1
|
Abstract
Primary and secondary forms of focal segmental glomerulosclerosis (FSGS) are characterized by depletion of podocytes and constitute a central manifestation of chronic progressive glomerular diseases. Here we report that podocytes undergo apoptosis at early stages in the course of progressive glomerulosclerosis in TGF-beta1 transgenic mice. Apoptosis is associated with progressive depletion of podocytes and precedes mesangial expansion. Smad7 protein expression is strongly induced specifically in damaged podocytes of transgenic mice and in cultured murine podocytes treated with TGF-beta. TGF-beta1 and Smad7 each induce apoptosis in podocytes, and their coexpression has an additive effect. Activation of p38 MAP kinase and caspase-3 is required for TGF-beta-mediated apoptosis, but not for apoptosis induced by Smad7. Unlike TGF-beta, Smad7 inhibits nuclear translocation and transcriptional activity of the cell survival factor NF-kappaB. Our results suggest a novel functional role for Smad7 as amplifier of TGF-beta-induced apoptosis in podocytes and a new pathomechanism for podocyte depletion in progressive glomerulosclerosis.
Collapse
Affiliation(s)
- M Schiffer
- Division of Nephrology, Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | | | | | | | | | | | | |
Collapse
|
2
|
Schiffer M, Bitzer M, Roberts IS, Kopp JB, ten Dijke P, Mundel P, Böttinger EP. Apoptosis in podocytes induced by TGF-beta and Smad7. J Clin Invest 2001; 108:807-16. [PMID: 11560950 PMCID: PMC200928 DOI: 10.1172/jci12367] [Citation(s) in RCA: 223] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Primary and secondary forms of focal segmental glomerulosclerosis (FSGS) are characterized by depletion of podocytes and constitute a central manifestation of chronic progressive glomerular diseases. Here we report that podocytes undergo apoptosis at early stages in the course of progressive glomerulosclerosis in TGF-beta1 transgenic mice. Apoptosis is associated with progressive depletion of podocytes and precedes mesangial expansion. Smad7 protein expression is strongly induced specifically in damaged podocytes of transgenic mice and in cultured murine podocytes treated with TGF-beta. TGF-beta1 and Smad7 each induce apoptosis in podocytes, and their coexpression has an additive effect. Activation of p38 MAP kinase and caspase-3 is required for TGF-beta-mediated apoptosis, but not for apoptosis induced by Smad7. Unlike TGF-beta, Smad7 inhibits nuclear translocation and transcriptional activity of the cell survival factor NF-kappaB. Our results suggest a novel functional role for Smad7 as amplifier of TGF-beta-induced apoptosis in podocytes and a new pathomechanism for podocyte depletion in progressive glomerulosclerosis.
Collapse
Affiliation(s)
- M Schiffer
- Division of Nephrology, Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | | | | | | | | | | | | |
Collapse
|
3
|
Roberts AB, Piek E, Böttinger EP, Ashcroft G, Mitchell JB, Flanders KC. Is Smad3 a major player in signal transduction pathways leading to fibrogenesis? Chest 2001. [PMID: 11451911 DOI: 10.1016/s0012-3692(15)38703-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
Abstract
Transforming growth factor (TGF)-beta plays a central role in fibrosis, contributing both to the influx and activation of inflammatory cells, as well as to activation of fibroblasts to elaborate extracellular matrix. In the past few years, new insight has been gained into signal transduction pathways downstream of the TGF-beta receptor serine-threonine kinases with the identification of a family of evolutionarily conserved Smad proteins. Two receptor-activated Smad proteins, Smad2 and Smad3, are phosphorylated by the activated TGF-beta type I receptor kinase, after which they partner with the common mediator, Smad4, and are translocated to the nucleus to where they participate in transcriptional complexes to control expression of target genes. We have shown in wound healing studies of mice null for Smad3, that loss of this key signaling intermediate interferes with the chemotaxis of inflammatory cells to TGF-beta as well as with their ability to autoinduce TGF-beta. Moreover, studies with mouse embryo fibroblasts null for Smad3 show that TGF-beta-dependent induction of c-Jun and c-Fos, important in induction of collagen as well as in autoinduction of TGF-beta, is mediated by Smad3. Based on these observations, we hypothesize that loss of Smad3 will confer resistance to fibrosis and result in reduced inflammatory cell infiltrates, reduced autoinduction of TGF-beta, important to sustain the process, and reduced elaboration of collagen. Preliminary observations in a model of radiation-induced fibrosis confirm this hypothesis and suggest that inhibitors of Smad3 might have clinical application both to improve wound healing and to reduce fibrosis.
