mediators and transforming growth factor-beta1 (TGF-beta1) was noted particularly in patients with progressive disease leading to chronic renal failure. TGF-beta1 gene expression was noted in 23 of 29 steroid resistant (SR) children with NS not caused by lupus nephritis and in 18 of 20 FSGS patients. In contrast TGF-beta1 gene expression was detected in only 3 of 14 steroid-sensitive patients (P < 0.001). Two of these patients later developed FSGS. In patients with steroid-resistant NS, intrarenal TGF-beta1 gene expression showed a positive predictive value of 90% and a negative predictive value of 88% to identify FSGS (P < 0.0001). These results support the notion that immunologically mediated events contribute to the progressive renal damage seen in children with FSGS.

Attenuation of tubular apoptosis by blockade of the renin-angiotensin system in diabetic Ren-2 rats

Tubular atrophy is a major feature of most renal diseases and is closely associated with loss of renal function. The present study sought to investigate tubular epithelial cell apoptosis in experimental diabetic nephropathy and to explore the role of pro-apoptotic [transforming growth factor-beta (TGF-beta) and anti-apoptotic growth factors [epidermal growth factor (EGF)]. The effects of renoprotective therapy with blockade of the renin-angiotensin system (RAS) also were examined. Six-week-old female Ren-2 rats were injected with streptozotocin (STZ) and maintained diabetic for 12 weeks. Further groups of diabetic rats were treated with the angiotensin-converting enzyme (ACE) inhibitor, perindopril, or the angiotensin II type 1 (AT1) receptor antagonist, valsartan, for 12 weeks. Widespread apoptosis, identified immunohistochemically by single stranded DNA and TUNEL, was noted in the tubules of diabetic Ren-2 rats. These changes were associated with a 50% decrease in EGF expression and a twofold increase in TGF-beta1 mRNA. Treatment of diabetic Ren-2 rats with either valsartan (20 mg/kg/day) or perindopril (6 mg/kg/day) reduced apoptosis to control levels in association with supranormal levels of EGF mRNA (P < 0.01) and a reduction in TGF-beta1 gene expression (P < 0.05) to that of control rats. Tubular apoptosis is a prominent feature of diabetic Ren-2 rats that is attenuated by blockade of the RAS in association with modulation of pro- and anti-apoptotic growth factor expression.

Decorin transfection in human mesangial cells downregulates genes playing a role in the progression of fibrosis.

The proteoglycan decorin inhibits TGF-beta; therefore, it could antagonize progression of fibrotic diseases associated with activation of TGF-beta(1). The effect of decorin transfection in human mesangial cells (HMCs) on the expression of genes related to kidney fibrosis was investigated. HMCs, isolated from glomeruli of healthy portions of human kidneys removed due to carcinoma, were histochemically typed. Decorin cDNA cloned in a eukaryotic expression vector was transfected into HMCs. Gene expression of fibrogenetic cytokines and fibrotic proteins TGF-beta(1), PDGF-beta, alpha(1) collagen type IV, alpha(1) collagen type I, fibronectin, and tenascin was analyzed, by reverse transcription polymerase chain reaction (RT-PCR), 24 hr after transfection. Immunoblotting analysis of protein extracts using anti-decorin IgG, revealed a positive signal of about 52 MDa, corresponding to the molecular weight of decorin, in cultures transfected with the decorin gene. Decorin mRNA increased about 12 times in cultures transfected with the construct pCR3.1-Deco. Cells with increased decorin synthesis showed a 61% decrease of TGF-beta(1) mRNA, a 71% reduction of alpha1 collagen type IV mRNA, and a 29% reduction of fibronectin mRNA. This study is the first to investigate decorin transfection into human mesangial cells, and supports the use of the decorin gene to control the progression of glomerular and interstitial fibrosis in kidney diseases.

Quantitative analysis of transforming growth factor beta 1 mRNA in patients with alcoholic liver disease.

To investigate the expression of the transforming growth factor beta 1(TGF-beta 1) mRNA in different stages of alcoholic liver disease (ALD) and its clinical value. One hundred and seven male alcoholics were grouped by clinical findings into four groups: alcohol abusers without liver impairment (n =22), alcoholic steatosis (n =30); alcoholic hepatitis (n=31); and alcoholic cirrhosis(n=24). Using peripheral blood mononuclear cells (PBMC) as samples the gene expression of TGF-beta 1 was examined quantitatively by reverse transcription polymerase chain reaction (RT-PCR) and dot blot. There are 34 healthy subjects served as control. The expression of TGF-beta 1 from all ALD patients was significantly greater than that in controls (1.320 +/- 1.162 vs 0.808 +/- 0.276, P<0.001). The differences of the expressions were significant between the patients from each groups (alcoholic steatosis, alcoholic hepatitis and alcoholic cirrhosis) and the controls (1.168 +/- 0.852, 1.462 +/- 1.657, 1.329 +/- 0.610 vs 0.808 +/- 0.276, P<0.050). No significant differences of TGF -beta 1 mRNA expression were observed between alcohol abusers without liver impairment and controls. The expressions in patients with alcoholic hepatitis and alcoholic cirrhosis were significantly greater than that in alcohol abusers respectively (1.462 +/- 1.657, 1.329 +/- 0.610 vs 0.841 +/- 0.706, P<0.050). No significant differences of TGF-beta 1 mRNA expression were observed between alcoholic fatty liver men and alcohol abusers. TGF-beta 1 expression level can be a risk factor for alcoholic liver disease and might be related to the inflammatory activity and fibrosis of the liver in patients.

Transforming growth factor-beta1 and tumor growth factor-beta-inducible gene-H3 in nonrenal transplant cyclosporine nephropathy.

