Transcription from the stromelysin promoter is induced by interleukin-1 and repressed by dexamethasone

Exploring S100A8/A9, neopterin, and MMP3 in familial Mediterranean fever

Familial Mediterranean fever (FMF) is characterized by inflammatory attacks due to overactivation of pyrin inflammasome. This study aimed to investigate the reliability of S100A8/A9, neopterin, and matrix metalloproteinase 3 (MMP3) at monitoring subclinical inflammation and disease activity, and at differentiating FMF attacks from appendicitis, the most common misdiagnosis among FMF patients. Blood samples (n = 75), comprising from FMF patients during an attack (n = 20), the same FMF patients during the attack-free period (n = 14), patients with appendicitis (n = 24), and healthy volunteers (n = 17) were obtained. Duplicate determinations of S100A8/A9, neopterin, and MMP-3 levels were conducted using the enzyme-linked immunosorbent assay (ELISA). FMF patients with and without attack and patients with appendicitis had significantly elevated S100A8/A9 levels compared to healthy volunteers (P-values: < 0.001, 0.036, 0.002, respectively). Patients with appendicitis and FMF patients with and without attack had significantly increased serum neopterin levels compared to healthy volunteers (P-value: < 0.001). MMP3 levels were significantly higher among patients with appendicitis and FMF patients during attack compared to healthy controls (P-values: < 0.001, 0.001). Serum levels of S100A8/A9, neopterin, and MMP3 were increased significantly during attacks compared to attack-free periods among FMF patients (P-values: 0.03, 0.047, 0.007). S100A8/A9 emerges as a valuable marker for monitoring disease activity. Neopterin and S100A8/A9 might help physicians to monitor subclinical inflammation during the attack-free periods of FMF patients. MMP3 might aid in diagnosing FMF attacks when distinguishing between attack and attack-free periods is challenging.

Horizontal alignment of 5' -> 3' intergene distance segment tropy with respect to the gene as the conserved basis for DNA transcription

AIM

To study the conserved basis for gene expression in comparative cell types at opposite ends of the cell pressuromodulation spectrum, the lymphatic endothelial cell and the blood microvascular capillary endothelial cell.

METHODS

The mechanism for gene expression is studied in terms of the 5' -> 3' direction paired point tropy quotients (prpT_Qs) and the final 5' -> 3' direction episodic sub-episode block sums split-integrated weighted average-averaged gene overexpression tropy quotient (esebssiwaagoT_Q).

RESULTS

The final 5' -> 3' esebssiwaagoT_Q classifies an lymphatic endothelial cell overexpressed gene as a supra-pressuromodulated gene (esebssiwaagoT_Q ≥ 0.25 < 0.75) every time and classifies a blood microvascular capillary endothelial cell overexpressed gene every time as an infra-pressuromodulated gene (esebssiwaagoT_Q < 0.25) (100% sensitivity; 100% specificity).

CONCLUSION

Horizontal alignment of 5' -> 3' intergene distance segment tropy wrt the gene is the basis for DNA transcription in the pressuromodulated state.

The expression and regulation of matrix metalloproteinase-3 is critically modulated by Porphyromonas gingivalis lipopolysaccharide with heterogeneous lipid A structures in human gingival fibroblasts

Background

Porphyromonas gingivalis lipopolysaccharide (LPS) is a crucial virulence factor strongly associated with chronic periodontitis which is the primary cause of tooth loss in adults. It exhibits remarkable heterogeneity containing tetra-(LPS_1435/1449) and penta-(LPS₁₆₉₀) acylated lipid A structures. Human gingival fibroblasts (HGFs) as the main resident cells of human gingiva play a key role in regulating matrix metalloproteinases (MMPs) and contribute to periodontal homeostasis. This study investigated the expression and regulation of MMPs1-3 and tissue inhibitors of MMP-1 (TIMP-1) in HGFs in response to P. gingivalis LPS_1435/1449 and LPS₁₆₉₀ and hexa-acylated E. coli LPS as a reference. The expression of MMPs 1–3 and TIMP-1 was evaluated by real-time PCR and ELISA.

Results

The MMP-3 mRNA and protein were highly upregulated in P. gingivalis LPS₁₆₉₀- and E. coli LPS-treated cells, whereas no induction was observed in P. gingivalis LPS_1435/1449-treated cells. On the contrary, the expression of MMP-1 and −2 was not significantly affected by P. gingivalis LPS lipid A heterogeneity. The TIMP-1 mRNA was upregulated in P. gingivalis LPS_1435/1449- and E. coli LPS-treated cells. Next, signal transduction pathways involved in P. gingivalis LPS-induced expression of MMP-3 were examined by blocking assays. Blockage of p38 MAPK and ERK significantly inhibited P. gingivalis LPS₁₆₉₀-induced MMP-3 expression in HGFs.

Conclusion

The present findings suggest that the heterogeneous lipid A structures of P. gingivalis LPS differentially modulate the expression of MMP-3 in HGFs, which may play a role in periodontal pathogenesis.

Effects of curcumin and Ginkgo biloba on matrix metalloproteinases gene expression and other biomarkers of inflammatory bowel disease

Treatment of inflammatory bowel disease (IBD) by synthetic active ingredients leads to many side effects. The objective of this study was to manage IBD using natural products as curcumin and Ginkgo biloba. Rats were divided into four groups (control, IBD, curcumin treated, and ginkgo treated). Inflammation was assessed by determination of myeloperoxidase, matrix metalloproteinases, metalloproteinase-1 inhibitor, nitric oxide, hydroxyproline, tumor necrosis factor-alpha, ceruloplasmin, and histopathological scoring. IBD induction significantly increased all measured parameters. Treated groups had significantly lower levels when compared with the IBD group. In conclusion, curcumin and ginkgo were effective in prevention and treatment of IBD.

Variation of matrix metalloproteinase 1 and 3 haplotypes and their serum levels in patients with rheumatoid arthritis and osteoarthritis

The matrix metalloproteinases 1 and 3 (MMP1 and MMP3) are thought to be important in destructive joint changes seen in rheumatoid arthritis (RA) and osteoarthritis (OA) diseases. The aim of this study was to analyze whether functional polymorphisms in the promoter region of the MMP1 and MMP3 genes were associated with RA and OA. The MMP1 (-1607 1G/2G) and MMP3 (-1171 5A/6A) polymorphisms were screened by polymerase chain reaction-restriction fragment length polymorphism in 100 patients with (RA), 100 patients with (OA), and 100 controls. Serum MMP1 and MMP3 levels were measured by enzyme-linked immunosorbent assay. The results reported a significant difference between patients with OA and controls regarding allele distributions of MMP1 polymorphism, but not between patients with RA and controls. For MMP3 polymorphism, the 6A/6A genotype was significantly more frequent in patients with RA and OA than in controls. The haplotype 2G-6A, which carries the abnormal alleles, showed higher frequencies in the patients with RA and OA than in controls (28%, 30% and 8%, respectively). There were no significant differences in serum MMP1 and MMP3 levels between all studied groups. In conclusion, the MMP1 and MMP3 haplotypes may represent genetic determinants for RA and OA in the Egyptian population. The results suggest that MMP polymorphism genotypes may be more useful in predicting joint damage than measurement of serum concentrations of MMP1 and MMP3. Moreover, MMP1 and MMP3 polymorphisms may predict the activity and severity of these diseases.

LIGHT up-regulated on B lymphocytes and monocytes in rheumatoid arthritis mediates cellular adhesion and metalloproteinase production by synoviocytes

OBJECTIVE

To study the expression of LIGHT (tumor necrosis factor superfamily 14) and herpesvirus entry mediator (HVEM; tumor necrosis factor receptor superfamily 14) in rheumatoid arthritis (RA) and to determine the regulatory role of LIGHT on the effector functions of fibroblast-like synoviocytes (FLS).

