Reliability of the Charcot-Marie-Tooth functional outcome measure

The CMT‐FOM is a 13‐item clinical outcome assessment (COA) that measures physical ability in adults with Charcot‐Marie‐Tooth disease (CMT). Test‐retest reliability, internal consistency and convergent validity have been established for the CMT‐FOM. This current study sought to establish inter‐rater reliability. Following an in‐person training of six international clinical evaluators we recruited 10 participants with genetically diagnosed CMT1A, (aged 18‐74 years, 6 female). Participants were evaluated using the CMT‐FOM over 2 days. Participants were given at least a 3 hour rest between evaluations, and were assessed twice each day. Following the provision of training by master trainers, all 13 items of the CMT‐FOM exhibited excellent inter‐rater reliability for raw scores (ICC1,1 0.825‐0.989) and z‐scores (ICC1,1 0.762‐0.969). Reliability of the CMT‐FOM total score was excellent (ICC1,1 0.983, 95% CI 0.958‐0.995). The CMT‐FOM is a reliable COA used by clinical evaluators internationally. The next steps are to establish further validation through psychometric evaluation of the CMT‐FOM in the Accelerate Clinical Trials in CMT (ACT‐CMT) study

Phenotypic Variability of Childhood Charcot-Marie-Tooth Disease

IMPORTANCE: Disease severity of childhood Charcot-Marie-Tooth disease (CMT) has not been extensively characterized, either within or between types of CMT to date. OBJECTIVE: To assess the variability of disease severity in a large cohort of children and adolescents with CMT. DESIGN, SETTING, AND PARTICIPANTS: A cross-sectional study was conducted among 520 children and adolescents aged 3 to 20 years at 8 universities and hospitals involved in the Inherited Neuropathies Consortium between August 6, 2009, and July 31, 2014, in Australia, Italy, the United Kingdom, and the United States. Data analysis was conducted from August 1, 2014, to December 1, 2015. MAIN OUTCOMES AND MEASURES: Scores on the Charcot-Marie-Tooth Disease Pediatric Scale (CMTPedS), a well-validated unidimensional clinical outcome measure to assess disease severity. This instrument includes 11 items assessing fine and gross motor function, sensation, and balance to produce a total score ranging from 0 (unaffected) to 44 (severely affected). RESULTS: Among the 520 participants (274 males) aged 3 to 20 years, CMT type 1A (CMT1A) was the most prevalent type (252 [48.5%]), followed by CMT2A (31 [6.0%]), CMT1B (15 [2.9%]), CMT4C (13 [2.5%]), and CMTX1 (10 [1.9%]). Disease severity ranged from 1 to 44 points on the CMTPedS (mean [SD], 21.5 [8.9]), with ankle dorsiflexion strength and functional hand dexterity test being most affected. Participants with CMT1B (mean [SD] CMTPedS score, 24.0 [7.4]), CMT2A (29.7 [7.1]), and CMT4C (29.8 [8.6]) were more severely affected than those with CMT1A (18.9 [7.7]) and CMTX1 (males: 15.3 [7.7]; females: 13.0 [3.6]) (P < .05). Scores on the CMTPedS tended to worsen principally during childhood (ages, 3-10 years) for participants with CMT4C and CMTX1 and predominantly during adolescence for those with CMT1B and CMT2A (ages, 11-20 years), while CMT1A worsened consistently throughout childhood and adolescence. For individual items, participants with CMT4C recorded more affected functional dexterity test scores than did those with all other types of CMT (P < .05). Participants with CMT1A and CMTX1 performed significantly better on the 9-hole peg test and balance test than did those with all other types of CMT (P < .05). Participants with CMT2A had the weakest grip strength (P < .05), while those with CMT2A and CMT4C exhibited the weakest ankle plantarflexion and dorsiflexion strength, as well as the lowest long jump and 6-minute walk test distances (P < .05). Multiple regression modeling identified increasing age (r = 0.356, β = 0.617, P < .001) height (r = 0.251, β = 0.309, P = .002), self-reported foot pain (r = 0.162, β = .114, P = .009), and self-reported hand weakness (r = 0.243, β = 0.203, P < .001) as independent predictors of disease severity. CONCLUSIONS AND RELEVANCE: These results highlight the phenotypic variability within CMT genotypes and mutation-specific manifestations between types. This study has identified distinct functional limitations and self-reported impairments to target in future therapeutic trials

