Transforming growth factor-β–induced protein (TGFBIp/β ig-h3) activates platelets and promotes thrombogenesis

Blood ◽  
2009 ◽  
Vol 114 (25) ◽  
pp. 5206-5215 ◽  
Author(s):  
Ha-Jeong Kim ◽  
Pan-Kyung Kim ◽  
Sang Mun Bae ◽  
Hye-Nam Son ◽  
Debraj Singh Thoudam ◽  
...  
Keyword(s):  
Pulmonary Embolism ◽  
Growth Factor ◽  
Platelet Activation ◽  
Matrix Protein ◽  
Transforming Growth Factor ◽  
Thrombus Formation ◽  
Transforming Growth Factor Β ◽  
Extracellular Matrix Protein ◽  
Type I

Abstract Transforming growth factor-β–induced protein (TGFBIp)/βig-h3 is a 68-kDa extracellular matrix protein that is functionally associated with the adhesion, migration, proliferation, and differentiation of various cells. The presence of TGFBIp in platelets led us to study the role of this protein in the regulation of platelet functions. Upon activation, platelet TGFBIp was released and associated with the platelets. TGFBIp mediates not only the adhesion and spread of platelets but also activates them, resulting in phosphatidylserine exposure, α-granule secretion, and increased integrin affinity. The fasciclin 1 domains of TGFBIp are mainly responsible for the activation of platelets. TGFBIp promotes thrombus formation on type I fibrillar collagen under flow conditions in vitro and induces pulmonary embolism in mice. Moreover, transgenic mice, which have approximately a 1.7-fold greater blood TGFBIp concentration, are significantly more susceptible to collagen- and epinephrine-induced pulmonary embolism than wild-type mice. These results suggest that TGFBIp, a human platelet protein, plays important roles in platelet activation and thrombus formation. Our findings will increase our understanding of the novel mechanism of platelet activation, contributing to a better understanding of thrombotic pathways and the development of new antithrombotic therapies.

Expression of Transforming Growth Factor-β by Human Islets: Impact on Islet Viability and Function

2007 ◽  
Vol 16 (8) ◽  
pp. 775-785 ◽  
Author(s):  
Omaima M. Sabek ◽  
Daniel W. Fraga ◽  
James Henry ◽  
Lillian W. Gaber ◽  
Malak Kotb ◽  
...  
Keyword(s):  
Growth Factor ◽  
Matrix Protein ◽  
Transforming Growth Factor ◽  
Active Form ◽  
Transforming Growth Factor Β ◽  
Human Islets ◽  
Extracellular Matrix Protein ◽  
Tgf Β1

Transforming growth factor-β1 (TGF-β1) is a pleotropic cytokine that promotes angiogenesis and extracellular matrix protein synthesis in addition to its immunosuppressive effects. The purpose of this study is to identify optimal conditions for in vivo expression of TGF-β1 by human islets to exploit the possible beneficial effects and minimize undesirable side effects. We transduced human islets with adenoviral vectors encoding the active form of Ad-TGF-β1 or Ad-LacZ to test the effects of TGF-β1 gene expression on islet in vivo function following their transplantation into a NOD-SCID mouse model. Islets were transduced with multiplicity of infection (MOI) of 20, 10, 5, and 2.5 per islet cell. At a MOI ranging from 2.5 to 20, expression of TGF-β1 in islet supernatant persisted for 1–2 months and ranged from 153 ± 5 to 2574 ± 1299 pg/ml, respectively. Transduction with the lowest MOI (2.5) did not compromise the in vivo production of human C-peptide. We conclude that TGF-β1 expression in transplanted islets does not compromise viability and that adenoviral transduction with the TGF-β1 gene has a dose-dependent effect, with larger MOIs being deleterious. The data also indicate that in vitro culture system and the in vivo NOD-SCID model could be used successfully to evaluate the nonimmune effects of gene transduction.

