Evaluation of gelatinases and IL-6 in the cerebrospinal fluid of patients with optic neuritis, multiple sclerosis and other inflammatory neurological diseases

Three-year follow-up of rheumatoid meningitis with matrix metalloprotease-9 levels in the serum and cerebrospinal fluid as indicators of disease activity: A case report

Rheumatoid meningitis (RM) is an extra-articular complication of rheumatoid arthritis (RA). Although reports of RM sine arthritis exist, most patients with this presentation were diagnosed with RA within one year of RM onset. There are no established biomarkers reflecting the disease activity of RM. This case report highlights the elevation of matrix metalloprotease (MMP)-9 levels during the acute phase of RM and decline during remission. Additionally, this is the first case report of RA diagnosed three years after the onset of RM. It is important to further validate the utility of MMP-9 and conduct long-term follow-up of RM sine arthritis.

Matrix metalloproteinases (MMPs) family gene polymorphisms and the risk of multiple sclerosis: systematic review and meta-analysis

Background

Several studies have reported the association between polymorphisms in Matrix metalloproteinases (MMPs) gene family and risk of Multiple sclerosis (MS). However, the results have been inconsistent and inconclusive. To resolve this issue, here we performed a systematic review and meta-analysis of the MMP-91562 C/T (rs3918242), MMP-3 (− 1612 5A/6A), and MMP-2 (− 1306 C/T) polymorphisms and susceptibility to MS.

Methods

We conducted a comprehensive systematic search in the major electronic database, including Scopus and PubMed to look up for relevant studies published before December 2019 that surveyed the association between the MMP-91562 C/T (rs3918242), MMP-3 (− 1612 5A/6A), and MMP-2 (− 1306 C/T) polymorphisms and susceptibility to MS. The level of association between the polymorphisms and susceptibility to MS in the polled analysis was determined by calculating the odds ratio (OR) and the corresponding 95% confidence interval (CI).

Results

We found 15 studies containing 2430 MS subjects and 2304 controls. A statistically significant association was observed in the all five comparisons of the MMP-91562 C/T polymorphism and MS risk as follows: dominant model (OR = 1.62, 95% CI = 1.03–2.53, P = 0.03), recessive model (OR = 2.69, 95% CI = 1.68–4.29, P < 0.001), allelic model (OR = 1.51, 95% CI = 1–2.28, P = 0.04), TT vs. CC model (OR = 3.20, 95% CI = 1.87–5.46, P < 0.001), and CT vs. CC model (OR = 1.53, 95% CI = 1.02–2.28, P = 0.04).

Conclusions

Our meta-analysis revealed significant association of MMP-9 (− 1562 C/T) Single-nucleotide polymorphism (SNP) with MS susceptibility that increased the disease risk.

Remnant Epitopes Generating Autoimmunity: From Model to Useful Paradigm

Autoimmune diseases are defined as pathologies of adaptive immunity by the presence of autoantibodies or MHC-restricted autoantigen-reactive T cells. Because autoreactivity is a normal process based on mechanisms producing repertoires of antibodies and T cell receptors, crucial questions about disease mechanisms and key steps for interference have been outstanding. We defined 25 years ago the 'remnant epitopes generate autoimmunity' (REGA)-model in which extracellular proteases from innate immune cells generate autoantigens. Here, we refine the REGA-model, tested in diseases ranging from organ-specific autoimmune diseases to systemic lupus erythematosus. It now constitutes a paradigm in which remnant epitopes generate, maintain, and regulate autoimmunity; are dependent on genetic and epigenetic influences; are produced in a disease phase-specific manner; and have therapeutic implications when targeted.

Matrix metalloproteinases in the CNS: interferons get nervous

Matrix metalloproteinases (MMPs) have been investigated in context of chronic inflammatory diseases and demonstrated to degrade multiple components of the extracellular matrix (ECM). However, following several disappointing MMP clinical trials, recent studies have demonstrated unexpected novel functions of MMPs in viral infections and autoimmune inflammatory diseases in unanticipated locations. Thus, MMPs play additional functions in inflammation than just ECM degradation. They can regulate the activity of chemokines and cytokines of the immune response by precise proteolytic processing resulting in activation or inactivation of signaling pathways. MMPs have been demonstrated to cleave multiple substrates of the central nervous systems (CNS) and contribute to promoting and dampening diseases of the CNS. Initially, believed to be solely promoting pathologies, more than 10 MMPs to date have been shown to have protective functions. Here, we present some of the beneficial and destructive roles of MMPs in CNS pathologies and discuss strategies for the use of MMP inhibitors.

Profiling of metalloprotease activities in cerebrospinal fluids of patients with neoplastic meningitis

Background

Neoplastic invasion into leptomeninges and subarachnoid space, resulting in neoplastic meningitis (NM) is a fatal complication of advanced solid and hematological neoplasms. Identification of malignant involvement of the cerebrospinal fluid (CSF) early in the disease course has crucial prognostic and therapeutic implications, but remains challenging. As indicators of extracellular matrix (ECM) degradation and breakdown of the blood–brain-barrier, Matrix Metalloproteases (MMPs) and A Disintegrin and Metalloproteases (ADAMs) are potential analytes for cerebral pathophysiology and metastatic dissemination of tumor cells into the CSF.

Methods

We compared protease activities in CSF samples from patients with NM and control individuals using FRET-based metalloprotease substrates with distinct enzyme selectivity profiles in a real-time, multiplex approach termed “proteolytic activity matrix assay” (PrAMA). Protease activity dynamics can be tracked by fluorescence changes over time. By simultaneously monitoring a panel of 5 FRET-substrate cleavages, a proteolytic signature can be identified and analyzed to infer the activities of multiple specific proteases. Distinct patterns of substrate cleavage comparing disease vs. control samples allow rapid, reproducible and sensitive discrimination even in small volumes of CSF.

Results

Individual substrate cleavage rates were linked to distinct proteases, and PrAMA computational inference implied increased activities of MMP-9, ADAM8 and ADAM17 (4–5-fold on average) in CSF samples from NM patients that were inhibitable by the metalloprotease inhibitor batimastat (BB-94). The activities of these proteases correlated with blood–brain barrier impairment. Notably, CSF cell counts were not found to directly reflect the protease activities observed in CSF samples from NM patients; this may explain the frequent clinical observation of negative cytology in NM patients.

