Biomedical subjects

H G Remold

Publications and source records attributed to H G Remold.

At least 19 recordsLinked to original sources

PubMed1992

Macrophage colony-stimulating factor (CSF-1) enhances invasiveness in CSF-1 receptor-positive carcinoma cell lines.

We have identified two lung carcinoma cell lines, A549 and Calu-1, expressing low levels of the macrophage colony-stimulating factor (CSF-1) receptor (CSF-1R), encoded by the c-fms oncogene. The effect of CSF-1 on the invasive potential of these CSF-1R-positive tumor cell lines and on two other CSF-1R-bearing cell lines, the BT-20 breast carcinoma cell line and the CSF-1 growth-dependent murine macrophage cell line BAC1.2F5, was examined using a human amnionic basement membrane invasion model. Culture of A549, Calu-1, and BAC1.2F5 cells with CSF-1 (250 ng/ml) resulted in a maximal 12-, 5-, and 12-fold enhancement of invasion, respectively, compared to control cells cultured in medium alone. Larger concentrations of CSF-1 (750 ng/ml) reduced A549 and Calu-1 invasiveness compared to the effect of the 250-ng/ml dose. Maximal enhancement in invasion of A549 and Calu-1 cells occurred after a 24- and 48-h exposure to CSF-1, respectively. CSF-1 increased invasiveness 6-fold in BT-20 cells induced by glucocorticoids to express high levels of CSF-1R, in comparison to control cells not exposed to glucocorticoids or CSF-1. In contrast, CSF-1 had no effect on invasion in the CSF-1R-negative MCF-7 cell line. Culture of A549 and Calu-1 cells with other cytokines and growth factors including GM-CSF (500 units/ml), IL-3 (1 ng/ml), interferon-gamma (500 units/ml), and tumor necrosis factor (50 units/ml) had no significant effect on invasiveness. Thus, CSF-1 increases invasiveness in CSF-1R-positive tumor cell lines, suggesting a role in enhancing the metastatic potential of tumor cells expressing the CSF-1R.

Adenocarcinoma↗

PubMed1992

Endogenous receptor-bound urokinase mediates tissue invasion of the human lung carcinoma cell lines A549 and Calu-1.

Macrophage colony-stimulating factor (CSF-1) increases the tissue invasive potential of the CSF-1 receptor-bearing lung carcinoma cell lines A549 and Calu-1 by increasing the number of endogenously bound urokinase-type plasminogen activators (u-PA)s on these cells. CSF-1, at concentrations which optimize invasion of A549 and Calu-1 cells into human amnion membranes (250 ng/ml), maximally augments the number of u-PA receptors occupied by endogenously produced urokinase. Preincubation of A549 and Calu-1 cells with the anti-u-PA monoclonal antibody MPW5UK (25 micrograms/ml) or with a 20- to 40-fold stoichiometric excess of fluid phase type 2 plasminogen activator inhibitor abrogates invasiveness, indicating that functionally active cell surface u-PA is essential for tissue invasion. In contrast, fluid phase type 1 plasminogen activator inhibitor (PAI-1, 5-15 units/ml) does not inhibit invasiveness unless preincubated with the amnion membranes. Inhibition of invasion by PAI-1 is abolished by presaturating the amnion membranes with antiitronectin monoclonal antibody (10 micrograms/ml) which prevents binding of PAI-1 to tissue-associated vitronectin. Binding of PAI-1 to tissue vitronectin is therefore a prerequisite for its inhibitory action. Thus, endogenously receptor-bound u-PA is the primary protease mediating CSF-1-induced tissue invasiveness of the lung carcinoma cell lines A549 and Calu-1.

Amnion↗

PubMed1992

Interleukin-4 fails to inhibit interferon-gamma-induced activation of human colostral macrophages.

IL-4 abrogates the IFN-gamma-mediated activation of peripheral blood monocytes (M. Lehn, W. Y. Weiser, S. E. Engelhorn, S. Gillis, and H. G. Remold, 1989, J. Immunol. 143, 3020). In contrast, in colostral macrophages IL-4 fails to inhibit IFN-gamma-induced increase of H2O2 production and of antileishmanial activity. Flow cytometric analysis shows that the number of IL-4 receptors (IL-4R) is 2.4 times higher on colostral macrophages than on peripheral blood monocytes and that 23% of the colostral macrophages have detectable IL-4R in contrast to 2% of the blood monocytes. Thus, colostral macrophages are functionally different from peripheral blood monocytes in their response to IL-4 and in the numbers of IL-4R. This difference could reflect specific requirements for their protective performance in the neonatal intestine.