Abstract 17285: A Selective Transforming Growth Factor-β and Growth Differentiation Factor-15 Ligand Trap Attenuates Pulmonary Hypertension

Circulation ◽  
2014 ◽  
Vol 130 (suppl_2) ◽  
Author(s):  
Lai-Ming Yung ◽  
Samuel D Paskin-Flerlage ◽  
Ivana Nikolic ◽  
Scott Pearsall ◽  
Ravindra Kumar ◽  
...  
Keyword(s):  
Growth Factor ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β ◽  
Type I ◽  
Rna Seq ◽  
Differentiation Factor ◽  
Group I ◽  
Tgf Β1

Introduction: Excessive Transforming Growth Factor-β (TGF-β) signaling has been implicated in pulmonary arterial hypertension (PAH), based on activation of TGF-β effectors and transcriptional targets in affected lungs and the ability of TGF-β type I receptor (ALK5) inhibitors to improve experimental PAH. However, clinical use of ALK5 inhibitors has been limited by cardiovascular toxicity. Hypothesis: We tested whether or not selective blockade of TGF-β and Growth Differentiation Factor (GDF) ligands using a recombinant TGFβ type II receptor extracellular domain Fc fusion protein (TGFBRII-Fc) could impact experimental PAH. Methods: Male SD rats were injected with monocrotaline (MCT) and received vehicle or TGFBRII-Fc (15 mg/kg, twice per week, i.p.). C57BL/6 mice were treated with SU-5416 and hypoxia (SUGEN-HX) and received vehicle or TGFBRII-Fc. RNA-Seq was used to profile transcriptional changes in lungs of MCT rats. Circulating levels of GDF-15 were measured in 241 PAH patients and 41 healthy controls. Human pulmonary artery smooth muscle cells were used to examine signaling in vitro . Results: TGFBRII-Fc is a selective ligand trap, inhibiting the ability of GDF-15, TGF-β1, TGF-β3, but not TGF-β2 to activate SMAD2/3 in vitro . In MCT rats, prophylactic treatment with TGFBRII-Fc normalized expression of TGF-β transcriptional target PAI-1, attenuated PAH and vascular remodeling. Delayed administration of TGFBRII-Fc in rats with established PAH at 2.5 weeks led to improved survival, decreased PAH and remodeling at 5 weeks. Similar findings were observed in SUGEN-HX mice. No valvular abnormalities were found with TGFBRII-Fc treatment. RNA-Seq revealed GDF-15 to be the most highly upregulated TGF-β ligand in the lungs of MCT rats, with only modest increases in TGF-β1 and no change in TGF-β2/3 observed, suggesting a dominant role of GDF-15 in the pathophysiology of this model. Plasma levels of GDF-15 were significantly increased in patients with diverse etiologies of WHO Group I PAH. Conclusions: These findings demonstrate that a selective TGF-β/GDF-15 trap attenuates experimental PAH, remodeling and mortality, without causing valvulopathy. These data highlight the potential role of GDF-15 as a pathogenic molecule and therapeutic target in PAH.

scholarly journals Identification of the growth factor–binding sequence in the extracellular matrix protein MAGP-1

2020 ◽  
Vol 295 (9) ◽  
pp. 2687-2697 ◽  
Author(s):  
Thomas J. Broekelmann ◽  
Nicholas K. Bodmer ◽  
Robert P. Mecham
Keyword(s):  
Extracellular Matrix ◽  
Growth Factor ◽  
Matrix Protein ◽  
Transforming Growth Factor ◽  
Cultured Cells ◽  
Transforming Growth Factor Β ◽  
Bmp Signaling ◽  
Extracellular Matrix Protein ◽  
Surface Plasmon Resonance Analysis ◽  
Factor Binding