Conclusion

PrAMA analysis of CSF samples is a potential diagnostic method for sensitive detection of NM and may be suitable for the clinical routine.

Electronic supplementary material

The online version of this article (doi:10.1186/s12987-017-0070-5) contains supplementary material, which is available to authorized users.

Modeling Alexander disease with patient iPSCs reveals cellular and molecular pathology of astrocytes

Alexander disease is a fatal neurological illness characterized by white-matter degeneration and formation of Rosenthal fibers, which contain glial fibrillary acidic protein as astrocytic inclusion. Alexander disease is mainly caused by a gene mutation encoding glial fibrillary acidic protein, although the underlying pathomechanism remains unclear. We established induced pluripotent stem cells from Alexander disease patients, and differentiated induced pluripotent stem cells into astrocytes. Alexander disease patient astrocytes exhibited Rosenthal fiber-like structures, a key Alexander disease pathology, and increased inflammatory cytokine release compared to healthy control. These results suggested that Alexander disease astrocytes contribute to leukodystrophy and a variety of symptoms as an inflammatory source in the Alexander disease patient brain. Astrocytes, differentiated from induced pluripotent stem cells of Alexander disease, could be a cellular model for future translational medicine.

Circulating levels of matrix metalloproteinases and tissue inhibitors of matrix metalloproteinases during Japanese encephalitis virus infection

Matrix metalloproteinases (MMPs) are widely implicated in modulating blood brain barrier (BBB) integrity and affect the entry of peripheral immune cells into the central nervous system (CNS). The expression of MMPs is tightly regulated at the level of gene transcription, conversion of pro-enzyme to active MMPs and by the action of tissue inhibitors of metalloproteinases (TIMP). The crucial role of MMPs in inflammation indicates that perturbation of the MMP/TIMP balance decisively plays an important role in pathogenesis during viral encephalitis. The study was performed to evaluate the production of MMP-2, MMP-7, MMP-9, TIMP-1 and TIMP-3 in the sera of JEV i.e. GP 78668A (GP-78) infected BALB/c mouse model of encephalitis and gel zymography was performed for MMP-2 and MMP-9 activities. The estimation of MMP-2, MMP-7, MMP-9, TIMP-1, and TIMP-3 in JEV-infected mouse serum was analyzed by ELISA along with brain histopathology and immunohistochemistry. Evan's blue dye exclusion test was done to check the BBB integrity. Gelatin gel zymography was performed for MMP-2 and MMP-9 activities. We noticed an upregulated expression of MMPs in the sera of virus infected groups compared to controls at different days post inoculation (dpi). Post hoc analysis between days also reveals significant increase (p < 0.05) in virus infected groups with disease progression. In contrast, TIMPs expressions were significantly (p < 0.005) down regulated in the virus infected group. We provide preliminary evidence for a pattern of TIMP response in JEV infection distinct from that seen in acute inflammatory CNS conditions in JE, shown in our previous findings. Increased MMP-2 and MMP-9 activities were also found in a virus infected group with disease progression and are consistent with our previous finding of MMP-2 and MMP-9 activities in the CNS which clearly demonstrate worsen role of these immune mediators in JEV infection. This study will help to identify new targets for the therapeutic treatment of inflammatory mediated CNS disorders in JEV infection and may lead to the development of potential pharmacological targets in future.

Heterogeneity of serum gelatinases MMP-2 and MMP-9 isoforms and charge variants

The matrix metalloproteinases (MMPs) gelatinase A (MMP-2) and gelatinase B (MMP-9) are mediators of brain injury in multiple sclerosis (MS) and valuable biomarkers of disease activity. We applied bidimensional zymography (2-DZ) as an extension of classic monodimensional zymography (1-DZ) to analyse the complete pattern of isoforms and post-translational modifications of both MMP-9 and MMP-2 present in the sera of MS patients. The enzymes were separated on the basis of their isoelectric points (pI) and apparent molecular weights (Mw) and identified both by comparison with standard enzyme preparations and by Western blot analysis. Two MMP-2 isoforms, and at least three different isoforms and two different states of organization of MMP-9 (the multimeric MMP-9 and the N-GAL-MMP-9 complex) were observed. In addition, 2-DZ revealed for the first time that all MMP-9 and MMP-2 isoforms actually exist in the form of charge variants: four or five variants in the NGAL complex, more charge variants in the case of MMP-9; and five to seven charge variants for MMP-2. Charge variants were also observed in recombinant enzymes and, after concentration, also in sera from healthy individuals. Sialylation (MMP-9) and phosphorylation (MMP-2) contributed to molecular heterogeneity. The detection of charge variants of MMP-9 and MMP-2 in MS serum samples illustrates the power of 2-DZ and demonstrates that in previous studies MMP mixtures, rather than single molecules, were analysed. These observations open perspectives for better diagnosis and prognosis of many diseases and need to be critically interpreted when applying other methods for MS and other diseases.

On the structure and functions of gelatinase B/matrix metalloproteinase-9 in neuroinflammation

The blood-brain barrier (BBB) is a specific structure that is composed of two basement membranes (BMs) and that contributes to the control of neuroinflammation. As long as the BBB is intact, extravasated leukocytes may accumulate between two BMs, generating vascular cuffs. Specific matrix metalloproteinases, MMP-2 and MMP-9, have been shown to cleave BBB beta-dystroglycan and to disintegrate thereby the parenchymal BM, resulting in encephalomyelitis. This knowledge has been added to the molecular basis of the REGA model to understand the pathogenesis of multiple sclerosis, and it gives further ground for the use of MMP inhibitors for the treatment of acute neuroinflammation. MMP-9 is associated with central nervous system inflammation and occurs in various forms: monomers and multimers. None of the various neurological and neuropathologic functions of MMP-9 have been associated with either molecular structure or molecular form, and therefore, in-depth structure-function studies are needed before medical intervention with MMP-9-specific inhibitors is initiated.

