Acute versus chronic inflammatory markers and cognition in older black adults: Results from the Minority Aging Research Study.

Peripheral inflammation is elevated in older Black adults, an elevation which prior work has suggested may be due to chronic stress associated with systemic racism and related adverse cardiovascular health conditions. Inflammation is also involved in the pathogenic processes of dementia; however, limited (and mixed) results exist concerning inflammation and cognitive decline in Black adults. We characterized patterns of inflammation and their role in cognitive decline in 280 older Black adults (age = 72.99 ± 6.00 years; 69.6% female) from the Minority Aging Research Study (MARS) who were without dementia at baseline and followed between 2 and 15 years (mean = 9 years). Participants completed a blood draw at baseline and annual cognitive evaluations. Serum was assayed for 9 peripheral inflammatory markers; 19 neuropsychological test scores were used to create indices of global cognition and five cognitive domains. Principal component analysis with varimax rotation characterized patterns of inflammation with factor loadings > 0.6 per component contributing to two composite scores representing acute/upstream and chronic/downstream inflammation. These composites were used as separate predictors in linear mixed regression models to determine associations with level and change in cognition adjusting for relevant covariates. Higher baseline upstream/acute inflammation associated with lower baseline semantic memory (p = .040) and perceptual speed (p = .046); it was not related to cognitive decline. By contrast, higher baseline downstream/chronic inflammation associated with faster declines in global cognition (p = .010), episodic (p = .027) and working memory (p = .006); it was not related to baseline cognition. For older Black adults, chronic, but not acute, inflammation may be a risk factor for changes in cognition.

Liver kinase B1 depletion from astrocytes worsens disease in a mouse model of multiple sclerosis.

Liver kinase B1 (LKB1) is a ubiquitously expressed kinase involved in the regulation of cell metabolism, growth, and inflammatory activation. We previously reported that a single nucleotide polymorphism in the gene encoding LKB1 is a risk factor for multiple sclerosis (MS). Since astrocyte activation and metabolic function have important roles in regulating neuroinflammation and neuropathology, we examined the serine/threonine kinase LKB1 in astrocytes in a chronic experimental autoimmune encephalomyelitis mouse model of MS. To reduce LKB1, a heterozygous astrocyte-selective conditional knockout (het-cKO) model was used. While disease incidence was similar, disease severity was worsened in het-cKO mice. RNAseq analysis identified Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways enriched in het-cKO mice relating to mitochondrial function, confirmed by alterations in mitochondrial complex proteins and reductions in mRNAs related to astrocyte metabolism. Enriched pathways included major histocompatibility class II genes, confirmed by increases in MHCII protein in spinal cord and cerebellum of het-cKO mice. We observed increased numbers of CD4+ Th17 cells and increased neuronal damage in spinal cords of het-cKO mice, associated with reduced expression of choline acetyltransferase, accumulation of immunoglobulin-γ, and reduced expression of factors involved in motor neuron survival. In vitro, LKB1-deficient astrocytes showed reduced metabolic function and increased inflammatory activation. These data suggest that metabolic dysfunction in astrocytes, in this case due to LKB1 deficiency, can exacerbate demyelinating disease by loss of metabolic support and increase in the inflammatory environment.

Adherence to Long-Term Follow-Up of Patients with Life-Threatening, Inhaled Synthetic Cannabinoids-Associated Coagulopathy in Chicago.

A large-scale outbreak of life-threatening, inhaled synthetic cannabinoids (Spice/K2)-associated coagulopathy with bleeding complications was recently reported in Illinois. The causative agents were brodifacoum, difenacoum, and bromadiolone, potent, long-acting, 4-hydroxycoumarin anticoagulant rodenticides (LAAR) that were mixed with Spice/K2 products procured and then inhaled by the victims. We report on 3 poisoned patients who reside in underserved, socioeconomically disadvantaged neighborhoods of Chicago that were admitted and treated successfully at two inner-city, tertiary care hospitals in Chicago. The patients were discharged from the hospitals on daily long-term high-dose oral vitamin K1 (VK1), provided free of charge. However, 2 patients were lost to follow-up prior to safe discontinuation of oral VK1 therapy. The third patient was treated and followed successfully for 7 months when VK1 was discontinued. We conclude that prolonged oral VK1 therapy and follow-up of acute, life-threatening LAAR poisoning are variable and present challenges to healthcare providers. Appropriate practice guidelines to improve patient access and adherence to daily high-dose oral VK1 therapy and follow-up should be developed and implemented.

