Is There Reduced Hemodynamic Brain Activation in Multiple Sclerosis Even with Undisturbed Cognition?

Cognitive impairments related to changes in deep gray matter and other brain regions occur in up to 70% of people with multiple sclerosis. But do such brain changes also occur in patients without significant cognitive impairment? Eighteen participants with relapsing-remitting multiple sclerosis (RRMS) and fifteen healthy controls participated in this study. Cognitive status, depression, and fatigue were assessed using the Multiple Sclerosis Inventory of Cognition (MUSIC), Beck's Depression Inventory (BDI-II), and the Fatigue Severity Scale (FSS). fMRI was recorded while a participant performed the modified attention network test (ANT). The effects of ANT executive attention network on hemodynamic activation of a priori defined regions of interest, including the hippocampus, anterior cingulate cortex (ACC), thalamus, caudate nucleus, pallidum, and putamen were studied. The individual lesion load was estimated. For fMRI data analysis a general linear model with randomization statistics including threshold-free cluster enhancement as implemented in the FSL software was used. Participants with RRMS showed reduced activation of the executive attention network in the hippocampus, pallidum, and ACC. The thalamus was involved in both group activations but did not differ between groups. In summary, functional changes in the brain can also be demonstrated in RRMS patients without cognitive deficits. The affected brain regions can best be assigned to the attention network for executive control. This association could likely serve as a biological indicator of susceptibility to imminent cognitive impairment in MS.

Interferon Beta-1a versus Combined Interferon Beta-1a and Oligodendrocyte-Specific FGFR1 Deletion in Experimental Autoimmune Encephalomyelitis.

Recombinant beta interferons-1 (IFNß-1) are used as first line therapies in patients with relapsing multiple sclerosis (MS), a chronic inflammatory and neurodegenerative disease of the CNS. IFNß-1a/b has moderate effects on the prevention of relapses and slowing of disease progression. Fibroblast growth factors (FGFs) and FGF receptors (FGFRs) are known to play a key role in the pathology of MS and its model EAE. To investigate the effects of short-term treatment with s.c. IFNß-1a versus the combined application of s.c. IFNß-1a and oligodendrocyte-specific deletion of FGFR1 (Fgfr1ind-/- mice) in MOG35-55-induced EAE. IFNß-1a (30 mg/kg) was applied s.c. from days 0-7 p.i. of EAE in controls and Fgfr1ind-/- mice. FGFR signaling proteins associated with inflammation/degeneration in MS/EAE were analyzed by western blot in the spinal cord. Further, FGFR1 in Oli-neu oligodendrocytes were inhibited by PD166866 and treated with IFNß-1a (400 ng/mL). Application of IFNß-1a over 8 days resulted in less symptoms only at the peak of disease (days 9-11) compared to controls. Application of IFNß-1a in Fgfr1ind-/- mice resulted in less symptoms primarily in the chronic phase of EAE. Fgfr1ind-/- mice treated with IFNß-1a showed increased expression of pERK and BDNF. In Oli-neu oligodendrocytes, treatment with PD166866 and IFNß-1a also showed an increased expression of pERK and BDNF/TrkB. These data suggest that the beneficial effects in the chronic phase of EAE and on signaling molecules associated with ERK and BDNF expression are caused by the modulation of FGFR1 and not by interferon beta-1a. FGFR may be a potential target for therapy in MS.

Oligodendrocyte-Specific Deletion of FGFR1 Reduces Cerebellar Inflammation and Neurodegeneration in MOG35-55-Induced EAE.

