Ceruloplasmin-deficient mice show changes in PTM profiles of proteins involved in messenger RNA processing and neuronal projections and synaptic processes.

Ceruloplasmin (Cp) is a multicopper oxidase with ferroxidase properties being of importance to the mobilisation and export of iron from cells and its ability to bind copper. In ageing humans, Cp deficiency is known to result in aceruloplasminemia, which among other is characterised by neurological symptoms. To obtain novel information about the functions of Cp in the central nervous system (CNS) we compared the brain proteome in forebrains from asymptomatic 4-6-month-old Cp-deficient (B6N(Cg)-Cptm1b(KOMP)Wtsi /J) and wild-type mice. Of more than 5600 quantified proteins, 23 proteins, were regulated, whereas more than 1200 proteins had regulated post-translational modifications (PTMs). The genes of the regulated proteins, glycoproteins and phosphoproteins appeared mostly to be located to neurons and oligodendrocyte precursor cells. Cp deficiency especially affected the function of proteins involved in the extension of neuronal projections, synaptic signalling and cellular mRNA processing and affected the expression of proteins involved in neurodegenerative disease and diabetes. Iron concentration and transferrin saturation were reduced in the blood of even younger, 3- to 5-month-old, Cp-deficient mice. Iron act as cofactor in many enzymatic processes and reactions. Changes in iron availability and oxidation as consequence of Cp deficiency could therefore affect the synthesis of proteins and lipids. This proteomic characterisation is to our knowledge the first to document the changes taking place in the CNS-proteome and its phosphorylation and glycosylation state in Cp-deficient mice.

Migraine with aura and risk of silent brain infarcts and white matter hyperintensities: an MRI study.

A small number of population-based studies reported an association between migraine with aura and risk of silent brain infarcts and white matter hyperintensities in females. We investigated these relations in a population-based sample of female twins. We contacted female twins ages 30-60 years identified through the population-based Danish Twin Registry. Based on questionnaire responses, twins were invited to participate in a telephone-based interview conducted by physicians. Headache diagnoses were established according to the International Headache Society criteria. Cases with migraine with aura, their co-twins, and unrelated migraine-free twins (controls) were invited to a brain magnetic resonance imaging scan performed at a single centre. Brain scans were assessed for the presence of infarcts, and white matter hyperintensities (visual rating scales and volumetric analyses) blinded to headache diagnoses. Comparisons were based on 172 cases, 34 co-twins, and 139 control subjects. Compared with control subjects, cases did not differ with regard to frequency of silent brain infarcts (four cases versus one control), periventricular white matter hyperintensity scores [adjusted mean difference (95% confidence interval): -0.1 (-0.5 to 0.2)] or deep white matter hyperintensity scores [adjusted mean difference (95% confidence interval): 0.1 (-0.8 to 1.1)] assessed by Scheltens' scale. Cases had a slightly higher total white matter hyperintensity volume compared with controls [adjusted mean difference (95% confidence interval): 0.17 (-0.08 to 0.41) cm(3)] and a similar difference was present in analyses restricted to twin pairs discordant for migraine with aura [adjusted mean difference 0.21 (-0.20 to 0.63)], but these differences did not reach statistical significance. We found no evidence of an association between silent brain infarcts, white matter hyperintensities, and migraine with aura.

A Urinary Metabolic Signature for Multiple Sclerosis and Neuromyelitis Optica.

Urine is a metabolite-rich biofluid that reflects the body's effort to maintain chemical and osmotic homeostasis. Clinical diagnosis routinely relies on urine samples because the collection process is easy and noninvasive. Despite these advantages, urine is an under-investigated source of biomarkers for multiple sclerosis (MS). Nuclear magnetic resonance spectroscopy (NMR) has become a common approach for analyzing urinary metabolites for disease diagnosis and biomarker discovery. For illustration of the potential of urinary metabolites for diagnosing and treating MS patients, and for differentiating between MS and other illnesses, 38 urine samples were collected from healthy controls, MS patients, and neuromyelitis optica-spectrum disorder (NMO-SD) patients and analyzed with NMR, multivariate statistics, one-way ANOVA, and univariate statistics. Urine from MS patients exhibited a statistically distinct metabolic signature from healthy and NMO-SD controls. A total of 27 metabolites were differentially altered in the urine from MS and NMO-SD patients and were associated with synthesis and degradation of ketone bodies, amino acids, propionate and pyruvate metabolism, tricarboxylic acid cycle, and glycolysis. Metabolites altered in urine from MS patients were shown to be related to known pathogenic processes relevant to MS, including alterations in energy and fatty acid metabolism, mitochondrial activity, and the gut microbiota.

