scholarly journals Transforming growth factor-beta complexes with thrombospondin.

1992 ◽  
Vol 3 (2) ◽  
pp. 181-188 ◽  
Author(s):  
J E Murphy-Ullrich ◽  
S Schultz-Cherry ◽  
M Höök
Keyword(s):  
Growth Factor ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Neutralizing Antibody ◽  
Gel Permeation Chromatography ◽  
Soft Agar ◽  
Biologically Active ◽  
Dependent Manner ◽  
Tgf Beta ◽  
Growth Factor Beta

Thrombospondin (TSP) was demonstrated to inhibit the growth of bovine aortic endothelial cells, an activity that was not neutralized by antibodies to TSP or by other agents that block TSP-cell interactions but that partially was reversed by a neutralizing antibody to transforming growth factor-beta (TGF-beta). Similar to TGF-beta, TSP supported the growth of NRK-49F colonies in soft agar in a dose-dependent manner, which required epidermal growth factor and was neutralized by anti-TGF-beta antibody. Chromatography of a TSP preparation did not separate the TGF-beta-like NRK colony-forming activity from high molecular weight protein. However, when chromatography was performed at pH 11, this activity was dissociated from TSP. These results suggest that at least some growth modulating activities of TSP are due to TGF-beta associated with TSP by strong non-covalent forces. Most of the active TGF-beta released from platelets after degranulation was associated with TSP, as demonstrated by anti-TSP immunoaffinity and gel permeation chromatography. 125I-TGF-beta binds to purified TSP in an interaction that is specific in the sense that bound TGF-beta could be displaced by TGF-depleted TSP but not significantly by native TSP, heparin, decorin, alpha 2-macroglobulin, fibronectin, or albumin. Hence, TGF-beta can bind to TSP, and the complex forms under physiological conditions. Furthermore, TSP-associated TGF-beta is biologically active, and the binding of TGF-beta to TSP may protect TGF-beta from extracellular inactivators.

scholarly journals Transforming growth factor beta 1 (TGF-beta 1) induced neutrophil recruitment to synovial tissues: implications for TGF-beta-driven synovial inflammation and hyperplasia.

1991 ◽  
Vol 173 (5) ◽  
pp. 1121-1132 ◽  
Author(s):  
R A Fava ◽  
N J Olsen ◽  
A E Postlethwaite ◽  
K N Broadley ◽  
J M Davidson ◽  
...  
Keyword(s):  
Growth Factor ◽  
Synovial Tissue ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Biologically Active ◽  
Tgf Beta ◽  
Histological Techniques ◽  
Growth Factor Beta

We have studied the consequences of introducing human recombinant transforming growth factor beta 1 (hrTGF-beta 1) into synovial tissue of the rat, to begin to better understand the significance of the fact that biologically active TGF-beta is found in human arthritic synovial effusions. Within 4-6 h after the intra-articular injection of 1 microgram of hrTGF-beta 1 into rat knee joints, extensive recruitment of polymorphonuclear leukocytes (PMNs) was observed. Cytochemistry and high resolution histological techniques were used to quantitate the influx of PMNs, which peaked 6 h post-injection. In a Boyden chamber assay, hrTGF-beta 1 at 1-10 fg/ml elicited a chemotactic response from PMNs greater in magnitude than that evoked by FMLP, establishing that TGF-beta 1 is an effective chemotactic agent for PMNs in vitro as well as in vivo. That PMNs may represent an important source of TGF-beta in inflammatory infiltrates was strongly suggested by a demonstration that stored TGF-beta 1 was secreted during phorbol myristate acetate-stimulated degranulation in vitro. Acid/ethanol extracts of human PMNs assayed by ELISA contained an average of 355 ng of TGF/beta 1 per 10(9) cells potentially available for secretion during degranulation of PMNs. [3H]Thymidine incorporation in vivo and autoradiography of tissue sections revealed that widespread cell proliferation was triggered by TGF-beta 1 injection. Synovial lining cells and cells located deep within the subsynovial connective tissue were identified as sources of at least some of the new cells that contribute to TGF-beta 1-induced hyperplasia. Our results demonstrate that TGF-beta is capable of exerting pathogenic effects on synovial tissue and that PMNs may represent a significant source of the TGF-beta present in synovial effusions.

