An IL-5 Single-Nucleotide Polymorphism Influences Neuroinflammation and Prospective Disease Activity in Multiple Sclerosis.

(1) Multiple sclerosis (MS) is identified by a complex interaction between central inflammation and neurodegeneration. Genetic individual variability could play a significative role in clinical presentation. The interleukin-5 (IL-5) rs2069812 single-nucleotide polymorphism (SNP) seems to define the clinical course of Th2 autoimmune diseases, while its role in MS has never been investigated. (2) In a group of 230 patients diagnosed with relapsing-remitting MS (RR-MS) or progressive MS (P-MS) and controls (IC), rs2069812 polymorphism, cerebrospinal fluid (CSF) levels of inflammatory mediators, and clinical and demographic characteristics were determined. In RR-MS patients, No Evidence of Disease Activity (NEDA-3) at three years of follow-up was detected. (3) We identified higher levels of proinflammatory cytokines, particularly IL-2 (median [IQR], RR-MS = 0.2 [0-0.7]; P-MS = 0.1 [0-1.6]; IC = 0.1 [0.0-0.1]; p < 0.005), IL-6 (RR-MS = 0.9 [0.3-2.3]; P-MS = 0.8 [0.1-2.7]; IC = 0.1 [0.0-0.5]; p < 0.005), IL-12 (RR-MS = 0.5 [0-1.1]; P-MS = 0.5 [0-1.1]; IC = 0.0 [0.0-0.3]; p < 0.005), and GM-CSF (RR-MS = 15.6 [4.8-26.4]; P-MS = 14 [3.3-29.7]; IC = 8.9 [4.7-11.7]; p < 0.005) in MS patients compared with IC. Conversely, anti-inflammatory cytokines, specifically IL-5 (RR-MS = 0.65 [0-2.4]; P-MS = 0.1 [0-0.8]; IC = 1.7 [0.6-2.8]; p < 0.005) and IL-1ra (RR-MS = 14.7 [4.9-26.4]; P-MS = 13.1 [4.7-22.2]; IC = 27.8 [17.7-37.6]; p < 0.005) were higher in controls. According to rs2069812, in MS patients, the T-allele was associated with higher concentrations of proinflammatory mediators (IL-2, CT/TT = 0.2 [0.0-2.0]; CC = 0.1 [0.0-0.4], p = 0.015; IL-6, CT/TT = 1.2 [0.4-3.2] vs. CC = 0.7 [0.1-1.7], p = 0.007; IL-15, CT/TT = 0.1 [0.0-9.5] vs. CC = 0.0 [0.0-0.1], p = 0.019; and GM-CSF, CT/TT = 0.1 [0.0-0.6] vs. CC = 0.05 [0.0-0.1], p < 0.001), and CC was associated with anti-inflammatory mediators (IL-5, CT/TT = 0.03 [0.0-1.9] vs. CC = 1.28 [0.0-2.7], p = 0.001; IL-1ra, CT/TT = 12.1 [4.1-25.9] vs. CC = 18.1 [12.1-26.9], p = 0.006). We found the same differences in RR-MS patients (IL-2, T-allele median [IQR] = 0.3 [0.0-2.0] vs. C-allele, median [IQR] = 0.04 [0.0-0.3]; p = 0.005; IL-6, T-allele, median [IQR] = 1.3 [0.4-3.3] vs. C-allele, median [IQR] = 0.6 [0.03-1.5]; p = 0.001; IL-15, T-allele, median [IQR] = 0.1 [0.0-9.5] vs. C-allele, median [IQR] = 0.0 [0.0-0.1]; p = 0.008; GM-CSF, T-allele, median [IQR] = 0.1 [0.0-97.9] vs. C-allele, median [IQR] = 0.0 [0.0-0.001]; p < 0.001; IL-5, T-allele, median [IQR] = 0.02 [0.0-2.2] vs. C-allele, median [IQR] = 1.5 [0.0-2.9]; p = 0.016; and IL-1ra, T-allele, median [IQR] = 12.1 [4.3-26.4] vs. C-allele, median [IQR] = 18.5 [12.7-28.3]; p = 0.006) but not in P-MS, except for IL-5 (T-allele, median [IQR] = 0.1 [0-0.23] vs. C-allele, median [IQR] = 0.6 [0.0-2.5]; p = 0.022). Finally, we identified an association between CC in RR-MS patients and NEDA-3 after three years of follow-up (p = 0.007). (4) We describe, for the first time, the role of an SNP of the IL-5 gene in regulating central neuroinflammation and influencing clinical course in MS patients.