Animals↗

PubMed1992

Interferon-gamma stimulates lipid metabolism in human monocytes.

In nonactivated human monocytes, radiolabeled oleic, arachidonic, and palmitic acids are primarily incorporated into neutral lipids and phosphatidylcholine. Each of these fatty acids is also incorporated into phosphatidylethanolamine, phosphatidylserine, phosphatidylinositol, and sphingomyelin in characteristic proportions which do not differ between donors. The phospholipid head group precursors, choline and serine, are incorporated into phosphatidylcholine, and phosphatidylserine and serine is incorporated into phosphatidylethanolamine and sphingomyelin. The incorporation of these lipid precursors and the total lipid content of monocytes activated with interferon-gamma were compared to those of nonactivated monocytes. Fatty acid incorporation into interferon-gamma-activated monocytes was dramatically increased, particularly for palmitic acid. Palmitic acid incorporation into phosphatidylcholine, phosphatidylethanolamine, phosphatidylserine, phosphatidylinositol, and sphingomyelin was increased in activated cells by 167-387% at 2 hr and 215-274% at 4 hr compared to that of controls. The greatest increase in incorporation was for palmitic acid into sphingomyelin. Incorporation of arachidonic acid into phosphatidylinositol and serine into phosphatidylethanolamine was also increased in the interferon-gamma-activated monocytes. The total lipid content of activated and nonactivated monocytes did not differ. These results suggest that IFN-gamma activation induces a short-term stimulation of phospholipid metabolism which does not alter the gross lipid composition. Such modifications of phospholipid metabolism may be important in signal transduction as well as an indication of functional changes in the membranes of activated macrophages.

Fatty Acids↗

PubMed1991

Survival of human macrophages infected with Mycobacterium avium intracellulare correlates with increased production of tumor necrosis factor-alpha and IL-6.

The long term survival of peripheral blood derived human macrophages (M phi) from normal, healthy donors after infection with Mycobacterium avium intracellulare (MAI) correlates with the increased induction of TNF-alpha and IL-6 mRNA and protein by the infected M phi. This conclusion is based on the following observations: M phi from approximately 30% of the blood donors in our study die 3 to 4 days after inoculation (MAI-growth nonsupportive (NS], whereas M phi from the other donors survive inoculation with MAI for 7-10 days (MAI-growth supportive (S)). S-type M phi when infected with MAI had markedly increased amounts of TNF-alpha and IL-6 mRNA and protein when compared to NS-type M phi. The effect of LPS on the induction of TNF-alpha mRNA and protein was also significantly enhanced in S-type M phi in comparison to NS cells. In contrast, IL-1 beta mRNA and protein production had similar increases in both donor types when infected with MAI or stimulated with LPS. The phenotype of the donors in the amount of TNF-alpha and IL-6 produced in response to MAI infection remained stable for a period of more than 1 yr. Pretreatment of NS M phi with recombinant human granulocyte-macrophage-CSF, but not IFN-gamma, however, converted NS M phi into a S-type cell phenotype. These granulocyte-macrophage-CSF pretreated NS M phi survived infection with MAI for a longer period of time and also had increased production of both TNF-alpha and IL-6 mRNA and protein. Cultures of S-type M phi infected with MAI had higher numbers of intracellular bacteria when compared to cultures of NS-infected M phi. Thus, increased survival of MAI-infected human M phi in vitro is correlated to increased production of TNF-alpha and IL-6 in response to infection with MAI.

Adult↗

PubMed1991

Increased proteolytic activity on the surface of monocytes from patients with rheumatoid arthritis.

Studies on the expression and localization of the urokinase receptor on peripheral blood monocytes of patients with rheumatoid arthritis (RA), patients with osteoarthritis, and healthy volunteers showed a significant increase in the total number of urokinase receptors on monocytes of patients with RA, compared with osteoarthritis patients or with healthy subjects. The increase in the total number of urokinase receptors in RA was due to an elevation in the number of endogenously occupied urokinase receptors. These data provide evidence that increased proteolytic activity might contribute to the pronounced degradation of cartilage and connective tissue in patients with RA.