Myelin-specific T cells induce interleukin-1beta expression in lesion-reactive microglial-like cells in zones of axonal degeneration.

Infiltration of myelin-specific T cells into the central nervous system induces the expression of proinflammatory cytokines in patients with multiple sclerosis (MS). We have previously shown that myelin-specific T cells are recruited into zones of axonal degeneration, where they stimulate lesion-reactive microglia. To gain mechanistic insight, we used RNA microarray analysis to compare the transcript profile in hippocampi from perforant pathway axonal-lesioned mice with and without adoptively transferred myelin-specific T cells 2 days postlesion, when microglia are clearly lesion reactive. Pathway analysis revealed that, among the 1,447 differently expressed transcripts, the interleukin (IL)-1 pathway including all IL-1 receptor ligands was upregulated in the presence of myelin-specific T cells. Quantitative polymerase chain reaction showed increased mRNA levels of IL-1ß, IL-1α, and IL-1 receptor antagonist in the T-cell-infiltrated hippocampi from axonal-lesioned mice. In situ hybridization and immunohistochemistry showed a T-cell-enhanced lesion-specific expression of IL-1ß mRNA and protein, respectively, and induction of the apoptosis-associated speck-like protein, ASC, in CD11b(+) cells. Double in situ hybridization showed colocalization of IL-1ß mRNA in a subset of CD11b mRNA(+) cells, of which many were part of cellular doublets or clusters, characteristic of proliferating, lesion-reactive microglia. Double-immunofluorescence showed a T-cell-enhanced colocalization of IL-1ß to CD11b(+) cells, including lesion-reactive CD11b(+) ramified microglia. These results suggest that myelin-specific T cells stimulate lesion-reactive microglial-like cells to produce IL-1ß. These findings are relevant to understand the consequences of T-cell infiltration in white and gray matter lesions in patients with MS.

Hyperammonaemic Encephalopathy Caused by Adult-Onset Ornithine Transcarbamylase Deficiency.

Hyperammonaemic encephalopathy in adults is a rare condition in the absence of liver disease and is associated with a high mortality and risk of permanent neurological deficits. Seldomly, the condition is caused by an inborn error of metabolism in the urea cycle, triggered by an exogenic factor such as gastrointestinal haemorrhage, gastric bypass surgery, starvation, seizures, vigorous exercise, burn injuries, or drugs hampering the elimination of ammonia. Here, we present a fatal case of an unrecognized genetic ornithine transcarbamylase deficiency (OTCD) presenting with a subacute progressive encephalopathy. We review the current literature and discuss the differential diagnosis and treatment options. As swift diagnosis and initiation of treatment is vital, awareness of hyperammonaemic encephalopathy and its possible causes can help improve the prognosis of this condition.

Inflammatory profiles in plasma and cerebrospinal fluid of patients with neurosarcoidosis.

METHODS: Cerebrospinal fluid (CSF) and plasma levels of 38 biomarkers from 20 neurosarcoidosis (NS) patients were compared to healthy controls (HC). RESULTS: In CSF, 25 biomarkers were significantly elevated compared to HC: IFNγ, TNFα, TNFß, IL-2, IL-6, IL-10, IL-12B, IL-15, IL-16, CCL2, CCL3, CCL4, CCL11, CCL13, CCL17, CCL22, CCL26, CXCL8, CXCL10, TNFR2, VEGF-A, PIGF, SAA, VCAM1, and ICAM1. In plasma, 12 biomarkers were significantly elevated compared to HC: IFNγ, TNFα, CCL2, CCL3, CCL4, CCL17, CXCL10, VEGFR1, PIGF, SAA, VCAM1, and ICAM1. CONCLUSION: NS patients have profoundly elevated cytokines, chemokines, vascular angiogenesis, and vascular injury biomarkers in CSF and plasma.