Matrix metalloproteinases and their tissue inhibitors in serum and cerebrospinal fluid of children with Japanese encephalitis virus infection

The expression of matrix metalloproteinases (MMPs) is tightly regulated at the level of gene transcription, conversion of pro-enzyme to active MMPs, and the action of tissue inhibitors of metalloproteinases (TIMPs). The present study aimed to investigate the expression of some specific MMPs (2, 7, 9) and TIMPs (1, 2, 3) in serum and cerebrospinal fluid (CSF) of children with Japanese encephalitis virus (JEV) infection. Serum and CSF levels of MMPs and TIMPs in children with JEV infection and disease control (DC) were compared. The CSF and serum concentrations of MMP-2, TIMP-2 and TIMP-3 were significantly higher in children with JEV infection compared to DC. The concentration of MMP-9 in serum was significantly higher in children with JEV infection than in the DC and healthy control (HC), while in the CSF, no significant difference was observed compared to DC. The MMP-7 serum concentration was significantly higher in children with JEV infection compared to HC, but no significant difference was observed compared to DC. MMP-7 concentration was undetectable in CSF in both groups. The TIMP-1 CSF concentration was significantly higher, while the serum concentration was significantly lower, in children with JEV infection compared to DC. No correlation was found between the levels of each biomolecule measured in CSF and serum, suggesting that the levels in CSF represent local production within the CNS rather than production in the periphery. We also observed leucocytosis, mononuclear pleocytosis and elevated protein concentrations in the CSF of children with JEV infection compared to DC.

Zymography methods for visualizing hydrolytic enzymes

Zymography is a technique for studying hydrolytic enzymes on the basis of substrate degradation. It is a powerful, but often misinterpreted, tool yielding information on potential hydrolytic activities, enzyme forms and the locations of active enzymes. In this Review, zymography techniques are compared in terms of advantages, limitations and interpretations. With in gel zymography, enzyme forms are visualized according to their molecular weights. Proteolytic activities are localized in tissue sections with in situ zymography. In vivo zymography can pinpoint proteolytic activity to sites in an intact organism. Future development of novel substrate probes and improvement in detection and imaging methods will increase the applicability of zymography for (reverse) degradomics studies.

Multiple sclerosis: the role of cytokines in pathogenesis and in therapies

Multiple sclerosis, the clinical features and pathological correlate for which were first described by Charcot, is a chronic neuroinflammatory disease with unknown etiology and variable clinical evolution. Although neuroinflammation is a descriptive denominator in multiple sclerosis based on histopathological observations, namely the penetration of leukocytes into the central nervous system, the clinical symptoms of relapses, remissions and progressive paralysis are the result of losses of myelin and neurons. In the absence of etiological factors as targets for prevention and therapy, the definition of molecular mechanisms that form the basis of inflammation, demyelination and toxicity for neurons have led to a number of treatments that slow down disease progression in specific patient cohorts, but that do not cure the disease. Current therapies are directed to block the immune processes, both innate and adaptive, that are associated with multiple sclerosis. In this review, we analyze the role of cytokines in the multiple sclerosis pathogenesis and current/future use of them in treatments of multiple sclerosis.

Matrix metalloproteinase-7 and matrix metalloproteinase-9 in pediatric multiple sclerosis

Matrix metalloproteinases and their tissue inhibitors play a key role in the pathogenesis of adult-onset multiple sclerosis, and were suggested as biomarkers of response to interferon-β, an established treatment in multiple sclerosis. However, data regarding pediatric population are scarce. We determined serum levels of matrix metalloproteinase-7, matrix metalloproteinase-9, and tissue inhibitor of matrix metalloproteinase-1 in children, and evaluated effects of interferon-β therapy on these measures. Serum samples from 14 children with relapsing, remitting multiple sclerosis at baseline and at month 12, and from 15 controls, were collected. Interferon-β treatment was initiated in eight patients. Mean serum matrix metalloproteinase-9 levels and matrix metalloproteinase-9/tissue inhibitor of matrix metalloproteinase-1 ratio were higher in patients compared with controls, and were reduced significantly in treated patients at month 12, but did not change in untreated patients. Mean matrix metalloproteinase-7 levels were lower in patients compared with controls, and increased significantly in the treated group, but did not change significantly in the untreated group. In pediatric multiple sclerosis, a shift in matrix metalloproteinase-9/tissue inhibitor of matrix metalloproteinase-1 balance toward proteolytic activity is evident, and interferon-β therapy demonstrates a beneficial effect on this disturbed balance.

Kallikrein 6 regulates early CNS demyelination in a viral model of multiple sclerosis

Kallikrein 6 (Klk6) is a secreted serine protease that is elevated in active multiple sclerosis lesions and patient sera. To further evaluate the involvement of Klk6 in chronic progressive demyelinating disease, we determined its expression in the brain and spinal cord of SJL mice infected with Theiler's murine encephalomyelitis virus (TMEV) and assessed the effects of Klk6-neutralizing antibodies on disease progression. Klk6 RNA expression was elevated in the brain and spinal cord by 7 days postinfection (dpi). Thereafter, Klk6 expression persisted primarily in the spinal cord reaching a peak of fivefold over controls at mid-chronic stages (60 dpi-120 dpi). Significant elevations in Klk6 RNA were also induced in splenocytes stimulated with viral capsid proteins in vitro and in activated human acute monocytic leukemia cells. Klk6-neutralizing antibodies reduced TMEV-driven brain and spinal cord pathology and delayed-type hypersensitivity (DTH) responses when examined at early chronic time points (40 dpi). Reductions in spinal cord pathology included a decrease in activated monocytes/microglia and reductions in the loss of myelin basic protein (MBP). By 180 dpi, pathology scores no longer differed between groups. These findings point to regulatory activities for Klk6 in the development and progression of central nervous system (CNS) inflammation and demyelination that can be effectively targeted through the early chronic stages with neutralizing antibody.

Matrix metalloproteinases as therapeutic targets in protozoan parasitic infections

Matrix metalloproteinases (MMPs) are associated with processes of tissue remodeling and are expressed in all infections with protozoan parasites. We here report the status of MMP research in malaria, trypanosomiasis, leishmaniasis and toxoplasmosis. In all these infections, the balances between MMPs and endogenous MMP inhibitors are disturbed, mostly in favor of active proteolysis. When the infection is associated with leukocyte influx into specific organs, immunopathology and collateral tissue damage may occur. These pathologies include cerebral malaria, sleeping sickness (human African trypanosomiasis), Chagas disease (human American trypanosomiasis), leishmaniasis and toxoplasmic encephalitis in immunocompromised hosts. Destruction of the integrity of the blood-brain barrier (BBB) is a common denominator that may be executed by leukocytic MMPs under the control of host cytokines and chemokines as well as influenced by parasite products. Mechanisms by which parasite-derived products alter host expression of MMP and endogenous MMP inhibitors, have only been described for hemozoin (Hz) in malaria. Hence, understanding these interactions in other parasitic infections remains an important challenge. Furthermore, the involved parasites are also known to produce their own metalloproteinases, and this forms an extra stimulus to investigate MMP inhibitory drugs as therapeutics. MMP inhibitors (MMPIs) may dampen collateral tissue damage, as is anecdotically reported for tetracyclines as MMP regulators in parasite infections.

