Plasma osteopontin levels in multiple sclerosis

Past, present, and future biomarkers of kidney function and injury: The relationship with antibiotics

Routinely used kidney biomarkers of injury and function such as serum creatinine and urine albumin to creatinine ratio, are neither sensitive nor specific. Future biomarkers are being developed for clinical use and have already been included in guidance from groups such as the U.S. Food and Drug Administration and the Predictive Safety Testing Consortium. These biomarkers have important implications for early identification of kidney injury and more accurate measurement of kidney function. Many antibiotics are either eliminated by the kidney or can cause clinically significant nephrotoxicity. As a result, clinicians should be familiar with new biomarkers of kidney function and injury, their place in clinical practice, and applications for antibiotic dosing.

Osteopontin predicts late-time salience network-related functional connectivity in multiple sclerosis

Resting-state functional magnetic resonance imaging (rs-fMRI) has been widely utilized to investigate plasticity mechanisms and functional reorganization in multiple sclerosis (MS). Among many resting state (RS) networks, a significant role is played by the salience network (SN, ventral attention network). Previous reports have demonstrated the involvement of osteopontin (OPN) in the pathogenesis of MS, which acts as a proinflammatory cytokine ultimately leading to neurodegeneration. Concentration of serum OPN was related to MRI findings 10.22±2.84 years later in 44 patients with MS. Local and interhemispheric correlations (LCOR, IHC), ROI-to-ROI and seed-based connectivity analyses were performed using serum OPN levels as independent variable along with age and gender as nuisance variables. We found significant associations between OPN levels and local correlation in right and left clusters encompassing the central opercular- and insular cortices (p-FDR = 0.0018 and p-FDR = 0.0205, respectively). Moreover, a significant association was identified between OPN concentration and interhemispheric correlation between central opercular- and insular cortices (p-FDR = 0.00015). Significant positive associations were found between OPN concentration and functional connectivity (FC) within the SN (FC strength between the anterior insula ventral division and 3 other insular regions, F(2,13) = 7.84, p-FDR = 0.0117). Seed-based connectivity analysis using the seven nodes of the SN resulted in several positive and inverse associations with OPN level. Serum OPN level may predict FC alterations within the SN in 10 years.

Assessment of serum inflammatory parameters in RRMS and SPMS patients

OBJECTIVES

Multiple sclerosis (MS) is a chronic autoimmune inflammatory disease. Patients with relapsing-remitting MS (RRMS) and secondary progressive MS (SPMS) differ in their responses to treatment; therefore, the correct diagnosis of the particular type of MS is crucial, and biomarkers that can differentiate between the forms of MS need to be identified. The aim of this study was to compare the levels of inflammatory parameters in serum samples from patients with RRMS and SPMS.

METHODS

The study group consisted of 60 patients with diagnosed MS. The patients were divided into RRMS and SPMS groups. In the RRMS patients, the usage of disease-modifying treatment was included in our analysis. The serum levels of inflammatory parameters were evaluated.

RESULTS

The serum levels of BAFF, gp130 and osteopontin were significantly higher in SPMS patients than in RRMS patients. The serum levels of BAFF correlated with age in both RRMS and SPMS patients. The serum levels of MMP-2 were significantly higher in RRMS patients than in SPMS patients and correlated with the number of past relapses. The serum levels of IL-32 were significantly higher in RRMS treatment-naïve patients than in RRMS patients treated with disease-modifying therapy.

DISCUSSION

Significant differences were found in BAFF, gp130, MMP-2 and osteopontin levels between RRMS and SPMS patients. Serum IL-32 levels were statistically lower in RRMS patients treated with disease-modifying therapy than in treatment-naïve patients.

Understanding multiple sclerosis as a disease spectrum: above and below the clinical threshold

PURPOSE OF REVIEW

Research in multiple sclerosis (MS) has long been predicated on clinical groupings that do not reflect the underlying biologic heterogeneity apparent within patient populations. This review explicates the various levels of explanation through which the spectrum of disease is described and investigated both above and below the clinical threshold of detection, as framed by the topographical model of MS, to help advance a cogent mechanistic framework.

RECENT FINDINGS

Contemporary evidence has amended the view of MS as consisting of sequential disease phases in favor of a spectrum of disease with an admixture of interdependent and dynamic pathobiological axes driving tissue injury and progression. Recent studies have shown the presence of acute and compartmentalized inflammation and mechanisms of neurodegeneration beginning early and evolving throughout the disease continuum. Still, the gap between the understanding of immunopathologic processes in MS and the tools used to measure relevant molecular, laboratory, radiologic, and clinical metrics needs attention to enable better prognostication of disease and monitoring for changes along specific pathologic axes and variable treatment outcomes.

SUMMARY

Aligning on a consistently-applied mechanistic framework at distinct levels of explanation will enable greater precision across bench and clinical research, and inform discourse on drivers of disability progression and delivery of care for individuals with MS.

Microglial- neuronal crosstalk in chronic viral infection through mTOR, SPP1/OPN and inflammasome pathway signaling

HIV-infection of microglia and macrophages (MMs) induces neuronal injury and chronic release of inflammatory stimuli through direct and indirect molecular pathways. A large percentage of people with HIV-associated neurologic and psychiatric co-morbidities have high levels of circulating inflammatory molecules. Microglia, given their susceptibility to HIV infection and long-lived nature, are reservoirs for persistent infection. MMs and neurons possess the molecular machinery to detect pathogen nucleic acids and proteins to activate innate immune signals. Full activation of inflammasome assembly and expression of IL-1β requires a priming event and a second signal. Many studies have demonstrated that HIV infection alone can activate inflammasome activity. Interestingly, secreted phosphoprotein-1 (SPP1/OPN) expression is highly upregulated in the CNS of people infected with HIV and neurologic dysfunction. Interestingly, all evidence thus far suggests a protective function of SPP1 signaling through mammalian target of rapamycin (mTORC1/2) pathway function to counter HIV-neuronal injury. Moreover, HIV-infected mice knocked down for SPP1 show by neuroimaging, increased neuroinflammation compared to controls. This suggests that SPP1 uses unique regulatory mechanisms to control the level of inflammatory signaling. In this mini review, we discuss the known and yet-to-be discovered biological links between SPP1-mediated stimulation of mTOR and inflammasome activity. Additional new mechanistic insights from studies in relevant experimental models will provide a greater understanding of crosstalk between microglia and neurons in the regulation of CNS homeostasis.

The Interplay between Meningeal Lymphatic Vessels and Neuroinflammation in Neurodegenerative Diseases

Meningeal lymphatic vessels (MLVs) are essential for the drainage of cerebrospinal fluid, macromolecules, and immune cells in the central nervous system. They play critical roles in modulating neuroinflammation in neurodegenerative diseases. Dysfunctional MLVs have been demonstrated to increase neuroinflammation by horizontally blocking the drainage of neurotoxic proteins to the peripheral lymph nodes. Conversely, MLVs protect against neuroinflammation by preventing immune cells from becoming fully encephalitogenic. Furthermore, evidence suggests that neuroinflammation affects the structure and function of MLVs, causing vascular anomalies and angiogenesis. Although this field is still in its infancy, the strong link between MLVs and neuroinflammation has emerged as a potential target for slowing the progression of neurodegenerative diseases. This review provides a brief history of the discovery of MLVs, introduces in vivo and in vitro MLV models, highlights the molecular mechanisms through which MLVs contribute to and protect against neuroinflammation, and discusses the potential impact of neuroinflammation on MLVs, focusing on recent progress in neurodegenerative diseases.

