Elevation of matrix metalloproteinases (MMPs) in multiple sclerosis and impact of immunomodulators

Biological significance and pathophysiological role of Matrix Metalloproteinases in the Central Nervous System

Matrix Metalloproteinases (MMPs), which are endopeptidase reliant on zinc, are low in embryonic tissues but increases in response to a variety of physiological stimulus and pathological stresses. Neuro-glial cells, endothelial cells, fibroblasts, and leucocytes secrete MMPs, which cleave extracellular matrix proteins in a time-dependent manner. MMPs affect synaptic plasticity and the development of short-term memory by controlling the size, shape, and excitatory synapses' function through the lateral diffusion of receptors. In addition, MMPs influence the Extracellular Matrix proteins in the Peri-Neuronal Net at the Neuro-glial interface, which aids in the establishment of long-term memory. Through modulating neuronal, and glial cells migration, differentiation, Neurogenesis, and survival, MMPs impact brain development in mammals. In adult brains, MMPs play a beneficial role in physiological plasticity, which includes learning, memory consolidation, social interaction, and complex behaviors, by proteolytically altering a wide variety of factors, including growth factors, cytokines, receptors, DNA repair enzymes, and matrix proteins. Additionally, stress, depression, addiction, hepatic encephalopathy, and stroke may all have negative effects on MMPs. In addition to their role in glioblastoma development, MMPs influence neurological diseases such as epilepsy, schizophrenia, autism spectrum disorder, brain damage, pain, neurodegeneration, and Alzheimer's and Parkinson's. To help shed light on the potential of MMPs as a therapeutic target for neurodegenerative diseases, this review summarizes their regulation, mode of action, and participation in brain physiological plasticity and pathological damage. Finally, by employing different MMP-based nanotools and inhibitors, MMPs may also be utilized to map the anatomical and functional connectome of the brain, analyze its secretome, and treat neurodegenerative illnesses.

Blood-brain barrier dysfunction and decreased transcription of tight junction proteins in epileptic dogs

BACKGROUND

Epilepsy in dogs and humans is associated with blood-brain barrier (BBB) dysfunction (BBBD), which may involve dysfunction of tight junction (TJ) proteins, matrix metalloproteases, and astrocytes. Imaging techniques to assess BBB integrity, to identify potential treatment strategies, have not yet been evaluated in veterinary medicine.

HYPOTHESIS

Some dogs with idiopathic epilepsy (IE) will exhibit BBBD. Identifying BBBD may improve antiepileptic treatment in the future.

ANIMALS

Twenty-seven dogs with IE and 10 healthy controls.

METHODS

Retrospective, prospective cohort study. Blood-brain barrier permeability (BBBP) scores were calculated for the whole brain and piriform lobe of all dogs by using dynamic contrast enhancement (DCE) magnetic resonance imaging (MRI) and subtraction enhancement analysis (SEA). Matrix metalloproteinase-9 (MMP9) activity in serum and cerebrospinal fluid (CSF) was measured and its expression in the piriform lobe was examined using immunofluorescent staining. Gene expression of TJ proteins and astrocytic transporters was analyzed in the piriform lobe.

RESULTS

The DCE-MRI analysis of the piriform lobe identified higher BBBP score in the IE group when compared with controls (34.5% vs 26.5%; P = .02). Activity and expression of MMP9 were increased in the serum, CSF, and piriform lobe of IE dogs as compared with controls. Gene expression of Kir4.1 and claudin-5 in the piriform lobe of IE dogs was significantly lower than in control dogs.

CONCLUSIONS AND CLINICAL IMPORTANCE

Our findings demonstrate BBBD in dogs with IE and were supported by increased MMP9 activity and downregulation of astrocytic potassium channels and some TJ proteins. Blood brain barrier dysfunction may be a novel antiepileptic therapy target.

Whole-Body Cryostimulation in Multiple Sclerosis: A Scoping Review

Multiple sclerosis (MS) is the most common cause of non-traumatic long-term disability in young adults. Whole-body cryostimulation (WBC) is a cold-based physical therapy known to induce physiological exercise-mimicking changes in the cardiovascular, neuromuscular, immune, and endocrine systems and to influence functional and psychological parameters by exposing the human body to cryogenic temperatures (≤-110 °C) for 2-3 min. The purpose of this scoping review is to present an overall view on the potential role of WBC as an adjuvant therapy in the treatment of MS. PubMed, ScienceDirect, Embase, and Web of Science were searched up to 30 November 2023, and a total of 13 articles were included. WBC may have beneficial antioxidant effects as a short-term adjuvant treatment in MS. There were no significant changes in antioxidant enzymes, nitric oxide levels, metalloproteinase levels, blood counts, rheology, and biochemistry. WBC can lead to a reduction in fatigue and an improvement in functional status, with a significant effect on both mental and physical well-being. There were no reported adverse effects. The results suggest that WBC may complement therapeutic options for patients with MS, as the effects of cryogenic cold stimulation have been shown to activate antioxidant processes and improve functional status, mood, anxiety, and fatigue.

Pathogenic Role of Fibrinogen in the Neuropathology of Multiple Sclerosis: A Tale of Sorrows and Fears

Multiple sclerosis (MS) is an autoimmune demyelinating neurodegenerative disease of the central nervous system (CNS) due to injury of the myelin sheath by immune cells. The clotting factor fibrinogen is involved in the pathogenesis of MS by triggering microglia and the progress of neuroinflammation. Fibrinogen level is correlated with MS severity; consequently, inhibition of the fibrinogen cascade may reduce MS neuropathology. Thus, this review aimed to clarify the potential role of fibrinogen in the pathogenesis of MS and how targeting of fibrinogen affects MS neuropathology. Accumulation of fibrinogen in the CNS may occur independently or due to disruption of blood-brain barrier (BBB) integrity in MS. Fibrinogen acts as transduction and increases microglia activation which induces the progression of inflammation, oxidative stress, and neuronal injury. Besides, brain fibrinogen impairs the remyelination process by inhibiting the differentiation of oligodendrocyte precursor cells. These findings proposed that fibrinogen is associated with MS neuropathology through interruption of BBB integrity, induction of neuroinflammation, and demyelination with inhibition of the remyelination process by suppressing oligodendrocytes. Therefore, targeting of fibrinogen and/or CD11b/CD18 receptors by metformin and statins might decrease MS neuropathology. In conclusion, inhibiting the expression of CD11b/CD18 receptors by metformin and statins may decrease the pro-inflammatory effect of fibrinogen on microglia which is involved in the progression of MS.

Effect of Whole-Body Cryotherapy on Oxidant-Antioxidant Imbalance in Women with Multiple Sclerosis

The aim of the study was to investigate whether 20 whole-body cryotherapy treatments have an effect on oxidative-antioxidant imbalances in women with multiple sclerosis. Fifty women aged 30-55 were examined: study group-15 women with multiple sclerosis, subjected to whole-body cryotherapy; first control group-20 women with multiple sclerosis who did not receive cryotherapy intervention; second control group-15 healthy women who participated in cryotherapy treatments. Blood from the examined women was collected twice (before and after the series of 20 cryotherapy sessions). An insignificant increase in the total antioxidant capacity (study group: p = 0.706; second control group: p = 0.602) was observed after the whole-body cryotherapy intervention. After the series of cryotherapy sessions, the total oxidative status/total oxidative capacity value was insignificantly decreased among the multiple sclerosis patients (decrease by 14.03%, p = 0.495). In women with multiple sclerosis, no significant cryotherapy impact was demonstrated on changes in the oxidant-antioxidant imbalance or concentrations of nitric oxide, uric acid, or matrix metalloproteinase-9.

