Elevated matrix metalloproteinase-9 in patients with systemic sclerosis

Proinflammatory effects of diesel exhaust nanoparticles on scleroderma skin cells

Autoimmune diseases are complex disorders of unknown etiology thought to result from interactions between genetic and environmental factors. We aimed to verify whether environmental pollution from diesel engine exhaust nanoparticulate (DEP) of actually operating vehicles could play a role in the development of a rare immune-mediated disease, systemic sclerosis (SSc), in which the pathogenetic role of environment has been highlighted. The effects of carbon-based nanoparticulate collected at the exhaust of newer (Euro 5) and older (Euro 4) diesel engines on SSc skin keratinocytes and fibroblasts were evaluated in vitro by assessing the mRNA expression of inflammatory cytokines (IL-1α, IL-6, IL-8, and TNF-α) and fibroblast chemical mediators (metalloproteases 2, 3, 7, 9, and 12; collagen types I and III; VEGF). DEP was shown to stimulate cytokine gene expression at a higher extent in SSc keratinocytes versus normal cells. Moreover, the mRNA gene expression of all MMPs, collagen types, and VEGF genes was significantly higher in untreated SSc fibroblasts versus controls. Euro 5 particle exposure increased the mRNA expression of MMP-2, -7, and -9 in SSc fibroblasts in a dose dependent manner and only at the highest concentration in normal cells. We suggest that environmental DEP could trigger the development of SSc acting on genetically hyperreactive cell systems.

B lymphocytes and B-cell activating factor promote collagen and profibrotic markers expression by dermal fibroblasts in systemic sclerosis

Introduction

B lymphocytes might play a pathogenic role in dermal fibrosis in systemic sclerosis (SSc). B-cell activating factor (BAFF), a key cytokine for B-cell activation, is increased in the serum and the skin of patients with SSc. However, the ability of B cells directly to stimulate dermal fibroblasts and the role of BAFF are not fully understood. We therefore investigated the involvement of B cells and BAFF in the expression of collagen and profibrotic markers by dermal fibroblasts.

Methods

Cocultures of blood B cells from healthy blood donors and normal or SSc dermal fibroblasts stimulated with anti-IgM and BAFF were performed. Alpha-SMA, TIMP1, MMP9, COL1A1, COL1A2, and COL3A1 mRNA expression were determined by quantitative RT-PCR. Soluble collagen, BAFF, IL-6, IL-1β, TGF-β1, and CCL2 protein secretion were assessed.

Results

Coculture of blood B cells and dermal fibroblasts isolated from SSc patients induced IL-6, TGF-β1, CCL2, and collagen secretion, as well as Alpha-SMA, TIMP1, and MMP9 expression in dermal fibroblasts. Transwell assays demonstrated that this induction was dependent on cell-cell contact. Addition of anti-IgM and BAFF to the coculture increased IL-6, CCL2, TGF-β1, and collagen secretion. B cell- and BAFF-induced collagen secretion was highly reduced by anti-TGF-β1 antibodies.

Conclusions

Our results showed for the first time a direct role of B cells on the production of collagen by dermal fibroblasts, which is further enhanced by BAFF. Thus, these results demonstrate a new pathogenic role of B cells and BAFF in fibrosis and systemic sclerosis.

Circulating biomarkers of interstitial lung disease in systemic sclerosis

Interstitial lung disease (ILD) is a major cause of morbidity and mortality in patients with systemic sclerosis (SSc). Although a large proportion of SSc patients have only limited interstitial involvement with an indolent course, in a significant minority ILD is progressive, requiring prompt treatment and careful monitoring. One of the main challenges for the clinician treating this highly variable disease is the early identification of patients at risk of progressive ILD, while avoiding potentially toxic treatments in those whose disease is inherently stable. Easily available and repeatable biomarkers that allow estimation of the risk of ILD progression and early response to treatment are highly desirable. In this paper, we review the evidence for circulating biomarkers with potential roles in diagnosis, monitoring of disease activity, or determining prognosis. Peripheral blood biomarkers offer the advantages of being readily obtained, non-invasive, and serially monitored. Several possible candidates have emerged from studies performed so far, including SP-D, KL-6, and CCL18. Presently however, there are few prospective studies evaluating the predictive ability of prospective biomarkers after adjustment for disease severity. Future carefully designed, prospective studies of well characterised patients with ILD, with optimal definition of disease severity and outcome measures are needed.