Cortical plasticity in AQP4-positive NMOSD: a transcranial magnetic stimulation study.

Aquaporin-4 antibody-positive neuromyelitis optica spectrum disorder (AQP4-NMOSD) is an autoimmune disease characterized by suboptimal recovery from attacks and long-term disability. Experimental data suggest that AQP4 antibodies can disrupt neuroplasticity, a fundamental driver of brain recovery. A well-established method to assess brain LTP is through intermittent theta-burst stimulation (iTBS). This study aimed to explore neuroplasticity in AQP4-NMOSD patients by examining long-term potentiation (LTP) through iTBS. We conducted a proof-of-principle study including 8 patients with AQP4-NMOSD, 8 patients with multiple sclerosis (MS), and 8 healthy controls (HC) in which iTBS was administered to induce LTP-like effects. iTBS-induced LTP exhibited significant differences among the 3 groups (p: 0.006). Notably, AQP4-NMOSD patients demonstrated impaired plasticity compared to both HC (p = 0.01) and pwMS (p = 0.02). This pilot study provides the first in vivo evidence supporting impaired neuroplasticity in AQP4-NMOSD patients. Impaired cortical plasticity may hinder recovery following attacks suggesting a need for targeted rehabilitation strategies.

Interleukin-10 contrasts inflammatory synaptopathy and central neurodegenerative damage in multiple sclerosis.

Proinflammatory cytokines are implicated in promoting neurodegeneration in multiple sclerosis (MS) by affecting excitatory and inhibitory transmission at central synapses. Conversely, the synaptic effects of anti-inflammatory molecules remain underexplored, despite their potential neuroprotective properties and their presence in the cerebrospinal fluid (CSF) of patients. In a study involving 184 newly diagnosed relapsing-remitting (RR)-MS patients, we investigated whether CSF levels of the anti-inflammatory interleukin (IL)-10 were linked to disease severity and neurodegeneration measures. Additionally, we examined IL-10 impact on synaptic transmission in striatal medium spiny neurons and its role in counteracting inflammatory synaptopathy induced by IL-1ß in female C57BL/6 mice with experimental autoimmune encephalomyelitis (EAE). Our findings revealed a significant positive correlation between IL-10 CSF levels and changes in EDSS (Expanded Disability Status Scale) scores one year after MS diagnosis. Moreover, IL-10 levels in the CSF were positively correlated with volumes of specific subcortical brain structures, such as the nucleus caudate. In both MS patients' CSF and EAE mice striatum, IL-10 and IL-1ß expressions were upregulated, suggesting possible antagonistic effects of these cytokines. Notably, IL-10 exhibited the ability to decrease glutamate transmission, increase GABA transmission in the striatum, and reverse IL-1ß-induced abnormal synaptic transmission in EAE. In conclusion, our data suggest that IL-10 exerts direct neuroprotective effects in MS patients by modulating both excitatory and inhibitory transmission and attenuating IL-1ß-induced inflammatory synaptopathy. These findings underscore the potential therapeutic significance of IL-10 in mitigating neurodegeneration in MS.

Inflammatory signature in amyotrophic lateral sclerosis predicting disease progression.

Experimental studies identified a role of neuroinflammation in the pathogenesis of neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). However, the role of inflammatory molecules as diagnostic and prognostic biomarkers in patients with ALS is unclear. In this cross-sectional study, the cerebrospinal fluid (CSF) levels of a set of inflammatory cytokines and chemokines were analyzed in 56 newly diagnosed ALS patients and in 47 age- and sex-matched control patients without inflammatory or degenerative neurological disorders. The molecules analyzed included: interleukin (IL)-1ß, IL-2, IL-4, IL-5, IL-6, IL-7, IL-8, IL-9, IL-10, IL-12, IL-13, IL-17, granulocyte colony stimulating factor (GCSF), macrophage inflammatory protein (MIP)-1a, MIP-1b, tumor necrosis factors (TNF), eotaxin. Principal component analysis (PCA) was used to explore possible associations between CSF molecules and ALS diagnosis. In addition, we analyzed the association between CSF cytokine profiles and clinical characteristics, including the disease progression rate score, and peripheral inflammation assessed using the Neutrophil-to-lymphocyte ratio (NLR). PCA identified six principal components (PCs) explaining 70.67% of the total variance in the CSF cytokine set. The principal component (PC1) explained 26.8% of variance and showed a positive load with CSF levels of IL-9, IL-4, GCSF, IL-7, IL-17, IL-13, IL-6, IL-1ß, TNF, and IL-2. Logistic regression showed a significant association between PC1 and ALS diagnosis. In addition, in ALS patients, the same component was significantly associated with higher disease progression rate score and positively correlated with NLR. CSF inflammatory activation in present in ALS at the time of diagnosis and may characterize patients at higher risk for disease progression.