Association of the matrix metalloproteinases (MMPs) family gene polymorphisms and the risk of coronavirus disease 2019 (COVID-19); implications of contribution for development of neurological symptoms in the COVID-19 patients

BACKGROUND

Seemingly, the Matrix metalloproteinases (MMPs) play a role in the etiopathogenesis of coronavirus disease 2019 (COVID-19). Here in this study, we determined the association of MMP9 rs3918242, MMP3 rs3025058, and MMP2 rs243865 polymorphisms with the risk of COVID-19, especially in those with neurological syndrome (NS).

METHODS

We enrolled 500 patients with COVID-19 and 500 healthy individuals. To genotype the target SNPs, the Real-time allelic discrimination technique was used. To determine serum levels of MMPs, Enzyme-linked immunosorbent assay (ELISA) was exerted.

RESULTS

The MMP9 gene rs3918242 and MMP3 gene rs3025058 SNP were significantly associated with increased COVID-19 risk and susceptibility to COVID-19 with NS. The serum level of MMP-9 and MMP-3 was significantly higher in COVID-19 cases compared with the healthy controls. Serum MMP-9 and MMP-3 levels were also higher in COVID-19 subjects with NS in comparison to the healthy controls. The polymorphisms in MMP genes were not associated with serum level of MMPs.

CONCLUSION

MMP9 and MMP3 gene polymorphisms increases the susceptibility to COVID-19 as well as COVID-19 with neurologic syndrome, but they probably have no role in the regulation of serum MMP-9 and MMP-3 levels.

Intrinsic blood-brain barrier dysfunction contributes to multiple sclerosis pathogenesis

Blood-brain barrier (BBB) breakdown and immune cell infiltration into the CNS are early hallmarks of multiple sclerosis (MS). The mechanisms leading to BBB dysfunction are incompletely understood and generally thought to be a consequence of neuroinflammation. Here, we have challenged this view and asked if intrinsic alterations in the BBB of MS patients contribute to MS pathogenesis. To this end, we made use of human induced pluripotent stem cells derived from healthy controls and MS patients and differentiated them into brain microvascular endothelial cell (BMEC)-like cells as in vitro model of the BBB. MS-derived BMEC-like cells showed impaired junctional integrity, barrier properties and efflux pump activity when compared to healthy controls. Also, MS-derived BMEC-like cells displayed an inflammatory phenotype with increased adhesion molecule expression and immune cell interactions. Activation of Wnt/β-catenin signalling in MS-derived endothelial progenitor cells enhanced barrier characteristics and reduced the inflammatory phenotype. Our study provides evidence for an intrinsic impairment of BBB function in MS patients that can be modelled in vitro. Human iPSC-derived BMEC-like cells are thus suitable to explore the molecular underpinnings of BBB dysfunction in MS and will assist in the identification of potential novel therapeutic targets for BBB stabilization.

Metalloproteinases and Tissue Inhibitors in Generalized Myasthenia Gravis. A Preliminary Study

INTRODUCTION

Matrix metalloproteinases (MMPs) and tissue inhibitors of metalloproteinases (TIMPs) have recently been proposed as promising biomarkers in different immune-mediated disorders. We evaluated the plasma levels of MMP-9 and MMP-2 and their tissue inhibitors TIMP-1 and TIMP-2 in a patients' cohort with generalized myasthenia gravis (MG).

METHODS

Plasma concentrations of MMP-9, MMP-2, TIMP-1 and TIMP-2 were evaluated in 14 patients with generalized MG and 13 age- and sex-matched healthy controls. The severity of disease was assessed by the modified Osserman classification.

RESULTS

Compared to the healthy subjects, MG patients had increased plasma concentrations of MMP-9, but reduced plasma levels of MMP-2 and TIMP-1. MG patients also showed a positive correlation between MMP-2 concentrations and disease severity. An increase in MMP-9 levels and MMP-9/TIMP-1 ratio and a decrease in MMP-2 levels and MMP-2/TIMP-2 ratio were detected in patients with generalized MG. Higher levels of MMP-2 correlated with greater disease severity.

DISCUSSION

Our preliminary findings suggest that MMPs and TIMPs could play a role in the pathogenesis of MG and might be associated with the risk of clinical deterioration.

A Scoping Review on Body Fluid Biomarkers for Prognosis and Disease Activity in Patients with Multiple Sclerosis

Multiple sclerosis (MS) is a complex demyelinating disease of the central nervous system, presenting with different clinical forms, including clinically isolated syndrome (CIS), which is a first clinical episode suggestive of demyelination. Several molecules have been proposed as prognostic biomarkers in MS. We aimed to perform a scoping review of the potential use of prognostic biomarkers in MS clinical practice. We searched MEDLINE up to 25 November 2021 for review articles assessing body fluid biomarkers for prognostic purposes, including any type of biomarkers, cell types and tissues. Original articles were obtained to confirm and detail the data reported by the review authors. We evaluated the reliability of the biomarkers based on the sample size used by various studies. Fifty-two review articles were included. We identified 110 molecules proposed as prognostic biomarkers. Only six studies had an adequate sample size to explore the risk of conversion from CIS to MS. These confirm the role of oligoclonal bands, immunoglobulin free light chain and chitinase CHI3L1 in CSF and of serum vitamin D in the prediction of conversion from CIS to clinically definite MS. Other prognostic markers are not yet explored in adequately powered samples. Serum and CSF levels of neurofilaments represent a promising biomarker.

Minocycline treatment in clinically isolated syndrome and serum NfL, GFAP, and metalloproteinase levels

Background:

In the trial of Minocycline in Clinically Isolated Syndrome (MinoCIS), minocycline significantly reduced the risk of conversion to clinically definite multiple sclerosis (CDMS). Neurofilament light chain (NfL) and glial fibrillary acidic protein (GFAP) are emerging biomarkers in MS, and minocycline modulates matrix metalloproteinases (MMPs).

Objective:

To assess the value of blood NfL and GFAP as a biomarker of baseline and future disease activity and its utility to monitor treatment response in minocycline-treated patients with clinically isolated syndrome (CIS).

Methods:

We measured NfL, GFAP, and MMPs in blood samples from 96 patients with CIS from the MinoCIS study and compared biomarkers with clinical and radiologic characteristics and outcome.

Results:

At baseline, NfL levels correlated with T₂ lesion load and number of gadolinium-enhancing lesions. Baseline NfL levels predicted conversion into CDMS at month 6. GFAP levels at baseline were correlated with T₂ lesion volume. Minocycline treatment significantly increased NfL levels at 3 months but not at 6 months, and decreased GFAP levels at month 6. Minocycline decreased MMP-7 concentrations at month 1.

Discussion:

Blood NfL levels are associated with measures of disease activity in CIS and have prognostic value. Minocycline increased NfL levels at month 3, but reduced GFAP and MMP-7 levels.

Ameliorating potential of curcumin and its analogue in central nervous system disorders and related conditions: A review of molecular pathways

Curcumin, isolated from turmeric (Curcuma longa L.) is one of the broadly studied phytomolecule owing to its strong antioxidant and anti-inflammatory potential and has been considered a promising therapeutic candidate in a wide range of disorders. Considering, its low bioavailability, different curcumin analogs have been developed to afford desired pharmacokinetic profile and therapeutic outcome in varied pathological states. Several preclinical and clinical studies have indicated that curcumin ameliorates mitochondrial dysfunction, inflammation, oxidative stress apoptosis-mediated neural cell degeneration and could effectively be utilized in the treatment of different neurodegenerative diseases. Hence, in this review, we have summarized key findings of experimental and clinical studies conducted on curcumin and its analogues with special emphasis on molecular pathways, viz. NF-kB, Nrf2-ARE, glial activation, apoptosis, angiogenesis, SOCS/JAK/STAT, PI3K/Akt, ERK1/2 /MyD88 /p38 MAPK, JNK, iNOS/NO, and MMP pathways involved in imparting ameliorative effects in the therapy of neurodegenerative disorders and associated conditions.

