Congenital myasthenic syndrome in Golden Retrievers is associated with a novel COLQ mutation.

BackgroundCongenital myasthenic syndromes (CMSs) are a group of inherited disorders of neuromuscular transmission that may be presynaptic, synaptic, or postsynaptic. Causative mutations have been identified in 4 breeds including the Labrador Retriever, Jack Russell Terrier, Heideterrier, and Danish Pointing Dog.Hypothesis/objectiveClinical and genetic characterization of a neuromuscular disorder in Golden Retriever (GR) puppies.AnimalsFour GR puppies from California were evaluated for generalized muscle weakness beginning at weaning. Biological specimens were collected from the affected puppies, and familial information was obtained. Blood or buccal swabs were obtained from 63 unaffected GRs.MethodsComplete physical, neurological, electrodiagnostic, and histological evaluations and biochemical quantification of muscle acetylcholine receptors were performed. Polymerase chain reaction was used to amplify the 17 exons of COLQ, and sequences were obtained by Sanger sequencing. Variant frequency was assessed in unrelated GRs and a public database.ResultsClinical, neurological, and electrodiagnostic evaluations confirmed a disorder of neuromuscular transmission in a GR family. Sequencing of all exons and splice sites of a primary candidate gene, COLQ, identified a point mutation that predicts an amino acid substitution (G294R). The primary COLQ transcript was absent from affected muscle samples. All affected puppies were homozygous for the mutation, which was not detected outside this GR family or in other breeds.Conclusions and clinical importanceWe confirmed the diagnosis of a CMS in GR puppies and identified a novel COLQ mutation. The COLQ gene encodes the collagenous tail of acetylcholinesterase, the enzyme responsible for termination of skeletal muscle contraction by clearing acetylcholine at the neuromuscular junction. Clinicians and breeders should be aware of this CMS in GR puppies with an early onset of weakness

Modest Interference with Actin Dynamics in Primary T Cell Activation by Antigen Presenting Cells Preferentially Affects Lamellal Signaling

Dynamic subcellular distributions of signaling system components are critical regulators of cellular signal transduction through their control of molecular interactions. Understanding how signaling activity depends on such distributions and the cellular structures driving them is required for comprehensive insight into signal transduction. In the activation of primary murine T cells by antigen presenting cells (APC) signaling intermediates associate with various subcellular structures, prominently a transient, wide, and actin-associated lamellum extending from an interdigitated T cell:APC interface several micrometers into the T cell. While actin dynamics are well established as general regulators of cellular organization, their role in controlling signaling organization in primary T cell:APC couples and the specific cellular structures driving it is unresolved. Using modest interference with actin dynamics with a low concentration of Jasplakinolide as corroborated by costimulation blockade we show that T cell actin preferentially controls lamellal signaling localization and activity leading downstream to calcium signaling. Lamellal localization repeatedly related to efficient T cell function. This suggests that the transient lamellal actin matrix regulates T cell signaling associations that facilitate T cell activation

Using Patterns of Genetic Association to Elucidate Shared Genetic Etiologies Across Psychiatric Disorders

Twin studies indicate that latent genetic factors overlap across comorbid psychiatric disorders. In this study, we used a novel approach to elucidate shared genetic factors across psychiatric outcomes by clustering single nucleotide polymorphisms based on their genome-wide association patterns. We applied latent profile analysis (LPA) to p-values resulting from genome-wide association studies across three phenotypes: symptom counts of alcohol dependence (AD), antisocial personality disorder (ASP), and major depression (MD), using the European–American case-control genome-wide association study subsample of the collaborative study on the genetics of alcoholism (N = 1399). In the 3-class model, classes were characterized by overall low associations (85.6% of SNPs), relatively stronger association only with MD (6.8%), and stronger associations with AD and ASP but not with MD (7.6%), respectively. These results parallel the genetic factor structure identified in twin studies. The findings suggest that applying LPA to association results across multiple disorders may be a promising approach to identify the specific genetic etiologies underlying shared genetic variance