Multiple sclerosis (MS) is a chronic inflammatory and degenerative disease of the central nervous system (CNS). MS commonly affects the cerebellum causing acute and chronic symptoms. Cerebellar signs significantly contribute to clinical disability, and symptoms such as tremor, ataxia, and dysarthria are difficult to treat. Fibroblast growth factors (FGFs) and their receptors (FGFRs) are involved in demyelinating pathologies such as MS. In autopsy tissue from patients with MS, increased expression of FGF1, FGF2, FGF9, and FGFR1 was found in lesion areas. Recent research using mouse models has focused on regions such as the spinal cord, and data on the expression of FGF/FGFR in the cerebellum are not available. In recent EAE studies, we detected that oligodendrocyte-specific deletion of FGFRs results in a milder disease course, less cellular infiltrates, and reduced neurodegeneration in the spinal cord. The objective of this study was to characterize the role of FGFR1 in oligodendrocytes in the cerebellum. Conditional deletion of FGFR1 in oligodendrocytes (Fgfr1ind-/-) was achieved by tamoxifen application, EAE was induced using the MOG35-55 peptide. The cerebellum was analyzed by histology, immunohistochemistry, and western blot. At day 62 p.i., Fgfr1ind-/- mice showed less myelin and axonal degeneration compared to FGFR1-competent mice. Infiltration of CD3(+) T cells, Mac3(+) cells, B220(+) B cells and IgG(+) plasma cells in cerebellar white matter lesions (WML) was less in Fgfr1ind-/-mice. There were no effects on the number of OPC or mature oligodendrocytes in white matter lesion (WML). Expression of FGF2 and FGF9 associated with less myelin and axonal degeneration, and of the pro-inflammatory cytokines IL-1ß, IL-6, and CD200 was downregulated in Fgfr1ind-/- mice. The FGF/FGFR signaling protein pAkt, BDNF, and TrkB were increased in Fgfr1ind-/- mice. These data suggest that cell-specific deletion of FGFR1 in oligodendrocytes has anti-inflammatory and neuroprotective effects in the cerebellum in the EAE disease model of MS.

[Multiple sclerosis treatment consensus group (MSTCG): position paper on disease-modifying treatment of multiple sclerosis 2021 (white paper)]. / Multiple Sklerose Therapie Konsensus Gruppe (MSTKG): Positionspapier zur verlaufsmodifizierenden Therapie der Multiplen Sklerose 2021 (White Paper).

Multiple sclerosis is a complex, autoimmune-mediated disease of the central nervous system characterized by inflammatory demyelination and axonal/neuronal damage. The approval of various disease-modifying therapies and our increased understanding of disease mechanisms and evolution in recent years have significantly changed the prognosis and course of the disease. This update of the Multiple Sclerosis Therapy Consensus Group treatment recommendation focuses on the most important recommendations for disease-modifying therapies of multiple sclerosis in 2021. Our recommendations are based on current scientific evidence and apply to those medications approved in wide parts of Europe, particularly German-speaking countries (Germany, Austria, Switzerland).

The polynucleotide kinase 3'-phosphatase gene (PNKP) is involved in Charcot-Marie-Tooth disease (CMT2B2) previously related to MED25.

Charcot-Marie-Tooth disease (CMT) represents a heterogeneous group of hereditary peripheral neuropathies. We previously reported a CMT locus on chromosome 19q13.3 segregating with the disease in a large Costa Rican family with axonal neuropathy and autosomal recessive pattern of inheritance (CMT2B2). We proposed a homozygous missense variant in the Mediator complex 25 (MED25) gene as causative of the disease. Nevertheless, the fact that no other CMT individuals with MED25 variants were reported to date led us to reevaluate the original family. Using exome sequencing, we now identified a homozygous nonsense variant (p.Gln517ter) in the last exon of an adjacent gene, the polynucleotide kinase 3'-phosphatase (PNKP) gene. It encodes a DNA repair protein recently associated with recessive ataxia with oculomotor apraxia type 4 (AOA4) and microcephaly, seizures, and developmental delay (MCSZ). Subsequently, five unrelated Costa Rican CMT2 subjects initially identified as being heterozygous for the same MED25 variant were found to be also compound heterozygote for PNKP. All were heterozygous for the same variant found homozygous in the large family and a second one previously associated with ataxia (p.Thr408del). Detailed clinical reassessment of the initial family and the new individuals revealed in all an adult-onset slowly progressive CMT2 associated with signs of cerebellar dysfunction such as slurred speech and oculomotor involvement, but neither microcephaly, seizures, nor developmental delay. We propose that PKNP variants are the major causative variant for the CMT2 phenotype in these individuals and that the milder clinical manifestation is due to an allelic effect.