A comparison of serum inflammatory parameters in progressive forms of multiple sclerosis

INTRODUCTION

Multiple sclerosis (MS) is a chronic, inflammatory demyelinating disease of the central nervous system. Primary progressive MS (PPMS) is diagnosed in approximately 10-15 % of MS patients. Disease-modifying therapies (DMT) are less effective in modifying the course of progressive types of MS. It seems that inflammatory processes differ in the MS subtypes.

OBJECTIVES

The objective of this study was to assess differences in the inflammatory parameters between PPMS and other courses of MS.

MATERIALS AND METHODS

A total of 84 subjects were included in the study. The study group was divided according to the course of MS into the following categories: PPMS (n = 24); SPMS-secondary progressive multiple sclerosis (n = 14); RRMS-relapsing-remitting multiple sclerosis (n = 46). PPMS patients were further divided into treated with ocrelizumab and treatment-naive groups. The concentrations of serum inflammatory parameters were evaluated.

RESULTS

PPMS and SPMS significantly differed in the serum levels of sCD30, gp130, sIL-6R alpha, osteopontin, pentraxin-3 and sTNF-R1. The serum concentrations of IFN-alpha2, IL-10, IL-20, IL-29 and osteopontin significantly differed between PPMS and RRMS. The serum levels of BAFF, IL-19, IL-20, pentraxin-3, s-TNF-R1 and s-TNF-R2 significantly differed between PPMS treated with ocrelizumab and treatment-naive.

CONCLUSION

Although inflammatory processes take part in the pathogenesis of all types of MS, they differ between MS courses. Serum inflammatory parameters seem to be promising biomarkers in helping to differentiate courses of MS, and in assessing reactions to DMT treatment. Further investigations on their usage are required.

The Role and Clinical Relevance of Osteopontin in Allergic Airway Diseases

The airway epithelium is exposed to numerous external irritants including infectious agents, environmental allergens, and atmospheric pollutants, releasing epithelial cytokines including thymic stromal lymphopoietin (TSLP), IL-33, and IL-25 and initiating downstream type 2 (IL-4, IL-13, and IL-5) and IgE-driven pathways. These pathways trigger the initiation and progression of allergic airway diseases, including chronic rhinosinusitis with nasal polyps (CRSwNP), allergic rhinitis (AR), and allergic asthma. However, the use of biological agents that target downstream cytokines, such as IL-5, IL-4, and IL-13 receptors and IgE, might not be sufficient to manage some patients successfully. Instead of blocking downstream cytokines, targeting upstream epithelial cytokines has been proposed to address the complex immunologic networks associated with allergic airway diseases. Osteopontin (OPN), an extracellular matrix glyco-phosphoprotein, is a key mediator involved in Th1-related diseases, including systemic lupus erythematosus, multiple sclerosis, inflammatory bowel disease, and rheumatoid arthritis. Emerging evidence, including ours, indicates that epithelial-cell-derived OPN also plays an essential role in Th2-skewed airway diseases, including CRSwNP, AR, and allergic asthma involving the Th17 response. Therefore, we reviewed the current knowledge of epithelial-cell-derived OPN in the pathogenesis of three type-2-biased airway diseases and provided a direction for its future investigation and clinical relevance.

Characterizing microglial gene expression in a model of secondary progressive multiple sclerosis

Multiple sclerosis (MS) is the most common inflammatory, demyelinating and neurodegenerative disease of the central nervous system in young adults. Chronic-relapsing experimental autoimmune encephalomyelitis (crEAE) in Biozzi ABH mice is an experimental model of MS. This crEAE model is characterized by an acute phase with severe neurological disability, followed by remission of disease, relapse of neurological disease and remission that eventually results in a chronic progressive phase that mimics the secondary progressive phase (SPEAE) of MS. In both MS and SPEAE, the role of microglia is poorly defined. We used a crEAE model to characterize microglia in the different phases of crEAE phases using morphometric and RNA sequencing analyses. At the initial, acute inflammation phase, microglia acquired a pro-inflammatory phenotype. At the remission phase, expression of standard immune activation genes was decreased while expression of genes associated with lipid metabolism and tissue remodeling were increased. Chronic phase microglia partially regain inflammatory gene sets and increase expression of genes associated with proliferation. Together, the data presented here indicate that microglia obtain different features at different stages of crEAE and a particularly mixed phenotype in the chronic stage. Understanding the properties of microglia that are present at the chronic phase of EAE will help to understand the role of microglia in secondary progressive MS, to better aid the development of therapies for this phase of the disease.

Osteopontin Is Associated with Multiple Sclerosis Relapses

BACKGROUND

Osteopontin, an extracellular matrix protein involved in bone remodeling, tissue repair and inflammation, has previously been associated with increased inflammation and neurodegeneration in multiple sclerosis (MS), promoting a worse disease course. Osteopontin is also likely involved in acute MS relapses.

METHODS

In 47 patients with relapsing-remitting MS, we explored the correlation between the time elapsed between the last clinical relapse and lumbar puncture, and the cerebrospinal fluid (CSF) levels of osteopontin and a group of inflammatory cytokines and adipokines such as resistin, plasminogen activator inhibitor-1, osteoprotegerin, interleukin (IL)-1β, IL-2, IL-6 and IL-1 receptor antagonist (IL-1ra). We also analyzed the correlations between CSF levels of osteopontin and the other CSF molecules considered.

RESULTS

Osteopontin CSF concentrations were higher in patients with a shorter time interval between the last clinical relapse and CSF withdrawal. In addition, CSF levels of osteopontin were positively correlated with the proinflammatory cytokines IL-2 and IL-6 and negatively correlated with the anti-inflammatory molecule IL-1ra.

CONCLUSIONS

Our results further suggest the role of osteopontin in acute MS relapses showing that, in proximity to relapses, osteopontin expression in CSF may be increased along with other proinflammatory mediators and correlated with decreased concentrations of anti-inflammatory molecules.

Thiol-ene-based microfluidic chips for glycopeptide enrichment and online digestion of inflammation-related proteins osteopontin and immunoglobulin G

Proteins, and more specifically glycoproteins, have been widely used as biomarkers, e.g., to monitor disease states. Bottom-up approaches based on mass spectrometry (MS) are techniques commonly utilized in glycoproteomics, involving protein digestion and glycopeptide enrichment. Here, a dual function polymeric thiol-ene-based microfluidic chip (TE microchip) was applied for the analysis of the proteins osteopontin (OPN) and immunoglobulin G (IgG), which have important roles in autoimmune diseases, in inflammatory diseases, and in coronavirus disease 2019 (COVID-19). TE microchips with larger internal surface features immobilized with trypsin were successfully utilized for OPN digestion, providing rapid and efficient digestion with a residence time of a few seconds. Furthermore, TE microchips surface-modified with ascorbic acid linker (TEA microchip) have been successfully utilized for IgG glycopeptide enrichment. To illustrate the use of the chips for more complex samples, they were applied to enrich IgG glycopeptides from human serum samples with antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The dual functional TE microchips could provide high throughput for online protein digestion and glycopeptide enrichment, showing great promise for future extended applications in proteomics and the study of related diseases.