Nonclassic lipoid congenital adrenal hyperplasia masquerading as familial glucocorticoid deficiency

Context: Familial glucocorticoid deficiency (FGD) is an autosomal recessive disorder resulting from resistance to the action of ACTH on the adrenal cortex. Affected individuals are deficient in cortisol and, if untreated, are likely to succumb to hypoglycemia and/or overwhelming infection. Mutations of the ACTH receptor (MC2R) and the melanocortin 2 receptor accessory protein (MRAP), FGD types 1 and 2 respectively, account for approximately 45% of cases. Objective: A locus on chromosome 8 has previously been linked to the disease in three families, but no underlying gene defect has to date been identified. Design: The study design comprised single-nucleotide polymorphism genotyping and mutation detection. Setting: The study was conducted at secondary and tertiary referral centers. Patients: Eighty probands from families referred for investigation of the genetic cause of FGD participated in the study. Interventions: There were no interventions. Results: Analysis by single-nucleotide polymorphism array of the genotype of one individual with FGD previously linked to chromosome 8 revealed a large region of homozygosity encompassing the steroidogenic acute regulatory protein gene, STAR. We identified homozygous STAR mutations in this patient and his affected siblings. Screening of our total FGD patient cohort revealed homozygous STAR mutations in a further nine individuals from four other families. Conclusions: Mutations in STAR usually cause lipoid congenital adrenal hyperplasia, a disorder characterized by both gonadal and adrenal steroid deficiency. Our results demonstrate that certain mutations in STAR (R192C and the previously reported R188C) can present with a phenotype indistinguishable from that seen in FGD

Hantavirus Infection in the Republic of Georgia

We describe a laboratory-confirmed case of hantavirus infection in the Republic of Georgia. Limited information is available about hantavirus infections in the Caucasus, although the infection has been reported throughout Europe and Russia. Increasing awareness and active disease surveillance contribute to our improved understanding of the geographic range of this pathogen

Methylphenidate improves response inhibition but not reflection–impulsivity in children with attention deficit hyperactivity disorder (ADHD)

Impulsivity is a cardinal feature of attention deficit hyperactivity disorder (ADHD), which is thought to underlie many of the cognitive and behavioural symptoms associated with the disorder. Impairments on some measures of impulsivity have been shown to be responsive to pharmacotherapy. However, impulsivity is a multi-factorial construct and the degree to which different forms of impulsivity contribute to impairments in ADHD or respond to pharmacological treatments remains unclear.The aims of the study were to assess the effects of methylphenidate (MPH) on the performance of children with ADHD on measures of reflection-impulsivity and response inhibition and to compare with the performance of healthy volunteers.Twenty-one boys (aged 7-13 years) diagnosed with ADHD underwent a double-blind, placebo-controlled trial of MPH (0.5 mg/kg) during which they performed the Information Sampling Task (IST) and the Stop Signal Task. A healthy age- and education-matched control group was tested on the same measures without medication.Children with ADHD were impaired on measures of response inhibition, but did not demonstrate reflection-impulsivity on the IST. However, despite sampling a similar amount of information as their peers, the ADHD group made more poor decisions. MPH improved performance on measures of response inhibition and variability of response, but did not affect measures of reflection-impulsivity or quality of decision-making.MPH differentially affected two forms of impulsivity in children with ADHD and failed to ameliorate their poor decision-making on the information sampling test.</p

Dual Action of miR-125b As a Tumor Suppressor and OncomiR-22 Promotes Prostate Cancer Tumorigenesis