CTRP-3 is permeable to the blood-brain barrier and is not regulated by glucose or lipids in vivo.

BACKGROUND: C1q/TNF-related protein-3 (CTRP-3) represents a novel anti-inflammatory and antidiabetic adipokine secreted by adipose tissue. The physiological and postprandial regulation of CTRP-3 remains obscure and it is not known whether CTRP-3 is permeable to the brain. The postprandial regulation of CTRP-3 during an oral glucose tolerance test (n = 100) and an oral lipid tolerance test (n = 100) in humans was investigated. Moreover, CTRP-3 concentrations were measured in paired serum and cerebrospinal fluid (CSF) samples of patients (n = 270) undergoing neurological evaluation. The expression of CTRP-3 mRNA was investigated in adipocytes upon stimulation with glucose, sex hormones and a broad panel of fatty acids. MATERIALS AND METHODS: Serum and CSF CTRP-3 concentrations were measured by ELISA. 3T3-L1 adipocytes were used for stimulation experiments. CTRP-3 mRNA expression was quantified by using real-time PCR analysis. RESULTS: CTRP-3 is present in human cerebrospinal fluid with a mean CSF/serum ratio of 110 ± 64 × 10-3 . CTRP-3 is not regulated postprandially by carbohydrates or lipids in the healthy state. Females have slightly higher levels of CTRP-3 when compared to males. A significant and positive correlation of CTRP-3 to LDL cholesterol serum levels is reproducible in several cohorts and deserves further mechanistic investigation. Whereas glucose concentrations do not influence CTRP-3 mRNA expression in 3T3-L1 adipocytes in vitro, fatty acids differentially modulate CTRP-3 expression. CONCLUSIONS: The novel adipokine CTRP-3 is detectable in human cerebrospinal fluid (proof of principle). Due to its blood-brain barrier permeability, CTRP-3 represents a novel putative candidate for a physiological regulator molecule affecting central nervous functions.

Quantification and regulation of adipsin in human cerebrospinal fluid (CSF).

CONTEXT: Data on quantification and regulation of adipsin in human cerebrospinal fluid (CSF) are sparse, and the physiological role of adipsin as an adipokine crossing the blood-brain barrier (BBB) is uncertain. OBJECTIVES: This study quantified adipsin concentrations in paired serum and CSF samples of patients undergoing neurological evaluation and spinal puncture. DESIGN: A total of 270 consecutive patients with specified neurological diagnosis were included in this study without prior selection. MAIN OUTCOME MEASURES: Adipsin serum and CSF concentrations were measured by ELISA. A variety of serum and CSF routine parameters were measured by standard procedures. Anthropometric data, medication and patient history were available. RESULTS: Adipsin concentrations ranged between 467 and 5148 ng/ml in serum and between 4·2 and 133·5 ng/ml in CSF. Serum adipsin concentrations were correlated positively with respective CSF concentrations and were approximately 40-fold higher when compared to CSF. The mean CSF/serum ratio for adipsin was 27 ± 22 × 10-3 . Serum and CSF adipsin levels were independent of gender and significantly higher in overweight/obese individuals. Serum and CSF adipsin levels correlated significantly with age and were higher in patients suffering from diabetes mellitus or hypertension. CSF adipsin concentrations showed a significant correlation with markers of inflammation in CSF, but not with CSF total cell count or the presence of oligoclonal bands. Patients suffering from infectious diseases had higher CSF levels of adipsin than multiple sclerosis patients. CONCLUSIONS: Adipsin is present in human CSF under pathophysiological conditions. The positive correlation between serum and CSF concentrations, the positive correlation between the CSF/serum ratios for adipsin and total protein and the lack of association with CSF cell count argue against an autochthonous production in the central nervous system. In contrast, the present data argue for a significant BBB permeability to adipsin.

Quantification and regulation of the adipokines resistin and progranulin in human cerebrospinal fluid.