Osteopontin associates with brain TRM-cell transcriptome and compartmentalization in donors with and without multiple sclerosis

The human brain is populated by perivascular T cells with a tissue-resident memory T (T_RM)-cell phenotype, which in multiple sclerosis (MS) associate with lesions. We investigated the transcriptional and functional profile of freshly isolated T cells from white and gray matter. RNA sequencing of CD8⁺ and CD4⁺ CD69⁺ T cells revealed T_RM-cell signatures. Notably, gene expression hardly differed between lesional and normal-appearing white matter T cells in MS brains. Genes up-regulated in brain T_RM cells were MS4A1 (CD20) and SPP1 (osteopontin, OPN). OPN is also abundantly expressed by microglia and has been shown to inhibit T cell activity. In line with their parenchymal localization and the increased presence of OPN in active MS lesions, we noticed a reduced production of inflammatory cytokines IL-2, TNF, and IFNγ by lesion-derived CD8⁺ and CD4⁺ T cells ex vivo. Our study reports traits of brain T_RM cells and reveals their tight control in MS lesions.

Toward Precision Phenotyping of Multiple Sclerosis

The classification of multiple sclerosis (MS) has been established by Lublin in 1996 and revised in 2013. The revision includes clinically isolated syndrome, relapsing-remitting, primary progressive and secondary progressive MS, and has added activity (i.e., formation of white matter lesions or clinical relapses) as a qualifier. This allows for the distinction between active and nonactive progression, which has been shown to be of clinical importance. We propose that a logical extension of this classification is the incorporation of additional key pathological processes, such as chronic perilesional inflammation, neuroaxonal degeneration, and remyelination. This will distinguish MS phenotypes that may present as clinically identical but are driven by different combinations of pathological processes. A more precise description of MS phenotypes will improve prognostication and personalized care as well as clinical trial design. Thus, our proposal provides an expanded framework for conceptualizing MS and for guiding development of biomarkers for monitoring activity along the main pathological axes in MS.

Osteopontin/secreted phosphoprotein-1 harnesses glial-, immune-, and neuronal cell ligand-receptor interactions to sense and regulate acute and chronic neuroinflammation

Osteopontin (OPN) also known by its official gene designation secreted phosphoprotein-1 (SPP1) is a fascinating, multifunctional protein expressed in a number of cell types that functions not only in intercellular communication, but also in the extracellular matrix (ECM). OPN/SPP1 possesses cytokine, chemokine, and signal transduction functions by virtue of modular structural motifs that provide interaction surfaces for integrins and CD44-variant receptors. In humans, there are three experimentally verified splice variants of OPN/SPP1 and CD44's ten exons are also alternatively spiced in a cell/tissue-specific manner, although very little is known about how this is regulated in the central nervous system (CNS). Post-translational modifications of phosphorylation, glycosylation, and localized cleavage by specific proteases in the cells and tissues where OPN/SPP1 functions, provides additional layers of specificity. However, the former make elucidating the exact molecular mechanisms of OPN/SPP1 function more complex. Flexibility in OPN/SPP1 structure and its engagement with integrins having the ability to transmit signals in inside-out and outside-in direction, is likely why OPN/SPP1 can serve as an early detector of inflammation and ongoing tissue damage in response to cancer, stroke, traumatic brain injury, pathogenic infection, and neurodegeneration, processes that impair tissue homeostasis. This review will focus on what is currently known about OPN/SPP1 function in the brain.

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.

Identification of Potential Biomarkers in the Peripheral Blood Mononuclear Cells of Relapsing-Remitting Multiple Sclerosis Patients

Multiple sclerosis (MS) is described as an immune disorder with inflammation and neurodegeneration. Relapsing-remitting MS (RRMS) is one of the most common types of MS. The diagnostic manner for this disorder typically includes the usage of magnetic resonance imaging (MRI); however, this is not always a very precise diagnostic method. Identification of molecular biomarkers in RRMS body fluids samples compared to healthy subjects can be useful to indicate the normal and pathogenic biological processes or pharmacological responses to drug interaction. In this regard, this study evaluated different miRNAs in isolated peripheral blood mononuclear cells (PBMCs) of RRMS compared to controls and their correlations with altered T regulatory type 1 (Tr1) cells, osteopontin (OPN), and interleukin 10 (IL-10) levels. The frequency of Tr1 cells was measured using flow cytometry. Also, the expressions of different miRNAs were evaluated via quantitative real-time polymerase chain reaction (RT-qPCR) and plasma levels of IL-10 and OPN were tested by enzyme-linked immunosorbent assay (ELISA). The obtained results showed the Tr1 cells' frequency, Let7c-5p, and miR-299-5p levels decreased in RRMS patients to about 59%, 0.69%, and 20% of HCs, respectively, (P < 0.05). The miR-106a-5p levels increased about 7.5-fold in RRMS patients in comparison to HCs (P < 0.05). Moreover, the results showed that there was an increased negative association between Tr1 frequency and plasma-OPN levels in RRMS patients in comparison to HCs and also, we found a moderate positive correlation between plasma-IL-10 and miR-299-5p expression of RRMS patients. Overall, it may be possible to use these biomarkers to improve the diagnostic process. These biomarkers may also be considered for clinical and therapeutic studies in the future.

Single-cell and spatial RNA sequencing identify perturbators of microglial functions with aging

Microglia are the immune sentinels of the central nervous system with protective roles such as the removal of neurotoxic oxidized phosphatidylcholines (OxPCs). As aging alters microglial function and elevates neurological disability in diseases such as multiple sclerosis, defining aging-associated factors that cause microglia to lose their custodial properties or even become injurious can help to restore their homeostasis. We used single-cell and spatial RNA sequencing in the spinal cord of young (6-week-old) and middle-aged (52-week-old) mice to determine aging-driven microglial reprogramming at homeostasis or after OxPC injury. We identified numerous aging-associated microglial transcripts including osteopontin elevated in OxPC-treated 52-week-old mice, which correlated with greater neurodegeneration. Osteopontin delivery into the spinal cords of 6-week-old mice worsened OxPC lesions, while its knockdown in 52-week-old lesions attenuated microglial inflammation and axon loss. Thus, elevation of osteopontin and other transcripts in aging disorders including multiple sclerosis perturbs microglial functions contributing to aging-associated neurodegeneration.