Expression of matrix metalloproteinases and their tissue inhibitors in the serum and cerebrospinal fluid of patients with meningitis

Meningitis is associated with an imbalance between matrix metalloproteinases (MMPs) and endogenous tissue inhibitors of MMP (TIMPs). Serum and CSF were collected prospectively from all patients with meningitis between January 2008 and December 2008 to measure the concentrations of MMP/TIMP in those patients who underwent a lumbar puncture for a presumptive diagnosis of meningitis. A total of 199 patients were enrolled into the study. The concentrations of CSF MMP-9 and TIMP-1 were significantly higher in the meningitis group compared with the control group (p 0.032 and p <0.001, respectively). However, the CSF TIMP-4 levels were significantly lower in the meningitis groups compared with the control groups (p <0.001). Patients with bacterial meningitis had higher CSF MMP-9 and TIMP-1 levels than those who had aseptic meningitis and controls. Patients with various infectious meningitis etiologies tended to have higher CSF MMP-9 expression by gelatin zymography when compared with the controls. In conclusion, MMP/TIMP system dysregulation was found in patients with meningitis, and CSF MMP and TIMP might act as novel indicators in patients with meningitis.

The multiple sclerosis degradome: enzymatic cascades in development and progression of central nervous system inflammatory disease

An array of studies implicate different classes of protease and their endogenous inhibitors in multiple sclerosis (MS) pathogenesis based on expression patterns in MS lesions, sera, and/or cerebrospinal fluid (CSF). Growing evidence exists regarding their mechanistic roles in inflammatory and neurodegenerative aspects of this disease. Proteolytic events participate in demyelination, axon injury, apoptosis, and development of the inflammatory response including immune cell activation and extravasation, cytokine and chemokine activation/inactivation, complement activation, and epitope spreading. The potential significance of proteolytic activity to MS therefore relates not only to their potential use as important biomarkers of disease activity, but additionally as prospective therapeutic targets. Experimental data indicate that understanding the net physiological consequence of altered protease levels in MS development and progression necessitates understanding protease activity in the context of substrates, endogenous inhibitors, and proteolytic cascade interactions, which together make up the MS degradome. This review will focus on evidence regarding the potential physiologic role of those protease families already identified as markers of disease activity in MS; that is, the metallo-, serine, and cysteine proteases.

Matrix metalloproteinase dysregulation in HIV infection: implications for therapeutic strategies

The emerging role of immune activation and inflammation in the pathogenesis of human immunodeficiency virus (HIV) disease has stimulated the search for new approaches for managing HIV infection. Recent evidence suggests that an imbalance between matrix metalloproteinases (MMPs) and endogenous tissue inhibitors of MMPs (TIMPs) might contribute to HIV-associated pathology by inducing remodelling of the extracellular matrix. Here, we discuss the evidence and the potential mechanisms for altered MMP or TIMP function in HIV infection and disease. Furthermore, we outline the possible medical implications for the use of compounds that target MMP activity, and we propose that antiretroviral drugs, particularly HIV protease inhibitors (PIs), and compounds with anti-inflammatory properties, such as statins, natural omega-3 fatty acids and tetracyclines, which inhibit MMP function, might represent useful therapeutic approaches to mitigate potential MMP-related damage during HIV infection.

Matrix metalloproteinase inhibitors as therapy for inflammatory and vascular diseases

Matrix metalloproteinases (MMPs) have outgrown the field of extracellular-matrix biology and have progressed towards being important regulatory molecules in cancer and inflammation. This rise in status was accompanied by the development of various classes of inhibitors. Although clinical trials with synthetic inhibitors for the treatment of cancer were disappointing, recent data indicate that the use of selective inhibitors might lead to new therapies for acute and chronic inflammatory and vascular diseases. In this Review, we compare the major classes of MMP inhibitors and advocate that future drug discovery should be based on crucial insights into the differential roles of specific MMPs in pathophysiology obtained with animal models, including knockout studies.

Cerebrospinal fluid and serum levels and intrathecal production of active matrix metalloproteinase-9 (MMP-9) as markers of disease activity in patients with multiple sclerosis

In this study, we employed a sensitive activity assay system to measure cerebrospinal fluid (CSF) and serum levels of active matrix metalloproteinase-9 (MMP-9) in 37 relapsing-remitting (RR), 15 secondary progressive (SP) and nine primary progressive (PP) multiple sclerosis (MS) patients, grouped according to clinical and magnetic resonance imaging (MRI) evidence of disease activity. We also studied, as neurological controls, 48 patients with other inflammatory neurological disorders (OIND) and 48 with non-inflammatory neurological disorders (NIND). To assess active MMP-9/TIMP-1 circuit, CSF and serum levels of MMP-9 tissue inhibitor TIMP-1 were quantified by ELISA in the same patient population. CSF mean levels of active MMP-9, CSF active MMP-9/TIMP-1 ratios and intrathecal active MMP-9 synthesis, as indicated by specific index, were more elevated in MS than in NIND (P < 0.05, < 0.02 and < 0.02, respectively), serum active MMP-9/TIMP-1 ratio was higher in MS (P < 0.01) and OIND (P < 0.02) than in NIND, and serum TIMP-1 concentrations were lower in MS than in NIND (P<0.05). More importantly, serum active MMP-9 mean levels, serum active MMP-9/TIMP-1 ratio and intrathecal production of active MMP-9 were increased in MS patients with clinical (P < 0.001, < 0.001 and < 0.05, respectively) and MRI (P < 0.001, < 0.001 and < 0.02, respectively) disease activity, whereas CSF mean concentrations of active MMP-9 and CSF active MMP-9/TIMP-1 ratio were enhanced only in MS patients with MRI evidence of disease activity (P < 0.02 and < 0.01, respectively). Altogether, these findings suggest that a shift in MMP-9/TIMP-1 balance towards proteolytic activity of MMP-9 could be relevant in MS immune dysregulation. In addition, our results indicate that CSF and serum levels of active MMP-9 may represent a potential surrogate biomarker for monitoring MS disease activity. In particular, serum active MMP-9/TIMP-1 ratio seems to be a very appropriate indicator of ongoing MS inflammation, since it is easily measurable.

