Estradiol reverses excitatory synapse loss in a cellular model of neuropsychiatric disorders

Loss of glutamatergic synapses is thought to be a key cellular pathology associated with neuropsychiatric disorders including schizophrenia (SCZ) and major depressive disorder (MDD). Genetic and cellular studies of SCZ and MDD using in vivo and in vitro systems have supported a key role for dysfunction of excitatory synapses in the pathophysiology of these disorders. Recent clinical studies have demonstrated that the estrogen, 17β-estradiol can ameliorate many of the symptoms experienced by patients. Yet, to date, our understanding of how 17β-estradiol exerted these beneficial effects is limited. In this study, we have tested the hypothesis that 17β-estradiol can restore dendritic spine number in a cellular model that recapitulates the loss of synapses associated with SCZ and MDD. Ectopic expression of wildtype, mutant or shRNA-mediated knockdown of Disrupted in Schizophrenia 1 (DISC1) reduced dendritic spine density in primary cortical neurons. Acute or chronic treatment with 17β-estradiol increased spine density to control levels in neurons with altered DISC1 levels. In addition, 17β-estradiol reduced the extent to which ectopic wildtype and mutant DISC1 aggregated. Furthermore, 17β-estradiol also caused the enrichment of synaptic proteins at synapses and increased the number of dendritic spines containing PSD-95 or that overlapped with the pre-synaptic marker bassoon. Taken together, our data indicates that estrogens can restore lost excitatory synapses caused by altered DISC1 expression, potentially through the trafficking of DISC1 and its interacting partners. These data highlight the possibility that estrogens exert their beneficial effects in SCZ and MDD in part by modulating dendritic spine number

Perspectives and experiences with COVID-19 vaccines in people with MS

Background: People with MS may have unique perspectives on COVID-19 vaccines due to their condition and/or medications. Objective: Assess perspectives and experiences with COVID-19 vaccination, and quantify variables impacting COVID-19 vaccine willingness in people with MS. Methods: A survey captured demographics, MS characteristics, and COVID-19 infection and exposures data; opinions on COVID-19 vaccine safety, side effects, and efficacy; and experiences following vaccination. Chi-square tests and a logistic regression model were used to denote between-group differences and variables predicting vaccine willingness, respectively. Results: Most (87.8%) of the 237 participants were willing to receive the vaccine. Fifteen percent held or delayed a DMT dose for vaccination. MS symptoms worsened in a minority (7.6% first/only dose; 14.7% second dose), and most side effects were mild (80.0%; 55.3%). Those not planning to receive the vaccine were primarily concerned with long-term safety (70.4%). Medical comorbidities (adjusted odds ratio [aOR]=5.222; p=0.04) and following infection prevention precautions (aOR=6.330; p=0.008) were associated with vaccine willingness. Conclusion: Most individuals with MS surveyed plan to receive the COVID-19 vaccine. People with MS experience similar side effects to the general population, and few experience transient MS symptom worsening. These results can inform conversations on vaccination between providers and people with MS

Developmental seizures and mortality result from reducing GABAᴀ receptor α2-subunit interaction with collybistin

Fast inhibitory synaptic transmission is mediated by γ-aminobutyric acid type A receptors (GABAARs) that are enriched at functionally diverse synapses via mechanisms that remain unclear. Using isothermal titration calorimetry and complementary methods we demonstrate an exclusive low micromolar binding of collybistin to the α2-subunit of GABAARs. To explore the biological relevance of collybistin-α2-subunit selectivity, we generate mice with a mutation in the α2-subunit-collybistin binding region (Gabra2-1). The mutation results in loss of a distinct subset of inhibitory synapses and decreased amplitude of inhibitory synaptic currents. Gabra2–1 mice have a striking phenotype characterized by increased susceptibility to seizures and early mortality. Surviving Gabra2-1 mice show anxiety and elevations in electroencephalogram δ power, which are ameliorated by treatment with the α2/α3-selective positive modulator, AZD7325. Taken together, our results demonstrate an α2-subunit selective binding of collybistin, which plays a key role in patterned brain activity, particularly during development

