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Mallat Z, Tedgui A. The role of transforming growth factor beta in atherosclerosis: novel insights and future perspectives. Curr Opin Lipidol 2002; 13:523-9. [PMID: 12352016 DOI: 10.1097/00041433-200210000-00008] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
PURPOSE OF REVIEW Atherosclerosis is a disease of the arterial wall that seems to be tightly modulated by the local inflammatory balance. Transforming growth factors beta 1, 2 and 3 are cytokines/growth factors with broad activities on cells and tissues in the cardiovascular system, and have been suggested to play a role in the pathogenesis of atherosclerosis. RECENT FINDINGS In the present review, we discuss recent developments in the role of transforming growth factor beta in the regulation of the immuno-inflammatory balance that modulates atherosclerosis. Such studies strongly suggest that the inhibition of endogenous transforming growth factor beta signalling favours the development of atherosclerotic lesions with an increased inflammatory component (T cells and macrophages) and decreased collagen content, features that are characteristic of unstable atherosclerotic plaques. SUMMARY Transforming growth factor beta is identified as a critical modulator of the immuno-inflammatory balance in atherosclerosis, and a crucial plaque-stabilizing factor. Future studies should aim at defining the precise molecular mechanisms responsible for this protective effect, and developing immunomodulatory strategies based on the promotion of transforming growth factor beta activity (T regulatory T helper type 3 cells) to limit disease complications.
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Affiliation(s)
- Ziad Mallat
- INSERM U541, Circulation Paris VII Institut Fédératif de Recherche, Hôpital Lariboisière, 41 Boulevard de la Chapelle, 75010 Paris, France.
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102
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Chen G, Khalil N. In vitro wounding of airway smooth muscle cell monolayers increases expression of TGF-beta receptors. Respir Physiol Neurobiol 2002; 132:341-6. [PMID: 12208092 DOI: 10.1016/s1569-9048(02)00111-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
During an exacerbation of asthma, there is bronchial epithelial cell injury and influx of inflammatory cells. In these instances, the release of proteases and various cytokines could lead to injury of the airway smooth muscle cells (ASMCs). Airway remodeling is a characteristic finding in asthma but the role of ASMC injury in remodeling is unknown. Previously, we demonstrated that mechanical wounding of confluent monolayers of bovine ASMCs resulted in the release of biologically active transforming growth factor-beta1 (TGF-beta1), which in turn, induced collagen I expression. In the present study, we demonstrate that after mechanical wounding, ASMCs had an increased expression of the signal transducing TGF-beta receptors TbetaR-I and TbetaR-II as detected by flow cytometry and Western analysis. Corticosteroids are standard therapy in asthma and the presence of dexamethasone decreased wound-induced release of TGF-beta1 and the expression of collagen I, fibronectin, and TbetaR-II. These results suggest that ASMC injury may play an important role in airway fibrosis mediated by TGF-beta1, which can be prevented by the use of corticosteroids.
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Affiliation(s)
- Gang Chen
- Division of Respiratory Medicine, Department of Medicine, Vancouver Hospital and Health Sciences Centre, The University of British Columbia, 655 West 12th Avenue, Vancouver, BC, Canada V5Z 4R4
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103
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Abstract
A new hypothesis is presented, which explains how exponential tissue concentration gradients of biphasic morphogens that inhibit and stimulate basic growth rates of cells at high and low concentration respectively, determine curvatures of folds and invaginations, tubular, dome-shaped, lenticular, and spherical biological structures. For example, TGF-beta induces endothelial cells and smooth muscle cells to form tubular, vessel-like structures in vitro and blood vessels in vivo. The morphogen modulates cell growth rates via inhibitory and stimulatory receptor pathways respectively, forming a concave curvature as seen from the source concentration end of a radial, vessel-wall diffusion/perfusion driven exponential morphogen concentration gradient. From the source, inhibition declines along the radial gradient, switching to increasing stimulation beyond a neutral point, at which growth inhibition equals growth stimulation. The source concentration, shape of the gradient, and nature of the inhibitory and stimulatory pathways determine mural curvature, independent of mural-cell basic growth rate.
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Affiliation(s)
- E Fosslien
- Department of Pathology, College of Medicine, University of Illinois at Chicago, Chicago, Illionois 60612, USA.
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104
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Yi JY, Hur KC, Lee E, Jin YJ, Arteaga CL, Son YS. TGFbeta1 -mediated epithelial to mesenchymal transition is accompanied by invasion in the SiHa cell line. Eur J Cell Biol 2002; 81:457-68. [PMID: 12234017 DOI: 10.1078/0171-9335-00265] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
It has recently been suggested by several investigators that the epithelial-mesenchymal transition-inducing capacity of TGFbetas contributes to invasive transition of tumors at later stages of carcinogenesis. In the present study, we examined the possibility of TGFbeta1-stimulated epithelial-mesenchymal transition in SiHa cell line, detailed molecular events in the process, and its possible contribution to the invasive transition of tumors. TGFbeta1-induced epithelial-mesenchymal transition of SiHa cells was based on morphological and biochemical criteria; actin stress fiber formation, focal translocalization of integrin alphav, talin, and vinculin, fibronectin-based matrix assembly at the cell periphery, and translocalization and down-regulation of E-cadherin. TGFbeta1 also stimulated surface expression of integrin alphavbeta3 and FAK activation. Focal translocalization of integrin alphav preceded actin reorganization and fibronectin matrix assembly, and functional blocking of the integrin suppressed actin stress fiber formation. Furthermore, induction of actin reorganization and fibronectin matrix assembly by TGFbeta1 were shown to be mutually independent events. These changes were irreversible because 5 minutes pulse exposure to TGFbeta1 was sufficient to stimulate progress of actin reorganization and fibronectin matrix assembly. In further studies with raft culture, TGFbeta1 was found to stimulate invasion of SiHa cells into a type I collagen gel matrix. In conclusion, TGFbeta1 stimulated epithelial-mesenchymal transition of SiHa cells, indicating a positive role in the invasive transition of tumors.
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Affiliation(s)
- Jae Youn Yi
- Laboratory of Tissue Engineering, Korea Cancer Center Hospital, Seoul
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105
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Chamberlain J. Transforming growth factor-beta: a promising target for anti-stenosis therapy. CARDIOVASCULAR DRUG REVIEWS 2002; 19:329-44. [PMID: 11830751 DOI: 10.1111/j.1527-3466.2001.tb00074.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Transforming growth factor-beta (TGF-beta) is the general name for a family of cytokines which have widespread effects on many aspects of growth and development. The TGF-beta isoforms are 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. TGF-beta is involved in the wound healing process and, thus plays a significant role in the formation of a restenotic lesion after percutaneous transluminal coronary angioplasty (PTCA) or stenting. Perhaps because of its wide-ranging effects, TGF-beta is usually released from cells in a latent form, and its activation and signaling are complex. Manipulation of the TGF-beta1, TGF-beta2, and TGF-beta3 isoforms by inhibiting their expression, activation, or signaling reduces scarring and fibrosis in animal models. However, to date, few have reached clinical trial. This review summarizes current knowledge on the activation and signaling of TGF-beta, and focuses on the anti-TGF-beta strategies which may lead to clinical applications in the prevention of restenosis following PTCA or stenting.
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Affiliation(s)
- J Chamberlain
- Cardiovascular Research Group, Section of Medicine, University of Sheffield, Clinical Sciences Centre, Northern General Hospital, Herries Road, Sheffield, S5 7AU, UK.