Transcriptome analysis of alcohol-treated microglia reveals downregulation of beta amyloid phagocytosis.

BACKGROUND: Microglial activation contributes to the neuropathology associated with chronic alcohol exposure and withdrawal, including the expression of inflammatory and anti-inflammatory genes. In the current study, we examined the transcriptome of primary rat microglial cells following incubation with alcohol alone, or alcohol together with a robust inflammatory stimulus. METHODS: Primary microglia were prepared from mixed rat glial cultures. Cells were incubated with 75 mM ethanol alone or with proinflammatory cytokines ("TII": IL1ß, IFNγ, and TNFα). Isolated mRNA was used for RNAseq analysis and qPCR. Effects of alcohol on phagocytosis were determined by uptake of oligomeric amyloid beta. RESULTS: Alcohol induced nitrite production in control cells and increased nitrite production in cells co-treated with TII. RNAseq analysis of microglia exposed for 24 h to alcohol identified 312 differentially expressed mRNAs ("Alc-DEs"), with changes confirmed by qPCR analysis. Gene ontology analysis identified phagosome as one of the highest-ranking KEGG pathways including transcripts regulating phagocytosis. Alcohol also increased several complement-related mRNAs that have roles in phagocytosis, including C1qa, b, and c; C3; and C3aR1. RNAseq analysis identified over 3000 differentially expressed mRNAs in microglia following overnight incubation with TII; and comparison to the group of Alc-DEs revealed 87 mRNAs modulated by alcohol but not by TII, including C1qa, b, and c. Consistent with observed changes in phagocytosis-related mRNAs, the uptake of amyloid beta1-42, by primary microglia, was reduced by alcohol. CONCLUSIONS: Our results define alterations that occur to microglial gene expression following alcohol exposure and suggest that alcohol effects on phagocytosis could contribute to the development of Alzheimer's disease.

Analysis of lanthionine ketimine ethyl ester in mouse serum, whole blood and tissues using ultrahigh-pressure liquid chromatography/tandem mass spectrometry.

RATIONALE: Preclinical studies in the search for treatments for several neurodegenerative diseases have identified lanthionine ketimine (LK) and its monoethyl ester derivative (LKE) as potential candidates. An ultrahigh-pressure liquid chromatography/tandem mass spectrometry (UHPLC/MS/MS) assay was developed to evaluate bioavailability by measuring these compounds in mouse serum, whole blood and brain tissue. METHODS: Following administration of LKE to mice for 3 days in chow at 300 ppm, the animals were sacrificed, and LKE was extracted from serum, whole blood and brain tissues through protein precipitation using cold methanol. To enhance chromatographic separation and electrospray ionization, LK was methylated using diazomethane. Separations were carried out using C18 reversed-phase UHPLC, and quantitative measurements were obtained using on-line triple-quadruple mass spectrometry with positive ion electrospray ionization, collision-induced dissociation and selected reaction monitoring. Tolbutamide was used as internal standard. RESULTS: LKE showed good recovery ranging from 77-90% in serum and 82-88% in brain tissue. An eight-point standard curve ranging from 0.005 to 4.6 µM was linear (R2 0.998). The average LKE detected in mouse serum was 277.42 nM, while the concentration in whole blood was 38 nM. Neither LK nor LKE was detected in brain tissues. CONCLUSIONS: A rapid quantitative method to measure LKE in mouse serum, whole blood and brain tissues using UHPLC/MS/MS was developed and validated following FDA guidelines. This method is suitable for bioavailability and pharmacokinetic studies.

Membrane Cholesterol Modulates Superwarfarin Toxicity.

Superwarfarins are modified analogs of warfarin with additional lipophilic aromatic rings, up to 100-fold greater potency, and longer biological half-lives. We hypothesized that increased hydrophobicity allowed interactions with amphiphilic membranes and modulation of biological responses. We find that superwarfarins brodifacoum and difenacoum increase lactate production and cell death in neuroblastoma cells. In contrast, neither causes changes in glioma cells that have higher cholesterol content. After choleterol depletion, lactate production was increased and cell viability was reduced. Drug-membrane interactions were examined by surface X-ray scattering using Langmuir monolayers of dipalmitoylphosphatidylcholine and/or cholesterol. Specular X-ray reflectivity data revealed that superwarfarins, but not warfarin, intercalate between dipalmitoylphosphatidylcholine molecules, whereas grazing incidence X-ray diffraction demonstrated changes in lateral crystalline order of the film. Neither agent showed significant interactions with monolayers containing >20% cholesterol. These findings demonstrate an affinity of superwarfarins to biomembranes and suggest that cellular responses to these agents are regulated by cholesterol content.