BACKGROUND: Adipokines bearing the potential to cross the blood-brain barrier (BBB) are promising candidates for the endocrine regulation of central nervous processes and of a postulated fat-brain axis. Resistin and progranulin concentrations in paired serum and cerebrospinal fluid (CSF) samples of patients undergoing neurological evaluation and spinal puncture were investigated. MATERIALS AND METHODS: Samples of n = 270 consecutive patients with various neurological diseases were collected without prior selection. Adipokine serum and CSF concentrations were measured by enzyme-linked immunosorbent assay and serum and CSF routine parameters by standard procedures. Anthropometric data, medication and patient history were available. RESULTS: Serum levels of resistin and progranulin were positively correlated among each other, with respective CSF levels, low-density lipoprotein cholesterol levels and markers of systemic inflammation. CSF resistin concentrations were generally low. Progranulin CSF concentrations and CSF/serum progranulin ratio were significantly higher in patients with infectious diseases, with disturbed BBB function and with elevated CSF cell count and presence of oligoclonal bands. Both adipokines are able to cross the BBB depending on a differing patency that increases with increasing grade of barrier dysfunction. Whereas resistin represents a systemic marker of inflammation, CSF progranulin levels strongly depend on the underlying disease and dysfunction of blood-CSF barrier. CONCLUSIONS: Resistin and progranulin represent novel and putative regulators of the fat-brain axis by their ability to cross the BBB under physiological and pathophysiological conditions. The presented data provide insight into the characteristics of BBB function regarding progranulin and resistin and the basis for future establishment of normal values for CSF concentrations and CSF/serum ratios.

Evidence-based patient information programme in early multiple sclerosis: a randomised controlled trial.

OBJECTIVE: To evaluate the efficacy of an evidence-based patient information programme aiming to increase informed choice in patients with early multiple sclerosis (MS). BACKGROUND: Patients with early MS face a number of uncertainties concerning diagnosis, prognosis and effectiveness of immunotherapy. Prior studies suggest that evidence-based patient information combined with group education can promote informed choice in MS patients. METHODS: A 12-month, six-centre, double-blind randomised controlled clinical trial with 192 patients with a diagnosis of confirmed relapsing-remitting MS or clinical isolated syndrome in Germany. A 4-h interactive evidence-based educational programme was compared with a 4-h MS-specific stress management programme. The primary endpoint was informed choice after 6 months comprising risk knowledge and congruency between attitude towards immunotherapy and actual immunotherapy uptake. Secondary endpoints included autonomy preference, decision autonomy, decisional conflict and satisfaction, anxiety and depression, and number of immunotherapies. RESULTS: For the primary endpoint, a significant difference was shown with 50 of 85 (59%) participants in the intervention group achieving informed choice after 6 months compared with 18 of 89 (20%) in the control group (OR 0.2 (95% CI 0.1 to 0.4), p<0.001). Four weeks after the intervention, more participants in the intervention group showed good risk knowledge (difference between groups 39% (95% CI 26% to 53%), p<0.001). There were no significant differences between groups for attitude towards immunotherapy and for immunotherapy uptake. There were trends towards increased autonomy preference after the intervention and increased adherence to immunotherapies in the intervention group. CONCLUSIONS: The intervention significantly increased informed choice and relevant risk knowledge without negative side effects.

A Costa Rican family affected with Charcot-Marie-Tooth disease due to the myelin protein zero (MPZ) p.Thr124Met mutation shares the Belgian haplotype.

The p.Thr124Met mutation in the myelin protein zero (MPZ) causes the Charcot-Marie-Tooth disease type 2J, a peripheral neuropathy with additional symptoms as pupillary alterations and deafness. It was observed in several families around the world originating e. g. from Germany, Belgium, Japan, Italy and North America. Here we report Central American patients originating from a family in Costa Rica carrying this mutation. Clinical, electrophysiological and molecular analysis of patients and controls were performed, including gene and linked markers' sequencing. Carriers share almost the entire haplotype with two non related Belgian CMT patients. As a result of the haplotype analysis, based on ten markers (seven SNPs, two microsatellites and an intronic polyA stretch), the founder effect hypothesis for this allele migration is suggestive.

