Transforming growth factor-beta1 and protein kinase C synergistically activate the c-fos serum response element in myocardial cells

Stimulation of NMDA receptor increases NO-dependent cGMP synthesis. A significantly higher cGMP level was observed in hippocampus (about 8-fold increase) than in cerebral cortex (2.5-fold increase), as compared to basal value. The activity of NO synthase (NOS) and the basal level of cGMP in unstimulated slices were only slightly higher in hippocampus than in the cortex. About 60% of NOS total activity was found in the brain membrane fraction. The enzyme activity was not affected by glucocorticoids, even after 20 days of hydrocortisone treatment in dose of 40 mg/kg b.w. Brain ischemia induced by ligation of the both common carotid arteries in gerbils (Meriones unquiculatus) significantly increased NOS activity as well as cGMP and putrescine concentrations but decreased mono-ADP-ribosolation of proteins. Changes of NOS activity and cGMP concentration evoked by ischemia were decreased by specific inhibitor of the neuronal form of NOS (nNOS), 7-nitrodazole and the inhibitor of guanylate cyclase, LY 83,583 administered respectively in a dose of 25 mg/kg b.w. and 6 mg/kg b.w. 5 min. before ischemia. The inhibitor of nNOS, 7NI, did not change the concentration of putrescine during ischemia and reperfusion. Our results indicated that these inhibitors could protect the brain against excessive production of nitric oxide and biochemical processes dependent on it. In this way they may offer a new strategy in the therapy of brain ischemia.     

Transforming growth factor-beta 3

Transforming Growth Factor-Beta (TGF-beta) is the general name for a family of naturally-occurring polypeptides which have multiple regulatory effects on cell proliferation and differentiation. Over the last decade it has become apparent that TGF-betas can be produced by most cell types and exert a wide range of effects in a context-dependent autocrine, paracrine or endocrine fashion via interactions with distinct receptors on the cell surface. This review summarizes current knowledge concerning the molecular and cellular biology of TGF-beta 3, the most recently described mammalian isoform, and focuses on those physiological actions which may lead to clinical applications, particularly in the indication areas of wound healing and chemoprotection.     

Transforming growth factor-beta1 in hemangioma of the ovary

OBJECTIVE: Anastomotic pseudoaneurysms continue to be a late complication of vascular surgery, particulary following prosthetic graft procedures. The purpose of this study was to investigate if a previously reported increase in interval between the original operation and the development of pseudoaneurysm was related to a change in incidence. DESIGN: Retrospective study. METHODS: We reviewed the records of 76 patients who presented with 90 femoral pseudo-aneurysms and underwent reconstructive procedures from January 1989 to June 1994. The median age was 69 years (range: 39-83). In the same time period all femoral artery anastomosis operations were recorded. RESULTS: The incidence of femoral pseudo-aneurysms in Copenhagen was approximately 4.3%. CONCLUSIONS: A previously reported increase in interval between primary operation and aneurysms formation was not related to a change in incidence during the same time period.     

Transforming growth factor-beta 1 stimulates articular chondrocyte proteoglycan synthesis and induces osteophyte formation in the murine knee joint

BACKGROUND: High concentrations of active transforming growth factor-beta (TGF-beta) have been found in synovial fluids from arthritic joints. TGF-beta stimulates articular cartilage proteoglycan synthesis and suppresses proteoglycan degradation in vitro. In an earlier study, we found no effect on cartilage proteoglycan metabolism shortly after a single intra-articular injection of TGF-beta 1. In the present study, we used multiple intra-articular injections and a longer time-scale. EXPERIMENTAL DESIGN: TGF-beta 1 was injected into the murine knee joint to gain insight in the consequences of its overproduction in joint diseases. This was evaluated using histologic sections of the whole knee joint and measurements of articular cartilage proteoglycan synthesis and content. RESULTS: At 6 hours after a single TGF-beta 1 injection, recruitment of polymorphonuclear leukocytes (PMNs) was observed. After 24 hours, the amount of inflammatory cells had already decreased. Multiple TGF-beta 1 injections induced synovial hyperplasia and synovitis predominantly consisting of cells of the macrophage/monocyte lineage. Both single and multiple TGF-beta 1 injections induced strong and long-lasting stimulation of articular cartilage proteoglycan synthesis. This in vivo stimulation of proteoglycan synthesis was similar in cartilage of young (3 months) and old mice (18 months). Multiple TGF-beta 1 injections resulted in an increased GAG content in patellar cartilage. After triple TGF-beta 1 injections, impressive osteophyte formation was noted at specific sites. The size and the localization of osteophytes was identical in young and old mice. Interestingly, the localization of TGF-beta 1-induced osteophytes was very similar to that of osteophytes observed in experimental arthritis and osteoarthritis models, suggesting a role for endogenous TGF-beta in osteophyte formation during joint pathology. CONCLUSIONS: Our data indicate that TGF-beta 1 injection into a normal joint induces inflammation, synovial hyperplasia, osteophyte formation, and prolonged elevation of proteoglycan synthesis and content in articular cartilage.     