LPS-Induced Acute Lung Injury is Attenuated by Phosphodiesterase Inhibition: Effects on Proinflammatory Mediators, Metalloproteinases, NF-??B, and ICAM-1 Expression

BACKGROUND

Acute endotoxemia is characterized by an enhanced inflammatory response. Pentoxifylline (PTX), a phosphodiesterase inhibitor, has been shown to decrease TNF-alpha levels and to down-regulate neutrophil activation, likely because of increases in intracellular cyclic AMP. Its effects on lipopolysaccharide (LPS) induced lung injury, more specifically on tissue neutrophil infiltration and degranulation, adhesion molecule expression, and transcriptional factor activation, have not been fully investigated. We postulated that PTX treatment in acute endotoxemia downregulates the inflammatory response and may decrease lung injury.

METHODS

Male Sprague-Dawley rats were randomized into three groups: Sham (saline i.v.), LPS (5 mg/kg i.v.), and PTX + LPS (25 mg/kg and 5 mg/kg i.v., respectively; concomitant injection). After 4 hours, bronchoalveolar lavage fluid (BAL), plasma, and lungs were sampled. BAL IL-8 (ELISA), BAL MMP-2, plasma MMP-9, and BAL MMP-9 (Zymography) were measured. Lung histology (H&E), in addition to lung MPO, ICAM-1, and NF-kappaB expression evaluated by immunohistochemistry were analyzed. Lung NF-kappaB DNA binding was evaluated by electrophoretic mobility shift assay.

RESULTS

PTX treatment decreased BAL IL-8 levels, BAL MMP-2, and plasma MMP-9 activity. Lung neutrophil infiltration (MPO), ICAM-1 expression and NF-kappaB activation were decreased by PTX. In addition, PTX treatment caused a marked attenuation of LPS-induced lung injury.

CONCLUSIONS

Phosphodiesterase inhibition by PTX attenuates LPS-induced end-organ injury. In addition, proinflammatory cytokine production is also downregulated, likely because of the marked attenuation of NF-kappaB DNA binding and activation.

The potential use of MMP inhibitors to treat CNS diseases

The matrix metalloproteinases (MMPs) are considered to be the physiological mediators of extracellular matrix remodelling. MMPs are involved in a variety of functions and in the nervous system, these include angiogenesis and the extension of neuronal growth cones during development. However, it has become increasingly evident that the aberrant expression of MMPs in the nervous system contributes to diseases that include among others, multiple sclerosis, malignant gliomas, Alzheimer's disease and stroke. This review highlights the evidence that MMPs are involved in diseases of the nervous system, and provides information for the potential beneficial use of MMP inhibitors in NS disorders. However, the application of MMP inhibitors to treat CNS diseases must be balanced carefully against the beneficial roles normally played by MMPs in CNS physiology or recovery.

Interferon-beta inhibits the expression of metalloproteinases in rat glial cell cultures: implications for multiple sclerosis pathogenesis and treatment

Matrix metalloproteinases (MMPs) have been identified as mediators of brain injury in multiple sclerosis (MS) and it has recently been reported that treatment of MS patients with interferon-beta (IFN-beta) reduces MMP-9 serum levels and in vitro release from monocytes. We investigated whether IFN-beta is able to modulate the expression of MMPs in glial cell cultures. Rat microglial and astrocyte cultures were treated with different doses of IFN-beta, then activated by exposure to LPS. In another set of experiments cells were simultaneously activated with LPS and treated with IFN-beta. Culture supernatants collected from astrocytes and microglia were subjected to zymography for the assessment of MMP-2 and MMP-9. Increased amounts of MMP-9 and MMP-2 were observed in supernatants from LPS-treated astrocytes in comparison with supernatants from nontreated control cells. MMP-9 also increased in LPS-treated microglia. The treatment of astrocytes and microglia with IFN-beta inhibited dose-dependently the expression of both MMP-2 and MMP-9 in LPS-treated astrocytes and of MMP-9 in LPS-treated microglia. These results demonstrate a modulating effect of IFN-beta on the release of MMPs from CNS cells. This effect represents an additional mechanism by which IFN-beta, may decrease the development of new CNS lesions in the course of MS.

Functional roles and therapeutic targeting of gelatinase B and chemokines in multiple sclerosis

Multiple sclerosis (MS) is a demyelinating disease of the CNS of unknown cause. Pathogenetic mechanisms, such as chemotaxis, subsequent activation of autoreactive lymphocytes, and skewing of the extracellular proteinase balance, are targets for new therapies. Matrix metalloproteinase gelatinase B (MMP-9) is upregulated in MS and was recently shown to degrade interferon beta, one of the drugs used to treat MS. Consequently, the effect of endogenously produced interferon beta or parenterally given interferon beta may be increased by gelatinase B inhibitors. Blockage of chemotaxis or cell adhesion molecule engagement, and inhibition of hydroxymethyl-glutaryl-coenzyme-A reductase to lower expression of gelatinase B, may become effective treatments of MS, alone or in combination with interferon beta. This may allow interferon beta to be used at lower doses and prevent side-effects.

Approach to discriminate subgroups in multiple sclerosis with cerebrospinal fluid (CSF) basic inflammation indices and TNF-alpha, IL-1beta, IL-6, IL-8

Lumbar CSF and serum pairs of untreated multiple sclerosis patients (MS; n=47) were analyzed on admission. On average, higher CSF leukocyte (lymphocyte and monocyte) counts, IgG index, CSF IgG contents, but not of TNF-alpha, IL-1beta, IL-6, IL-8 in CSF and serum, were revealed in all MS or patients with long disease course (LO-MS) compared with controls. In primary progressive MS (PP-MS) cell counts were low, but IgG contents were high, when compared to relapsing-remitting MS (RR-MS). In clinically probable MS (CP-MS) both contents were low, in clinically definite MS (CD-MS) high. Spearman's correlation with the four monokines and the basic indices in CSF revealed activation patterns known for microglia/macrophages in the four MS subgroups, for astrocytes in CP-MS and RR-MS, for CSF lymphocytes in CP-MS and PP-MS, for cells of blood-brain barrier (BBB) in CP-MS, for intrathecal IgG synthesis in PP-MS and for lymphocyte transfer in CD-MS. Correlations between CSF and serum parameters indicated CNS disease processes to be associated with systemic processes of inflammation (acute, chronic) in CD-MS, RR-MS, and PP-MS in different ways. CSF IgG content, IgG index and systemic markers of inflammation correlated with overall disability scores in LO-MS; increasing levels may indicate a bad outcome.