Application of biomarkers to clinical trials in systemic sclerosis

Important clinical advances in the treatment of systemic sclerosis have been made, yet fibrotic disease remains largely untreatable. Optimal design of clinical trials to test new therapeutics for fibrotic disease features has suffered from dual difficulties in patient selection and patient evaluation. Patient selection for entry into trials for treatment of interstitial lung disease and/or skin fibrosis is challenged by the natural history of the disease, which stabilizes in some patients while relentlessly progressing in others, and our lack of good clinical markers to distinguish between these trajectories. Patient evaluation is made difficult, particularly in skin disease, by the inherent difficulty in quantifying the extent of disease. Biomarkers hold the potential to solve many of these problems as surrogate outcome measures and as markers for disease progression. Identified biomarkers may have the potential to graduate to surrogate outcome singly or, more likely, in combination. Predictive biomarkers are still largely unknown.

Upregulated expression of matrix metalloproteinases and tissue inhibitors of matrix metalloproteinases in BALB/c mouse brain challenged with Japanese encephalitis virus

BACKGROUND

Uncontrolled immune responses in the nervous system are potentially damaging following Japanese encephalitis virus (JEV) infection. Matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs) act together to control the proteolysis of extracellular matrix. Disbalances in the MMP/TIMP system during virally induced neurodegenerative processes and inflammations are responsive to changes in the progression of diseases.

METHODS

The expression of MMP-2, MMP-7, MMP-9, TIMP-1, and TIMP-3 in JEV-infected mouse brain was analyzed by RT-PCR for semiquantitation and ELISA for estimation of protein along with brain histopathology at different days postinoculation (dpi). Gelatin gel zymography was performed for MMP-2 and MMP-9 activities.

RESULTS

In the virus-infected group, expression of MMP-2, MMP-7, MMP-9, TIMP-1, and TIMP-3 was found to be increased from 1 dpi to 6 dpi as compared to controls by both RT-PCR and ELISA. The expressions of MMPs and TIMPs at mRNA and protein levels were in concordance with each other. Post hoc multiple comparison analysis between days revealed that, in the virus-infected groups, significant increases (p < 0.05) in MMP and TIMP levels were observed between various dpi at both mRNA and protein levels. Only the MMP-7 protein level at 6 dpi was not significant compared to 5 dpi (p = 0.99).

CONCLUSION

Overexpression of MMPs and TIMPs is associated with disease severity in the central nervous system (CNS) during JEV infection. Our results showed that JEV infection can alter the expression of MMPs and TIMPs in the CNS. Thus, assessing these important immune mediators in CNS infection appears to play an important role in the development of symptoms and may help to understand the JEV-induced neurological disorders. More studies are required on this important enzymatic system to study their role in immune mediated pathogenesis.

Matrix metalloproteinases

Remodeling of extracellular matrix is crucial for many physiological (cell migration, proliferation, growth, and development) and pathological (remodeling of heart, carcinogenesis, metastasis, etc.) events. Thus, the interaction between cells and extracellular matrix plays a key role in normal development and differentiation of organism and many pathological states as well. Changes in extracellular matrix are regulated by a system of proteolytic enzymes that are responsible for proteolysis of huge quantity of extracellular matrix components. Matrix metalloproteinases (MMPs) represent the main group of regulating proteases in ECM. Ability of matrix metalloproteinases to modify the structural integrity of tissues is essential for certain aspects of normal physiology and pathology. The ability to process molecules such as growth factors, receptors, adhesion molecules, other proteinases, and proteinase inhibitors makes MMPs potent controllers of physiological and pathological events in the cell microenvironment. Overactivation of MMPs has been implicated in numerous disease states.