A prospective, one-year follow-up study of patients newly diagnosed with neurosarcoidosis.

METHODS: Twenty patients with newly diagnosed neurosarcoidosis were examined for multiple outcomes in an observational cohort study with 12-month follow-up. RESULTS: The patients' contrast-enhancing lesions on MRI scans reduced during treatment (p < 0.0001). The mean modified Rankin Score improved from 3.0 to 1.8 (p < 0.0001), and 75% of patients experienced clinically important improvement. Patients improved on the Symbol Digit Modalities Test (p < 0.0001) and on SF-36 Physical (p = 0.003) and Mental Component Summary scores (p = 0.03). Proportions of patients with substantial fatigue (75%) and high depression score (35%) were unchanged. CONCLUSIONS: 12-month immunosuppression improved several outcomes, and 75% of patients experienced clinically important improvement.

Evaluation of functional outcome measures after fampridine treatment in patients with multiple sclerosis - An interventional follow-up study.

OBJECTIVE: The purpose of this interventional study on participants with multiple sclerosis (MS) with walking disability was to evaluate changes in functional hand and walking measurements after fampridine treatment, after stratifying by the Expanded Disability Status Scale (EDSS). We furthermore wanted to investigate different functional measurements to evaluate their ability to detect responders to fampridine with a clinically relevant improvement. METHODS: Patients were recruited from the MS Clinic at Odense University Hospital and were classified into two disability groups based on their EDSS score (moderate EDSS (EDSSMod) 4.5-5.5 [n = 19] and severe EDSS (EDSSSev) 6.0-7.0 [n = 14]). At baseline (visit 1) they completed the Timed 25-Foot Walk (T25FW), 2-Minute Walk Test (2MWT), Nine Hold Peg Test (9HPT), 12-item Multiple Sclerosis Walking Scale (MSWS-12), and the Six Spot Step Test (SSST). Participants were given 10 mg twice daily fampridine for 14 days before retested (visit 2). For each measurement, cut-off values were used to define responders with a clinically relevant improvement to treatment. The measurements were evaluated separately and in combination. RESULTS: Of the 33 participants, 25 (75.8%) were identified as having a clinically relevant improvement (CRI). For all patients combined (EDSSAll), all five measurements showed significant functional improvement after treatment. For the individual measurements, the highest participant response rates after 14 days of fampridine treatment were seen on the MSWS-12 (57.6%) and 2MWT (42.4%). The 2MWT also showed the largest performance improvement (18.5%) from visit 1 to visit 2. For patients with severe disability (EDSSSev), no significant improvement was seen after fampridine treatment on the T25FW, and most of the responders to T25FW had moderate disability (EDSSMod, 71.5%). Conversely for the SSST, most responders were EDSSSev (83.3%). No participants had a clinically relevant improvement on the 9HPT. The combination of T25FW, SSST, and MSWS-12 was less sensitive in distinguishing responders from non-responders, whereas the combination of 2MWT and MSWS-12 identified the same responders and could better distinguish fampridine responders from non-responders. CONCLUSION: EDSS level did not influence the effect of fampridine treatment on functional hand and walking measures and the responsiveness of the measurements differed only a little between moderate and severe EDSS levels. The combination of self-reported walking capacity (MSWS-12) and walking endurance (2MWT) was better than T25FW, SSST, and MSWS-12 at detecting clinically meaningful improvement after fampridine treatment, which could prove useful in the clinical monitoring of walking disabilities in MS during fampridine treatment.

The Role of Non-Selective TNF Inhibitors in Demyelinating Events.