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106
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Michon IN, Penning LC, Molenaar TJM, van Berkel TJC, Biessen EAL, Kuiper J. The effect of TGF-beta receptor binding peptides on smooth muscle cells. Biochem Biophys Res Commun 2002; 293:1279-86. [PMID: 12054515 DOI: 10.1016/s0006-291x(02)00378-9] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
TGF-beta1 is a potent regulator of vascular smooth muscle cell (VSMC) proliferation, migration, and extracellular matrix (ECM) synthesis. In this study, we selected two peptides, IM-1 and IM-2, that bind to the TGF-beta type II receptor (TGF-beta RII) using phage display. IM-1 and IM-2 bind to the TGF-beta RII, with a K(d) of 1 microM. Like TGF-beta, IM-1 induced VSMC chemotaxis and PAI-1 mRNA expression, as determined using Boyden chambers and real time quantitative PCR. In contrast, IM-2 had no effect on VSMC chemotaxis or PAI-1 induction. Induction of ECM synthesis, involving proteins such as osteopontin and alpha-smooth muscle actin, was determined by ELISA. Osteopontin expression was inhibited by both peptides, but TGF-beta-induced alpha-smooth muscle actin expression could only be inhibited by IM-1. In conclusion, IM-1 activity on VSMC is agonistic with TGF-beta, except for ECM synthesis, whereas the IM-2 peptide is antagonistic for some examined TGF-beta functions.
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Affiliation(s)
- Ingrid N Michon
- Division of Biopharmaceutics, Leiden/Amsterdam Center for Drug Research, Leiden University, P.O. Box 9502, 2300 RA Leiden, The Netherlands.
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107
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Yata Y, Gotwals P, Koteliansky V, Rockey DC. Dose-dependent inhibition of hepatic fibrosis in mice by a TGF-beta soluble receptor: implications for antifibrotic therapy. Hepatology 2002; 35:1022-30. [PMID: 11981752 DOI: 10.1053/jhep.2002.32673] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Transforming growth factor (TGF) beta isoforms (in particular, TGF-beta1) play a central role in the fibrogenic response to injury in many organs, including the liver. Although TGF-beta is clearly important in fibrogenesis, a number of issues related to therapeutic antagonism have emerged. For example, the long-term effect of TGF-beta antagonism is unknown; furthermore, controversy exists as to appropriate levels of TGF-beta inhibition. Therefore, we aimed to examine TGF-beta in models of chronic liver injury and to determine whether an in vivo dose-response relationship exists for inhibition of TGF-beta. Liver injury was induced in BALB/c mice by administering carbon tetrachloride for 4 or 8 weeks. TGF-beta binding was inhibited with a soluble TGF-beta type II receptor (STR) construct, administered intraperitoneally over a dose range of 4.0, 1.0, 0.4, or 0.1 mg/kg twice weekly during fibrogenesis. Fibrogenesis was assessed by measurement of type I collagen messenger RNA (mRNA) expression and by quantitative morphometric analysis. In the 4-week study, STR at concentrations of 4.0, 1.0, and 0.1 mg/kg reduced type I collagen mRNA expression by 31%, 49%, and 60% compared with immunoglobulin (Ig) G controls, respectively. In the 8-week study, lower concentrations of STR (0.1 mg/kg) also had the greatest effect on type I collagen mRNA expression. Quantitative morphometrics similarly showed that lower concentrations of STR were the most antifibrogenic. In conclusion, the results confirm the antifibrotic effect of inhibiting TGF-beta in chronic hepatic wounding and, moreover, show that its in vivo effect in the mouse is dose dependent. Such findings have major translational implications for therapeutic strategies aimed at TGF-beta.
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Affiliation(s)
- Yutaka Yata
- Liver Center and Department of Medicine, Duke University Medical Center, Durham, NC 27710, USA
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108
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Dahlman T, Lammerts E, Bergström D, Franzén A, Westermark K, Heldin NE, Rubin K. Collagen type I expression in experimental anaplastic thyroid carcinoma: regulation and relevance for tumorigenicity. Int J Cancer 2002; 98:186-92. [PMID: 11857406 DOI: 10.1002/ijc.10181] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Fibrosis in solid malignancies plays a significant role in tumor pathophysiology. Potential mechanisms for collagen type I deposition in anaplastic thyroid carcinoma (ATC) were investigated using 6 characterized ATC cell lines. Three of these cell lines, which produced collagen type I, had, as a group, a poor tumorigenicity when inoculated in athymic mice. This group of cells generated tumors in 4 of 24 injected animals (17%). Pro-alpha 1(I) collagen mRNA-expressing carcinoma and stromal cells were interdispersed in the tumors generated by these ATC cells. By contrast, the 3 noncollagen-producing ATC cell lines were all tumorigenic with a tumor take of 60% in the whole group. In the latter tumors, pro-alpha 1(I) collagen mRNA-expressing cells were confined to the stromal compartment, well delineated from carcinoma cell islets. To study the influence of ATC cells on collagen type I synthesis by fibroblasts, we used AG 1518 diploid human fibroblasts cultured on poly-(2-hydroxyethyl methacrylate) (poly[HEMA])-coated plates. This culture condition allows the study of the effect of collagen mRNA translation in the regulation of collagen type I synthesis. Conditioned media from the 6 ATC cell lines did not influence collagen synthesis. The ATC cell line KAT-4 stimulated fibroblast synthesis of collagen type I when the two cell types were cocultured on poly[HEMA]-coated substrates. Specific inhibitors of PDGF and TGF-beta reduced the KAT 4 carcinoma cell-induced stimulation of collagen type I synthesis. Our data suggest that collagen type I production by carcinoma cells correlates negatively with tumorigenicity and that the formation of a well-defined stroma is of importance for tumor growth. Furthermore, our data suggest that tumor cells are able to stimulate collagen mRNA translation in stromal fibroblasts in direct cell-cell contact by, at least in part, transferring PDGF or TGF-beta.
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Affiliation(s)
- Thèrése Dahlman
- Department of Medical Biochemistry and Microbiology, Biomedical Center, Uppsala, Sweden
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109
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Sheppard D. Roger S. Mitchell lecture. Uses of expression microarrays in studies of pulmonary fibrosis, asthma, acute lung injury, and emphysema. Chest 2002; 121:21S-25S. [PMID: 11893658 DOI: 10.1378/chest.121.3_suppl.21s-a] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Expression microarrays are a powerful tool that could provide new information about the molecular pathways regulating common lung diseases. To exemplify how this tool can be useful, selected examples of informative experiments are reviewed. In studies relevant to asthma, the cytokine interleukin-13 has been shown to produce many of the phenotypic features of this disease, but the cellular targets in the airways and the molecular pathways activated are largely unknown. We have used microarrays to begin to dissect the different transcriptional responses of primary lung cells to this cytokine. In experiments designed to identify global transcriptional programs responsible for regulating lung inflammation and pulmonary fibrosis, we performed microarray experiments on lung tissue from wild-type mice and mice lacking a member of the integrin family know to be involved in activation of latent transforming growth factor (TGF)-beta. In addition to identifying distinct cluster of genes involved in each of these processes, these studies led to the identification of novel pathways by which TGF-beta can regulate acute lung injury and emphysema. Together, these examples demonstrate how careful application and thorough analysis of expression microarrays can facilitate the discovery of novel molecular targets for intervening in common lung diseases.
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Affiliation(s)
- Dean Sheppard
- Lung Biology Center, Center for Occupational and Environmental Health, Cardiovascular Research Institute, Department of Medicine, University of California, San Francisco, San Francisco, CA 94143, USA.
