65 research outputs found
AdS_4/CFT_3 -- Squashed, Stretched and Warped
We use group theoretic methods to calculate the spectrum of short multiplets
around the extremum of N=8 gauged supergravity potential which possesses N=2
supersymmetry and SU(3) global symmetry. Upon uplifting to M-theory, it
describes a warped product of AdS_4 and a certain squashed and stretched
7-sphere. We find quantum numbers in agreement with those of the gauge
invariant operators in the N=2 superconformal Chern-Simons theory recently
proposed to be the dual of this M-theory background. This theory is obtained
from the U(N)xU(N) theory through deforming the superpotential by a term
quadratic in one of the superfields. To construct this model explicitly, one
needs to employ monopole operators whose complete understanding is still
lacking. However, for the U(2)xU(2) gauge theory we make a proposal for the
form of the monopole operators which has a number of desired properties. In
particular, this proposal implies enhanced symmetry of the U(2)xU(2) ABJM
theory for k=1,2; it makes its similarity to and subtle difference from the BLG
theory quite explicit.Comment: 32 pages, v2: references added, minor changes, v3: some
clarifications, published versio
The CACNA1B R1389H variant is not associated with myoclonus-dystonia in a large European multicentric cohort.
Myoclonus-dystonia (M-D) is a very rare movement disorder, caused in ∼30-50% of cases by mutations in SGCE. The CACNA1B variant c.4166G>A; (p.R1389H) was recently reported as the likely causative mutation in a single 3-generation Dutch pedigree with five subjects affected by a unique dominant M-D syndrome and cardiac arrhythmias. In an attempt to replicate this finding, we assessed by direct sequencing the frequency of CACNA1B c.4166G>A; (p.R1389H) in a cohort of 520 M-D cases, in which SGCE mutations had been previously excluded. A total of 146 cases (28%) had a positive family history of M-D. The frequency of the variant was also assessed in 489 neurologically healthy controls and in publicly available data sets of genetic variation (1000 Genomes, Exome Variant Server and Exome Aggregation Consortium). The variant was detected in a single sporadic case with M-D, but in none of the 146 probands with familial M-D. Overall, the variant was present at comparable frequencies in M-D cases (1 out of 520; 0.19%) and healthy controls (1 out of 489; 0.2%). A similar frequency of the variant was also reported in all publicly available databases. These results do not support a causal association between the CACNA1B c.4166G>A; (p.R1389H) variant and M-D
Charges of Monopole Operators in Chern-Simons Yang-Mills Theory
We calculate the non-abelian R-charges of BPS monopole operators in
three-dimensional gauge theories with N=3 supersymmetry. This class of models
includes ABJM theory, the proposed gauge theory dual of M-theory on AdS_4 x
S^7/Z_k, as a special case. In the UV limit of the N=3 theories the Yang-Mills
coupling becomes weak and the monopole operators are described by classical
backgrounds. This allows us to find their SU(2)_R charges in a one-loop
computation which by virtue of the non-renormalization of non-abelian R-charges
yields the exact result for any value of the coupling. The spectrum of SU(2)_R
charges is found by quantizing the SU(2)/U(1) collective coordinate of the BPS
background, whose dynamics is that of a charged particle on a sphere with a
Wess-Zumino term representing a magnetic monopole at its center. If the
Wess-Zumino coefficient is h, then the smallest possible SU(2)_R representation
for BPS monopole operators has spin |h|/2. We find, in agreement with earlier
proposals, that h is proportional to the sum of the U(1)_R charges of all the
fermion fields weighted by the effective monopole charges determined by their
gauge representations. The field content of ABJM theory is such that h=0. This
proves for any Chern-Simons level k the existence of monopole operators which
are singlets under all global symmetries and have vanishing scaling dimensions.
These operators are essential for matching the spectrum of the ABJM theory with
supergravity and for the supersymmetry enhancement to N=8.Comment: 31 pages, 3 figures, v2: reference added, discussion of collective
coordinate wave-function adde
Review of AdS/CFT Integrability, Chapter IV.3: N=6 Chern-Simons and Strings on AdS4xCP3
We review the duality and integrability of N=6 superconformal Chern-Simons
theory in three dimensions and IIA superstring theory on the background
AdS4xCP3. We introduce both of these models and describe how their degrees of
freedom are mapped to excitations of a long-range integrable spin-chain.