The use of non-selective tumor necrosis factor (TNF) inhibitors is well known in the treatment of inflammatory diseases such as rheumatoid arthritis, Crohn's disease, and psoriasis. Its use in neurological disorders is limited however, due to rare adverse events of demyelination, even in patients without preceding demyelinating disease. We review here the molecular and cellular aspects of this neuroinflammatory process in light of a case of severe monophasic demyelination caused by treatment with infliximab. Focusing on the role of TNF, we review the links between CNS inflammation, demyelination, and neurodegenerative changes leading to permanent neurological deficits in a young woman, and we discuss the growing evidence for selective soluble TNF inhibitors as a new treatment approach in inflammatory and neurological diseases.

Leukocyte TNFR1 and TNFR2 Expression Contributes to the Peripheral Immune Response in Cases with Ischemic Stroke.

Tumor necrosis factor receptor 1 and 2 (TNFR1 and TNFR2) have been found in brain parenchyma of stroke patients, and plasma levels are increased in the acute phase of stroke. We evaluated associations between TNFR1 and TNFR2 plasma levels and stroke severity, infarct size, and functional outcome. Furthermore, we examined cellular expression of TNFR1 and TNFR2 on leukocyte subpopulations to explore the origin of the increased receptor levels. Blood samples were taken from 33 acute ischemic stroke patients and 10 healthy controls. TNFR1 and TNFR2 plasma concentrations were measured and correlated against the Scandinavian Stroke Scale at admission, infarct volume, and the modified Rankin Scale score three months after stroke onset. Classical, intermediate, and non-classical monocytes as well as neutrophils were purified, and cellular expression of TNFR1 and TNFR2 was examined using flow cytometry. TNFR1 and TNFR2 plasma levels were both increased after ischemic stroke, but we found no correlation with patient outcome measurements. Compared to healthy controls, ischemic stroke patients had decreased non-classical monocyte and neutrophil populations expressing TNFR1 and increased neutrophils expressing TNFR2, and decreased non-classical populations co-expressing both TNFR1 and TNFR2. This study supports the hypothesis of an acute immunological response orchestrated by the peripheral immune system following an ischemic stroke. However, the origin of the increased TNFR1 and TNFR2 plasma levels could not be clearly linked to peripheral monocytes or neutrophils. Future studies are needed and will help clarify the potential role as treatment target.

Elevated Neurofilament Light Chain in Cerebrospinal Fluid and Plasma Reflect Inflammatory MRI Activity in Neurosarcoidosis.

BACKGROUND: Damage to axonal cells releases neurofilament light chain (NFL) into the cerebrospinal fluid and plasma. The objective of this study was to investigate NFL as a potential biomarker of disease activity in neurosarcoidosis. MRIs were graded according to enhancing lesions at different central nervous system (CNS) sites. RESULTS: In cerebrospinal fluid, levels of NFL were higher in neurosarcoidosis patients (n = 20) median 2304 pg/mL (interquartile range (IQR) 630-19,612) compared to 426 pg/mL (IQR 261-571) in extra-neurologic sarcoidosis patients (n = 20) and 336 pg/mL (IQR 194-402) in healthy controls (n = 11) (p = 0.0002). In plasma, levels of NFL were higher in neurosarcoidosis patients median 28.2 pg/mL (IQR 11.5-49.3) compared to 6.2 pg/mL (IQR 4.3-8.2) in extra-neurologic sarcoidosis patients and 7.1 pg/mL (IQR 6.2-9.0) in healthy controls (p = 0.0001). Levels in both cerebrospinal fluid and plasma were higher in neurosarcoidosis patients with moderate/severe enhancement than patients with mild enhancement on MRI (p = 0.009 and p = 0.005, respectively). To distinguish neurosarcoidosis patients from extra-neurologic patients and healthy controls, a cut-off level of 630 pg/mL in cerebrospinal fluid had 94% specificity and 79% sensitivity, while a cut-off level of 11.4 pg/mL in plasma had 97% specificity and 75% sensitivity. CONCLUSIONS: NFL levels in cerebrospinal fluid and plasma are significantly higher in neurosarcoidosis patients compared to extra-neurologic patients and healthy controls, and the levels correlate to the extent of inflammation on MRI.

Autoantibodies Against the Complement Regulator Factor H in the Serum of Patients With Neuromyelitis Optica Spectrum Disorder.