Adult↗

PubMed1991

The HIV core protein p24 inhibits interferon-gamma-induced increase of HLA-DR and cytochrome b heavy chain mRNA levels in the human monocyte-like cell line THP1.

Cells from the human monocytic cell-line THP1 were incubated prior to activation with IFN-gamma or LPS with varying amounts of p24, the main product of the HIV gag gene and the major component of the virus core. The IFN-gamma-dependent increase of mRNA for HLA-DR and for the heavy chain of cytochrome b was markedly decreased by p24 but not by gp120. This effect was abrogated by anti-p24 antibodies. On the other hand, preincubation of THP1 cells with p24 did not affect the accumulation of the LPS-dependent mRNA for TNF alpha and IL1-beta. These results indicate that p24 at concentrations similar to those found in the serum of HIV-infected individuals specifically affects IFN-gamma-induced activation markers.

Blotting, Northern↗

PubMed1991

Interleukin-6 expression in primary macrophages infected with human immunodeficiency virus-1 (HIV-1).

We have investigated the effects of human immunodeficiency virus type-1 (HIV-1) infection on constitutive and lipopolysaccharide (LPS)-induced expression of interleukin-6 (IL-6) in cultured blood monocyte-derived macrophages. Highly productive and cytopathic infection of macrophages was established with the macrophage-tropic HIV-1 BaL strain. On Days 14-28 post infection, infected and mock-infected cells were activated with LPS or control medium for 6-24 hours before harvesting culture supernatants and cellular RNA. IL-6 bioactivity in culture supernatants was measured with the IL-6-dependent B9 cell line. IL-6 mRNA levels were quantitated by Northern blot analysis with scanning densitometry. In the absence of LPS activation, IL-6 activity was near or below the limit of detection in supernatants from both infected and uninfected cultures. Similarly, without LPS stimulation, IL-6 mRNA was not detectable in either infected or uninfected macrophages. After activation with LPS, marked increases in IL-6 mRNA levels and supernatant bioactivity were evident in both infected and uninfected cultures, but the response to LPS was consistently greater in infected macrophages. LPS-induced IL-6 mRNA levels and supernatant bioactivity were 7.4- and 4.4-fold higher, respectively, in infected compared with uninfected macrophages (n = 5, p less than .05). These studies demonstrate that highly productive HIV-1 infection does not increase constitutive IL-6 expression in macrophages, but does prime macrophages for an augmented IL-6 response to LPS. These findings may help define the mechanisms responsible for increased IL-6 production in patients with HIV-1 infection.

Cells, Cultured↗

PubMed1991

Freshly isolated and cultured human monocytes obtained by plasmapheresis kill schistosomula of Schistosoma mansoni.

The efficacy of human peripheral blood monocytes (PBM) in killing of schistosomula is controversial. The purpose of this study was to determine the schistosomulacidal activity of human monocytes isolated by two different techniques. Peripheral blood monocytes were obtained either by venipuncture (PBMv) or plasmapheresis (PBMp), purified on Ficoll-Paque, and cultured briefly. The cells then were incubated with schistosomula (cell parasite ratio of 10(4):1) for 16 to 18 hours with or without interferon-gamma IFN-gamma (600 U/ml) or sera from patients with schistosomiasis as a source of antischistosomal antibodies (HASA). Freshly isolated PBMv treated with IFN-gamma or HASA did not kill schistosomula. Freshly isolated PBMp alone killed 22 +/- 13% (mean +/- standard deviation [SD]; n = 9) of worms over background and after incubation with IFN-gamma and HASA, 30 +/- 17%. PBMp cultured in vitro for 7 days killed 50 +/- 15% (mean +/- SD; n = 12) of the schistosomula. Pretreatment of the cells with IFN-gamma and incubation with HASA did not significantly enhance the parasite killing beyond this level. Electron microscopy showed that freshly isolated PBMp attached to the worms and fused occasionally with the outer tegumental membrane. Granules constituted 1.4% of the cytoplasmic volume. Degranulation onto the parasite surface was not observed. Peripheral blood monocytes obtained by plasmapheresis accumulated glycogen during in vitro culture with the parasite and released threefold more H2O2 than PBMv after exposure to phorbol myristate acetate. Thus plasmapheresis increases the schistosomulacidal activity of PBM, enhances the generation of H2O2 and promotes the accumulation of glycogen.