Expression and secretion of transforming growth factor-beta by bleomycin-stimulated rat alveolar macrophages

1993 ◽  
Vol 264 (1) ◽  
pp. L36-L42 ◽  
Author(s):  
E. M. Denholm ◽  
S. M. Rollins
Keyword(s):  
Growth Factor ◽  
Alveolar Macrophages ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Chemotactic Activity ◽  
Beta Activity ◽  
Dependent Manner ◽  
Tgf Beta ◽  
Growth Factor Beta

Bleomycin-induced fibrosis in rodents has been used extensively as a model of human pulmonary fibrosis. The influx of monocytes observed during the early stages of fibrosis is at least partially regulated by the elaboration of chemotactic factors in the lung. Exposure of alveolar macrophages (AM phi) to bleomycin either in vivo or in vitro stimulated secretion of monocyte chemotactic activity (MCA). This MCA has been previously characterized as being primarily due to fibronectin fragments. The present experiments revealed that bleomycin also induced AM phi to secrete a second chemotactic factor, transforming growth factor-beta (TGF-beta). However, the TGF-beta secreted by macrophages was in latent form, since no TGF-beta activity was detected unless AM phi conditioned medium (CM) was acid-activated. After acidification, chemotactic activity in CM from AM phi stimulated with bleomycin in vitro was increased by 3.6, whereas activity in AM phi CM from fibrotic rats increased by 2 and that of a bleomycin-stimulated AM phi cell line increased by 1.6. This acid-activatable chemotactic activity was inhibited by antibody to TGF-beta. Bleomycin-stimulated AM phi s secreted significantly more TGF-beta than did unstimulated controls. Further, in vitro exposure of AM phi to bleomycin induced TGF-beta mRNA expression in a time- and concentration-dependent manner, with maximal mRNA being detected following a 16-h incubation with 1 microgram/ml bleomycin.

scholarly journals Transforming growth factor beta abrogates the effects of hematopoietins on eosinophils and induces their apoptosis.

1994 ◽  
Vol 179 (3) ◽  
pp. 1041-1045 ◽  
Author(s):  
R Alam ◽  
P Forsythe ◽  
S Stafford ◽  
Y Fukuda
Keyword(s):  
Growth Factor ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Dependent Manner ◽  
Tgf Beta ◽  
Gm Csf ◽  
Eosinophil Survival ◽  
Growth Factor Beta ◽  
Induced Apoptosis ◽  
And Function

Hematopoietins, interleukin (IL)-3, IL-5, and granulocyte/macrophage colony-stimulating factor (GM-CSF) have previously been shown to prolong eosinophil survival and abrogate apoptosis. The objective of this study was to investigate the effect of transforming growth factor beta (TGF-beta) on eosinophil survival and apoptosis. Eosinophils from peripheral blood of mildly eosinophilic donors were isolated to > 97% purity using discontinuous Percoll density gradient. Eosinophils were cultured with hematopoietins with or without TGF-beta for 4 d and their viability was assessed. We confirmed previous observations that hematopoietins prolonged eosinophil survival and inhibited apoptosis. TGF-beta at concentrations > or = 10(-12) M abrogated the survival-prolonging effects of hematopoietins in a dose-dependent manner and induced apoptosis as determined by DNA fragmentation in agarose gels. The effect of TGF-beta was blocked by an anti-TGF-beta antibody. The anti-TGF-beta antibody also prolonged eosinophil survival on its own. The culture of eosinophils with IL-3 and GM-CSF stimulated the synthesis of GM-CSF and IL-5, respectively, suggesting an autocrine mechanism of growth factor production. TGF-beta inhibited the synthesis of GM-CSF and IL-5 by eosinophils. TGF-beta did not have any effect on the expression of GM-CSF receptors on eosinophils. We also studied the effect of TGF-beta on eosinophil function and found that TGF-beta inhibited the release of eosinophil peroxidase. Thus, TGF-beta seems to inhibit eosinophil survival and function. The inhibition of endogenous synthesis of hematopoietins may be one mechanism by which TGF-beta blocks eosinophil survival and induces apoptosis.

scholarly journals Retinoic acid induces transforming growth factor-beta 2 in cultured keratinocytes and mouse epidermis.