Neuromyelitis optica spectrum disorder (NMOSD) is an autoimmune inflammatory disease of the central nervous system (CNS), characterized by pathogenic, complement-activating autoantibodies against the main water channel in the CNS, aquaporin 4 (AQP4). NMOSD is frequently associated with additional autoantibodies and antibody-mediated diseases. Because the alternative pathway amplifies complement activation, our aim was to evaluate the presence of autoantibodies against the alternative pathway C3 convertase, its components C3b and factor B, and the complement regulator factor H (FH) in NMOSD. Four out of 45 AQP4-seropositive NMOSD patients (~9%) had FH autoantibodies in serum and none had antibodies to C3b, factor B and C3bBb. The FH autoantibody titers were low in three and high in one of the patients, and the avidity indexes were low. FH-IgG complexes were detected in the purified IgG fractions by Western blot. The autoantibodies bound to FH domains 19-20, and also recognized the homologous FH-related protein 1 (FHR-1), similar to FH autoantibodies associated with atypical hemolytic uremic syndrome (aHUS). However, in contrast to the majority of autoantibody-positive aHUS patients, these four NMOSD patients did not lack FHR-1. Analysis of autoantibody binding to FH19-20 mutants and linear synthetic peptides of the C-terminal FH and FHR-1 domains, as well as reduced FH, revealed differences in the exact binding sites of the autoantibodies. Importantly, all four autoantibodies inhibited C3b binding to FH. In conclusion, our results demonstrate that FH autoantibodies are not uncommon in NMOSD and suggest that generation of antibodies against complement regulating factors among other autoantibodies may contribute to the complement-mediated damage in NMOSD.

Population-based head-to-head comparison of the clinical characteristics and epidemiology of AQP4 antibody-positive NMOSD between two European countries.

BACKGROUND: Population-based clinical studies in neuromyelitis optica spectrum disorder (NMOSD) and epidemiological and clinical comparisons of White ethnicities are missing. In a large population-based international cohort, we extensively characterized aquaporin-4 antibody seropositive (AQP4-Ab+) NMOSD, and also compared the clinical, radiological and epidemiological features between two European populations residing in different areas. METHODS: Between self-reported Danish and Hungarian ethnicities, we compared the population-based clinical features, disability outcomes, and death of 134 AQP4-Ab+ NMOSD cases fulfilling the 2015 International Panel for NMO Diagnosis (IPND) criteria. For precise comparison of epidemiology, we conducted a population-based head-to-head comparative study of the age-standardized prevalence (January 1, 2014) and incidence (2007-2013) of AQP4-Ab+ NMO/NMOSD among adults (≥16 years) in Denmark (4.6 million) and Hungary (6.4 million) by applying 2015 IPND (NMOSD) criteria and 2006 Wingerchuk (NMO). RESULTS: Danes were more likely to present with transverse myelitis and were more affected by spinal cord damage on long-term disability. Hungarians presented most often with optic neuritis, although visual outcome was similar in the groups. No differences were observed in sex, disease course, relapse rate, autoimmune comorbidity, mortality, brain MRI, and treatment strategies. The age-standardized prevalence estimates of AQP4-Ab+ NMOSD (2015 IPND criteria) in Denmark vs. Hungary were 0.66 vs. 1.43 (/100,000) while incidence rates were 0.04 vs. 0.11 (/100,000 person-years); similar differences were found based on the 2006 NMO criteria. CONCLUSIONS: This head-to-head comparative study indicates different disease characteristics and epidemiology among White populations in Europe, and substantiates the need for population-based genetic and environmental studies in NMOSD.

CSF proteome in multiple sclerosis subtypes related to brain lesion transcriptomes.

