Transforming Growth Factor-beta1 Gene Expression Research Articles

Anti-Fibronectin Aptamer Modifies Blood Clot Pattern and Stimulates Osteogenesis: An Ex Vivo Study.

Scaffold (SCA) functionalization with aptamers (APT) provides adsorption of specific bioactive molecules on biomaterial surfaces. The aim of this study was to observe if SCA enriched with anti-fibronectin APT can favor coagulum (PhC) and osteoblasts (OSB) differentiation. 20 μg of APT was functionalized on SCA by simple adsorption. For PhC formation, SCAs were inserted into rat calvaria defects for 17 h. Following proper transportation (buffer solution PB), OSBs (UMR-106 lineage) were seeded over PhC + SCAs with and without APT. Cells and PhC morphology, PhC cell population, protein labeling and gene expression were observed in different time points. The APT induced higher alkaline phosphatase and bone sialoprotein immunolabeling in OSB. Mesenchymal stem cells, leukocytes and lymphocytes cells were detected more in the APT group than when scaffolds were not functionalized. Additionally, an enriched and dense fibrin network and different cell types were observed, with more OSB and white blood cells in PhC formed on SCA with APT. The gene expression showed higher transforming growth factor beta 1 (TGF-b1) detection in SCA with APT. The SCA functionalization with fibronectin aptamers may alter key morphological and functional features of blood clot formation, and provides a selective expression of proteins related to osteo differentiation. Additionally, aptamers increase TGF-b1 gene expression, which is highly associated with improvements in regenerative therapies.

MicroRNAs Markedly Expressed in Apical Periodontitis Cooperatively Regulate Cytokines and Growth Factors Promoting an Anti-inflammatory Response

IntroductionMicroRNAs have been shown to play a role in the pathogenesis of apical periodontitis. Upregulation of miR-10a-5p and downregulation of miR-891a-5p were previously reported in apical periodontitis samples. This study aims to perform a functional characterization of miR-10a-5p, investigating its capacity to regulate the expression of inflammatory cytokines and growth factors, as well as a possible co-regulation mechanism with miR-891a-5p in the development of apical periodontitis. MethodsmiR-10a-5p mimics/controls and miR-891a-5p inhibitors/controls were introduced to human K-562 cells in the presence or absence of lipopolysaccharide. Total RNA was extracted from cell lysates, and target genes were examined via quantitative reverse transcription-polymerase chain reaction. Cell lysates were also subjected to proteomics analysis. Furthermore, mimics of miR-10a-5p and inhibitors of miR-891a-5p were co-transfected into K-562 cells. RNA sequencing and quantitative reverse transcription-polymerase chain reaction were carried out to examine their target genes. ResultsOverexpression of miR-10a-5p led to downregulation of tumor necrosis factor-alpha and interleukin-1 beta mRNA and upregulation of transforming growth factor-beta 1 (TGFB1) mRNA expression, whereas interleukin 3 and TGF-β1 proteins were upregulated. Simultaneous overexpression of miR-10a-5p and inhibition of miR-891a-5p further increased TGFB1 mRNA transcript levels. RNA sequencing revealed that genes co-regulated by miR-10a-5p and miR-891a-5p may be involved in apical periodontitis-related pathways such as tumor necrosis factor, transient receptor potential, and vascular endothelial growth factor signaling pathways. ConclusionsmiR-10a-5p may modulate the expression of multiple inflammatory cytokines and growth factors such as tumor necrosis factor-alpha, IL-1β, interleukin 3, and TGF-β1. In addition, miR-10a-5p and miR-891a-5p cooperatively regulate TGFB1 gene expression, and the gene network of this co-regulation is integrated with many pathways in apical periodontitis.

Effects of lavender (Lavandula angustifolia) extract inclusion in diet on growth performance, innate immunity, immune-related gene expression, and stress response of common carp, Cyprinus carpio