Causes, consequences, and cures for neuroinflammation mediated via the locus coeruleus: noradrenergic signaling system.

Aside from its roles in as a classical neurotransmitter involved in regulation of behavior, noradrenaline (NA) has other functions in the CNS. This includes restricting the development of neuroinflammatory activation, providing neurotrophic support to neurons, and providing neuroprotection against oxidative stress. In recent years, it has become evident that disruption of physiological NA levels or signaling is a contributing factor to a variety of neurological diseases and conditions including Alzheimer's disease (AD) and Multiple Sclerosis. The basis for dysregulation in these diseases is, in many cases, due to damage occurring to noradrenergic neurons present in the locus coeruleus (LC), the major source of NA in the CNS. LC damage is present in AD, multiple sclerosis, and a large number of other diseases and conditions. Studies using animal models have shown that experimentally induced lesion of LC neurons exacerbates neuropathology while treatments to compensate for NA depletion, or to reduce LC neuronal damage, provide benefit. In this review, we will summarize the anti-inflammatory and neuroprotective actions of NA, summarize examples of how LC damage worsens disease, and discuss several approaches taken to treat or prevent reductions in NA levels and LC neuronal damage. Further understanding of these events will be of value for the development of treatments for AD, multiple sclerosis, and other diseases and conditions having a neuroinflammatory component. The classical neurotransmitter noradrenaline (NA) has critical roles in modulating behaviors including those involved in sleep, anxiety, and depression. However, NA can also elicit anti-inflammatory responses in glial cells, can increase neuronal viability by inducing neurotrophic factor expression, and can reduce neuronal damage due to oxidative stress by scavenging free radicals. NA is primarily produced by tyrosine hydroxylase (TH) expressing neurons in the locus coeruleus (LC), a relatively small brainstem nucleus near the IVth ventricle which sends projections throughout the brain and spinal cord. It has been known for close to 50 years that LC neurons are lost during normal aging, and that loss is exacerbated in neurological diseases including Parkinson's disease and Alzheimer's disease. LC neuronal damage and glial activation has now been documented in a variety of other neurological conditions and diseases, however, the causes of LC damage and cell loss remain largely unknown. A number of approaches have been developed to address the loss of NA and increased inflammation associated with LC damage, and several methods are being explored to directly minimize the extent of LC neuronal cell loss or function. In this review, we will summarize some of the consequences of LC loss, consider several factors that likely contribute to that loss, and discuss various ways that have been used to increase NA or to reduce LC damage. This article is part of the 60th Anniversary special issue.

Glial cell biology in the Great Lakes region.

We report on the tenth bi-annual Great Lakes Glial meeting, held in Traverse City, Michigan, USA, September 27-29 2015. The GLG meeting is a small conference that focuses on current research in glial cell biology. The array of functions that glial cells (astrocytes, microglia, oligodendrocytes, Schwann cells) play in health and disease is constantly increasing. Despite this diversity, GLG meetings bring together scientists with common interests, leading to a better understanding of these cells. This year's meeting included two keynote speakers who presented talks on the regulation of CNS myelination and the consequences of stress on Schwann cell biology. Twenty-two other talks were presented along with two poster sessions. Sessions covered recent findings in the areas of microglial and astrocyte activation; age-dependent changes to glial cells, Schwann cell development and pathology, and the role of stem cells in glioma and neural regeneration.

Sulfatides in extracellular vesicles isolated from plasma of multiple sclerosis patients.