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110
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Gotohda T, Tokunaga I, Kubo SI, Kitamura O, Ishigami A. Toluene inhalation induces glial cell line-derived neurotrophic factor, transforming growth factor and tumor necrosis factor in rat cerebellum. Leg Med (Tokyo) 2002; 4:21-8. [PMID: 12935687 DOI: 10.1016/s1344-6223(01)00058-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Rats were exposed to toluene (1500 ppm for 4 h per day) for 7 days. After toluene inhalation, only granule cells in the dentate gyrus of the hippocampus were slightly shrunken. In the cerebellum, several Purkinje cells were shrunken and lost, and the white matter was thinner than in controls. Microtubule-associated protein 2 (MAP2)-immunopositive filaments of neuronal processes were slightly disarrayed in the radial layer of the hippocampus, and were fragmented in the molecular layer of the cerebellum. It was considered that toluene induced neuronal changes both in the cerebellum and the hippocampus. To elucidate the effect of neurotrophic factors on those neuronal changes, glial cell line-derived neurotrophic factor (GDNF), transforming growth factor (TGF) and tumor necrosis factor (TNF) in rat brain were examined immunohistochemically. In control rats, TNF-alpha was not stained in either the hippocampus or the cerebellum, while TGF-beta1 was scarcely expressed in the cerebellum. GDNF was minimally expressed in the Purkinje cells in the cerebellum. After toluene-treatment, TGF-beta1 was over-expressed in the endothelium of the capillary vessel walls in both regions. In the cerebellum, TNF-alpha was induced only in the granule cells, while GDNF expression was enhanced in the Purkinje cells. These data suggest that toluene induces astrocyte activation through TGF-beta1 upregulation, which then induces GDNF in the Purkinje cells and TNF-alpha in the granule cells of the cerebellum. The differences in the expression of the neurotrophic factors may account for neurobehavioral changes after toluene exposure.
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Affiliation(s)
- Takako Gotohda
- Department of Legal Medicine, School of Medicine, The University of Tokushima, Japan
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111
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Bing OHL, Conrad CH, Boluyt MO, Robinson KG, Brooks WW. Studies of prevention, treatment and mechanisms of heart failure in the aging spontaneously hypertensive rat. Heart Fail Rev 2002; 7:71-88. [PMID: 11790924 DOI: 10.1023/a:1013753907135] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The spontaneously hypertensive rat (SHR) is an animal model of genetic hypertension which develops heart failure with aging, similar to man. The consistent pattern of a long period of stable hypertrophy followed by a transition to failure provides a useful model to study mechanisms of heart failure with aging and test treatments at differing phases of the disease process. The transition from compensated hypertrophy to failure is accompanied by changes in cardiac function which are associated with altered active and passive mechanical properties of myocardial tissue; these events define the physiologic basis for cardiac decompensation. In examining the mechanism for myocardial tissue dysfunction, studies have demonstrated a central role for neurohormonal activation, and specifically the renin-angiotensin-aldosterone system. Pharmacologic attenuation of this system at differing points in the course of the process suggests that prevention but not reversal of myocardial tissue dysfunction is possible. The roles of the extracellular matrix, apoptosis, intracellular calcium, beta-adrenergic stimulation, microtubules, and oxygen supply-demand relationships in ultimately mediating myocardial tissue dysfunction are reviewed. Studies suggest that while considerable progress has been made in understanding and treating the transition to failure, our current state of knowledge is limited in scope and we are not yet able to define specific mechanisms responsible for tissue dysfunction. It will be necessary to integrate information on the roles of newly discovered, and as yet undiscovered, genes and pathways to provide a clearer understanding of maladaptive remodeling seen with heart failure. Understanding the mechanism for tissue dysfunction is likely to result in more effective treatments for the prevention and reversal of heart failure with aging. It is anticipated that the SHR model will assist us in reaching these important goals.
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Affiliation(s)
- Oscar H L Bing
- The Department of Medicine, VA Boston Healthcare System, 150 South Huntington Avenue, Boston, MA 02130, USA.
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112
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Plekhanova O, Parfyonova Y, Bibilashvily R, Domogatskii S, Stepanova V, Gulba DC, Agrotis A, Bobik A, Tkachuk V. Urokinase plasminogen activator augments cell proliferation and neointima formation in injured arteries via proteolytic mechanisms. Atherosclerosis 2001; 159:297-306. [PMID: 11730809 DOI: 10.1016/s0021-9150(01)00511-1] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Urokinase plasminogen activator (uPA) has been implicated in the healing responses of injured arteries, but the importance of its various properties that influence smooth muscle cell (SMC) proliferation and migration in vivo is unclear. We used three recombinant (r-) forms of uPA, which differ markedly in their proteolytic activities and abilities to bind to the uPA receptor (uPAR), to determine, which property most influences the healing responses of balloon catheter injured rat carotid arteries. After injury, uPA and uPAR expression increased markedly throughout the period when medial SMCs were rapidly proliferating and migrating to form the neointima. Perivascular application of uPA neutralizing antibodies immediately after injury attenuated the healing response, significantly reducing neointima size and neointimal SMC numbers. Perivascular application of r-uPAwt (wild type uPA) or r-uPA/GDF (r-uPA with multiple mutations in its growth factor-like domain) doubled the size of the neointima. Four days after injury these two uPAs nearly doubled neointimal and medial SMC numbers in the vessels, and induced greater reductions in lumen size than injury alone. Proteolytically inactive r-uPA/H/Q (containing glutamine rather than histidine-204 in its catalytic site) did not affect neointima or lumen size. Also, in contrast to the actions of proteolytically active uPAs, tissue plasminogen activator (tPA) did not affect the rate of neointima development. We conclude that uPA is an important factor regulating the healing responses of balloon catheter injured arteries, and its proteolytic property, which cannot be mimicked by tPA, greatly influences SMC proliferation and early neointima formation.
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Affiliation(s)
- O Plekhanova
- Molecular Endocrinology Laboratory, Institute of Experimental Cardiology, Cardiology Research Center, 121552, Moscow, Russia
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113
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Akman HO, Zhang H, Siddiqui MA, Solomon W, Smith EL, Batuman OA. Response to hypoxia involves transforming growth factor-beta2 and Smad proteins in human endothelial cells. Blood 2001; 98:3324-31. [PMID: 11719370 DOI: 10.1182/blood.v98.12.3324] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Oxygen deprivation (hypoxia) is a consistent component of ischemia that induces an inflammatory and prothrombotic response in the endothelium. In this report, it is demonstrated that exposure of endothelial cells to hypoxia (1% O(2)) increases messenger RNA and protein levels of transforming growth factor-beta2 (TGF-beta2), a cytokine with potent regulatory effects on vascular inflammatory responses. Messenger RNA levels of the TGF-beta2 type II membrane receptor, which is a serine threonine kinase, also increased. The stimulatory effect of hypoxia was found to occur at the level of transcription of the TGF-beta2 gene and involves Smad proteins, a class of intracellular signaling proteins that mediates the downstream effects of TGF-beta receptors. Transient transfection studies showed that the region spanning -77 and -40 base pairs within the TGF-beta2 promoter (harboring a Smad-binding "CAGA box") is activated in hypoxic cells compared with nonhypoxic controls (P <.01). Hypoxia also stimulated transcription from another promoter, 3TP-Lux, a reporter construct responsive to Smads and TGF-beta. In addition, specific binding to a Smad-binding oligonucleotide was observed with nuclear extracts from hypoxic endothelial cells but not from nonhypoxic cells. It is concluded that Smad proteins, which can regulate endothelial responses to mechanical and inflammatory stress, also may play an important role in vascular responses to hypoxia and ischemia.