In the present study, the effects of dietary lavender (Lavandula angustifolia) extract (LE) on growth performance and immune, antioxidant, and stress responses in common carp, Cyprinus carpio were investigated. For this, four diets containing 0, 0.5, 1.0 and 1.5% LE were offered to triplicate groups of fish (25.8 ± 1.66 g) for 70 days, and then the fish were exposed to a 3-h crowding stress. Growth performance, blood leukocyte count, plasma proteins and innate immune parameters, and head kidney cytokines’ gene expression were studied after the 70-day feeding trial (before the crowding stress). Plasma cortisol, glucose, superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA) were measured before and after the crowding stress. Results showed that dietary LE had no significant effects on the fish growth performance, blood leukocyte differential count, plasma albumin and total protein, and head kidney interferon gamma-1 gene expression. Blood leukocyte and plasma globulin, alternative complement and total immunoglobulin significantly increased in the fish fed with 1.0–1.5% LE diets compared to the fish fed with the control diet (0% LE). The plasma lysozyme activity significantly increased along with dietary LE supplemental levels. The lowest expression of interlukin-1 beta gene was related to the 1.0% LE treatment. Tumor necrosis factor-alpha gene expression significantly decreased along with increase in dietary LE levels and the lowest expression was related to the fish fed with 1.5% LE diet. The LE administration led to significant increase in interlukine-10 gene expression and the highest expression was related to the fish fed with 1.0% and 1.5% LE diets. The fish fed with 1.5% LE diet had significantly higher transforming growth factor-beta gene expression compared to the control group. Liver SOD and CAT activities showed significant increases along with dietary LE supplementation levels. After the crowding stress, hepatic SOD decreased in the control group, but not the LE-supplemented groups. Stress led to significant decrease in hepatic CAT activities in all treatments, but CAT activity increased along with the LE levels with highest activity in the fish fed with 1.5% LE. The stress led to significant increase in hepatic MDA in the treatments control and 0.5% LE, but not 1.0–1.5% LE groups. The stress led to significant increase in plasma cortisol and glucose levels in all treatments but dietary LE levels significantly decreased these parameters. Dietary LE supplementation at levels of 1.0–1.5% is recommended for common carp to suppress stress, inflammation and oxidative conditions and augment immune responses in the fish.

Influence of the Polymorphism C-509T in the TGFB1 Gene Promoter on the Response to Montelukast.

Transforming growth factor beta 1 (TGFB1) is a multifunctional cytokine with a key role in asthma airway inflammation and remodeling. Since elevated levels of this cytokine in airways might be associated with response to asthma therapy, the aim of this study was to investigate whether the presence of the polymorphism C-509T in the promoter of the TGFB1 gene is associated with response to montelukast. A group of 102 asthmatic patients was genotyped for the presence of the C-509T polymorphism by DNA sequencing and subjected to induced sputum sampling. Cells from sputum samples and BEAS 2B cells were treated with montelukast and endogenous TGFB1 expression was measured by quantitative real-time polymerase chain reaction. The promoter activity was analyzed by luciferase assays in BEAS 2B cells transfected with constructs carrying variants -509C and -509T of the TGFB1 gene promoter. After treatment with montelukast, the decrease in TGFB1 gene expression was greater for the -509TT genotype (58.9%) than for the -509CC and -509CT genotypes (49.6% and 31.8%, respectively) (P = 0.071). In BEAS 2B cells, expression of endogenous TGFB1 was reduced by about 27% after montelukast treatment, while luciferase activity of both promoter variants was increased after montelukast treatment (-509C allele: 48.3%, P = 0.060; and -509T allele: 100.5%, P = 0.062). A more intensive response was registered in the promoter containing the -509T allele, which had 135% higher activity than the -509C variant (P = 0.035). This study showed that the presence of the -509T allele in the TGFB1 promoter might modulate effects of montelukast on TGFB1 gene expression, but future studies are necessary, taking into consideration other genetic and nongenetic factors. It is of potential importance for clinical management of asthma to clarify the influence of the C-509T polymorphism on the response to treatment with montelukast.

Evaluation of transforming growth factor-beta1 gene expression in pterygium tissue of atopic patients