Association of MMP-2 and MMP-9 with clinical outcome of neurocysticercosis

Matrix metalloproteinases (MMPs) are the major endopeptidases involved in proteolysis of blood brain barrier (BBB) during central nervous system (CNS) infections. The present study detected serum levels and activities of MMP-2 and MMP-9 in patients with neurocysticercosis (NCC) and their association with symptomatic disease. In total, 68 individuals with NCC (36 symptomatic patients with active seizures and 32 asymptomatic individuals) and 37 healthy controls were enrolled for the study. Serum MMP-2 and MMP-9 levels and their activities were measured by ELISA and gel zymography respectively. Mean serum MMP-2 levels (ng/ml) were higher both in asymptomatic and symptomatic NCC cases compared to healthy controls. However, significantly higher levels of serum MMP-9 (ng/ml) were detected only in symptomatic NCC patients compared to asymptomatic NCC cases and healthy controls. Levels of both MMPs positively correlated with symptomatic NCC. Serum MMP-2 activities were significantly higher in symptomatic and asymptomatic NCC compared to healthy controls whereas serum MMP-9 activity was significantly associated with symptomatic NCC compared to healthy controls and asymptomatic NCC. In conclusion, the elevated level of MMP-9 in serum appears to play an important role in the development of symptoms i.e. active seizures in patients with NCC. However, further studies are needed to elucidate its precise role in disease pathogenesis.

Elevated MMP-7 levels in patients with systemic sclerosis: correlation with pulmonary involvement

BACKGROUND

Fibrosis is characterized by an excessive accumulation of connective tissue because of an imbalance between synthesis and degradation of extracellular matrix proteins. Systemic sclerosis (SSc) is a prototypic chronic inflammatory disease leading to a severe fibrosis of the skin and many internal organs. QUESTIONS ADDRESSED: We investigated whether serum MMP-7 levels reflect the activity of the fibrotic reaction in systemic sclerosis.

EXPERIMENTAL DESIGN

Serum samples were obtained from 123 patients with systemic sclerosis. MMP-serum levels of all patients with SSc were compared with age-matched healthy controls.

RESULTS

Significantly increased median serum MMP-7 levels were found in patients with SSc when compared with controls. The median MMP-7 serum level of patients with lung fibrosis (LF) was significantly higher compared with those without LF. Accordingly, patients with dyspnea and DLCO (diffusion capacity of the lung for carbon monoxide) levels below 60% showed significantly higher median MMP-7 levels.

CONCLUSIONS

Elevated MMP-7 levels are associated with an advanced stage of SSc and LF. These data suggest that in SSc MMP-7 is involved in the process of fibrotic tissue remodelling.

Effects of streptolysin o on extracellular matrix gene expression in normal human epidermal keratinocytes

ML-05 is a non-hemolytic form of streptolysin O, the membrane-damaging extracellular toxin produced by certain streptococci. ML-05 stimulates keratinocyte migration and proliferation in wound-healing scratch assays and promotes wound healing in a human skin organ culture wound model. Pathway-focused DNA microarrays were used to elucidate ML-05's mechanism of action in wound healing processes. Normal human epidermal keratinocytes (NHEK) were treated with varying concentrations of ML-05 for 24 hours, followed by RNA extraction and cRNA production. Gene expression profiling utilized microarrays containing nucleic acid probes for 113 extracellular matrix (ECM) genes. Microarrays yielded 6 upregulated and 4 downregulated genes with ≥2-fold changes and p<0.05 in t-tests. Quantitative real-time polymerase chain reactions (qPCR) were used to verify gene regulation. Upregulated genes of interest were VCAN (formerly CSPG2, encoding versican), CD44 (encoding hyaluronan receptor), ICAM1 (encoding intercellular adhesion molecule-1) and CTGF (encoding connective tissue growth factor). All four upregulated genes encode proteins involved in promoting keratinocyte migration and proliferation. Downregulated genes of interest were MMP9 (encoding matrix metalloproteinase 9) and SPP1 (encoding osteopontin). ML-05 may enhance wound healing through the expression of specific genes encoding proteins capable of promoting keratinocyte migration, proliferation, and other activities related to maintaining ECM structure and function.