To identify markers in the CSF of multiple sclerosis (MS) subtypes, we used a two-step proteomic approach: (i) Discovery proteomics compared 169 pooled CSF from MS subtypes and inflammatory/degenerative CNS diseases (NMO spectrum and Alzheimer disease) and healthy controls. (ii) Next, 299 proteins selected by comprehensive statistics were quantified in 170 individual CSF samples. (iii) Genes of the identified proteins were also screened among transcripts in 73 MS brain lesions compared to 25 control brains. F-test based feature selection resulted in 8 proteins differentiating the MS subtypes, and secondary progressive (SP)MS was the most different also from controls. Genes of 7 out these 8 proteins were present in MS brain lesions: GOLM was significantly differentially expressed in active, chronic active, inactive and remyelinating lesions, FRZB in active and chronic active lesions, and SELENBP1 in inactive lesions. Volcano maps of normalized proteins in the different disease groups also indicated the highest amount of altered proteins in SPMS. Apolipoprotein C-I, apolipoprotein A-II, augurin, receptor-type tyrosine-protein phosphatase gamma, and trypsin-1 were upregulated in the CSF of MS subtypes compared to controls. This CSF profile and associated brain lesion spectrum highlight non-inflammatory mechanisms in differentiating CNS diseases and MS subtypes and the uniqueness of SPMS.

Neurofilaments: The C-Reactive Protein of Neurology.

Neurofilaments (NFs) are quickly becoming the biomarkers of choice in the field of neurology, suggesting their use as an unspecific screening marker, much like the use of elevated plasma C-reactive protein (CRP) in other fields. With sensitive techniques being readily available, evidence is growing regarding the diagnostic and prognostic value of NFs in many neurological disorders. Here, we review the latest literature on the structure and function of NFs and report the strengths and pitfalls of NFs as markers of neurodegeneration in the context of neurological diseases of the central and peripheral nervous systems.

Acute Neurofilament Light Chain Plasma Levels Correlate With Stroke Severity and Clinical Outcome in Ischemic Stroke Patients.

Background: Ischemic stroke causes increased blood-brain barrier permeability and release of markers of axonal damage and inflammation. To investigate diagnostic and prognostic roles of neurofilament light chain (NF-L), we assessed levels of NF-L, S100B, interleukin-6 (IL-6), E-selectin, vascular endothelial growth factor-A (VEGF-A), vascular cell adhesion molecule-1 (VCAM-1), and intercellular adhesion molecule-1 (ICAM-1) in patients with acute ischemic stroke or transient ischemic attack (TIA) and healthy controls. Methods: We studied neurofilament (NF) expression in 2 cases of human postmortem ischemic stroke, representing infarcts aged 3- to >7-days. In a prospective study, we measured plasma NF-L and inflammatory markers <8 h of symptom onset and at 72 h in acute ischemic stroke (n = 31), TIA (n = 9), and healthy controls (n = 29). We assessed whether NF-L, S100B, and IL-6 were associated with clinical severity on admission (Scandinavian Stroke Scale, SSS), diagnosis of ischemic stroke vs. TIA, and functional outcome at 3 months (modified Rankin Scale, mRS). Results: NF expression increased in ischemic neurons and in the infarcted brain parenchyma after stroke. Plasma NF-L levels were higher in stroke patients than in TIA patients and healthy controls, but IL-6 levels were similar. Higher acute NF-L levels were associated with lower SSS scores at admission and higher mRS scores at 3 months. No correlation was observed between NF-L and S100B, NF-L and IL-6, nor between S100B or IL-6 and SSS or mRS. Compared to controls, stroke patients had significantly higher VEGF-A and VCAM-1 at <8 h that remained elevated at 72 h, with significantly higher VEGF-A at <8 h; ICAM-1 was significantly increased at <8 h, while S100B and E-selectin were unchanged. Conclusions: Plasma NF-L levels, but not IL-6 and S100B, were significant predictors of clinical severity on admission and functional outcome at 3 months. Plasma NF-L is a promising biomarker of functional outcome after ischemic stroke.

Characterization of the TNF and IL-1 systems in human brain and blood after ischemic stroke.

