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Background and ObjectivesFluid biomarkers are a recent field of interest in Huntington disease (HD). We focused on small circulating RNAs from plasma of subjects with prodromal (pre-HD) and overt disease by a two-stage approach: an unbiased investigation by an array method and a validation study to quantify a significant small nucleolar RNA.MethodsThrough Affymetrix Gene-Chip-miRNA-Array we performed an exploratory study on 9 HD patients, 8 healthy subjects (HS) and 5 psychiatric patients (PP; who share drugs with HD patients, to control for iatrogenic effects). Through real time PCR we validated the results in an independent population of 24 HD patients, 15 pre-HD, 24 PP, 28 Alzheimer’s disease (AD) patients (added to control the disease-specificity of our finding) and 23 HS. A bioinformatic analysis was also performed to interpret our finding.ResultsThe microarray results showed a significant signal for U13 small nucleolar RNA (SNORD13) that was increased in plasma of HD patients compared to controls (fold change, 1.54, p =0.003 HD vs. HS, and fold change 1.44 p = 0.0026 HD vs. PP). In the validation population the significant increase in HD patients was evident compared to both pre-HD and the three control groups (pDiscussionWe report the unprecedented finding of a potential role of small nucleolar RNAs in HD. Circulating SNORD13 seems a good biomarker for clinical purposes. It seems to be specific for HD and to peripherally report a plausible ‘tipping point’ in the pathogenic cascade at neuronal level, possibly paving the way for new therapeutic targets.

Background: MS is a chronic inflammatory disease of the CNS leading to demyelination and neurodegeneration, with a complex and still to be clarified aetiology. Several data, coming from patients' samples and from animal models, show that Oxidative Status (OS) plays an important role in MS pathogenesis. Overproduction of reactive oxidative species by macrophages/microglia can bring about cellular injury and ensuing cell death by oxidizing cardinal cellular components. Oxidized molecules are present in active MS lesions and are associated with neurodegeneration. Methods: We undertook a structured search of bibliographic databases for peer-reviewed research literature focusing on OS in MS. The contents of the selected papers were described in the context of a conceptual framework. A special emphasis was given to the results of our study in the field. Results: The results of our three recent studies were put in the context and discussed taking into account the literature on the topic. Oxidative damage underpinned an imbalance shared by MS and neurodegenerative diseases such as Alzheimer and Parkinson diseases. In people with clinically isolated syndrome (an early phase of MS) oxidative stress proved to contribute to disease pathophysiology and to provide biomarkers that may help predict disease evolution. A drug screening platform based on multiple assays to test the remyelinating potential of library of approved compounds showed two anti-oxidants, edaravone and 5-methyl-7- methoxyisoflavone, as active drugs. Moreover, an analysis of 'structure activity relationship' showed off-targets sites of these compounds that accounted for their remyelinating activity, irrespective of their antioxidant action. Conclusion: Overall, edaravone emerges as a candidate to treat complex disease such as MS, where inflammation, oxidative stress and neurodegeneration contribute to disease progression, together or individually, in different phases and disease types. Furthermore, approaches based on drug repositioning seem to maintain the promise of helping discover novel treatment for complex diseases, where molecular targets are largely unknown.

Plasma small RNAs have been recently explored as biomarkers in Huntington’s disease (HD). We performed an exploratory study on nine HD patients, eight healthy subjects (HS), and five psychiatric patients (PP; to control for iatrogenic confounder effects) through an Affymetrix-Gene-Chip-miRNA-Array. We validated the results in an independent population of 23 HD, 15 pre-HD, 24 PP, 28 Alzheimer’s disease (AD) patients (to control the disease-specificity) and 22 HS through real-time PCR. The microarray results showed higher levels of U13 small nucleolar RNA (SNORD13) in HD patients than controls (fold change 1.54, p = 0.003 HD vs. HS, and 1.44, p = 0.0026 HD vs. PP). In the validation population, a significant increase emerged with respect to both pre-HD and the control groups (p < 0.0001). SNORD13 correlated with the status of the mutant huntingtin carrier (r = 0.73; p < 0.001) and the disease duration (r = 0.59; p = 0.003). The receiver operating characteristic (ROC) curve analysis showed the high accuracy of SNORD13 in discriminating HD patients from other groups (AUC = 0.963). An interactome and pathway analysis on SNORD13 revealed enrichments for factors relevant to HD pathogenesis. We report the unprecedented finding of a potential disease-specific role of SNORD13 in HD. It seems to peripherally report a ‘tipping point’ in the pathogenic cascade at the neuronal level.