Finally, we discuss the properties of the Bethe equations, the S-matrix and the
algebraic curve that are special to this correspondence and differ from the
case of N=4 SYM theory and strings on AdS5xS5.Comment: 22 pages, see also overview article arXiv:1012.3982, v2: references
to other chapters updated, v3: references added, v4: brief discussion of
giant magnons added, further minor changes, published version, v5: union of
v3 and v4 because changes made in v3 were accidentally lost in v
Polygenic Resilience Modulates the Penetrance of Parkinson Disease Genetic Risk Factors
peer reviewedObjective: The aim of the current study is to understand why some individuals avoid developing Parkinson disease (PD) despite being at relatively high genetic risk, using the largest datasets of individual-level genetic data available. Methods: We calculated polygenic risk score to identify controls and matched PD cases with the highest burden of genetic risk for PD in the discovery cohort (International Parkinson's Disease Genomics Consortium, 7,204 PD cases and 9,412 controls) and validation cohorts (Comprehensive Unbiased Risk Factor Assessment for Genetics and Environment in Parkinson's Disease, 8,968 cases and 7,598 controls; UK Biobank, 2,639 PD cases and 14,301 controls; Accelerating Medicines Partnership–Parkinson's Disease Initiative, 2,248 cases and 2,817 controls). A genome-wide association study meta-analysis was performed on these individuals to understand genetic variation associated with resistance to disease. We further constructed a polygenic resilience score, and performed multimarker analysis of genomic annotation (MAGMA) gene-based analyses and functional enrichment analyses. Results: A higher polygenic resilience score was associated with a lower risk for PD (β = −0.054, standard error [SE] = 0.022, p = 0.013). Although no single locus reached genome-wide significance, MAGMA gene-based analyses nominated TBCA as a putative gene. Furthermore, we estimated the narrow-sense heritability associated with resilience to PD (h2 = 0.081, SE = 0.035, p = 0.0003). Subsequent functional enrichment analysis highlighted histone methylation as a potential pathway harboring resilience alleles that could mitigate the effects of PD risk loci. Interpretation: The present study represents a novel and comprehensive assessment of heritable genetic variation contributing to PD resistance. We show that a genetic resilience score can modify the penetrance of PD genetic risk factors and therefore protect individuals carrying a high-risk genetic burden from developing PD. ANN NEUROL 202
Quantifying Absolute Neutralization Titers against SARS-CoV-2 by a Standardized Virus Neutralization Assay Allows for CrossCohort Comparisons of COVID-19 Sera
The global coronavirus disease 2019 (COVID-19) pandemic has mobilized efforts to develop vaccines and antibody-based therapeutics, including convalescent-phase plasma therapy, that inhibit viral entry by inducing or transferring neutralizing antibodies (nAbs) against the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike glycoprotein (CoV2-S). However, rigorous efficacy testing requires extensive screening with live virus under onerous biosafety level 3 (BSL3) conditions, which limits high-throughput screening of patient and vaccine sera. Myriad BSL2-compatible surrogate virus neutralization assays (VNAs) have been developed to overcome this barrier. Yet, there is marked variability between VNAs and how their results are presented, making intergroup comparisons difficult. To address these limitations, we developed a standardized VNA using CoV2-S pseudotyped particles (CoV2pp) based on vesicular stomatitis virus bearing the Renilla luciferase gene in place of its G glyco-protein (VSVDG); this assay can be robustly produced at scale and generate accurate neutralizing titers within 18 h postinfection. Our standardized CoV2pp VNA showed a strong positive correlation with CoV2-S enzyme-linked immunosorbent assay (ELISA) results and live-virus neutralizations in confirmed convalescent-patient sera. Three independent groups subsequently validated our standardized CoV2pp VNA (n . 120). Our data (i) show that absolute 50% inhibitory concentration (absIC50), absIC80, and absIC90 values can be legitimately compared across diverse cohorts, (ii) highlight the substantial but consistent variability in neutralization potency across these cohorts, and (iii) support the use of the absIC80 as a more meaningful metric for assessing the neutralization potency of a vaccine or convalescent-phase sera. Lastly, we used our CoV2pp in a screen to identify ultrapermissive 293T clones that stably express ACE2 or ACE2 plus TMPRSS2. When these are used in combination with our CoV2pp, we can produce CoV2pp sufficient for 150,000 standardized VNAs/week. IMPORTANCE Vaccines and antibody-based therapeutics like convalescent-phase plasma therapy are premised upon inducing or transferring neutralizing antibodies that inhibit SARS-CoV-2 entry into cells. Virus neutralization assays (VNAs) for measuring neutralizing antibody titers (NATs) are an essential part of determining vaccine or therapeutic efficacy. However, such efficacy testing is limited by the inherent dangers of working with the live virus, which requires specialized high-level biocontainment facilities. We there-fore developed