Transforming growth factor-beta inhibits progesterone-induced enkephalinase expression in human endometrial stromal cells

The specific activity of enkephalinase in endometrial tissue of nonpregnant ovulatory women is correlated in a highly significant, positive manner with the plasma level of progesterone. The specific activity and levels of enkephalinase messenger ribonucleic acid and immunoreactive protein also are increased in human endometrial stromal cells in culture by treatment with a synthetic progestin, medroxyprogesterone acetate (MPA), in a time- and dose-dependent manner. From an analysis of the temporal relationship between the specific activity and half-life of enkephalinase in endometrial tissue and the level of progesterone in plasma, it appeared highly likely that some mechanism, in addition to progesterone withdrawal, was operative to reduce enkephalinase activity in endometrium during the late luteal phase of the ovarian cycle before progesterone levels had declined below those known to be effective for progesterone action. In stromal cells previously (and concurrently) treated with MPA (10(-9) mol/L), the addition of transforming growth factor-beta 1 (TGF beta 1) or TGF beta 2 (1 ng/mL) to the medium caused a decrease in enkephalinase specific activity despite the continued presence of MPA. The half-life of enkephalinase (activity) in stromal cells treated with MPA plus TGF beta 1 was 2.8 days, which is similar to the computed half-life for enkephalinase in endometrial tissue during the mid- to late secretory phase of the endometrial cycle (2.5 days). Simultaneous treatment of endometrial stromal cells with MPA (10(-9) mol/L) and TGF beta 1 (1 ng/ mL) prevented the progestin-induced increase in enkephalinase specific activity and immunoreactive enkephalinase protein. Thus, TGF beta acts to oppose the progesterone-induced increase in enkephalinase expression in endometrial stromal cells, even in the continued presence of MPA.     

Transforming growth factor-beta 1 hyperexpression in African American end-stage renal disease patients

Like amphetamine, scopolamine produces locomotor stereotypy (repetitive routes of locomotion) in an open field. To determine whether locomotor stereotypy is a common behavioral effect of anticholingeric agents, several doses of the anticholinergic dexbenzetimide were tested for the ability to produce locomotor stereotypy; like scopolamine, dexbenzetimide produced locomotor stereotypy. To investigate a possible role of dopamine in anticholinergic-induced locomotor stereotypy, we tested the ability of the dopamine D1 antagonist SKF 83566 and the D2 antagonist sulpiride to block the locomotor stereotypy induced by scopolamine as well as dexbenzetimide. SKF 83566 blocked scopolamine- and dexbenzetimide-induced locomotor stereotypy; sulpiride did not reduce dexbenzetimide-induced locomotor stereotypy, but enhanced scopolamine-induced locomotor stereotypy. Hyperlocomotion was reduced by both dopamine antagonists. Results are interpreted in support of the notion that dopamine is the likely candidate mediating locomotor stereotypy.     