SUMMARYWe exploited genetic information to assess non-genetic influences in autoimmunity. We isolated gene modules whose products physically interact with environmental exposures related to autoimmunity, and analyzed their nominal statistical evidence of association with autoimmune and non-autoimmune diseases in genome-wide association studies (GWAS) data. Epstein Barr virus (EBV) and other Herpesviruses interactomes emerged as specifically associated with multiple sclerosis (MS), possibly under common regulatory mechanisms. Analyses of MS blood and brain transcriptomes, cytofluorimetric studies of endogenous EBV-infected lymphoblastoid lines, and lesion immunohistochemistry, confirmed a dysregulation of MS-associated EBV interactors, suggesting their contribution to CD40 signaling alterations in MS. These interactors resulted enriched in modules from inherited axonopathies-causing genes, supporting a link between EBV and neurodegeneration in MS, in accord with the observed transcriptomic dysregulations in MS brains. They were also enriched with top-ranked pharmaceutical targets prioritized on a genetic basis. This study delineates a disease-specific influence of herpesviruses on MS biology.

The functions of mucosal-associated invariant T (MAIT) cells in homeostatic conditions include the interaction with the microbiota and its products, the protection of body barriers, and the mounting of a tissue-repair response to injuries or infections. Dysfunction of MAIT cells and dysbiosis occur in common chronic diseases of inflammatory, metabolic, and tumor nature. This review is aimed at analyzing the changes of MAIT cells, as well as of the microbiota, in multiple sclerosis and other autoimmune disorders. Common features of dysbiosis in these conditions are the reduced richness of microbial species and the unbalance between pro-inflammatory and immune regulatory components of the gut microbiota. The literature concerning MAIT cells in these disorders is rather complex, and sometimes not consistent. In multiple sclerosis and other autoimmune conditions, several studies have been done, or are in progress, to find correlations between intestinal permeability, dysbiosis, MAIT cell responses, and clinical biomarkers in treated and treatment-naïve patients. The final aims are to explain what activates MAIT cells in diseases not primarily infective, which interactions with the microbiota are potentially pathogenic, and their dynamics related to disease course and disease-modifying treatments.

A clinically actionable understanding of multiple sclerosis (MS) etiology goes through GWAS interpretation, prompting research on new gene regulatory models. We previously suggested a stochastic etiologic model where small-scale random perturbations could reach a threshold for MS development. The recently described mapping of the transient transcriptome (TT), including intergenic and intronic RNAs, seems appropriate to verify this model through a rigorous colocalization analysis. We show that genomic regions coding for the TT were significantly enriched for MS-associated GWAS variants and DNA binding sites for molecular transducers mediating putative, non-genetic, etiopathogenetic factors for MS (e.g., vitamin D deficiency, Epstein Barr virus latent infection, B cell dysfunction). These results suggest a model whereby TT-coding regions are hotspots of convergence between genetic ad non-genetic factors of risk/protection for MS, and plausibly for other complex disorders. Our colocalization analysis also provides a freely available data resource (www.mscoloc.com) for future research on MS transcriptional regulation.

Genome-wide association studies have identified more than 200 multiple sclerosis (MS)-associated loci across the human genome over the last decade, suggesting complexity in the disease etiology. This complexity poses at least two challenges: the definition of an etiological model including the impact of nongenetic factors, and the clinical translation of genomic data that may be drivers for new druggable targets. We reviewed studies dealing with single genes of interest, to understand how MS-associated single nucleotide polymorphism (SNP) variants affect the expression and the function of those genes. We then surveyed studies on the bioinformatic reworking of genome-wide association studies (GWAS) data, with aggregate analyses of many GWAS loci, each contributing with a small effect to the overall disease predisposition. These investigations uncovered new information, especially when combined with nongenetic factors having possible roles in the disease etiology. In this context, the interactome approach, defined as “modules of genes whose products are known to physically interact with environmental or human factors with plausible relevance for MS pathogenesis”, will be reported in detail. For a future perspective, a polygenic risk score, defined as a cumulative risk derived from aggregating the contributions of many DNA variants associated with a complex trait, may be integrated with data on environmental factors affecting the disease risk or protection.