Collapse
Affiliation(s)
- A B Roberts
- Laboratory of Cell Regulation and Carcinogenesis, National Cancer Institute, Bethesda, MD 20892-5055, USA.
| | | | | | | | | | | |
Collapse
|
4
|
Abstract
Transforming growth factor (TGF)-beta plays a central role in fibrosis, contributing both to the influx and activation of inflammatory cells, as well as to activation of fibroblasts to elaborate extracellular matrix. In the past few years, new insight has been gained into signal transduction pathways downstream of the TGF-beta receptor serine-threonine kinases with the identification of a family of evolutionarily conserved Smad proteins. Two receptor-activated Smad proteins, Smad2 and Smad3, are phosphorylated by the activated TGF-beta type I receptor kinase, after which they partner with the common mediator, Smad4, and are translocated to the nucleus to where they participate in transcriptional complexes to control expression of target genes. We have shown in wound healing studies of mice null for Smad3, that loss of this key signaling intermediate interferes with the chemotaxis of inflammatory cells to TGF-beta as well as with their ability to autoinduce TGF-beta. Moreover, studies with mouse embryo fibroblasts null for Smad3 show that TGF-beta-dependent induction of c-Jun and c-Fos, important in induction of collagen as well as in autoinduction of TGF-beta, is mediated by Smad3. Based on these observations, we hypothesize that loss of Smad3 will confer resistance to fibrosis and result in reduced inflammatory cell infiltrates, reduced autoinduction of TGF-beta, important to sustain the process, and reduced elaboration of collagen. Preliminary observations in a model of radiation-induced fibrosis confirm this hypothesis and suggest that inhibitors of Smad3 might have clinical application both to improve wound healing and to reduce fibrosis.
Collapse
Affiliation(s)
- A B Roberts
- Laboratory of Cell Regulation and Carcinogenesis, National Cancer Institute, Bethesda, MD 20892-5055, USA.
| | | | | | | | | | | |
Collapse
|
5
|
Razani B, Zhang XL, Bitzer M, von Gersdorff G, Böttinger EP, Lisanti MP. Caveolin-1 regulates transforming growth factor (TGF)-beta/SMAD signaling through an interaction with the TGF-beta type I receptor. J Biol Chem 2001; 276:6727-38. [PMID: 11102446 DOI: 10.1074/jbc.m008340200] [Citation(s) in RCA: 498] [Impact Index Per Article: 21.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Transforming growth factor-beta (TGF-beta) signaling proceeds from the cell membrane to the nucleus through the cooperation of the type I and II serine/threonine kinase receptors and their downstream SMAD effectors. Although various regulatory proteins affecting TGF-beta-mediated events have been described, relatively little is known about receptor interactions at the level of the plasma membrane. Caveolae are cholesterol-rich membrane microdomains that, along with their marker protein caveolin-1 (Cav-1), have been implicated in the compartmentalization and regulation of certain signaling events. Here, we demonstrate that specific components of the TGF-beta cascade are associated with caveolin-1 in caveolae and that Cav-1 interacts with the Type I TGF-beta receptor. Additionally, Cav-1 is able to suppress TGF-beta-mediated phosphorylation of Smad-2 and subsequent downstream events. We localize the Type I TGF-beta receptor interaction to the scaffolding domain of Cav-1 and show that it occurs in a physiologically relevant time frame, acting to rapidly dampen signaling initiated by the TGF-beta receptor complex.
Collapse
Affiliation(s)
- B Razani
- Department of Molecular Pharmacology and The Albert Einstein Cancer Center and the Departments of Medicine and Molecular Genetics, Albert Einstein College of Medicine, Bronx, New York 10461
| | | | | | | | | | | |
Collapse
|
6
|
Abstract
Ligands of the TGF-beta superfamily are unique in that they signal through transmembrane receptor serine-threonine kinases, rather than tyrosine kinases. The receptor complex couples to a signal transduction pathway involving a novel family of proteins, the Smads. On phosphorylation, Smads translocate to the nucleus where they modulate transcriptional responses. However, TGF-betas can also activate the mitogen-activated protein kinase (MAPK)4 pathway, and the different biological responses to TGF-beta depend to varying degrees on activation of either or both of these two pathways. The Smad pathway is a nexus for cross-talk with other signal transduction pathways and for modulation by many different interacting proteins. Despite compelling evidence that TGF-beta has tumor suppressor activity in the mammary gland, neither TGF-beta receptors nor Smads are genetically inactivated in human breast cancer, though receptor expression is reduced. Possible reasons are discussed in relation to the dual role of TGF-beta as tumor suppressor and oncogene.
Collapse
Affiliation(s)
- L M Wakefield
- Laboratory of Cell Regulation and Carcinogenesis, National Cancer Institute, Bethesda, Maryland, USA.
| | | | | |
Collapse
|
7
|
Abstract
An extensive number of animal and clinical studies indicate that transforming growth factor-beta (TGF-beta s) play an important role in inflammatory and fibrotic diseases, including renal fibrosis. Recent mouse models harboring genetically engineered alterations in TGF-beta pathways reveal complicated mechanisms of regulation of TGF-beta activity in vivo. The purpose of this review is to present recent advances relevant to our understanding of the TGF-beta-signaling system in renal physiology and pathophysiology.