METHODS

The expression of LIGHT and HVEM was assessed by immunohistochemical staining of synovial tissue and by flow cytometric analysis of mononuclear cells. The presence of HVEM and lymphotoxin beta receptor was measured by reverse transcriptase-polymerase chain reaction and by flow cytometry. The regulation of effector molecules, including matrix metalloproteinases (MMPs) and adhesion molecules, was evaluated. The adhesiveness of FLS was determined by adhesion assay.

RESULTS

HVEM was detected in most cell types within rheumatoid synovial tissue, while only a few cells were positive for LIGHT. In RA patients, LIGHT expression was significantly up-regulated only in CD20+ B cells and monocytes, whereas the mean fluorescence intensity of HVEM was down-regulated in mononuclear cells. The stimulation of FLS with LIGHT resulted in the production of MMPs and the expression of adhesion molecules, which were efficiently inhibited by dexamethasone. LIGHT-mediated up-regulation of MMPs and intercellular adhesion molecule 1 was blocked by inhibitors of NF-kappaB and JNK, whereas up-regulation of vascular cell adhesion molecule 1 was blocked by inhibitors of phosphatidylinositol 3-kinase, as well as NF-kappaB.

CONCLUSION

These data suggest that binding of LIGHT with its receptors may play a role in the progression of inflammation within rheumatoid synovium, especially by mediating the interactions between infiltrating inflammatory cells and stromal cells. These findings thus emphasize the relevance of LIGHT as a potential therapeutic target in RA.

Differential glucocorticoid effects on proliferation and invasion of human trophoblast cell lines

Several clinical situations require continuous glucocorticoid (GC) treatment during pregnancy. A well-known deleterious side effect of such treatment is the higher incidence of growth-restricted fetuses, for which a too shallow trophoblast invasion is presently hypothesised as the underlying cause. This study investigated whether the synthetic GC triamcinolone acetonide (TA) influences proliferation, invasion and endocrine activity of human trophoblast. BeWo and JEG-3 choriocarcinoma cell lines both express GC receptors (western blotting) and were used as models for human trophoblast. JAR devoid cells of GC receptor were used as negative control. The cells were cultured for 48 h without (control) or with 0.5, 5 and 50 microM TA. In the presence and absence of serum, proliferation was determined by cell counting and measuring the cell cycle regulating protein cyclin B1 (Western blotting); invasion was determined by a conventional Matrigel invasion assay and by measuring the secretion (ELISA) of matrix-metalloproteinases (MMP-2, MMP-9) into the culture medium; endocrine activity was assessed by measuring the levels of human chorionic gonadotropin (ELISA) into the culture medium. TA altered the number of viable and dead cells as well as cyclin B1 levels and, to a lesser extent, invasion of BeWo and JEG-3, with a strong influence of serum. BeWo and JEG-3 cells reacted differently and in most instances reverse. In the cell lines used as models of human trophoblast, TA alter some functions relevant to proliferation and invasion, and suggest that caution should be exercised when treating women with GCs during pregnancy.

Glucocorticoid therapy-induced skin atrophy

Glucocorticoids (GCs) are highly effective for the topical treatment of inflammatory skin diseases. Their long-term use, however, is often accompanied by severe and partially irreversible adverse effects, with atrophy being the most prominent limitation. Progress in the understanding of GC-mediated molecular action as well as some advances in technologies to determine the atrophogenic potential of compounds has been made recently. It is likely that the detailed mechanisms of GC-induced skin atrophy will be discovered and in vitro models for the reliable prediction of atrophy will be established in the foreseeable future. This knowledge will not only facilitate safety profiling of established drugs but will also foster further drug discovery by improving compound characterization processes. New insights into GC modes of action will guide optimization strategies aiming at novel GC receptor ligands with improved effect/side effect profile.

Changes in biochemical parameters after anterior cruciate ligament injury

We studied the biochemical characteristics of human knees with deficient anterior cruciate ligaments (ACL) and analysed their relationship to the time after ligamentous injury. Thirty-two patients with isolated ACL-injured knees and six healthy volunteers were enrolled. Synovial fluid samples were centrifuged after aspiration during arthroscopic examination, and aliquots of supernatant were frozen and stored at -80 degrees C. The samples were analysed for interleukin (IL)-1beta, tumour necrosis factor (TNF)-alpha, IL-6, matrix metalloproteinase (MMP)-3, and tissue inhibitor of metalloproteinase (TIMP)-1 using commercially available sandwich enzyme-linked immunosorbent assay. In fluid from ACL-injured knees, the average concentrations of IL-6, MMP-3 and TIMP-1 were highly elevated in comparison with normal controls. There was a statistically significant correlation between the concentrations of MMP-3 and IL-6. The IL-6 and TIMP-1 concentrations were interrelated. The concentration of MMP-3 remained high, independent of the duration since the injury, whereas the TIMP-1 and IL-6 levels decreased. The results suggest that the timing of the treatment of an ACL-injured knee might be of importance.

Isolation, purification and characterization of collagenase from hepatopancreas of the land snail Achatina fulica

Collagenase (matrix metalloproteinase-1, EC:3.4.24.7) was isolated from the hepatopancreas of Achatina fulica and characterized for its enzymatic activity and immunological properties. Procollagenase was isolated using ammonium sulphate precipitation and gel filtration, followed by purification by reverse-phase high performance liquid chromatography in the presence of trifluoroacetic acid and by dialysis in neutral buffer. In the presence of SDS and beta-mercaptoethanol, the procollagenase resolved into two subunits with molecular masses of 63 and 28 kDa, respectively. The 63 kDa fragment retained its ability to bind and degrade gelatin, but the 28 kDa was inactive. Analysis by 2D gel electrophoresis revealed that the 63 kDa fragment was basic (pIs 7.6, 7.8 and 8.15), while the 28 kDa fragment was acidic (pI 4.7 and 5.1). Western blot analysis confirmed the identity of collagenase, as only matrix metalloproteinase-1 rabbit antibodies against human matrix metalloproteinase-1 (N-terminal region) recognized both the isolated procollagenase and the 63 kDa fragment.

A role for matrix metalloproteinases in the pathology and attenuation of Theileria annulata infections

Upon infection with Theileria annulata, bovine leukocytes are induced to express eight novel metalloproteinase activities. In this article, Rachel Adamson and Roger Hall suggest that these enzymes are virulence factors and their presence may explain some of the features of the pathology of the disease. Specifically, they discuss the possibility that the metastatic properties of infected cells, the 'cigarette burn' ulcers and the cachexia characteristic of tropical theileriosis are associated with metalloproteinase expression. Furthermore, they propose that loss of metalloproteinase activity during the generation of a vaccine line could explain the attenuated phenotype.

Effects of interleukin-1beta and dexamethasone on the expression of matrix metalloprotease mRNA by trabecular cells exposed to elevated hydrostatic pressure

PURPOSE

We investigated the effects of interleukin-1beta (Il-1beta) and dexamethasone (Dex) on the expression of matrix metalloprotease-1, -2, -3 and -14 (membrane type-1 MMP-MT1-MMP) as well as tissue inhibitors of matrix metalloproteases (TIMP-1 and -2) mRNA by trabecular cells exposed not only to normal, but also to elevated levels of hydrostatic pressure.

METHODS

Confluent primary cultures of porcine trabecular cells were incubated in a serum-free medium (SFM) as controls, or in SFM containing either 10 ng/ml Il-1beta or 10 nm Dex and exposed to pressures of 15 mmHg or 50 mmHg (corresponding to normal and high intraocular pressure, respectively) in specially designed pressure chambers. After 72 hours, total RNA was extracted from the harvested cells, reverse transcribed and amplified using primers specific to MMP-1, -2, -3 and -14, and TIMP-1 and -2.