Background: Severe coronavirus disease 2019 (COVID-19) is associated with multiple comorbidities and is characterized by an auto-aggressive inflammatory state leading to massive collateral damage. To identify preventive and therapeutic strategies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), it is important to ascertain the molecular interactions between virus and host, and how they translate into disease pathophysiology. Methods: We matched virus-human protein interactions of human coronaviruses and other respiratory viruses with lists of genes associated with autoimmune diseases and comorbidities associated to worse COVID-19 course. We then selected the genes included in the statistically significant intersection between SARS-CoV-2 network and disease associated gene sets, identifying a meta-interactome. We analyzed the meta-interactome genes expression in samples derived from lungs of infected humans, and their regulation by IFN-β. Finally, we performed a drug repurposing screening to target the network’s most critical nodes. Results: We found a significant enrichment of SARS-CoV-2 interactors in immunological pathways and a strong association with autoimmunity and three prognostically relevant conditions (type 2 diabetes, coronary artery diseases, asthma), that present more independent physiopathological subnetworks. We observed a reduced expression of meta-interactome genes in human lungs after SARS-CoV-2 infection, and a regulatory potential of type I interferons. We also underscored multiple repurposable drugs to tailor the therapeutic strategies. Conclusions: Our data underscored a plausible genetic background that may contribute to the distinct observed pathophysiologies of severe COVID-19. Also, these results may help identify the most promising therapeutic targets and treatments for this condition.

Background: B cells are key pathogenic effectors in multiple sclerosis (MS) and several therapies have been designed to restrain B cell abnormalities by directly targeting this lymphocyte population. Objectives: Moving from our data showing a Toll-like receptor (TLR)7-driven dysregulation of B cell response in relapsing–remitting multiple sclerosis (RRMS) and having found a low serum level of Thymosin-α1 (Tα1) in patients, we investigated whether the addition of this molecule to peripheral blood mononuclear cells (PBMCs) would influence the expansion of regulatory B cell subsets, known to dampen autoimmune inflammation. Methods: Serum Tα1 level was measured by enzyme immunoassay. Cytokine expression was evaluated by Cytometric Bead Array (CBA), enzyme-linked immunosorbent assay (ELISA), and real-time reverse transcription polymerase chain reaction (RT-PCR). B cell subsets were analyzed by flow cytometry. Results: Tα1 pre-treatment induces an anti-inflammatory status in TLR7-stimulated RRMS PBMC cultures, reducing the secretion of pro-inflammatory interleukin (IL)-6, IL-8, and IL-1β while significantly increasing the regulatory IL-10 and IL-35. Indeed, Tα1 treatment enhanced expansion of CD19+CD24+CD38hi transitional-immature and CD24low/negCD38hi plasmablast-like regulatory B cell subsets, which likely inhibit both interferon (IFN)-γ and IL-17 production. Conclusion:: Our study reveals a deficient ability of B cells from MS patients to differentiate into regulatory subsets and unveils a novel anti-inflammatory and repurposing potential for Tα1 in MS targeting B cell response.

SUMMARYWe exploited genetic information to assess the role of non-genetic factors in multifactorial diseases. To this aim we isolated candidate “interactomes” (i.e. groups of genes whose products are known to physically interact with environmental exposures and biological processes, plausibly relevant for disease pathogenesis) and analyzed nominal statistical evidence of association with genetic predisposition to multiple sclerosis (MS) and other inflammatory and non-inflammatory complex disorders. The interaction between genotype and Herpesviruses emerged as specific for MS, with Epstein Barr virus (EBV) showing higher levels of significance compared to Human Herpesvirus 8 (HHV8) and, more evidently, to cytomegalovirus (CMV). In accord with this result, when we classified the MS-associated genes contained in the interactomes into canonical pathways, the analysis converged towards biological functions of B cells, in particular the CD40 pathway. When we analyzed peripheral blood transcriptomes in persons with MS, we found a significant dysregulation of MS-associated genes belonging to the EBV interactome in primary progressive MS. This study indicates that the interaction between herpesviruses and predisposing genetic background is of causal significance in MS, and provides a mechanistic explanation for the long-recognized association between EBV and this condition.