Cyclosporine nephropathy (CyAN) is a major limiting factor in the otherwise successful widespread use of cyclosporine in solid organ transplant. Transforming growth factor-beta1 (TGF-beta1) has been implicated as an important fibrogenic cytokine in the development of this disease. TGF-beta-inducible gene-H3 (beta(ig)-H3) is a TGF-beta1- induced gene product, which acts as a marker for biologically active TGF-beta1. This study reports TGF-beta1 gene expression and beta(ig)-H3 tissue distribution in non-renal allograft CyAN. Renal tissue from nine patients who had developed CyAN after successful heart or heart-lung transplantation and from four kidneys removed for tumour were analyzed for TGF-beta1 gene expression beta(ig)-H3 protein with reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry, respectively. TGF-beta1 gene expression was increased in CyAN compared to nephrectomy (P<0.0001). Beta(ig)-H3 protein expression was identified in distal convoluted tubular epithelium and parietal glomerular epithelium in CyAN, and not in nephrectomy samples. Expression of TGF-beta1 mRNA was significantly higher in renal tissue from patients not receiving angiotensin converting enzyme inhibitor (ACEI) therapy for hypertension (P<0.05). These findings support the hypothesis that TGF-beta1 is an important cytokine in the development of CyAN, independent of its role in chronic rejection in renal allografts.

Protease-activated receptor 1 and plasminogen activator inhibitor 1 expression in chronic allograft nephropathy: the role of coagulation and fibrinolysis in renal graft fibrosis.

Chronic allograft nephropathy (CAN), the major cause of renal graft failure, frequently displays extensive interstitial fibrin deposition. Little is known in regard to the cause of the altered coagulation/fibrinolysis balance and its relevance in the pathogenesis of CAN. Thrombin, present within the fibrin clots, can interact with a specific receptor, protease-activated receptor 1 (PAR-1), and modulate a variety of cell functions. On the other hand, the derangement of the fibrinolytic system may directly affect extracellular matrix (ECM) degradation. In the present study, we investigated, by in situ hybridization, PAR-1 gene expression and the mRNA levels for tissue factor and plasminogen activator inhibitor 1 (PAI-1), two key regulatory molecules of coagulation and fibrinolysis, in 16 CAN biopsies and in 10 normal human kidney grafts. The thrombin-induced transforming growth factor beta (TGF-beta) gene and protein expression in proximal tubular cells (PTC) was investigated by Northern blotting and ELISA, respectively. Fibrin deposits, absent in normal grafts, were observed in the interstitial space and arterial wall of CAN. Tissue factor gene expression was not increased either at the vascular or at the interstitial level in CAN. On the contrary, PAI-1 gene expression, barely detectable in control tissue, was strikingly increased in CAN, with a distribution resembling the pattern of fibrin deposition. Note that PAI-1 gene expression was directly correlated with the degree of interstitial fibrosis. In addition, fibrin deposits were strictly associated with a marked increase of PAR-1 gene expression in endothelial cells and PTC. The tubular expression of PAR-1 was significantly higher in Banff grade II-III than in grade I. In vitro, incubation of PTC with thrombin caused a significant up-regulation of TGF-beta gene expression, followed by an increased TGF-beta release into the supernatant. Interestingly, urine from CAN patients contained significantly higher levels of TGF-beta. Fibrin deposits in CAN may result from the increased expression of PAI-1 and the subsequent inhibition of fibrinolysis. The reduced fibrinolysis may cause, in turn, a decreased ECM turnover. Finally, thrombin, preserved in the active form within the fibrin clots, may interact with PAR-1 highly expressed on PTC and induce an up-regulation of ECM deposition in a TGF-beta-dependent manner.

Cultured rat glomerular epithelial cells show gene expression and production of transforming growth factor-beta: expression is enhanced by thrombin.

Glomerular crescents play an important role in progressive glomerular injury. The lesions consist of epithelial cells, macrophages, and deposits of fibrin and extracellular matrix. Transforming growth factor beta (TGF-beta) contributes to the modulation of cell growth and extracellular matrix synthesis. Thrombin is involved in fibrin formation in crescents. The purpose of this study was to examine whether glomerular epithelial cells (GEC) could produce TGF-beta, and if so, to clarify the role of TGF-beta in GEC proliferation. We also investigated whether thrombin could modulate the production of TGF-beta and extracellular matrix by GEC. Bioassay using the TGF-beta-dependent mink pulmonary epithelial cell line (CCL-64), immunoblot analysis, and reverse transcriptase polymerase chain reaction (RT-PCR) were used to demonstrate TGF-beta production by rat GEC. TGF-beta gene expression was examined by RT-PCR in GEC incubated with thrombin, and type IV collagen and fibronectin were quantified by enzyme immunoassay in culture supernatants of GEC incubated with thrombin or TGF-beta. TGF-beta activity was demonstrated in GEC supernatants by bioassay. Immunoblot analysis of concentrated culture supernatants using anti-TGF-beta antibody revealed a 12.5-kDa protein, which was compatible with TGF-beta. Concentrated GEC supernatants inhibited GEC proliferation as well as porcine TGF-beta. RT-PCR demonstrated TGF-beta gene expression in GEC. Thrombin (0.5-5.0 U/ml) enhanced TGF-beta mRNA expression in a dose-dependent manner. Thrombin (5.0 U/ml) and porcine TGF-beta (5.0 ng/ml) stimulated the production of type IV collagen and fibronectin by GEC. Rat GEC produce TGF-beta in vitro. Thrombin may participate in the progression of glomerulosclerosis in crescentic glomerulonephritis through the stimulation of TGF-beta production by GEC.