Extracellular vesicles (EVs) are membrane nanovesicles of diverse sizes secreted by different cell types and are involved in intercellular communication. EVs shuttle proteins, nucleic acids, and lipids that reflect their cellular origin and could mediate their biological function in recipient cells. EVs circulate in biological fluids and are considered as potential biomarkers that could be used to analyze and characterize disease development, course and response to treatment. EVs exhibit specific distribution of glycolipids and membrane organization, but little is known about the biological significance of this distribution or how it could contribute to pathological conditions such as multiple sclerosis (MS). We provide the first description of sulfatide composition in plasma-derived EVs by ultra-high-performance liquid chromatography tandem mass spectrometry. We found that EVs of different sizes showed C16:0 sulfatide but no detectable levels of C18:0, C24:0, or C24:1 sulfatide species. Small EVs isolated at 100,000 × g-enriched in exosomes-from plasma of patients with MS showed a significant increase of C16:0 sulfatide compared with healthy controls. Nanoparticle tracking analysis showed that the particle size distribution in MS plasma was significantly different compared with healthy controls. Characterization of small EVs isolated from MS plasma showed similar protein content and similar levels of exosomal markers (Alix, Rab-5B) and vesicular marker MHC class I (major histocompatibility complex class I) compared with healthy controls. Our findings indicate that C16:0 sulfatide associated with small EVs is a candidate biomarker for MS that could potentially reflect pathological changes associated with this disease and/or the effects of its treatment. © 2016 Wiley Periodicals, Inc.

Lanthionine ketimine ester provides benefit in a mouse model of multiple sclerosis.

Lanthionine ketimine (LK) is a natural sulfur amino acid metabolite which binds to collapsin response mediator protein-2 (CRMP2), an abundant brain protein that interacts with multiple partners to regulate microtubule dynamics, neurite growth and retraction, axonal transport, and neurotransmitter release. LK ethyl-ester (LKE) is a cell-permeable synthetic derivative that promotes neurogenesis, suppresses nitric oxide production from microglia, and reduces neurotoxicity of microglia-conditioned medium. These properties led us to test the effects of LKE in experimental autoimmune encephalomyelitis (EAE), a commonly used mouse model of multiple sclerosis. Female C57Bl/6 mice were immunized with myelin oligodendrocyte glycoprotein peptide 35-55 to develop a chronic disease. LKE was provided in the chow at 100 ppm, ad libitum beginning when the mice reached moderate clinical signs. Over the following 4 weeks the LKE-treated mice showed a significant reduction in clinical signs compared to vehicle-treated mice. LKE dose dependently reduced IFNγ production from splenic T cells, but had no effect on IL-17 production suggesting protective effects were mediated within the CNS. Electron microscopy revealed that, compared to sham mice, EAE mice had significant neurodegeneration in both the optic nerve and spinal cord, which was reduced in the LKE-treated mice. In contrast only minimal disruption of myelin was observed at this time point. In the optic nerve, measurements of axon caliber and myelin thickness showed little changes between sham and EAE mice, however, treatment with LKE increased the percentage of axons with thicker myelin and with larger axon calibers. In the spinal cord, only smaller effects of LKE on myelin thickness were observed. The effects of LKE were associated with a reduced relative level of phosphorylated CRMP2 to CRMP2. Together, these results demonstrate that LKE reduces neurodegeneration in a chronic EAE model of MS, which could have translation potential for treatment of progressive forms of MS.

Brodifacoum induces early hemoglobinuria and late hematuria in rats: novel rapid biomarkers of poisoning.

INTRODUCTION: Brodifacoum (BDF) is a superwarfarin that is used primarily as a rodenticide. There have been increasing numbers of reports of human cases of accidental or intentional BDF ingestion with high mortality rate. Its broad availability and high lethality suggest that BDF should be considered a potential chemical threat. Currently, there is no biomarker for early detection of BDF ingestion in humans; patients typically present with severe coagulopathy. Since we demonstrated earlier that warfarin can induce acute kidney injury with hematuria, we tested whether BDF would also lead to change in urinary biomarkers. MATERIAL AND METHODS: BDF was administered to Sprague Dawley rats via oral gavage. N-acetylcysteine (NAC) was given per os in drinking water 24 h prior to BDF. Urinalysis was performed at different times after BDF administration. Anticoagulation and serum creatinine levels were analyzed in the blood. RESULTS: We observed that within a few hours the animals developed BDF-dose-dependent transient hemoglobinuria, which ceased within 24 h. This was accompanied by a transient decrease in hematocrit, gross hemolysis and an increase in free hemoglobin in the serum. At later times, animals developed true hematuria with red blood cells in the urine, which was associated with BDF anticoagulation. NAC prevented early hemoglobinuria, but not late hematuria associated with BDF. CONCLUSIONS: We propose that transient early hemoglobinuria (associated with oxidative stress) with consecutive late hematuria (associated with anticoagulation) are novel biomarkers of BDF poisoning, and they can be used in clinical setting or in mass casualty with BDF to identify poisoned patients.