Preclinical and clinical proof-of-concept studies have suggested the effectiveness of pharmacological modulation of inflammatory cytokines in ischemic stroke. Experimental evidence shows that targeting tumor necrosis factor (TNF) and interleukin (IL)-1 holds promise, and these cytokines are considered prime targets in the development of new stroke therapies. So far, however, information on the cellular expression of TNF and IL-1 in the human ischemic brain is sparse.We studied 14 cases of human post-mortem ischemic stroke, representing 21 specimens of infarcts aged 1 to > 8 days. We characterized glial and leukocyte reactions in the infarct/peri-infarct (I/PI) and normal-appearing tissue (NAT) and the cellular location of TNF, TNF receptor (TNFR)1 and TNFR2, IL-1α, IL-1ß, and IL-1 receptor antagonist (IL-1Ra). The immunohistochemically stained tissue sections received a score reflecting the number of immunoreactive cells and the intensity of the immunoreactivity (IR) in individual cells where 0 = no immunoreactive cells, 1 = many intermediately to strongly immunoreactive cells, and 2 = numerous and intensively immunoreactive cells. Additionally, we measured blood TNF, TNFR, and IL-1 levels in surviving ischemic stroke patients within the first 8 h and again at 72 h after symptom onset and compared levels to healthy controls.We observed IL-1α and IL-1ß IR in neurons, glia, and macrophages in all specimens. IL-1Ra IR was found in glia, in addition to macrophages. TNF IR was initially found in neurons located in I/PI and NAT but increased in glia in older infarcts. TNF IR increased in macrophages in all specimens. TNFR1 IR was found in neurons and glia and macrophages, while TNFR2 was expressed only by glia in I/PI and NAT, and by macrophages in I/PI. Our results suggest that TNF and IL-1 are expressed by subsets of cells and that TNFR2 is expressed in areas with increased astrocytic reactivity. In ischemic stroke patients, we demonstrate that plasma TNFR1 and TNFR2 levels increased in the acute phase after symptom onset compared to healthy controls, whereas TNF, IL-1α, IL-1ß, and IL-1Ra did not change.Our findings of increased brain cytokines and plasma TNFR1 and TNFR2 support the hypothesis that targeting post-stroke inflammation could be a promising add-on therapy in ischemic stroke patients.

Omics-Based Approach Reveals Complement-Mediated Inflammation in Chronic Lymphocytic Inflammation With Pontine Perivascular Enhancement Responsive to Steroids (CLIPPERS).

Objective: Chronic lymphocytic inflammation with pontine perivascular enhancement responsive to steroids (CLIPPERS) is a rare syndrome with relapsing brainstem/cerebellar symptoms. To examine the pathogenic processes and investigate potential biomarkers, we analyzed combined materials of brain and cerebrospinal fluid (CSF) by comprehensive methodologies. Materials and methods: To identify major pathways of perivascular inflammation in CLIPPERS, we first compared the CSF proteome (n = 5) to a neurodegenerative condition, Alzheimer's disease (AD, n = 5). Activation of complement was confirmed by immunohistochemistry (IHC) on CLIPPERS brain samples (n = 3) and by ELISA in the CSF. For potential biomarkers, we used biomarker arrays, and compared inflammatory and vessel-associated proteins in the CSF of CLIPPERS (n = 5) with another inflammatory relapsing CNS disease, multiple sclerosis (RMS, n = 9) and healthy subjects (HS, n = 7). Results: Two hundred and seven proteins in the CSF discriminated CLIPPERS from AD. The complement cascade, immunoglobulins, and matrix proteins were among the most frequently represented pathways. Pathway analysis of upstream regulators suggested the importance of vascular cell adhesion protein 1 (VCAM1), IFN-γ, interleukin (IL)-1, and IL-10. Differential regulation of more than 10 complement proteins of the 3 complement pathways in the CSF pointed to the role of complement activation. IHC on brain samples confirmed the perivascular complement activation, i.e., deposition of C3bc, C3d, and the terminal C5b-9 complement complex that partially overlapped with accumulation of IgG in the vessel wall. Besides endothelial cell damage, reactivity to smooth muscle actin was lost in the walls of inflamed vessels, but the glia limitans was preserved. The semi-quantitative array indicated that increased level of IL-8/CXCL8 (p < 0.05), eotaxin/CCL11 (p < 0.01), and granulocyte colony-stimulating factor (p < 0.05) in CSF could distinguish CLIPPERS from HS. The quantitative array confirmed elevated concentration of IL-8/CXCL8 and eotaxin/CCL11 compared to HS (p < 0.05, respectively) besides increased levels of ICAM-1 (p < 0.05) and VCAM-1 (p < 0.001). The increased concentration of VCAM-1 were able to differentiate CLIPPERS from RMS (p < 0.01), and a trend of elevated levels of ICAM-1 and IL-8/CXCL8 compared to RMS was also observed (p = 0.06, respectively). Conclusion: Complement activation, IgG deposition, and alterations of the extracellular matrix may contribute to inflammation in CLIPPERS. VCAM1, ICAM1, and IL-8 in the CSF may differentiate CLIPPERS from RMS.

