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E F Remmers

Publications and source records attributed to E F Remmers.

At least 73 records · Page 4Linked to original sources
PubMed1991

Platelet-derived growth factors and heparin-binding (fibroblast) growth factors in the synovial tissue pathology of rheumatoid arthritis.

The pathology of rheumatoid arthritis (RA) is characterized by massive tumor like hyperplasia of synovial connective tissues. Fibroblast like cells and microvascular endothelial cells are the predominant cell types present in this invasive tissue, particularly at sites of bone erosions. Identification of growth factors or cytokines that drive this process is an important goal of current research. Here we review evidence that platelet-derived growth factor (PDGF)-like and heparin-binding fibroblast growth factor (HBGF)-like polypeptides play a significant role in this process. For example, messenger RNA transcripts for PDGF-A, PDGF-B, HBGF-1, and HBGF-2 are present in RA synovial tissue specimens, and immunoreactive PDGF-like and HBGF-1- and -2-like polypeptides are present in RA synovia. Levels of expression are significantly higher in RA synovia than in osteoarthritis (OA) synovia, and their expression correlates with the extent and intensity of mononuclear cell infiltration. Similarly, PDGF-receptor expression is elevated in RA synovia compared with OA synovia. High levels of tyrosine phosphorylation and Fos and Myc expression are also characteristic of RA synovia and occur in cells after PDGF- and HBGF-receptor interaction. These and other observations strongly support the view that PDGF-like and HBGF-like factors are involved in stimulating the proliferative and invasive phenotype of RA synovial connective tissue cells.

Animals↗
PubMed1991

Production of platelet derived growth factor B chain (PDGF-B/c-sis) mRNA and immunoreactive PDGF B-like polypeptide by rheumatoid synovium: coexpression with heparin binding acidic fibroblast growth factor-1.

We present evidence supporting the hypothesis that locally produced platelet derived growth factor (PDGF) B-like polypeptides, as well as heparin binding growth factor-1 (HBGF-1), are involved in stimulating the pronounced hyperplasia of rheumatoid synovial stromal fibroblastlike cells. Explanted rheumatoid synovial tissues in vitro spontaneously secreted, in a time dependent manner, mitogenic activity for rheumatoid synoviocytes that was neutralizable by anti-PDGF antibody. PDGF B/c-sis mRNA transcripts were detected in synovium from patients with rheumatoid arthritis (RA) (n = 5). Spontaneous PDGF B-like synthesis was detected by immunoprecipitation of radiolabeled PDGF B-like polypeptides secreted by explanted tissues. Furthermore, rheumatoid synovial tissues, particularly macrophage-like cells, immunostained specifically with anti-PDGF B chain. The extent and intensity of staining and mononuclear cell infiltration were highly correlated. Immunostaining of osteoarthritic and normal synovial tissues was significantly less than RA synovium. PDGF-B immunostaining of synovial specimens previously characterized for expression of HBGF-1, the precursor of acidic fibroblast growth factor (aFGF), revealed that the extent and intensity of expression of HBGF-1 and PDGF-B were highly correlated.

Arthritis, Rheumatoid↗
PubMed1990

IL-1 regulation of transin/stromelysin transcription in rheumatoid synovial fibroblasts appears to involve two antagonistic transduction pathways, an inhibitory, prostaglandin-dependent pathway mediated by cAMP, and a stimulatory, protein kinase C-dependent pathway.