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Affiliation(s)
- H O Akman
- Division of Hematology/Oncology, Department of Medicine, Center for Cardiovascular and Molecular Medicine, State University of New York Downstate Medical Center, Brooklyn, NY 11203, USA
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114
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Ensenat D, Hassan S, Reyna SV, Schafer AI, Durante W. Transforming growth factor-beta 1 stimulates vascular smooth muscle cell L-proline transport by inducing system A amino acid transporter 2 (SAT2) gene expression. Biochem J 2001; 360:507-12. [PMID: 11716780 PMCID: PMC1222252 DOI: 10.1042/0264-6021:3600507] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Transforming growth factor-beta1 (TGF-beta 1) is a multifunctional cytokine that contributes to arterial remodelling by stimulating vascular smooth muscle cell (SMC) growth and collagen synthesis at sites of vascular injury. Since l-proline is essential for the synthesis of collagen, we examined whether TGF-beta 1 regulates the transcellular transport of l-proline by vascular SMCs. l-Proline uptake by vascular SMCs was primarily sodium-dependent, pH-sensitive, blocked by neutral amino acids and alpha-(methylamino)isobutyric acid, and exhibited trans-inhibition. Treatment of SMCs with TGF-beta 1 stimulated l-proline transport in a concentration- and time-dependent manner. The TGF-beta 1-mediated l-proline uptake was inhibited by cycloheximide or actinomycin D. Kinetic studies indicated that TGF-beta 1-induced l-proline transport was mediated by an increase in transport capacity independent of any changes in the affinity for l-proline. TGF-beta 1 stimulated the expression of system A amino acid transporter 2 (SAT2) mRNA in a time-dependent fashion that paralleled the increase in l-proline transport. Reverse transcriptase PCR failed to detect the presence of SAT1 or amino acid transporter 3 (ATA3) in either untreated or TGF-beta 1-treated SMCs. These results demonstrate that l-proline transport by vascular SMCs is mediated predominantly by the SAT and that TGF-beta 1 stimulates SMC l-proline uptake by inducing the expression of the SAT2 gene. The ability of TGF-beta 1 to induce SAT2 expression may function to provide SMCs with the necessary levels of l-proline required for collagen synthesis and cell growth.
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MESH Headings
- Amino Acid Transport System A/analysis
- Amino Acid Transport System A/biosynthesis
- Amino Acid Transport System A/genetics
- Animals
- Biological Transport, Active/genetics
- Cells, Cultured
- DNA, Complementary/analysis
- Dose-Response Relationship, Drug
- Gene Expression Regulation/physiology
- Kinetics
- Muscle, Smooth, Vascular/chemistry
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/metabolism
- Proline/metabolism
- Rats
- Reverse Transcriptase Polymerase Chain Reaction
- Substrate Specificity/genetics
- Transforming Growth Factor beta/pharmacology
- Transforming Growth Factor beta/physiology
- Transforming Growth Factor beta1
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Affiliation(s)
- D Ensenat
- Houston VA Medical Center, Building 109, Room 130, 2002 Holcombe Blvd, Houston, TX 77030, USA
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115
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Wilcox JN, Okamoto EI, Nakahara KI, Vinten-Johansen J. Perivascular responses after angioplasty which may contribute to postangioplasty restenosis: a role for circulating myofibroblast precursors? Ann N Y Acad Sci 2001; 947:68-90; dicussion 90-2. [PMID: 11795311 DOI: 10.1111/j.1749-6632.2001.tb03931.x] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
These studies suggest that the adventitia may play a role in vascular lesion formation after balloon overstretch injury of pig coronary arteries by contributing to the cellular mass of the neointima and the synthesis of growth factors. In addition, the adventitia may contribute to vascular remodeling and constriction of the external elastic lamina through accumulation of myofibroblasts containing alpha smooth muscle actin in the adventitia surrounding the injury site. Inhibition of myofibroblast proliferation and/or recruitment by intravascular brachytherapy positively affects vascular remodeling through its action on adventitial cells. Inflammation is a major event associated with balloon angioplasty, resulting in the sequential recruitment of neutrophils (2-24 hours) and monocyte/macrophages (24-72 hours) predominantly into the adventitia surrounding the injury site. It is hypothesized that inflammatory cells release cytokines and/or increase the production of superoxides which stimulate the proliferation and recruitment of adventitial myofibroblasts. Inflammatory and proliferative responses were not confined to the local adventitia but were found extending as far as 1-3 mm away from the injured vessel in the distal perivascular tissues. Studies were performed to examine the expression of genes associated with cell migration at early times after injury in an attempt to determine the source of the adventitial myofibroblasts. Expression of genes involved in cell migration including MMP-2, MMP-9, and tenascin was found as early as 2 hours following angioplasty in the intramyocardial, pericardial, and adipose tissue fibroblasts. While these studies suggest that local tissue was the source of the myofibroblasts recruited to the injury site, we have been unable to confirm this finding by direct fluorescent labeling of adventitial cells. Recent work from our laboratory suggests that myofibroblast precursors may be isolated from buffy coat preparations from peripheral blood. These results lead us to hypothesize that stem cells that differentiate into myofibroblasts may be recruited in early inflammatory infiltrates in the adventitia. Clearly, additional work will have to be directed at a more detailed examination of the response of adventitial and other perivascular cells and tissues to balloon injury to determine their sources and their role in regulating vascular lesion development.
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Affiliation(s)
- J N Wilcox
- Emory University School of Medicine, The Winship Cancer Institute, Division of Hematology/Oncology, Atlanta, Georgia 30322, USA.
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116
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Cottin Y, Kollum M, Kolodgie FD, Chan RC, Kim HS, Vodovotz Y, Virmani R, Waksman R, Yazdi H. Intravascular radiation accelerates atherosclerotic lesion formation of hypercholesteremic rabbits. CARDIOVASCULAR RADIATION MEDICINE 2001; 2:231-40. [PMID: 12160765 DOI: 10.1016/s1522-1865(02)00129-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVES The purpose of the present study is to evaluate the effect of intravascular radiation (IR) on the arterial wall of uninjured vessels in the hypercholesteremic rabbit model. METHODS Aortas of 24 New Zealand white rabbits were treated with either intravascular 192-Ir gamma-radiation (15 Gy at 2 mm from the center of the source) or were exposed to the source catheter without radiation (sham controls). Following the radiation treatment, the animals were fed a 2% cholesterol diet until euthanasia at 2 (n=8) or 6 (n=16) weeks. Arteries were analyzed using light and scanning electron microscopy (SEM); transforming growth factor beta (TGF-beta) 1, a promoter of connective tissue deposition, was also monitored. RESULTS At 2 weeks, SEM analysis showed well-aligned endothelial cells in nonradiated segments, whereas irradiated arteries consistently contained adherent and subendothelial macrophages with focal areas of endothelial disruption. Further radiated segments at 2 weeks showed a 7-fold increase in active TGF beta-1 over nonradiated segments. At 6 weeks, there was a significant increase in plaque and vessel wall area relative to control arteries, however, no differences were noted in the density of actin-positive smooth muscle cells (SMCs) or macrophages. Similarly, no differences were noted in cell proliferation between groups as evidenced by the marker bromodeoxyuridine (BrdU). In contrast, nonirradiated segments frequently contained cellular areas with extracellular lipid. CONCLUSION Exposure of previously uninjured vessels to IR and hypercholesterolemia is associated with increased plaque burden and leads to more advanced plaque types. Special care should be taken to minimize radiation exposure in normal vascular segments in hypercholesterolemic patients undergoing radiation therapy.