1989 ◽  
Vol 1 (1) ◽  
pp. 87-97 ◽  
Author(s):  
A B Glick ◽  
K C Flanders ◽  
D Danielpour ◽  
S H Yuspa ◽  
M B Sporn
Keyword(s):  
Retinoic Acid ◽  
Growth Factor ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Biologically Active ◽  
Tgf Beta ◽  
Mouse Epidermis ◽  
Cultured Keratinocytes ◽  
Growth Factor Beta ◽  
Beta 2

We have studied the functional interaction between retinoic acid and transforming growth factor-beta (TGF-beta), using the mouse epidermis as a model system. Treatment with retinoic acid increases expression of TGF-beta 2 in cultured keratinocytes in vitro, as well as in the epidermis in vivo. This TGF-beta 2 is secreted in a biologically active form that can bind to surface receptors, in contrast to most other conditions in which TGF-beta is secreted in a latent form. Specific antibodies to TGF-beta 2 partially reverse the ability of retinoic acid to inhibit DNA synthesis in cultured keratinocytes. The regulation of TGF-beta 2 expression by retinoic acid may have important physiological and pharmacological roles in the maintenance of epidermal homeostasis.

scholarly journals Proteolytic activation of latent transforming growth factor-beta from fibroblast-conditioned medium.

1988 ◽  
Vol 106 (5) ◽  
pp. 1659-1665 ◽  
Author(s):  
R M Lyons ◽  
J Keski-Oja ◽  
H L Moses
Keyword(s):  
Growth Factor ◽  
Conditioned Medium ◽  
Transforming Growth Factor Beta ◽  
Acid Treatment ◽  
Transforming Growth Factor ◽  
Soft Agar ◽  
Tgf Beta ◽  
Growth Factor Beta ◽  
Mild Acid ◽  
Cell Conditioned Medium

Transforming growth factor-beta (TGF beta) is produced by most cultured cells in an inactive form. Potential activation mechanisms of latent TGF beta were studied using fibroblastic (NRK-49F and AKR-MCA) cell-conditioned medium as a model. Active TGF beta was monitored by radioreceptor and soft agar assays as well as by antibody inhibition and immunoprecipitation. Little or no TGF beta was detected in untreated conditioned medium. Treatment of the medium with extremes of pH (1.5 or 12) resulted in significant activation of TGF beta as shown by radioreceptor assays, while mild acid treatment (pH 4.5) yielded only 20-30% of the competition achieved by pH 1.5. In an effort to define more physiological means of TGF beta activation, the effects of some proteases were tested. Plasmin and cathepsin D were found to generate 25-kD bands corresponding to the active form of TGF beta as shown by immunoprecipitation analysis of radiolabeled cell-conditioned medium. Plasmin treatment of the medium resulted in activity that was quantitatively similar to that of mild acid treatment as measured by radioreceptor and soft agar assays. In addition, the plasmin-generated activity was inhibited by anti-TGF beta antibodies. Sequential treatments of AKR-MCA cell-conditioned medium with mild acid followed by plasmin or plasmin followed by mild acid gave activation comparable to either treatment alone. The data suggest that conditioned medium may contain at least two different pools of latent TGF beta. One pool is resistant to mild acid and/or plasmin and requires strong acid or alkali treatment for activation. A second pool is activated by mild pH change and/or plasmin. Activation of this form of latent TGF beta may take place by dissociation or proteolytic digestion from a precursor molecule or hypothetical TGF beta-binding protein complex.