Collapse
Affiliation(s)
- M Bitzer
- Medizinische Klinik IV mit Poliklinik, Friedrich-Alexander Universität Erlangen-Nürnberg, Germany.
| | | | | |
Collapse
|
8
|
Böttinger EP, Miao J, Schiffer M, Bitzer M, Roberts IS. Transforming growth factor beta signal transduction in the kidney. Kidney Blood Press Res 2000; 21:259-61. [PMID: 9762849 DOI: 10.1159/000025870] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Affiliation(s)
- E P Böttinger
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY 10461, USA.
| | | | | | | | | |
Collapse
|
9
|
Abstract
It is now generally accepted that transforming growth factor-beta (TGF-beta) has an important role in the pathogenesis of both acute and chronic forms of renal disease. Although TGF-beta's potent fibrogenic activity is considered a major factor in chronic progression of renal disease, this cytokine participates in the control of several fundamental cellular responses in the kidney including inflammation, programmed cell death, cell growth, cell differentiation, and cellular hypertrophy. Recent identification of Smad proteins as intracellular mediators of TGF-beta signaling has provided important insights into mechanisms that may determine the specificity of TGF-beta action in different renal and inflammatory cells. Thus, Smads are characterized by an astonishingly complex array of molecular and functional interactions with other signaling pathways. These emerging patterns of signaling cross talk involving Smad proteins suggest a dynamic profile of positive or negative transmodulation of TGF-beta signaling, depending on the cellular context. Understanding the interplay between these signaling cascades is an important field of investigation that will ultimately reveal new targets for precise and selective modulation of TGF-beta's diverse actions in renal diseases.
Collapse
Affiliation(s)
- M Schiffer
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | | | | | | | | |
Collapse
|
10
|
Grainger DJ, Mosedale DE, Metcalfe JC, Böttinger EP. Dietary fat and reduced levels of TGFbeta1 act synergistically to promote activation of the vascular endothelium and formation of lipid lesions. J Cell Sci 2000; 113 ( Pt 13):2355-61. [PMID: 10852815 DOI: 10.1242/jcs.113.13.2355] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Transforming growth factor-(beta) (TGF(beta)) has a wide range of activities on vascular cells and inflammatory cells, suggesting it may have different functions during various stages of atherogenesis. We report that mice heterozygous for the deletion of the tgfb1 gene (tgfb1(+/-) mice) have reduced levels of TGF(beta)1 in the artery wall until at least 8 weeks of age. On a normal mouse chow diet, the vascular endothelium of tgfb1(+/-) mice is indistinguishable from wild-type littermates, assessed by morphology and intercellular cell adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) expression. In contrast, levels of the smooth muscle isoforms of actin and myosin in medial smooth muscle cells of tgfb1(+/-) mice are significantly reduced. Following feeding a cholesterol-enriched diet for 12 weeks, high levels of ICAM-1 and VCAM-1 were detected in the vascular endothelial cells of tgfb1(+/-) mice, but not wild-type mice. Furthermore, marked deposition of lipid into the artery wall was only observed in the tgfb1(+/-) mice on the cholesterol-enriched diet. These vascular lipid lesions were accompanied by local invasion of macrophages. We conclude that deletion of a single allele of the tgfb1 gene results in a reduced level of TGFbeta1 antigen in the aorta together with reduced smooth muscle cell differentiation, whereas the addition of a high fat dietary challenge is required to activate the vascular endothelium and to promote the formation of fatty streaks resembling early atherosclerosis in humans.
Collapse
MESH Headings
- Animals
- Aorta/metabolism
- Aorta/pathology
- Aorta/physiopathology
- Arteriosclerosis/etiology
- Arteriosclerosis/pathology
- Arteriosclerosis/physiopathology
- Dietary Fats/adverse effects
- Endothelium, Vascular/metabolism
- Endothelium, Vascular/pathology
- Endothelium, Vascular/physiopathology
- Inflammation/pathology
- Inflammation/physiopathology
- Lipid Metabolism
- Lipoproteins/metabolism
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/pathology
- Muscle, Smooth, Vascular/physiopathology
- Transforming Growth Factor beta/deficiency
Collapse
Affiliation(s)
- D J Grainger
- Department of Medicine, Box 157, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 2QQ, UK.
| | | | | | | |
Collapse
|
11
|
von Gersdorff G, Susztak K, Rezvani F, Bitzer M, Liang D, Böttinger EP. Smad3 and Smad4 mediate transcriptional activation of the human Smad7 promoter by transforming growth factor beta. J Biol Chem 2000; 275:11320-6. [PMID: 10753944 DOI: 10.1074/jbc.275.15.11320] [Citation(s) in RCA: 140] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Smad7 is an inducible intracellular inhibitor of transforming growth factor-beta (TGF-beta) signaling that is regulated by diverse stimuli including members of the TGF-beta superfamily. To define the molecular mechanisms of negative control of TGF-beta signaling, we have isolated the human SMAD7 gene and characterized its promoter region. A -303 to +672 SMAD7 region contained a palindromic GTCTAGAC Smad binding element (SBE) between nucleotides -179 and -172 that was necessary for the induction of a Smad7 promoter luciferase reporter gene by TGF-beta. Electrophoretic mobility shift assays using oligonucleotide probes demonstrated that TGF-beta rapidly induced the binding of an endogenous SBE-binding complex (SBC) containing Smad2, Smad3, and Smad4. Transfection assays in mouse embryonic fibroblasts (MEFs), with targeted deletions of either Smad2 or Smad3, and the Smad4-deficient cell line MD-MBA-468 revealed that both Smad3 and Smad4, but not Smad2, were absolutely required for induction of the Smad7 promoter reporter gene by TGF-beta. Furthermore, the TGF-beta-inducible SBE-binding complex was diminished in Smad2-deficient MEFs when compared with wild type MEFs and not detectable in Smad3-deficient MEFs and MD-MBA-468 cells. Taken together, our data demonstrate that TGF-beta induces transcription of the human SMAD7 gene through activation of Smad3 and Smad4 transcription factor binding to its proximal promoter.