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Affiliation(s)
- Y Cottin
- Medstar Research Institute, Washington Hospital Center, Washington, DC 20010, USA
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117
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Paranya G, Vineberg S, Dvorin E, Kaushal S, Roth SJ, Rabkin E, Schoen FJ, Bischoff J. Aortic valve endothelial cells undergo transforming growth factor-beta-mediated and non-transforming growth factor-beta-mediated transdifferentiation in vitro. THE AMERICAN JOURNAL OF PATHOLOGY 2001; 159:1335-43. [PMID: 11583961 PMCID: PMC1850524 DOI: 10.1016/s0002-9440(10)62520-5] [Citation(s) in RCA: 161] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Cardiac valves arise from endocardial cushions, specialized regions of the developing heart that are formed by an endothelial-to-mesenchymal cell transdifferentiation. Whether and to what extent this transdifferentiation is retained in mature heart valves is unknown. Herein we show that endothelial cells from mature valves can transdifferentiate to a mesenchymal phenotype. Using induction of alpha-smooth muscle actin (alpha-SMA), an established marker for this process, two distinct pathways of transdifferentiation were identified in clonally derived endothelial cell populations isolated from ovine aortic valve leaflets. alpha-SMA expression was induced by culturing clonal endothelial cells in medium containing either transforming growth factor-beta or low levels of serum and no basic fibroblast growth factor. Cells induced to express alpha-SMA exhibited markedly increased migration in response to platelet-derived growth factor-BB, consistent with a mesenchymal phenotype. A population of the differentiated cells co-expressed CD31, an endothelial marker, along with alpha-SMA, as seen by double-label immunofluorescence. Similarly, this co-expression of endothelial markers and alpha-SMA was detected in a subpopulation of cells in frozen sections of aortic valves, suggesting the transdifferentiation may occur in vivo. Hence, the clonal populations of valvular endothelial cells described here provide a powerful in vitro model for dissecting molecular events that regulate valvular endothelium.
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Affiliation(s)
- G Paranya
- Department of Surgery, Children's Hospital, Boston, Massachusetts 02115, USA
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118
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Lee CG, Homer RJ, Zhu Z, Lanone S, Wang X, Koteliansky V, Shipley JM, Gotwals P, Noble P, Chen Q, Senior RM, Elias JA. Interleukin-13 induces tissue fibrosis by selectively stimulating and activating transforming growth factor beta(1). J Exp Med 2001; 194:809-21. [PMID: 11560996 PMCID: PMC2195954 DOI: 10.1084/jem.194.6.809] [Citation(s) in RCA: 703] [Impact Index Per Article: 30.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Interleukin (IL)-13 is a key mediator of tissue fibrosis caused by T helper cell type 2 inflammation. We hypothesized that the fibrogenic effects of IL-13 are mediated by transforming growth factor (TGF)-beta. To test this hypothesis we compared the regulation of TGF-beta in lungs from wild-type mice and CC10-IL-13 mice in which IL-13 overexpression causes pulmonary fibrosis. IL-13 selectively stimulated TGF-beta(1) production in transgenic animals and macrophages were the major site of TGF-beta(1) production and deposition in these tissues. IL-13 also activated TGF-beta(1) in vivo. This activation was associated with decreased levels of mRNA encoding latent TGF-beta-binding protein-1 and increased mRNA encoding urinary plasminogen activator, matrix metalloproteinase (MMP)-9, and CD44. TGF-beta(1) activation was abrogated by the plasmin/serine protease antagonist aprotinin. It was also decreased in progeny of crosses of CC10-IL-13 mice and MMP-9 null mice but was not altered in crosses with CD44 null animals. IL-13-induced fibrosis was also significantly ameliorated by treatment with the TGF-beta antagonist soluble TGFbetaR-Fc (sTGFbetaR-Fc). These studies demonstrate that IL-13 is a potent stimulator and activator of TGF-beta(1) in vivo. They also demonstrate that this activation is mediated by a plasmin/serine protease- and MMP-9-dependent and CD44-independent mechanism(s) and that the fibrogenic effects of IL-13 are mediated, in great extent, by this TGF-beta pathway.
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Affiliation(s)
- Chun Geun Lee
- Yale University School of Medicine, Section of Pulmonary and Critical Care Medicine, Department of Internal Medicine
| | - Robert J. Homer
- Department of Pathology, New Haven, CT 06520
- Pathology and Laboratory Medicine Service, VA-CT Health Care System, West Haven, CT 06516
| | - Zhou Zhu
- Yale University School of Medicine, Section of Pulmonary and Critical Care Medicine, Department of Internal Medicine
| | - Sophie Lanone
- Yale University School of Medicine, Section of Pulmonary and Critical Care Medicine, Department of Internal Medicine
| | - Xiaoman Wang
- Yale University School of Medicine, Section of Pulmonary and Critical Care Medicine, Department of Internal Medicine
| | | | - J. Michael Shipley
- Washington University School of Medicine, Section of Pulmonary and Critical Care Medicine, Barnes-Jewish Hospital, St. Louis, MO 63110
| | | | - Paul Noble
- Yale University School of Medicine, Section of Pulmonary and Critical Care Medicine, Department of Internal Medicine
| | - Qingsheng Chen
- Yale University School of Medicine, Section of Pulmonary and Critical Care Medicine, Department of Internal Medicine
| | - Robert M. Senior
- Washington University School of Medicine, Section of Pulmonary and Critical Care Medicine, Barnes-Jewish Hospital, St. Louis, MO 63110
| | - Jack A. Elias
- Yale University School of Medicine, Section of Pulmonary and Critical Care Medicine, Department of Internal Medicine
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119
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Tomanek RJ, Zheng W, Peters KG, Lin P, Holifield JS, Suvarna PR. Multiple growth factors regulate coronary embryonic vasculogenesis. Dev Dyn 2001; 221:265-73. [PMID: 11458387 DOI: 10.1002/dvdy.1137] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Mechanisms regulating coronary vascularization are not well understood. To test hypotheses regarding the influence of key growth factors and their interactions, we studied vascular tube formation (vasculogenesis) in collagen gels onto which quail embryonic ventricles were placed and incubated in the presence of growth factors or inhibitors. Vasculogenesis in this model is dependent on tyrosine kinase receptors, since tube formation was totally blocked by genestein. Tube formation was attenuated when anti-bFGF or anti-VEGF neutralizing antibodies were added to the medium and nearly completely inhibited when the both were added. The attenuation associated with anti-VEGF was due primarily to a decrease in assembly of endothelial cells, while that associated with bFGF was primarily due to a reduction in endothelial cells. Soluble tie-2, the receptor for angiopoietins, also had an inhibitory effect and, when added with either anti-bFGF or anti-VEGF, markedly attenuated tube formation. At optimal doses, tube formation was enhanced 6.5-fold by bFGF and 2.5-fold by VEGF over the controls. Each of these growth factors was dependent upon the other for optimal induction of tube formation, since neutralizing antibodies to one markedly reduced the potency of the other. VEGF potency was also markedly reduced when soluble tie-2 was added to the medium. Tube formation was virtually totally blocked by exogenous TGF-beta at doses > 1 ng/ml, while neutralizing TGF-beta antibodies enhanced tube formation 2-fold in the 30 ng-30 microg range. These data provide the first documentation of multiple growth factor regulation of coronary tube formation.
