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Esclerosi múltiple; Cadena lleugera de neurofilaments sèrics Esclerosis múltiple; Cadena ligera de neurofilamentos séricos Multiple sclerosis; Serum neurofilament light chain Objective Evaluation of serum neurofilament light chain (sNfL), measured using high-throughput assays on widely accessible platforms in large, real-world MS populations, is a critical step for sNfL to be utilized in clinical practice. Methods Multiple Sclerosis Partners Advancing Technology and Health Solutions (MS PATHS) is a network of healthcare institutions in the United States and Europe collecting standardized clinical/imaging data and biospecimens during routine clinic visits. sNfL was measured in 6974 MS and 201 healthy control (HC) participants, using a high-throughput, scalable immunoassay. Results Elevated sNfL levels for age (sNfL-E) were found in 1238 MS participants (17.8%). Factors associated with sNfL-E included male sex, younger age, progressive disease subtype, diabetes mellitus, impaired renal function, and active smoking. Higher body mass index (BMI) was associated with lower odds of elevated sNfL. Active treatment with disease-modifying therapy was associated with lower odds of sNfL-E. MS participants with sNfL-E exhibited worse neurological function (patient-reported disability, walking speed, manual dexterity, and cognitive processing speed), lower brain parenchymal fraction, and higher T2 lesion volume. Longitudinal analyses revealed accelerated short-term rates of whole brain atrophy in sNfL-E participants and higher odds of new T2 lesion development, although both MS participants with or without sNfL-E exhibited faster rates of whole brain atrophy compared to HC. Findings were consistent in analyses examining age-normative sNfL Z-scores as a continuous variable. Interpretation Elevated sNfL is associated with clinical disability, inflammatory disease activity, and whole brain atrophy in MS, but interpretation needs to account for comorbidities including impaired renal function, diabetes, and smoking. Study funding was provided from the National Institutes of Health (K23NS117883 to E.S.S.; K01MH121582 to K.C.F.; U01NS111678 to P.A.C.), National Multiple Sclerosis Society (RG-1904-33834 to E.S.S.; RG-1904-33800 to P.A.C.), and Biogen.

Background: Serum levels of neurofilament light chain (sNfL) are a potentially useful biomarker for assessing the efficacy of multiple sclerosis (MS) treatments. Objective: To compare levels of sNfL in patients with MS who switched from natalizumab every 4 weeks (Q4W) to extended interval dosing (EID) and patients who remained on Q4W dosing in real-world clinical practice. Methods: This was a retrospective analysis of samples from patients treated with natalizumab from 2010 to 2015 at a single center in the United States. Levels of sNfL were compared in patients who stayed on Q4W dosing or who switched to EID (parallel-arm analyses) and during Q4W and EID periods in patients who switched to EID (pre- and post-switch analyses). Results: The analysis included 139 patients (Q4W: n = 79; EID: n = 60). After adjustment, levels of sNfL did not significantly differ between patients who remained on Q4W dosing and those who switched to EID in parallel-arm analyses (adjusted Q4W-EID difference = 0.51 pg/mL; p = 0.60) or pre- and post-switch analyses (adjusted difference = 0.96 pg/mL; p = 0.10). Conclusion: These sNfL biomarker results suggest that the effectiveness of natalizumab is maintained in patients who switch from Q4W dosing to EID.

Background CombiRx was a randomized, double-blind, placebo-controlled phase 3 trial in treatment-naive relapsing-remitting multiple sclerosis (RRMS) patients randomized to intramuscular interferon beta-1a (IM IFN beta-1a), glatiramer acetate (GA), or both therapies. Objective This analysis investigated changes in serum neurofilament light-chain (sNfL) levels in response to treatment and assessed baseline sNfL as a predictor of relapse. Methods RRMS patients treated with IM IFN beta-1a 30 µg weekly + placebo (n = 159), GA 20 mg/mL daily + placebo (n = 172), or IM IFN beta-1a + GA (n = 344) were included. A linear mixed model compared sNfL values over time. Cox regression models analyzed baseline sNfL and gadolinium-enhancing (Gd+) lesions as predictors of relapse. Results In all treatment arms, the proportion of patients with sNfL ≥16 pg/mL decreased significantly from baseline to 6 months and was maintained at 36 months. A significantly higher percentage of patients with both baseline sNfL ≥16 pg/mL and ≥1 Gd+ lesion experienced relapses within 90 days compared to patients with sNfL Conclusion sNfL levels were reduced within 6 months and remained low at 36 months. Results suggest that the combination of lesion activity and sNfL was a stronger predictor of relapse than either factor alone.