Chemokines and matrix metalloproteinase-9 in leukocyte recruitment to the central nervous system

Chemokines and matrix metalloproteinases (MMPs) play key roles in leukocyte migration across the blood-brain barrier (BBB) in infectious and inflammatory diseases, including multiple sclerosis (MS). In MS some chemokine receptors are expressed by an increased percentage of T cells in blood, the CSF concentration of chemokine ligands for these receptors is increased, and there is accumulation of T cells expressing relevant chemokine receptors in CSF and in the CNS parenchyma. Chemokine receptor expression patterns appear to reflect disease activity and disease stage in MS. MMPs are constitutively expressed or induced by proinflammatory cytokines and chemokines in leukocytes and CNS-resident cells. Several MMPs are expressed in MS plaques, and the CSF concentration of MMP-9 is increased in MS. The CSF concentration of MMP-9 may reflect disease activity in MS, and the CSF concentration of MMP-9 is higher in patients carrying the MS-associated HLA type DRB1 1501. We review how chemokines and MMP-9 may be involved in the pathogenesis of MS by controlling leukocyte migration between different functional compartments. Measuring expression of these molecules may find use as surrogate markers of disease activity in MS, and interfering with their function holds promise as a novel therapeutic strategy in MS.

A novel rationale for inhibition of gelatinase B in multiple sclerosis: MMP-9 destroys alpha B-crystallin and generates a promiscuous T cell epitope

The small heat shock protein alphaB-crystallin is considered as a candidate autoantigen in multiple sclerosis (MS) lesions. Gelatinase B or matrix metalloproteinase (MMP)-9 is a proteinase establishing various disease-promoting feedback loops in autoimmune diseases. Human alphaB-crystallin was digested with natural gelatinase B and all cleavage sites were identified by a combined approach of mass spectrometry and peptide sequencing analysis. Previously identified immunodominant and cryptic epitopes of alphaB-crystallin in mice and rats were generated and largely left intact by MMP-9 processing. The alphaB-crystallin peptide 1-16, generated as a remnant epitope, provoked a significant T cell response in alphaB-crystallin knockout mice. None of the remnant peptides was encephalitogenic when injected intracerebrally into mice or induced MMP-9 in vitro. Gelatinase B is thus able to release T cell epitopes from intact alphaB-crystallin, but their pathogenic role remains unclear.

Gelatinase B/matrix metalloproteinase-9 cleaves interferon-beta and is a target for immunotherapy

Parenteral administration of interferon (IFN)-beta is one of the currently approved therapies for multiple sclerosis. One characteristic of this disease is the increased production of gelatinase B, also called matrix metalloproteinase (MMP) 9. Gelatinase B is capable of destroying the blood-brain barrier, and of cleaving myelin basic protein into immunodominant and encephalitogenic fragments, thus playing a functional role and being a therapeutic target in multiple sclerosis. Here we demonstrate that gelatinase B proteolytically cleaves IFN-beta, kills its activity, and hence counteracts this cytokine as an antiviral and immunotherapeutic agent. This proteolysis is more pronounced with IFN-beta-1b than with IFN-beta-1a. Furthermore, the tetracycline minocycline, which has a known blocking effect in experimental autoimmune encephalomyelitis, an in vivo model of acute inflammation in multiple sclerosis, and other MMP inhibitors prevent the in vitro degradation of IFN-beta by gelatinase B. These data provide a novel mechanism and rationale for the inhibition of gelatinase B in diseases in which IFN-beta has a beneficial effect. The combination of gelatinase B inhibitors with better and lower pharmacological formulations of IFN-beta may reduce the side-effects of treatment with IFN-beta, and is therefore proposed for multiple sclerosis therapy and the immunotherapy of viral infections.

Serum MMP-2 and MMP-9 are elevated in different multiple sclerosis subtypes

In multiple sclerosis (MS), matrix metalloproteinase (MMP) activity in tissues is the result of a balance between MMPs and their tissue inhibitors (TIMPs). MMP-9 predominates in acute MS lesions and is inhibited by TIMP-1, while MMP-2 may participate in the remodeling of the extracellular matrix (ECM) such as in chronic disease and is inhibited by TIMP-2. These differences may be reflected in serum and cerebrospinal fluid (CSF). We have tried to characterize MMP-2 and MMP-9 activities, in relation to their respective TIMPs, 2 and 1, as a factor of different types of the disease, as this information was not previously clearly stated. We found the MMP-2/TIMP-2 ratio in serum to show higher values in secondary progressive (SP, p=0.02) and primary progressive (PP, p=0.01) MS than short disease duration (SDD) relapsing-remitting (RR) MS, but not different from the healthy control (HC) group. Whereas the MMP-9/TIMP-1 ratio in serum showed higher (p=0.04) values in SDD RR MS than PP but also in active patients, evaluated either clinically (p=0.006) or from the magnetic resonance imaging (MRI, p<0.05), compared to inactive disease. CSF MMP to TIMP ratios did not differ between MS subtypes, suggesting systemic rather CNS-restricted changes. These results show that an increase in MMP-2/TIMP-2 ratio marks chronic progression in MS, but it is as high as in HC, and also confirm that high MMP-9 activity characterizes short duration relapsing and active forms of the disease.