Matrix metalloproteinases and tissue inhibitors of metalloproteinases in murine β-coronavirus-induced neuroinflammation

Mouse hepatitis virus (MHV; m-β-CoV) serves as a useful model for studying the cellular factors involved in neuroinflammation. To understand the role of matrix metalloproteinases (MMPs) in neuroinflammation, brain tissues from m-β-CoV-infected mice were harvested at different days post-infection (d.p.i) and investigated for Mmp expression by RT-qPCR. Mmp-2, -3, -8, -12 showed significant mRNA upregulation peaking with viral replication between 5 and 6 d.p.i. Elevated levels of MMP regulator TIMP-1 are suggestive of a TIMP-1 mediated host antiviral response. Biological network assessment suggested a direct involvement of MMP-3, -8, -14 in facilitating peripheral leukocyte infiltrations. Flow cytometry confirmed the increased presence of NK cells, CD4⁺ and CD8⁺ T cells, neutrophils, and MHCII expressing cells in the m-β-CoV infected mice brain. Our study revealed that m-β-CoV upregulated Park7, RelA, Nrf2, and Hmox1 transcripts involved in ROS production and antioxidant pathways, describing the possible nexus between oxidative pathways, MMPs, and TIMP in m-β-CoV-induced neuroinflammation.

Brain Barriers and Multiple Sclerosis: Novel Treatment Approaches from a Brain Barriers Perspective

Multiple sclerosis (MS) is considered a prototypic organ specific autoimmune disease targeting the central nervous system (CNS). Blood-brain barrier (BBB) breakdown and enhanced immune cell infiltration into the CNS parenchyma are early hallmarks of CNS lesion formation. Therapeutic targeting of immune cell trafficking across the BBB has proven a successful therapy for the treatment of MS, but comes with side effects and is no longer effective once patients have entered the progressive phase of the disease. Beyond the endothelial BBB, epithelial and glial brain barriers establish compartments in the CNS that differ in their accessibility to the immune system. There is increasing evidence that brain barrier abnormalities persist during the progressive stages of MS. Here, we summarize the role of endothelial, epithelial, and glial brain barriers in maintaining CNS immune privilege and our current knowledge on how impairment of these barriers contributes to MS pathogenesis. We discuss how therapeutic stabilization of brain barriers integrity may improve the safety of current therapeutic regimes for treating MS. This may also allow for the development of entirely novel therapeutic approaches aiming to restore brain barriers integrity and thus CNS homeostasis, which may be specifically beneficial for the treatment of progressive MS.

MMP-9 as a Biomarker for Predicting Hemorrhagic Strokes in Moyamoya Disease

Objective: This study was conducted in order to investigate the association of matrix metalloproteinase (MMP)-9 levels with phenotypes of moyamoya disease (MMD).

Methods: This study included plasma samples from 84 MMD patients. The clinical variables of these patients were reviewed from the medical record. The serum concentration of tight junction, adherens junction proteins, and MMPs (MMP-2 and MMP-9) was determined using the ELISA method. Patients with hemorrhagic-onset MMD were compared with those with ischemic-onset MMD.

Results: Compared with pediatric patients, the expression of MMP-9 was significantly higher, while the MMP-2 and vascular endothelial-cadherin were lower in adult patients. In adult subgroup analysis, hemorrhagic MMD patients exhibited significantly higher serum concentrations of MMP-9 compared with ischemic MMD patients. The ROC curve identified that a baseline serum MMP-9 level >1,011 ng/ml may be associated with spontaneous hemorrhage in adult MMD patients with 70.37% sensitivity and 71.88% specificity [area under curve (AUC), 0.73; 95% CI 0.597–0.864; P = 0.003]. A late Suzuki stage (>4) (OR 4.565, 95% CI 1.028–20.280, P = 0.046) and serum concentrations of MMP-9 >1,011 ng/ml (OR 7.218, 95% CI 1.826–28.533, P = 0.005) are risk predictors of hemorrhages in MMD patients. Hemorrhagic-type MMD patients had higher serum levels of MMP-9 and BBB permeability compared with ischemic-type MMD patients. Adult MMD patients had higher serum levels of MMP-9 and BBB permeability compared with pediatric patients.

Conclusions: MMP-9 might serve as a biomarker for hemorrhage prediction in MMD. Serum MMP-9 level >1,011 ng/ml is an independent risk factor of MMD hemorrhagic strokes.

Multimodal peripheral fluid biomarker analysis in clinically isolated syndrome and early multiple sclerosis

BACKGROUND

Increasing evidence suggests that various inflammatory, immunological and metabolic pathways are altered in the clinically isolated syndrome (CIS) of multiple sclerosis (MS). Moreover, recent diagnostic criteria have made possible the very early diagnosis of MS. We evaluated multiple fluid biomarkers in people with early MS and CIS.

METHODS

We measured blood levels of cytokines, matrix metalloproteinases (MMPs), serum metabolomics and immune cell immunophenotyping in participants in the Trial of Minocycline in a Clinically Isolated Syndrome of Multiple Sclerosis.

RESULTS

When compared with healthy controls, people with early MS/CIS had higher levels of eotaxin, MCP-3, IL-1 receptor antagonist, IL-1β, IL-9 and IP-10, as well as MMPs 1, 8 and 9. In metabolomics analysis, the alanine, aspartate and glutamate metabolism and the synthesis and degradation of ketone bodies pathways were altered compared to healthy controls. There were no differences in lymphocyte subpopulation numbers. Out of all these biomarkers, only MMP-1 was able to differentiate between early MS and CIS, and was found to correlate with lesion volume and gadolinium enhancing lesions on MRI.

CONCLUSION

The immunological and metabolic profile of CIS and early MS is remarkably similar, supporting that these are a continuum of a common underlying pathophysiological process.

Multifaceted Role of Matrix Metalloproteinases in Neurodegenerative Diseases: Pathophysiological and Therapeutic Perspectives

Neurodegeneration is the pathological condition, in which the nervous system or neuron loses its structure, function, or both, leading to progressive degeneration or the death of neurons, and well-defined associations of tissue system, resulting in clinical manifestations. Neuroinflammation has been shown to precede neurodegeneration in several neurodegenerative diseases (NDs). No drug is yet known to delay or treat neurodegeneration. Although the etiology and potential causes of NDs remain widely indefinable, matrix metalloproteinases (MMPs) evidently have a crucial role in the progression of NDs. MMPs, a protein family of zinc (Zn²⁺)-containing endopeptidases, are pivotal agents that are involved in various biological and pathological processes in the central nervous system (CNS). The current review delineates the several emerging evidence demonstrating the effects of MMPs in the progression of NDs, wherein they regulate several processes, such as (neuro)inflammation, microglial activation, amyloid peptide degradation, blood brain barrier (BBB) disruption, dopaminergic apoptosis, and α-synuclein modulation, leading to neurotoxicity and neuron death. Published papers to date were searched via PubMed, MEDLINE, etc., while using selective keywords highlighted in our manuscript. We also aim to shed a light on pathophysiological effect of MMPs in the CNS and focus our attention on its detrimental and beneficial effects in NDs, with a special focus on Parkinson's disease (PD), amyotrophic lateral sclerosis (ALS), Alzheimer's disease (AD), multiple sclerosis (MS), and Huntington's disease (HD), and discussed various therapeutic strategies targeting MMPs, which could serve as potential modulators in NDs. Over time, several agents have been developed in order to overcome challenges and open up the possibilities for making selective modulators of MMPs to decipher the multifaceted functions of MMPs in NDs. There is still a greater need to explore them in clinics.