IL-1, like other agents that have been shown a capacity to induce protein kinase C, is a potent transcriptional activator of the metalloproteinase, stromelysin, in synovial and other fibroblasts. cAMP has been shown to inhibit stromelysin transcription in fibroblasts of nonsynovial origin, and is regarded as an important second messenger for IL-1. In addition to stimulating metalloproteinase transcription, IL-1 also induces PGE2 production in synoviocytes. We determined that rIL-1 alpha led to the time-dependent accumulation of intracellular cAMP in serum-starved rheumatoid synovial fibroblasts, and that the effect was blocked by indomethacin. The cAMP agonists forskolin, 3-isobutyl-1-methylxanthine, and PGE2 suppressed the IL-1 induction of stromelysin; conversely, indomethacin superinduced IL-1-elicited stromelysin mRNA. These results were recapitulated on the transcriptional level in cells transfected with the rat transin/stromelysin promoter in a reporter (CAT) construct. 2',5'-Dideoxyadenosine, an inhibitor of adenylate cyclase, also augmented the IL-1 induction of stromeylsin mRNA, as did H-8, a specific inhibitor of the cAMP-dependent protein kinase A. Staurosporine and H-7, inhibitors of protein kinase C, blocked the IL-1 induction of stromelysin mRNA. We conclude that IL-1 appears to stimulate at least two transduction pathways in synovial fibroblasts from patients with rheumatoid arthritis, and that these have antagonistic effects on the regulation of stromelysin transcription.

Adenylyl Cyclase Inhibitors↗
PubMed1990

Cytokines and growth regulation of synoviocytes from patients with rheumatoid arthritis and rats with streptococcal cell wall arthritis.

Paracrine growth factors probably stimulate the pathologic proliferation of synovial fibroblast-like cells (synoviocytes) in rheumatoid arthritis (RA), but the relative importance of various factors is highly controversial. To address this problem, we compared the effects of highly purified or recombinant cytokines, in serum-free medium, on the in vitro long-term growth of synoviocytes from patients with RA and rats with streptococcal cell wall (SCW) arthritis. Of the factors tested (PDGF, aFGF, bFGF, EGF, TGF-beta, IL-1-alpha, TNF-alpha and IFN-gamma), PDGF, was clearly the most potent stimulant of long-term growth of both rat and human synoviocytes. The strong mitogenic activity of rheumatoid synovial fluids was significantly inhibited by neutralizing anti-PDGF antibody, thus confirming the importance of PDGF. EGF, TGF-beta, IL-1-alpha, TNF-alpha, and IFN-gamma had minimal effects. Similar to the effects on anchorage-independent growth, TGF-beta 1 and 2, inhibited serum- or PDGF-stimulated anchorage-dependent growth. Considered in the context of other reports, these data support the view that cytokines such as PDGF, and possibly aFGF and bFGF, play major roles in stimulating synoviocyte hyperplasia in RA and SCW arthritis, whereas TGF-beta may inhibit synoviocyte growth.

Animals↗
PubMed1989

Transforming growth factor-beta production by synovial tissues from rheumatoid patients and streptococcal cell wall arthritic rats. Studies on secretion by synovial fibroblast-like cells and immunohistologic localization.

The growth of synovial fibroblast-like cells from patients with rheumatoid arthritis and rats with streptococcal cell wall (SCW)-induced arthritis in vitro under anchorage-independent conditions is inhibited by transforming growth factor-beta (TGF-beta). Because this growth factor is present in rheumatoid synovial fluids, we studied whether this cytokine might be secreted by cells in rheumatoid synovial tissue. We show that synovial tissues from patients with rheumatoid arthritis and osteoarthritis, and rats with SCW-induced arthritis, contain TGF-beta-1 mRNA. TGF-beta, predominantly type 1, was spontaneously secreted in vitro by synovial tissue explants and synovial fibroblast-like cells. In addition, TGF-beta could be detected immunohistochemically in cells throughout rheumatoid and SCW-induced arthritic rat synovial tissues. Finally, exogenous TGF-beta induced collagen and inhibited collagenase mRNA levels by cultured synoviocytes. These data support an autocrine role for TGF-beta in the regulation of synoviocytes in rheumatoid arthritis and, in light of its demonstrated effects on the immune system, suggest that TGF-beta might also have important paracrine effects on infiltrating inflammatory cells.

Animals↗
PubMed1989

Platelet-derived growth factor and IL-1 interactions in rheumatoid arthritis. Regulation of synoviocyte proliferation, prostaglandin production, and collagenase transcription.