Gelatinase B, PECAM-1 and MCP-3 gene polymorphisms in Belgian multiple sclerosis

Polymorphic microsatellite markers in the genes for gelatinase B, PECAM-1 and MCP-3 have previously been analysed in Swedish and Sardinian individuals to test for association with multiple sclerosis (MS). Confirmation and comparison of genetic associations in various ethnic populations is mandatory and, therefore, we studied these three gene polymorphisms in 216 clinically definite MS patients and 193 normal controls, and in 148 simplex MS families, all of Belgian origin. No allelic associations were found between MS and the CA microsatellite marker in the promoter region of the gelatinase B gene, and the polymorphic CA repeat in the sixth intron of PECAM1. However, the two most abundant alleles of the CA/GA microsatellite polymorphism in the promoter-enhancer region of the MCP-3 gene, A2 (109 bp) and A3 (111 bp), were found to be significantly associated with disease in the case-control study [OR (95% CI)=0.68 (0.51-0.92), p (1 df)=0.015 and OR (95% CI)=1.62 (1.22-2.14), p (1 df)=0.0010, respectively], but not in the family study. These results are in agreement with previous findings in the Swedish and Sardinian populations and reinforce the possibility of a role for chemokines in MS pathogenesis.

Intrathecal synthesis of matrix metalloproteinase-9 in patients with multiple sclerosis: implication for pathogenesis

Matrix metalloproteinase-9 (MMP-9) was detected by zymography and enzyme-linked immunosorbent assay (ELISA) in matched serum and cerebrospinal fluid (CSF) samples from patients with neurological diseases. Patients with relapsing-remitting multiple sclerosis (RR-MS) had serum and CSF MMP-9 levels comparable to those from patients with inflammatory neurological diseases (INDs), but higher than patients with non-inflammatory neurological diseases (NINDs) and healthy donors (HDs). MMP-9 increased in active RR-MS in comparison with inactive RR-MS implying that MMP-9 in MS is related with clinical disease activity. A correlation between the CSF/serum albumin (Q(AIb)) and CSF/serum MMP-9 (Q(MMP-9)) was observed in IND and NIND but not in RR-MS patients, indicating that CSF MMP-9 levels in NIND and IND patents could be influenced by serum MMP-9 and blood-brain barrier (BBB) permeability properties. MS patients had higher values of Q(MMP-9):Q(Alb)(MMP-9 index) than IND and NIND patients suggesting that in MS the increase in CSF MMP-9 could be due to intrathecal synthesis of MMP-9. A significant inverse correlation was found between MMP-9 and its endogenous inhibitor TIMP-1 in RR-MS indicating that in MS patients both the increase in MMP-9 and the decrease in TIMP-1 serum levels could contribute to BBB disruption and T-lymphocyte entry into the CNS.

Activity of matrix metalloproteinase-9 is elevated in sera of patients with systemic lupus erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by the increased production of autoantibodies and by systemic clinical manifestations and damage to multiple organs. The aim of the present study was to analyse matrix metalloproteinase (MMP)-9 activity in sera of patients with active and inactive SLE in order to evaluate its role in the pathogenesis and course of the disease, as well as its diagnostic value. We measured activity levels of MMP-9 and MMP-2, using both gel zymography and activity assay kits, in sera of 40 SLE patients and of 25 healthy controls. We found that MMP-9 activity, but not MMP-2 activity, is significantly elevated in the sera of SLE patients compared with sera samples of healthy controls. High activity levels of MMP-9 were determined in sera of 68% of the SLE patients. Elevated levels of MMP-9 were correlated with the presence of discoid rash, Raynaud phenomenon, pneumonitis, mucosal ulcers and anti-phospholipid antibodies. Changes in activity levels of MMP-9, but not of MMP-2, were observed in sera of the same patient at different periods of the disease course. High levels of MMP-9 did not correlate with disease activity index (SLEDAI, BILAG) in female patients, but correlated with SLE activity in the group of male patients. The results of the present study suggest that MMP-9 plays a role in the pathogenesis of SLE.

Matrix metalloproteinases and tissue inhibitors of metalloproteinases in cerebrospinal fluid differ in multiple sclerosis and Devic's neuromyelitis optica

Matrix metalloproteinases (MMPs) are increased in the CSF of patients with multiple sclerosis. Devic's neuromyelitis optica (DNO) is a demyelinating syndrome that involves the optic nerve and cervical cord but differs pathologically from multiple sclerosis. Therefore, we hypothesized that the type of inflammatory reaction that causes MMPs to be elevated in multiple sclerosis would be absent in patients with DNO. CSF was collected from 23 patients with relapsing-remitting or secondary progressive multiple sclerosis, all of whom were experiencing acute symptoms, from seven patients with DNO, and from seven normal volunteers. Diagnoses were made according to current criteria on the basis of clinical manifestations, imaging results and CSF studies. IgG synthesis was increased in the CSF of multiple sclerosis patients but not in that of DNO patients. Zymography, reverse zymography and ELISA (enzyme-linked immunosorbent assay) were used to measure gelatinase A (MMP-2), gelatinase B (MMP-9) and tissue inhibitors of metalloproteinases (TIMPs). Zymograms showed that multiple sclerosis patients had elevated MMP-9 compared with DNO patients and controls (P: < 0.05). TIMP-1 and TIMP-2 levels were similar in all three groups. We conclude that multiple sclerosis patients have higher MMP-9 levels in the CSF than patients with DNO, which supports the different pathological mechanisms of these diseases.

Matrix metalloproteinase-9 (MMP-9) in human cerebrospinal fluid (CSF): elevated levels are primarily related to CSF cell count

Matrix metalloproteinase-9 (MMP-9) was investigated by enzyme-linked immunosorbent assay (ELISA) and zymography in 111 paired CSF and serum samples from patients with various neurological disorders. In 20 patients with blood-brain barrier (BBB) impairment but normal CSF cell count, elevated levels of MMP-9 were not observed by ELISA measurement. Another 11 patients characterized in the same way, exhibited only slightly increased MMP-9 levels. In contrast, in 12 patients with intact BBB but elevated CSF cell count, MMP-9 was increased too. It was shown by the more sensitive zymography that MMP-9 increased if CSF cell count exceeded five cells per microl. Spearman rank statistics revealed that MMP-9 concentration in CSF correlated with CSF cell count (r=0.755; P<0.0001), but not with CSF/serum albumin ratio (Q(Alb)) (r=0.212; P=0.057), a measure for BBB impairment. Moreover, the CSF/serum MMP-9 ratio (Q(MMP-9)) did not correlate with Q(Alb)(r=0.192; P=0.100). By use of a Boyden chamber, in which granulocytes migrated through a reconstituted basement membrane, it was demonstrated that the MMP-9 concentration in the lower chamber correlated very significantly with the number of accumulated cells (r(2)=0.7692; P<0.0001). The meaning of the increase of MMP-9 in CSF is critically discussed.