Metal Imbalance in Neurodegenerative Diseases with a Specific Concern to the Brain of Multiple Sclerosis Patients

There is increasing evidence that deregulation of metals contributes to a vast range of neurodegenerative diseases including multiple sclerosis (MS). MS is a chronic inflammatory disease of the central nervous system (CNS) manifesting disability and neurological symptoms. The precise origin of MS is unknown, but the disease is characterized by focal inflammatory lesions in the CNS associated with an autoimmune reaction against myelin. The treatment of this disease has mainly been based on the prescription of immunosuppressive and immune-modulating agents. However, the rate of progressive disability and early mortality is still worrisome. Metals may represent new diagnostic and predictive markers of severity and disability as well as innovative candidate drug targets for future therapies. In this review, we describe the recent advances in our understanding on the role of metals in brain disorders of neurodegenerative diseases and MS patients.

Minocycline for the management of multiple sclerosis: repositioning potential, opportunities, and challenges

INTRODUCTION

Multiple sclerosis (MS) is a chronic demyelinating inflammatory disorder with variable clinical and pathologic characteristics reflecting multiple underlying pathophysiologic mechanisms. Repositioning of existing drugs for the new indications offers several advantages including significant reduction in the cost and time of drug development and exemption from early phase clinical trials. Minocycline has been reported to exhibit immunomodulation in several pre-clinical and clinical studies through suppression of migratory inflammatory cells, modulation of peripheral immune response, and inhibition of microglial activation within the CNS.

AREAS COVERED

Here, the authors review the repositioning potential of minocycline for the treatment of MS along with appraisal of the evidence obtained from preclinical and clinical research. The authors also discuss the advantages and potential safety concerns related to the use of minocycline for the management of MS.

EXPERT OPINION

Minocycline offers several distinct advantages in terms of well-known safety profile, lower cost of therapy, widespread availability, and being available as an oral formulation. The authors call upon the public and private funders to facilitate well designed and adequately powered randomized clinical trials that can provide conclusive evidence regarding the safety and efficacy of minocycline in patients with MS.

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.

Towards a comprehensive etiopathogenetic and pathophysiological theory of multiple sclerosis

Background: Multiple sclerosis (MS) is a neurodegenerative disease caused by dysfunction of the immune system that affects the central nervous system (CNS). It is characterized by demyelination, chronic inflammation, neuronal and oligodendrocyte loss and reactive astrogliosis. It can result in physical disability and acute neurological and cognitive problems. Despite the gains in knowledge of immunology, cell biology, and genetics in the last five decades, the ultimate etiology or specific elements that trigger MS remain unknown. The objective of this review is to propose a theoretical basis for MS etiopathogenesis.Methods: Search was done by accessing PubMed/Medline, EBSCO, and PsycINFO databases. The search string used was "(multiple sclerosis* OR EAE) AND (pathophysiology* OR etiopathogenesis)". The electronic databases were searched for titles or abstracts containing these terms in all published articles between January 1, 1960, and June 30, 2019. The search was filtered down to 362 articles which were included in this review.Results: A framework to better understand the etiopathogenesis and pathophysiology of MS can be derived from four essential factors; mitochondria dysfunction (MtD) & oxidative stress (OS), vitamin D (VD), sex hormones and thyroid hormones. These factors play a direct role in MS etiopathogenesis and have a modulatory effect on many other factors involved in the disease.Conclusions: For better MS prevention and treatment outcomes, efforts should be geared towards treating thyroid problems, sex hormone alterations, VD deficiency, sleep problems and melatonin alterations. MS patients should be encouraged to engage in activities that boost total antioxidant capacity (TAC) including diet and regular exercise and discouraged from activities that promote OS including smoking and alcohol consumption.

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.

NGL-3 in the regulation of brain development, Akt/GSK3b signaling, long-term depression, and locomotive and cognitive behaviors

Netrin-G ligand-3 (NGL-3) is a postsynaptic adhesion molecule known to directly interact with the excitatory postsynaptic scaffolding protein postsynaptic density-95 (PSD-95) and trans-synaptically with leukocyte common antigen-related (LAR) family receptor tyrosine phosphatases to regulate presynaptic differentiation. Although NGL-3 has been implicated in the regulation of excitatory synapse development by in vitro studies, whether it regulates synapse development or function, or any other features of brain development and function, is not known. Here, we report that mice lacking NGL-3 (Ngl3^−/− mice) show markedly suppressed normal brain development and postnatal survival and growth. A change of the genetic background of mice from pure to hybrid minimized these developmental effects but modestly suppressed N-methyl-D-aspartate (NMDA) receptor (NMDAR)-mediated synaptic transmission in the hippocampus without affecting synapse development, α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor (AMPAR)-mediated basal transmission, and presynaptic release. Intriguingly, long-term depression (LTD) was near-completely abolished in Ngl3^−/− mice, and the Akt/glycogen synthase kinase 3β (GSK3β) signaling pathway, known to suppress LTD, was abnormally enhanced. In addition, pharmacological inhibition of Akt, but not activation of NMDARs, normalized the suppressed LTD in Ngl3^−/− mice, suggesting that Akt hyperactivity suppresses LTD. Ngl3^−/− mice displayed several behavioral abnormalities, including hyperactivity, anxiolytic-like behavior, impaired spatial memory, and enhanced seizure susceptibility. Among them, the hyperactivity was rapidly improved by pharmacological NMDAR activation. These results suggest that NGL-3 regulates brain development, Akt/GSK3β signaling, LTD, and locomotive and cognitive behaviors.

NKG2D and Its Ligand MULT1 Contribute to Disease Progression in a Mouse Model of Multiple Sclerosis

NKG2D is an activating receptor expressed on the surface of immune cells including subsets of T lymphocytes. NKG2D binds multiple ligands (NKG2DL) whose expression are differentially triggered in a cell type and stress specific manner. The NKG2D-NKG2DL interaction has been involved in autoimmune disorders but its role in animal models of multiple sclerosis (MS) remains incompletely resolved. Here we show that NKG2D and its ligand MULT1 contribute to the pathobiology of experimental autoimmune encephalomyelitis (EAE). MULT1 protein levels are increased in the central nervous system (CNS) at EAE disease peak; soluble MULT1 is elevated in the cerebrospinal fluid of both active and passive EAE. We establish that such soluble MULT1 enhances effector functions (e.g., IFNγ production) of activated CD8 T lymphocytes from wild type but not from NKG2D-deficient (Klrk1^−/−) mice in vitro. The adoptive transfer of activated T lymphocytes from wild type donors induced a significantly reduced EAE disease in Klrk1^−/− compared to wild type (Klrk1^+/+) recipients. Characterization of T lymphocytes infiltrating the CNS of recipient mice shows that donor (CD45.1) rather than endogenous (CD45.2) CD4 T cells are the main producers of key cytokines (IFNγ, GM-CSF). In contrast, infiltrating CD8 T lymphocytes include mainly endogenous (CD45.2) cells exhibiting effector properties (NKG2D, granzyme B and IFNγ). Our data support the notion that endogenous CD8 T cells contribute to passive EAE pathobiology in a NKG2D-dependent manner. Collectively, our results point to the deleterious role of NKG2D and its MULT1 in the pathobiology of a MS mouse model.