Re-emergence of T lymphocyte-mediated synaptopathy in progressive multiple sclerosis.

Background: Secondary progressive multiple sclerosis (SPMS) is defined by the irreversible accumulation of disability following a relapsing-remitting MS (RRMS) course. Despite treatments advances, a reliable tool able to capture the transition from RRMS to SPMS is lacking. A T cell chimeric MS model demonstrated that T cells derived from relapsing patients exacerbate excitatory transmission of central neurons, a synaptotoxic event absent during remitting stages. We hypothesized the re-emergence of T cell synaptotoxicity during SPMS and investigated the synaptoprotective effects of siponimod, a sphingosine 1-phosphate receptor (S1PR) modulator, known to reduce grey matter damage in SPMS patients. Methods: Data from healthy controls (HC), SPMS patients, and siponimod-treated SPMS patients were collected. Chimeric experiments were performed incubating human T cells on murine cortico-striatal slices, and recording spontaneous glutamatergic activity from striatal neurons. Homologous chimeric experiments were executed incubating EAE mice T cells with siponimod and specific S1PR agonists or antagonists to identify the receptor involved in siponimod-mediated synaptic recovery. Results: SPMS patient-derived T cells significantly increased the striatal excitatory synaptic transmission (n=40 synapses) compared to HC T cells (n=55 synapses), mimicking the glutamatergic alterations observed in active RRMS-T cells. Siponimod treatment rescued SPMS T cells synaptotoxicity (n=51 synapses). Homologous chimeric experiments highlighted S1P5R involvement in the siponimod's protective effects. Conclusion: Transition from RRMS to SPMS involves the reappearance of T cell-mediated synaptotoxicity. Siponimod counteracts T cell-induced excitotoxicity, emphasizing the significance of inflammatory synaptopathy in progressive MS and its potential as a promising pharmacological target.

Interleukin-9 protects from microglia- and TNF-mediated synaptotoxicity in experimental multiple sclerosis.

BACKGROUND: Multiple sclerosis (MS) is a progressive neurodegenerative disease of the central nervous system characterized by inflammation-driven synaptic abnormalities. Interleukin-9 (IL-9) is emerging as a pleiotropic cytokine involved in MS pathophysiology. METHODS: Through biochemical, immunohistochemical, and electrophysiological experiments, we investigated the effects of both peripheral and central administration of IL-9 on C57/BL6 female mice with experimental autoimmune encephalomyelitis (EAE), a model of MS. RESULTS: We demonstrated that both systemic and local administration of IL-9 significantly improved clinical disability, reduced neuroinflammation, and mitigated synaptic damage in EAE. The results unveil an unrecognized central effect of IL-9 against microglia- and TNF-mediated neuronal excitotoxicity. Two main mechanisms emerged: first, IL-9 modulated microglial inflammatory activity by enhancing the expression of the triggering receptor expressed on myeloid cells-2 (TREM2) and reducing TNF release. Second, IL-9 suppressed neuronal TNF signaling, thereby blocking its synaptotoxic effects. CONCLUSIONS: The data presented in this work highlight IL-9 as a critical neuroprotective molecule capable of interfering with inflammatory synaptopathy in EAE. These findings open new avenues for treatments targeting the neurodegenerative damage associated with MS, as well as other inflammatory and neurodegenerative disorders of the central nervous system.

Interaction between miR-142-3p and BDNF Val/Met Polymorphism Regulates Multiple Sclerosis Severity.