Collapse
Affiliation(s)
- G von Gersdorff
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461, USA
| | | | | | | | | | | |
Collapse
|
12
|
Bitzer M, von Gersdorff G, Liang D, Dominguez-Rosales A, Beg AA, Rojkind M, Böttinger EP. A mechanism of suppression of TGF-beta/SMAD signaling by NF-kappa B/RelA. Genes Dev 2000; 14:187-97. [PMID: 10652273 PMCID: PMC316349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
A number of pathogenic and proinflammatory stimuli, and the transforming growth factor-beta (TGF-beta) exert opposing activities in cellular and immune responses. Here we show that the RelA subunit of nuclear factor kappaB (NF-kappaB/RelA) is necessary for the inhibition of TGF-beta-induced phosphorylation, nuclear translocation, and DNA binding of SMAD signaling complexes by tumor necrosis factor-alpha (TNF-alpha). The antagonism is mediated through up-regulation of Smad7 synthesis and induction of stable associations between ligand-activated TGF-beta receptors and inhibitory Smad7. Down-regulation of endogenous Smad7 by expression of antisense mRNA releases TGF-beta/SMAD-induced transcriptional responses from suppression by cytokine-activated NF-kappaB/RelA. Following stimulation with bacterial lipopolysaccharide (LPS), or the proinflammatory cytokines TNF-alpha and interleukin-1beta (IL-1beta, NF-kappaB/RelA induces Smad7 synthesis through activation of Smad7 gene transcription. These results suggest a mechanism of suppression of TGF-beta/SMAD signaling by opposing stimuli mediated through the activation of inhibitory Smad7 by NF-kappaB/RelA.
Collapse
Affiliation(s)
- M Bitzer
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York 10461 USA
| | | | | | | | | | | | | |
Collapse
|
13
|
Tang B, de Castro K, Barnes HE, Parks WT, Stewart L, Böttinger EP, Danielpour D, Wakefield LM. Loss of responsiveness to transforming growth factor beta induces malignant transformation of nontumorigenic rat prostate epithelial cells. Cancer Res 1999; 59:4834-42. [PMID: 10519393] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Abstract
Transforming growth factor (TGF)-betas are multifunctional growth factors, the properties of which include the potent inhibition of epithelial cell growth. Expression patterns of TGF-betas and TGF-beta receptors in the normal prostate indicate that these growth regulators play key roles in prostatic development and proliferative homeostasis. Importantly, TGF-beta receptor levels are frequently diminished in malignant human prostate tissue. To test the hypothesis that loss of TGF-beta responsiveness is causally involved in the tumorigenic process, we have used retroviral transduction to introduce a dominant-negative mutant type II TGF-beta receptor (DNR) into the premalignant rat prostatic epithelial cell line, NRP-152. High-level expression of the DNR abolished the ability of TGF-beta to inhibit cell growth, to promote cell differentiation, and to induce apoptosis, and it partially blocked the induction of extracellular matrix gene expression. When injected into nude mice, NRP-152-DNR cells formed carcinomas at 13 of 34 sites, compared with 0 of 30 sites for parental and control cells (P = 0.0001). We conclude that the type II TGF-beta receptor is an important tumor suppressor in the prostate, and furthermore, that loss of TGF-beta responsiveness can contribute early in the tumorigenic process by causing the malignant transformation of preneoplastic cells.
Collapse
Affiliation(s)
- B Tang
- Laboratory of Cell Regulation and Carcinogenesis, National Cancer Institute, Bethesda, Maryland 20892-5055, USA
| | | | | | | | | | | | | | | |
Collapse
|
14
|
Mozes MM, Böttinger EP, Jacot TA, Kopp JB. Renal expression of fibrotic matrix proteins and of transforming growth factor-beta (TGF-beta) isoforms in TGF-beta transgenic mice. J Am Soc Nephrol 1999; 10:271-80. [PMID: 10215326 DOI: 10.1681/asn.v102271] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022] Open
Abstract
Renal pathology in mice that are transgenic for the murine albumin enhancer/promoter linked to a full-length porcine transforming growth factor-beta1 (TGF-beta1) gene has been described previously. In these mice, transgene expression is limited to the liver and the plasma level of TGF-beta is increased. The earliest renal pathologic change is glomerulosclerosis, at 3 wk of age, and this is followed by tubulointerstitial fibrosis. In this study, it was hypothesized that circulating TGF-beta1 increases renal extracellular matrix accumulation and activates local TGF-beta gene expression. Immunostaining at 5 wk revealed increased amounts of collagen I and III within the mesangium, glomerular capillary loops, and interstitium, while the amount of collagen IV was normal. Similarly, Northern analysis showed increased expression of mRNA encoding collagen I and III, as well as biglycan and decorin, while the expression of collagen IV was unchanged. These changes began as early as 1 wk of age, a time before the appearance of glomerulosclerosis. To evaluate matrix degradation, collagenase IV activity was evaluated by gelatin zymography and an increase in matrix metalloproteinase-2 was found. Finally, the production of tissue inhibitors of metalloproteinase was evaluated. Tissue inhibitor of metalloproteinase-1 (TIMP-1) mRNA was increased 18-fold, while TIMP-2 and TIMP-3 were unchanged. In 2-wk-old transgenic kidney, local expression of TGF-beta1, beta2, and beta3 protein was similar to wild-type mice. In 5-wk-old transgenic mice, TGF-beta1 and beta2 protein was present in increased amounts within glomeruli, and renal TGF-beta1 mRNA was increased threefold. It is concluded that elevated levels of circulating TGF-beta1 may act on the kidney to increase matrix protein production and decrease matrix remodeling. Only after glomerulosclerosis is established does local glomerular overproduction of TGF-beta become manifest.