Effects of peptide fraction and counter ion on the development of clinical signs in experimental autoimmune encephalomyelitis.

The most commonly used immunogen to induce experimental autoimmune encephalomyelitis is MOG35-55 , a 21-residue peptide derived from myelin oligodendrocyte glycoprotein (MOG). In most studies, mice exhibit a chronic disease; however, in some studies mice show a transient disease. One variable that is not often controlled for is the peptide fraction of the purified MOG material, which can vary from less than 50% to over 90%, with the remainder of mass primarily comprised of the counter ion used for peptide purification. We compared the development of clinical signs in female C57Bl6 mice immunized with two commercially available MOG35-55 peptides of similar purity but different peptide fraction (MOG-A being 45%; MOG-B being 72%). A single immunization with MOG-A induced a chronic disease course with some recovery at later stages, whereas immunization with MOG-B induced a similar course of disease but with significantly lower average clinical scores despite a higher peptide content. The addition of a booster immunization significantly increased clinical severity with both preparations, and significantly reduced the average day of onset using MOG-A. To determine if the counter ion could influence disease, we compared MOG-B-containing trifluoroacetate with MOG-B-containing acetate. Although disease incidence and severity were similar, the average day of disease onset occurred approximately 5 days earlier with the use of MOG-B-containing trifluoroacetate. These results demonstrate that differences in peptide fraction influence the course of encephalomyelitis disease, which may be due in part to the levels of counter ions present in the purified material. These findings underscore the fact that a knowledge of peptide fraction is as critical as knowledge of peptide purity when using peptides from different sources.

Intraosseous lipid emulsion: an effective alternative to IV delivery in emergency situations.

OBJECTIVE: To determine whether intraosseous infusion of a lipid emulsion reverses cardiac pharmacotoxicity in anaesthetized rats. DESIGN: Prospective, randomized animal study. SETTING: Academic research laboratory. SUBJECTS: Adult, male Sprague-Dawley rats. INTERVENTIONS: We assigned 25 male Sprague-Dawley rats into four groups: intraosseous lipid emulsion, intraosseous saline, IV lipid emulsion, and sham/null. Rats were anesthetized with 1.5% isoflurane and 95% oxygen. The left internal carotid artery and both internal jugular veins were cannulated and a flow probe was placed on the right carotid artery. Subsequently, in animals assigned to the intraosseous groups, the greater trochanter of the left proximal femur was exposed and the intraosseous space was cannulated. After surgical recovery, bupivacaine (10 mg/kg) was injected IV over 20 seconds followed 10 seconds later by treatment with one of the following: intraosseous lipid-emulsion (10 mL/kg over 180 s), intraosseous saline (10 mL/kg over 180 s), IV lipid-emulsion (10 mL/kg over 90 s), or no treatment (sham/null). MEASUREMENTS AND MAIN RESULTS: Electrocardiogram, aortic blood pressure, and carotid blood flow were recorded continuously. Rats treated with intraosseous lipid emulsion experienced a significantly faster recovery of hemodynamic variables (return of 50% flow; median [CI]: 160 s [105-263 s]) than did rats treated with saline (471 s [283-611 s]; p < 0.05) or animals with no treatment (415 s [340-539 s], p < 0.05), but at a similar rate to animals treated with IV lipid emulsion (176 s [152-217 s], p = not significant). All groups experienced persistent negative chronotropic effects. A compensatory increase in systemic arterial pressure was observed in rats treated with lipid emulsion. CONCLUSION: These proof-of-principle data indicate that intraosseous infusion of lipid emulsion rapidly reverses bupivacaine-induced cardiac toxicity in rats. Further studies are warranted to optimize this novel route of lipid emulsion injection in emergency situations when intravascular access is not secured.

Noradrenergic regulation of glial activation: molecular mechanisms and therapeutic implications.