We show that platelet-derived growth factor (PDGF) and IL-1 interact in both a synergistic and antagonistic manner to regulate synovial fibroblast-like cells (synoviocytes) derived from patients with rheumatoid arthritis. PDGF and IL-1 operated synergistically in vitro to stimulate synoviocyte proliferation in the presence of indomethacin. However, when these same cells were treated with PDGF and IL-1 in the absence of indomethacin, IL-1 inhibited PDGF-stimulated synoviocyte proliferation. Moreover, exogenous PGE2, a PG known to be produced in response to IL-1, dramatically inhibited synoviocyte proliferation induced by PDGF. PDGF also acted synergistically to markedly increase production of PGE2 stimulated by IL-1. This is in contrast to the antagonistic effect PDGF had on IL-1-stimulated collagenase transcription. IL-1 stimulated collagenase transcription, but PDGF did not. It in fact inhibited IL-1 stimulation of collagenase gene expression. These data differ somewhat from those reported for dermal fibroblasts. Our data further indicate that the effects of cytokines vary from one cell type to another, even amongst "fibroblasts," and illustrate the complexity of cytokine regulation of rheumatoid synoviocyte function.

Arthritis, Rheumatoid↗
PubMed1989

Anchorage-independent growth of synoviocytes from arthritic and normal joints. Stimulation by exogenous platelet-derived growth factor and inhibition by transforming growth factor-beta and retinoids.

Exuberant tumor-like synovial cell proliferation with invasion of periarticular bone is a feature of rheumatoid arthritis in humans and of streptococcal cell wall (SCW)-induced arthritis in rats. These histologic observations prompted us to examine synoviocytes from arthritic joints for phenotypic characteristics of transformed cells. The capacity to grow in vitro under anchorage-independent conditions is a characteristic that correlates closely with potential in vivo tumorigenicity. In medium supplemented with 20% serum or in basal media supplemented with platelet-derived growth factor (PDGF), early passage synoviocytes from both SCW-induced and rheumatoid arthritic joints formed colonies in soft agarose. Epidermal growth factor (EGF), interleukin 1 (IL-1), tumor necrosis factor-alpha (TNF-alpha), interferon-gamma (IFN-gamma), and transforming growth factor-beta (TGF-beta) did not support growth, although EGF enhanced PDGF-dependent growth. On the other hand, TGF-beta, as well as all-trans-retinoic acid, inhibited colony growth. Early passage normal rat and human synoviocytes also grew under the same conditions, but lung, skin, and late-gestation embryonic fibroblast-like cells did not. Considered in the context of other published data our findings provide cogent evidence that synoviocytes, but not other types of fibroblast-like cells, readily acquire phenotypic characteristics commonly associated with transformed cells. Expression of the transformed phenotype in the inflammatory site is likely regulated by paracrine growth factors, such as PDGF and TGF-beta.

Animals↗
PubMed1989

Transin/stromelysin expression in the synovium of rats with experimental erosive arthritis. In situ localization and kinetics of expression of the transformation-associated metalloproteinase in euthymic and athymic Lewis rats.

Transin is a neutral metalloproteinase initially isolated from malignantly transformed rat fibroblasts and subsequently shown to be homologous to human stromelysin. We performed Northern blot analysis on synovial tissue specimens from Lewis rats with proliferative and invasive streptococcal cell wall (SCW) arthritis. Transin mRNA was present in abundance, as was the mRNA of the c-myc oncogene, which is associated with cellular proliferation. Immunohistochemical staining of synovia from rats with chronic SCW arthritis showed high-level transin expression in the cells of the lining layer and underlying stroma, as well as in chondrocytes and osteoclasts in subchondral bone. Intense nuclear staining for the Myc oncoprotein was also detected with a cross-reactive antibody to v-Myc. Transin stained similarly in the early, rapid-onset, thymus-independent, acute phase of SCW arthritis. In the T cell-dependent adjuvant arthritis, transin expression was noted by day 4, 6 d before the influx of mononuclear cells and the onset of clinical disease. Athymic rats did not express transin. We concluded that transin is a marker of proliferative, invasive arthritis in rats and appears early in the course of disease development, but requires a competent immune system to sustain its expression in these model arthropathies.