BackgroundThe exact pathogenesis of pterygium is still not fully understood. Growth factors are considered to play an important role in the formation of pterygium. Transforming growth factor (TGF)-β1 is considered to be one of the main mediators of fibroblast stimulation and tissue remodeling in allergic conditions. The objective of the present study was to investigate the association between TGF-β1 gene expression and pterygium in atopic and nonatopic participants. MethodsWe used questionnaires to record demographic and clinical information from patients who underwent pterygium excision surgery. Skin prick examination was done to confirm or rule out atopy in 30 patients with atopy (Case Group) and 30 individuals without atopy (Control Group). Additionally, measurement of serum immunoglobulin E, cytokines, including interleukin-4 and interferon-γ, and peripheral blood eosinophil count was performed to confirm atopy in 30 consecutive patients (Case Group). A semiquantitative reverse transcription polymerase chain reaction was performed to determine TGF-β1 gene expression in all individuals. ResultsTGF-β1 mRNA gene expression was significantly higher (p = 0.0001) in atopic patients 2.50 ± 1.11 compared to nonatopic individuals 1.40 ± 0.46. Eosinophil count and serum immunoglobulin E were significantly higher (p = 0.031 and p = 0.001, respectively) in atopic patients compared to the Control Group. Serum interleukin-4 was also significantly higher (p = 0.01) in atopic patients compared with nonatopic individuals. ConclusionExcess expression of TGF-β1 gene in pterygium tissue of atopic individuals suggests that growth factors play a role in the pathogenesis of pterygium.

614. Delivery of Micro-RNA Loaded Plasmid Through Nanoparticles Efficiently Modulate Transforming Growth Factor-Beta1 Expression in Healing Flexor Tendons: An In Vitro and In Vivo Study

Aims: Formation of adhesion around the healing tendon is a major cause of poor function of the extremities. Adhesions developed around healing digital flexor tendons are extremely harmful to active hand movement, and modulating its gene expression may be a promising approach to prevent adhesion formations. Because transforming growth factor (TGF)-beta1 is highly expressed in the adhesion tissues and is considered responsible for adhesion and scar formation, we propose to deliver micro-RNAs (miRNAs) to down-regulate expression of this key gene in order to prevent adhesions in the healing digital flexor tendon.Methods: Nanoparticles made of polylactic-co-glycolic acid were prepared and were then incorporated with plasmids expressing enhanced green fluorescence protein and miRNAs for inhibiting the transforming growth factor-beta1 gene expression. The cultured tenocytes from chicken toes were used to test efficiency of transfection of the cells by plasmid released from nanoparticles. Then 30 long toes from bilateral feet of 15 chickens were used because of their structural similarity to human digital flexor tendons. The toes were divided into 6 groups (5 tendons per group) according to injected nanoparticles and timing of harvesting samples after surgery. The 6 groups were 2-, 4- and 6-weeks after nanoparticle-plasmid (mock miRNA)-injected groups and 2-, 4- and 6-week nanoparticle-plasmid (miRNA TGF-beta1)-injected groups. Expression levels of TGF-beta1 in the tendons in different groups were evaluated with Western blotting. Tendon healing status was also evaluated.Results: In the in vitro setting, the tenocytes could be effectively transfected by the nanoparticle-plasmid complex. The expression of TGF-beta1 is significantly down-regulated in healing chicken flexor tendon treated with nanoparticle-plasmid at all three time-points after surgery (p < 0.05 or p < 0.01). Histology analysis did not demonstrate any significant inflammation or necrosis in tendons injected with nanoparticle-plasmid after surgery. The tendon healing status was not affected by use of nanoparticle-plasmid.Conclusions: Delivery of micro-RNA loaded plasmid through nanoparticles is a promising gene therapy of the injured digital flexor tendon. Our results show that this approach is a non-viral delivery method, and can efficiently modulate genes associated with adhesion formation, which may be a promising method to limit adhesion formations.

Protective effect of resveratrol against doxorubicin-induced cardiac toxicity and fibrosis in male experimental rats.

The possible effectiveness of resveratrol, a polyphenol present in different plants comprising berries, grapes and peanuts, on the prevention of doxorubicin-induced cardiac toxicity and fibrosis was investigated. Forty adult male Wistar albino rats were divided into four groups. Group I received normal saline, group II gavaged with resveratrol (20 mg/kg, daily for 4 weeks), group III received doxorubicin (2.5 mg/kg i.p. in six injections for 2 weeks; accumulative dose of 15 mg/kg), and group IV received doxorubicin + resveratrol (starting resveratrol intake 2 weeks before doxorubicin administration). Resveratrol significantly alleviated the increase in left ventricular lipid peroxidation, hydroxyproline, and tumor necrosis factor alpha levels as well as serum creatine kinase-myocardial band (CK-MB) activity and prevented the decrease in body and heart weights in doxorubicin-treated group. However, a marked protection against reduced glutathione content depletion and superoxide dismutase activity reduction was observed in the left ventricles of rats pretreated with resveratrol in combination with doxorubicin. Resveratrol also ameliorated the up-regulation of left ventricular caspase-3 and transforming growth factor-beta1 gene expression as well as left ventricular histopathological changes including necrosis and fibrosis induced by doxorubicin. Collectively, our results suggest that resveratrol provides a significant protection against doxorubicin-induced cardiotoxicity and fibrosis in rats. Therefore, it may be used as a promising cardioprotective agent in patients treated with doxorubicin due to malignant diseases. So, further clinical trials are required to confirm these findings.