Alteration in endogenous Interferon (IFN) system may profoundly impact immune cell function in autoimmune diseases. Here, we provide evidence that dysregulation in IFN-regulated genes and pathways are involved in B cell- and monocyte-driven pathogenic contribution to Multiple Sclerosis (MS) development and maintenance. In particular, by using an Interferome-based cell type-specific approach, we characterized an increased susceptibility to an IFN-linked caspase-3 dependent apoptotic cell death in both B cells and monocytes of MS patients that may arise from their chronic activation and persistent stimulation by activated T cells. Ongoing caspase-3 activation functionally impacts on MS monocyte properties influencing the STAT-3/IL-16 axis, thus, driving increased expression and massive release of the bio-active IL-16 triggering and perpetuating CD4+ T cell migration. Importantly, our analysis also identified a previously unknown multi-component defect in type I IFN-mediated signaling and response to virus pathways specific of MS B cells, impacting on induction of anti-viral responses and Epstein-barr virus infection control in patients. Taking advantage of cell type-specific transcriptomics and in-depth functional validation, this study revealed pathogenic contribution of endogenous IFN signaling and IFN-regulated cell processes to MS pathogenesis with implications on fate and functions of B cells and monocytes that may hold therapeutic potential.

Multiple sclerosis is a complex, multifactorial, dysimmune disease prevalent in women. Its etiopathogenesis is extremely intricate, since each risk factor behaves as a variable that is interconnected with others. In order to understand these interactions, sex must be considered as a determining element, either in a protective or pathological sense, and not as one of many variables. In particular, sex seems to highly influence immune response at chromosomal, epigenetic, and hormonal levels. Environmental and genetic risk factors cannot be considered without sex, since sex-based immunological differences deeply affect disease onset, course, and prognosis. Understanding the mechanisms underlying sex-based differences is necessary in order to develop a more effective and personalized therapeutic approach.

Growing evidences put B lymphocytes on a central stage in multiple sclerosis (MS) immunopathology. While investigating the effects of interferon-β (IFN-β) therapy, one of the most used first-line disease-modifying drugs for the treatment of relapsing-remitting MS, in circulating B-cell sub-populations, we found a specific and marked decrease of CD27+ memory B cells. Interestingly, memory B cells are considered a population with a great disease-driving relevance in MS and resulted to be also target of B-cell depleting therapies. In addition, Epstein-Barr virus (EBV), associated with MS etiopathogenesis, harbors in this cell type and an IFN-β-induced reduction of the memory B-cell compartment, in turn, resulted in a decreased expression of the EBV gene latent membrane protein 2A in treated patients. We found that in vivo IFN-β therapy specifically and highly induced apoptosis in memory B cells, in accordance with a strong increase of the apoptotic markers Annexin-V and active caspase-3, via a mechanism requiring the FAS-receptor/TACI (transmembrane activator and CAML interactor) signaling. Thus, efficacy of IFN-β therapy in MS may rely not only on its recognized anti-inflammatory activities but also on the specific depletion of memory B cells, considered to be a pathogenic cell subset, reducing their inflammatory impact in target organs.

Easily accessible biomarkers in Huntington disease (HD) are actively searched. We investigated telomere length and DNA double-strand breaks (histone variant pγ-H2AX) as predictive disease biomarkers in peripheral blood mononuclear cells (PBMC) from 25 premanifest subjects, 58 HD patients with similar CAG expansion in the huntingtin gene (HTT), and 44 healthy controls (HC). PBMC from the pre-HD and HD groups showed shorter telomeres (p < 0.0001) and a significant increase of pγ-H2AX compared to the controls (p < 0.0001). The levels of pγ-H2AX correlated robustly with the presence of the mutated gene in pre-HD and HD. The availability of a potentially reversible biomarker (pγ-H2AX) in the premanifest stage of HD, negligible in HC, provides a novel tool to monitor premanifest subjects and find patient-specific drugs. Ann Neurol 2018;00:1-6 ANN NEUROL 2019;85:296-301.