The small molecule fibroblast growth factor receptor inhibitor infigratinib exerts anti-inflammatory effects and remyelination in a model of multiple sclerosis.

BACKGROUND AND PURPOSE: Fibroblast growth factors and receptors (FGFR) have been shown to modulate inflammation and neurodegeneration in multiple sclerosis (MS). The selective FGFR inhibitor infigratinib has been shown to be effective in cancer models. Here, we investigate the effects of infigratinib on prevention and suppression of first clinical episodes of myelin oligodendrocyte glycoprotein (MOG)35-55 -induced experimental autoimmune encephalomyelitis (EAE) in mice. EXPERIMENTAL APPROACH: The FGFR inhibitor infigratinib was given over 10 days from the time of experimental autoimmune encephalomyelitis induction or the onset of symptoms. The effects of infigratinib on proliferation, cytotoxicity and FGFR signalling proteins were studied in lymphocyte cell lines and microglial cells. KEY RESULTS: Administration of infigratinib prevented by 40% and inhibited by 65% first clinical episodes of the induced experimental autoimmune encephalomyelitis. In the spinal cord, infiltration of lymphocytes and macrophages/microglia, destruction of myelin and axons were reduced by infigratinib. Infigratinib enhanced the maturation of oligodendrocytes and increased remyelination. In addition, infigratinib resulted in an increase of myelin proteins and a decrease in remyelination inhibitors. Further, lipids associated with neurodegeneration such as lysophosphatidylcholine and ceramide were decreased as were proliferation of T cells and microglial cells. CONCLUSION AND IMPLICATIONS: This proof of concept study demonstrates the therapeutic potential of targeting FGFRs in a disease model of multiple sclerosis. Application of oral infigratinib resulted in anti-inflammatory and remyelinating effects. Thus, infigratinib may have the potential to slow disease progression or even to improve the disabling symptoms of multiple sclerosis.

Decline in the number of patients with meningitis in German hospitals during the COVID-19 pandemic.

BACKGROUND AND OBJECTIVES: In 2020, a wide range of hygiene measures was implemented to mitigate infections caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). In consequence, pulmonary infections due to other respiratory pathogens also decreased. Here, we evaluated the number of bacterial and viral meningitis and encephalitis cases during the coronavirus disease 2019 (COVID-19) pandemic. METHODS: In a multicentre retrospective analysis of data from January 2016 until December 2020, numbers of patients diagnosed with bacterial meningitis and other types of CNS infections (such as viral meningitis and encephalitis) at 26 German hospitals were studied. Furthermore, the number of common meningitis-preceding ear-nose-throat infections (sinusitis, mastoiditis and otitis media) was evaluated. RESULTS: Compared to the previous years, the total number of patients diagnosed with pneumococcal meningitis was reduced (n = 64 patients/year in 2020 vs. n = 87 to 120 patients/year between 2016 and 2019, all p < 0.05). Additionally, the total number of patients diagnosed with otolaryngological infections was significantly lower (n = 1181 patients/year in 2020 vs. n = 1525 to 1754 patients/year between 2016 and 2019, all p < 0.001). We also observed a decline in viral meningitis and especially enterovirus meningitis (n = 25 patients/year in 2020 vs. n = 97 to 181 patients/year between 2016 and 2019, all p < 0.001). DISCUSSION: This multicentre retrospective analysis demonstrates a decline in the number of patients treated for viral and pneumococcal meningitis as well as otolaryngological infections in 2020 compared to previous years. Since the latter often precedes pneumococcal meningitis, this may point to the significance of the direct spread of pneumococci from an otolaryngological focus such as mastoiditis to the brain as one important pathophysiological route in the development of pneumococcal meningitis.

Effects of the CC chemokine receptor 2 in mice deficient for the myelin protein zero (P0).