Association of advanced vasculopathy and transforming growth factor-beta1 gene expression with immunoglobulin A nephropathy progression

The mechanism of IgA nephropathy (IgAN) progression remains ill-defined. In this prospective study, the prognostic role of clinical, histological and molecular markers over a 2-year follow-up was evaluated. Fifty-one patients with biopsy-proven IgAN were followed for 24months. Besides routine histology, the intrarenal gene expressions of cytokines and chemokines were quantified by reverse transcription quantitative real-time polymerase chain reaction, and the presence of lymphocytes and macrophages were immunohistochemically examined. Higher transforming growth factor-β1 and severe chronic vasculopathy (but not glomerulosclerosis, interstitial fibrosis or lymphocyte infiltrate) were associated with the IgAN progression 24months after biopsy. The gene expression of chemokine (C-C motif) ligands 2 and 5, hepatocyte growth factor, bone morphogenic protein-7 and transforming growth factor-β1 and the interstitial infiltrate of T and B lymphocytes and macrophages were significantly associated with serum creatinine and glomerular filtration rate at the time of biopsy. The intrarenal chemokine (C-C motif) ligand 2 and hepatocyte growth factor gene expression were associated with the proteinuria. Besides the known risk factors for chronic kidney disease, advanced vasculopathy and molecular signatures of fibrogenesis were associated with the IgAN progression.

Nifedipine inhibits advanced glycation end products (AGEs) and their receptor (RAGE) interaction-mediated proximal tubular cell injury via peroxisome proliferator-activated receptor-gamma activation

There is a growing body of evidence that advanced glycation end products (AGEs) and their receptor (RAGE) interaction evokes oxidative stress generation and subsequently elicits inflammatory and fibrogenic reactions, thereby contributing to the development and progression of diabetic nephropathy. We have previously found that nifedipine, a calcium-channel blocker (CCB), inhibits the AGE-induced mesangial cell damage in vitro. However, effects of nifedipine on proximal tubular cell injury remain unknown. We examined here whether and how nifedipine blocked the AGE-induced tubular cell damage. Nifedipine, but not amlodipine, a control CCB, inhibited the AGE-induced up-regulation of RAGE mRNA levels in tubular cells, which was prevented by the simultaneous treatment of GW9662, an inhibitor of peroxisome proliferator-activated receptor-γ (PPARγ). GW9662 treatment alone was found to increase RAGE mRNA levels in tubular cells. Further, nifedipine inhibited the AGE-induced reactive oxygen species generation, NF-κB activation and increases in intercellular adhesion molecule-1 and transforming growth factor-beta gene expression in tubular cells, all of which were blocked by GW9662. Our present study provides a unique beneficial aspect of nifedipine on diabetic nephropathy; it could work as an anti-oxidative and anti-inflammatory agent against AGEs in tubular cells by suppressing RAGE expression via PPARγ activation.

Analysis of Correlation between the Process of Thyroid Fibrosis and TGFB1 Gene Expression Level in Fine-needle Aspiration Biopsy (FNAB) Thyroid Specimens Collected from Patients with Hashimoto's Thyroiditis and Non-toxic Goitre