Molecular architecture of potassium chloride co-transporter KCC2

KCC2 is a neuron specific K+-Cl− co-transporter that controls neuronal chloride homeostasis, and is critically involved in many neurological diseases including brain trauma, epilepsies, autism and schizophrenia. Despite significant accumulating data on the biology and electrophysiological properties of KCC2, structure-function relationships remain poorly understood. Here we used calixarene detergent to solubilize and purify wild-type non-aggregated and homogenous KCC2. Specific binding of inhibitor compound VU0463271 was demonstrated using surface plasmon resonance (SPR). Mass spectrometry revealed glycosylations and phosphorylations as expected from functional KCC2. We show by electron microscopy (EM) that KCC2 exists as monomers and dimers in solution. Monomers are organized into “head” and “core” domains connected by a flexible “linker”. Dimers are asymmetrical and display a bent “S-shape” architecture made of four distinct domains and a flexible dimerization interface. Chemical crosslinking in reducing conditions shows that disulfide bridges are involved in KCC2 dimerization. Moreover, we show that adding a tag to the C-terminus is detrimental to KCC2 function. We postulate that the conserved KCC2 C-ter may be at the interface of dimerization. Taken together, our findings highlight the flexible multi-domain structure of KCC2 with variable anchoring points at the dimerization interface and an important C-ter extremity providing the first in-depth functional architecture of KCC2

Multiple sclerosis management during the COVID-19 pandemic

Altres ajuts: The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. The development of standardized data collection as part of routine clinical care through Multiple Sclerosis Partners Advancing Technology and Health Solutions (MS PATHS) was developed and implemented at CC, JH, and CEMCAT in partnership with Biogen. Biogen did not have involvement in study design, data analysis or interpretation, or manuscript preparation.People with multiple sclerosis (MS) may be at higher risk for complications from the 2019 coronavirus (COVID-19) pandemic due to use of immunomodulatory disease modifying therapies (DMTs) and greater need for medical services. To evaluate risk factors for COVID-19 susceptibility and describe the pandemic's impact on healthcare delivery. Surveys sent to MS patients at Cleveland Clinic, Johns Hopkins, and Vall d'Hebron-Centre d'Esclerosi Múltiple de Catalunya in April and May 2020 collected information about comorbidities, DMTs, exposures, COVID-19 testing/outcomes, health behaviors, and disruptions to MS care. There were 3028/10,816 responders. Suspected or confirmed COVID-19 cases were more likely to have a known COVID-19 contact (odds ratio (OR): 4.38; 95% confidence interval (CI): 1.04, 18.54). In multivariable-adjusted models, people who were younger, had to work on site, had a lower education level, and resided in socioeconomically disadvantaged areas were less likely to follow social distancing guidelines. 4.4% reported changes to therapy plans, primarily delays in infusions, and 15.5% a disruption to rehabilitative services. Younger people with lower socioeconomic status required to work on site may be at higher exposure risk and are potential targets for educational intervention and work restrictions to limit exposure. Providers should be mindful of potential infusion delays and MS care disruption

Differential In Vitro Effects of Intravenous versus Oral Formulations of Silibinin on the HCV Life Cycle and Inflammation

Silymarin prevents liver disease in many experimental rodent models, and is the most popular botanical medicine consumed by patients with hepatitis C. Silibinin is a major component of silymarin, consisting of the flavonolignans silybin A and silybin B, which are insoluble in aqueous solution. A chemically modified and soluble version of silibinin, SIL, has been shown to potently reduce hepatitis C virus (HCV) RNA levels in vivo when administered intravenously. Silymarin and silibinin inhibit HCV infection in cell culture by targeting multiple steps in the virus lifecycle. We tested the hepatoprotective profiles of SIL and silibinin in assays that measure antiviral and anti-inflammatory functions. Both mixtures inhibited fusion of HCV pseudoparticles (HCVpp) with fluorescent liposomes in a dose-dependent fashion. SIL inhibited 5 clinical genotype 1b isolates of NS5B RNA dependent RNA polymerase (RdRp) activity better than silibinin, with IC50 values of 40–85 µM. The enhanced activity of SIL may have been in part due to inhibition of NS5B binding to RNA templates. However, inhibition of the RdRps by both mixtures plateaued at 43–73%, suggesting that the products are poor overall inhibitors of RdRp. Silibinin did not inhibit HCV replication in subgenomic genotype 1b or 2a replicon cell lines, but it did inhibit JFH-1 infection. In contrast, SIL inhibited 1b but not 2a subgenomic replicons and also inhibited JFH-1 infection. Both mixtures inhibited production of progeny virus particles. Silibinin but not SIL inhibited NF-κB- and IFN-B-dependent transcription in Huh7 cells. However, both mixtures inhibited T cell proliferation to similar degrees. These data underscore the differences and similarities between the intravenous and oral formulations of silibinin, which could influence the clinical effects of this mixture on patients with chronic liver diseases