Microfibril-associated glycoprotein-1 (MAGP-1) is a component of vertebrate extracellular matrix (ECM) microfibrils that, together with the fibrillins, contributes to microfibril function. Many of the phenotypes associated with MAGP-1 gene inactivation are consistent with dysregulation of the transforming growth factor β (TGFβ)/bone morphogenetic protein (BMP) signaling system. We have previously shown that full-length MAGP-1 binds active TGFβ-1 and some BMPs. The work presented here further defines the growth factor–binding domain of MAGP-1. Using recombinant domains and synthetic peptides, along with surface plasmon resonance analysis to measure the kinetics of the MAGP-1–TGFβ-1 interaction, we localized the TGFβ- and BMP-binding site in MAGP-1 to a 19-amino acid–long, highly acidic sequence near the N terminus. This domain was specific for binding active, but not latent, TGFβ-1. Growth factor activity experiments revealed that TGFβ-1 retains signaling activity when complexed with MAGP-1. Furthermore, when bound to fibrillin, MAGP-1 retained the ability to interact with TGFβ-1, and active TGFβ-1 did not bind fibrillin in the absence of MAGP-1. The absence of MAGP was sufficient to raise the amount of total TGFβ stored in the ECM of cultured cells, suggesting that the MAGPs compete with the TGFβ large latent complex for binding to microfibrils. Together, these results indicate that MAGP-1 plays an active role in TGFβ signaling in the ECM.

scholarly journals Transforming Growth Factor-β Receptors Interact with AP2 by Direct Binding to β2 Subunit

2002 ◽  
Vol 13 (11) ◽  
pp. 4001-4012 ◽  
Author(s):  
Diying Yao ◽  
Marcelo Ehrlich ◽  
Yoav I. Henis ◽  
Edward B. Leof
Keyword(s):  
Growth Factor ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β ◽  
Type I ◽  
Coated Pits ◽  
Wide Range ◽  
Cytoplasmic Tails ◽  
Direct Binding

Transforming growth factor-β (TGF-β) superfamily members regulate a wide range of biological processes by binding to two transmembrane serine/threonine kinase receptors, type I and type II. We have previously shown that the internalization of these receptors is inhibited by K+ depletion, cytosol acidification, or hypertonic medium, suggesting the involvement of clathrin-coated pits. However, the involvement of the clathrin-associated adaptor complex AP2 and the identity of the AP2 subunit that binds the receptors were not known. Herein, we have studied these issues by combining studies on intact cells with in vitro assays. Using fluorescence photobleaching recovery to measure the lateral mobility of the receptors on live cells (untreated or treated to alter their coated pit structure), we demonstrated that their mobility is restricted by interactions with coated pits. These interactions were transient and mediated through the receptors' cytoplasmic tails. To measure direct binding of the receptors to specific AP2 subunits, we used yeast two-hybrid screens and in vitro biochemical assays. In contrast to most other plasma membrane receptors that bind to AP2 via the μ2 subunit, AP2/TGF-β receptor binding was mediated by a direct interaction between the β2-adaptin N-terminal trunk domain and the cytoplasmic tails of the receptors; no binding was observed to the μ2, α, or ς2 subunits of AP2 or to μ1 of AP1. The data uniquely demonstrate both in vivo and in vitro the ability of β2-adaptin to directly couple TGF-β receptors to AP2 and to clathrin-coated pits, providing the first in vivo evidence for interactions of a transmembrane receptor with β2-adaptin.

Abstract 11021: Circulating Cardiac Transforming Growth Factor-β is a Principal Determinant in Inducing Myocardial Hypertrophy in Transgenic Mice Overexpressing Exogenous Hepatic Transforming Growth Factor-β

Circulation ◽  
2015 ◽  
Vol 132 (suppl_3) ◽  
Author(s):  
Shaukat A Khan ◽  
Takeshi Tsuda
Keyword(s):  
Growth Factor ◽  
Transgenic Mice ◽  
Matrix Protein ◽  
Transforming Growth Factor ◽  
Myocardial Hypertrophy ◽  
Cardiac Fibroblasts ◽  
Mrna Level ◽  
Transforming Growth Factor Β ◽  
Extracellular Matrix Protein ◽  
Potent Growth