In myelin protein zero (P0)-deficient mice immune cells are critically involved in the pathogenesis of a primary genetic disease. Previously it has been shown that the chemokine CCL2 affects the functional properties of endoneurial macrophages in heterozygous P0 mice. The aim of the present study was to characterize the role of the CCL2-receptor CCR2 in the pathogenesis of the neuropathy in P0 deficient mice. In demyelinating nerves of heterozygous P0 mice (P0+/-) CCR2-deficiency did not affect the number of endoneurial macrophages; there was a trend towards a higher number of activated macrophages. CCR2-deficiency resulted in an increased nerve demyelination. In dysmyelinating nerves of homozygous P0 mice (P0-/-), CCR2-deficiency led to a significant decrease of endoneurial macrophages but did not affect axonal degeneration. There was no effect of CCR2 on T-lymphocytes in both disease models. Our data confirm a functional role of the CCR2 receptor in the examined models of hereditary neuropathies. In P0+/- mutants CCR2 decreases macrophage activation and is protective against demyelination, whereas in P0-/- mice it increases the accumulation of endoneurial macrophages.

Systematic Quantification of Neurotrophic Adipokines RBP4, PEDF, and Clusterin in Human Cerebrospinal Fluid and Serum.

CONTEXT: Data on the presence/quantification of the neurotrophic adipokines retinol-binding protein-4 (RBP4), clusterin, and pigment epithelium-derived factor (PEDF) in human cerebrospinal fluid (CSF) are scarce and migration of these adipokines across of the blood-brain barrier (BBB) is uncertain. OBJECTIVE: This work aimed to quantify RBP4, PEDF, and clusterin in paired serum and CSF samples of patients undergoing neurological evaluation. METHODS: A total of 268 patients (109 male, 159 female) were included. Adipokine serum and CSF concentrations were measured by enzyme-linked immunosorbent assay in duplicate. RESULTS: RBP4 was abundant in serum (mean, 31.9 ±â€…24.2 µg/mL). The serum concentrations were approximately 145 times higher than in CSF (CSF to serum RBP4 ratio, 8.2 ±â€…4.3 × 10-3). PEDF was detectable in serum (mean, 30.2 ±â€…11.7 µg/mL) and concentrations were approximately 25 times higher than in CSF (CSF to serum PEDF ratio, 42.3 ±â€…15.6 × 10-3). Clusterin serum concentrations were abundant with mean levels of 346.0 ±â€…114.6 µg/mL, which were approximately 40 times higher than CSF levels (CSF to serum clusterin ratio, 29.6 ±â€…23.4 × 10-3). RBP4 and PEDF serum levels correlated positively with CSF levels, which were increased in overweight/obese patients and in type 2 diabetic patients. The CSF concentrations of all 3 adipokines increased with BBB dysfunction. RBP4 in CSF correlated positively with inflammatory parameters. In detail, only RBP4 showed the kinetics and associations that are mandatory for a putative mediator of the fat-brain axis. CONCLUSION: RBP4, PEDF, and clusterin are permeable to the BBB and increase with the measure of BBB dysfunction. RBP4 represents an inflammatory neurotrophic adipokine and is a promising mediator of the fat-brain axis.

FGF/FGFR Pathways in Multiple Sclerosis and in Its Disease Models.

Multiple sclerosis (MS) is a chronic inflammatory and neurodegenerative disease of the central nervous system (CNS) affecting more than two million people worldwide. In MS, oligodendrocytes and myelin sheaths are destroyed by autoimmune-mediated inflammation, while remyelination is impaired. Recent investigations of post-mortem tissue suggest that Fibroblast growth factor (FGF) signaling may regulate inflammation and myelination in MS. FGF2 expression seems to correlate positively with macrophages/microglia and negatively with myelination; FGF1 was suggested to promote remyelination. In myelin oligodendrocyte glycoprotein (MOG)35-55-induced experimental autoimmune encephalomyelitis (EAE), systemic deletion of FGF2 suggested that FGF2 may promote remyelination. Specific deletion of FGF receptors (FGFRs) in oligodendrocytes in this EAE model resulted in a decrease of lymphocyte and macrophage/microglia infiltration as well as myelin and axon degeneration. These effects were mediated by ERK/Akt phosphorylation, a brain-derived neurotrophic factor, and downregulation of inhibitors of remyelination. In the first part of this review, the most important pharmacotherapeutic principles for MS will be illustrated, and then we will review recent advances made on FGF signaling in MS. Thus, we will suggest application of FGFR inhibitors, which are currently used in Phase II and III cancer trials, as a therapeutic option to reduce inflammation and induce remyelination in EAE and eventually MS.