It has been known for many years that the endogenous neurotransmitter noradrenaline (NA) exerts anti-inflammatory and neuroprotective effects both in vitro and in vivo. In many cases the site of action of NA are beta-adrenergic receptors (ßARs), causing an increase in intracellular levels of cAMP which initiates a broad cascade of events including suppression of inflammatory transcription factor activities, alterations in nuclear localization of proteins, and induction of patterns of gene expression mediated through activity of the CREB transcription factor. These changes lead not only to reduced inflammatory events, but also contribute to neuroprotective actions of NA by increasing expression of neurotrophic substances including BDNF, GDNF, and NGF. These properties have prompted studies to determine if treatments with drugs to raise CNS NA levels could provide benefit in various neurological conditions and diseases having an inflammatory component. Moreover, increasing evidence shows that disruptions in endogenous NA levels occurs in several diseases and conditions including Alzheimer's disease (AD), Parkinson's disease (PD), Down's syndrome, posttraumatic stress disorder (PTSD), and multiple sclerosis (MS), suggesting that damage to NA producing neurons is a common factor that contributes to the initiation or progression of neuropathology. Methods to increase NA levels, or to reduce damage to noradrenergic neurons, therefore represent potential preventative as well as therapeutic approaches to disease.

Validation of tag SNPs for multiple sclerosis HLA risk alleles across the 1000 genomes panel.

Currently, the genetic variants strongly associated with risk for Multiple Sclerosis (MS) are located in the Major Histocompatibility Complex. This includes DRB1*15:01 and DRB1*15:03 alleles at the HLA-DRB1 locus, the latter restricted to African populations; the DQB1*06:02 allele at the HLA-DQB1 locus which is in high linkage disequilibrium (LD) with DRB1*15:01; and protective allele A*02:01 at the HLA-A locus. HLA allele identification is facilitated by co-inherited ('tag') single nucleotide polymorphisms (SNPs); however, SNP validation is not typically done outside of the discovery population. We examined 19 SNPs reported to be in high LD with these alleles in 2,502 healthy subjects included in the 1000 Genomes panel having typed HLA data. Examination of 3 indices (LD R2 values, sensitivity and specificity, minor allele frequency) revealed few SNPs with high tagging performance. All SNPs examined that tag DRB1*15:01 were in perfect LD in the British population; three showed high tagging performance in 4 of the 5 European, and 2 of the 4 American populations. For DQB1*06:02, with no previously validated tag SNPs, we show that rs3135388 has high tagging performance in one South Asian, one American, and one European population. We identify for the first time that rs2844821 has high tagging performance for A*02:01 in 5 of 7 African populations including African Americans, and 4 of the 5 European populations. These results provide a basis for selecting SNPs with high tagging performance to assess HLA alleles across diverse populations, for MS risk as well as for other diseases and conditions.

Short-term treatment with cholestyramine increases long-acting anticoagulant rodenticide clearance from rabbits without affecting plasma vitamin K1 levels or blood coagulation.

Administration of high-dose vitamin K1 (VK1) overcomes coagulopathy and bleeding elicited by acute poisoning with long-acting anticoagulant rodenticides (LAARs). However, long-term (months) treatment is required due to long LAAR biological half-lives that may lead to poor compliance and recurrent coagulopathy. The half-lives of LAARs are extended by slow metabolism, and similar to warfarin, are thought to undergo enterohepatic recirculation. We now show that treatment with the bile acid sequestrant cholestyramine (CSA) administered concomitantly with VK1 decreases plasma LAAR levels and increases LAAR fecal excretion. Daily CSA treatment for 14 days did not reduce plasma VK1 levels, or increase prothrombin time. Collectively, these data show that CSA accelerates LAAR clearance from rabbits without adverse effects on VK1 anticoagulation, and could provide an additional therapeutic option for treatment of LAAR poisoning.

Investigating the metabolite signature of an altered oral microbiota as a discriminant factor for multiple sclerosis: a pilot study.