Introduction: Transforming growth factor (TGF)-β is a potent growth factor that induces myocardial hypertrophy, but an interaction between circulating and myocardial TGF-β has been poorly understood. An extracellular matrix protein, fibulin-2, mediates exogenous TGF-β-induced endogenous TGF-β up-regulation in isolated cardiac fibroblasts. Hypothesis: Systemic TGF-β-induced myocardial hypertrophy is mediated primarily by enhanced myocardial TGF-β via paracrine fashion. Methods: We created double mutant mice with TGF-β1 over-expressing transgenic mice (TG) and fibulin-2 knockout mice (KO). TG developed myocardial hypertrophy due to excessive circulating hepatic TGF-β. We studied TGF-β dynamics between tissues and circulation during hypertrophic changes. Results: TG/WT developed significant myocardial hypertrophy at 8 weeks compared with non-TG (NTG) groups. Hypertrophy in TG/KO was significantly attenuated compared with TG/WT. Myocardial TGF-β mRNA level was significantly up-regulated in TG/WT compared with TG/KO or NGT groups, so was Smad2 activation, but myocardial TGF-β bioactivity was no different among all four groups. Serum carrier-bound TGF-β was significantly higher in TG/WT than in TG/KO or NTG groups, but free unbound TGF-β level was equally elevated in TG groups compared with NTG groups. Thus, hypertrophy in TG/WT may be attributed to increased serum carrier-bound TGF-β levels, not to either myocardial TGF-β activity or serum unbound TGF-β levels. Endogenous TGF-β mRNA level in kidney and liver was equally increased in TG group compared with NTG group, and was comparable in all 4 groups in lung, suggesting fibulin-2 was not involved in TGF-β-induced TGF-β synthesis in kidney, liver, or lung. Conclusions: Hepatic TGF-β-induced-myocardial TGF-β up-regulation was mediated by fibulin-2. In TG/WT, up-regulated myocardial TGF-β was mainly secreted into circulation as a soluble carrier-bound form and did not directly induce hypertrophy via paracrine fashion. It is this circulating endogenous myocardial TGF-β rather than transgene-induced hepatic TGF-β that is responsible for myocardial hypertrophy in TG/WT. Heart is a major endocrine organ in secreting circulating endogenous TGF-β in inducing myocardial hypertrophy.

scholarly journals Functionally diverse heteromeric traps for ligands of the transforming growth factor-β superfamily

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ravindra Kumar ◽  
Asya V. Grinberg ◽  
Huiming Li ◽  
Tzu-Hsing Kuo ◽  
Dianne Sako ◽  
...  
Keyword(s):  
Growth Factor ◽  
Transforming Growth Factor ◽  
Transforming Growth Factor Β ◽  
Type I ◽  
Systematic Analysis ◽  
Activin Receptor ◽  
Naturally Occurring ◽  
Functionally Diverse

AbstractLigands of the transforming growth factor-β (TGF-β) superfamily are important targets for therapeutic intervention but present challenges because they signal combinatorially and exhibit overlapping activities in vivo. To obtain agents capable of sequestering multiple TGF-β superfamily ligands with novel selectivity, we generated soluble, heterodimeric ligand traps by pairing the extracellular domain (ECD) of the native activin receptor type IIB (ActRIIB) alternately with the ECDs of native type I receptors activin receptor-like kinase 4 (ALK4), ALK7, or ALK3. Systematic analysis of these heterodimeric constructs by surface plasmon resonance, and comparison with their homodimeric counterparts, revealed that each type I receptor partner confers a distinct ligand-binding profile to the heterodimeric construct. Additional characterization in cell-based reporter gene assays confirmed that the heterodimeric constructs possessed different profiles of signaling inhibition in vitro, which translated into altered patterns of pharmacological activity when constructs were administered systemically to wild-type mice. Our results detail a versatile platform for the modular recombination of naturally occurring receptor domains, giving rise to inhibitory ligand traps that could aid in defining the physiological roles of TGF-β ligand sets or be directed therapeutically to human diseases arising from dysregulated TGF-β superfamily signaling.

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