a standardized replication-defective pseudotyped particle system that mimics the entry of live SARS-CoV-2. This tool allows for the safe and efficient measurement of NATs, determination of other forms of entry inhibition, and thorough investigation of virus entry mechanisms. Four independent labs across the globe validated our standardized VNA using diverse cohorts. We argue that a standardized and scalable assay is necessary for meaningful comparisons of the myriad of vaccines and antibody-based therapeutics becoming available. Our data provide generalizable metrics for assessing their efficacy.Fil: Oguntuyo, Kasopefoluwa. Icahn School of Medicine at Mount Sinai; Estados UnidosFil: Stevens, Christian S.. Icahn School of Medicine at Mount Sinai; Estados UnidosFil: Hung, Chuan Tien. Icahn School of Medicine at Mount Sinai; Estados UnidosFil: Ikegame, Satoshi. Icahn School of Medicine at Mount Sinai; Estados UnidosFil: Acklin, Joshua A.. Icahn School of Medicine at Mount Sinai; Estados UnidosFil: Kowdle, Shreyas S.. Icahn School of Medicine at Mount Sinai; Estados UnidosFil: Carmichael, Jillian C.. Icahn School of Medicine at Mount Sinai; Estados UnidosFil: Chiu, Hsin Ping. Icahn School of Medicine at Mount Sinai; Estados UnidosFil: Azarm, Kristopher D.. Icahn School of Medicine at Mount Sinai; Estados UnidosFil: Haas, Griffin D.. Icahn School of Medicine at Mount Sinai; Estados UnidosFil: Amanat, Fatima. Icahn School of Medicine at Mount Sinai; Estados UnidosFil: Klingler, Jéromine. Icahn School of Medicine at Mount Sinai; Estados UnidosFil: Baine, Ian. Icahn School of Medicine at Mount Sinai; Estados UnidosFil: Arinsburg, Suzanne. Icahn School of Medicine at Mount Sinai; Estados UnidosFil: Bandres, Juan C.. Icahn School of Medicine at Mount Sinai; Estados UnidosFil: Siddiquey, Mohammed N. A.. Icahn School of Medicine at Mount Sinai; Estados UnidosFil: Schilke, Robert M.. Icahn School of Medicine at Mount Sinai; Estados UnidosFil: Woolard, Matthew D.. State University of Louisiana; Estados UnidosFil: Zhang, Hongbo. State University of Louisiana; Estados UnidosFil: Duty, Andrew J.. Icahn School of Medicine at Mount Sinai; Estados UnidosFil: Kraus, Thomas A.. Icahn School of Medicine at Mount Sinai; Estados UnidosFil: Moran, Thomas M.. Icahn School of Medicine at Mount Sinai; Estados UnidosFil: Tortorella, Domenico. Icahn School of Medicine at Mount Sinai; Estados UnidosFil: Lim, Jean K.. Icahn School of Medicine at Mount Sinai; Estados UnidosFil: Gamarnik, Andrea Vanesa. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentina. Icahn School of Medicine at Mount Sinai; Estados UnidosFil: Hioe, Catarina E.. Icahn School of Medicine at Mount Sinai; Estados UnidosFil: Zolla Pazner, Susan. Icahn School of Medicine at Mount Sinai; Estados UnidosFil: Ivanov, Stanimir S.. State University of Louisiana; Estados UnidosFil: Kamil, Jeremy. State University of Louisiana; Estados UnidosFil: Krammer, Florian. Icahn School of Medicine at Mount Sinai; Estados UnidosFil: Lee, Benhur. Icahn School of Medicine at Mount Sinai; Estados UnidosFil: Ojeda, Diego Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Biomédicas en Retrovirus y Sida. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Biomédicas en Retrovirus y Sida; ArgentinaFil: González López Ledesma, María Mora. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Costa Navarro, Guadalupe Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Pallarés, H. M.. No especifíca;Fil: Sanchez, Lautaro Nicolas. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Perez, P.. No especifíca;Fil: Ostrowsk, M.. No especifíca;Fil: Villordo, S. M.. No especifíca;Fil: Alvarez, D. E.. No especifíca;Fil: Caramelo, J. J.. No especifíca;Fil: Carradori, J.. No especifíca;Fil: Yanovsky, M. J.. No especifíca
Identification of novel risk loci, causal insights, and heritable risk for Parkinson's disease: a meta-analysis of genome-wide association studies
Background Genome-wide association studies (GWAS) in Parkinson's disease have increased the scope of biological knowledge about the disease over the past decade. We aimed to use the largest aggregate of GWAS data to identify novel risk loci and gain further insight into the causes of Parkinson's disease. Methods We did a meta-analysis of 17 datasets from Parkinson's disease GWAS available from European ancestry samples to nominate novel loci for disease risk. These datasets incorporated all available data. We then used these data to estimate heritable risk and develop predictive models of this heritability. We also used large gene expression and methylation resources to examine possible functional consequences as well as tissue, cell type, and biological pathway enrichments for the identified risk factors. Additionally, we examined shared genetic risk between Parkinson's disease and other phenotypes of interest via genetic correlations followed by Mendelian randomisation. Findings Between Oct 1, 2017, and Aug 9, 2018, we analysed 7·8 million single nucleotide polymorphisms in 37 688 cases, 18 618 UK Biobank proxy-cases (ie, individuals who do not have Parkinson's disease but have a first degree relative that does), and 1·4 million controls. We identified 90 independent genome-wide significant risk signals across 78 genomic regions, including 38 novel independent risk signals in 37 loci. These 90 variants