Collapse
Affiliation(s)
- M M Mozes
- Institute of Pathophysiology, Semmelweis University Medical School, Budapest, Hungary
| | | | | | | |
Collapse
|
15
|
Tang B, Böttinger EP, Jakowlew SB, Bagnall KM, Mariano J, Anver MR, Letterio JJ, Wakefield LM. Transforming growth factor-beta1 is a new form of tumor suppressor with true haploid insufficiency. Nat Med 1998; 4:802-7. [PMID: 9662371 DOI: 10.1038/nm0798-802] [Citation(s) in RCA: 245] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Components of the transforming growth factor-beta (TGF-beta) signal pathway function as classic tumor suppressors, but the role of the TGF-betas themselves is less clear. Here we show that mice heterozygous for deletion of the TGF-beta1 gene express only 10-30% of wild-type TGF-beta1 protein levels. Although grossly normal, these mice have a subtly altered proliferative phenotype, with increased cell turnover in the liver and lung. Treatment of these mice with chemical carcinogens resulted in enhanced tumorigenesis when compared with wild-type littermates. However, tumors in the heterozygous mice did not lose the remaining wild-type TGF-beta1 allele, indicating that the TGF-beta1 ligand is a new form of tumor suppressor that shows true haploid insufficiency in its ability to protect against tumorigenesis.
Collapse
Affiliation(s)
- B Tang
- Laboratory of Cell Regulation and Carcinogenesis (formerly Laboratory of Chemoprevention), National Cancer Institute, Bethesda, Maryland 20892-5055, USA
| | | | | | | | | | | | | | | |
Collapse
|
16
|
Abstract
Use of homologous recombination and transgenic technologies have provided mouse models to study the physiological roles of the three mammalian TGF-beta isoforms, and their regulation in the context of the intact animal. Mice harboring null mutations for TGF-beta isoforms demonstrate that each exerts discrete nonoverlapping functions during development. TGF-beta1 null mice reveal a crucial role for this cytokine in modulation of the immune system, with evidence for altered development, activation and function of various immune cell populations. New approaches to tissue- and cell-restricted disruption of TGF-beta signaling pathways in transgenic mice carrying dominant-negative mutant TGF-beta receptors will be discussed.
Collapse
Affiliation(s)
- J J Letterio
- Laboratory of Chemoprevention, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-5055, USA.
| | | |
Collapse
|
17
|
Abstract
Aberrant expression of TGF-beta and/or receptor/signaling function is present in a wide variety of disease processes. Overexpression of TGF-beta isoforms in transgenic mice using tissue-specific promoters has provided model systems to study the effects of increased activity of TGF-beta in the intact organism. We will review the pertinent features of some of these models, and discuss new insights provided by these studies into regulation and role of TGF-beta in health and disease.
Collapse
Affiliation(s)
- E P Böttinger
- Division of Nephrology, Albert Einstein College of Medicine, Bronx, NY 10461-1602, USA.
| | | |
Collapse
|
18
|
Böttinger EP, Jakubczak JL, Haines DC, Bagnall K, Wakefield LM. Transgenic mice overexpressing a dominant-negative mutant type II transforming growth factor beta receptor show enhanced tumorigenesis in the mammary gland and lung in response to the carcinogen 7,12-dimethylbenz-[a]-anthracene. Cancer Res 1997; 57:5564-70. [PMID: 9407968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
To test the hypothesis that the transforming growth factor-beta (TGF-beta) system has tumor suppressor activity in the mammary gland, we have generated transgenic mice overexpressing a dominant-negative mutant form of the type II TGF-beta receptor, under the control of the mouse mammary tumor virus-long terminal repeat. High-level expression of the transgene was observed in the mammary and salivary glands, with lower expression in the lung, spleen, and testis. Older nulliparous transgenic mice (9-17 months) showed a marked increase in the incidence and degree of lobulo-alveolar side-branching in the mammary glands when compared to wild-type littermates (24.8% of glands examined histologically versus 14.4%; P = 0.004), suggesting a role for endogenous TGF-betas in regulating development or maintenance of mammary alveoli. Spontaneous tumorigenesis was unchanged in the transgenic mice. However, following initiation with the carcinogen 7,12-dimethylbenz[a]anthracene, the transgenic group showed a significant increase in the incidence and multiplicity of mammary tumors when compared with wild-type littermates (40% incidence in transgenic mice versus 22% for wild-type, with 4 of 25 transgenics developing multiple mammary tumors versus 0 of 27 wild-type; P = 0.03). An early increase in the incidence of lung tumors was also observed in transgenic mice, but no difference between genotype groups was seen in the incidence of tumors in tissues in which the transgene is not expressed. The data show that the endogenous TGF-beta system has tumor suppressor activity in the mammary gland and lung.