Chemokine CXCL10 and Coronavirus-Induced Neurologic Disease

Chemokines (chemotactic cytokines) are involved in a wide variety of biological processes. Following microbial infection, there is often robust chemokine signaling elicited from infected cells, which contributes to both innate and adaptive immune responses that control growth of the invading pathogen. Infection of the central nervous system (CNS) by the neuroadapted John Howard Mueller (JHM) strain of mouse hepatitis virus (JHMV) provides an excellent example of how chemokines aid in host defense as well as contribute to disease. Intracranial inoculation of the CNS of susceptible mice with JHMV results in an acute encephalomyelitis characterized by widespread dissemination of virus throughout the parenchyma. Virus-specific T cells are recruited to the CNS, and control viral replication through release of antiviral cytokines and cytolytic activity. Sterile immunity is not acquired, and virus will persist primarily in white matter tracts leading to chronic neuroinflammation and demyelination. Chemokines are expressed and contribute to defense as well as chronic disease by attracting targeted populations of leukocytes to the CNS. The T cell chemoattractant chemokine CXCL10 (interferon-inducible protein 10 kDa, IP-10) is prominently expressed in both stages of disease, and serves to attract activated T and B lymphocytes expressing CXC chemokine receptor 3 (CXCR3), the receptor for CXCL10. Functional studies that have blocked expression of either CXCL10 or CXCR3 illuminate the important role of this signaling pathway in host defense and neurodegeneration in a model of viral-induced neurologic disease.

Top-down proteomic profiling of human saliva in multiple sclerosis patients

Multiple sclerosis is a chronic disease of the central nervous system characterized by inflammation, demyelination and neurodegeneration which is of undetermined origin. To date a single diagnostic test of multiple sclerosis does not exists and novel biomarkers are demanded for a more accurate and early diagnosis. In this study, we performed the quantitative analysis of 119 salivary peptides/proteins from 49 multiple sclerosis patients and 54 healthy controls by a mass spectrometry-based top-down proteomic approach. Statistical analysis evidenced different levels on 23 proteins: 8 proteins showed lower levels in multiple sclerosis patients with respect to controls and they were mono- and di-oxidized cystatin SN, mono- and di-oxidized cystatin S1, mono-oxidized cystatin SA and mono-phosphorylated statherin. 15 proteins showed higher levels in multiple sclerosis patients with respect to controls and they were antileukoproteinase, two proteoforms of Prolactin-Inducible Protein, P-C peptide (Fr.1-14, Fr. 26-44, and Fr. 36-44), SV1 fragment of statherin, cystatin SN Des_1-4, cystatin SN P₁₁ → L variant, and cystatin A T₉₆ → M variant. The differences observed between the salivary proteomic profile of patients suffering from multiple sclerosis and healthy subjects is consistent with the inflammatory condition and altered immune response typical of the pathology. Data are available via ProteomeXchange with identifier PXD009440.

SIGNIFICANCE

To date a single diagnostic test of multiple sclerosis does not exist, and diagnosis is based on multiple tests which mainly include the analysis of cerebrospinal fluid. However, the need for lumbar puncture makes the analysis of cerebrospinal fluid impractical for monitoring disease activity and response to treatment. The possible use of saliva as a diagnostic fluid for oral and systemic diseases has been largely investigated, but only marginally in multiple sclerosis compared to other body fluids. Our study demonstrates that the salivary proteome of multiple sclerosis patients differs considerably compared to that of sex and age matched healthy individuals and suggests that some differences might be associated with the different disease-modifying therapy used to treat multiple sclerosis patients.

The apparent competitive action of ECM proteases and cross-linking enzymes during fibrosis: Applications to drug discovery

Progressive loss of organ function in most organs is associated with fibrosis, a tissue state associated with abnormal matrix buildup. If highly progressive, the fibrotic process eventually leads to organ failure and death. Fibrosis is a basic connective tissue lesion defined by the increase in the amount of fibrillar extracellular matrix (ECM) components in a tissue or organ. In addition, intrinsic changes in important structural cells can induce the fibrotic response by regulating the differentiation, recruitment, proliferation and activation of extracellular matrix-producing myofibroblasts. ECM enzymes belonging to the family of matrix metalloproteinases (MMPs) and lysyl oxidases (LOXs) play a crucial role in ECM remodeling and regeneration. MMPs have a catalytic role in degradation of ECM, whereas LOX/LOXLs mediate ECM, especially collagen, cross-linking and stiffening. Importantly, enzymes from both families are elevated during the fibrotic response to tissue injury and its resolution. Yet, the apparent molecular competition or antagonistic activities of these enzyme families during the various stages of fibrosis is often overlooked. In this review, we discuss the diverse roles of MMPs and LOX/LOXL2 in chronic organ fibrosis. Finally, we review contemporary therapeutic strategies for fibrosis treatment, based on neutralization of MMP and LOX activity, as well as the development of novel drug delivery approaches.

Neutrophils: a cornerstone of liver ischemia and reperfusion injury

Ischemia-reperfusion injury (IRI) is the main cause of morbidity and mortality due to graft rejection after liver transplantation. During IRI, an intense inflammatory process occurs in the liver. This hepatic inflammation is initiated by the ischemic period but occurs mainly during the reperfusion phase, and is characterized by a large neutrophil recruitment to the liver. Production of cytokines, chemokines, and danger signals results in activation of resident hepatocytes, leukocytes, and Kupffer cells. The role of neutrophils as the main amplifiers of liver injury in IRI has been recognized in many publications. Several studies have shown that elimination of excessive neutrophils or inhibition of their function leads to reduction of liver injury and inflammation. However, the mechanisms involved in neutrophil recruitment during liver IRI are not well known. In addition, the molecules necessary for this type of migration are poorly defined, as the liver presents an atypical sinusoidal vasculature in which the classical leukocyte migration paradigm only partially applies. This review summarizes recent advances in neutrophil-mediated liver damage, and its application to liver IRI. Basic mechanisms of activation of neutrophils and their unique mechanisms of recruitment into the liver vasculature are discussed. In particular, the role of danger signals, adhesion molecules, chemokines, glycosaminoglycans (GAGs), and metalloproteinases is explored. The precise definition of the molecular events that govern the recruitment of neutrophils and their movement into inflamed tissue may offer new therapeutic alternatives for hepatic injury by IRI and other inflammatory diseases of the liver.

Vascular pathology in multiple sclerosis: reframing pathogenesis around the blood-brain barrier

Blood-brain barrier (BBB) disruption has long been recognised as an important early feature of multiple sclerosis (MS) pathology. Traditionally, this has been seen as a by-product of the myelin-specific immune response. Here, we consider whether vascular changes instead play a central role in disease pathogenesis, rather than representing a secondary effect of neuroinflammation or neurodegeneration. Importantly, this is not necessarily mutually exclusive from current hypotheses. Vascular pathology in a genetically predisposed individual, influenced by environmental factors such as pathogens, hypovitaminosis D and smoking, may be a critical initiator of a series of events including hypoxia, protein deposition and immune cell egress that allows the development of a CNS-specific immune response and the classical pathological and clinical hallmarks of disease. We review the changes that occur in BBB function and cerebral perfusion in patients with MS and highlight genetic and environmental risk factors that, in addition to modulating immune function, may also converge to act on the vasculature. Further context is provided by contrasting these changes with other neurological diseases in which there is also BBB malfunction, and highlighting current disease-modifying therapies that may also have an effect on the BBB. Indeed, in reframing current evidence in this model, the vasculature could become an important therapeutic target in MS.