Transforming growth factor beta 1 (TGFB1) stimulates the production of various extracellular matrix components; at the same time, it inhibits matrix degradation. These actions of TGFB1 contribute to tissue repair, however, an altered expression of TGFB1 can be a causative factor of fibrosis processes, including thyroid fibrosis which follows chronic thyroiditis. The aim of our study was to examine a potential correlation between TGFB1 gene expression level in fine-needle aspiration biopsy (FNAB) thyroid specimens and fibrosis of the thyroid gland in two types of thyroid lesions. Fibrosis of the thyroid tissue was assessed, based on the expression levels of fibrosis-associated genes (COL1A1 and COL3A1) in thyroid FNAB samples, on the FNAB specimen cellularity and other features of the tissue fibrosis assessed during cytological examination, as well as on the size of thyroid gland and its function. Following routine cytological examination, 63 thyroid FNAB specimens, received from patients with Hashimoto's thyroiditis (HT, n=30) and non-toxic goitre (NTG, n=33), were quantitatively evaluated regarding TGFB1, COL1A1 and COL3A1 expression level by real-time PCR in the ABI PRISM 7500 Sequence Detection System. The obtained results showed statistically significant differences regarding the expression level (RQ) of TGFB1 and of COL1A1 genes between the groups with HT and with NTG (higher expression in HT group). No significant differences, concerning the expression level of COL3A1 gene, were observed for the studied groups (HT vs. NTG). In HT group statistically significant correlation was found between TGFB1 gene and COL3A1 gene expression levels (p<0.05). The correlation in question might suggest excessive extracellular matrix deposition and could--possibly--contribute to thyroid fibrosis mechanism in the course of chronic thyroiditis.

Endogenous transforming growth factor (TGF) beta1 promotes differentiation of smooth muscle cells from embryonic stem cells: stable plasmid-based siRNA silencing of TGF beta1 gene expression

Transforming growth factor (TGF) beta1 has been shown to promote differentiation of smooth muscle cells (SMC) from some precursor cells. Whether endogenous TGF beta1 also contributes to SMC differentiation during embryogenesis, however, remains unclear. In this study, a plasmid-based TGF beta1 RNA interference embryonic stem (ES) cell line was constructed. Morphological observation showed that TGF beta1 knockdown significantly prevented differentiated cells from outgrowing from ES cells-derived embryoid bodies (EBs). Immunofluorescence staining indicated that SM alpha-actin-positive cells were confluent and dense in the control group but dispersed in the TGF beta1 knockdown group. RT-PCR and western blot suggested that TGF beta1 knockdown resulted in a decrease in the expression of early SMC markers SM alpha-actin and myocardin in EBs. Both the retarded extension of cell outgrowth and the decrease in SM alpha-actin and myocardin expression could not be rescued by addition of exogenous TGF beta1. These data suggest that endogenous TGF beta1 promotes differentiation of SMC from ES cells.

Activin-Like Kinase 5 (ALK5) Mediates Abnormal Proliferation of Vascular Smooth Muscle Cells from Patients with Familial Pulmonary Arterial Hypertension and Is Involved in the Progression of Experimental Pulmonary Arterial Hypertension Induced by Monocrotaline

Mutations in the gene for the transforming growth factor (TGF)-beta superfamily receptor, bone morphogenetic protein receptor II, underlie heritable forms of pulmonary arterial hypertension (PAH). Aberrant signaling via TGF-beta receptor I/activin receptor-like kinase 5 may be important for both the development and progression of PAH. We investigated the therapeutic potential of a well-characterized and potent activin receptor-like kinase 5 inhibitor, SB525334 [6-(2-tert-butyl-5-{6-methyl-pyridin-2-yl}-1H-imidazol-4-yl)-quinoxaline] for the treatment of PAH. In this study, we demonstrate that pulmonary artery smooth muscle cells from patients with familial forms of idiopathic PAH exhibit heightened sensitivity to TGF-beta1 in vitro, which can be attenuated after the administration of SB525334. We further demonstrate that SB525334 significantly reverses pulmonary arterial pressure and inhibits right ventricular hypertrophy in a rat model of PAH. Immunohistochemical studies confirmed a significant reduction in pulmonary arteriole muscularization induced by monocrotaline (used experimentally to induce PAH) after treatment of rats with SB525334. Collectively, these data are consistent with a role for the activin receptor-like kinase 5 in the progression of idiopathic PAH and imply that strategies to inhibit activin receptor-like kinase 5 signaling may have therapeutic benefit.