MiR-142-3p has recently emerged as key factor in tailoring personalized treatments for multiple sclerosis (MS), a chronic autoimmune demyelinating disease of the central nervous system (CNS) with heterogeneous pathophysiology and an unpredictable course. With its involvement in a detrimental regulatory axis with interleukin-1beta (IL1ß), miR-142-3p orchestrates excitotoxic synaptic alterations that significantly impact both MS progression and therapeutic outcomes. In this study, we investigated for the first time the influence of individual genetic variability on the miR-142-3p excitotoxic effect in MS. We specifically focused on the single-nucleotide polymorphism Val66Met (rs6265) of the brain-derived neurotrophic factor (BDNF) gene, known for its crucial role in CNS functioning. We assessed the levels of miR-142-3p and IL1ß in cerebrospinal fluid (CSF) obtained from a cohort of 114 patients with MS upon diagnosis. By stratifying patients according to their genetic background, statistical correlations with clinical parameters were performed. Notably, in Met-carrier patients, we observed a decoupling of miR-142-3p levels from IL1ß levels in the CSF, as well as from of disease severity (Expanded Disability Status Score, EDSS; Multiple Sclerosis Severity Score, MSSS; Age-Related Multiple Sclerosis Severity Score, ARMSS) and progression (Progression Index, PI). Our discovery of the interference between BDNF Val66Met polymorphism and the synaptotoxic IL1ß-miR-142-3p axis, therefore hampering miR-142-3p action on MS course, provides valuable insights for further development of personalized medicine in the field.

Low-contrast visual acuity test is associated with central inflammation and predicts disability development in newly diagnosed multiple sclerosis patients.

Introduction: The visual system is a prominent site of damage in MS since the earliest phases of the disease. Altered low-contrast visual acuity (LCVA) test has been associated with visual impairment and retinal degeneration, predicting medium- and long-term disability. However, it is unclear whether LCVA may also represent a reliable measure of neuroinflammation and a predictor of disease evolution in the very early stages of MS. Methods: We explored in a group of 76 consecutive newly diagnosed relapsing-remitting MS (RR-MS) patients without visual impairment or altered visual evoked potentials, the association between LCVA scores at 2.5% and 1.25% and clinical characteristics, including prospective disability evaluated after 1- and 2 years of follow-up. Associations between LCVA and the CSF levels of IL-10 at diagnosis were also analyzed. Results: A negative correlation was found between LCVA at 2.5% and Expanded Disability Status Scale (EDSS) evaluated at first (Spearman's Rho = -0.349, p = 0.005, n = 62) and second year (Spearman's Rho = -0.418, p < 0.001, n = 62) of follow-up, and negative correlations were found with Multiple Sclerosis Severity Score (MSSS) at first (Spearman's Rho = -0.359, p = 0.004, n = 62) and second year (Spearman's Rho = -0.472, p < 0.001, n = 62). All the data were confirmed by a mixed effect model, considering other clinical variables. A positive correlation was found between the CSF concentrations of IL-10 and LCVA at 2.5% (Spearman's Rho = 0.272, p = 0.020, n = 76), and 1.25% (Spearman's Rho, = 0.276, p = 0.018, n = 76), also evidenced in a linear regression. Discussion: In MS patients at diagnosis, altered LCVA may be associated with CSF inflammation and represent a useful parameter to identify patients with worse disease course.

Mood disturbances in newly diagnosed Parkinson's Disease patients reflect intrathecal inflammation.

In Parkinson's disease (PD), neuroinflammation may be involved in the pathogenesis of mood disorders, contributing to the clinical heterogeneity of the disease. The cerebrospinal fluid (CSF) levels of interleukin (IL)-1ß, IL-2, IL-6, IL-7, IL-8, IL-9, IL-12, IL-17, interferon (IFN)γ, macrophage inflammatory protein 1-alpha (MIP-1a), MIP-1b, granulocyte colony stimulating factor (GCSF), eotaxin, tumor necrosis factor (TNF), and monocyte chemoattractant protein 1 (MCP-1), were assessed in 45 newly diagnosed and untreated PD patients and in 44 control patients. Spearman's correlations were used to explore possible associations between CSF cytokines and clinical variables including mood. Benjamini-Hochberg (B-H) correction for multiple comparisons was applied. Linear regression was used to test significant associations correcting for other clinical variables. In PD patients, higher CSF concentrations of the inflammatory molecules IL-6, IL-9, IFNγ, and GCSF were found (all B-H corrected p < 0.02). Significant associations were found between BDI-II and the levels of IL-6 (Beta = 0.438; 95%CI 1.313-5.889; p = 0.003) and IL-8 (Beta = 0.471; 95%CI 0.185-0.743; p = 0.002). Positive associations were also observed between STAI-Y state and both IL-6 (Beta = 0.452; 95%CI 1.649-7.366; p = 0.003), and IL-12 (Beta = 0.417; 95%CI 2.238-13.379; p = 0.007), and between STAI-Y trait and IL-2 (Beta = 0.354; 95%CI 1.923-14.796; p = 0.012), IL-6 (Beta = 0.362; 95%CI 0.990-6.734; p = 0.01), IL-8 (Beta = 0.341; 95%CI 0.076-0.796; p = 0.019), IL-12 (Beta = 0.328; 95%CI 0.975-12.135; p = 0.023), and IL-17 (Beta = 0.334; 95CI 0.315-4.455; p = 0.025). An inflammatory CSF milieu may be associated with depression and anxiety in the early phases of PD, supporting a role of neuroinflammation in the pathogenesis of mood disturbances.