Platelets, inflammation and tissue regeneration

Blood platelets have long been recognised to bring about primary haemostasis with deficiencies in platelet production and function manifesting in bleeding while upregulated function favourises arterial thrombosis. Yet increasing evidence indicates that platelets fulfil a much wider role in health and disease. First, they store and release a wide range of biologically active substances including the panoply of growth factors, chemokines and cytokines released from α-granules. Membrane budding gives rise to microparticles (MPs), another active participant within the blood stream. Platelets are essential for the innate immune response and combat infection (viruses, bacteria, micro-organisms). They help maintain and modulate inflammation and are a major source of pro-inflammatory molecules (e.g. P-selectin, tissue factor, CD40L, metalloproteinases). As well as promoting coagulation, they are active in fibrinolysis; wound healing, angiogenesis and bone formation as well as in maternal tissue and foetal vascular remodelling. Activated platelets and MPs intervene in the propagation of major diseases. They are major players in atherosclerosis and related diseases, pathologies of the central nervous system (Alzheimers disease, multiple sclerosis), cancer and tumour growth. They participate in other tissue-related acquired pathologies such as skin diseases and allergy, rheumatoid arthritis, liver disease; while, paradoxically, autologous platelet-rich plasma and platelet releasate are being used as an aid to promote tissue repair and cellular growth. The above mentioned roles of platelets are now discussed.

Kallikrein 6 secreted by oligodendrocytes regulates the progression of experimental autoimmune encephalomyelitis

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system (CNS), and experimental autoimmune encephalomyelitis (EAE) is a well-established animal model of the disease. Here, we examined the pathophysiological role of Kallikrein 6 (Klk6), a serine protease produced by oligodendrocytes (OLs), in EAE using Klk6 knockout (Klk6-/-) mice. Compared with Klk6+/+ (wild-type) mice, Klk6-/- mice showed milder EAE symptoms, including delayed onset and milder paralysis. Loss of Klk6 suppressed matrix metalloprotease-9 expression and diminished the infiltration of peripheral inflammatory cells into the CNS by decreasing blood-brain barrier (BBB) permeability and reducing expression levels of inflammatory cytokines, chemokines and their receptors. Scanning electron microscopic analysis revealed demyelination characterized by myelin detachment from the axons in the early phase of EAE progression (days 3-7) in Klk6+/+ mice but not in Klk6-/- mice. Interestingly, anti-MOG (myelin oligodendrocyte glycoprotein) autoantibody was also detected in the cerebrospinal fluid (CSF) and spinal cord on day 3 after MOG immunization. Furthermore, treatment of primary cultured OLs with anti-MOG autoantibody induced oligodendroglial morphological changes and increases in myelin basic protein and Klk6 expression. We also developed a novel enzyme-linked immunoabsorbent assay method for detecting activated KLK6 in human CSF. In human autopsy brain samples, expression of active KLK6 was detected in OLs using an antibody that specifically recognizes the protein's activated form. Taken together, our findings demonstrate that Klk6 secreted by OLs plays a critical role in the pathogenesis of EAE/MS and that it might serve as a potential therapeutic target for MS.

Comparative efficacy of immunohistochemical markers in surgical healing

OBJECTIVE

to evaluate the efficacy of three immunohistochemical markers involved in the wound healing process.

METHODS

experimental study of 40 Wistar rats of the markers metalloproteinases and matrix metalloproteinase 9 (MMP-9), beta transforming growth factor (TGF-β) and myofibroblasts and smooth muscle actin alpha (α-MLA) markers, studied from fragments of surgical scar of abdominal incision involving skin, aponeurosis and peritoneum. The animals were divided into four subgroups of ten according to the day of death, scheduled in three, seven, 14 and 21 days.

RESULTS

MMP-9 expression showed a progressive increase of its concentration, more evident from 7th to 14th days, varying the tissue immunoexpression between 2.65% and 11.50% . TGF- β showed expression at high level on the 3rd day, fell in the 7th, rising again in the 14th, with a small decrease in the 21st day, varying the tissue immunoexpression between 0.03% and 2.92%. The α-AML presented levels with little variation and a slight increase, varying the tissue immunoexpression between 0.88% and 3.23%.

CONCLUSION

MMP-9 presented as the best marker, followed by TGF-β. However, α-AML was not a good indicator of the evolution of tissue repair.

Therapeutic effects of walnut oil on the animal model of multiple sclerosis

OBJECTIVES

Therapeutic approaches for multiple sclerosis (MS), an autoimmune disease of the central nervous system (CNS), are accompanied by various undesirable side effects. Owing to the anti-inflammatory and antioxidant effects of walnut, we investigated its effects on the experimental autoimmune encephalomyelitis (EAE) mouse model of MS.

METHODS

After EAE induction in mice, the treated group was gavaged daily with walnut oil. The weights and clinical symptoms were monitored daily for 21 days following the onset of symptoms. The spleens and brains of the mouse were removed and used for ELISA and histological studies.

RESULTS

The average disease severity and plaque formation in the brains of the walnut oil-treated group were significantly lower (P < 0.05) than those of the untreated group. Stimulated splenocytes of the treated group expressed significantly less INF-γ and interleukin (IL)-17 than the untreated group with no significant differences in IL-10 or IL-5 production. In serum from the treated group, IL-17 expression was also significantly less than in the untreated group, while IL-10 was greater (P < 0.05).

CONCLUSION

Walnut oil significantly reduced disease severity, inhibited plaque formation, and altered cytokine production. More studies are required to identify the mechanism of action of walnut oil as a valuable supplement in the treatment of MS.

Resveratrol for Alzheimer's disease

The amyloid hypothesis suggests that the progressive accumulation and deposition of central nervous system (CNS) amyloid with aging is the proximate cause of Alzheimer's disease (AD). Thus, targeting molecular mechanisms of aging may be a viable treatment approach. Caloric restriction prevents diseases of aging, including AD, in animal models, perhaps by activation of sirtuins. The sirtuins (e.g., mammalian SIRT1) are deacetylases that link energy balance (NAD+ /NADH) to regulation of gene transcription. Resveratrol is a potent activator of SIRT1, and thus may mimic caloric restriction to prevent diseases of aging. We conducted a randomized, double-blind, placebo-controlled, phase II trial of resveratrol for individuals with mild-to-moderate AD. Resveratrol (1) is detectable in cerebrospinal fluid (at low nanomolar levels), (2) is safe and well tolerated, (3) alters AD biomarker trajectories, (4) preserves blood-brain barrier integrity, and (5) modulates the CNS immune response. Further studies are needed to determine the safety and efficacy of resveratrol and the validity of this approach in the treatment and prevention of AD and other diseases of aging.

Second Generation Triple-Helical Peptide Inhibitors of Matrix Metalloproteinases

The design of selective matrix metalloproteinase (MMP) inhibitors that also possess favorable solubility properties has proved to be especially challenging. A prior approach using collagen-model templates combined with transition state analogs produced a first generation of triple-helical peptide inhibitors (THPIs) that were effective in vitro against discrete members of the MMP family. These THPI constructs were also highly water-soluble. The present study sought improvements in the first generation THPIs by enhancing thermal stability and selectivity. A THPI selective for MMP-2 and MMP-9 was redesigned to incorporate non-native amino acids (Flp and mep), resulting in an increase of 18 °C in thermal stability. This THPI was effective in vivo in a mouse model of multiple sclerosis, reducing clinical severity and weight loss. Two other THPIs were developed to be more selective within the collagenolytic members of the MMP family. One of these THPIs was serendipitously more effective against MMP-8 than MT1-MMP and was utilized successfully in a mouse model of sepsis. The THPI targeting MMP-8 minimized lung damage, increased production of the anti-inflammatory cytokine IL-10, and vastly improved mouse survival.