Bradykinin Attenuates Hepatocellular Damage and Fibrosis in Rats With Chronic Liver Injury

Recent studies have suggested that the kallikrein-kinin system regulates tissue fibrogenesis. We hypothesize that bradykinin (BK), the main effector peptide of this system, regulates hepatic fibrogenesis. Kallikrein-kinin system components were studied by quantitative reverse-transcription polymerase chain reaction analysis, immunohistochemistry, and Western blotting. The effect of bradykinin on liver injury was studied by infusing saline or bradykinin (1 and 100 ng/kg/min) through a subcutaneous pump into carbon tetrachloride-treated rats and mice treated with Fas-stimulating antibody. Bradykinin effects were studied in cultured hepatic stellate cells (HSCs) and hepatocytes. Bradykinin receptors and kallikrein-1 were detected in both normal and fibrotic human livers and HSCs. BK receptors were up-regulated in fibrotic livers and activated HSCs. Bradykinin infusion reduced liver damage, as indicated by decreased aminotransferase serum levels and reduced histologic necroinflammatory score without inducing changes in arterial pressure. Moreover, bradykinin attenuated hepatic fibrosis, as indicated by reduced collagen accumulation, smooth muscle alpha-actin content, as well as decreased pro-collagen-alpha1(I) and transforming growth factor-beta1 gene expression. Bradykinin infusion reduced hepatocellular apoptosis induced by anti-Fas-receptor antibody. HSCs responded to bradykinin with intracellular calcium mobilization. Bradykinin reduced procollagen-alpha1(I) and transforming growth factor-beta1 gene expression and induced matrix metalloproteinase-2 activation. Finally, BK induced prosurvival and proliferative intracellular signaling in primary hepatocytes. Bradykinin attenuates liver damage and fibrosis development in a rat model of chronic liver injury. Therefore, activation of the kallikrein-kinin system may be a new therapeutic approach to the management of chronic liver disease.

Promoter sequences involved in transforming growth factor beta1 gene induction in HaCaT keratinocytes after gamma irradiation.

Transforming growth factor beta 1 (TGFB1) is a cytokine involved in the development of both acute and late cutaneous radiation syndromes. We previously demonstrated that ionizing radiation induces TGFB1 expression in vivo in pig skin within a few hours. The purpose of the present study was to develop an in vitro human model to identify the mechanisms of this early activation. Accordingly, human HaCaT keratinocytes were irradiated with a single dose of 20 Gy. First, radiation-induced TGFB1 overexpression was checked at both the transcriptional and transductional levels in HaCaT cells. Then electrophoretic mobility shift assays (EMSA) and transient transfection with various TGFB1 promoter constructs were used to identify the sequences involved in regulating this promoter. EMSA analysis showed the induction of nuclear protein binding activity by gamma irradiation to the -365 AP1 sequence (TGTCTCA), suggesting the involvement of AP1 sequences in the regulation of TGFB1 transcription. In gene reporter assays, maximal TGFB1 promoter activation was found for the longest construct, which contains two AP1 sequences. However, assays with constructs including deletions showed that these two AP1 sequences were not sufficient to confer TGFB1 inducibility. These results showed for the first time, to our knowledge, that transcriptional regulation is involved in radiation-induced activation of TGFB1 gene expression.

Extracellular collagen regulates expression of transforming growth factor-beta1 gene.

A complex interrelationship exists between the extracellular matrix and cytokine signaling in articular chondrocytes. We sought to determine whether the extracellular matrix serves as a regulatory component of transforming growth factor-beta1 expression. Bovine articular chondrocytes were isolated and resuspended in alginate, yielding final extracellular protein concentrations of 0 to 1.5% (wt/vol) for type-II or type-I collagen. Cultures were maintained for 7 days in the presence or absence of transforming growth factor-beta1-supplemented medium (10 ng/ml). The amount of transforming growth factor-beta1 mRNA was examined with quantitative competitive reverse transcription-polymerase chain reaction analysis. The results indicate that exogenous transforming growth factor-beta1 stimulates endogenous transforming growth factor-beta1 mRNA expression approximately 8-fold. This effect depended on the concentration of extracellular type-II collagen. As the concentration of extracellular type-II collagen is increased, the expression of transforming growth factor-beta1 mRNA decreases in both basal and transforming growth factor-beta1-stimulated cultures. Exogenous extracellular type-I collagen also served to negatively modulate transforming growth factor-beta1 gene expression but with a different concentration profile. The results demonstrate that transforming growth factor-beta1 mRNA expression was upregulated by exogenous transforming growth factor-beta1 and was downregulated by extracellular type-I and type-II collagens. The profoundly different effects on transforming growth factor-beta1 expression by the two collagens are consistent with those reported for mammary epithelial cells and likely serve as a negative feedback mechanism to preserve tissue homeostasis.

