Up-regulation of matrix metalloproteinase-1 expression in U937 cells by low-density lipoprotein-containing immune complexes requires the activator protein-1 and the Ets motifs in the distal and the proximal promoter regions

Vascular Age, Metabolic Panel, Cardiovascular Risk and Inflammaging in Patients With Rheumatoid Arthritis Compared With Patients With Osteoarthritis

Introduction

The risk of cardiovascular disease (CVD) in patients with rheumatoid arthritis (RA) is 1.5–2 times higher than the general population. The fundamental risk factor for CVD is age, related to alterations at the arterial level. The aim of the study was to compare vascular age (VA) in RA patients under a strict treat-to-target (T2T) strategy with Osteoarthritis (OA) patients without strict follow up and to assess the influence of inflammaging (chronic, sterile, low-grade inflammation related to aging) and metabolic markers on VA.

Materials and Methods

This was an analytical cross-sectional study. Patients with RA (under a strict a T2T strategy) and OA patients without strict clinical follow-up were included. Patients with a history of uncontrolled hypertension, CVD, and/or current smoking were excluded. Sociodemographic, physical activity, and toxic exposure data were obtained. Waist-hip ratio and body mass index (BMI) were measured. DAS-28 (RA) and inflammatory markers, lipid profile, and glycaemia were analyzed. Pulse wave velocity (PWV) was measured (oscillometric method, Arteriograph-TensioMed®). VA was calculated based on PWV. Eleven components of inflammaging [six interleukins, three metalloproteinases (MMP), and two tissue inhibitors of metalloproteinases (TIMP)] were evaluated (Luminex® system). Univariate and bivariate analyzes (Mann Whitney U and chi-square) and correlations (Spearmans Rho) were done to compare the two groups.

Results

A total of 106 patients (74% women) were included, 52/RA and 54/OA. The mean age was 57 (Interquartile range - IQR 9 years). The BMI, waist circumference, and weight were higher in patients with OA (p < 0.001). RA patients had low disease activity (DAS-28-CRP). There were no differences in VA, inflammaging nor in PWV between the two groups. VA had a positive, but weak correlation, with age and LDL. In group of RA, VA was higher in those who did not receive methotrexate (p = 0.013). LDL levels correlated with MMP1, TIMP1, and TIMP2.

Conclusions

When comparing RA patients with low levels of disease activity with OA patients with poor metabolic control, there are no differences in VA. Furthermore, methotrexate also influences VA in RA patients. This shows that implemented therapies may have an impact on not only the inflammatory state of the joint but also CVD risk.

Novel Approaches to Anti-atherosclerotic Therapy: Cell-based Models and Herbal Preparations (Review of Our Own Data)

Atherosclerosis is a chronic arterial disease characterized by vascular inflammation, accumulation of lipids in the arterial wall, and formation and growth of atherosclerotic plaques followed by ischemia. In subclinical atherosclerosis, cholesterol retention in subendothelial cells leads to induction of local inflammation, generation of foam cells and lesion formation, followed by a chain of other pathogenic events. Atherosclerotic progression can frequently be fatal, since plaque rupture may lead to thrombosis and acute events, such as myocardial infarction, stroke and sudden death. Traditional anti-atherosclerotic therapy is mainly focused on improving the blood lipid profile and does not target various stages of plaque progression. Obviously, treating the disease at initial stages is better than beginning treatment at advanced stages and, in that regard, current atherosclerosis management can be improved. Cholesterol retention is an important component of atherogenesis that precedes plaque formation. Therapeutic targeting of cholesterol retention may be beneficial for preventing further atherogenic progression. For this purpose, we suggest using herbal preparations due to good tolerability and suitability for long-lasting treatment. We developed test systems based on cultured human intimal aortic cells for rapid screening of potential anti-atherogenic drugs. With the help of these test systems, we selected several natural substances with significant anti-atherogenic activity and further use these compounds to prepare herbal preparations for anti-atherosclerotic therapy. These preparations were clinically tested and showed good safety and a potent anti-atherogenic potential.