RESULTS

The most significant changes were detected in the levels of MMP-3 mRNA in control cells (2.4-fold increase), of TIMP-1 and -2 mRNA in cells treated with Il-1beta (2.6-fold increase) and of MMP-3 mRNA in cells treated with Dex (3.5-fold increase) exposed to 50 mmHg pressure.

CONCLUSION

Because MMP-3 (stromelysin) mRNA showed the highest upregulation, our findings suggest that trabecular cells preferentially degrade and turn over the proteoglycan components of the extracellular matrix in response to short-term exposure to increased hydrostatic pressure with and without Dex as a homeostatic mechanism.

Stromelysin 1 (matrix metalloproteinase 3) and HLA-DRB1 gene polymorphisms: Association with severity and progression of rheumatoid arthritis in a prospective study

OBJECTIVE

To test the hypothesis of an association between a polymorphism in the matrix metalloproteinase 3 (MMP-3) gene promoter and the susceptibility, severity, and progression of rheumatoid arthritis (RA), and to further document the association between HLA-DRB1 alleles encoding the shared epitope (SE) and the severity and progression of RA.

METHODS

Patients with early RA (n = 103) were included in this prospective study. A total radiographic damage score (TDS; by the Sharp/van der Heijde method) was used to quantify RA severity at baseline and after 4 years of followup. The 5A/6A biallelic polymorphism in the MMP-3 gene promoter was analyzed using fluorescence-based polymerase chain reaction (PCR). HLA-DRB1 genotyping was performed using PCR methods. Control subjects (n = 127) were unrelated healthy individuals.

RESULTS

MMP-3 allele carriage rates and allele and genotype frequencies did not differ between patients and controls. The MMP-3 6A/6A genotype was associated with the highest TDS both at baseline and after a 4-year followup and with the highest progression of the TDS over the 4 years of followup. The DRB1 SE+/+ genotype was associated with the highest TDS after a 4-year followup and with the highest progression of the TDS over the 4 years of followup. Patients homozygous for MMP-3 6A and DRB1 SE had the highest progression of the TDS.

CONCLUSION

This study provides the first evidence of an association between a polymorphism in the MMP-3 gene promoter and the severity and progression of RA, but not RA susceptibility. Investigation of this polymorphism could be combined with that of DRB1 gene polymorphism to improve the predictive accuracy and management strategy in early RA.

Cyclooxygenase 2-dependent prostaglandin E2 modulates cartilage proteoglycan degradation in human osteoarthritis explants

OBJECTIVE

To examine cyclooxygenase-2 (COX-2) enzyme expression, its regulation by interleukin-1 beta (IL-1 beta), and the role of prostaglandin E(2) (PGE(2)) in proteoglycan degradation in human osteoarthritic (OA) cartilage.

METHODS

Samples of human OA articular cartilage, meniscus, synovial membrane, and osteophytic fibrocartilage were obtained at knee arthroplasty and cultured ex vivo with or without IL-1 beta and COX inhibitors. COX expression was evaluated by immunohistochemistry and Western blot analysis. The enzymatic activity of COX was measured by conversion of arachidonic acid to PGE(2). Cartilage degradation was evaluated by measuring the accumulation of sulfated glycosaminoglycans in the medium.

RESULTS

IL-1 beta induced robust expression of COX-2 and PGE(2) in OA meniscus, synovial membrane, and osteophytic fibrocartilage explants, whereas low levels were produced in OA articular cartilage. IL-1 beta also induced cartilage proteoglycan degradation in OA synovial membrane-cartilage cocultures. Increased proteoglycan degradation corresponded to the induction of COX-2 protein expression in, and PGE(2) production from, the synovial membrane. Dexamethasone, neutralizing IL-1 beta antibody, or the selective COX-2 inhibitor, SC-236, attenuated both the IL-1 beta-induced PGE(2) production and cartilage proteoglycan degradation in these cocultures. The addition of PGE(2) reversed the inhibition of proteoglycan degradation caused by SC-236.

CONCLUSION

IL-1 beta-induced production of COX-2 protein and PGE(2) was low in OA articular cartilage compared with that in the other OA tissues examined. IL-1 beta-mediated degradation of cartilage proteoglycans in OA synovial membrane-cartilage cocultures was blocked by the selective COX-2 inhibitor, SC-236, and the effect of SC-236 was reversed by the addition of exogenous PGE(2). Our data suggest that induction of synovial COX-2-produced PGE(2) is one mechanism by which IL-1 beta modulates cartilage proteoglycan degradation in OA.

Paracrine regulation of matrix metalloproteinase expression in endometriosis

Following retrograde menstruation, shed endometrial tissue fragments attach to and invade the peritoneal surface to form established endometriotic lesions. With disease progression, the biochemically active lesions undergo remodeling and become fibrotic. Matrix metalloproteinase enzymes (MMPs) and the tissue inhibitors of metalloproteinases (TIMPs) play a significant role in normal endometrial remodeling during menses. Anomalous expression of MMPs and TIMPs has been identified in endometriotic lesions as compared to their highly regulated expression in eutopic endometrium. The paracrine mechanisms regulating misexpression of MMPs and TIMPs by endometriotic lesions are, however, not well defined. Misexpression of the MMPs and TIMPs may be due to innate anomalies in the eutopic endometrium from women with endometriosis, in the resident immune cells and peritoneal cells that juxtapose the ectopic endometrium, and/or numerous substances present in peritoneal fluid of women with endometriosis. The majority of MMPs are under strict transcriptional regulation. Steroid hormones and cytokines appear to act on the MMP promoter, either independently or in consort, to provide both positive and negative regulation of these genes. Misregulated expression of MMPs and TIMPs is associated with a more aggressive phenotype and a cascade of events facilitating peritoneal extracellular matrix degradation and establishment or remodeling of endometriotic lesions. The mechanisms by which MMP and TIMP expression are misregulated warrant further investigation as such information may provide insight into novel therapeutic modalities for endometriosis.

Myocardial remodelling and matrix metalloproteinases in heart failure: turmoil within the interstitium

The progression of left ventricular (LV) dysfunction is often accompanied by changes in LV geometry and myocardial architecture that can be defined as LV myocardial remodelling. An important event in LV myocardial remodelling is alterations in the extracellular matrix (ECM). A family of zinc-dependent proteases implicated in facilitating myocardial tissue remodelling by degrading components of the ECM are the matrix metalloproteinases (MMPs). The temporal expression of MMPs and the local tissue inhibitors of MMPs (TIMPs) appear to be differentially regulated in several cardiovascular disease states such as myocardial infarction, LV hypertrophy, and dilated cardiomyopathy. Both pharmacological and genetic modulation of myocardial MMP expression has been demonstrated to alter the course of LV myocardial remodelling and LV dysfunction. The induction of MMPs within the myocardium during the heart failure process probably results in liberation of bioactive molecules, proteolytic degradation of ECM structural proteins, and alterations in cell-cell contact and adhesion. Modifying MMP expression and activation may reduce this turmoil within the myocardial interstitium and, in turn, prove to be a useful therapeutic paradigm for heart failure treatment.

Glucocorticoid-regulated gene expression during cutaneous wound repair

Glucocorticoids exert a deleterious effect on the wound healing process, which has been suggested to result from the anti-inflammatory action of these steroids. In addition, recent studies have demonstrated that glucocorticoids regulate the expression of various genes at the wound site which are likely to encode key players in the wound repair process. Using a murine full-thickness excisional wound healing model, we analyzed the effect of dexamethasone on the expression of various cytokines, growth factors, enzymes, and extracellular matrix molecules in normal and wounded skin. We demonstrate that the proinflammatory cytokines interleukin-1 alpha and -beta, tumor necrosis factor alpha, keratinocyte growth factor, transforming growth factors beta 1, beta 2, and beta 3 and their receptors, platelet-derived growth factors and their receptors, tenascin-C, stromelysin-2, macrophage metalloelastase, and enzymes involved in the generation of nitric oxide are targets of glucocorticoid action in wounded skin. These results indicate that anti-inflammatory steroids inhibit wound repair at least in part by influencing the expression of these key regulatory molecules.