Animals↗

PubMed1990

A soluble factor produced by inoculation of human monocytes with Leishmania donovani promastigotes suppresses IFN-gamma-dependent monocyte activation.

Whereas human cultured monocytes preactivated with IFN-gamma increase their antileishmanial capacity, monocytes inoculated with Leishmania donovani before IFN-gamma treatment fail to respond with an increase of antileishmanial capacity. Cell surface expression of class II MHC products also fails to be increased by IFN-gamma in the infected monocytes, although the accumulation of HLA-DR alpha-chain mRNA is increased to the same extent in infected and noninfected activated monocytes. This inhibition of monocyte activation is caused in a dose-dependent manner by a soluble substance elaborated into the cell supernatant after inoculation of monocytes with L. donovani and is referred to as activation suppressing factor (ASF). ASF activity can be abrogated by dialysis and by treatment with a proteinase, indicating that ASF is a small peptide.

Animals↗

PubMed1990

Matrix-bound plasminogen activator inhibitor type 1 inhibits the invasion of human monocytes into interstitial tissue.

Invasion of tissue by monocytes in the course of cellular immune reactions is a multistep process that is thought to be based on the action of urokinase type plasminogen activator (u-PA), an ubiquitous serine protease able to convert the zymogen plasminogen into the active protease plasmin. Expression and occupation of urokinase-type plasminogen activator receptors (u-PA-R) are known to be up-regulated by IFN-gamma and TNF-alpha, and endogenously occupied u-PA-R were found to be instrumental in monocyte invasiveness. We used the amnion invasion assay to investigate whether monocyte invasiveness is affected by matrix-bound plasminogen activator inhibitors (PAI) and by fluid phase u-PA. We show in this study that preincubation of amnion membranes with 1.5 U/cm2 PAI-1 decreases invasion of IFN-gamma activated monocytes by 70% compared with controls. Anti-vitronectin antibodies, which block PAI-1 binding to the matrix, abrogate the inhibitory effect of PAI-1 on monocyte invasiveness, indicating that active PAI-1 is bound via matrix-associated vitronectin. In contrast, preincubation of the amnion membrane with PAI-2 which does not bind to the extracellular matrix has no effect on monocyte invasiveness. Finally, the inhibitory action of matrix-bound PAI-1 can be abrogated by addition of 5 IU/ml u-PA to the monocytes in the invasion chamber. These findings indicate that monocyte invasiveness might be regulated not only by expression and occupation of u-PA-R but also by matrix-bound PAI-1.

Amnion↗

PubMed1989

IL-4 inhibits H2O2 production and antileishmanial capacity of human cultured monocytes mediated by IFN-gamma.

The effect of IL-4 on the IFN-gamma-induced state of activation of cultured human monocytes was investigated with regard to their ability to produce hydrogen peroxide and their antileishmanial capacity towards the intracellular parasite Leishmania donovani. IL-4 was found to inhibit the IFN-gamma-dependent hydrogen peroxide production of monocytes. Treatment of monocytes with IFN-gamma (200 to 600 U/ml) for 48 h increased the hydrogen peroxide production fourfold above background. Coincubation of the monocytes with IL-4 (1 to 1000 U/ml) and IFN-gamma (200 to 600 U/ml) inhibited this increase by 50 to 100%. IL-4 alone did not modulate the hydrogen peroxide production of monocytes. Pretreatment of monocytes with IL-4 for 20 min to 3 h was already effective in preventing the IFN-gamma response. Addition of IL-4 not later than 6 h after the start of incubation with IFN-gamma was necessary for an optimal inhibitory effect. IL-4 also inhibited the IFN-gamma-induced antileishmanial capacity of monocytes: IFN-gamma (1000 U/ml) induced a 54 +/- 10% reduction in the number of parasites. Monocytes treated with combinations of IL-4 (100 to 1000 U/ml) and IFN-gamma (1000 U/ml) were unable to reduce the parasite numbers. IL-4 alone did not alter the uptake of Leishmania donovani nor induce antileishmanial activity. These results demonstrate that IL-4 disables human cultured monocytes to respond to IFN-gamma activation.