Transforming growth factor-beta expression in mouse lung carcinogenesis

Transforming growth factor-beta (TGF-beta) is a multifunctional growth modulator that inhibits the proliferation of many epithelial cells while stimulating the proliferation of most fibroblasts. To examine the role of TGF-beta in mouse lung chemically induced tumorigenesis, expression of the TGF-beta 1, -beta 2, and -beta 3 proteins was examined in A/J mice treated with the carcinogen urethane to induce lung adenomas using immunohistochemical staining analysis. Immunostaining for the TGF-beta ligands was detected in the epithelium of the bronchioles of untreated A/J mice with immunostaining being more intense for TGF-beta 1 than for TGF-beta 2 and TGF-beta 3; immunostaining for each TGF-beta ligand was also detected in the bronchiolar epithelium of urethane-treated A/J mice at levels similar to untreated mice. Immunostaining for the TGF-beta ligands was also detected in adenomas by 2 months; staining for TGF-beta 1, -beta 2, and -beta 3 in adenomas was detected at levels comparable with bronchioles. Following treatment with urethane for 8 months, immunostaining for TGF-beta s 1, 2, and 3 in bronchioles persisted at levels comparable to that in normal bronchioles and also persisted in adenomas, with staining for the TGF-beta ligands being very prominent on the edge of the tumor. Expression of TGF-beta 1 mRNA was examined in urethane-treated mouse lung tissue using Northern blot hybridization; here, expression of TGF-beta 1 mRNA increased 2-fold in 3-month urethane-treated lung tissue and an additional 2.5-fold by 8 months following urethane administration. Expression of TGF-beta 1 mRNA was also examined in nontumorigenic and tumorigenic mouse lung cells; in these cells, expression of TGF-beta 1 mRNA was higher in the tumorigenic cells than in the nontumorigenic cell line. These data show that there is an increase in expression of TGF-beta 1 during tumorigenesis and suggest that TGF-beta may play an important role in mouse lung carcinogenesis induced by urethane.     

Transforming growth factor-beta: a general review

Three isoforms of Transforming Growth Factor-beta (TGF-beta 1, beta 2 and beta 3) exist in mammals. They play critical roles in growth regulation and development. Each isoform is encoded by a unique gene on different chromosomes. All three of these growth factors are secreted by most cell types, generally in a latent form, requiring activation before they can exert biological activity. This activation of latent TGF-beta, which may involve plasmin, thrombospondin and possibly acidic microenvironments, appears to be a crucial regulatory step in controlling their effects. The TGF-betas possess three major activities: they inhibit proliferation of most cells, but can stimulate the growth of some mesenchymal cells; they exert immunosuppressive effects; and they enhance the formation of extracellular matrix. Two types of membrane receptors (type I and type II) possessing a serine/threonine kinase activity within their cytoplasmic domains are involved in signal transduction. Inhibition of growth by the TGF-betas stems from a blockage of the cell cycle in late G1 phase. Among the molecular participants concerned in G1-arrest are the Retinoblastoma (Rb) protein and members of the Cyclin/Cyclin-dependent kinase/Cyclin dependent kinase inhibitor families. In the intact organism the TGF-betas are involved in wound repair processes and in starting inflammatory reactions and then in their resolution. The latter effects of the TGF-betas derive in part from their chemotactic attraction of inflammatory cells and of fibroblasts. From gene knockout and from overexpression studies it has been shown that precise regulation of each isoform is essential for survival, at least in the long term. Several clinical applications for certain isoforms have already shown their efficacy and they have been implicated in numerous other pathological situations.     

Transforming growth factor-beta enhances adhesion of melanoma cells to the endothelium in vitro

Melanoma invasion requires migration through the vascular barrier. An early event in this process is the adhesion of metastatic cells to the endothelium. To elucidate the role of TGF-beta in the regulation of this process, human melanoma SK-MEL24 cells were labelled with [5'-(3)H]-thymidine and co-cultured with bovine pulmonary artery endothelial-cell monolayers. Radioactivity was assumed to be proportional to the number of SK-MEL24 cells bound to the endothelium. A low number of melanoma cells adhered to endothelial cells in a time-related manner. Pretreatment for 24 hr with 0.001 to 10 ng/ml TGF-beta1 or TGF-beta2 of both cell types enhanced melanoma-endothelium adhesion in a dose-dependent manner. Both melanoma and endothelial cells expressed RI- and RII-type TGF-beta receptors. The effect of TGF-beta was abolished by co-incubation with the proteoglycan decorin. Conditioned media from melanoma-endothelium co-cultures contained latent TGF-beta and failed to affect cell-cell adhesion. However, activation of TGF-beta by heating the medium or reducing the pH, increased melanoma-endothelium adhesion to an extent similar to that of the TGF-beta administered to the cultures. Zimography demonstrated that both cell types expressed urokinase-type plasminogen activator (uPA). Addition of plasminogen to the co-cultures, which was likely to be activated to plasmin by uPA, resulted in activation of TGF-beta and parallel stimulation of melanoma-endothelium adhesion. In conclusion, TGF-beta may enhance adhesion of melanoma cells to the endothelium, playing a relevant autocrine/paracrine role in the progression of invasive melanoma.     