BackgroundNeurofilament light chain (NfL) is an axonal cytoskeletal protein that is released into the extracellular space following neuronal or axonal injury associated with neurological conditions such as multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS), and other diseases. NfL is detectable in cerebrospinal fluid (CSF) and blood. Numerous studies in MS have demonstrated that NfL correlates with disease activity, predicts disease progression, and is reduced by treatment with MS disease-modifying drugs, making NfL an attractive candidate to supplement existing clinical and imaging measures in MS. However, for NfL to achieve its potential as a clinically useful biomarker for clinical decision-making or drug development, a standardized, practical, widely accessible assay is needed. Our objective was to validate the analytical performance of the novel serum neurofilament light (sNfl) assay on the ADVIA Centaur® XP immunoassay system.MethodsThe research assay was evaluated on the ADVIA Centaur XP immunoassay system from Siemens Healthineers. The lower limit of quantitation (LLoQ), intra-assay variation, assay range, cross-reactivity with neurofilament medium and heavy chains, and effect of interfering substances were determined. NfL assay values in serum and CSF were compared with radiological and clinical disease activity measures in patients with MS and ALS, respectively. This assay was further optimized to utilize serum, plasma, and CSF sample types and transferred to Siemens’ CLIA laboratory, where it was analytically validated as a laboratory-developed test.ResultsIn this study, a LLoQ of 1.85 pg/mL, intra-assay variation of ConclusionThe analytical performance of the NfL assay fulfilled all acceptance criteria; therefore, we believe the assay is acceptable for use in both research and clinical practice settings to determine elevated sNfL levels in patients.

Multiple sclerosis; SARS-COV-2 vaccination; Humoral immune response Esclerosis múltiple; Vacunación SARS-COV-2; Respuesta inmune humoral Esclerosi múltiple; Vacunació SARS-COV-2; Resposta immune humoral Background: The impact of multiple sclerosis (MS) disease-modifying therapies (DMTs) on SARS-CoV-2 vaccination response is uncertain. Methods: Post-SARS-CoV-2 vaccination blood samples across multiple DMTs were tested for SARS-CoV-2 immunoglobulin G (IgG) response. Results: Three hundred twenty-two people with MS were included; 91.9% received an mRNA vaccine. Post-vaccination reactive IgG rates (IgG index > 1) were 40% for anti-CD20 (32/80 patients); 41% for sphingosine 1-phosphate receptor modulators (S1PRM, 16/39); and 100% for all other classes, including the no DMT group. Conclusion: Anti-CD20 therapies and S1PRMs reduce IgG response to SARS-CoV-2 vaccination; IgG response is preserved with other DMTs. The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This study was sponsored by Biogen (Cambridge, MA, USA). Funding for writing and editorial support was provided by Biogen.

With the availability of complete genome sequence for Drosophila melanogaster, one of the next strategic goals for fly researchers is a complete gene knockout collection. The P-element transposon, the workhorse of D. melanogaster molecular genetics, has a pronounced nonrandom insertion spectrum. It has been estimated that 87% saturation of the approximately 13,500-gene complement of D. melanogaster might require generating and analyzing up to 150,000 insertions. We describe specific improvements to the lepidopteran transposon piggyBac and the P element that enabled us to tag and disrupt genes in D. melanogaster more efficiently. We generated over 29,000 inserts resulting in 53% gene saturation and a more diverse collection of phenotypically stronger insertional alleles. We found that piggyBac has distinct global and local gene-tagging behavior from that of P elements. Notably, piggyBac excisions from the germ line are nearly always precise, piggyBac does not share chromosomal hotspots associated with P and piggyBac is more effective at gene disruption because it lacks the P bias for insertion in 5' regulatory sequences.

Background: In most organisms in which acute ethanol exposure has been studied, it leads to similar changes in behavior. Generally, low ethanol doses activate the central nervous system, whereas high doses are sedative. Sensitivity to the acute intoxicating effects of ethanol is in part under genetic control in rodents and humans, and reduced sensitivity in humans predicts the development of alcoholism (Crabbe et al., 1994; Schuckit, 1994). We have established Drosophila melanogaster as a model organism to study the mechanisms that regulate acute sensitivity to ethanol. Methods: We measured the effects of ethanol vapor on Drosophila locomotor behaviors by using three different assays. Horizontal locomotion was quantified in a locomotor chamber, turning behavior was assayed in narrow tubes, and ethanol-induced loss of postural control was measured in an inebriometer. Mutants with altered sensitivity to the acute effects of ethanol were generated by treatment with ethyl methane sulfonate and isolated by selection in the inebriometer. We ascertained the effects of these mutations on ethanol pharmacokinetics by measuring ethanol levels in extracts of flies at various times during and after ethanol exposure. Results: Among nearly 30,000 potentially mutant flies tested, we isolated 19 mutant strains with reduced and 4 strains with increased sensitivity to the acute effects of ethanol as measured in the inebriometer. Of these mutants, four showed changes in ethanol absorption. Two mutants, named barfly and tipsy to reflect their reduced and increased ethanol sensitivity in the inebriometer, respectively, were analyzed for locomotor behaviors. Both mutants exhibited ethanol-induced hyperactivity that was indistinguishable from wild type. However, barfly and tipsy displayed reduced and increased sensitivity to the sedative effects of ethanol, respectively. Finally, both mutants showed an increased rate of ethanol-induced turning behavior. Conclusions: The effects of acute ethanol exposure on Drosophila locomotor behaviors are remarkably similar to those described for mammals. The analysis of mutants with altered sensitivity to ethanol revealed that the genetic pathways which regulate these responses are complex and that single genes can affect hyperactivity, turning, and sedation independently.