Animals↗

PubMed1989

Endogenous receptor-bound urokinase mediates tissue invasion of human monocytes.

Macrophages have a marked capacity to invade tissue in the course of cellular immune reactions that is thought to be based on the action of urokinase (u-PA). u-PA is an ubiquitous serine protease that converts the zymogen plasminogen into the active protease plasmin. u-PA binds to specific receptors on the macrophage thereby enabling the cell to degrade interstitial tissue in the microenvironment. Two cytokines produced in the course of cellular immune reactions, IFN-gamma and TNF-alpha, increase the number of u-PA receptors on human cultured monocytes from 14,000 to 64,000 and 30,000 receptors/cell, respectively. We used an amnion invasion assay to investigate whether activated human monocytes exhibit an enhanced capacity to invade interstitial tissue in correlation to the increased numbers of u-PA receptors. We show in this study that IFN-gamma, which increases the number of endogenously occupied and saturable u-PA receptors, causes a threefold increase of monocyte invasion into amnion tissue in comparison to control cells. The anti-u-PA mAb MPW5UK, which blocks the activity of u-PA, inhibits monocyte invasiveness significantly. In contrast, TNF-alpha, which increases only the number of saturable u-PA receptors on monocytes, does not enhance their invasiveness. This finding suggests that only endogenously occupied u-PA receptors are instrumental in monocyte invasiveness. This conclusion is further supported by the findings that: 1) saturation of monocytes with u-PA does not further increase their invasiveness and that 2) plasminogen-activator inhibitor-2, a specific inhibitor of u-PA associated with endogenously occupied, but not of u-PA bound to saturable receptors, inhibits monocyte invasiveness completely.

Amnion↗

PubMed1989

A monoclonal antibody to sialophorin (CD43) induces homotypic adhesion and activation of human monocytes.

Treatment of human monocytes for 24-48 h with the anti-CD43 mAb L10 caused five- to sevenfold stimulation of hydrogen peroxide-producing capacity, an established characteristic of activated monocytes. Peroxide-producing capacity induced by L10 antibody (1.6 +/- 0.3 nmol H2O2/micrograms DNA/h) was comparable with that induced by IFN-gamma (1.3 +/- 0.4 nmol H2O2/micrograms DNA/h), but appeared more rapidly (maximal at 24 h) than in the IFN-gamma-treated monocytes (maximal at 48 h). Treatment of monocytes with L10 mAb also caused dramatic increase in aggregation (homotypic adhesion). Induction of monocyte aggregation by L10 mAb required incubation for 1-8 h in the presence of Mg2+ and was abrogated by TA-1, an anti-LFA-1-alpha mAb. Thus, L10-induced monocyte activation proceeds via a Mg2+-requiring aggregation stage involving LFA-1. Whereas the extent of monocyte aggregation induced by L10 mAb and by IFN-gamma were comparable, the L10-induced aggregation occurred more rapidly (maximal at 8 h) than the IFN-gamma-induced aggregation (maximal at 24 h). The more rapid appearance of aggregation and increased hydrogen peroxide capacity in L10-treated monocytes suggests that the L10-induced activation pathway is independent of IFN-gamma-and IFN-gamma-R dependent events. These findings suggest that the surface molecule CD43 is the receptor of an independent activation pathway that leads in lymphocytes to proliferation and in monocytes to activation.

Antibodies, Monoclonal↗

PubMed1989

Peptides encoded by the calcitonin gene inhibit macrophage function.

Neuropeptides are considered to play an important role in the modulation of a number of immune functions. Calcitonin gene-related peptide (CGRP), one of the neuropeptides, was found to profoundly inhibit the ability of macrophages to produce H2O2 in response to IFN-gamma or to act as APC. For the inhibition of H2O2 production to occur, preincubation of the macrophages with CGRP was required. Among neuropeptides that are similar in size, calcitonin also prevented macrophage activation but adrenocorticotropic hormone did not. These findings suggest that CGRP and calcitonin play an important role in modulating the ability of macrophages to present Ag and to respond to activating factors.

Adrenocorticotropic Hormone↗

PubMed1989

Molecular cloning of a cDNA encoding a human macrophage migration inhibitory factor.