Transforming growth factor-β3 regulates cell junction restructuring via MAPK-mediated mRNA destabilization and Smad-dependent protein degradation of junctional adhesion molecule B (JAM-B)

Junctional adhesion molecule-B (JAM-B) is found between Sertoli cells at the blood-testis barrier (BTB) as well as between Sertoli and germ cells at the apical ectoplasmic specializations (ES) in the testis. The expression of JAM-B is tightly regulated to modulate the passage of spermatocytes across the BTB as well as the release of mature spermatozoa from the seminiferous epithelium. Transforming growth factor beta (TGF-β) family is implicated in the regulation of testicular cell junction dynamics during spermatogenesis. This study aims to investigate the effects of TGF-β3 on the expression of JAM-B as well as the underlying mechanisms on how TGF-β3 regulates JAM-B expression to facilitate the disassembly of the BTB and apical ES. Our results revealed that TGF-β3 suppresses JAM-B at post-transcriptional and post-translational levels. Inhibitor, siRNA knockdown and co-immunoprecipitation have shown that TGF-β3 induces JAM-B protein degradation via ubiquitin-proteasome pathway. Immunofluorescence staining further confirmed that blockage of ubiquitin-proteasome pathway could abrogate TGF-β3-induced loss of JAM-B at the cell-cell interface. siRNA knockdown and immunofluorescence staining also demonstrated that activation of Smad signaling is required for TGF-β3-induced JAM-B protein degradation. In addition, TGF-β3 reduces JAM-B mRNA levels, at least in part, via post-transcriptional regulation. mRNA stability assay has confirmed that TGF-β3 promotes the degradation of JAM-B transcript and TGF-β3-mediated mRNA destabilization requires the activation of ERK1/2 and p54 JNK signal cascades. Taken together, TGF-β3 significantly downregulates JAM-B expression via post-transcriptional and post-translational modulation and results in the disruption of BTB and apical ES.

Astrocyte elevated gene-1 is associated with metastasis in head and neck squamous cell carcinoma through p65 phosphorylation and upregulation of MMP1

Background

The survival rate of head and neck squamous cell carcinoma (HNSCC) at advanced stage is poor, despite contemporary advances in treatment modalities. Recent studies have indicated that astrocyte elevated gene-1 (AEG-1), a single transmembrane protein without any known functional domains, is overexpressed in various malignancies and is implicated in both distant metastasis and poor survival.

Results

High expression of AEG-1 in HNSCC was positively correlated with regional lymph node metastasis and a poor 5-year survival rate. Knockdown of AEG-1 in HNSCC cell lines reduced their capacity for colony formation, migration and invasion. Furthermore, decreased tumor volume and metastatic foci were observed after knockdown of AEG-1 in subcutaneous xenografts and pulmonary metastasis assays in vivo, respectively. We also demonstrated that AEG-1 increased phosphorylation of the p65 subunit of NF-κB, and regulated the expression of MMP1 in HNSCC cells. Moreover, compromised phosphorylation of the p65 (RelA) subunit of NF-κB at serine 536 was observed upon silencing of AEG-1 in both HNSCC cell lines and clinical specimens.

Conclusion

High expression of AEG-1 is associated with lymph node metastasis and its potentially associated mechanism is investigated.

Amentoflavone inhibits UVB-induced matrix metalloproteinase-1 expression through the modulation of AP-1 components in normal human fibroblasts

Amentoflavone is a well-known biflavonoid that has diverse biological effects. Previously, we reported that amentoflavone suppressed UVB-induced matrix metalloproteinase-1 (MMP-1) expression in normal human fibroblasts (NHF). We investigated the effects of amentoflavone on UVB-induced MMP-1 expression in order to elucidate its mode of action. NHF were treated with amentoflavone for indicated times and doses with UVB irradiation. The expressions of MMP-1 gene and protein were determined by RT-PCR and ELISA, respectively. MAP kinase phosphorylation and the expression of c-Fos protein were determined by Western blot. The treatment of amentoflavone completely blocked the upregulation of MMP-1 which is induced by UVB irradiation in HaCaT-NHF co-culture in a dose-dependent manner as well as in NHF monoculture. Also, amentoflavone inhibited UVB-induced activation of extracellular signal-regulated kinase (ERK) without changing total ERK protein level, and did not affect p38 or JNK activation. Finally, AP-1 transcription factor components, phospho-c-Jun and c-Fos protein expressions were decreased by amentoflavone treatment. The major finding of this study shows that amentoflavone inhibits intracellular cell signaling ERK pathway leading to the prevention of MMP-1 expression in human skin fibroblasts. Therefore, these results strongly suggest that amentoflavone should be investigated as a potential agent for the prevention and the treatment of skin photoaging.