Role of Plasma MMP 9 levels in the Pathogenesis of Chronic Pancreatitis

Pancreatic fibrosis is a key pathological feature in the etiology of chronic pancreatitis that leads to obliteration of exocrine and endocrine pancreatic tissues and its replacement by fibrous tissue resulting in clinical manifestations. Matrix metalloproteinase 9 is a member of the MMP family that is also known as gelatinase B, degrades type IV collagen of extracellular matrix and basal membrane. The present study is aimed at evaluating the clinical significance of plasma concentration of MMP-9 in chronic pancreatitis. The samples were obtained from 112 chronic pancreatitis patients and an equal number of age and sex matched healthy controls. MMP-9 levels were quantitatively measured by ELISA assay. Statistical analysis was applied to test the significance of results. The present study revealed a significant increase of plasma MMP 9 levels in chronic pancreatitis patients compared to control subjects. Elevated levels were also observed in all the patient groups compared to control subjects with regard to sex, age, addictions etc. MMP-9 degrades the type IV collagens in normal basement membrane, which in turn activates the pancreatic stellate cells which promote the development of pancreatitic fibrosis. Thus, elevated plasma levels of MMP-9 may act as a susceptibility factor for the development of chronic pancreatitis.

Ability of trichloroethylene metabolite to promote immune pathology is strain-specific

Chronic low-level exposure to the environmental pollutant trichloroethylene has been shown to promote autoimmune disease in association with CD4(+) T-lymphocyte activation in lupus-prone MRL(+/+) mice. One of the primary metabolites of trichloroethylene, trichloroacetaldehyde hydrate (TCAH), was similarly shown to increase the percentage of IFNgamma-producing CD4(+) T-lymphocytes when added to the drinking water of MRL(+/+) mice. In addition, TCAH-treated MRL(+/+) mice developed skin inflammation and alopecia. In the present study TCAH was tested for its ability to accelerate the development of alopecia in C3H/HeJ mice which tend to develop the disorder spontaneously late in life. In contrast to MRL(+/+) mice, C3H/HeJ mice treated with TCAH did not develop alopecia at an increased rate. In addition, TCAH did not promote the expansion of activated IFNgamma-producing CD4(+) T-lymphocytes in C3H/HeJ mice. CD4(+) T-lymphocytes from TCAH-treated C3H/HeJ mice, unlike their MRL(+/+) counterparts, did not become resistant to activation-induced apoptosis following in vivo exposure to TCAH. Taken together, it appears that the ability of TCAH to promote immune-mediated pathology is strain-specific and may require an autoimmune-prone genetic background.

Evaluation of metalloproteinases 2 and 9 and their inhibitors in physiologic and pre-eclamptic pregnancy

Matrix metalloproteinases (MMPs) are a family of zinc and calcium-dependent endopeptidases involved in remodeling and physiological homeostasis of extracellular matrix (ECM). The metalloproteinases activity is predominantly modulated by specific tissue inhibitors of matrix metalloproteinases (TIMPs). The balance between MMPs and TIMPs is likely to play an important role in remodeling uterine arteries in pregnancy, and it may represent means by which vasodilatation is maintained in later pregnancy. Moreover, increased levels of MMPs and in particular MMP-2 play a role in the vascular alterations induced by hypertension. The aim of this study was the evaluation of MMP-2 and -9, along with their inhibitors TIMP-1 and -2, in pre-eclamptic women compared with normotensive pregnancy and non-pregnant women. Fourteen pre-eclamptic women were compared with 37 normotensive women in different gestational age and 21 non-pregnant women. Multiplexed sandwich enzyme-linked immunosorbent assay was used to measure MMPs and TIMPs simultaneously. MMP-2 levels were significantly higher in pre-eclamptic women vs. both non-pregnant and physiologic pregnant women. MMP-9 concentrations were significantly higher in physiologic pregnant vs. non-pregnant women. The serum levels of TIMP-1 were significantly higher in pre-eclamptic vs. both non-pregnant and physiologic pregnant women. TIMP-2 values were higher in physiologic pregnant women and pre-eclamptic women vs. non-pregnant women. A positive correlation between MMP-9 values and gestational age was observed in normal pregnant women. Results of the present investigation confirm that MMP-2 and TIMP-1 values are significantly higher in preeclampsia. We confirm that the modification of the fine balance between MMPs and their inhibitors plays a greater role in the structural and functional vascular changes of women with complicated pregnancies.