Macrophage migration inhibitory factor up-regulates expression of matrix metalloproteinases in synovial fibroblasts of rheumatoid arthritis

Neutral matrix metalloproteinases (MMPs) are responsible for the pathological features of rheumatoid arthritis (RA) such as degradation of cartilage. We herein show the up-regulation of MMP-1 (interstitial collagenase) and MMP-3 (stromelysin) mRNAs of cultured synovial fibroblasts retrieved from rheumatoid arthritis (RA) patients in response to macrophage migration inhibitory factor (MIF). The elevation of MMP-1 and MMP-3 mRNA was dose-dependent and started at 6 h post-stimulation by MIF, reached the maximum level at 24 h, and was sustained at least up to 36 h. Interleukin (IL)-1beta mRNA was also up-regulated by MIF. These events were preceded by up-regulation of c-jun and c-fos mRNA. Tissue inhibitor of metalloproteinase (TIMP)-1, a common inhibitor of these proteases, was slightly up-regulated by MIF. Similarly, mRNA up-regulation of MMP-1 and MMP-3 was observed in the synovial fibroblasts of patients with osteoarthritis. However, their expression levels were much lower than those of RA synovial fibroblasts. The mRNA up-regulation by MIF was inhibited by the tyrosine kinase inhibitors genestein and herbimycin A, as well as the protein kinase C inhibitors staurosporine and H-7. On the other hand, the inhibition was not seen after the addition of the cyclic AMP-dependent kinase inhibitor, H-8. The mRNA up-regulation of MMPs was also inhibited by curcumin, an inhibitor of transcription factor AP-1, whereas interleukin-1 receptor antagonist, an IL-1 receptor antagonist, failed to inhibit the mRNA up-regulation. Considering these results, it is suggested that 1) MIF plays an important role in the tissue destruction of rheumatoid joints via induction of the proteinases, and 2) MIF up-regulates MMP-1 and MMP-3 via tyrosine kinase-, protein kinase C-, and AP-1- dependent pathways, bypassing IL-1beta signal transduction.

Effect of thalidomide, octreotide, and prednisolone on the migration and proliferation of RPE cells in vitro

PURPOSE

The retinal pigment epithelium (RPE) is involved in the pathogenesis of age-related macular degeneration. The purpose of this study was to assess the effect of thalidomide, octreotide, and prednisolone on the proliferation and migration of bovine RPE cells in vitro.

METHODS

The migration assay was performed in double-chamber-wells separated by a membrane filter with 8 microm pores. Cells were allowed to migrate vertically for 7 hr, afterwards the cells on both filtersides were fixed, stained, and the migrated cells were counted. To examine RPE proliferation, bovine RPE cells were seeded subconfluently followed by an incubation with octreotide, thalidomide or prednisolone in a concentration gradient for 24 hr. Stimulation or inhibition of DNA synthesis was measured by [(3)H]-thymidine incorporation. Statistical analysis was performed with the paired student's t-test.

RESULTS

Statistically significant (p < 0.05) inhibition of RPE cell proliferation was measured for thalidomide at a concentration of 10-50 microg/ml, for octreotide at a concentration of 5 x 10(-4) and 5 x 10(-5) M, and for prednisolone at a concentration of 250 and 500 microg/ml as compared to the negative control. RPE cell migration was significantly (p < 0.05) inhibited by thalidomide at a concentration of 10 microg/ml, by octreotide at a concentration of 5 x 10(-5) M, and also by prednisolone at a concentration of 500 microg/ml as compared to the negative control.

CONCLUSIONS

Although the main effect of thalidomide, octreotide, and prednisolone when treating patients with choroidal neovascular membranes is probably related to the inhibition of angiogenesis it should be kept in mind that these substances may additionally inhibit RPE proliferation and migration.

Identification of a novel dexamethasone-sensitive RNA-destabilizing region on rat monocyte chemoattractant protein 1 mRNA

Glucocorticoids are potent anti-inflammatory agents widely used in the treatment of human disease. We have previously shown that the inflammatory cytokine monocyte chemoattractant protein 1 (MCP-1) is regulated posttranscriptionally by glucocorticoids in arterial smooth muscle cells (SMC). To elucidate the mechanism mediating this effect, in vitro-transcribed radiolabeled MCP-1 mRNA was incubated with cytoplasmic extracts from SMC and analyzed by gel electrophoresis. Extracts from SMC treated with platelet-derived growth factor (PDGF) did not degrade the transcripts for up to 3 h. In contrast, extracts from cells treated with 1 microM dexamethasone (Dex) alone or in combination with PDGF degraded the probe with a half-life of approximately 15 min. Dex had maximal effect at concentrations above 0.01 microM and was effective on both rat and human MCP-1 transcripts. By deletion analysis, the Dex-sensitive region of the MCP-1 mRNA was localized to the initial 224 nucleotides (nt) at the 5' end and did not involve an AU-rich sequence in the 3' untranslated end. The 224-nt region conferred Dex sensitivity to heterologous mRNA. These studies provide new insights into the molecular mechanisms underlying the effect of glucocorticoids on gene expression.

p300/cAMP-responsive element-binding protein interactions with ets-1 and ets-2 in the transcriptional activation of the human stromelysin promoter

In this paper we show that transcription factors Ets-1 and Ets-2 recruit transcription adapter proteins p300 and CBP (cAMP-responsive element-binding protein) during the transcriptional activation of the human stromelysin promoter, which contains palindromic Ets-binding sites. Ets-2 and p300/CBP exist as a complex in vivo. Two regions of p300/CBP between amino acids (a.a.) 328 and 596 and a. a. 1678 and 2370 independently can interact with Ets-1 and Ets-2 in vitro and in vivo. Both these regions of p300/CBP bind to the transactivation domain of Ets-2, whereas the C-terminal region binds only to the DNA binding domain of Ets-2. The N- and the C-terminal regions of CBP (a.a. 1-1097 and 1678-2442, respectively) which lack histone acetylation activity independently are capable of coactivating Ets-2. Other Ets family transcription factors failed to cooperate with p300/CBP in stimulating the stromelysin promoter. The LXXLL sequence, reported to be important in receptor-coactivator interactions, does not appear to play a role in the interaction of Ets-2 with p300/CBP. Previous studies have shown that the stimulation of transcriptional activation activity of Ets-2 requires phosphorylation of threonine 72 by the Ras/mitogen-activated protein kinase signaling pathway. We show that mutation of this site does not affect its capacity to bind to and to cooperate with p300/CBP.