Multiple sclerosis (MS) witnessed relevant therapeutic progress in the last decade. This notwithstanding, safety, quality of life, and overtreatment remain elements of strong concern for patients. Safe and manageable therapies that can be used upon the (biological) onset of the disease, without risk of overtreatment, are important unmet needs in MS. Bacille Calmette-Guerin (BCG) vaccine may have these characteristics because it has beneficial results in early MS and its first demyelinating episodes. Safe, cheap, and handy, BCG vaccine seems appropriate as a frontline immunomodulatory approach for people with radiologically isolated syndromes (RIS; that is, a magnetic resonance imaging of the brain compatible with MS, without any symptom or sign of disease). A trial underway in RIS patients will contribute to verification of this hypothesis. Another promising field for adjuvant approach seems to be that of common disorders, such as Alzheimer’s and Parkinson’s disease, classically considered of neurodegenerative nature. Recent evidence consistently showed that neuroinflammation is a significant component underlying these neurological diseases, and BCG vaccine fosters immunoregulatory circuit and tissue repair in experimental models.

Several evidences emphasize B-cell pathogenic roles in multiple sclerosis (MS). We performed transcriptome analyses on peripheral B cells from therapy-free patients and age/sex-matched controls. Down-regulation of two transcripts (interferon response factor 1-IRF1, and C-X-C motif chemokine 10-CXCL10), belonging to the same pathway, was validated by RT-PCR in 26 patients and 21 controls. IRF1 and CXCL10 transcripts share potential seeding sequences for hsa-miR-424, that resulted up-regulated in MS patients. We confirmed this interaction and its functional effect by transfection experiments. Consistent findings indicate down-regulation of IRF1/CXCL10 axis, that may plausibly contribute to a pro-survival status of B cells in MS.

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Background: Blood biomarkers, that may improve the management of the pre−manifest phase of Huntington's disease (PRE−HD), are actively searched. We investigated telomere length (TL) and DNA damage signatures (DDS) as potential predictive biomarkers in peripheral blood mononuclear cells (PBMC) of PRE−HD and HD patients. Methods: We analysed the DNA isolated from fresh PBMC of 58 HD and 23 PRE−HD subjects with similar CAG expansion in the huntingtin (HTT) gene (44·20±2·85, 43·55±2·70; mean±SD) and 44 healthy controls (HC). We measured the TL by qPCR and double−strand DNA breaks by flow cytometric analysis of phosphorylated γ−H2AX (pγ−H2AX). Findings: PBMC from PRE−HD and HD groups showed shorter telomeres (p

C-Glucoside derivatives covalently linked to the arsenic atom in different oxidation states have been synthesized by avoiding protection-deprotection steps. While compound 1, bearing an AsV atom, did not show any significant biological activity, compound 2, in which the glucose moiety is linked to the arsenic atom as dithioarsenical (AsIII), showed promising antiproliferative activity on a cell line of neuroblastoma (SK-N-BE).

Objective: We analyzed the Epstein-Barr nuclear antigen 2 ( EBNA2 ) gene, which contains the most variable region of the viral genome, in persons with multiple sclerosis (MS) and control subjects to verify whether virus genetic variants are involved in disease development. Methods: A seminested PCR approach and Sanger sequencing were used to analyze EBNA2 in 53 patients and 38 matched healthy donors (HDs). High-throughput sequencing by Illumina MiSeq was also applied in a subgroup of donors (17 patients and 17 HDs). Patients underwent gadolinium-enhanced MRI and human leucocyte antigen typing. Results: MS risk significantly correlated with an excess of 1.2 allele (odds ratio [OR] = 5.13; 95% confidence interval [CI] 1.84–14.32; p = 0.016) and underrepresentation of 1.3B allele (OR = 0.23; 95% CI 0.08–0.51; p = 0.0006). We identified new genetic variants, mostly 1.2 allele- and MS-associated (especially amino acid variation at position 245; OR = 9.4; 95% CI 1.19–78.72; p = 0.0123). In all cases, the consensus sequence from deep sequencing confirmed Sanger sequencing (including the cosegregation of newly identified variants with known EBNA2 alleles) and showed that the extent of genotype intraindividual variability was higher than expected: rare EBNA2 variants were detected in all HDs and patients with MS (range 1–17 and 3–19, respectively). EBNA2 variants did not seem to correlate with human leucocyte antigen typing or clinical/MRI features. Conclusions: Our study unveils a strong association between Epstein-Barr virus genomic variants and MS, reinforcing the idea that Epstein-Barr virus contributes to disease development.