Amelioration of Experimental Autoimmune Encephalomyelitis in Mice by Interferon-Beta Gene Therapy, Using a Long-Term Expression Plasmid Vector

Multiple sclerosis (MS) is an inflammatory demyelinating disease of the central nervous system. Repeated injections of the interferon-β (IFN-β) protein are required for relapse prevention therapy in patients with MS. IFN-β gene transfer can be an alternative treatment that continuously supplies IFN-β protein to the patient without requiring repeated injections. In a previous study, we constructed a novel long-term IFN-β-expressing plasmid vector (pMx-IFN-β). In the present study, we examined whether gene transfer of pMx-IFN-β could be effective for the treatment of MS in experimental autoimmune encephalomyelitis (EAE), a mouse model of MS. Seven days after injection of the EAE-inducing peptide, the EAE mice received hydrodynamic injections pMx-IFN-β. The severity of EAE symptoms in the pMx-IFN-β-treated mice was significantly lower for 1 month than that observed in the untreated mice. An evaluation of blood-brain barrier (BBB) function, using Evans Blue, showed that injection of pMx-IFN-β suppressed the BBB disruptions normally observed in EAE mice, while BBB disruptions remained evident in the untreated EAE mice. Histological analysis showed fewer invasive inflammatory cells in the spinal cords of the pMx-IFN-β-treated mice than in the spinal cords of the other mice. Serum interferon gamma protein (IFN-γ) concentrations in the pMx-IFN-β-treated mice were significantly lower than that in the untreated mice, indicating that IFN-β gene transfer suppressed the production of IFN-γ from pathogenic T cells. These results indicate that IFN-β transgene expression by single administration of the pMx-IFN-β can be an effective long-term treatment for MS.

Resveratrol regulates neuro-inflammation and induces adaptive immunity in Alzheimer's disease

Background

Treatment of mild-moderate Alzheimer’s disease (AD) subjects (N = 119) for 52 weeks with the SIRT1 activator resveratrol (up to 1 g by mouth twice daily) attenuates progressive declines in CSF Aβ40 levels and activities of daily living (ADL) scores.

Methods

For this retrospective study, we examined banked CSF and plasma samples from a subset of AD subjects with CSF Aβ42 <600 ng/ml (biomarker-confirmed AD) at baseline (N = 19 resveratrol-treated and N = 19 placebo-treated). We utilized multiplex Xmap technology to measure markers of neurodegenerative disease and metalloproteinases (MMPs) in parallel in CSF and plasma samples.

Results

Compared to the placebo-treated group, at 52 weeks, resveratrol markedly reduced CSF MMP9 and increased macrophage-derived chemokine (MDC), interleukin (IL)-4, and fibroblast growth factor (FGF)-2. Compared to baseline, resveratrol increased plasma MMP10 and decreased IL-12P40, IL12P70, and RANTES. In this subset analysis, resveratrol treatment attenuated declines in mini-mental status examination (MMSE) scores, change in ADL (ADCS-ADL) scores, and CSF Aβ42 levels during the 52-week trial, but did not alter tau levels.

Conclusions

Collectively, these data suggest that resveratrol decreases CSF MMP9, modulates neuro-inflammation, and induces adaptive immunity. SIRT1 activation may be a viable target for treatment or prevention of neurodegenerative disorders.

Trial registration

ClinicalTrials.gov NCT01504854

The effect of 1, 25(OH)2 D3 (calcitriol) alone and in combination with all-trans retinoic acid on ROR-γt, IL-17, TGF-β, and FOXP3 gene expression in experimental autoimmune encephalomyelitis

OBJECTIVES

It has been shown that calcitriol and all-trans retinoic acid (ATRA) have modulatory effects on the immune system. The present study investigates the synergistic effects of combination treatment of calcitriol and ATRA in experimental autoimmune encephalomyelitis (EAE), an animal model of multiple sclerosis (MS).

METHODS

The mice were allocated to four preventive groups, each consisting of eight animals, ATRA (250 μg/mouse), calcitriol (100 ng/mouse), combination of ATRA and calcitriol (125  μg/mouse and 50 ng/mouse) and vehicle groups. EAE was induced by MOG35-55 peptide in female C57BL/6 mice. Treatments were initiated at day 1 before immunization and continued every other day throughout the study until the day 21 post-immunization. Splenocytes were isolated from EAE-induced mice and the expression of retinoic acid receptor-related orphan receptor gamma t (ROR-γt), Interleukin-17 (IL-17), transforming growth factor beta (TGF-β), and forkhead box P3 (FOXP3) genes was measured using real-time polymerase chain reaction.

RESULTS

The expression of FOXP3 and TGF-β genes in the splenocytes of combination-treated and calcitriol alone-treated mice was significantly increased compared to vehicle group (P < 0.05). The expression of ROR-γt and IL-17 genes in the splenocytes of ATRA, calcitriol and combination- treated mice was significantly reduced compared to those of vehicle- treated mice (P < 0.05). The relative expression level of ROR-γt was significantly (P < 0.05) lower in the combination group than in the mice treated by ATRA or calcitriol alone.

DISCUSSION

This study demonstrated that treatment with combination of calcitriol and ATRA can be considered as a new strategy for MS prevention and treatment.

Blood-brain barrier and intestinal epithelial barrier alterations in autism spectrum disorders

Background

Autism spectrum disorders (ASD) are complex conditions whose pathogenesis may be attributed to gene–environment interactions. There are no definitive mechanisms explaining how environmental triggers can lead to ASD although the involvement of inflammation and immunity has been suggested. Inappropriate antigen trafficking through an impaired intestinal barrier, followed by passage of these antigens or immune-activated complexes through a permissive blood–brain barrier (BBB), can be part of the chain of events leading to these disorders. Our goal was to investigate whether an altered BBB and gut permeability is part of the pathophysiology of ASD.

Methods

Postmortem cerebral cortex and cerebellum tissues from ASD, schizophrenia (SCZ), and healthy subjects (HC) and duodenal biopsies from ASD and HC were analyzed for gene and protein expression profiles. Tight junctions and other key molecules associated with the neurovascular unit integrity and function and neuroinflammation were investigated.

Results

Claudin (CLDN)-5 and -12 were increased in the ASD cortex and cerebellum. CLDN-3, tricellulin, and MMP-9 were higher in the ASD cortex. IL-8, tPA, and IBA-1 were downregulated in SCZ cortex; IL-1b was increased in the SCZ cerebellum. Differences between SCZ and ASD were observed for most of the genes analyzed in both brain areas. CLDN-5 protein was increased in ASD cortex and cerebellum, while CLDN-12 appeared reduced in both ASD and SCZ cortexes. In the intestine, 75% of the ASD samples analyzed had reduced expression of barrier-forming TJ components (CLDN-1, OCLN, TRIC), whereas 66% had increased pore-forming CLDNs (CLDN-2, -10, -15) compared to controls.

Conclusions

In the ASD brain, there is an altered expression of genes associated with BBB integrity coupled with increased neuroinflammation and possibly impaired gut barrier integrity. While these findings seem to be specific for ASD, the possibility of more distinct SCZ subgroups should be explored with additional studies.