Collapse
MESH Headings
- 9,10-Dimethyl-1,2-benzanthracene/toxicity
- Animals
- Carcinogens/toxicity
- Cocarcinogenesis
- Female
- Gene Expression
- Humans
- Lung/drug effects
- Lung/physiology
- Lung/ultrastructure
- Lung Neoplasms/chemically induced
- Lung Neoplasms/ultrastructure
- Male
- Mammary Glands, Animal/drug effects
- Mammary Glands, Animal/physiology
- Mammary Glands, Animal/ultrastructure
- Mammary Neoplasms, Experimental/chemically induced
- Mammary Neoplasms, Experimental/ultrastructure
- Mice
- Mice, Transgenic
- Mutation
- Protein Serine-Threonine Kinases
- Receptor, Transforming Growth Factor-beta Type II
- Receptors, Transforming Growth Factor beta/biosynthesis
- Receptors, Transforming Growth Factor beta/genetics
- Receptors, Transforming Growth Factor beta/physiology
- Transfection
- Transforming Growth Factor beta/metabolism
- Transgenes
Collapse
Affiliation(s)
- E P Böttinger
- Laboratories of Chemoprevention, National Cancer Institute, Bethesda, Maryland 20892, USA
| | | | | | | | | |
Collapse
|
19
|
Böttinger EP, Jakubczak JL, Roberts IS, Mumy M, Hemmati P, Bagnall K, Merlino G, Wakefield LM. Expression of a dominant-negative mutant TGF-beta type II receptor in transgenic mice reveals essential roles for TGF-beta in regulation of growth and differentiation in the exocrine pancreas. EMBO J 1997; 16:2621-33. [PMID: 9184209 PMCID: PMC1169873 DOI: 10.1093/emboj/16.10.2621] [Citation(s) in RCA: 200] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Using a dominant-negative mutant receptor (DNR) approach in transgenic mice, we have functionally inactivated transforming growth factor-beta (TGF-beta) signaling in select epithelial cells. The dominant-negative mutant type II TGF-beta receptor blocked signaling by all three TGF-beta isoforms in primary hepatocyte and pancreatic acinar cell cultures generated from transgenic mice, as demonstrated by the loss of growth inhibitory and gene induction responses. However, it had no effect on signaling by activin, the closest TGF-beta family member. DNR transgenic mice showed increased proliferation of pancreatic acinar cells and severely perturbed acinar differentiation. These results indicate that TGF-beta negatively controls growth of acinar cells and is essential for the maintenance of a differentiated acinar phenotype in the exocrine pancreas in vivo. In contrast, such abnormalities were not observed in the liver. Additional abnormalities in the pancreas included fibrosis, neoangiogenesis and mild macrophage infiltration, and these were associated with a marked up-regulation of TGF-beta expression in transgenic acinar cells. This transgenic model of targeted functional inactivation of TGF-beta signaling provides insights into mechanisms whereby loss of TGF-beta responsiveness might promote the carcinogenic process, both through direct effects on cell proliferation, and indirectly through up-regulation of TGF-betas with associated paracrine effects on stromal compartments.
Collapse
Affiliation(s)
- E P Böttinger
- Laboratory of Chemoprevention, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | | | | | | | | | | | | | | |
Collapse
|
20
|
Abstract
This paper reviews the basic biology and biochemistry of the TGF-beta isoforms including their unique serine-threonine receptors and signaling intermediates. Dysregulation of TGF-beta expression and/or receptor/signaling function have been implicated in a wide variety of pathologies. We will discuss mechanisms underlying some of these disease processes as gained from study of transgenic mice in which expression of TGF-beta 1 has either been lost by targeted deletion of its gene, is overexpressed in a tissue-specific manner, or blocked by its latency associated peptide.