Effect of Steroid Hormones and Retinoids on the Formation of Capillary-Like Tubular Structures of Human Microvascular Endothelial Cells in Fibrin Matrices Is Related to Urokinase Expression

Angiogenesis, the formation of new capillary blood vessels, is a feature of a variety of pathological processes. To study the effects of a specific group of hormones (all ligands of the steroid/retinoid/thyroid hormone receptor superfamily) on the angiogenic process in humans, we have used a model system in which human microvascular endothelial cells from foreskin (hMVEC) are cultured on top of a human fibrin matrix in the presence of basic fibroblast growth factor and tumor necrosis factor-α. This model mimics the in vivo situation where fibrin appears to be a common component of the matrix present at sites of chronic inflammation and tumor stroma. Our results show that testosterone and dexamethasone are strong inhibitors and all-trans retinoic acid (at-RA) and 9-cis retinoic acid (9-cis RA) are potent stimulators of the formation of capillary-like tubular structures. These effects are mediated by their respective nuclear hormone receptors as demonstrated by the use of specific synthetic receptor agonists and antagonists. 17β-estradiol, progesterone, and 1,25-dihydroxyvitamin D3 did not affect or only weakly affected in vitro angiogenesis, which may be related to the lack of significant nuclear receptor expression. Although hMVEC express both thyroid hormone receptors α and β, no effect of thyroid hormone on tube formation was found. The effects of testosterone, dexamethasone,at-RA, and 9-cis RA on tube formation were accompanied by parallel changes in urokinase-type plasminogen activator (u-PA) expression, at both mRNA and antigen levels. Exogenous suppletion of the medium with single chain u-PA enhances tube formation in our in vitro model, whereas quenching of u-PA activity (but not of tissue-type plasminogen activator activity) or of u-PA binding to u-PA receptor by specific antibodies suppressed basal and retinoid-stimulated tube formation. Moreover, addition of scu-PA to testosterone- or dexamethasone-treated hMVEC restored the suppressed angiogenic activity for a substantial part. Aprotinin, an inhibitor of plasmin activity, completely inhibited tube formation, indicating that the proteolytic properties of the u-PA/u-PA receptor complex are crucial in this process. Our results show that steroid hormones (testosterone and dexamethasone) and retinoids have strong, but opposite effects on tube formation in a human in vitro model reflecting pathological angiogenesis in the presence of fibrin and inflammatory mediators. These effects can be explained by hormone-receptor–mediated changes in u-PA expression, resulting in enhanced local proteolytic capacity of the u-PA/u-PA receptor complex.

© 1998 by The American Society of Hematology.

Effect of Steroid Hormones and Retinoids on the Formation of Capillary-Like Tubular Structures of Human Microvascular Endothelial Cells in Fibrin Matrices Is Related to Urokinase Expression

Angiogenesis, the formation of new capillary blood vessels, is a feature of a variety of pathological processes. To study the effects of a specific group of hormones (all ligands of the steroid/retinoid/thyroid hormone receptor superfamily) on the angiogenic process in humans, we have used a model system in which human microvascular endothelial cells from foreskin (hMVEC) are cultured on top of a human fibrin matrix in the presence of basic fibroblast growth factor and tumor necrosis factor-α. This model mimics the in vivo situation where fibrin appears to be a common component of the matrix present at sites of chronic inflammation and tumor stroma. Our results show that testosterone and dexamethasone are strong inhibitors and all-trans retinoic acid (at-RA) and 9-cis retinoic acid (9-cis RA) are potent stimulators of the formation of capillary-like tubular structures. These effects are mediated by their respective nuclear hormone receptors as demonstrated by the use of specific synthetic receptor agonists and antagonists. 17β-estradiol, progesterone, and 1,25-dihydroxyvitamin D3 did not affect or only weakly affected in vitro angiogenesis, which may be related to the lack of significant nuclear receptor expression. Although hMVEC express both thyroid hormone receptors α and β, no effect of thyroid hormone on tube formation was found. The effects of testosterone, dexamethasone,at-RA, and 9-cis RA on tube formation were accompanied by parallel changes in urokinase-type plasminogen activator (u-PA) expression, at both mRNA and antigen levels. Exogenous suppletion of the medium with single chain u-PA enhances tube formation in our in vitro model, whereas quenching of u-PA activity (but not of tissue-type plasminogen activator activity) or of u-PA binding to u-PA receptor by specific antibodies suppressed basal and retinoid-stimulated tube formation. Moreover, addition of scu-PA to testosterone- or dexamethasone-treated hMVEC restored the suppressed angiogenic activity for a substantial part. Aprotinin, an inhibitor of plasmin activity, completely inhibited tube formation, indicating that the proteolytic properties of the u-PA/u-PA receptor complex are crucial in this process. Our results show that steroid hormones (testosterone and dexamethasone) and retinoids have strong, but opposite effects on tube formation in a human in vitro model reflecting pathological angiogenesis in the presence of fibrin and inflammatory mediators. These effects can be explained by hormone-receptor–mediated changes in u-PA expression, resulting in enhanced local proteolytic capacity of the u-PA/u-PA receptor complex.

© 1998 by The American Society of Hematology.

Dimethylheptyl-THC-11 oic acid: a nonpsychoactive antiinflammatory agent with a cannabinoid template structure

OBJECTIVE

To assess the antiinflammatory activity of dimethylheptyl-THC-11 oic acid (DMH-11C), a nonpsychoactive synthetic derivative of tetrahydrocannabinol.

METHODS

Acute inflammation was induced by injection of interleukin-1beta and tumor necrosis factor alpha into subcutaneous air pouches formed on the backs of mice. Inflammation was quantified 6 hours later by pouch fluid leukocyte counts. Adjuvant-induced polyarthritis in rats was used as a model of chronic inflammation and joint tissue injury. Animals were either untreated, treated with safflower oil, or treated with DMH-11C in safflower oil. Arthritis was assessed by clinical observation and by histomorphologic evaluation of tibiotarsal joints.

RESULTS

Oral administration of DMH-11C reduced the accumulation of pouch fluid leukocytes and significantly reduced the severity of adjuvant-induced polyarthritis. Histopathologic studies of tibiotarsal joints showed that DMH-11C treatment attenuated pannus formation and joint tissue injury.

CONCLUSION

DMH-11C suppresses acute inflammation in the subcutaneous air pouch in mice and chronic joint inflammation characteristic of adjuvant disease in rats. These results demonstrate the potential use of this nonpsychoactive cannabinoid as an antiinflammatory agent.

Beta 2-microglobulin induces stromelysin production by human synovial fibroblasts

beta 2-Microglobulin (beta 2-m) is a major constituent of amyloid fibrils in hemodialysis-associated amyloidosis (HAA), a serious complication in patients on long-term hemodialysis. The most distinctive pathological feature of HAA is the deposition of amyloid fibrils with subsequent articular inflammation and destruction. However, the pathological role of beta 2-m is not well known at present. We investigated the effects of beta 2-m on the production of proteinases from synovial fibroblasts isolated from patients with rheumatoid arthritis. beta 2-m stimulated synovial fibroblasts to produce stromelysin, a neutral matrix metalloproteinase (MMP-3). The production of MMP-2 and of a tissue inhibitor of metalloproteinase-1 (TIMP-1) were not enhanced by beta 2-m-treated synovial fibroblasts. Stromelysin is capable of degrading several components of the extracellular matrix and believed to be the key enzyme causing articular destruction in inflammatory joint diseases. Our results suggest a novel role for beta 2-m in articular inflammation and destruction mediated by stromelysin in HAA.

Differential regulations of matrix metalloproteinases and tissue inhibitors of metalloproteinases in dermal fibroblasts by dibutyril cyclic AMP

The influence of dibutyril cyclic AMP (dbcAMP) on the gene expression of matrix metalloproteinases (MMP)-1, MMP-2, MMP-3, tissue inhibitors of metalloproteinases (TIMP)-1 and TIMP-2 was investigated in human skin fibroblasts by northern analyses. The treatment of dbcAMP increased MMP-1 and MMP-3 mRNA levels but decreased TIMP-1 mRNA levels in time and dose dependent manners. Procollagen alpha 1 (I), MMP-2 and TIMP-2 mRNA levels were unaltered by this reagent. Our data indicate that dbcAMP potentially enhances the degradation of extracellular components of connective tissue.

