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

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.

Blood ◽  
1996 ◽  
Vol 87 (1) ◽  
pp. 180-189 ◽  
Author(s):  
BA Pierson ◽  
K Gupta ◽  
WS Hu ◽  
JS Miller

Abstract 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.


Blood ◽  
1992 ◽  
Vol 79 (3) ◽  
pp. 619-626 ◽  
Author(s):  
DJ Kuter ◽  
DM Gminski ◽  
RD Rosenberg

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.


Blood ◽  
1992 ◽  
Vol 79 (3) ◽  
pp. 619-626 ◽  
Author(s):  
DJ Kuter ◽  
DM Gminski ◽  
RD Rosenberg

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.


1993 ◽  
Vol 121 (2) ◽  
pp. 439-448 ◽  
Author(s):  
S Kojima ◽  
K Nara ◽  
D B Rifkin

A hitherto unknown function for transglutaminase (TGase; R-glutaminyl-peptide: amine gamma-glutamyltransferase, EC 2.3.2.13) was found in the conversion of latent transforming growth factor-beta (LTGF-beta) to active TGF-beta by bovine aortic endothelial cells (BAECs). The cell-associated, plasmin-mediated activation of LTGF-beta to TGF-beta induced either by treatment of BAECs with retinoids or by cocultures of BAECs and bovine smooth muscle cells (BSMCs) was blocked by seven different inhibitors of TGase as well as a neutralizing antibody to bovine endothelial cell type II TGase. Control experiments indicated that TGase inhibitors and/or a neutralizing antibody to TGase did not interfere with the direct action of TGF-beta, the release of LTGF-beta from cells, or the activation of LTGF-beta by plasmin or by transient acidification. After treatment with retinoids, BAECs expressed increased levels of TGase coordinate with the generation of TGF-beta, whereas BSMCs and bovine embryonic skin fibroblasts, which did not activate LTGF-beta after treatment with retinoids, did not. Furthermore, both TGase inhibitors and a neutralizing antibody to TGase potentiated the effect of retinol in enhancing plasminogen activator (PA) levels in cultures of BAECs by suppressing the TGF-beta-mediated enhancement of PA inhibitor-1 (PAI-1) expression. These results indicate that type II TGase is a component required for cell surface, plasmin-mediated LTGF-beta activation process and that increased expression of TGase accompanies retinoid-induced activation of LTGF-beta.


1992 ◽  
Vol 3 (2) ◽  
pp. 181-188 ◽  
Author(s):  
J E Murphy-Ullrich ◽  
S Schultz-Cherry ◽  
M Höök

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.


1993 ◽  
Vol 177 (1) ◽  
pp. 225-230 ◽  
Author(s):  
S M Wahl ◽  
J B Allen ◽  
G L Costa ◽  
H L Wong ◽  
J R Dasch

Transforming growth factor beta (TGF-beta) induces leukocyte recruitment and activation, events central to an inflammatory response. In this study, we demonstrate that antagonism of TGF-beta with a neutralizing antibody not only blocks inflammatory cell accumulation, but also tissue pathology in an experimental model of chronic erosive polyarthritis. Intraarticular injection of monoclonal antibody 1D11.16, which inhibits both TGF-beta 1 and TGF-beta 2 bioactivity, into animals receiving an arthropathic dose of bacterial cell walls significantly inhibits arthritis. Inhibition was observed with a single injection of 50 micrograms antibody, and a 1-mg injection blocked acute inflammation > 75% compared with the contralateral joints injected with an irrelevant isotype control antibody (MOPC21) as quantitated by an articular index (AI = 0.93 +/- 0.23 for 1D11.16, and AI = 4.0 +/- 0 on day 4; p < 0.001). Moreover, suppression of the acute arthritis achieved with a single injection of antibody was sustained into the chronic, destructive phase of the disease (on day 18, AI = 0.93 +/- 0.07 vs. AI = 2.6 +/- 0.5; p < 0.01). The decreased inflammatory index associated with anti-TGF-beta treatment was consistent with histopathologic and radiologic evidence of a therapeutic response. These data implicate TGF-beta as a profound agonist not only in the early events responsible for synovial inflammation, but also in the chronicity of streptococcal cell wall fragment-induced inflammation culminating in destructive pathology. Interrupting the cycle of leukocyte recruitment and activation with TGF-beta antagonists may provide a mechanism for resolution of chronic destructive lesions.


1990 ◽  
Vol 265 (2) ◽  
pp. 1089-1093 ◽  
Author(s):  
P Kondaiah ◽  
M J Sands ◽  
J M Smith ◽  
A Fields ◽  
A B Roberts ◽  
...  

1988 ◽  
Vol 8 (5) ◽  
pp. 2229-2232 ◽  
Author(s):  
A M Brunner ◽  
L E Gentry ◽  
J A Cooper ◽  
A F Purchio

Analyses of cDNA clones coding for simian type 1 transforming growth factor beta (TGF-beta 1) suggest that there are three potential sites for N-linked glycosylation located in the amino terminus of the precursor region. Analysis of [3H]glucosamine-labeled serum-free supernatants from a line of Chinese hamster ovary cells which secrete high levels of recombinant TGF-beta 1 indicate that the TGF-beta 1 precursor, but not the mature form, is glycosylated. Digestion with neuraminidase resulted in a shift in migration of the two TGF-beta 1 precursor bands, which suggests that they contain sialic acid residues. Endoglycosidase H had no noticeable effect. Treatment with N-glycanase produced two faster-migrating sharp bands, the largest of which had a molecular weight of 39 kilodaltons. TGF-beta 1-specific transcripts produced by SP6 polymerase programmed the synthesis of a 42-kilodalton polypeptide which, we suggest, is the unmodified protein backbone of the precursor. Labeling with 32Pi showed that the TGF-beta 1 precursor was phosphorylated in the amino portion of the molecule.


1991 ◽  
Vol 173 (3) ◽  
pp. 589-597 ◽  
Author(s):  
G Poli ◽  
A L Kinter ◽  
J S Justement ◽  
P Bressler ◽  
J H Kehrl ◽  
...  

The pleiotropic immunoregulatory cytokine transforming growth factor beta (TGF-beta) potently suppresses production of the human immunodeficiency virus (HIV), the causative agent of the acquired immunodeficiency syndrome, in the chronically infected promonocytic cell line U1. TGF-beta significantly (50-90%) inhibited HIV reverse transcriptase production and synthesis of viral proteins in U1 cells stimulated with phorbol myristate acetate (PMA) or interleukin 6 (IL-6). Furthermore, TGF-beta suppressed PMA induction of HIV transcription in U1 cells. In contrast, TGF-beta did not significantly affect the expression of HIV induced by tumor necrosis factor alpha (TNF-alpha). These suppressive effects were not mediated via the induction of interferon alpha (IFN-alpha). TGF-beta also suppressed HIV replication in primary monocyte-derived macrophages infected in vitro, both in the absence of exogenous cytokines and in IL-6-stimulated cultures. In contrast, no significant effects of TGF-beta were observed in either a chronically infected T cell line (ACH-2) or in primary T cell blasts infected in vitro. Therefore, TGF-beta may play a potentially important role as a negative regulator of HIV expression in infected monocytes or tissue macrophages in infected individuals.


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