Interneuron- and GABAA receptor-specific inhibitory synaptic plasticity in cerebellar purkinje cells

Inhibitory synaptic plasticity is important for shaping both neuronal excitability and network activity. Here we investigate the input and GABA(A) receptor subunit specificity of inhibitory synaptic plasticity by studying cerebellar interneuron-Purkinje cell (PC) synapses. Depolarizing PCs initiated a long-lasting increase in GABA-mediated synaptic currents. By stimulating individual interneurons, this plasticity was observed at somatodendritic basket cell synapses, but not at distal dendritic stellate cell synapses. Basket cell synapses predominantly express β2-subunit-containing GABA(A) receptors; deletion of the β2-subunit ablates this plasticity, demonstrating its reliance on GABA(A) receptor subunit composition. The increase in synaptic currents is dependent upon an increase in newly synthesized cell surface synaptic GABA(A) receptors and is abolished by preventing CaMKII phosphorylation of GABA(A) receptors. Our results reveal a novel GABA(A) receptor subunit- and input-specific form of inhibitory synaptic plasticity that regulates the temporal firing pattern of the principal output cells of the cerebellum

Correlating weathered, microphenocryst-rich, intermediate tephra: An approach combining bulk and single shard analyses from the Lepué Tephra, Chile and Argentina

Chemical correlation of intermediate tephra deposits using microanalytical data is problematic because (i) the phenocryst content of their component glass shards affects major and trace element analyses (ii) bulk chemistry can be affected by variations in mineral/lithic components across the fall-out, and (iii) weathering readily alters their composition. All of these problems affect the Lepué Tephra, a prominent marker horizon extensively distributed across the Los Lagos Region of Chile and the Chile-Argentina frontier in north-western Patagonia, which was erupted from Volcán Michinmahuida at c. 11000 cal a BP. Weathering of terrestrial cover-bed deposits in this hyper-humid depositional environment leaves only a few occurrences of the tephra which contain fresh glass shards for microbeam analysis, but their highly phenocrystic nature makes data interpretation difficult. Equally, leaching of mobile elements during weathering causes considerable compositional changes across the fall-out region and is evident in bulk sample analyses. Elements such as the REE and Y, generally regarded as immobile, show marked mobility. Within the REE, the development of M-type tetrad effects and positive Ce-anomalies result from a combination of dissolution/leaching of the REE from the bulk sample and retention by co-precipitation of Ce4+ on Fe-oxyhydroxides in this high-rainfall, hyper-humid, oxic environment. Chemical correlation of the Lepué Tephra is thus not straightforward. However, by careful consideration of the data for a limited range of elements, chemical correlation can be achieved using elements which (i) are incompatible in magmatic systems (and thus their ratios are unaffected by the presence of phenocrysts in single glass shard microbeam analysis) and (ii) are not mobilised in these weathering conditions. These elements are Zr, Hf, Nb, Ta and Th. Their ratios (i) allow for the comparison of single grain and bulk sample analyses, extending the geographic range over which data can be compared for the Lepué Tephra, (ii) provide a robust chemical correlation of this weathered, intermediate tephra deposit, enabling correlation even where elements traditionally considered immobile (REE, Y, and U) have been significantly mobilised, and (iii) allow the Lepué Tephra to be distinguished from other local tephra deposits. This combined analytical approach enables tephras that have been variably weathered to become useful marker beds over much wider geographical areas than previously feasible, thereby enhancing their tephrochronological application in Quaternary research