A cDNA encoding a human macrophage migration inhibitory factor (MIF) was isolated, through functional expression cloning in COS-1 cells, from a cDNA library prepared from a lectin-stimulated T-cell hybridoma, T-CEMB. The 115-amino acid polypeptide encoded by the MIF cDNA (p7-1) was effectively released from the transfected COS-1 cells and yielded readily detectable MIF activity in the culture supernatant despite the apparent lack of a classical protein secretory sequence. Insertional mutational analysis and elution of MIF activity from polyacrylamide gel slices demonstrated that the Mr 12,000 protein with MIF activity released by the COS-1 cells is encoded by p7-1. The p7-1 cDNA hybridized with a 700-base mRNA expressed by Con-A-stimulated lymphocytes but not unstimulated lymphocytes. The availability of the MIF cDNA clone and recombinant MIF will facilitate the analysis of the role of this lymphokine in cell-mediated immunity, immunoregulation, and inflammation.

Amino Acid Sequence↗

PubMed1989

Functional characteristics of receptor-bound urokinase on human monocytes: catalytic efficiency and susceptibility to inactivation by plasminogen activator inhibitors.

We compared urokinase-type plasminogen activator (u-PA) in fluid phase and u-PA bound with its receptor on human blood monocytes with respect to proteolytic activity and susceptibility to inactivation by the plasminogen activator inhibitors PAI-1 and PAI-2. Receptor-bound u-PA is catalytically twice as efficient as fluid-phase u-PA. Fluid-phase u-PA is susceptible to rapid inhibition by PAI-1 and PAI-2 at an estimated PAI:u-PA molar ratio of 2:1. In contrast, u-PA bound to endogenously occupied receptors is inhibited by PAI-2 only at PAI:u-PA molar ratios of 20:1, but is not inhibited by PAI-1, u-PA/PAI-1 and u-PA/PAI-2 complexes bind to the receptor with a tenfold lower affinity than u-PA itself. Thus, competition of u-PA/PAI complexes with fluid-phase u-PA for binding to the receptor is unlikely to affect the overall plasminogen activator activity of the monocyte. These findings demonstrate that the activity of receptor-bound u-PA can be modulated by PAI-2, but not by PAI-1, to adjust the cell's proteolytic activity to different local situations.

Catalysis↗

PubMed1988

IFN-gamma, tumor necrosis factor-alpha, and urokinase regulate the expression of urokinase receptors on human monocytes.

The ability of macrophages to reach inflammatory loci is crucial in the function of cellular immunity. Invasive properties of macrophages may be due to the proteinase urokinase which binds to cell surface receptors, and thereby confers on macrophages the capacity for localized proteolysis of the interstitium. Here, we investigated the role of the macrophage-activating factors IFN-gamma, TNF-alpha, and granulocyte-macrophage-CSF and of urokinase on the expression of urokinase receptors by human cultured monocytes. IFN-gamma and TNF-alpha induced increased urokinase binding to human cultured monocytes in a time- and dose-dependent fashion. At optimal concentrations, IFN-gamma (200 U/ml) increased the number of receptors/cell from 14,000 to 64,000, TNF-alpha (50 U/ml) to 30,000, and combinations of IFN-gamma and TNF-alpha to 90,000. Granulocyte-macrophage-CSF had no effect. The enhanced urokinase binding is due to increased numbers of urokinase receptors and not an increased affinity of the receptor for urokinase. In the presence of urokinase during monocyte activation, IFN-gamma induced only 25,000 receptors/cell. However, urokinase does not inhibit increased receptor expression when the cells are activated with TNF-alpha. The effect of urokinase on induction of urokinase receptors by combinations of IFN-gamma and TNF-alpha varied with the dosage of TNF-alpha: A combination of IFN-gamma (200 U/ml) and TNF-alpha (15 U/ml) induced 38,000 receptors/cell in the presence and 90,000 receptors/cells in the absence of urokinase, whereas IFN-gamma (200 U/ml) and TNF-alpha (20 U/ml) induced 90,000 receptors/cell in the absence and presence of urokinase. These studies demonstrate that IFN-gamma, TNF-alpha, and urokinase collectively regulate the number of urokinase receptors on human monocytes. The induction of urokinase receptors may be responsible for increased invasiveness of the activated macrophage.

Binding, Competitive↗