Polymorphism analysis suggests that the gelatinase B gene is not a susceptibility factor for multiple sclerosis

The human gelatinase B (MMP-9) gene promoter region contains a CA microsatellite repeat and a single nucleotide polymorphism which are known to influence transcriptional activity. These two polymorphisms were used to investigate the existence of an association between multiple sclerosis (MS) susceptibility and the MMP-9 gene. In a case-control analysis of 345 Swedish individuals and in a study of 125 Sardinian simplex families no genetic associations between the gelatinase B gene polymorphisms and MS susceptibility were found. These data reinforce the suggestion of epistasis in the regulation of the metalloproteinase-inhibitor balance in MS.

Preferential expression of myelencephalon-specific protease by oligodendrocytes of the adult rat spinal cord white matter

Myelencephalon-specific protease (MSP) is a novel serine protease that is expressed predominantly in the nervous system. In the adult rat spinal cord, MSP mRNA expression was dramatically upregulated, in both the white and gray matter, after systemic exposure to the glutamate receptor agonist, kainic acid (KA) (Scarisbrick et al. J Neurosci 17: 8156-8168, 1997b). To determine the cell-specific expression patterns of MSP, we generated MSP-specific monoclonal antibodies. These have been used in immunohistochemical and in situ hybridization colocalization studies, to demonstrate that MSP mRNA and protein are produced predominantly by CNP-immunoreactive oligodendroglia, but not by GFAP-immunoreactive astrocytes, in the white matter of the normal adult cord. In vitro, the soma of oligodendrocytes were also densely MSP immunoreactive, as were their growth tips, while astrocytes were associated with lower levels. These findings suggest that the enzymatic activity of MSP is likely to be important in the biology of oligodendrocytes and/or in the maintenance of the nerve fiber tracts of the adult spinal cord.

HLA DRB1*1501 and intrathecal inflammation in multiple sclerosis

CD4 T cells are considered to be pivotal in the pathogenesis of multiple sclerosis (MS), and the human leukocyte antigen (HLA) haplotype associated with DRB1*1501 confers susceptibility to MS in patients of Northern European descent. Some previous studies have suggested an association of DRB1*1501 with T- and B-cell reactivity to specific myelin protein peptides, other studies suggested an association with enhanced cytokine production or intrathecal immunoglobulin (Ig) synthesis. In order to further assess the role of DRB1*1501 in the pathogenesis of MS, we studied intrathecal inflammation and T-cell phenotypes in patients with possible onset symptoms or clinically definite MS. Presence of DRB1*1501 was associated with higher levels of cerebrospinal fluid (CSF) inflammation as assessed by IgG synthesis levels and higher levels of matrix metalloproteinase-9 activity. DRB1*1501-positive patients also had a lower percentage of T cells in CSF expressing HLA-DR without co-expressing CD25. These findings suggest that enhanced intrathecal inflammation and an altered T-cell activation status may be of importance in conferring the DRB1*1501-associated susceptibility to MS.

CCR5 delta32, matrix metalloproteinase-9 and disease activity in multiple sclerosis

Chemokines and matrix metalloproteinases (MMPs) appear to be crucial in leukocyte recruitment to the central nervous system in multiple sclerosis (MS). CCR5 delta32, a truncated allele of the CC chemokine receptor CCR5 gene encoding a non-functional receptor, did not confer protection from MS. CCR5 delta32 was, however, associated with a lower risk of recurrent clinical disease activity. High CSF levels of MMP-9 activity were also associated with recurrent disease activity. These results directly link intrathecal inflammation to disease activity in patients with MS, suggesting that treatments targeting CCR5 or treatment with MMP inhibitors may attenuate disease activity in MS.

Resistance of young gelatinase B-deficient mice to experimental autoimmune encephalomyelitis and necrotizing tail lesions

Regulated expression of matrix metalloproteinases (MMPs) and their inhibitors (TIMPs) plays a role in various physiological processes. To determine in vivo how unbalanced expression of these factors can promote or affect the course of pathologies, we knocked out the mouse gelatinase B gene by replacing the catalytic and zinc-binding domains with an antisense-oriented neomycin resistance gene. Adult gelatinase B-deficient mice and wild-type controls could be induced to develop experimental autoimmune encephalomyelitis (EAE) with similar scores for neurologic disease, blood-brain barrier permeability, and central nervous system histopathology. However, whereas diseased control animals showed necrotizing tail lesions with hyperplasia of osteocartilaginous tissue, adult gelatinase B-deficient mice were resistant to this tail pathology. Gelatinase B-deficient mice younger than 4 weeks of age were significantly less susceptible to the development of EAE than were age matched controls and, even as they aged, they remained resistant to tail lesions. These data illustrate that gelatinase B expression plays a role in the development of the immune system and that, in ontogenesis, the propensity to develop autoimmunity is altered by the absence of this MMP.

Serum gelatinase B, TIMP-1 and TIMP-2 levels in multiple sclerosis. A longitudinal clinical and MRI study

Metalloproteinases have been implicated in the pathogenesis of multiple sclerosis. We report longitudinal serum levels of gelatinase B and of the tissue inhibitors of matrix metalloproteinases (TIMP), TIMP-1 and TIMP-2, in 21 patients with relapsing multiple sclerosis. Patients had monthly clinical and gadolinium-enhanced MRI follow-up for 10 months. Longitudinal samples in nine healthy controls and cross-sectional samples from 12 patients with inflammatory CNS disease and 15 patients with other neurological diseases were used for comparison. Average serum gelatinase B, TIMP-1 and TIMP-2 levels were significantly higher in multiple sclerosis patients and those with other neurological diseases than in healthy controls. In the patients with multiple sclerosis, gelatinase B levels were significantly higher during clinical relapse compared with periods of clinical stability. Multiple sclerosis patients with high mean serum gelatinase B levels had significantly more T1-weighted gadolinium-enhancing MRI lesions than those with mean levels within the control range. TIMP-1 levels were not different during relapse and between relapses. There was a trend for TIMP-2 levels to be lower during relapse compared with non-relapse periods. For similar levels of serum gelatinase B, associated TIMP-1 levels were significantly lower and TIMP-2 levels significantly higher in multiple sclerosis patients compared with the inflammatory CNS control group. We propose that an abnormality in the inhibitory response to metalloproteinases may play an aetiological role in the chronicity of multiple sclerosis.