Changes of intestinal permeability (IP) have been extensively investigated in inflammatory bowel diseases (IBD) and celiac disease (CD), underpinned by a known unbalance between microbiota, IP and immune responses in the gut. Recently the influence of IP on brain function has greatly been appreciated. Previous works showed an increased IP that preceded experimental autoimmune encephalomyelitis development and worsened during disease with disruption of TJ. Moreover, studying co-morbidity between Crohn's disease and MS, a report described increased IP in a minority of cases with MS. In a recent work we found that an alteration of IP is a relatively frequent event in relapsing-remitting MS, with a possible genetic influence on the determinants of IP changes (as inferable from data on twins); IP changes included a deficit of the active mechanism of absorption from intestinal lumen. The results led us to hypothesize that gut may contribute to the development of MS, as suggested by another previous work of our group: a population of CD8+CD161high T cells, belonging to the mucosal-associated invariant T (MAIT) cells, a gut- and liver-homing subset, proved to be of relevance for MS pathogenesis. We eventually suggest future lines of research on IP in MS: studies on IP changes in patients under first-line oral drugs may result useful to improve their therapeutic index; correlating IP and microbiota changes, or IP and blood-brain barrier changes may help clarify disease pathogenesis; exploiting the IP data to disclose co-morbidities in MS, especially with CD and IBD, may be important for patient care.

There is no treatment for the myelin loss in multiple sclerosis, ultimately resulting in the axonal degeneration that leads to the progressive phase of the disease. We established a multi-tiered platform for the sequential screening of drugs that could be repurposed as remyelinating agents. We screened a library of 2,000 compounds (mainly Food and Drug Administration (FDA)-approved compounds and natural products) for cellular metabolic activity on mouse oligodendrocyte precursors (OPC), identifying 42 molecules with significant stimulating effects. We then characterized the effects of these compounds on OPC proliferation and differentiation in mouse glial cultures, and on myelination and remyelination in organotypic cultures. Three molecules, edaravone, 5-methyl-7-methoxyisoflavone and lovastatin, gave positive results in all screening tiers. We validated the results by retesting independent stocks of the compounds, analyzing their purity, and performing dose-response curves. To identify the chemical features that may be modified to enhance the compounds’ activity, we tested chemical analogs and identified, for edaravone, the functional groups that may be essential for its activity. Among the selected remyelinating candidates, edaravone appears to be of strong interest, also considering that this drug has been approved as a neuroprotective agent for acute ischemic stroke and amyotrophic lateral sclerosis in Japan.

Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system (CNS) leading to demyelination and neurodegeneration. It is believed to be caused by the interaction between genetic susceptibility and environmental factors. Evidence from several epidemiological and clinical studies suggested that changes in metal levels and oxidative status may contribute to the development of various neurological diseases, including MS. Many studies have been conducted to evaluate the mechanisms by which the metals induce neuroinflammation and neurotoxicity. Here, we review the literature regarding the role of metals with supposed pathogenic relevance in MS. We also discuss the results of our previous studies showing chemical elements and oxidative status imbalance in the serum of patients with MS and other neurodegenerative diseases, as well as in people with clinically isolated syndrome (CIS, considered an early phase of MS). Descriptive statistics revealed numerous differences between each disease and healthy status. A concordant imbalance (reduction in Fe, Zn, and serum antioxidant capacity, and increase in serum oxidative status) was shared by Alzheimer’s disease, Parkinson’s disease, and MS. The peculiar imbalance in serum elements and oxidative status that characterizes CIS people may predict conversion to clinically definite MS.