Orthologous proteins of experimental de- and remyelination are differentially regulated in the CSF proteome of multiple sclerosis subtypes.

OBJECTIVE: Here, we applied a multi-omics approach (i) to examine molecular pathways related to de- and remyelination in multiple sclerosis (MS) lesions; and (ii) to translate these findings to the CSF proteome in order to identify molecules that are differentially expressed among MS subtypes. METHODS: To relate differentially expressed genes in MS lesions to de- and remyelination, we compared transcriptome of MS lesions to transcriptome of cuprizone (CPZ)-induced de- and remyelination. Protein products of the overlapping orthologous genes were measured within the CSF by quantitative proteomics, parallel reaction monitoring (PRM). Differentially regulated proteins were correlated with molecular markers of inflammation by using MesoScale multiplex immunoassay. Expression kinetics of differentially regulated orthologous genes and proteins were examined in the CPZ model. RESULTS: In the demyelinated and remyelinated corpus callosum, we detected 1239 differentially expressed genes; 91 orthologues were also differentially expressed in MS lesions. Pathway analysis of these orthologues suggested that the TYROBP (DAP12)-TREM2 pathway, TNF-receptor 1, CYBA and the proteasome subunit PSMB9 were related to de- and remyelination. We designed 129 peptides representing 51 orthologous proteins, measured them by PRM in 97 individual CSF, and compared their levels between relapsing (n = 40) and progressive MS (n = 57). Four proteins were differentially regulated among relapsing and progressive MS: tyrosine protein kinase receptor UFO (UFO), TIMP-1, apolipoprotein C-II (APOC2), and beta-2-microglobulin (B2M). The orthologous genes/proteins in the mouse brain peaked during acute remyelination. UFO, TIMP-1 and B2M levels correlated inversely with inflammation in the CSF (IL-6, MCP-1/CCL2, TARC/CCL17). APOC2 showed positive correlation with IL-2, IL-16 and eotaxin-3/CCL26. CONCLUSIONS: Pathology-based multi-omics identified four CSF markers that were differentially expressed in MS subtypes. Upregulated TIMP-1, UFO and B2M orthologues in relapsing MS were associated with reduced inflammation and reflected reparatory processes, in contrast to the upregulated orthologue APOC2 in progressive MS that reflected changes in lipid metabolism associated with increased inflammation.

Toll-like receptor 2 signaling in response to brain injury: an innate bridge to neuroinflammation.

Reactive gliosis is a prominent feature of neurodegenerative and neuroinflammatory disease in the CNS, yet the stimuli that drive this response are not known. There is growing appreciation that signaling through Toll-like receptors (TLRs), which is key to generating innate responses to infection, may have pathogen-independent roles. We show that TLR2 was selectively upregulated by microglia in the denervated zones of the hippocampus in response to stereotactic transection of axons in the entorhinal cortex. In mice lacking TLR2, there were transient, selective reductions in lesion-induced expression of cytokines and chemokines. Recruitment of T cells, but not macrophages, was delayed in TLR2-deficient mice, as well as in mice lacking TNFR1 (tumor necrosis factor receptor 1). TLR2 deficiency also affected microglial proliferative expansion, whereas all of these events were unaffected in TLR4-mutant mice. Consistent with the fact that responses in knock-out mice had all returned to wild-type levels by 8 d, there was no evidence for effects on neuronal plasticity at 20 d. These results identify a role for TLR2 signaling in the early glial response to brain injury, acting as an innate bridge to neuroinflammation.