Evidence of a Muscle-Brain Axis by Quantification of the Neurotrophic Myokine METRNL (Meteorin-Like Protein) in Human Cerebrospinal Fluid and Serum.

Data on the quantification of the potentially neurotrophic adipo-myokine METRNL (Meteorin-like protein) in human cerebrospinal fluid (CSF) are lacking and migration of this secreted protein across the blood-brain barrier (BBB) is uncertain. In the present pilot study, METRNL concentrations were quantified by ELISA in paired serum and CSF samples of 260 patients (107 males, 153 females) undergoing neurological evaluation. METRNL was abundant in serum (801.2 ± 378.3 pg/mL) and CSF (1007.2 ± 624.2 pg/mL) with a CSF/serum ratio of 1.4 ± 0.8. Serum METRNL levels were significantly correlated (rho = +0.521) to those in CSF. CSF METRNL concentrations were significantly correlated (rho = +0.480) with albumin CSF/serum ratios. The CSF/serum ratios of METRNL and albumin were positively correlated in Reibergram analysis (rho = 0.498), indicating that raising CSF concentrations of METRNL are mediated by increasing BBB dysfunction. The CSF concentrations of METRNL strongly increased in a stepwise manner along with increasing BBB dysfunction from grade 0 to grade 3 and with rising CSF cell count. CSF/serum ratio of METRNL also increased from grade 0 (1.2 ± 0.7) to grade 3 (3.0 ± 0.2). Furthermore, CSF levels were positively correlated with age. In conclusion, METRNL is a secreted and neurotrophic myokine that crosses over the BBB. CSF concentrations of METRNL increase with BBB dysfunction.

Oligodendrocyte-specific deletion of FGFR2 ameliorates MOG35-55 -induced EAE through ERK and Akt signalling.

Fibroblast growth factors (FGFs) and their receptors (FGFRs) are involved in demyelinating pathologies including multiple sclerosis (MS). In our recent study, oligodendrocyte-specific deletion of FGFR1 resulted in a milder disease course, less inflammation, reduced myelin and axon damage in EAE. The objective of this study was to elucidate the role of oligodendroglial FGFR2 in MOG35-55 -induced EAE. Oligodendrocyte-specific knockout of FGFR2 (Fgfr2ind-/- ) was achieved by application of tamoxifen; EAE was induced using the MOG35-55 peptide. EAE symptoms were monitored over 62 days. Spinal cord tissue was analysed by histology, immunohistochemistry and western blot. Fgfr2ind-/- mice revealed a milder disease course, less myelin damage and enhanced axonal density. The number of oligodendrocytes was not affected in demyelinated areas. However, protein expression of FGFR2, FGF2 and FGF9 was downregulated in Fgfr2ind-/- mice. FGF/FGFR dependent signalling proteins were differentially regulated; pAkt was upregulated and pERK was downregulated in Fgfr2ind-/- mice. The number of CD3(+) T cells, Mac3(+) cells and B220(+) B cells was less in demyelinated lesions of Fgfr2ind-/-  mice. Furthermore, expression of IL-1ß, TNF-α and CD200 was less in Fgfr2ind-/-  mice than controls. Fgfr2ind-/-  mice showed an upregulation of PLP and downregulation of the remyelination inhibitors SEMA3A and TGF-ß expression. These data suggest that cell-specific deletion of FGFR2 in oligodendrocytes has anti-inflammatory and neuroprotective effects accompanied by changes in FGF/FGFR dependent signalling, inflammatory cytokines and expression of remyelination inhibitors. Thus, FGFRs in oligodendrocytes may represent potential targets for the treatment of inflammatory and demyelinating diseases including MS.