Correlation of Biomarkers of Endothelium Dysfunction and Matrix Remodeling in Patients with Systemic Sclerosis

Objective.

Systemic sclerosis (SSc) is a multisystem disease characterized by microvascular dysfunction and excessive fibrosis. However, the relationship between these 2 features remains unclear. Endothelial dysfunction can be assessed by quantifying plasma asymmetric dimethylarginine (ADMA), an endogenous inhibitor of endothelial nitric oxide synthase. Matrix remodeling can be assessed by quantifying serum tissue inhibitor of matrix metalloproteinases-1 (TIMP-1). Both biomarkers are elevated in patients with SSc. Our objective was to test whether plasma ADMA is correlated with serum TIMP-1.

Methods.

We enrolled 91 subjects, 39 patients with SSc, 28 patients with primary Raynaud’s phenomenon (RP), and 24 healthy volunteers. Plasma ADMA concentrations were measured by liquid chromatography-tandem mass spectrometry. Serum TIMP-1 concentrations were determined by ELISA.

Results.

Mean ADMA concentrations were higher in patients with SSc (0.68 μM ± 0.12) than in patients with primary RP or healthy volunteers (respectively, 0.56 μM ± 0.14 and 0.62 μM ± 0.12; p = 0.002). Median serum TIMP-1 concentrations were increased in patients with SSc compared to primary RP and healthy volunteers [12 (9–15), 11 (8–13), and 10 (7–13) nM, respectively; p = 0.05]. In the SSc group, we observed a statistically significant correlation between plasma ADMA and serum TIMP-1 (r = 0.34, p = 0.035).

Conclusion.

These data are consistent with our hypothesis of an association of endothelial dysfunction and matrix remodeling in scleroderma spectrum disorders.

Circulating tissue inhibitor of matrix metalloproteinase-4 (TIMP-4) in systemic sclerosis patients with elevated pulmonary arterial pressure

Decreased levels of matrix metalloproteinases (MMPs) or excess levels of their tissue inhibitors (TIMPs) may contribute to dysregulation of extracellular matrix turnover in systemic sclerosis (SSc). In a cross-sectional study of 106 SSc patients, we measured serum levels of TIMP-4 which is preferentially expressed in cardiovascular structures and searched for correlations with simultaneously performed echocardiography measurements of pulmonary artery systolic pressure (PASP), myocardial performance, and pulmonary function tests. TIMP-4, but not MMP-9, levels were significantly raised in patients with SSc than controls. However, in the subgroup of patients with PASP measurements lower to 40 mmHg (n = 69), TIMP-4 levels were comparable to controls irrespective of the presence of diffuse or limited skin involvement, or lung fibrosis. Individual PASP measurements suggestive of pulmonary hypertension were associated with increased TIMP-4 serum levels (P = .03), independently of age, extent of skin sclerosis, or lung fibrosis, suggesting a cardiopulmonary vasculature-specific role of TIMP-4 activation in SSc.

Relationship between matrix metalloproteinases/tissue inhibitors of matrix metalloproteinases systems and autoantibody patterns in systemic sclerosis

OBJECTIVE

Systemic sclerosis (SSc) is a connective tissue disease characterized by tissue fibrosis that reflects an imbalance between collagen production and degradation. Matrix metalloproteinases (MMPs) are a family of endopeptidases involved in the remodelling of extracellular matrix (ECM). This activity is controlled by tissue inhibitors of MMP (TIMPs). Aim of this study was the evaluation of MMP-9/TIMP-1 and MMP-2/TIMP-2 systems in patients with SSc.

DESIGN AND METHODS

SearchLight Human MMP Array 1 was used to measure MMPs and TIMPs in 32 SSc patients and 32 matched healthy controls.