Preventive exercise and physical rehabilitation promote long-term potentiation-like plasticity expression in patients with multiple sclerosis.

BACKGROUND AND PURPOSE: Loss of long-term potentiation (LTP) expression has been associated with a worse disease course in relapsing-remitting multiple sclerosis (RR-MS) and represents a pathophysiological hallmark of progressive multiple sclerosis (PMS). Exercise and physical rehabilitation are the most prominent therapeutic approaches to promote synaptic plasticity. We aimed to explore whether physical exercise is able to improve the expression of LTP-like plasticity in patients with multiple sclerosis (MS). METHODS: In 46 newly diagnosed RR-MS patients, we explored the impact of preventive exercise on LTP-like plasticity as assessed by intermittent theta-burst stimulation. Patients were divided into sedentary or active, based on physical activity performed during the 6 months prior to diagnosis. Furthermore, in 18 patients with PMS, we evaluated the impact of an 8-week inpatient neurorehabilitation program on clinical scores and LTP-like plasticity explored using paired associative stimulation (PAS). Synaptic plasticity expression was compared in patients and healthy subjects. RESULTS: Reduced LTP expression was found in RR-MS patients compared with controls. Exercising RR-MS patients showed a greater amount of LTP expression compared with sedentary patients. In PMS patients, LTP expression was reduced compared with controls and increased after 8 weeks of rehabilitation. In this group of patients, LTP magnitude at baseline predicted the improvement in hand dexterity. CONCLUSIONS: Both preventive exercise and physical rehabilitation may enhance the expression of LTP-like synaptic plasticity in MS, with potential beneficial effects on disability accumulation.

SARS-CoV-2 vaccination and multiple sclerosis: a large multicentric study on relapse risk after the third booster dose.

BACKGROUND: COVID-19 vaccines have been recommended to people with multiple sclerosis (pwMS) and, to ensure durable immunity, a third booster dose has been administered in several countries. Data about potential risks associated with the third booster dose in pwMS, such as vaccine-triggered disease exacerbations, are still scarce. OBJECTIVE: To investigate whether the administration of a third booster dose of mRNA COVID-19 vaccines was associated with an increased risk of short-term disease reactivation in a large cohort of pwMS. METHODS: We retrospectively selected 1265 pwMS who received a third booster dose of an mRNA COVID-19 vaccine. Demographic and clinical data were collected, including the presence, number and characteristics of relapses in the 60 days prior to and after the third booster dose. RESULTS: In the selected cohort, the relapse rate in the two months after administration of the third booster dose of mRNA COVID-19 vaccines did not increase when compared with the prior two months. Indeed, the percentage of pwMS experiencing relapses in the 60 days following the administration of the third booster dose was 2.1%, similar to the percentage recorded in 60 days prior to vaccination, which was 1.9%. CONCLUSIONS: The third booster dose of mRNA COVID-19 vaccines appeared to be safe for pwMS.

Physical exercise and synaptic protection in human and pre-clinical models of multiple sclerosis.

In multiple sclerosis, only immunomodulatory and immunosuppressive drugs are recognized as disease-modifying therapies. However, in recent years, several data from pre-clinical and clinical studies suggested a possible role of physical exercise as disease-modifying therapy in multiple sclerosis. Current evidence is sparse and often conflicting, and the mechanisms underlying the neuroprotective and antinflammatory role of exercise in multiple sclerosis have not been fully elucidated. Data, mainly derived from pre-clinical studies, suggest that exercise could enhance long-term potentiation and thus neuroplasticity, could reduce neuroinflammation and synaptopathy, and dampen astrogliosis and microgliosis. In humans, most trials focused on direct clinical and MRI outcomes, as investigating synaptic, neuroinflammatory, and pathological changes is not straightforward compared to animal models. The present review analyzed current evidence and limitations in research concerning the potential disease-modifying therapy effects of exercise in multiple sclerosis in animal models and human studies.