Update on Multiple Sclerosis Molecular Biomarkers to Monitor Treatment Effects

Multiple sclerosis (MS) is an inflammatory and neurodegenerative disease of the central nervous system characterized by broad inter- and intraindividual heterogeneity. The relapse rate, disability progression, and lesion load assessed through MRI are used to detect disease activity and response to treatment. Although it is possible to standardize these characteristics in larger patient groups, so far, this has been difficult to achieve in individual patients. Easily detectable molecular biomarkers can be powerful tools, permitting a tailored therapy approach for MS patients. However, only a few molecular biomarkers have been routinely used in clinical practice as the validation process, and their transfer into clinical practice takes a long time. This review describes the characteristics of an ideal MS biomarker, the challenges of establishing new biomarkers, and promising molecular biomarkers from blood or CSF samples used to monitor MS treatment effects in clinical practice.

Osteopontin in autoimmune disorders: current knowledge and future perspective

Osteopontin (OPN) is a multifunctional cytokine and adhesion molecule, as well as an unusual regulator for both innate and adaptive immune responses. Several immune cells can produce OPN, including dendritic cells (DCs), macrophages, and T lymphocytes. OPN expression is reported to be increased in a wide range of disorders, including autoimmunity, cancer, and allergy. The overexpression of OPN in several autoimmune disorders, such as rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), multiple sclerosis (MS), Type 1 diabetes (T1D), inflammatory bowel disease (IBD), Sjögren's, and myasthenia gravis, have been shown to be correlated with disease severity. Regarding the important regulatory roles of OPN in the immune system, this study aimed to review the role of this molecule in autoimmune disorders and to provide a complete view of the current knowledge in this field.

The role of glial cells in multiple sclerosis disease progression

Despite the development of highly effective treatments for relapsing-remitting multiple sclerosis (MS), limited progress has been made in addressing primary progressive or secondary progressive MS, both of which lead to loss of oligodendrocytes and neurons and axons, and to irreversible accumulation of disability. Neuroinflammation is central to all forms of MS. The current effective therapies for relapsing-remitting MS target the peripheral immune system; these treatments, however, have repeatedly failed in progressive MS. Greater understanding of inflammation driven by CNS-resident cells - including astrocytes and microglia - is, therefore, required to identify novel potential therapeutic opportunities. Advances in imaging, biomarker analysis and genomics suggest that microglia and astrocytes have central roles in the progressive disease process. In this Review, we provide an overview of the involvement of astrocytes and microglia at major sites of pathology in progressive MS. We discuss current and future therapeutic approaches to directly target glial cells, either to inhibit pathogenic functions or to restore homeostatic functions lost during the course of the disease. We also discuss how bidirectional communication between astrocytes and microglia needs to be considered, as therapeutic targeting of one is likely to alter the functions of the other.

The Role of Matrix Proteins in Cardiac Pathology

The extracellular matrix (ECM) and ECM-regulatory proteins mediate structural and cell-cell interactions that are crucial for embryonic cardiac development and postnatal homeostasis, as well as organ remodeling and repair in response to injury. These proteins possess a broad functionality that is regulated by multiple structural domains and dependent on their ability to interact with extracellular substrates and/or cell surface receptors. Several different cell types (cardiomyocytes, fibroblasts, endothelial and inflammatory cells) within the myocardium elaborate ECM proteins, and their role in cardiovascular (patho)physiology has been increasingly recognized. This has stimulated robust research dissecting the ECM protein function in human health and disease and replicating the genetic proof-of-principle. This review summarizes recent developments regarding the contribution of ECM to cardiovascular disease. The clear importance of this heterogeneous group of proteins in attenuating maladaptive repair responses provides an impetus for further investigation into these proteins as potential pharmacological targets in cardiac diseases and beyond.

Osteopontin levels are associated with late-time lower regional brain volumes in multiple sclerosis

Osteopontin (OPN) is a proinflammatory marker produced by systemic immune and central nervous system (CNS) resident cells. We examined, if the level of OPN in the cerebrospinal fluid (CSF) and blood is associated with late-time regional brain volumes and white matter (WM) lesion load in MS. Concentrations of OPN in blood and CSF were related to MRI findings 10.1 ± 2.0 years later in 46 patients with MS. OPN concentration was measured by ELISA, while regional brain volumes and lesion load was assessed by magnetic resonance imaging (MRI) using 3D MPRAGE sequence and automated MR volumetry. OPN measured in the CSF was associated with several regional brain volumes and WM lesion load measured 10.1 ± 2.0 years later. CSF OPN concentration correlated with long-term enlargement of lateral- and inferior lateral ventricles and the elevation of gross CSF volume, in conjunction with the reduction of several cortical/subcortical gray matter and WM volumes. Serum OPN showed no long-term association with regional brain volumes. OPN measured from the CSF but not from the serum was associated with lower regional brain volumes measured a decade later, indicating the primary role of inflammation within the CNS in developing long-term brain related alterations.

Th17-Related Cytokines as Potential Discriminatory Markers between Neuromyelitis Optica (Devic's Disease) and Multiple Sclerosis-A Review

Multiple sclerosis (MS) and Devic’s disease (NMO; neuromyelitis optica) are autoimmune, inflammatory diseases of the central nervous system (CNS), the etiology of which remains unclear. It is a serious limitation in the treatment of these diseases. The resemblance of the clinical pictures of these two conditions generates a partial possibility of introducing similar treatment, but on the other hand, a high risk of misdiagnosis. Therefore, a better understanding and comparative characterization of the immunopathogenic mechanisms of each of these diseases are essential to improve their discriminatory diagnosis and more effective treatment. In this review, special attention is given to Th17 cells and Th17-related cytokines in the context of their potential usefulness as discriminatory markers for MS and NMO. The discussed results emphasize the role of Th17 immune response in both MS and NMO pathogenesis, which, however, cannot be considered without taking into account the broader perspective of immune response mechanisms.

The extracellular matrix as modifier of neuroinflammation and remyelination in multiple sclerosis

Remyelination failure contributes to axonal loss and progression of disability in multiple sclerosis. The failed repair process could be due to ongoing toxic neuroinflammation and to an inhibitory lesion microenvironment that prevents recruitment and/or differentiation of oligodendrocyte progenitor cells into myelin-forming oligodendrocytes. The extracellular matrix molecules deposited into lesions provide both an altered microenvironment that inhibits oligodendrocyte progenitor cells, and a fuel that exacerbates inflammatory responses within lesions. In this review, we discuss the extracellular matrix and where its molecules are normally distributed in an uninjured adult brain, specifically at the basement membranes of cerebral vessels, in perineuronal nets that surround the soma of certain populations of neurons, and in interstitial matrix between neural cells. We then highlight the deposition of different extracellular matrix members in multiple sclerosis lesions, including chondroitin sulphate proteoglycans, collagens, laminins, fibronectin, fibrinogen, thrombospondin and others. We consider reasons behind changes in extracellular matrix components in multiple sclerosis lesions, mainly due to deposition by cells such as reactive astrocytes and microglia/macrophages. We next discuss the consequences of an altered extracellular matrix in multiple sclerosis lesions. Besides impairing oligodendrocyte recruitment, many of the extracellular matrix components elevated in multiple sclerosis lesions are pro-inflammatory and they enhance inflammatory processes through several mechanisms. However, molecules such as thrombospondin-1 may counter inflammatory processes, and laminins appear to favour repair. Overall, we emphasize the crosstalk between the extracellular matrix, immune responses and remyelination in modulating lesions for recovery or worsening. Finally, we review potential therapeutic approaches to target extracellular matrix components to reduce detrimental neuroinflammation and to promote recruitment and maturation of oligodendrocyte lineage cells to enhance remyelination.