In multiple sclerosis (MS), alterations of the gut microbiota lead to inflammation. However, the role of other microbiomes in the body in MS has not been fully elucidated. In a pilot case-controlled study, we carried out simultaneous characterization of faecal and oral microbiota and conducted an in-depth analysis of bacterial alterations associated with MS. Using 16S rRNA sequencing and metabolic inference tools, we compared the oral/faecal microbiota and bacterial metabolism pathways in French MS patients (n = 14) and healthy volunteers (HV, n = 21). A classification model based on metabolite flux balance was established and validated in an independent German cohort (MS n = 12, HV n = 38). Our analysis revealed decreases in diversity indices and oral/faecal compartmentalization, the depletion of commensal bacteria (Aggregatibacter and Streptococcus in saliva and Coprobacter and Roseburia in faeces) and enrichment of inflammation-associated bacteria in MS patients (Leptotrichia and Fusobacterium in saliva and Enterobacteriaceae and Actinomyces in faeces). Several microbial pathways were also altered (the polyamine pathway and remodelling of bacterial surface antigens and energetic metabolism) while flux balance analysis revealed associated alterations in metabolite production in MS (nitrogen and nucleoside). Based on this analysis, we identified a specific oral metabolite signature in MS patients, that could discriminate MS patients from HV and rheumatoid arthritis patients. This signature allowed us to create and validate a discrimination model on an independent cohort, which reached a specificity of 92%. Overall, the oral and faecal microbiomes were altered in MS patients. This pilot study highlights the need to study the oral microbiota and oral health implications in patients with autoimmune diseases on a larger scale and suggests that knowledge of the salivary microbiome could help guide the identification of new pathogenic mechanisms associated with the microbiota in MS patients.

mTOR kinase, a key player in the regulation of glial functions: relevance for the therapy of multiple sclerosis.

The mammalian target of rapamycin (mTOR) is a serine/threonine protein kinase with a central role in the regulation of cell growth and proliferation, and several intracellular processes, such as mRNA transcription and translation, autophagy and cytoskeletal organization. The relevance of this pathway in the regulation of the immune system is well characterized. mTOR is essential for the proper activation and proliferation of effector T cells, restricts the development of regulatory T cells, and downregulates innate immune responses. Recently, a direct role of mTOR in the modulation of glial functions has also been recognized. Data from our group and others support the notion that mTOR is involved in microglial proinflammatory activation. The kinase regulates several intracellular processes in astrocytes, among which the rate of mRNA degradation of the inducible form of NO synthase. Therefore, the inhibition of mTOR kinase activity in glial cells results in anti-inflammatory actions, suggesting possible beneficial effects of mTOR inhibitors (like rapamycin) in the treatment of inflammatory-based pathologies of the central nervous system. In contrast, mTOR plays an important role in the regulation of oligodendrocyte development and myelination process as well as several neuronal functions, which may limit this therapeutic approach. Nevertheless, as reviewed here, there is robust evidence that rapamycin ameliorates the clinical course of both the relapsing-remitting and the chronic experimental autoimmune encephalomyelitis (EAE), and significantly reduces the hyperalgesia observed before clinical development of EAE. These findings may have important clinical implications for the therapy of multiple sclerosis.

Astrocyte lipocalin-2 modestly effects disease severity in a mouse model of multiple sclerosis while reducing mature oligodendrocyte protein and mRNA expression.

Roles for lipocalin-2 (LCN2, also referred to as neutrophil gelatinase associated lipocalin, NGAL) in the progression of disease in multiple sclerosis and its animal models have been reported; however, the importance of astrocyte-derived LCN2, a major source of LCN2, have not been defined. We found that clinical scores in experimental autoimmune encephalomyelitis (EAE) were modestly delayed in mice with conditional knockout of LCN2 from astrocytes, associated with a small decrease in astrocyte GFAP expression. Immunostaining and qPCR of spinal cord samples showed decreased oligodendrocyte proteolipid protein and transcription factor Olig2 expression, but no changes in PDGFRα expression. These results suggest astrocyte LCN2 contributes to early events in EAE and reduces damage to mature oligodendrocytes at later times.

Genetic deletion of c-Jun amino-terminal kinase 3 (JNK3) modestly increases disease severity in a mouse model of multiple sclerosis.

The c-Jun amino terminal kinases (JNKs) regulate transcription, and studies suggest they contribute to neuropathology in the EAE model of MS. To examine the role of the JNK3 isoform, we compared EAE in JNK3 null mice to wild type (WT) littermates. Although disease severity was similar in female mice, in male JNK3 null mice the day of onset and time to reach 100% incidence occurred sooner, and disease severity was increased. While glial activation in spinal cord was similar, white matter lesions were increased in JNK3 null mice. These results suggest JNK3 normally limits EAE disease in a sex-dependent manner.