Collapse
Affiliation(s)
- E P Böttinger
- Laboratory of Chemoprevention, National Cancer Institute, Bethesda, Maryland, USA
| | | | | |
Collapse
|
21
|
Böttinger EP, Factor VM, Tsang ML, Weatherbee JA, Kopp JB, Qian SW, Wakefield LM, Roberts AB, Thorgeirsson SS, Sporn MB. The recombinant proregion of transforming growth factor beta1 (latency-associated peptide) inhibits active transforming growth factor beta1 in transgenic mice. Proc Natl Acad Sci U S A 1996; 93:5877-82. [PMID: 8650186 PMCID: PMC39155 DOI: 10.1073/pnas.93.12.5877] [Citation(s) in RCA: 121] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
All three isoforms of transforming growth factors beta (TGF-betal, TGF-beta2, and TGF-beta3) are secreted as latent complexes and activated extracellularly, leading to the release of the mature cytokines from their noncovalently associated proregions, also known as latency-associated peptides (LAPs). The LAP region of TGF-beta1 was expressed in a baculovirus expression system and purified to homogeneity. In vitro assays of growth inhibition and gene induction mediated by TGF-beta3 demonstrate that recombinant TGF-beta1 LAP is a potent inhibitor of the activities of TGF-betal, -beta2, and -beta3. Effective dosages of LAP for 50% neutralization of TGF-beta activities range from 4.7- to 80-fold molar excess depending on the TGF-beta isoform and activity examined. Using 125I-labeled LAP, we show that the intraperitoneal application route is effective for systemic administration of LAP. Comparison of concentrations of LAP in tissues shows a homogenous pattern in most organs with the exception of heart and muscle, in which levels of LAP are 4- to 8-fold lower. In transgenic mice with elevated hepatic levels of bioactive TGF-betal, treatment with recombinant LAP completely reverses suppression of the early proliferative response induced by TGF-beta1 in remnant livers after partial hepatectomy. The results suggest that recombinant LAP is a potent inhibitor of bioactive TGF-beta both in vitro and in vivo, after intraperitoneal administration. Recombinant LAP should be a useful tool for novel approaches to study and therapeutically modulate pathophysiological processes mediated by TGF-beta3.
Collapse
Affiliation(s)
- E P Böttinger
- Laboratory of Chemoprevention, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892-5055, USA
| | | | | | | | | | | | | | | | | | | |
Collapse
|
22
|
Kopp JB, Factor VM, Mozes M, Nagy P, Sanderson N, Böttinger EP, Klotman PE, Thorgeirsson SS. Transgenic mice with increased plasma levels of TGF-beta 1 develop progressive renal disease. J Transl Med 1996; 74:991-1003. [PMID: 8667617] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Several lines of evidence suggest that local production of transforming growth factor-beta (TGF-beta) contributes to renal disease, particularly to the accumulation of the extracellular matrix protein that characterizes glomerulosclerosis and interstitial fibrosis. We have examined whether elevated levels of circulating TGF-beta adversely affect the kidney. We have studied mice that are transgenic for an active form of TGF-beta 1 under the control of murine albumin promoter and enhancer DNA sequences. These mice express the transgene exclusively in the liver and have elevated plasma concentrations of TGF-beta 1. Renal disease was seen in two of three lines of Alb/TGF-beta 1 transgenic mice; these two lines had the highest levels of hepatic transgene expression and the highest plasma TGF-beta 1 levels. Histologic abnormalities, which included mesangial expansion and thickened capillary loops, were noted in the glomeruli by 3 weeks of age. Interstitial fibrosis and tubular atrophy appeared subsequently. Mice from Line 25, the line with highest levels of TGF-beta 1, developed proteinuria by 5 weeks of age. These mice subsequently manifested nephrotic syndrome with ascites and progressive azotemia; uremic death occurred in more than 25% of the mice by 15 weeks of age. The glomeruli contained immune deposits in subendothelial and mesangial locations, but complement deposition was infrequent. Ultrastructural examination revealed an increase in extracellular matrix material, including collagen fibrils, in subendothelial and mesangial locations. Increased levels of circulating TGF-beta 1 induced progressive renal disease that was characterized by mesangial expansion, accumulation of glomerular immune deposits and matrix proteins, and interstitial fibrosis in this transgenic mouse model. These data suggest that chronically elevated circulating levels of TGF-beta 1 induce progressive glomerulosclerosis.
Collapse
Affiliation(s)
- J B Kopp
- Kidney Disease Section, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, Maryland 20892, USA
| | | | | | | | | | | | | | | |
Collapse
|
23
|
Niles JL, Böttinger EP, Saurina GR, Kelly KJ, Pan G, Collins AB, McCluskey RT. The syndrome of lung hemorrhage and nephritis is usually an ANCA-associated condition. Arch Intern Med 1996; 156:440-5. [PMID: 8607730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
BACKGROUND In the absence of evidence of arteritis or Wegener's granulomatosis, the syndrome of lung hemorrhage and nephritis has been commonly associated with anti-glomerular basement membrane (GBM) antibodies. However, it has been increasingly recognized that many cases are associated with antineutrophil cytoplasmic antibodies (ANCAs). OBJECTIVE To review available clinical and pathologic findings to determine the diseases accounting for lung hemorrhage and nephritis. METHODS We studied the records of 750 patients from whom serum samples were sent to our laboratory for anti-GBM antibody assays between 1981 and 1993 and found 88 patients with evidence of lung hemorrhage and nephritis. Serum samples were retested, using current methods, for anti-GBM antibodies (against noncollagenous 1 domain of the alpha 3 chain of type IV collagen) and for antibodies to proteinase 3 and myeloperoxidase--the two types of ANCA of diagnostic value. RESULTS Of 88 patients with evidence of lung hemorrhage and nephritis, 48 had ANCAs, six had anti-GBM antibodies, and seven had both. In 48 patients with ANCAs, the pathologic findings that accounted for the pulmonary renal syndrome were pauci-immune necrotizing and crescentic glomerulonephritis and pulmonary capillaritis. Only eight had convincing evidence (during life) of Wegener's granulomatosis and only one other had documented arteritis. In 27 patients without ANCAs or anti-GBM antibodies, a variety of unrelated renal and pulmonary diseases were found. CONCLUSIONS The largest group of patients who present with the syndrome of lung hemorrhage and nephritis have ANCAs and not anti-GMB antibodies. Appropriate tests for antibodies to proteinase 3, antibodies to myeloperoxidase, and anti-GBM antibodies provide reliable guides for making a diagnosis in patients with this pulmonary renal syndrome.