Animals↗
PubMed1989

Transin/stromelysin expression in rheumatoid synovium. A transformation-associated metalloproteinase secreted by phenotypically invasive synoviocytes.

Transin is a neutral metalloproteinase whose mRNA was first isolated from rat fibroblasts that had undergone malignant transformation. The protein is highly expressed in malignant rather than benign animal tumors. Its human analog is stromelysin, a 51-kd metalloproteinase initially isolated from cultured human synoviocytes. Northern blot analysis demonstrated that rheumatoid arthritis synovial tissue contained significantly higher levels of stromelysin mRNA than did osteoarthritis synovial tissue. Cultured synoviocytes were also shown to express stromelysin mRNA, and an affinity-purified anti-peptide antiserum to stromelysin specifically immunoprecipitated the stromelysin protein from the conditioned medium of cultured explant rheumatoid synoviocytes. Immunohistochemical staining of rheumatoid synovium demonstrated specific cytoplasmic staining of cells of the synovial lining layer, stromal fibroblasts, and endothelial cells. Osteoarthritic synovia showed significantly less stromelysin staining. Similarly, rheumatoid synovia demonstrated marked nuclear staining for the proliferation- and transformation-associated Myc oncoprotein. In contrast, osteoarthritic synovia showed negligible staining. These results support the belief that the proliferative, invasive behavior of rheumatoid synoviocytes reflects the expression of biochemical features generally associated with phenotypically transformed, malignant tumors. Clearly not a malignancy, the rheumatoid synovium appears to be paracrine driven by mediators generated in local inflammatory milieu.

Arthritis, Rheumatoid↗
PubMed1988

Multiple negative elements upstream of the murine c-myc gene share nuclear factor binding sites with SV40 and polyoma enhancers.

We previously identified a 716 bp DNA segment, 424 to 1140 bp 5' of the murine c-myc gene, which exhibited the properties of a transcriptional 'dehancer' because it negated the effects of the SV40 enhancer (Remmers et al., 1986). Here, we show that this 716 bp 'dehancer region' is composed of multiple negative elements each of which functions at a distance of > 1 Kb to inhibit the SV40 enhancer. One of these negative elements displays lymphoid cell specificity. HeLa cell nuclear factor binding sites are found within these negative effector sequences. One of these binding sites is related to that of the Py EF-C transcription factor which recognizes a short dyad symmetry element within the polyoma enhancer. Interestingly, a dimer of the Py EF-C recognition sequence exhibited a strong 'dehancer effect' in the pSV2CAT expression vector. These negative elements may function by interfering with transcription factors required for SV40 enhancer activity.

Animals↗
PubMed1988

Hyperplastic synoviocytes from rats with streptococcal cell wall-induced arthritis exhibit a transformed phenotype that is thymic-dependent and retinoid inhibitable.

It has been suggested that streptococcal cell wall-induced arthritis in LEW/N rats resembles a localized neoplasm consisting of, in part, a proliferative and invasive population of fibroblast-like synoviocytes. To further pursue this concept, the synoviocytes from diseased rats were characterized in situ and in vitro for various parameters of "transformation." The spindle-shaped synoviocytes were found throughout the synovium and were the predominant cell type at sites of invasion of bone and cartilage by synovium. They stained intensely for vimentin, a microfilament prominently expressed in immature and transformed mesenchymal cells. They stained variably for Ia antigens and did not exhibit T cell surface antigens nor did they stain with histochemical stains characteristic of monocytes or granulocytes. Electron microscopy confirmed their fibroblastlike morphology and suggested high grade metabolic activity. In primary culture, the abnormal synoviocytes were adherent, grew rapidly and did not contact inhibit. Moreover, they grew under anchorage-independent conditions. These abnormal growth characteristics were inhibited by all-trans retinoic acid. Finally, explants of the arthritic synovium formed short-lived tumorlike nodules in athymic nude mice. These observations, considered in the context of other data, support the concept that the pathologic process represents a thymic-dependent, nonmalignant, locally invasive inflammatory neoplasm.