explained 16–36% of the heritable risk of Parkinson's disease depending on prevalence. Integrating methylation and expression data within a Mendelian randomisation framework identified putatively associated genes at 70 risk signals underlying GWAS loci for follow-up functional studies. Tissue-specific expression enrichment analyses suggested Parkinson's disease loci were heavily brain-enriched, with specific neuronal cell types being implicated from single cell data. We found significant genetic correlations with brain volumes (false discovery rate-adjusted p=0·0035 for intracranial volume, p=0·024 for putamen volume), smoking status (p=0·024), and educational attainment (p=0·038). Mendelian randomisation between cognitive performance and Parkinson's disease risk showed a robust association (p=8·00 × 10−7). Interpretation These data provide the most comprehensive survey of genetic risk within Parkinson's disease to date, to the best of our knowledge, by revealing many additional Parkinson's disease risk loci, providing a biological context for these risk factors, and showing that a considerable genetic component of this disease remains unidentified. These associations derived from European ancestry datasets will need to be followed-up with more diverse data. Funding The National Institute on Aging at the National Institutes of Health (USA), The Michael J Fox Foundation, and The Parkinson's Foundation (see appendix for full list of funding sources)
Regulatory sites for splicing in human basal ganglia are enriched for disease-relevant information
Genome-wide association studies have generated an increasing number of common genetic variants associated with neurological and psychiatric disease risk. An improved understanding of the genetic control of gene expression in human brain is vital considering this is the likely modus operandum for many causal variants. However, human brain sampling complexities limit the explanatory power of brain-related expression quantitative trait loci (eQTL) and allele-specific expression (ASE) signals. We address this, using paired genomic and transcriptomic data from putamen and substantia nigra from 117 human brains, interrogating regulation at different RNA processing stages and uncovering novel transcripts. We identify disease-relevant regulatory loci, find that splicing eQTLs are enriched for regulatory information of neuron-specific genes, that ASEs provide cell-specific regulatory information with evidence for cellular specificity, and that incomplete annotation of the brain transcriptome limits interpretation of risk loci for neuropsychiatric disease. This resource of regulatory data is accessible through our web server, http://braineacv2.inf.um.es/
Genome sequencing analysis identifies new loci associated with Lewy body dementia and provides insights into its genetic architecture
The genetic basis of Lewy body dementia (LBD) is not well understood. Here, we performed whole-genome sequencing in large cohorts of LBD cases and neurologically healthy controls to study the genetic architecture of this understudied form of dementia, and to generate a resource for the scientific community. Genome-wide association analysis identified five independent risk loci, whereas genome-wide gene-aggregation tests implicated mutations in the gene GBA. Genetic risk scores demonstrate that LBD shares risk profiles and pathways with Alzheimer's disease and Parkinson's disease, providing a deeper molecular understanding of the complex genetic architecture of this age-related neurodegenerative condition
LRRK2 Biology from structure to dysfunction: research progresses, but the themes remain the same
Since the discovery of leucine-rich repeat kinase 2 (LRRK2) as a protein that is likely central to the aetiology of Parkinson's disease, a considerable amount of work has gone into uncovering its basic cellular function. This effort has led to the implication of LRRK2 in a bewildering range of cell biological processes and pathways, and probable roles in a number of seemingly unrelated medical conditions. In this review we summarise current knowledge of the basic biochemistry and cellular function of LRRK2. Topics covered include the identification of phosphorylation substrates of LRRK2 kinase activity, in particular Rab proteins, and advances in understanding the activation of LRRK2 kinase activity via dimerisation and association with membranes, especially via interaction with Rab29. We also discuss biochemical studies that shed light on the complex LRRK2 GTPase activity, evidence of roles for LRRK2 in a range of cell signalling pathways that are likely cell type specific, and studies linking LRRK2 to the cell biology of organelles. The latter includes the involvement of LRRK2 in autophagy, endocytosis, and processes at the trans-Golgi network, the endoplasmic reticulum and also key microtubule-based cellular structures. We further propose a mechanism linking LRRK2 dimerisation, GTPase function and membrane recruitment with LRRK2 kinase activation by Rab29. Together these data paint a picture of a research field that in many ways is moving forward with great momentum, but in other ways has not changed fundamentally. Many key advances have been made, but very often they seem to lead back to the same places
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