Cytokine signaling in lung: transforming growth factor-beta secretion by lung fibroblasts

1991 ◽  
Vol 260 (2) ◽  
pp. L123-L128 ◽  
Author(s):  
J. Kelley ◽  
J. P. Fabisiak ◽  
K. Hawes ◽  
M. Absher
Keyword(s):  
Growth Factor ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Phenotypic Expression ◽  
Soft Agar ◽  
Lung Fibroblast ◽  
Lung Fibroblasts ◽  
Tgf Beta ◽  
Anchorage Independent Growth ◽  
Growth Factor Beta

Control of growth and phenotypic expression of interstitial fibroblasts is a critical determinant of lung architecture and physiology during processes of growth and remodeling. We examined the ability of lung fibroblasts to produce transforming growth factor-beta (TGF-beta), a cytokine that is known to modulate proliferation and phenotypic expression of mesenchymal cells. Cultures of fibroblasts isolated from rat lungs spontaneously secrete TGF-beta as measured in the standard bioassay of anchorage-independent growth of normal rat kidney (NRK) cells in soft agar. Rat lung fibroblasts secrete TGF-beta in an inactive precursor form. Fibroblasts cultured from adult and fetal rat lungs produced comparable amounts of TGF-beta. The ability of lung fibroblast supernatant fluids to induce colony formation in soft agar could be completely neutralized by preincubation of samples with anti-TGF-beta immunoglobulin (Ig). Anti-platelet-derived growth factor IgG had no effect on anchorage-independent growth of NRK cells driven by rat fibroblast culture supernatant samples. These results indicate that TGF-beta does not require the presence of and interaction with secondary cytokines for its activity. In contrast to the results obtained with rat cells, neither human fetal nor adult lung fibroblasts secreted detectable amount of active TGF-beta or its inactive precursor. This was not due to the presence of TGF-beta inhibitors in fibroblast culture media, because the addition of purified porcine TGF-beta to conditioned medium from human lung fibroblast cultures yielded the expected increase in NRK cell growth in soft agar. These results point to differing cytokine control patterns in the lungs of the two species.

scholarly journals Human natural killer cell expansion is regulated by thrombospondin- mediated activation of transforming growth factor-beta 1 and independent accessory cell-derived contact and soluble factors

Blood ◽  
1996 ◽  
Vol 87 (1) ◽  
pp. 180-189 ◽  
Author(s):  
BA Pierson ◽  
K Gupta ◽  
WS Hu ◽  
JS Miller
Keyword(s):  
Growth Factor ◽  
Transforming Growth Factor Beta ◽  
Direct Contact ◽  
Transforming Growth Factor ◽  
Neutralizing Antibody ◽  
Accessory Cell ◽  
Tgf Beta ◽  
Soluble Factors ◽  
Marrow Stroma ◽  
Growth Factor Beta

Natural killer cells (NK) were studied to determine factors important in their expansion. Flourescence-activated cell sorter (FACS) purified CD56+/CD3- NK cells cultured alone for 18 days in rIL-2 containing medium (1,000 U/mL) showed enhanced cytotoxicity but only minimal expansion. NK expansion was increased (12.5 +/- 1.6-fold) by coculturing NK with soluble factors produced by irradiated peripheral blood mononuclear cells (PBMNC) in which the two populations were separated by a microporous membrane. However, maximal NK expansion was always observed when NK were cocultured in direct contact with irradiated PBMNC (49.4 +/- 5.9-fold). To determine if marrow stroma, which supports differentiation of primitive NK progenitors, was a better accessory cell population than irradiated PBMNC, NK were cocultured in direct contact with primary marrow stromal layers. NK expansion with marrow stroma was similar to PBMNC. Fibroblast cell lines (M2–10B4, NRK-49F, NIH-3T3) and human umbilical vein endothelial cells (HUVEC), all homogeneous populations and devoid of monocytes, also exhibited a similar contact-dependent increase in NK expansion. Experiments were designed using fixed M2–10B4 stromal cells to separate the contact-induced proliferative stimuli from soluble factors. NK plated directly on ethanol/acetic acid-fixed M2–10B4, which leaves stromal ligands (cell membrane components and ECM) intact, resulted in increased NK expansion compared with medium alone. We further show that the combination of independent contact and soluble factors is responsible for maximal late NK expansion (days 28 through 40) but paradoxically inhibits early NK expansion (day 7). The proliferation inhibitory effects were verified by 3H-thymidine uptake and could be detected at days 2 through 6 but no longer 14 days after the initiation of the culture. We show that both laminin and thrombospondin inhibit early NK proliferation, whereas only thrombospondin was capable of also stimulating late NK expansion. The effect of thrombospondin on early NK proliferation is related to activation of transforming growth factor-beta 1 (TGF-beta) because anti-TGF-beta neutralizing antibody completely abrogated thrombospondin-mediated inhibition of early NK proliferation. Although inhibitory early in culture, active TGF-beta added only at culture initiation increases late NK expansion similar to thrombospondin. TGF-beta was not present in the thrombospondin preparation but latent TGF-beta in serum, or TGF-beta transcripts identified in IL-2-activated NK could explain paracrine or autocrine mechanisms for the regulation of NK proliferation. Finally, anti-TGF-beta neutralizing antibody only minimally affects stroma-mediated inhibition of early NK proliferation suggesting that aside from thrombospondin/TGF-beta, additional contact factors are important for the regulation of NK proliferation.