Effects of FGFR Tyrosine Kinase Inhibition in OLN-93 Oligodendrocytes.

Fibroblast growth factor (FGF) signaling is involved in the pathogenesis of multiple sclerosis (MS). Data from neuropathology studies suggest that FGF signaling contributes to the failure of remyelination in MS. In MOG35-55-induced EAE, oligodendrocyte-specific deletion of FGFR1 and FGFR2 resulted in a less severe disease course, reduced inflammation, myelin and axon degeneration and changed FGF/FGFR and BDNF/TrkB signaling. Since signaling cascades in oligodendrocytes could not be investigated in the EAE studies, we here aimed to characterize FGFR-dependent oligodendrocyte-specific signaling in vitro. FGFR inhibition was achieved by application of the multi-kinase-inhibitor dovitinib and the FGFR1/2/3-inhibitor AZD4547. Both substances are potent inhibitors of FGF signaling; they are effective in experimental tumor models and patients with malignancies. Effects of FGFR inhibition in oligodendrocytes were studied by immunofluorescence microscopy, protein and gene analyses. Application of the tyrosine kinase inhibitors reduced FGFR1, phosphorylated ERK and Akt expression, and it enhanced BDNF and TrkB expression. Furthermore, the myelin proteins CNPase and PLP were upregulated by FGFR inhibition. In summary, inhibition of FGFR signaling in oligodendrocytes can be achieved by application of tyrosine kinase inhibitors. Decreased phosphorylation of ERK and Akt is associated with an upregulation of BDNF/TrkB signaling, which may be responsible for the increased production of myelin proteins. Furthermore, these data suggest that application of FGFR inhibitors may have the potential to promote remyelination in the CNS.

Multiple Sclerosis Therapy Consensus Group (MSTCG): position statement on disease-modifying therapies for multiple sclerosis (white paper).

Multiple sclerosis is a complex, autoimmune-mediated disease of the central nervous system characterized by inflammatory demyelination and axonal/neuronal damage. The approval of various disease-modifying therapies and our increased understanding of disease mechanisms and evolution in recent years have significantly changed the prognosis and course of the disease. This update of the Multiple Sclerosis Therapy Consensus Group treatment recommendation focuses on the most important recommendations for disease-modifying therapies of multiple sclerosis in 2021. Our recommendations are based on current scientific evidence and apply to those medications approved in wide parts of Europe, particularly German-speaking countries (Germany, Austria, and Switzerland).

Identification of the variant Ala335Val of MED25 as responsible for CMT2B2: molecular data, functional studies of the SH3 recognition motif and correlation between wild-type MED25 and PMP22 RNA levels in CMT1A animal models.

Charcot-Marie-Tooth (CMT) disease is a clinically and genetically heterogeneous disorder. All mendelian patterns of inheritance have been described. We identified a homozygous p.A335V mutation in the MED25 gene in an extended Costa Rican family with autosomal recessively inherited Charcot-Marie-Tooth neuropathy linked to the CMT2B2 locus in chromosome 19q13.3. MED25, also known as ARC92 and ACID1, is a subunit of the human activator-recruited cofactor (ARC), a family of large transcriptional coactivator complexes related to the yeast Mediator. MED25 was identified by virtue of functional association with the activator domains of multiple cellular and viral transcriptional activators. Its exact physiological function in transcriptional regulation remains obscure. The CMT2B2-associated missense amino acid substitution p.A335V is located in a proline-rich region with high affinity for SH3 domains of the Abelson type. The mutation causes a decrease in binding specificity leading to the recognition of a broader range of SH3 domain proteins. Furthermore, Med25 is coordinately expressed with Pmp22 gene dosage and expression in transgenic mice and rats. These results suggest a potential role of this protein in the molecular etiology of CMT2B2 and suggest a potential, more general role of MED25 in gene dosage sensitive peripheral neuropathy pathogenesis.