Animals↗
PubMed1986

The first exon of the c-myc proto-oncogene contains a novel positive control element.

We have identified a positive modulator within the c-myc first exon downstream of the gene's transcription initiation sites, P1 and P2. We introduced myc-CAT (chloramphenicol acetyltransferase) hybrid genes into three cell lines (BJAB, COS and HeLa) and measured their expression by either CAT enzymatic activity, S1 nuclease protection or by a nuclear 'run-on' transcription assay. Removal of 46 bp from the 3' end of the first exon results in a decrease of myc-CAT expression and P2 activity. A 438-bp exon 1 segment, lacking the normal myc promoters, efficiently drives the expression of SV40 early promoters. We find that this first exon segment efficiently functions as a positive modulator only in its sense orientation, 3' of a nearby promoter. The positive effects of the myc first exon and the SV40 enhancer are complementary.

Animals↗
PubMed1986

A negative transcriptional control element located upstream of the murine c-myc gene.

We have investigated the nature of regulatory sequences within the vicinity of the murine c-myc locus by analyzing the expression of myc-chloramphenicol acetyl transferase (CAT) vectors transfected into a human lymphoblastoid cell line (BJAB) and a monkey fibroblast line (COS). CAT enzymatic assays and S1 nuclease protection experiments reveal that a negative element resides 428-1188 bp 5' of the first c-myc promoter, P1. This 760-bp segment of 5'-flanking c-myc DNA dramatically inhibits CAT gene expression in the pSV2CAT vector when placed in either orientation approximately 1.7 kb 3' (and approximately 3.2 kb 5' on the circular plasmid) from the SV40 promoter region. By employing this strategy, we were unable to identify an analogous DNA segment that is closer to or within the first c-myc exon. We propose that this 5' c-myc region be termed a 'dehancer' since this negative element has the opposite properties of a transcriptional enhancer.

Animals↗
PubMed1983

c-myc Gene rearrangements involving gamma immunoglobulin heavy chain gene switch regions in murine plasmacytomas.

In murine plasmacytomas, the c-myc gene has frequently been found to undergo rearrangement by virtue of a T(12;15) chromosome translocation. The immunoglobulin heavy chain gene switch region (S alpha) constitutes the target for most of these recombinations particularly in IgA producing plasmacytomas. We sought to identify non-S alpha myc target sites in several IgG producing tumors. The c-myc target in MPC-11 (a BALB/c IgG2b producing plasmacytoma) has been cloned, localized to the Igh-C locus and identified as the gamma 2a heavy chain gene switch region (S gamma 2a). Furthermore, by Southern blot hybridization, we have determined that the S gamma 2b region is the c-myc target in two NZB IgG2b producing plasmacytomas. The potential relation between Ig class expressed and c-myc translocation target is discussed.

Animals↗
PubMed1982

Production and characterization of monoclonal antibodies to cholera toxin.

Monoclonal antibodies against cholera toxin were produced to obtain highly specific antisera to cholera toxin. Fifteen hybridoma cell lines producing monoclonal antibodies specific for the determinants of cholera toxin were derived from the fusion of mouse myeloma cells and spleen cells from mice immunized with cholera toxin. The cell lines were stabilized, examined for specific antibody production, and immortalized by freezing cultured cells and tumor cells which had been grown subcutaneously in mice. All cell lines continued antibody secretion upon thawing. The antibodies produced by the hybridoma cell lines were characterized by determination of the class of light- and heavy-chain components and by determination of specificity for the cholera toxin subunit. All of the antibodies contained the k light chain, 4 contained the mu heavy chain, and the remaining 11 contained the gamma 1 heavy chain. Ten of the monoclonal antibodies are specific for the B subunit of cholera toxin, and three are specific for the A subunit. The remaining two appear to react with both subunits.

Animals↗