Different neuroinflammatory gene expression profiles in highly active and benign multiple sclerosis

In this study, we aimed to explore the expression of genes associated with neuroinflammation in patients with benign and highly active multiple sclerosis (MS) and healthy controls, to define gene signatures associated with MS as well as disease activity and progression. We identified differences in the expression of 89 genes in benign and highly active MS patients and in healthy controls (q < 0.05). Twenty-eight genes related to myeloid cells function, the innate immune response, apoptosis, and autophagy were differentially expressed in patients with benign and highly active MS. Time to second relapse and expanded disability status scale (EDSS) scores were correlated with the expression of genes associated with myeloid cells function, innate immunity, and apoptosis. Our results could indicate the importance of innate immunity-associated pathways in maintaining high disease activity in MS and their crucial role in disease progression.

Curcumin: A Dietary Phytochemical for Targeting the Phenotype and Function of Dendritic Cells

Dendritic cells (DCs) are the most powerful antigen-presenting cells which link the innate and adaptive immune responses. Depending on the context, DCs initiate the immune responses or contribute to immune tolerance. Any disturbance in their phenotypes and functions may initiate inflammatory or autoimmune diseases. Hence, dysregulated DCs are the most attractive pharmacological target for the development of new therapies aiming at reducing their immunogenicity and at enhancing their tolerogenicity. Curcumin is the polyphenolic phytochemical component of the spice turmeric with a wide range of pharmacological activities. It acts in several ways as a modulator of DCs and converts them into tolerogenic DCs. Tolerogenic DCs possess anti-inflammatory and immunomodulatory activities that regulate the immune responses in health and disease. Curcumin by blocking maturation markers, cytokines and chemokines expression, and disrupting the antigen-presenting machinery of DCs render them non- or hypo-responsive to immunostimulants. It also reduces the expression of co-stimulatory and adhesion molecules on DCs and prevents them from both migration and antigen presentation but enhances their endocytosis capacity. Hence, curcumin causes DCs-inducing regulatory T cells and dampens CD4+ T helper 1 (Th1), Th2, and Th17 polarization. Inhibition of transcription factors such as NF-κB, AP-1, MAPKs (p38, JNK, ERK) and other intracellular signaling molecules such as JAK/STAT/SOCS provide a plausible explanation for most of these observations. In this review, we summarize the potential effects of curcumin on the phenotypes and functions of DCs as the key players in orchestration, stimulation, and modulation of the immune responses.

The Evolution of Neurofilament Light Chain in Multiple Sclerosis

Multiple sclerosis (MS) is an autoimmune, inflammatory neurodegenerative disease of the central nervous system characterized by demyelination and axonal damage. Diagnosis and prognosis are mainly assessed through clinical examination and neuroimaging. However, more sensitive biomarkers are needed to measure disease activity and guide treatment decisions in MS. Prompt and individualized management can reduce inflammatory activity and delay disease progression. Neurofilament Light chain (NfL), a neuron-specific cytoskeletal protein that is released into the extracellular fluid following axonal injury, has been identified as a biomarker of disease activity in MS. Measurement of NfL levels can capture the extent of neuroaxonal damage, especially in early stages of the disease. A growing body of evidence has shown that NfL in cerebrospinal fluid (CSF) and serum can be used as reliable indicators of prognosis and treatment response. More recently, NfL has been shown to facilitate individualized treatment decisions for individuals with MS. In this review, we discuss the characteristics that make NfL a highly informative biomarker and depict the available technologies used for its measurement. We further discuss the growing role of serum and CSF NfL in MS research and clinical settings. Finally, we address some of the current topics of debate regarding the use of NfL in clinical practice and examine the possible directions that this biomarker may take in the future.

Cerebrospinal Fluid Osteopontin and Inflammation-Associated Cytokines in Patients With Anti-N-Methyl-D-Aspartate Receptor Encephalitis

Anti-N-methyl-d-aspartate receptor (anti-NMDAR) encephalitis is an autoimmune neurological disorder. Osteopontin (OPN) is a secreted multifunctional phosphorylated glycoprotein that regulates various autoimmune and inflammatory diseases, but its diagnostic and prognostic values in anti-NMDAR encephalitis patients remain elusive. This retrospective study aimed to determine the levels of OPN and related cytokines in cerebrospinal fluid (CSF) of anti-NMDAR encephalitis patients and to assess their influence on disease severity so as to evaluate their efficacy as biomarkers for diagnosis and prognosis. CSF samples from 33 anti-NMDAR encephalitis, 13 viral encephalitis, and 21 controls were collected. All CSF were tested for levels of OPN and inflammation-associated cytokines [interleukin (IL)-6, IL-10, and tumor necrosis factor (TNF)-α] via ELISA. In addition, 15 anti-NMDAR encephalitis patients without follow-up relapse were re-examined for these four parameters 3 months later. The clinical status was evaluated by modified Rankin Scale (mRS) scores. Results showed that the CSF levels of these cytokines were increased in anti-NMDAR encephalitis patients compared to controls but not viral encephalitis patients. Their levels were decreased in remission compared with that in acute stage. Moreover, CSF OPN positively correlated with IL-6, white blood cell (WBC) counts, and C-reactive protein (CRP) levels in anti-NMDAR encephalitis patients. However, no associations were found between OPN or related cytokines and mRS scores in acute stage in anti-NMDAR encephalitis patients. Overall, CSF OPN and related cytokines were increased when anti-NMDAR encephalitis patients are in acute stage and decreased in remission, suggesting the underlying neuro-inflammatory process in this disease. However, they are not qualified with diagnostic or prognostic value.

The potential similarities of COVID-19 and autoimmune disease pathogenesis and therapeutic options: new insights approach

Cytokine pathways and their signaling disorders can be the cause of onset and pathogenesis of many diseases such as autoimmune diseases and COVID-19 infection. Autoimmune patients may be at higher risk of developing infection due to the impaired immune responses, the use of immunosuppressive drugs, and damage to various organs. Increased secretion of inflammatory cytokines and intolerance of the patient's immune system to COVID-19 infection are the leading causes of hospitalization of these patients. The content used in this paper has been taken from English language articles (2005-2020) retrieved from the PubMed database and Google Scholar search engine using "COVID-19," "Autoimmune disease," "Therapeutic," "Pathogenesis," and "Pathway" keywords. The emergence of COVID-19 and its association with autoimmune disorders is a major challenge in the management of these diseases. The results showed that the use of corticosteroids in the treatment of autoimmune diseases can make diagnosis and treatment of COVID-19 more challenging by preventing the fever. Due to the common pathogenesis of COVID-19 and autoimmune diseases, the use of autoimmune drugs as a possible treatment option could help control the virus. KEY POINTS: • Inflammatory cytokines play an essential role in the pathogenesis of COVID-19 • ACE2 dysfunctions are related to the with COVID-19 and autoimmune diseases • The use autoimmune diseases drugs can be useful in treating COVID-19.