Cyclic stretching force selectively up-regulates transforming growth factor-beta isoforms in cultured rat mesangial cells

Glomerular distention from increased intraglomerular pressure stretches mesangial cells (MCs). Stretching MCs in culture stimulates extracellular matrix accumulation, suggesting that this may be a mechanism for glomerular hypertension-associated glomerulosclerosis. We examined whether mechanical stretching serves as a stimulus for the synthesis and activation of the prosclerotic molecule transforming growth factor (TGF)-beta, thus providing a potential system for auto-induction of extracellular matrix. Rat MCs cultured on flexible-bottom plates were subjected to cyclic stretching for up to 3 days and then assayed for TGF-beta mRNA, secretion of TGF-beta, and localization of active TGF-beta by immunostaining. MCs contained mRNA for all three mammalian isoforms of TGF-beta. Cyclic stretching for 36 hours increased TGF-beta1 and TGF-beta3 mRNA levels approximately twofold, without altering the levels of TGF-beta2 mRNA. This was followed at 48 to 72 hours by the increased secretion of both latent and active TGF-beta1. Latent, but not active, TGF-beta3 secretion also increased whereas the levels of TGF-beta2 were unaffected by mechanical force. The stretching force in this system is unequally distributed over the culture membrane. Localization of active TGF-beta by immunostaining demonstrated that the quantity of cell-associated cytokine across the culture was directly proportional to the zonal amplitude of the stretching force. These results demonstrate that stretching force stimulates MCs to selectively release and activate TGF-beta1. This mechanical induction of TGF-beta1 may help explain the increased extracellular matrix associated with intraglomerular hypertension.     

Transforming growth factor--alpha stimulates chemotaxis of osteoblasts and osteoblast-like cells in vitro

Homeostatic turnover of bone is believed to be regulated in part by growth factors present in the surrounding environment. The first step during the bone formation process is the recruitment of osteoblasts from the surrounding intact bone to the resorption site. In this study, the effects of TGF-alpha on osteoblast chemotaxis was investigated. Cultures of rat osteoblasts and human osteoblast-like cells were examined for chemotaxis in response to increasing concentrations of TGF-alpha utilizing a modified Boyden Chamber technique. TGF-alpha stimulated a dose-dependent increase in chemotaxis by both cell populations. These results indicate that TGF-alpha may be playing an important role in the early stages of bone matrix regeneration by stimulating osteoblast chemotaxis.     

Transforming growth factor-beta inhibits interferon-gamma secretion by lymphokine-activated killer cells stimulated with tumor cells

The effect of transforming growth factor-beta (TGF-beta) secreted by glioblastoma (T98G) cells on the secretion of interferon-gamma (IFN-gamma) by lymphokine-activated killer (LAK) cells stimulated with tumor cells was investigated in cocultures of LAK and Daudi cells supplemented with T98G culture supernatant, T98G culture supernatant preincubated with anti-TGF-beta 1 and anti-TGF-beta 2 neutralizing antibodies, anti-TGF-beta 1 and anti-TGF-beta 2 antibodies, or natural human TGF-beta 1 or recombinant human TGF-beta 2. LAK cells were incubated with anti-TGF-beta 1 and anti-TGF-beta 2 antibodies, and with T98G cells of which the supernatant contained both active and latent forms of TGF-beta 1 and TGF-beta 2, with or without neutralizing antibodies. Addition of the supernatant from T98G cells to LAK/Daudi culture caused inhibition of IFN-gamma secretion by LAK cells. The inhibition was abolished by pretreatment of the supernatants with anti-TGF-beta antibodies. Addition of TGF-beta 1 and TGF-beta 2 to the LAK/Daudi culture inhibited IFN-gamma secretion by LAK cells in a dose-dependent manner. Addition of anti-TGF-beta antibodies to the LAK culture resulted in increased IFN-gamma secretion. T98G cells failed to stimulate LAK cells to secrete more IFN-gamma. Addition of anti-TGF-beta antibodies to the LAK-T98G culture resulted in increased IFN-gamma secretion by LAK cells. These results suggest that most malignant glioma cells which secrete high levels of TGF-beta can inhibit IFN-gamma secretion by LAK cells even after tumor cell stimulation.     