Identification of promoter activity and differential expression of transcripts encoding the murine stromelysin-1 gene in renal cells

Stromelysin-1, matrix metalloproteinase-3 (MMP-3), is an important endopeptidase selectively expressed by somatic cells in organ tissues. The renal tubulointerstitium, for example, comprises tubular epithelium and interstitial fibroblasts forming the principal mass of the kidney. We observed that mRNA encoding stromelysin-1 is detectable in murine renal fibroblasts, but not in proximal tubular epithelium. Transcripts measured by RNase protection assay in renal fibroblasts increase following exposure to phorbol ester, and thereafter, activated stromelysin-1 protein can be detected in culture media by Western blotting. A 6.4 Kb genomic clone containing the putative stromelysin-1 promoter was isolated and a relevant 2.1 Kb PstI restriction fragment including 2.1 Kb of the immediate 5'-flanking region was sequenced on both strands. Two transcriptional start sites were identified by primer extension; the major start site corresponded to a previously established position in the rat promoter, and a second undescribed minor transcriptional start site was located 16 bp upstream of the primary site. A HiNF-A chromatin-activating element at -106 bp was found in the early promoter region of pR336 and an active AP-1 site at -72 bp with an Ets/PEA-3 motif at -203 bp was suggested by transient transfection of luciferase minigenes into renal fibroblasts responsive to phorbol ester. This Ets element was identical to a site in the early promoter of the fibroblast-specific gene FSP1. A baseline enhancement in activity of pR336 in fibroblasts was further observed with the addition of 5' flanking sequence out to -1980 bp. This additional region of flanking sequence contains two modular regions: one of multiple PEA-3 elements between -684 bp and -1955 bp and a second region between -1929 bp and -1980 bps containing a second AP-1 site at -1929 bp, a MBF-1/ MEP-1 metal binding site, and a PPAR peroxisome proliferator element at -1950 bp. Our findings implicate a gene structure with expected activity in a mesenchymal phenotype. The PKC-dependent regulation of the stromelysin-1 gene supports the notion that it may be modulated during inflammation or tissue remodeling.

Interleukin-1beta secreted from monocytic cells induces the expression of matrilysin in the prostatic cell line LNCaP

Matrilysin is a matrix metalloprotease that is overexpressed in cancer cells of epithelial origin and in normal tissues during events involving matrix remodeling such as the cycling endometrium. We previously observed that inflamed ductule and acinar epithelia in the prostate also overexpress matrilysin. The presence of infiltrating macrophages in these areas prompted us to determine if factors secreted from monocytes could induce matrilysin expression in a human prostatic cell line. Conditioned media collected from the monocyte cell line THP-1 following lipopolysaccharide treatment substantially induced matrilysin protein and mRNA expression in LNCaP prostate carcinoma cells. Matrilysin expression in LNCaP cells was also induced by recombinant interleukin (IL)-1 (50 pM), but not by equimolar concentrations of recombinant tumor necrosis factor-alpha or IL-6. The matrilysin-inducing activity of THP-1 conditioned medium was completely abrogated by preincubation with a neutralizing antibody to IL-1beta. Transient transfection analyses with a chimeric human matrilysin promoter-chloramphenicol acetyltransferase reporter construct demonstrated that IL-1beta activates transcription through the matrilysin promoter in LNCaP cells. This is the first report of matrilysin induction by an inflammatory cytokine in a cell line of epithelial origin, and the results suggest a potential mechanism for the overexpression of matrilysin in inflamed ducts and glands of the prostate.

Cloning and developmental expression of a membrane-type matrix metalloproteinase from chicken

We have cloned a novel matrix metalloproteinase (MMP) from cultured chicken embryo fibroblasts. The cDNA-derived protein sequence contains 608 amino acids including a C-terminal hydrophobic transmembrane domain of 24 amino acids and a cytoplasmic domain of 20 amino acids. This chicken MMP is 72% similar to a recently described membrane-type MMP (MT-MMP) from human placenta (Sato, H., Takino, T., Okada, Y., Cao, J., Shinagawa, A., Yamamoto, E., and Seiki, M. (1994) Nature 370, 61-65). Accordingly, we name this novel MMP chicken MT-MMP. As shown by Northern blotting, two MT-MMP mRNAs of 6 and 10 kilobases are constitutively expressed but only modestly regulated by growth factors and cytokines in cultured chicken embryo fibroblasts. Both mRNAs are abundant in the head and body of 8- and 9-day-old chicken embryos. As shown by in situ mRNA hybridization, MT-MMP is expressed in embryonic neural tube, spinal ganglia, and respiratory epithelium, as well as in developing cartilage and muscle. Using reverse transcription-polymerase chain reaction, we have found MT-MMP mRNA in 2-day-old chicken embryos and extraembryonic membranes. In addition, a strong correlation was observed between the mRNA expression of MT-MMP and 72-kDa type IV collagenase. Collectively, the early MT-MMP mRNA expression and its co-localization in several tissues with 72-kDa type IV collagenase mRNA suggest that the MT-MMP plays an important role in early development.

Androgen receptor-Ets protein interaction is a novel mechanism for steroid hormone-mediated down-modulation of matrix metalloproteinase expression

Matrix metalloproteinases belong to a family of structurally related enzymes that plays important role in tissue morphogenesis, differentiation, and wound healing. Their expression is negatively regulated by several members of the steroid hormone receptor family. This is thought to occur through interaction of the steroid receptors with the transcription factor AP-1 that is otherwise required for positive regulation. Here, we demonstrate that AP-1 is not always a target for down-regulation of expression of matrix metalloproteinases by steroid receptors. Androgen receptor negatively regulates matrix metalloproteinase-1 expression not through AP-1 but through a family of Ets-related transcription factors that are also required for positive regulation. This negative regulation is specific for the androgen receptor. It does not require the DNA binding activity but needs amino-terminal sequences of the receptor. These results identify a novel regulatory pathway for negative regulation utilized by a member of the steroid hormone receptor family for down-regulating the expression of matrix metalloproteinases.

Increased mRNA expression of metalloproteinase-9 in peripheral blood monocytes from patients with immunoglobulin A nephropathy

We examined metalloproteinase (MMP)-1, -2, -3, and -9 mRNA expression by peripheral blood monocytes from 50 patients with immunoglobulin A (IgA) nephropathy, 20 with membranous nephropathy, 10 with minimal-change nephrotic syndrome, five with focal glomerulosclerosis, 30 with non-IgA proliferative glomerulonephritis, and 40 healthy normal controls who were comparable with regard to age and sex. Monocytes from patients with IgA nephropathy expressed a higher level of MMP-9 mRNA than those from patients with other forms of glomerulonephritis or from healthy controls (MMP-9 to glyceraldehyde-3-phosphate dehydrogenase ratio: IgA nephropathy, 1.68 +/- 0.24; membranous nephropathy, 0.22 +/- 0.08; minimal-change nephrotic syndrome, 0.24 +/- 0.06; focal glomerulosclerosis, 0.32 +/- 0.08; non-IgA proliferative glomerulonephritis, 0.30 +/- 0.12; and healthy controls, 0.16 +/- 0.04). When the biopsy specimens were classified into four grades according to the severity of glomerular and interstitial pathology, highly significant differences were observed among MMP-9 mRNA levels in monocytes from all four groups of patients with IgA nephropathy (grade I, 0.44 +/- 0.09; grade II, 1.06 +/- 0.26; grade III, 2.22 +/- 0.68; grade IV, 2.86 +/- 0.88). In addition, MMP-9 mRNA levels from patients with IgA nephropathy correlated with urinary protein excretion (P < 0.001). However, we detected minimal mRNA expression of MMP-1, -2, and -3 by peripheral blood monocytes from patients with IgA nephropathy or other forms of glomerulonephritis and from normal healthy controls. Our results suggest that increased MMP-9 mRNA expression in circulating monocytes may contribute to the progression of IgA nephropathy.