MicroRNAs (miRs) are a novel class of small RNA molecules, the dysregulation of which can contribute to cancer. A combinatorial approach was used to identify miRs that promote prostate cancer progression in a unique set of prostate cancer cell lines, which originate from the parental p69 cell line and extend to a highly tumorigenic/metastatic M12 subline. Together, these cell lines are thought to mimic prostate cancer progression in vivo. Previous network analysis and miR arrays suggested that the loss of hsa-miR-125b together with the overexpression of hsa-miR-22 could contribute to prostate tumorigenesis. The dysregulation of these two miRs was confirmed in human prostate tumor samples as compared to adjacent benign glandular epithelium collected through laser capture microdissection from radical prostatectomies. In fact, alterations in hsa-miR-125b expression appeared to be an early event in tumorigenesis. Reverse phase microarray proteomic analysis revealed ErbB2/3 and downstream members of the PI3K/AKT and MAPK/ERK pathways as well as PTEN to be protein targets differentially expressed in the M12 tumor cell compared to its parental p69 cell. Relevant luciferase+3’-UTR expression studies confirmed a direct interaction between hsa-miR-125b and ErbB2 and between hsa-miR-22 and PTEN. Restoration of hsa-miR-125b or inhibition of hsa-miR-22 expression via an antagomiR resulted in an alteration of M12 tumor cell behavior in vitro. Thus, the dual action of hsa-miR-125b as a tumor suppressor and hsa-miR-22 as an oncomiR contributed to prostate tumorigenesis by modulations in PI3K/AKT and MAPK/ERK signaling pathways, key pathways known to influence prostate cancer progression

Computational spatiotemporal analysis identifies WAVE2 and cofilin as joint regulators of costimulation-mediated T cell actin dynamics

Fluorescence microscopy is one of the most important tools in cell biology research and it provides spatial and temporal information to investigate regulatory systems inside cells. This technique can generate data in the form of signal intensities at thousands of positions resolved inside individual live cells; however, given extensive cell-to-cell variation, methods do not currently exist to assemble these data into three- or four-dimensional maps of protein concentration that can be compared across different cells and conditions. Here, we have developed one such method and applied it to investigate actin dynamics in T cell activation. Antigen recognition in T cells by the T cell receptor (TCR) is amplified by engagement of the costimulatory receptor CD28 and we have determined how CD28 modulates actin dynamics. We imaged actin and eight core actin regulators under conditions where CD28 in the context of a strong TCR signal was engaged or blocked to yield over a thousand movies. Our computational analysis identified diminished recruitment of the activator of actin nucleation WAVE2 and the actin severing protein cofilin to F-actin as the dominant difference upon costimulation blockade. Reconstitution of WAVE2 and cofilin activity restored the defect in actin signaling dynamics upon costimulation blockade. Thus we have developed and validated an approach to quantify protein distributions in time and space for analysis of complex regulatory systems

Probing the dynamics of O-GlcNAc glycosylation in the brain using quantitative proteomics

The addition of the monosaccharide beta-N-acetyl-D-glucosamine to proteins (O-GlcNAc glycosylation) is an intracellular, post-translational modification that shares features with phosphorylation. Understanding the cellular mechanisms and signaling pathways that regulate O-GlcNAc glycosylation has been challenging because of the difficulty of detecting and quantifying the modification. Here, we describe a new strategy for monitoring the dynamics of O-GlcNAc glycosylation using quantitative mass spectrometry-based proteomics. Our method, which we have termed quantitative isotopic and chemoenzymatic tagging (QUIC-Tag), combines selective, chemoenzymatic tagging of O-GlcNAc proteins with an efficient isotopic labeling strategy. Using the method, we detect changes in O-GlcNAc glycosylation on several proteins involved in the regulation of transcription and mRNA translocation. We also provide the first evidence that O-GlcNAc glycosylation is dynamically modulated by excitatory stimulation of the brain in vivo. Finally, we use electron-transfer dissociation mass spectrometry to identify exact sites of O-GlcNAc modification. Together, our studies suggest that O-GlcNAc glycosylation occurs reversibly in neurons and, akin to phosphorylation, may have important roles in mediating the communication between neurons