Transforming growth factor-beta gene expression in avian Low Score Normal pectoral muscle

The avian Low Score Normal (LSN) genetic muscle weakness is phenotypically characterized by a reduction in the ability of birds to right themselves from a supine position. In previous studies, LSN birds exhibited elevated levels of decorin transcript and protein at embryonic Day 20 and a large increase in collagen crosslinking at 6 wk posthatch. Transforming growth factor-beta (TGF-beta) expression has been reported to control decorin expression. Steady state levels of TGF-beta1 and TGF-beta2 transcripts were determined in ovo and posthatch in order to initiate an investigation of the mechanism underlying decorin expression. On embryonic Day 20 through 1 wk posthatch, TGF-beta2 transcript levels were elevated, whereas an increase in TGF-beta1 was only noted at 1 d posthatch. These data suggest that the increase in decorin expression may be associated with a modification in a TGF-beta signal transduction pathway.

Role of bradykinin B2 receptors in neonatal kidney growth.

The kallikrein-kinin system is developmentally expressed in newborn kidneys. In addition, bradykinin (BK) is mitogenic in cultured glomerular mesangial cells. However, the role of endogenous BK in postnatal renal development has not been defined. In this study, the role of the BK-B2 receptor in neonatal kidney growth in the rat was examined. RNA blot analysis and semiquantitative reverse transcription-polymerase chain reaction showed that BK-B2 mRNA levels were approximately 30- to 40-fold higher in newborn than adult kidneys. Treatment of newborn rats with the selective BK-B2 antagonist, Hoe 140 (600 micrograms/kg per day, sc), from days 1 through 14 of life significantly reduced body weight, kidney-to-body weight ratios, and kidney DNA content, compared with saline-treated controls. Hoe 140 treatment had no effect on kidney protein or RNA content or the expression of transforming growth factor-beta mRNA. The growth retardation induced by BK-B2 blockade was observed only in the kidney and, to a lesser extent, in the heart. BK-B2 blockade had no effect on renal growth in adult rats, suggesting that these effects are developmentally regulated. In contrast to Hoe 140 treatment, neonatal protein undernutrition resulted in a generalized reduction in kidney DNA, RNA, and protein contents; increased renal transforming growth factor-beta gene expression; and decreased renal kallikrein expression and enzymatic activity. The results suggest that activation of BK-B2 receptor expression in the neonatal kidney plays an important role in the regulation of DNA synthesis during the latter stages of nephrogenesis.

2197 Interrelationship between transforming growth factor-beta gene expression and radiation fibrosis in C57BL/6 mouse lung

2197 Interrelationship between transforming growth factor-beta gene expression and radiation fibrosis in C57BL/6 mouse lung

Procollagen types I and III and transforming growth factor-beta gene expression in the arterial wall after exposure to periarterial blood.

The stiffening and thickening of the arterial wall after subarachnoid hemorrhage may reflect increased connective tissue. The purpose of this study was to examine the nature of collagen synthesis in response to periarterial blood. Rat femoral arteries were exposed to periarterial blood for varying lengths of time (control, 1, 3, 7, and 14 d). Dot-blot analysis of total ribonucleic acid extracted from the arteries (n = 10 to 15 animals each) demonstrated that the expression of procollagen Types I and III messenger ribonucleic acid increased at 7 (threefold) and 14 days. The expression of transforming growth factor-beta (TGF-beta), an important regulator of collagen synthesis, was markedly increased by 3 days (threefold), followed by a gradual decline. There were marked differences in procollagen Types I and III and TGF-beta gene expression between arteries exposed to blood and sham-operated arteries for a period of 7 days (n = 25 animals). Northern blot analysis of total ribonucleic acid extracted from cultured vascular smooth muscle cells showed that the treatment with a higher concentration of serum for 48 hours increased the expression of procollagen Types I and III and TGF-beta, whereas exposure to oxyhemoglobin did not. After exposure to periarterial blood, arterial walls show increased synthesis of procollagen Types I and III, perhaps a response to the increased secretion of TGF-beta, which in turn could be the result of exposure to serum factors.

Procollagen Types I and III and Transforming Growth Factor-Beta Gene Expression in the Arterial Wall after Exposure to Periarterial Blood

Procollagen Types I and III and Transforming Growth Factor-Beta Gene Expression in the Arterial Wall after Exposure to Periarterial Blood