scholarly journals Transforming growth factor beta inhibits megakaryocyte growth and endomitosis

Blood ◽  
1992 ◽  
Vol 79 (3) ◽  
pp. 619-626 ◽  
Author(s):  
DJ Kuter ◽  
DM Gminski ◽  
RD Rosenberg
Keyword(s):  
Growth Factor ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Potent Inhibitor ◽  
Neutralizing Antibody ◽  
Maximal Concentration ◽  
Tgf Beta ◽  
Inhibitory Effects ◽  
Growth Factor Beta

Abstract Using a rat bone marrow culture system, the effect of transforming growth factor beta 1 (TGF beta 1) on megakaryocyte growth and endoreduplication has been studied. Purified human platelet TGF beta 1 inhibited the number of megakaryocytes that appeared in culture at a half-maximal concentration of 0.66 +/- 0.21 ng/mL and inhibited megakaryocyte endoreduplication at a half-maximal concentration of 0.14 +/- 0.08 ng/mL. Under identical conditions, growth of erythroid precursors was half-maximally inhibited at a concentration of 0.125 ng/mL while myeloid growth was not inhibited at concentrations of TGF beta 1 up to 25 ng/mL. These profound inhibitory effects on megakaryocyte growth and endomitosis suggested that TGF beta might play a role in megakaryocytopoiesis. Therefore, we explored the effect of TGF beta in three different experimental situations by using a neutralizing antibody to TGF beta: (1) Serum but not plasma was found to inhibit the number and ploidy of megakaryocytes that grew in vitro. This inhibitory activity was completely neutralized by antibody to TGF beta or on treatment with dithiothreitol. (2) Plasma from thrombocytotic rats was observed to decrease megakaryocyte ploidy on culture but this effect was not prevented by the addition of antibody to TGF beta. (3) Plasma from thrombocytopenic but not normal rats increased megakaryocyte ploidy on culture. Addition of antibody to TGF beta did not alter these results. Therefore, TGF beta is a potent inhibitor of the number and ploidy of megakaryocytes and accounts for all the inhibition seen when megakaryocytes are cultured in serum. However, the differences in effect on megakaryocyte growth that we observe between normal, thrombocytopenic, and thrombocytotic plasmas are not due to variations in the amount of TGF beta. Furthermore, our results show that release of TGF beta from megakaryocytes during culture does not act as an autocrine regulator of megakaryocyte ploidy in vitro.

scholarly journals Quercetin inhibits the growth of leukemic progenitors and induces the expression of transforming growth factor-beta 1 in these cells

Blood ◽  
1995 ◽  
Vol 85 (12) ◽  
pp. 3654-3661 ◽  
Author(s):  
LM Larocca ◽  
L Teofili ◽  
S Sica ◽  
M Piantelli ◽  
N Maggiano ◽  
...  
Keyword(s):  
Growth Factor ◽  
Transforming Growth Factor Beta ◽  
Inhibitory Activity ◽  
Transforming Growth Factor ◽  
Dependent Manner ◽  
Tgf Beta ◽  
Acute Leukemias ◽  
Growth Inhibitory ◽  
Growth Inhibitory Activity ◽  
Growth Factor Beta