Collapse
Affiliation(s)
- J L Niles
- Department of Medicine, Massachusetts General Hospital, Boston, USA
| | | | | | | | | | | | | |
Collapse
|
24
|
Amatayakul-Chantler S, Qian SW, Gakenheimer K, Böttinger EP, Roberts AB, Sporn MB. [Ser77]transforming growth factor-beta 1. Selective biological activity and receptor binding in mink lung epithelial cells. J Biol Chem 1994; 269:27687-91. [PMID: 7961688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Transforming growth factor-beta 1 (TGF-beta 1) is a homodimeric protein stabilized by a single disulfide bridge between Cys77 on the respective monomers and two paired complementary hydrophobic interfaces between the two subunits. A TGF-beta 1 mutant with Cys77 replaced by serine has been expressed in stably transfected Chinese hamster ovary cells and purified to homogeneity. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis confirms that the sole interchain disulfide bond in TGF-beta 1 has been eliminated. It is 20% as potent as native TGF-beta 1 in the induction of plasminogen activator inhibitor-1 promoter expression in mink lung epithelial cells (Mv1Lu), although it is less than 1% as potent as native TGF-beta 1 in inhibition of growth in the same cell line. The mutant acts as a full agonist in both bioassays. [Ser77]TGF-beta 1 binds to soluble type II receptors and competes with native TGF-beta 1 in sandwich-enzyme-linked immunosorbent assays; however, in Mv1Lu cells, the mutant shows preferential cross-linking to type I rather than type II receptors. [Ser77]TGF-beta 1 is a useful tool for understanding the different ligand-receptor complexes and numerous biological activities of this multifunctional cytokine.
Collapse
Affiliation(s)
- S Amatayakul-Chantler
- Laboratory of Chemoprevention, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892
| | | | | | | | | | | |
Collapse
|
25
|
Abstract
To define the minimal promoter responsible for expression of CD18 in myeloid and lymphoid cells, we generated 5' and 3' deletion constructs of a segment extending 785 bp upstream and 19 bp downstream of a major transcription start site and determined their effects on driving expression of the luciferase reporter gene in transfected hematopoietic cell lines. A region extending from nucleotides (nt) -302 to +19 was sufficient for cell-restricted and phorbol ester-inducible expression. DNase I footprinting of this region revealed two adjacent protected segments extending from nt -81 to -68 (box A) and -55 to -41 (box B). When a construct of 47 nt in length containing box A and box B and lacking other 3' or 5' elements was cloned into a promoterless vector, it conferred tissue-specific and phorbol ester-inducible expression. Gel retardation revealed that the protein components of two major protein-DNA complexes that form on both box A and box B and are required for transcriptional activation are members of the Ets oncoprotein family; one is related to the GA-binding protein (GABP), and the other is related to PU.1/Spi-1. The minimal CD18 promoter, lacking TATA, CAAT, and initiator elements and consisting primarily of Ets repeats, may exemplify an emerging class of promoters with which the concerted binding of Ets factors is necessary and sufficient to mediate transcriptional activation through direct recruitment of the basal transcription machinery.
Collapse
Affiliation(s)
- E P Böttinger
- Department of Medicine, Harvard Medical School, Charlestown, Massachusetts
| | | | | | | |
Collapse
|
26
|
Böttinger EP, Niles JL, Collins AB, McCluskey RT, Arnaout MA. Antineutrophil cytoplasmic autoantibody-associated vasculitis presenting as Sjögren's syndrome. Arthritis Rheum 1992; 35:1373-6. [PMID: 1445456 DOI: 10.1002/art.1780351120] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A 63-year-old woman, in whom a diagnosis of Sjögren's syndrome was initially made, proved to have systemic vasculitis with salivary gland involvement and necrotizing and crescentic glomerulonephritis. Antineutrophil cytoplasmic autoantibodies (ANCA) against myeloperoxidase were positive. ANCA-associated vasculitis should be considered in the differential diagnosis of Sjögren's syndrome. A positive finding on immunoassay for ANCA against myeloperoxidase or proteinase 3 may help establish the diagnosis.
Collapse
Affiliation(s)
- E P Böttinger
- Leukocyte Biology and Inflammation Program, Massachusetts General Hospital, Harvard Medical School, Boston 02129
| | | | | | | | | |
Collapse
|