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Affiliation(s)
- R J Tomanek
- Department of Anatomy and Cell Biology, and The Cardiovascular Center, University of Iowa, Iowa City, Iowa 52242, USA.
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120
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Pittet JF, Griffiths MJ, Geiser T, Kaminski N, Dalton SL, Huang X, Brown LA, Gotwals PJ, Koteliansky VE, Matthay MA, Sheppard D. TGF-beta is a critical mediator of acute lung injury. J Clin Invest 2001; 107:1537-44. [PMID: 11413161 PMCID: PMC200192 DOI: 10.1172/jci11963] [Citation(s) in RCA: 380] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
We have shown that the integrin alphavbeta6 activates latent TGF-beta in the lungs and skin. We show here that mice lacking this integrin are completely protected from pulmonary edema in a model of bleomycin-induced acute lung injury (ALI). Pharmacologic inhibition of TGF-beta also protected wild-type mice from pulmonary edema induced by bleomycin or Escherichia coli endotoxin. TGF-beta directly increased alveolar epithelial permeability in vitro by a mechanism that involved depletion of intracellular glutathione. These data suggest that integrin-mediated local activation of TGF-beta is critical to the development of pulmonary edema in ALI and that blocking TGF-beta or its activation could be effective treatments for this currently untreatable disorder.
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Affiliation(s)
- J F Pittet
- Departments of Anesthesia and Surgery, University of California San Francisco, San Francisco, California 94110, USA
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121
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Stock UA, Wiederschain D, Kilroy SM, Shum-Tim D, Khalil PN, Vacanti JP, Mayer JE, Moses MA. Dynamics of extracellular matrix production and turnover in tissue engineered cardiovascular structures. J Cell Biochem 2001; 81:220-8. [PMID: 11241662 DOI: 10.1002/1097-4644(20010501)81:2<220::aid-jcb1037>3.0.co;2-o] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Appropriate matrix formation, turnover and remodeling in tissue-engineered small diameter vascular conduits are crucial requirements for their long-term patency and function. This complex process requires the deposition and accumulation of extracellular matrix molecules as well as the remodeling of this extracellular matrix (ECM) by matrix metalloproteinases (MMPs) and their endogenous inhibitors (TIMPs). In this study, we have investigated the dynamics of ECM production and the activity of MMPs and TIMPs in long-term tissue-engineered vascular conduits using quantitative ECM analysis, substrate gel electrophoresis, radiometric enzyme assays and Western blot analyses. Over a time period of 169 days in vivo, levels of elastin and proteoglycans/glycosaminoglycans in tissue-engineered constructs came to approximate those of their native tissue counter parts. The kinetics of collagen deposition and remodeling, however, apparently require a much longer time period. Through the use of substrate gel electrophoresis, proteolytic bands whose molecular weight was consistent with their identification as the active form of MMP-2 (approximately 64--66 kDa) were detected in all native and tissue-engineered samples. Additional proteolytic bands migrating at approximately 72 kDa representing the latent form of MMP-2 were detected in tissue-engineered samples at time points from 5 throughout 55 days. Radiometric assays of MMP-1 activity demonstrated no significant differences between the native and tissue-engineered samples. This study determines the dynamics of ECM production and turnover in a long-term tissue-engineered vascular tissue and highlights the importance of ECM remodeling in the development of successful tissue-engineered vascular structures.
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Affiliation(s)
- U A Stock
- Department of Cardiovascular Surgery, Children's Hospital, Harvard Medical School, Boston, MA, USA.
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122
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Batuman O, Go D, Clark LT, Smith EL, Clements P, Feit A, Lederer D. Relationship between cytokine levels and coronary artery disease in women. HEART DISEASE (HAGERSTOWN, MD.) 2001; 3:80-4. [PMID: 11975775 DOI: 10.1097/00132580-200103000-00004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Inflammation is thought to have a role in the pathogenesis of atherosclerotic coronary artery disease (CAD), and the measurement of markers of inflammation has been suggested to improve the identification of individuals at risk for this disease. The incidence of CAD in women is not accounted for by conventional risk factors, and the association of CAD and the antiinflammatory cytokine transforming growth factor beta1 (TGF-beta1) in this population is unknown. Associations among TGF-beta1, the inflammatory cytokine tumor necrosis factor alpha (TNF-alpha), and CAD severity in inner city women were examined. Fifty-three women requiring angiography (mean age, 60.7 years) were stratified as having on of the following conditions: 0 vessel disease (VD) (n = 20), 1 (VD) (n = 10), 2 VD (n = 9), or 3 VD (n = 14). Fasting serum cytokine levels were determined by enzyme-linked immunosorbent assay. Serum TGF-beta1 was lower in patients with extensive disease (2 and 3 VD versus 0 and 1 VD). The lowest TGF-beta1 levels (<30 ng/mL) were in the 2 and 3 VD groups. In contrast, in the 0 and 1 VD groups, TGF-beta1 was above 41 ng/mL. Serum TGF-beta1 correctly classified the severity of CAD in 62.3% of patients, with a predictive threshold of 58 ng/mL by discriminant function analysis. TGF-beta1 may be a determinant of clinical events and outcome in CAD in women.
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Affiliation(s)
- O Batuman
- Division of Hematology, Department of Medicine, State University of New York Health Science Center at Brooklyn 11203, USA.
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123
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Friedman SL, Maher JJ, Bissell DM. Mechanisms and therapy of hepatic fibrosis: report of the AASLD Single Topic Basic Research Conference. Hepatology 2000; 32:1403-8. [PMID: 11093750 DOI: 10.1053/jhep.2000.20243] [Citation(s) in RCA: 114] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- S L Friedman
- Division of Liver Diseases and Dept of Medicine, Mount Sinai School of Medicine, New York, NY 10029, USA.
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124
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Douillet CD, Velarde V, Christopher JT, Mayfield RK, Trojanowska ME, Jaffa AA. Mechanisms by which bradykinin promotes fibrosis in vascular smooth muscle cells: role of TGF-beta and MAPK. Am J Physiol Heart Circ Physiol 2000; 279:H2829-37. [PMID: 11087238 DOI: 10.1152/ajpheart.2000.279.6.h2829] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Accumulation of extracellular matrix (ECM) is a hallmark feature of vascular disease. We have previously shown that hyperglycemia induces the expression of B(2)-kinin receptors in vascular smooth muscle cells (VSMC) and that bradykinin (BK) and hyperglycemia synergize to stimulate ECM production. The present study examined the cellular mechanisms through which BK contributes to VSMC fibrosis. VSMC treated with BK (10(-8) M) for 24 h significantly increased alpha(2)(I) collagen mRNA levels. In addition, BK produced a two- to threefold increase in alpha(2)(I) collagen promoter activity in VSMC transfected with a plasmid containing the alpha(2)(I) collagen promoter. Furthermore, treatment of VSMC with BK for 24 h produced a two- to threefold increase in the secretion rate of tissue inhibitor of metalloproteinase 1 (TIMP-1). The increase in alpha(2)(I) collagen mRNA levels and alpha(2)(I) collagen promoter activity, as well as TIMP-1 secretion, in response to BK were blocked by anti-transforming growth factor-beta (anti-TGF-beta) neutralizing antibodies. BK (10(-8) M) increased the endogenous production of TGF-beta1 mRNA and protein levels. Inhibition of the mitogen-activated protein kinase (MAPK) pathway by PD-98059 inhibited the increase of alpha(2)(I) collagen promoter activity, TIMP-1 production, and TGF-beta1 protein levels observed in response to BK. These findings provide the first evidence that BK induces collagen type I and TIMP-1 production via autocrine activation of TGF-beta1 and implicate MAPK pathway as a key player in VSMC fibrosis in response of BK.