We previously showed that quercetin (3,3′,4′,5,7 pentahydroxyflavone) inhibits in a dose-dependent manner the growth of acute leukemias and is able to enhance the antiproliferative activity of cytosine arabinoside. We show here that quercetin inhibits the clonogenic activity of 20 of 22 acute leukemias (AL; 4 M1-AML, 3 M2-AML, 2 M3-AML, 3 M4-AML, 3 M5-AML, and 7 ALL). In the present report, we show that the induction of transforming growth factor-beta 1 (TGF-beta 1) in leukemic blasts is one of the growth-inhibitory mechanisms of quercetin in these cells. This observation was supported by the following data. (1) Quercetin-sensitive leukemic blasts, when treated with quercetin, secrete large amounts of TGF-beta 1 in the medium and show positivity for TGF-beta 1-immunoreactive material in the cytoplasm. (2) At a concentration of 8 mumol/L, antisense TGF-beta 1 oligonucleotides prevent the growth-inhibitory action of quercetin. (3) Anti-TGF-beta 1 neutralizing monoclonal antibodies can prevent almost completely the growth-inhibitory activity of quercetin. The analysis of quercetin-resistant cases confirmed as well the central role of TGF-beta 1 in the growth-inhibitory activity of quercetin. In conclusion, quercetin can act as a cytostatic agent for leukemic cells by modulating the production of TGF-beta 1.

scholarly journals Transforming growth factor-beta activity is potentiated by heparin via dissociation of the transforming growth factor-beta/alpha 2-macroglobulin inactive complex.

1989 ◽  
Vol 109 (1) ◽  
pp. 441-448 ◽  
Author(s):  
T A McCaffrey ◽  
D J Falcone ◽  
C F Brayton ◽  
L A Agarwal ◽  
F G Welt ◽  
...  
Keyword(s):  
Biological Activity ◽  
Growth Factor ◽  
Transforming Growth Factor Beta ◽  
Transforming Growth Factor ◽  
Biologically Active ◽  
Antiproliferative Effect ◽  
Tgf Beta ◽  
Binding Studies ◽  
Growth Inhibitory ◽  
Growth Factor Beta

The control of smooth muscle cell (SMC) proliferation is determined by the combined actions of mitogens, such as platelet-derived growth factor, and the opposing action of growth inhibitory agents, such as heparin and transforming growth factor-beta (TGF-beta). The present studies identify an interaction between heparin and TGF-beta in which heparin potentiates the biological action of TGF-beta. Using a neutralizing antibody to TGF-beta, we observed that the short term antiproliferative effect of heparin depended upon the presence of biologically active TGF-beta. This effect was observed in rat and bovine aortic SMC and in CCL64 cells, but not in human saphenous vein SMC. Binding studies demonstrated that the addition of heparin (100 micrograms/ml) to medium containing 10% plasma-derived serum resulted in a 45% increase in the specific binding of 125I-TGF-beta to cells. Likewise, heparin induced a twofold increase in the growth inhibitory action of TGF-beta at concentrations of TGF-beta near its apparent dissociation constant. Using 125I-labeled TGF-beta, we demonstrated that TGF-beta complexes with the plasma component alpha 2-macroglobulin, but not with fibronectin. Heparin increases the electrophoretic mobility of TGF-beta apparently by freeing TGF-beta from its complex with alpha 2-macroglobulin. Dextran sulfate, another highly charged antiproliferative molecule, but not chondroitin sulfate or dermatan sulfate, similarly modified TGF-beta's mobility. Relatively high, antiproliferative concentrations of heparin (1-100 micrograms/ml) were required to dissociate the TGF-beta/alpha 2-macroglobulin complex. Thus, it appears that the antiproliferative effect of heparin may be partially attributed to its ability to potentiate the biological activity of TGF-beta by dissociating it from alpha 2-macroglobulin, which normally renders it inactive. We suggest that heparin-like agents may be important regulators of TGF-beta's biological activity.

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