Cholesterol, a Major Component of Caveolae, Down-regulates Matrix Metalloproteinase-1 Expression through ERK/JNK Pathway in Cultured Human Dermal Fibroblasts

BACKGROUND

Cholesterol is a major component of specialized membrane microdomains known as lipid rafts or caveolae, which modulate the fluidity of biological membranes. Membrane cholesterol therefore plays an important role in cell signaling and vesicular transport.

OBJECTIVE

In this study, we investigated the effects of cholesterol on matrix metalloproteinase-1 (MMP-1) expression in human dermal fibroblasts.

METHODS

MMP-1 mRNA and protein expression were determined by RT-PCR and Western blotting, respectively. AP-1 DNA binding activity was detected by electrophoretic mobility shift assays. The amount of cholesterol was analyzed by cholesterol assay kit.

RESULTS

We observed that MMP-1 mRNA and protein expression was dose-dependently decreased by cholesterol treatment. In contrast, cholesterol depletion by a cholesterol depletion agent, methyl-beta-cyclodextrin (MβCD) in human dermal fibroblasts, increased MMP-1 mRNA and protein expression in a dose-dependent manner. Also, we investigated the regulatory mechanism of MβCD-induced MMP-1 expression: cholesterol depletion by MβCD, activated ERK1/2 and JNK, but not p38 MAPK cascade, and it also significantly increased c-Jun phosphorylation, c-Fos expression and activator protein-1 binding activity. Furthermore, the inhibition of ERK or JNK with specific chemical inhibitors prevented MβCD-induced MMP-1 expression, which indicates that ERK and JNK play an important role in cholesterol depletion-mediated MMP-1 induction. In addition, MβCD-induced phosphorylation of ERK and JNK and MMP-1 expression were suppressed by cholesterol repletion.

CONCLUSION

Our results suggest that cholesterol regulates MMP-1 expression through the control of ERK and JNK activity in human dermal fibroblasts.

Sodium lactate increases LPS-stimulated MMP and cytokine expression in U937 histiocytes by enhancing AP-1 and NF-kappaB transcriptional activities

The plasma lactate concentration in patients with obesity and type 2 diabetes is often higher than that in nondiabetic individuals. Although it is known that increased lactate concentration is an independent risk factor for developing type 2 diabetes, the underlying mechanisms are not well understood. Because inflammation plays an important role in the development of type 2 diabetes, we postulated that increased lactate level might contribute to the pathogenesis of type 2 diabetes by enhancing inflammation. In the present study, we demonstrated that preexposure of U937 macrophage-like cells to sodium lactate increased LPS-stimulated matrix metalloproteinase (MMP)-1, IL-1beta, and IL-6 secretion. Augmentation of LPS-stimulated MMP-1 secretion was diminished when sodium lactate was replaced by lactic acid that reduced pH in the culture medium. Furthermore, quantitative real-time PCR indicated that the increased secretion of MMP-1, IL-1beta, and IL-6 was due to increased mRNA expression. To explore the underlying signaling mechanism, blocking studies using specific inhibitors for NF-kappaB and MAPK cascades were performed. Results showed that blocking of either NF-kappaB or MAPK pathways led to the inhibition of MMP-1, IL-1beta, and IL-6 expression stimulated by sodium lactate, LPS, or both. Finally, electrophoretic mobility shift assays showed a synergy between sodium lactate and LPS on AP-1 and NF-kappaB transcriptional activities. In conclusion, this study has demonstrated for the first time that sodium lactate and LPS exert synergistic effect on MMP and cytokine expression through NF-kappaB and MAPK pathways and revealed a novel mechanism potentially involved in the development of type 2 diabetes and its complications.