RESULTS

SSc patients showed higher values of both MMP-9 and TIMP-1 in comparison with controls. The patients with anticentromere antibodies (ACA) positivity showed higher values of MMPs and TIMPs in comparison with either controls or the patients with anti-Scl70-positive antibodies.

CONCLUSION

Results of this investigation suggest that SSc patients with ACA positivity, after a primary fibrogenetic noxa, react with a more abundant release of MMP/TIMP, whereas patients with anti-Scl70 antibody show a normal response.

The X chromosome and systemic sclerosis

PURPOSE OF REVIEW

Similar to the majority of autoimmune rheumatic diseases, systemic sclerosis is characterized by a striking female predominance superimposed on a predisposing genetic background. At least two genetic mechanisms have been proposed that play a role in susceptibility to systemic sclerosis; firstly the maintenance of immune tolerance via genes on the X chromosomes and, secondly, fetal microchimerism. Based on these lines of evidence, experimental efforts have been most recently dedicated to investigating the role of X chromosome abnormalities (i.e. monosomy rates and inactivation patterns) in autoimmunity. We will review herein the most recent data on the role of the X chromosome in systemic sclerosis onset and discuss the potential implications.

RECENT FINDINGS

Women with systemic sclerosis manifest an enhanced rate of X monosomic cells in peripheral blood compared with healthy age-matched women. Furthermore, a severely skewed X chromosome inactivation pattern is found in women with systemic sclerosis.

SUMMARY

These observations, reproduced in other female-predominant autoimmune diseases, strongly support the role of the X chromosome in conferring susceptibility to tolerance breakdown and open novel scenarios to emphasize the unknown etiopathogenesis of systemic sclerosis. The implications of these findings will be discussed.

[Current pathophysiological aspects of systemic sclerosis]

Systemic scleroderma is characterized by a chronic inflammatory process of unknown etiology resulting in an increased deposition of connective tissue proteins in the involved organs. Involvement of the vascular system and the resulting fibrosis lead to atrophy and malfunction of the involved internal organs and the skin. Due to the development of new therapeutic concepts in particular with regard to the vascular involvement, the interaction between the vascular system and the connective tissue moves increasingly into focus. This review describes the major advancemades during recent years for the understanding of the pathophysiology of systemic scleroderma.

Matrix metalloproteinase-9 and autoimmune diseases

Matrix metalloproteinases (also named matrixin or MMPs) are a major group of enzymes that regulate cell-matrix composition by using zinc for their proteolytic activities. They are essential for various normal biological processes such as embryonic development, morphogenesis, reproduction tissue resorption, and remodeling. Metalloproteinases also play a role in pathological processes including inflammation, arthritis, cardiovascular diseases, pulmonary diseases and cancer. Herein we review the involvement of MMP-9 in a variety of autoimmune diseases including systemic lupus erythematosus, Sjogren's syndrome, systemic sclerosis, rheumatoid arthritis, multiple sclerosis, polymyositis and atherosclerosis. MMP-9 plays either a primary or secondary role in each one of those autoimmune diseases by its up or down-regulation. It is not expressed constantly but rather is induced or suppressed by many regulating molecules. This feature of MMP-9 along with its involvement in disease pathogenesis turns it into a target for therapy of autoimmune diseases.

The length of CpG islands is associated with the distribution of Alu and L1 retroelements

Alu and L1 retroelements have been suggested to initiate the spread of CpG methylation. In this study, the spread of CpG methylation was estimated based on the distance between the CpG islands and the nearest retroelements. All human genes (23,116) were examined and the correlations between the length of the CpG islands and the distance and density of the confronting retroelements were examined using nonoverlapping 5-kb windows. There was a linear relationship between the length of the CpG islands and the density of the Alu elements and an inverse relationship between the CpG islands and the L1 elements located more distantly, suggesting a suppressive effect of the Alu's on the spread of L1 methylation. Methylation analysis of the transitional CpG sites between the CpG islands and the nearest retroelements upstream of 16 genes was then carried out using DNA preparations from 11 different human tissues. Methylation-variable transitional CpGs were observed for the selected genes and the different tissues.