The implication of B lymphocytes in the immunopathology of multiple sclerosis (MS) is increasingly recognized. Here we investigated the response of B cells to IFN-β, a first-line therapy for relapsing-remitting MS patients, upon stimulation with TLR. IFN-β restored the frequency of TLR7-induced IgM and IgG-secreting cells in MS patients to the levels found in healthy donors, showing a specific deficiency in the TLR7 pathway. However, no difference was observed in the TLR9 response. Furthermore, in MS-derived PBMCs, TLR7-mediated production of IL-6 and the ex vivo expression of B-cell-activating factor of the TNF family, two crucial cytokines for B-cell differentiation and survival, were induced by IFN-β. Depletion of monocytes, which are key producers of both IL-6 and B-cell-activating factor of the TNF family, showed that TLR7-mediated B-cell differentiation into Ig-secreting cells is strongly dependent on the cross-talk between B cells and monocytes. Accordingly, impaired expression of TLR7 mRNA was observed in PBMCs and monocytes isolated from MS-affected individuals as compared with those from healthy donors, which was rescued by IFN-β therapy. Collectively, our data unveil a novel TLR7-regulated mechanism in in vivo IFN-β-stimulated whole leukocytes that could be exploited to define new TLR7-based strategies for the treatment of MS.

Here we have collected evidence suggesting that chronic changes in the NO homeostasis and the rise of reactive oxygen species bioavailability can contribute to cell dysfunction in Leber’s hereditary optic neuropathy (LHON) patients. We report that peripheral blood mononuclear cells (PBMCs), derived from a female LHON patient with bilateral reduced vision and carrying the pathogenic mutation 11778/ND4, display increased levels of reactive oxygen species (ROS) and reactive nitrogen species (RNS), as revealed by flow cytometry, fluorometric measurements of nitrite/nitrate, and 3-nitrotyrosine immunodetection. Moreover, viability assays with the tetrazolium dye MTT showed that lymphoblasts from the same patient are more sensitive to prolonged NO exposure, leading to cell death. Taken together these findings suggest that oxidative and nitrosative stress cooperatively play an important role in driving LHON pathology when excess NO remains available over time in the cell environment.

Epstein-Barr virus (EBV) latently infects the majority of the human population and is implicated as a causal or contributory factor in numerous diseases. We sequenced 27 complete EBV genomes from a cohort of Multiple Sclerosis (MS) patients and healthy controls from Italy, although no variants showed a statistically significant association with MS. Taking advantage of the availability of ∼130 EBV genomes with known geographical origins, we reveal a striking geographic distribution of EBV sub-populations with distinct allele frequency distributions. We discuss mechanisms that potentially explain these observations, and their implications for understanding the association of EBV with human disease.

Background: Peptidylarginine deiminase 2 (PAD2) and peptidylarginine deiminase 4 (PAD4) are two members of PAD family which are over-expressed in the multiple sclerosis (MS) brain. Through its enzymatic activity PAD2 converts myelin basic protein (MBP) arginines into citrullines – an event that may favour autoimmunity – while peptidylarginine deiminase 4 (PAD4) is involved in chromatin remodelling. Objectives: Our aim was to verify whether an altered epigenetic control of PAD2, as already shown in the MS brain, can be observed in peripheral blood mononuclear cells (PBMCs) of patients with MS since some of these cells also synthesize MBP. Methods: The expression of most suitable reference genes and of PAD2 and PAD4 was assessed by qPCR. Analysis of DNA methylation was performed by bisulfite method. Results: The comparison of PAD2 expression level in PBMCs from patients with MS vs. healthy donors showed that, as well as in the white matter of MS patients, the enzyme is significantly upregulated in affected subjects. Methylation pattern analysis of a CpG island located in the PAD2 promoter showed that over-expression is associated with promoter demethylation. Conclusion: Defective regulation of PAD2 in the periphery, without the immunological shelter of the blood–brain barrier, may contribute to the development of the autoimmune responses in MS.