Mast cells and angiogenesis in multiple sclerosis

Multiple sclerosis (MS) is an autoimmune disease, characterized by multiple demyelination of axons in both white and gray matter in the Central Nervous System (CNS). There is increasing evidence to support the notion that angiogenesis and chronic inflammation are mutually related. Different immune cells, including monocytes-macrophages, lymphocytes, neutrophils, mast cells (MCs) and dendritic cells are able to secrete an array of angiogenic cytokines, which promote growth, migration, and activation of endothelial cells. MCs play various roles in MS pathogenesis, influencing the innate immune response in peripheral tissues and in CNS. The aim of this review article is to discuss the role of MCs in MS pathogenesis with particular reference to the involvement of these inflammatory cells in the angiogenic processes occurring during MS.

Evaluation of plasma Osteopontin level in relapsing- remitting multiple sclerosis patients compared to healthy subjects in Isfahan Province

Background: Multiple sclerosis (MS) is known as a neuroinflammatory disease of the central nervous system (CNS). The neuroinflammation may induce pro-inflammatory cytokines such as Osteopontin (OPN). OPN plays an important role in the inflammation by modulating the T helper1 (Th1) and Th17 responses. Since the exact immune pathogenesis of MS is complex and not well defined and many factors are involved, the need to detect more contributing biomarkers may help in setting new therapeutic strategies.Objective: This study tried to compare plasma OPN levels in relapsing- remitting multiple sclerosis (RRMS) patients during the remission phase with healthy subjects in Isfahan province.Materials and methods: In a case-control study, plasma was collected from the 40 RRMS as well as 38 (age and sex matched) healthy individuals as a control group. PlasmaOPN level was measured and compared between the two groups by Enzyme-linked immunosorbent assays (ELISA).Result: Statistical analysis revealed that plasma OPN level was markedly higher in the case group (RRMS patients during the remission phase) compared with the control group (P- value = 0.039). Our results also showed that there was no statistically significant difference in mean of plasma OPN level among RRMS patients who were treated with interferon (IFN)-ß and those who were not (P- value = 0.332). There was also no correlation between OPN plasma level and EDSS score (r = 0.037, P- value = 0.835), age of onset (r = 0.161, P- value = 0.357) and duration of disease (r = 0.121, P- value = 0.490).Conclusion: Higher OPN plasma level in studied patients suggests that OPN increased in RRMS patients who were in remission phase. It could be hypothesized that plasma OPN level may be increased as part of the pro-inflammatory cytokine milieu taking place in MS patients. OPN may not be specific marker for MS, but targeting it might present promising therapeutic effect to MS patients.

An antibody-free sample pretreatment method for osteopontin combined with MALDI-TOF MS/MS analysis

Osteopontin is an osteoblast-secreted protein with an aspartic acid-rich, highly phosphorylated, and glycosylated structure. Osteopontin can easily bind to integrins, tumor cells, extracellular matrix and calcium, and is related to bone diseases, various cancers, inflammation etc. Here, DEAE-Cibacron blue 3GA was used to extract recombinant osteopontin from human plasma, and to deplete abundant plasma proteins with an antibody-free method. Using selected buffer systems, osteopontin and human serum albumin could be bound to DEAE-Cibacron blue 3GA, while immunoglobulin G was excluded. The bound osteopontin could then be separated from albumin by using different sequential elution buffers. By this method, 1 μg/mL recombinant osteopontin could be separated from the major part of the most abundant proteins in human plasma. After trypsin digestion, the extracted osteopontin could be successfully detected and identified by MALDI-TOF MS/MS using the m/z 1854.898 peptide and its fragments.

Biomarkers in Multiple Sclerosis

Multiple sclerosis (MS) is a chronic neurodegenerative autoimmune disease with a complex clinical course characterized by inflammation, demyelination, and axonal degeneration. Diagnosis of MS most commonly includes finding lesions in at least two separate areas of the central nervous system (CNS), including the brain, spinal cord, and optic nerves. In recent years, there has been a remarkable increase in the number of available treatments for MS. An optimal treatment is usually based on a personalized approach determined by an individual patient's prognosis and treatment risks. Biomarkers that can predict disability progression, monitor ongoing disease activity, and assess treatment response are integral in making important decisions regarding MS treatment. This review describes MS biomarkers that are currently being used in clinical practice; it also reviews and consolidates published findings from clinically relevant potential MS biomarkers in recent years. The work also discusses the challenges of validating and application of biomarkers in MS clinical practice.

Distinct Expression Patterns of Osteopontin and Dentin Matrix Protein 1 Genes in Pituitary Gonadotrophs

Cell-matrix interactions play important roles in pituitary development, physiology, and pathogenesis. In other tissues, a family of non-collagenous proteins, termed SIBLINGs, are known to contribute to cell-matrix interactions. Anterior pituitary gland expresses two SIBLING genes, Dmp1 (dentin matrix protein-1) and Spp1 (secreted phosphoprotein-1) encoding DMP1 and osteopontin proteins, respectively, but their expression pattern and roles in pituitary functions have not been clarified. Here we provide novel evidence supporting the conclusion that Spp1/osteopontin, like Dmp1/DMP1, are expressed in gonadotrophs in a sex- and age-specific manner. Other anterior pituitary cell types do not express these genes. In contrast to Dmp1, Spp1 expression is higher in males; in females, the expression reaches the peak during the diestrus phase of estrous cycle. In further contrast to Dmp1 and marker genes for gonadotrophs, the expression of Spp1 is not regulated by gonadotropin-releasing hormone in vivo and in vitro. However, Spp1 expression increases progressively after pituitary cell dispersion in both female and male cultures. We may speculate that gonadotrophs signal to other pituitary cell types about changes in the structure of pituitary cell-matrix network by osteopontin, a function consistent with the role of this secretory protein in postnatal tissue remodeling, extracellular matrix reorganization after injury, and tumorigenesis.

Raw cow's milk consumption and allergic diseases - The potential role of bioactive whey proteins

The prevalence of allergic diseases has increased significantly in Western countries in the last decades. This increase is often explained by the loss of rural living conditions and associated changes in diet and lifestyle. In line with this 'hygiene hypothesis', several epidemiological studies have shown that growing up on a farm lowers the risk of developing allergic diseases. The consumption of raw, unprocessed, cow's milk seems to be one of the factors contributing to this protective effect. Recent evidence indeed shows an inverse relation between raw cow's milk consumption and the development of asthma and allergies. However, the consumption of raw milk is not recommended due to the possible contamination with pathogens. Cow's milk used for commercial purposes is therefore processed, but this milk processing is shown to abolish the allergy-protective effects of raw milk. This emphasizes the importance of understanding the components and mechanisms underlying the allergy-protective capacity of raw cow's milk. Only then, ways to produce a safe and protective milk can be developed. Since mainly heat treatment is shown to abolish the allergy-protective effects of raw cow's milk, the heat-sensitive whey protein fraction of raw milk is an often-mentioned source of the protective components. In this review, several of these whey proteins, their potential contribution to the allergy-protective effects of raw cow's milk and the consequences of heat treatment will be discussed. A better understanding of these bioactive whey proteins might eventually contribute to the development of new nutritional approaches for allergy management.