Progression of coronary atherosclerosis is associated with a common genetic variant of the human stromelysin-1 promoter which results in reduced gene expression

There is a common polymorphism in the promoter sequence of the human stromelysin-1 gene, with one allele having a run of six adenosines (6A) and the other five adenosines (5A). We have previously reported, in a 3-year follow-up study of patients with coronary atherosclerosis, that those patients who are homozygous for the 6A allele show a more rapid progression of the disease. In this study, we have investigated whether the 5A/6A promoter polymorphism plays a role in the regulation of stromelysin-1 gene expression. In transient transfection experiments, a stromelysin-1 promoter construct with 6A at the polymorphic site was found to express less of the chloramphenicol acetyltransferase reporter gene than a construct containing 5A. Electrophoretic mobility shift assay and DNase I footprinting revealed the interaction of one or more nuclear protein(s) with the DNA sequence at the 5A/6A polymorphic site. The binding of one of the nucleoprotein factors was more readily detectable with an oligonucleotide probe corresponding to the 6A allele as compared with a probe corresponding to the 5A allele. Replacing the core binding sequence with a random DNA sequence abolished the interaction between the nuclear protein(s) and the probe and also increased reporter gene expression in transiently transfected cells. Thus, the common 5A/6A polymorphism of the human stromelysin-1 promoter appears to play an important role in regulating stromelysin-1 gene expression and may be involved in the progression of coronary heart disease.

Transcriptional downregulation of stromelysin by tetracycline

We investigated the role of tetracycline in the transcriptional regulation of matrix metalloproteinases. Using interleukin-1beta (IL-1) induced stromelysin as a model system, we describe the repression of the endogenous stromelysin RNA accumulation, as well as the transcriptional inhibition of various stromelysin promoter/chloramphenicol-acetyltransferase constructs in transient transfection assays. The inhibition occurred in a dose-dependent fashion, with an IC50 of about 1 microM. Our results suggest that the transcriptional inhibition by tetracycline is not due to a block of activity of the activating protein complex 1 (AP-1) but is mediated by sequences upstream of the AP-1 binding site.

Protein kinase C isotypes required for phorbol-ester induction of stromelysin-1 in rat fibroblasts

The phorbol-ester tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) is a potent inducer of the metalloproteinase stromelysin in fibroblasts in vivo and in several cultured cell lines. Rat-1 and Rat-2 fibroblasts, however, do not respond to TPA stimulation by induction of stromelysin gene activity, although collagenase promoter-mediated activity is induced threefold by TPA treatment in these cells. We determined that rat fibroblasts expressed protein kinase C(PKC)alpha, PKCdelta, PKCepsilon, and PKCzeta but neither the mRNA nor the protein for PKCbeta. When Rat-2 fibroblasts were stably transfected with an expression vector producing PKCbeta, however, TPA treatment of these variants resulted in a 3.1-fold induction of stromelysin promoter-mediated luciferase activity compared with a 1.3-fold induction in parental Rat-2 cells (P<0.002). Transient transfection of PKCepsilon produced a small but significant increase in TPA-stimulation of both stromelysin- and collagenase-mediated gene expression. These results suggest that there are PKC isotype-specific signaling pathways that can differentially regulate matrix metalloproteinase gene expression.

Structure and promoter characterization of the human stromelysin-3 gene

In the present study, we have isolated the human stromelysin-3 (ST3) gene which encodes a matrix metalloproteinase (MMP) expressed in fibroblastic cells of tissues associated with intense remodeling. The gene was found to span 11.5 kilobases (kb) including 8 exons and 7 introns. The genomic organization of ST3 gene exons is well conserved compared to other members of the MMP family, except for the 3 last exons corresponding to the hemopexin-like domain and to a long 3'-untranslated region. The transcription initiation site was located 31 nucleotides downstream of a TATA box. Analysis of 1.4 kb of 5'-flanking DNA sequence in the ST3 gene promoter revealed the presence of putative regulatory elements, but no consensus sequence for AP1-binding site in contrast to other MMP promoters. However, a specific cis-acting retinoic acid responsive element of the DR1 type was identified in the proximal region (-385) of the ST3 gene promoter. Transient transfection experiments demonstrated that a minimal promotor activity could be modulated by various sequences within the 3.4 kb of 5'-flanking region, and that the ST3 promoter was transactivated by retinoic acid receptors in the presence of retinoic acid. These findings indicate that the human ST3 gene promoter is characterized by structural and functional features which differ from those previously described in other MMP promoters, and further supports the possibility that ST3 gene expression is controlled by specific factors during tissue remodeling.

Preliminary report: genetic variation in the human stromelysin promoter is associated with progression of coronary atherosclerosis

Stromelysin is a member of the family of metalloproteinases that degrade extracellular matrix. In situ hybridisation and histopathological studies suggest that stromelysin activity may be important in the connective tissue remodelling processes associated with atherogenesis and plaque rupture. Single strand conformation polymorphism analysis identified a common polymorphism in the stromelysin gene promoter located 1171 bp upstream from the start of transcription in which one allele has a run of six adenosines (6A) and another has five adenosines (5A). 72 men with coronary heart disease, were genotyped. They were participants in the St Thomas' Atherosclerosis Regression Study who were randomised to receive usual care (UC), dietary intervention (D), or diet plus cholestyramine (DC), with angiography at baseline and at 39 months. In these patients the frequency of the 5A allele was 0.49 (95% CI from 0.41 to 0.57) and was not significantly different from that in a sample of 354 healthy UK men. In the UC group, patients who were homozygous for the 6A allele showed greater progression of angiographic disease than those with other genotypes: the minimum absolute width of coronary segments decreased by 0.04 (SEM 0.10) mm for 5A5A, 0.20 (0.07) mm for 5A6A, and 0.67 (0.19) mm for 6A6A (P < 0.01). The findings were similar but slightly less significant for the change in mean absolute width of coronary segments (P < 0.05). No significant associations were seen in patients in the D or DC groups. In data pooled from the three treatment groups, the 6A6A genotype was significantly associated with greater progression of coronary atherosclerosis than other genotypes in patients with baseline percentage diameter stenosis less than 20% (P < 0.05), but not in those with baseline percentage diameter stenosis greater than or equal to 20%. These results provide the first evidence of a link between genetic variation in stromelysin and progression of coronary atherosclerosis and support the hypothesis that connective tissue remodeling mediated by metalloproteinases contribute to the pathogenesis of atherosclerosis.

Inhibition of interleukin 1-induced biosynthesis of stromelysin by the calcium antagonist TMB-8 (8-(N, N-diethylamino)octyl-3,4,5-trimethoxybenzoate HCl)

This study was done to identify agents that can inhibit interleukin 1 (IL1)-induced stromelysin biosynthesis and to gain insight into the mechanism of IL1 action. For this purpose, various agents known to modulate calcium-dependent signal transduction pathway were evaluated in rabbit synovial fibroblast (RSF) cultures. Only the conditioned medium from RSF treated with the intracellular calcium antagonist TMB-8 (8-(N,N-diethylamino)-octyl 3,4,5-trimethoxybenzoate hydrochloride) had significantly lower proteoglycan-degrading metalloproteinase activity than controls. Biosynthetic labeling, immunoprecipitation and immunohistochemical studies, using a polyclonal antibody against rabbit stromelysin, demonstrated that TMB-8 inhibited synthesis stromelysin, the proteoglycan-degrading matrix metalloproteinase. Further evaluation of the TMB-8 effect revealed that the compound had no effect on secretion and that it was not acting by preventing activation of the proenzyme or by inhibiting the enzyme activity. These results suggest that TMB-8 may be inhibiting stromelysin synthesis by limiting intracellular calcium levels.