Negative regulation of interleukin-1beta-activated neutral sphingomyelinase by protein kinase C in rat mesangial cells

Endogenous ceramide is produced by the action of acidic or neutral sphingomyelinases (SMase) in response to stimuli such as proinflammatory cytokines or other inducers of stress. Interleukin-1beta (IL-1beta) is known to stimulate ceramide formation in rat renal mesangial cells; however, the respective subtype of SMase and its regulation have not been investigated. We found that IL-1beta induced an increase in endogenous ceramide levels via the action of a neutral SMase but not an acidic SMase in rat mesangial cells. Cytokine-induced activation of neutral SMase was inhibited by stimulation of protein kinase C (PKC) by the phorbol ester TPA which caused a reduction of ceramide back to control levels. This inhibitory effect of TPA was reversed by the specific PKC-inhibitor Ro-318220. Long-term incubation (24 h) of mesangial cells with TPA, which downregulates PKC-alpha, -delta, and -epsilon isoenzymes, resulted in a recovery of IL-1beta-stimulated neutral SMase activity as well as ceramide formation. These data implicate an important modulatory function of PKC in ceramide production in IL-1beta-activated mesangial cells.     

Ornithine decarboxylase over-expression stimulates mitogen-activated protein kinase and anchorage-independent growth of human breast epithelial cells

Inactivation of one X chromosome (X inactivation) in female mammals results in dosage compensation of X-chromosomally encoded genes between sexes. In the embryo proper of most mammals X inactivation is thought to occur at random with respect to the parental origin of the X chromosome. We determined on the cellular level the expression of the X-chromosomally encoded protein dystrophin in skeletal and cardiac muscle of female mice heterozygous for a null mutation of the dystrophin gene (mdx/+). In all muscles investigated (cardiac, anterior venter of digastric muscle, biceps brachii and tibialis anterior muscle) we found a mosaic expression of dystrophin-expressing versus non-expressing cells and determined their proportion with respect to the parental origin of the X chromosome. In all groups of mdx/+ mice the level and pattern of dystrophin expression were found to be dependent on the parental origin of the mdx mutation. Additionally, the extent of dystrophin expression was clearly dependent on the mouse strains (C57BL/10 and BALB/c) used to produce heterozygous mdx/+ mice. Variable differences and patterns of dystrophin expression in skeletal versus cardiac muscle were found that were strictly dependent on the parental source of the mdx mutation and the strain used to breed mdx/+ mice. Moreover, dystrophin expression was found to be different between the right side and the left side of the body in individual muscles, and this difference was clearly dependent on the parental origin of the X chromosome. Our data provide evidence that in the mouse embryo proper there is a non-random distribution of cells showing inactivation of the paternal versus the maternal X chromosome in skeletal and cardiac muscle, indicating a non-random X-inactivation. Besides gametic imprinting, strain-, tissue and position-dependent factors also appear to bias X inactivation.     

Transforming growth factor-beta 2-related-decidual suppressor factor is not related to TJ6 protein

Based on the dual-interactive feedback model, dark focus and dark vergence designate a point on a line describing the response AC/A ratio. In order to verify the relationship between dark focus and dark vergence, we predicted the dark vergence from the measured dark focus when the measurements were based on the response-based calculated and gradient AC/A ratios. For 10 subjects, the correlations between predicted and measured dark vergence values were high. The prediction was better when using the gradient AC/A ratio.