Osteopontin plays a pivotal role in increasing severity of respiratory syncytial virus infection

The molecular mechanisms underlying susceptibility to severe respiratory syncytial virus (RSV) infection remain poorly understood. Herein, we report on the role of osteopontin (OPN) in regulation of RSV infection in human epithelial cells and how interleukin-1 beta (IL-1β), a cytokine secreted soon after RSV infection, when persistently expressed can induce OPN expression leading to increased viral infection. We first compared OPN expression in two human epithelial cell lines: HEK-293 and HEp-2. In contrast to HEp-2, HEK-293 expresses low levels of pro-caspase-1 resulting in decreased IL-1β expression in response to RSV infection. We found a correlation between low IL-1β levels and a delay in induction of OPN expression in RSV-infected HEK-293 cells compared to HEp-2. This phenomenon could partially explain the high susceptibility of HEp-2 cells to RSV infection versus the moderate susceptibility of HEK-293 cells. Also, HEK-293 cells expressing low levels of pro-caspase-1 exhibit decreased IL-1β expression and delayed OPN expression in response to RSV infection. HEK-293 cells incubated with human rIL-1β showed a dose-dependent increase in OPN expression upon RSV infection. Also, incubation with rOPN increased RSV viral load. Moreover, HEp-2 cells or mice infected with a mucogenic RSV strain RSV-L19F showed elevated levels of OPN in contrast to mice infected with the laboratory RSV strain rA2. This correlated with elevated levels of OPN following infection with RSV-L19F compared to rA2. Together, these results demonstrate that increased OPN expression is regulated in part by IL-1β, and the interplay between IL-1β and OPN signaling may play a pivotal role in the spread of RSV infection.

Neutralization of Osteopontin Ameliorates Acute Lung Injury Induced by Intestinal Ischemia-Reperfusion

Intestinal ischemia-reperfusion (I/R) is associated with acute respiratory distress syndrome. Osteopontin (OPN), a glycoprotein secreted from immune-reactive cells, plays a deleterious role in various inflammatory diseases. Considering OPN as a pro-inflammatory molecule, we hypothesize that the treatment with its neutralizing antibody (anti-OPN Ab) protects mice against intestinal I/R-induced acute lung injury (ALI). Intestinal I/R was induced in mice by superior mesenteric artery occlusion with a vascular clip. After 45 min of occlusion, the clip was removed and anti-OPN Ab (25 μg/mouse) or normal IgG isotype control (25 μg/mouse) was immediately administrated intravenously. Blood, small intestine, and lung tissues were collected at 4 h after reperfusion for various analyses. After intestinal I/R, mRNA and protein levels of OPN were significantly induced in the small intestine, lungs, and blood relative to sham-operated animals. Compared with the IgG control group, treatment of anti-OPN Ab significantly reduced plasma levels of pro-inflammatory cytokine and chemokine (IL-6 and MIP-2) and organ injury markers (AST, ALT, and LDH). The histological architecture of the gut and lung tissues in anti-OPN Ab-treated intestinal I/R-induced mice showed significant improvement versus the IgG control mice. The lung inflammation measured by the levels of IL-6, IL-1β, and MIP-2 was also significantly downregulated in the anti-OPN Ab-treated mice as compared with the IgG control mice. Besides, the lung MPO and neutrophil infiltration in anti-OPN Ab-treated mice showed significant reduction as compared with the IgG control animals. In conclusion, we have demonstrated beneficial outcomes of anti-OPN Ab treatment in protecting against ALI, implicating a novel therapeutic potential in intestinal I/R.

Osteopontin (OPN) as a CSF and blood biomarker for multiple sclerosis: A systematic review and meta-analysis

Identifying a reliable biomarker may accelerate diagnosis of multiple sclerosis (MS) and lead to early management of the disease. Accumulating evidence suggest that cerebrospinal fluid (CSF) and peripheral blood concentration of osteopontin (OPN) may have diagnostic and prognostic value in MS. We conducted a systematic review and meta-analysis of studies that measured peripheral blood and CSF levels of OPN in MS patients and controls to evaluate the diagnostic potential of this biomarker better. We searched PubMed, Web of Science and Scopus databases to find articles that measured OPN concentration in peripheral blood and CSF samples from MS patients up to October 19, 2016. Q statistic tests and the I2 index were applied for heterogeneity assessment. If the I2 index was less than 40%, the fixed-effects model was used for meta-analysis. Random-effects meta-analysis was chosen if the I2 value was greater than 40%. After removal of duplicates, 918 articles were identified, and 27 of them fulfilled the inclusion criteria. We included 22 eligible studies in the final meta-analysis. MS patients, in general, had considerably higher levels of OPN in their CSF and blood when compared to all types of controls (p<0.05). When the comparisons were made between different subtypes of MS patients and controls, the results pointed to significantly higher levels of OPN in CSF of MS subgroups (p<0.05). All subtypes of MS patients, except CIS patients, had increased blood levels of OPN compared to controls (p<0.05). In the second set of meta-analyses, we compared the peripheral blood and CSF concentrations of OPN between MS patient subtypes. CIS patients had significantly lower levels of OPN both in their peripheral blood and CSF compared to patients with progressive subtypes of MS (p<0.05). CSF concentration of OPN was significantly higher among RRMS patients compared to the CIS patients and SPMS patients (P<0.05). Finally, patients with active MS had significantly higher OPN levels in their CSF compared to patients with stable disease (P = 0.007). The result of this study confirms that increased levels of OPN exist in CSF and peripheral blood of MS patients and strengthens the evidence regarding the clinical utility of OPN as a promising and validated biomarker for MS.

Multiple sclerosis: genetics, biomarkers, treatments

PURPOSE OF REVIEW

We discuss new paradigms for understanding the immunopathology of multiple sclerosis through the recent development of high throughput genetic analysis, emergence of numerous candidate biomarkers, and the broadening of the treatment arsenal.

RECENT FINDINGS

The recent use of genome wide association studies provide new tools for a better understanding of multiple sclerosis etiology. Genome-wide association studies have identified many genes implicated in immune regulation and the next step will be to elucidate how those genetic variations influence immune cell function to drive disease development and progression. Furthermore, patient care has seen the emergence of new biomarkers for monitoring disease progression and response to treatment. Finally, the introduction of numerous immunomodulatory treatments will likely improve clinical outcome of multiple sclerosis patients in the future.