The human stromelysin promoter contains a previously unreported 1.0-kb sequence

Cloning and characterization of the promoter region controlling the gene encoding human stromelysin (Str) has been previously reported [Quinones et al., J. Biol. Chem. 264 (1989) 8339-8344]. We have characterized independently isolated genomic clones of the STR promoter, designated pSKStrB and 682, that are considerably different from the published sequence. Although the sequences up to an XbaI site at -480 of the 5' regions are identical, a novel 1.0-kb segment exists upstream from -480. This sequence is absent from the published clone, but its presence in the genomic DNA from twelve individuals has been confirmed by both PCR analysis and restriction mapping. Upstream of the novel 1-kb segment, the sequence of the published clone reappears, but in pSKStrB exists in inverse orientation.

Spinal prodynorphin gene expression in collagen-induced arthritis: influence of the glucocorticosteroid budesonide

Changes in the spinal expression of the opioid precursor and prodynorphin, which has been implicated in the response to peripheral inflammation, were examined with semi-quantitative in situ hybridization histochemistry in rats subjected to collagen II-induced arthritis. The effects of glucocorticosteroid treatment on the basal and inflammation-induced prodynorphin expression were evaluated. Collagen II-induced arthritis caused a 16-fold increase in prodynorphin mRNA levels which comprised all neurons expressing low levels under normal conditions. In the superficial dorsal horn, one group of neurons of a large size reacted with a dramatic increase of prodynorphin mRNA, while another group of small neurons exhibited a moderate elevation of prodynorphin mRNA levels. In the deep dorsal horn of arthritic rats, most prodynorphin neurons were large and showed high prodynorphin mRNA levels. Systemic treatment with the glucocorticosteroid budesonide attenuated the arthritis-induced increase of prodynorphin mRNA expression in a topospecific manner. The budesonide-induced reduction of prodynorphin mRNA levels was more pronounced in the deep dorsal horn than in the superficial dorsal horn. Budesonide treatment of control animals caused a small, but significant increase in prodynorphin mRNA levels in the superficial laminae I/II without affecting prodynorphin mRNA levels in the deep dorsal horn. The degree of arthritis correlated closely with spinal prodynorphin mRNA levels. The tight correlation between severity of arthritis and prodynorphin mRNA levels in non-treated and corticosteroid-treated arthritic rats suggests that spinal prodynorphin expression is a good parameter for the evaluation of the influence of peripheral inflammation and of the efficacy of analgesic/anti-inflammatory drugs in its treatment. Opposite effects of budesonide on basal and inflammation-induced prodynorphin expression may involve a spinal site of action in addition to peripheral anti-inflammatory mechanisms. We suggest that the collagen II-induced arthritis in the rat is an excellent model for human rheumatoid arthritis allowing for the study of molecular plasticity of anti-inflammatory and anti-nociceptive drug action at different levels of the neuroaxis.

Glucocorticoid receptors and resistance to glucocorticoids in hematologic malignancies

Glucocorticoids are highly effective in inducing the cytolysis of cells of lymphocytic origin. This property has resulted in their incorporation into chemotherapy regimens used in the treatment of hematologic malignancies. Studies at the molecular and cellular levels have demonstrated that the hormone-induced cytolytic response is mediated through a highly specific cytoplasmic glucocorticoid receptor (GR). The GR has been cloned and sequenced and found to be organized into a discrete series of domains which mediate the receptor functions of hormone binding, nuclear translocation, DNA binding and transcriptional modulation. Thus, the binding of glucocorticoids by the GR induces a series of cellular events which result in the activation or repression of a network of glucocorticoid responsive genes and produces a specific cellular response. Prolonged exposure to glucocorticoids ultimately causes resistance to develop; thereby limiting the usefulness of this class of drugs. Studies addressing the mechanism of resistance have shown that the GR is the primary target of genetic alterations that lead to resistance to cytolysis. Using mouse and human cell lines as model systems, it has been shown that the vast majority of glucocorticoid resistant mutants express low levels or altered forms of the GR. Similarly, in vivo studies on patients have suggested that low GR levels are associated with a poor response to glucocorticoid based therapies. Recently, aberrant GR isolated from a patient with multiple myeloma resistant to glucocorticoids were found to harbor deletions in their hormone binding domains. Sequencing of the receptors suggested that each arose as a result of alternate splicing events. In both cases, the latter event produces a receptor unable to bind hormone leading to the speculation that alternate splicing may serve as a mechanism by which a cell evades the effects of glucocorticoids. The therapeutic implications for patients expressing aberrant receptors is discussed.

Expression and localization of matrix-degrading metalloproteinases during colorectal tumorigenesis

The metalloproteinase matrilysin is widely expressed in the epithelial tumor cells of malignant colorectal adenocarcinomas. Approximately 50% of benign adenomas also express low levels of matrilysin that is focally localized. The expression of stromelysin-1, stromelysin-3, and gelatinase A was observed in the stromal component of several carcinomas and was not present in adenomatous tissue. The expression of interstitial collagenase and gelatinase B was observed in occasional adenomas and carcinomas. Stromelysin-2 transcripts were not detectable in any of the samples examined. Tissue inhibitor of metalloproteinase-1 gene expression was widespread and was observed in both epithelial and stromal cells of adenomas and carcinomas. These results indicate that matrilysin gene expression is an early event in colorectal tumorigenesis and that the expression of stromelysin-1, stromelysin-3, and gelatinase A is primarily a late event. The observed gene expression patterns suggest that matrilysin may participate in early events in tumor progression and that multiple members of the metalloproteinase family may work in concert to facilitate late-stage tumor invasion and metastasis.

Expression of metalloproteinases in pigmented villonodular synovitis

Pigmented villonodular synovitis (PVNS) is an idiopathic proliferative synovial process composed of two predominant cell types: mononuclear histiocytic cells and giant cells. This lesion can be locally invasive and can result in bone cyst formation and late cartilage and bone loss. Because metalloproteinases have been implicated in the joint destruction occurring in inflammatory arthritis and in the ability of certain tumors to invade adjacent tissues, their presence in PVNS was determined. Synovial tissue samples were collected at surgical synovectomy from the knees of 10 patients with a prior histological diagnosis of PVNS. Pigmented villonodular synovitis synovium was examined for the presence of the metalloproteinases collagenase and stromelysin. Messenger RNA (mRNA) for collagenase and stromelysin was present in all patient samples, although in varying amounts. In situ hybridization studies on synovial tissue sections identified synovial lining cells as the predominant cells expressing these metalloproteinases. Occasional infiltrating mononuclear histiocytic cells also were producing metalloproteinase mRNA. Giant cells did not express mRNA for the metalloproteinases collagenase and stromelysin. These results suggest that collagenase and stromelysin may be among the mediators of cartilage and bone loss that can occur in PVNS.

Mechanistic features associated with induction of metalloproteinases in human gingival fibroblasts by interleukin-1

Human gingival fibroblasts were treated with recombinant interleukin-1 (IL-1) to determine the effect of this stimulus on the relative expression of collagenase (MMP-1), stromelysin (MMP-3) and plasminogen activator (PA) mRNA. The steady-state mRNA levels for these genes were determined on Northern blots. IL-1 induced steady-state levels of these mRNAs to different extents. Nuclear run-on transcription studies showed that IL-1 induction of neutral metalloproteinase may be transcriptionally regulated. Actinomycin D and protein kinase inhibitors decreased the mRNA production for all three metalloproteinases, whereas cycloheximide decreased the production of collagenase and stromelysin mRNA. Protein kinase inhibitors (H7/H8) decreased production of the three mRNAs to different extents. This study demonstrates a potentially important role for IL-1 in the regulation of metalloproteinase expression in human gingival fibroblasts. The ability of IL-1 to induce the expression of stromelysin, collagenase and PA may define a pivotal role for this cytokine in the pathogenesis of periodontitis.