Interplay between Matrix Metalloproteinase-9, Matrix Metalloproteinase-2, and Interleukins in Multiple Sclerosis Patients

Matrix Metalloproteases (MMPs) and cytokines have been involved in the pathogenesis of multiple sclerosis (MS). However, no studies have still explored the possible associations between the two families of molecules. The present study aimed to evaluate the contribution of active MMP-9, active MMP-2, interleukin- (IL-) 17, IL-18, IL-23, and monocyte chemotactic proteins-3 to the pathogenesis of MS and the possible interconnections between MMPs and cytokines. The proteins were determined in the serum and cerebrospinal fluid (CSF) of 89 MS patients and 92 other neurological disorders (OND) controls. Serum active MMP-9 was increased in MS patients and OND controls compared to healthy subjects (p < 0.001 and p < 0.01, resp.), whereas active MMP-2 and ILs did not change. CSF MMP-9, but not MMP-2 or ILs, was selectively elevated in MS compared to OND (p < 0.01). Regarding the MMPs and cytokines intercorrelations, we found a significant association between CSF active MMP-2 and IL-18 (r = 0.3, p < 0.05), while MMP-9 did not show any associations with the cytokines examined. Collectively, our results suggest that active MMP-9, but not ILs, might be a surrogate marker for MS. In addition, interleukins and MMPs might synergistically cooperate in MS, indicating them as potential partners in the disease process.

Matrix Metalloproteinases in Non-Neoplastic Disorders

The matrix metalloproteinases (MMPs) are zinc-dependent endopeptidases belonging to the metzincin superfamily. There are at least 23 members of MMPs ever reported in human, and they and their substrates are widely expressed in many tissues. Recent growing evidence has established that MMP not only can degrade a variety of components of extracellular matrix, but also can cleave and activate various non-matrix proteins, including cytokines, chemokines and growth factors, contributing to both physiological and pathological processes. In normal conditions, MMP expression and activity are tightly regulated via interactions between their activators and inhibitors. Imbalance among these factors, however, results in dysregulated MMP activity, which causes tissue destruction and functional alteration or local inflammation, leading to the development of diverse diseases, such as cardiovascular disease, arthritis, neurodegenerative disease, as well as cancer. This article focuses on the accumulated evidence supporting a wide range of roles of MMPs in various non-neoplastic diseases and provides an outlook on the therapeutic potential of inhibiting MMP action.

Serum Gelatinases Levels in Multiple Sclerosis Patients during 21 Months of Natalizumab Therapy

Background. Natalizumab is a highly effective treatment approved for multiple sclerosis (MS). The opening of the blood-brain barrier mediated by matrix metalloproteinases (MMPs) is considered a crucial step in MS pathogenesis. Our goal was to verify the utility of serum levels of active MMP-2 and MMP-9 as biomarkers in twenty MS patients treated with Natalizumab. Methods. Serum levels of active MMP-2 and MMP-9 and of specific tissue inhibitors TIMP-1 and TIMP-2 were determined before treatment and for 21 months of therapy. Results. Serum levels of active MMP-2 and MMP-9 and of TIMP-1 and TIMP-2 did not differ during the treatment. The ratio between MMP-9 and MMP-2 was increased at the 15th month compared with the 3rd, 6th, and 9th months, greater at the 18th month than at the 3rd and 6th months, and higher at the 21st than at the 3rd and 6th months. Discussion. Our data indicate that an imbalance between active MMP-9 and active MMP-2 can occur in MS patients after 15 months of Natalizumab therapy; however, they do not support the use of serum active MMP-2 and active MMP-9 and TIMP-1 and TIMP-2 levels as biomarkers for monitoring therapeutic response to Natalizumab.

Analysis of MMP2-1306C/T and TIMP2G-418C polymorphisms with relapsing remitting multiple sclerosis

AIMS

Multiple sclerosis (MS) is an autoimmune, inflammatory disease characterized by loss of myelin forming oligodendrocytes and changes in the blood-brain barrier. Matrix metalloproteinase (MMP) -2 and -9 are known to cause disruption of the blood-brain barrier, remodeling of the basal lamina, regeneration of axons, and remyelination in MS. The imbalance between MMPs and tissue inhibitor metalloproteinases (TIMPs) may lead to the emergence of pathological processes such as MS. The roles of MMP2-1306 C/T and TIMP2-418 G/C genetic variants in MS have not been studied before. We aimed to investigate whether MMP2-1306C/T and TIMP2-418 G/C gene variants are risk factors for patients with relapsing remitting multiple sclerosis (RRMS).

METHODS

The study included 102 RRMS and 102 healthy controls. Genomic DNA was extracted from peripheral leukocytes from ethylenediaminetetraacetic acid anticoagulated blood. Genotyping of the MMP2-1306C/T and TIMP2G-418C polymorphisms was performed using real-time PCR.

RESULTS

There were significant differences in terms of distribution of genotype (MMP2-1306- CT, TT) and T allele frequency between the patients with RRMS and the control group (p<0.0001; p<0.0001). The groups were not different in terms of TIMP2G-418C polymorphisms.

CONCLUSIONS

In the RRMS group, the genotype and allele frequencies of MMP2-1306C/T polymorphism showed significant differences from the controls. These results indicate that MMP2 might play a role in the pathogenesis of MS even during the inflammation stage.

MMP-9 in translation: from molecule to brain physiology, pathology, and therapy

Matrix metalloproteinase-9 (MMP-9) is a member of the metzincin family of mostly extracellularly operating proteases. Despite the fact that all of these enzymes might be target promiscuous, with largely overlapping catalogs of potential substrates, MMP-9 has recently emerged as a major and apparently unique player in brain physiology and pathology. The specificity of MMP-9 may arise from its very local and time-restricted actions, even when released in the brain from cells of various types, including neurons, glia, and leukocytes. In fact, the quantity of MMP-9 is very low in the naive brain, but it is markedly activated at the levels of enzymatic activity, protein abundance, and gene expression following various physiological stimuli and pathological insults. Neuronal MMP-9 participates in synaptic plasticity by controlling the shape of dendritic spines and function of excitatory synapses, thus playing a pivotal role in learning, memory, and cortical plasticity. When improperly unleashed, MMP-9 contributes to a large variety of brain disorders, including epilepsy, schizophrenia, autism spectrum disorder, brain injury, stroke, neurodegeneration, pain, brain tumors, etc. The foremost mechanism of action of MMP-9 in brain disorders appears to be its involvement in immune/inflammation responses that are related to the enzyme's ability to process and activate various cytokines and chemokines, as well as its contribution to blood-brain barrier disruption, facilitating the extravasation of leukocytes into brain parenchyma. However, another emerging possibility (i.e., the control of MMP-9 over synaptic plasticity) should not be neglected. The translational potential of MMP-9 has already been recognized in both the diagnosis and treatment domains. The most striking translational aspect may be the discovery of MMP-9 up-regulation in a mouse model of Fragile X syndrome, quickly followed by human studies and promising clinical trials that have sought to inhibit MMP-9. With regard to diagnosis, suggestions have been made to use MMP-9 alone or combined with tissue inhibitor of matrix metalloproteinase-1 or brain-derived neurotrophic factor as disease biomarkers. MMP-9, through cleavage of specific target proteins, plays a major role in synaptic plasticity and neuroinflammation, and by those virtues contributes to brain physiology and a host of neurological and psychiatric disorders. This article is part of the 60th Anniversary special issue.