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Affiliation(s)
- C D Douillet
- Department of Medicine, Medical University of South Carolina, Charleston, USA
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125
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Cosgrove D, Rodgers K, Meehan D, Miller C, Bovard K, Gilroy A, Gardner H, Kotelianski V, Gotwals P, Amatucci A, Kalluri R. Integrin alpha1beta1 and transforming growth factor-beta1 play distinct roles in alport glomerular pathogenesis and serve as dual targets for metabolic therapy. THE AMERICAN JOURNAL OF PATHOLOGY 2000; 157:1649-59. [PMID: 11073824 PMCID: PMC1885718 DOI: 10.1016/s0002-9440(10)64802-x] [Citation(s) in RCA: 142] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Alport syndrome is a genetic disorder resulting from mutations in type IV collagen genes. The defect results in pathological changes in kidney glomerular and inner-ear basement membranes. In the kidney, progressive glomerulonephritis culminates in tubulointerstitial fibrosis and death. Using gene knockout-mouse models, we demonstrate that two different pathways, one mediated by transforming growth factor (TGF)-beta1 and the other by integrin alpha1beta1, affect Alport glomerular pathogenesis in distinct ways. In Alport mice that are also null for integrin alpha1 expression, expansion of the mesangial matrix and podocyte foot process effacement are attenuated. The novel observation of nonnative laminin isoforms (laminin-2 and/or laminin-4) accumulating in the glomerular basement membrane of Alport mice is markedly reduced in the double knockouts. The second pathway, mediated by TGF-beta1, was blocked using a soluble fusion protein comprising the extracellular domain of the TGF-beta1 type II receptor. This inhibitor prevents focal thickening of the glomerular basement membrane, but does not prevent effacement of the podocyte foot processes. If both integrin alpha1beta1 and TGF-beta1 pathways are functionally inhibited, glomerular foot process and glomerular basement membrane morphology are primarily restored and renal function is markedly improved. These data suggest that integrin alpha1beta1 and TGF-beta1 may provide useful targets for a dual therapy aimed at slowing disease progression in Alport glomerulonephritis.
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Affiliation(s)
- D Cosgrove
- Department of Genetics, Boys Town National Research Hospital, Omaha, Nebraska, USA.
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126
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Zheng H, Wang J, Koteliansky VE, Gotwals PJ, Hauer-Jensen M. Recombinant soluble transforming growth factor beta type II receptor ameliorates radiation enteropathy in mice. Gastroenterology 2000; 119:1286-96. [PMID: 11054386 DOI: 10.1053/gast.2000.19282] [Citation(s) in RCA: 94] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
BACKGROUND & AIMS Transforming growth factor (TGF)-beta has been implicated in many fibrotic conditions. However, its mechanistic role in radiation toxicity is equivocal despite compelling correlative evidence. This study assessed whether in vivo administration of a soluble TGF-beta type II receptor (TbetaR-II) protein ameliorates intestinal radiation injury (radiation enteropathy). METHODS A recombinant fusion protein, consisting of the extracellular portion of mouse TbetaR-II and the Fc portion of mouse immunoglobulin (Ig) G, was produced. A 5-cm segment of mouse ileum was exposed to 19 Gy x-radiation. TbetaR-II:Fc fusion protein (1 mg/kg every other day) or mouse IgG was administered from 2 days before to 6 weeks after irradiation. Radiation injury was assessed at 6 weeks using quantitative histology, morphometry, and immunohistochemistry. Collagen was measured colorimetrically, and TGF-beta1 messenger RNA was assessed with fluorogenic probe reverse-transcription polymerase chain reaction. RESULTS Compared with IgG controls, TbetaR-II:Fc-treated mice exhibited less structural injury, preservation of mucosal surface area, and less intestinal wall fibrosis. Intestinal TGF-beta1 messenger RNA increased in TbetaR-II:Fc-treated mice, whereas TGF-beta immunoreactivity decreased. TbetaR-II:Fc treatment increased crypt cell proliferation but otherwise did not affect unirradiated intestine. CONCLUSIONS Long-term modulation of TGF-beta with a TbetaR-II:Fc fusion protein is feasible and ameliorates radiation enteropathy. These data confirm the putative role of TGF-beta in intestinal radiation fibrosis.
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Affiliation(s)
- H Zheng
- Departments of Surgery and Pathology, University of Arkansas for Medical Sciences and Central Arkansas Veterans Healthcare System, Little Rock, Arkansas 72205, USA
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127
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Sajid M, Lele M, Stouffer GA. Autocrine thrombospondin partially mediates TGF-beta1- induced proliferation of vascular smooth muscle cells. Am J Physiol Heart Circ Physiol 2000; 279:H2159-65. [PMID: 11045949 DOI: 10.1152/ajpheart.2000.279.5.h2159] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Transforming growth factor (TGF)-beta1 has been implicated in vascular healing responses after mechanical injury. Using cultured rat aortic smooth muscle cells (RASMC), we examined the hypothesis that production and secretion of thrombospondin (TSP) contributes to TGF-beta1-induced proliferation. We found that TGF-beta1 enhanced production and secretion of TSP, with peak levels of secreted TSP observed 24 h after treatment. RASMC treated with TGF-beta1 secreted a mitogenic activity that was transferable in conditioned media and partially inhibited by C6.7, a monoclonal anti-TSP antibody. Exogenous TSP stimulated a proliferative response, with maximal [(3)H]thymidine incorporation occurring 24 h earlier than maximal [(3)H]thymidine incorporation in response to TGF-beta1-treatment. Pretreatment with C6.7 or polyclonal anti-TSP neutralizing antibodies inhibited TGF-beta1-induced proliferation of RASMC. Proliferative responses to TGF-beta1 were also inhibited by pretreatment with an anti-beta(3) integrin monoclonal blocking antibody (F11), RGD peptides, and the anti-alpha(v)beta(3) disintegrin echistatin. Treatment with TSP and TGF-beta1 increased c-Jun NH(2)-terminal kinase (JNK)1 activity, with peak effects observed at 15 min and 4 h, respectively. Treatment with C6.7 or F11 inhibited TGF-beta-induced activation of JNK1. In summary, these studies support the hypothesis that TGF-beta-induced JNK1 activation and proliferation of RASMC require secretion of TSP and ligation of alpha(v)beta(3)-integrins.
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MESH Headings
- Animals
- Antibodies, Blocking/pharmacology
- Autocrine Communication/drug effects
- Autocrine Communication/physiology
- Cell Division/drug effects
- Cells, Cultured
- Culture Media, Conditioned/metabolism
- Culture Media, Conditioned/pharmacology
- Mitogen-Activated Protein Kinase 8
- Mitogen-Activated Protein Kinases/metabolism
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Rats
- Rats, Sprague-Dawley
- Receptors, Vitronectin/antagonists & inhibitors
- Thrombospondins/antagonists & inhibitors
- Thrombospondins/metabolism
- Thrombospondins/pharmacology
- Thymidine/metabolism
- Transforming Growth Factor beta/metabolism
- Transforming Growth Factor beta/pharmacology
- Transforming Growth Factor beta1
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Affiliation(s)
- M Sajid
- Sealy Center for Molecular Cardiology, University of Texas Medical Branch, Galveston, Texas 77555, USA
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128
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Gallagher PJ, Jin Y, Killough G, Blue EK, Lindner V. Alterations in expression of myosin and myosin light chain kinases in response to vascular injury. Am J Physiol Cell Physiol 2000; 279:C1078-87. [PMID: 11003588 PMCID: PMC2824508 DOI: 10.1152/ajpcell.2000.279.4.c1078] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Histochemical analysis of balloon-injured rat carotid arteries revealed a coordinated expression of nonmuscle myosin heavy chain-A and -B (NM-A and NM-B) in response to injury. Expression of these nonmuscle myosin forms shifts from the media to the adventitia and intima. In contrast, expression of smooth muscle myosin heavy chain-1 (SM-1) within the media is not altered, whereas smooth muscle myosin heavy chain-2 (SM-2) expression declines. Western blotting shows a statistically significant increase in expression of NM-A that occurs within 6 h in response to carotid injury, suggesting this myosin form may be an appropriate experimental marker for proliferating, migrating cells in injured vessels. No overall change in the relative expression level of NM-B was detected, suggesting that compensatory declines in media expression are balanced by increases in the intima and adventitia. Expression of SM-1 did not change in response to injury, whereas the expression of SM-2 significantly declined between 24 h and 7 days. Expression of myosin light chain kinase is also negatively regulated, and the decline in its expression parallels downregulation of SM-2.