Topographical Correlation between Structural and Functional Impairment of the Macular Inner Retinal Layers in Multiple Sclerosis Eyes with a History of Optic Neuropathy.

We investigated the potential correlation between morphological and functional parameters describing the rarefaction and dysfunction of retinal ganglion cells (RGCs), located in the macula, in multiple sclerosis eyes with a history of optic neuritis (MS-ON). A total of 19 MS-ON eyes from 19 MS patients (mean age: 44.16 ± 4.66 years; 11 females and 8 males), with a mean disease duration of 10.06 ± 6.12 years and full recovery of visual acuity, and 30 age-similar (mean age: 45.09 ± 5.08 years) healthy eyes were submitted for ophthalmological evaluation using swept-source optical coherence tomography (SS-OCT) and multifocal photopic negative response (mfPhNR) to study the structural and functional features of localized RGCs. Both GCL+ thickness (via SS-OCT) and response amplitude density (RAD) (via mfPhNR) measurements were obtained from annular regions and ETDRS sectors. Morphological and electrophysiological data from the control and MS groups were compared by using an ANOVA test. GCL+ values were correlated with the corresponding RADs derived from almost superimposable areas using Pearson's tests (p < 0.01). In MS-ON eyes, the mean values of macular GCL+-T and mfPhNR RAD detected in all rings and ETDRS sectors were significantly reduced (p < 0.01) when compared with control ones. In addition, when plotting the GCL+-T and mfPhNR RAD individual data from MS-ON eyes, we found statistically significant linear correlations (p < 0.01) when considering responses from both rings and sectors. In conclusion, in MS-ON eyes, a topographical correlation between structural and functional impairment of macular RGCs occurs.

Distinct intrathecal inflammatory signatures following relapse and anti-COVID-19 mRNA vaccination in multiple sclerosis.

BACKGROUND: The role of vaccine-mediated inflammation in exacerbating multiple sclerosis (MS) is a matter of debate. OBJECTIVE: In this cross-sectional study, we compared the cerebrospinal fluid (CSF) inflammation associated with MS relapses or anti-COVID-19 mRNA vaccinations in relapsing-remitting multiple sclerosis (RRMS). METHODS: We dosed CSF cytokines in 97 unvaccinated RRMS patients with clinical relapse within the last 100 days. In addition, we enrolled 29 stable RRMS and 24 control patients receiving COVID-19 vaccine within the last 100 days. RESULTS: In RRMS patients, a negative association was found between relapse distance and the CSF concentrations of the pro-inflammatory cytokines interleukin (IL)-2 (beta = -0.265, p = 0.016), IL-6 (beta = -0.284, p = 0.01), and IL-17 (beta = -0.224, p = 0.044). Conversely, vaccine distance positively correlated with a different set of cytokines including IL-12 (beta = 0.576, p = 0.002), IL-13 (beta = 0.432, p = 0.027), and IL-1ra (beta = 0.387, p = 0.05). These associations were significant also considering other clinical characteristics. No significant associations emerged between vaccine distance and CSF molecules in the control group. CONCLUSION: Vaccine for COVID-19 induces a central inflammatory response in RRMS patients that is qualitatively different from that associated with disease relapse.

Homeostasis of serine enantiomers is disrupted in the post-mortem caudate putamen and cerebrospinal fluid of living Parkinson's disease patients.

L-serine generated in astrocytes plays a pivotal role in modulating essential neurometabolic processes, while its enantiomer, D-serine, specifically regulates NMDA receptor (NMDAR) signalling. Despite their physiological relevance in modulating cerebral activity, serine enantiomers metabolism in Parkinson's disease (PD) remains elusive. Using High-Performance Liquid Chromatography (HPLC), we measured D- and L-serine levels along with other amino acids known to modulate NMDAR function, such as L-glutamate, L-aspartate, D-aspartate, and glycine, in the post-mortem caudate putamen (CPu) and superior frontal gyrus (SFG) of PD patients. Moreover, we examined these amino acids in the cerebrospinal fluid (CSF) of de novo living PD, Alzheimer's disease (AD), and amyotrophic lateral sclerosis (ALS) patients versus subjects with other neurological disorders (OND), used as control. We found higher D-serine and L-serine levels in the CPu of PD patients but not in the SFG, a cerebral region that, in contrast to the CPu, is not innervated by nigral dopaminergic terminals. We also highlighted a significant elevation of both serine enantiomers in the CSF samples from PD but not in those of AD and ALS patients, compared with control subjects. By contrast, none or only minor changes were found in the amount of other NMDAR modulating amino acids. Our findings identify D-serine and L-serine level upregulation as a biochemical signature associated with nigrostriatal dopaminergic degeneration in PD.