SUMMARY

Breakthroughs in the field of multiple sclerosis have led to a better understanding of the physiopathology of the disease, follow up, and treatment of the patients that develop relapsing remitting multiple sclerosis. The next challenge for multiple sclerosis will be to press forward to model and decipher multiple sclerosis progression, which will help both to develop therapeutics and generate knowledge about mechanisms of neurodegeneration.

Fluid biomarker and electrophysiological outcome measures for progressive MS trials

Progressive multiple sclerosis (MS) is characterized by insidious clinical worsening that is difficult to accurately quantify and predict. Biofluid markers and electrophysiological measures are potential candidate outcome measures in clinical trials, allowing the quantification of nervous damage occurring in the disease. Neurofilaments are highly specific neuronal proteins. They may have come closest to such applications by their higher concentrations repeatedly demonstrated in cerebrospinal fluid (CSF) in all stages of MS, during relapses, their responsiveness to disease-modifying treatments in relapsing and progressive MS and their associations with measures of inflammatory and degenerative magnetic resonance imaging (MRI) outcomes. Digital single-molecule array (Simoa) technology improves accuracy of bioassays in the quantification of neurofilament light chain (NfL) in serum and plasma. NfL seems to mark a common final path of neuroaxonal injury independent of specific causal pathways. CSF and blood levels of NfL are highly correlated across various diseases including MS, suggesting that blood measurements may be useful in assessing response to treatment and predicting future disease activity. Other biomarkers like matrix metalloproteinases, chemokines, or neurotrophic factors have not been studied to a similar extent. Such measures, especially in blood, need further validation to enter the trial arena or clinical practice. The broadening armamentarium of highly sensitive assay technologies in the future may shed even more light on patient heterogeneity and mechanisms leading to disability in MS. Evoked potentials (EPs) are used in clinical practice to measure central conduction of central sensorimotor pathways. They correlate with and predict the severity of clinical involvement of their corresponding function. Their validation for use in multicenter studies is still lacking, with the exception of visual EPs. If further validated, EPs and fluid biomarkers would represent useful outcome measures for clinical trials, being related to specific mechanisms of the ongoing pathologic changes.

Science is 1% inspiration and 99% biomarkers

Neurodegeneration plays a key role in multiple sclerosis (MS) contributing to long-term disability in patients. The prognosis is, however, unpredictable coloured by complex disease mechanisms which can only be clearly appreciated using biomarkers specific to pathobiology of the underlying process. Here, we describe six promising neurodegenerative biomarkers in MS (neurofilament proteins, neurofilament antibodies, tau, N-acetylaspartate, chitinase and chitinase-like proteins and osteopontin), critically evaluating the evidence using a modified Bradford Hill criteria.

Role of Anti-Osteopontin Antibodies in Multiple Sclerosis and Experimental Autoimmune Encephalomyelitis

Osteopontin (OPN) is highly expressed in demyelinating lesions in multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE). OPN is cleaved by thrombin into N- (OPN-N) and C-terminal (OPN-C) fragments with different ligands and functions. In EAE, administering recombinant OPN induces relapses, whereas treatment with anti-OPN antibodies ameliorates the disease. Anti-OPN autoantibodies (autoAbs) are spontaneously produced during EAE but have never been detected in MS. The aim of the study was to evaluate anti-OPN autoAbs in the serum of MS patients, correlate them with disease course, and recapitulate the human findings in EAE. We performed ELISA in the serum of 122 patients collected cross-sectionally, and 50 patients with relapsing–remitting (RR) disease collected at diagnosis and followed longitudinally for 10 years. In the cross-sectional patients, the autoAb levels were higher in the RR patients than in the primary- and secondary-progressive MS and healthy control groups, and they were highest in the initial stages of the disease. In the longitudinal group, the levels at diagnosis directly correlated with the number of relapses during the following 10 years. Moreover, in patients with active disease, who underwent disease-modifying treatments, autoAbs were higher than in untreated patients and were associated with low MS severity score. The autoAb displayed neutralizing activity and mainly recognized OPN-C rather than OPN-N. To confirm the clinical effect of these autoAbs in vivo, EAE was induced using myelin oligodendrocyte glycoprotein MOG_35–55 in C57BL/6 mice pre-vaccinated with ovalbumin (OVA)-linked OPN or OVA alone. We then evaluated the titer of antibodies to OPN, the clinical scores and in vitro cytokine secretion by spleen lymphocytes. Vaccination significantly induced antibodies against OPN during EAE, decreased disease severity, and the protective effect was correlated with decreased T cell secretion of interleukin 17 and interferon-γ ex vivo. The best effect was obtained with OPN-C, which induced significantly faster and more complete remission than other OPN vaccines. In conclusion, these data suggest that production of anti-OPN autoAbs may favor remission in both MS and EAE. Novel strategies boosting their levels, such as vaccination or passive immunization, may be proposed as a future strategy in personalized MS therapy.

Extracellular proteasome-osteopontin circuit regulates cell migration with implications in multiple sclerosis

Osteopontin is a pleiotropic cytokine that is involved in several diseases including multiple sclerosis. Secreted osteopontin is cleaved by few known proteases, modulating its pro-inflammatory activities. Here we show by in vitro experiments that secreted osteopontin can be processed by extracellular proteasomes, thereby producing fragments with novel chemotactic activity. Furthermore, osteopontin reduces the release of proteasomes in the extracellular space. The latter phenomenon seems to occur in vivo in multiple sclerosis, where it reflects the remission/relapse alternation. The extracellular proteasome-mediated inflammatory pathway may represent a general mechanism to control inflammation in inflammatory diseases.

The association between osteopontin gene polymorphisms, osteopontin expression and sarcoidosis

Background

Sarcoidosis is a systemic inflammatory disease of unknown etiology. Osteopontin (SPP1, OPN) is an extra cellular matrix glycoprotein and cytokine with a known role in granuloma formation and in autoimmune and inflammatory diseases.

Objective

To determine whether plasma OPN levels are elevated in patients with sarcoidosis and compare the frequency of four single nucleotide polymorphism (SNPs) variants in the OPN gene in sarcoidosis patients compared to healthy controls.

Methods

Demographic and clinical information, radiological studies and pulmonary function tests were evaluated in 113 patients with sarcoidosis and in 79 healthy controls. Blood samples were analyzed for SNPs of the OPN gene and for plasma OPN and CRP levels. Association between clinical features of disease and OPN levels as well as SNP frequencies was determined.

Results

Plasma OPN levels were higher in sarcoidosis patients than in healthy subjects, (median: 217 vs 122ng/ml, p<0.001). Area under the curve for receiver operator curves (ROC) was 0.798 (0.686–0.909 95% CI.) No differences were observed between sarcoidosis patients and controls in the frequency of any of the SNPs evaluated. Presence of lung parenchymal involvement was associated with SNP distribution at rs1126772 (p = 0.02). We found no correlation between SNPs distribution and plasma OPN levels.

Conclusions

Osteopontin protein levels are elevated in sarcoidosis. We found no evidence for an association between SNPs on the osteopontin gene and plasma OPN levels or the presence of sarcoidosis, however, an association between genotype and several phenotypic clinical parameters of disease was observed.