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Affiliation(s)
- P J Gallagher
- Department of Physiology, Indiana University School of Medicine, Indianapolis, Indiana 46202, USA.
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129
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Abstract
To achieve new insights into the coordinate regulation of gene expression during osteoblast differentiation we utilized an approach involving global analysis of gene expression to obtain the identities of messenger RNAs (mRNAs) expressed using an established in vitro model of bone development. MC3T3-E1 osteoblast-like cells were induced to differentiate by the addition of beta-glycerophosphate (beta-GP) and ascorbic acid. RNA samples derived from induced and uninduced control MC3T3-E1 cells were used to prepare complementary DNA (cDNA) for serial analysis of gene expression (SAGE). A preliminary SAGE database was produced and used to prepare a hybridization array to further facilitate the characterization of changes in the expression levels of 92 of the SAGE-mRNA assignments after induction of osteoblast differentiation, specifically after 6 days and 14 days of ascorbate treatment. SAGE-array hybridization analysis revealed coordinate induction of a number of mRNAs including Rab24, calponin, and calcyclin. Levels of MSY-1, SH3P2, fibronectin, alpha-collagen, procollagen, and LAMPI mRNAs, present at day 6 postinduction, were markedly reduced by day 14 postinduction. A number of unanticipated and potentially important developmental genes were identified including the transforming growth factor beta (TGF-beta) superfamily member Lefty-1. Lefty-1 transcript and translation product were found to be induced during the course of MC3T3-E1 cell differentiation. We present evidence, using transient transfection and antibody neutralization approaches, that Lefty-1 modulates the induction of alkaline phosphatase (ALP) after treatment of MC3T3-E1 cells with ascorbate and beta-GP. These data should provide useful new information for future analysis of transcriptional events in osteoblast differentiation and mineralization.
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Affiliation(s)
- A Seth
- MRC Group in Periodontal Physiology, and the Laboratory of Medicine and Pathobiology, University of Toronto, Sunnybrook, Canada
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130
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Lutgens E, Cleutjens KB, Heeneman S, Koteliansky VE, Burkly LC, Daemen MJ. Both early and delayed anti-CD40L antibody treatment induces a stable plaque phenotype. Proc Natl Acad Sci U S A 2000; 97:7464-9. [PMID: 10861013 PMCID: PMC16568 DOI: 10.1073/pnas.97.13.7464] [Citation(s) in RCA: 200] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
In the present study, we investigated the role of the CD40L-CD40 pathway in a model of progressive atherosclerosis. ApoE-/- mice were treated with an anti-CD40L antibody or a control antibody for 12 wk. Antibody treatment started early (age 5 wk) or was delayed until after the establishment of atherosclerosis (age 17 wk). In both the early and delayed treatment groups, anti-CD40L antibody did not decrease plaque area or inhibit lesion initiation or age-related increase in lesion area. The morphology of initial lesions was not affected, except for a decrease in T-lymphocyte content. Effects of anti-CD40L antibody treatment on the morphology of advanced lesions were pronounced. In both the early and delayed treatment groups, T-lymphocyte content was significantly decreased. Furthermore, a pronounced increase in collagen content, vascular smooth muscle cell/myofibroblast content, and fibrous cap thickness was observed. In the delayed treatment group, a decrease in lipid core and macrophage content occurred. Interestingly, advanced lesions of anti-CD40L antibody-treated mice exhibited an increased transforming growth factor beta1 immunoreactivity, especially in macrophages. In conclusion, both early and delayed treatment with an anti-CD40L antibody do not affect atherosclerotic lesion initiation but do result in the development of a lipid-poor collagen-rich stable plaque phenotype. Furthermore, delayed treatment with anti-CD40L antibody can transform the lesion profile from a lipid-rich to a lipid-poor collagen-rich phenotype. Postulated mechanisms of this effect on plaque phenotype are the down-regulation of proinflammatory pathways and up-regulation of collagen-promoting factors like transforming growth factor beta.
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Affiliation(s)
- E Lutgens
- Department of Pathology, Cardiovascular Research Institute Maastricht, University of Maastricht, P.O. Box 5800, 6202 AZ Maastricht, The Netherlands
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Agrotis A, Condron M, Bobik A. Alternative splicing within the TGF-beta type I receptor gene (ALK-5) generates two major functional isoforms in vascular smooth muscle cells. FEBS Lett 2000; 467:128-32. [PMID: 10664470 DOI: 10.1016/s0014-5793(00)01132-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
We have identified in rat vascular smooth muscle cells (SMCs) the simultaneous expression of two TGF-beta type I receptor (ALK-5) cDNAs, occurring as a consequence of alternate usage of AG splice acceptor motifs separated by 12 nucleotides located at an intron-exon junction. When translated the resultant full length proteins differ from each other only by the in-frame presence or absence of Gly-Pro-Phe-Ser residues adjacent to their transmembrane domain. Stable expression of these alternate ALK-5 isoforms in ALK-5-deficient cells demonstrated that both were competent in signaling TGF-beta-induced growth inhibition and gene transcription, but with an apparently distinct potency. Our data suggest that alternate splicing within the ALK-5 gene is an important mechanism whereby SMCs may regulate their response to TGF-beta.
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MESH Headings
- Activin Receptors, Type I
- Alternative Splicing/genetics
- Amino Acid Sequence
- Animals
- Aorta
- Base Sequence
- CHO Cells
- Cell Division/drug effects
- Cells, Cultured
- Cricetinae
- Exons/genetics
- Gene Expression/drug effects
- Humans
- Introns/genetics
- Molecular Sequence Data
- Muscle, Smooth, Vascular/cytology
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Protein Isoforms/chemistry
- Protein Isoforms/genetics
- Protein Isoforms/metabolism
- Protein Serine-Threonine Kinases/chemistry
- Protein Serine-Threonine Kinases/genetics
- Protein Serine-Threonine Kinases/metabolism
- Rats
- Rats, Inbred WKY
- Receptor, Transforming Growth Factor-beta Type I
- Receptors, Transforming Growth Factor beta/chemistry
- Receptors, Transforming Growth Factor beta/genetics
- Receptors, Transforming Growth Factor beta/metabolism
- Signal Transduction/drug effects
- Transfection
- Transforming Growth Factor beta/pharmacology
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Affiliation(s)
- A Agrotis
- Cell Biology Laboratory, Baker Medical Research Institute, Alfred Hospital, Prahran, Vic., Australia.
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