Cerebrospinal fluid, brain, and spinal cord levels of L-aspartate signal excitatory neurotransmission abnormalities in multiple sclerosis patients and experimental autoimmune encephalomyelitis mouse model.

The neuroinflammatory process characterizing multiple sclerosis (MS) is associated with changes in excitatory synaptic transmission and altered central concentrations of the primary excitatory amino acid, L-glutamate (L-Glu). Recent findings report that cerebrospinal fluid (CSF) levels of L-Glu positively correlate with pro-inflammatory cytokines in MS patients. However, to date, there is no evidence about the relationship between the other primary excitatory amino acid, L-aspartate (L-Asp), its derivative D-enantiomer, D-aspartate, and the levels of pro-inflammatory and anti-inflammatory cytokines in the CSF of MS. In the present study, we measured by HPLC the levels of these amino acids in the cortex, hippocampus, cerebellum, and spinal cord of mice affected by experimental autoimmune encephalomyelitis (EAE). Interestingly, in support of glutamatergic neurotransmission abnormalities in neuroinflammatory conditions, we showed reduced L-Asp levels in the cortex and spinal cord of EAE mice and increased D-aspartate/total aspartate ratio within the cerebellum and spinal cord of these animals. Additionally, we found significantly decreased CSF levels of L-Asp in both relapsing-remitting (n = 157) MS (RR-MS) and secondary progressive/primary progressive (n = 22) (SP/PP-MS) patients, compared to control subjects with other neurological diseases (n = 40). Importantly, in RR-MS patients, L-Asp levels were correlated with the CSF concentrations of the inflammatory biomarkers G-CSF, IL-1ra, MIP-1ß, and Eotaxin, indicating that the central content of this excitatory amino acid, as previously reported for L-Glu, reflects a neuroinflammatory environment in MS. In keeping with this, we revealed that CSF L-Asp levels were positively correlated with those of L-Glu, highlighting the convergent variation of these two excitatory amino acids under inflammatory synaptopathy occurring in MS.

MiR-142-3p is a Critical Modulator of TNF-mediated Neuronal Toxicity in Multiple Sclerosis.

BACKGROUND: TNF-dependent synaptotoxicity contributes to the neuronal damage occurring in patients with Multiple Sclerosis (pwMS) and its mouse model Experimental Autoimmune Encephalomyelitis (EAE). Here, we investigated miR-142-3p, a synaptotoxic microRNA induced by inflammation in EAE and MS, as a potential downstream effector of TNF signalling. METHODS: Electrophysiological recordings, supported by molecular, biochemical and histochemical analyses, were performed to explore TNF-synaptotoxicity in the striatum of EAE and healthy mice. MiR-142 heterozygous (miR-142 HE) mice and/or LNA-anti miR-142-3p strategy were used to verify the TNF-miR-142-3p axis hypothesis. The cerebrospinal fluid (CSF) of 151 pwMS was analysed to evaluate possible correlation between TNF and miR-142-3p levels and their impact on clinical parameters (e.g. progression index (PI), age-related clinical severity (gARMSS)) and MRI measurements at diagnosis (T0). RESULTS: High levels of TNF and miR-142-3p were detected in both EAE striatum and MS-CSF. The TNF-dependent glutamatergic alterations were prevented in the inflamed striatum of EAE miR-142 HE mice. Accordingly, TNF was ineffective in healthy striatal slices incubated with LNA-anti miR- 142-3p. However, both preclinical and clinical data did not validate the TNF-miR-142-3p axis hypothesis, suggesting a permissive neuronal role of miR-142-3p on TNF-signalling. Clinical data showed a negative impact of each molecule on disease course and/or brain lesions and unveiled that their high levels exert a detrimental synergistic effect on disease activity, PI and white matter lesion volume. CONCLUSION: We propose miR-142-3p as a critical modulator of TNF-mediated neuronal toxicity and suggest a detrimental synergistic action of these molecules on MS pathology.

Genetic regulation of IL-8 influences disease presentation of multiple sclerosis.