DIFFERENTIATION of the Drosophila retina is asynchronous: it starts at the posterior margin of the eye imaginal disc and progresses anteriorly over two days. During this time the disc continues to grow, increasing in size by approximately eightfold. An indentation in the epithelium, the morphogenetic furrow1, marks the front edge of the differentiation wave. Anterior progression of the furrow is thought to be driven by signals emanating from differentiating photoreceptor cells in the posterior eye disc2,3. A good candidate for such a signal is the product of the hedgehog (hh) gene4–7; it is expressed, and presumably secreted, by differentiating photoreceptors and its function is required for continued furrow movement2,3. Here we show that ectopic expression of hedgehog sets in motion ectopic furrows in the anterior eye disc. In addition to changes in cell shape, these ectopic furrows are associated with a tightly orchestrated series of events, including proliferation, cell cycle synchronization and pattern formation, that parallel normal furrow progression. We propose that the morphogenetic furrow coincides with a transient boundary that coordinates growth and differentiation of the eye disc, and that hedgehog is necessary and sufficient to propagate this boundary across the epithelium.

Upon exposure to ethanol, Drosophila display behaviors that are similar to ethanol intoxication in rodents and humans. Using an inebriometer to measure ethanol-induced loss of postural control, we identified cheapdate, a mutant with enhanced sensitivity to ethanol. Genetic and molecular analyses revealed that cheapdate is an allele of the memory mutant amnesiac. amnesiac has been postulated to encode a neuropeptide that activates the cAMP pathway. Consistent with this, we find that enhanced ethanol sensitivity of cheapdate can be reversed by treatment with agents that increase cAMP levels or PKA activity. Conversely, genetic or pharmacological reduction in PKA activity results in increased sensitivity to ethanol. Taken together, our results provide functional evidence for the involvement of the cAMP signal transduction pathway in the behavioral response to intoxicating levels of ethanol.

Summary Huntington's disease (HD) is a neurodegenerative disorder caused by a polyglutamine expansion within Huntingtin (Htt) protein. In the phenotypic screen we identified a class of quinazoline-derived compounds that delayed a progression of a motor phenotype in transgenic Drosophila HD flies. We found that the store-operated calcium (Ca 2+ ) entry (SOC) pathway activity is enhanced in neuronal cells expressing mutant Htt and that the identified compounds inhibit SOC pathway in HD neurons. The same compounds exerted neuroprotective effects in glutamate-toxicity assays with YAC128 medium spiny neurons primary cultures. We demonstrated a key role of TRPC1 channels in supporting SOC pathway in HD neurons. We concluded that the TRPC1-mediated neuronal SOC pathway constitutes a novel target for HD treatment and that the identified compounds represent a novel class of therapeutic agents for treatment of HD and possibly other neurodegenerative disorders.

Background: Drugs of abuse have a common property in mammals, which is their ability to facilitate the release of the neurotransmitter and neuromodulator dopamine in specific brain regions involved in reward and motivation. This increase in synaptic dopamine levels is believed to act as a positive reinforcer and to mediate some of the acute responses to drugs. The mechanisms by which dopamine regulates acute drug responses and addiction remain unknown. Results: We present evidence that dopamine plays a role in the responses of Drosophila to cocaine, nicotine or ethanol. We used a startle-induced negative geotaxis assay and a locomotor tracking system to measure the effect of psychostimulants on fly behavior. Using these assays, we show that acute responses to cocaine and nicotine are blunted by pharmacologically induced reductions in dopamine levels. Cocaine and nicotine showed a high degree of synergy in their effects, which is consistent with an action through convergent pathways. In addition, we found that dopamine is involved in the acute locomotor-activating effect, but not the sedating effect, of ethanol. Conclusions: We show that in Drosophila , as in mammals, dopaminergic pathways play a role in modulating specific behavioral responses to cocaine, nicotine or ethanol. We therefore suggest that Drosophila can be used as a genetically tractable model system in which to study the mechanisms underlying behavioral responses to multiple drugs of abuse.