BACKGROUND: Individual genetic variability may influence the course of multiple sclerosis (MS). The interleukin (IL)-8C>T rs2227306 single nucleotide polymorphism (SNP) regulates IL-8 activity in other clinical conditions; however, its role in MS has never been investigated. OBJECTIVES: To explore the association between IL-8 SNP rs2227306, cerebrospinal fluid (CSF) IL-8 concentrations, clinical, and radiological characteristics in a group of newly diagnosed MS patients. METHODS: In 141 relapsing-remitting (RR)-MS patients, rs2227306 polymorphism, CSF levels of IL-8, clinical, and demographical characteristics were determined. In 50 patients, structural magnetic resonance imaging (MRI) measures were also assessed. RESULTS: An association between CSF IL-8 and Expanded Disability Status Scale (EDSS) at diagnosis was found in our set of patients (r = 0.207, p = 0.014). CSF IL-8 concentrations were significantly higher in patients carrying the T variant of rs2227306 (p = 0.004). In the same group, a positive correlation emerged between IL-8 and EDSS (r = 0.273, p = 0.019). Finally, a negative correlation between CSF levels of IL-8 and cortical thickness emerged in rs2227306T carriers (r = -0.498, p = 0.005). CONCLUSION: We describe for the first time a role of SNP rs2227306 of IL-8 gene in regulating the expression and the activity of this inflammatory cytokine in MS.

Osteopontin Is Associated with Multiple Sclerosis Relapses.

BACKGROUND: Osteopontin, an extracellular matrix protein involved in bone remodeling, tissue repair and inflammation, has previously been associated with increased inflammation and neurodegeneration in multiple sclerosis (MS), promoting a worse disease course. Osteopontin is also likely involved in acute MS relapses. METHODS: In 47 patients with relapsing-remitting MS, we explored the correlation between the time elapsed between the last clinical relapse and lumbar puncture, and the cerebrospinal fluid (CSF) levels of osteopontin and a group of inflammatory cytokines and adipokines such as resistin, plasminogen activator inhibitor-1, osteoprotegerin, interleukin (IL)-1ß, IL-2, IL-6 and IL-1 receptor antagonist (IL-1ra). We also analyzed the correlations between CSF levels of osteopontin and the other CSF molecules considered. RESULTS: Osteopontin CSF concentrations were higher in patients with a shorter time interval between the last clinical relapse and CSF withdrawal. In addition, CSF levels of osteopontin were positively correlated with the proinflammatory cytokines IL-2 and IL-6 and negatively correlated with the anti-inflammatory molecule IL-1ra. CONCLUSIONS: Our results further suggest the role of osteopontin in acute MS relapses showing that, in proximity to relapses, osteopontin expression in CSF may be increased along with other proinflammatory mediators and correlated with decreased concentrations of anti-inflammatory molecules.

BACE1 influences clinical manifestations and central inflammation in relapsing remitting multiple sclerosis.

Neurodegenerative and inflammatory processes influence the clinical course of multiple sclerosis (MS). The ß-site amyloid precursor protein cleaving enzyme 1 (BACE1) has been associated with cognitive dysfunction, amyloid deposition and neuroinflammation in Alzheimer's disease. We explored in a group of 50 patients with relapsing-remitting MS the association between the cerebrospinal fluid (CSF) levels of BACE1, clinical characteristics at the time of diagnosis and prospective disability after three-years follow-up. In addition, we assessed the correlations between the CSF levels of BACE 1, amyloid ß (Aß) 1-40 and 1-42, phosphorylated tau (pTau), lactate, and a set of inflammatory and anti-inflammatory molecules. BACE1 CSF levels were correlated positively with depression as measured with Beck Depression Inventory-Second Edition scale, and negatively with visuospatial memory performance evaluated by the Brief Visuospatial Memory Test-Revised. In addition, BACE CSF levels were positively correlated with Bayesian Risk Estimate for MS at onset, and with Expanded Disability Status Scale score assessed three years after diagnosis. Furthermore, a positive correlation was found between BACE1, amyloid ß 42/40 ratio (Spearman's r = 0.334, p = 0.018, n = 50), pTau (Spearman's r = 0.304, p = 0.032, n = 50) and lactate concentrations (Spearman's r = 0.361, p = 0.01, n = 50). Finally, an association emerged between BACE1 CSF levels and a group of pro and anti-inflammatory molecules, including interleukin (IL)-4, IL-17, IL-13, IL-9 and interferon-γ. BACE1 may have a role in different key mechanisms such as neurodegeneration, oxidative stress and inflammation, influencing mood, cognitive disorders and disability progression in MS.