The Origin of GPCRs: Identification of Mammalian like Rhodopsin, Adhesion, Glutamate and Frizzled GPCRs in Fungi

G protein-coupled receptors (GPCRs) in humans are classified into the five main families named Glutamate, Rhodopsin, Adhesion, Frizzled and Secretin according to the GRAFS classification. Previous results show that these mammalian GRAFS families are well represented in the Metazoan lineages, but they have not been shown to be present in Fungi. Here, we systematically mined 79 fungal genomes and provide the first evidence that four of the five main mammalian families of GPCRs, namely Rhodopsin, Adhesion, Glutamate and Frizzled, are present in Fungi and found 142 novel sequences between them. Significantly, we provide strong evidence that the Rhodopsin family emerged from the cAMP receptor family in an event close to the split of Opisthokonts and not in Placozoa, as earlier assumed. The Rhodopsin family then expanded greatly in Metazoans while the cAMP receptor family is found in 3 invertebrate species and lost in the vertebrates. We estimate that the Adhesion and Frizzled families evolved before the split of Unikonts from a common ancestor of all major eukaryotic lineages. Also, the study highlights that the fungal Adhesion receptors do not have N-terminal domains whereas the fungal Glutamate receptors have a broad repertoire of mammalian-like N-terminal domains. Further, mining of the close unicellular relatives of the Metazoan lineage, Salpingoeca rosetta and Capsaspora owczarzaki, obtained a rich group of both the Adhesion and Glutamate families, which in particular provided insight to the early emergence of the N-terminal domains of the Adhesion family. We identified 619 Fungi specific GPCRs across 79 genomes and revealed that Blastocladiomycota and Chytridiomycota phylum have Metazoan-like GPCRs rather than the GPCRs specific for Fungi. Overall, this study provides the first evidence of the presence of four of the five main GRAFS families in Fungi and clarifies the early evolutionary history of the GPCR superfamily

Inositol Hexakisphosphate-Induced Autoprocessing of Large Bacterial Protein Toxins

Large bacterial protein toxins autotranslocate functional effector domains to the eukaryotic cell cytosol, resulting in alterations to cellular functions that ultimately benefit the infecting pathogen. Among these toxins, the clostridial glucosylating toxins (CGTs) produced by Gram-positive bacteria and the multifunctional-autoprocessing RTX (MARTX) toxins of Gram-negative bacteria have distinct mechanisms for effector translocation, but a shared mechanism of post-translocation autoprocessing that releases these functional domains from the large holotoxins. These toxins carry an embedded cysteine protease domain (CPD) that is activated for autoprocessing by binding inositol hexakisphosphate (InsP6), a molecule found exclusively in eukaryotic cells. Thus, InsP6-induced autoprocessing represents a unique mechanism for toxin effector delivery specifically within the target cell. This review summarizes recent studies of the structural and molecular events for activation of autoprocessing for both CGT and MARTX toxins, demonstrating both similar and potentially distinct aspects of autoprocessing among the toxins that utilize this method of activation and effector delivery

Natural history of Charcot-Marie-Tooth disease during childhood

OBJECTIVE: To determine the rate of disease progression in a longitudinal natural history study of children with Charcot-Marie-Tooth disease (CMT). METHODS: 206 (103 female) participants aged 3-20 years enrolled in the Inherited Neuropathies Consortium were assessed at baseline and 2-years. Demographic, anthropometric, and diagnostic information were collected. Disease progression was assessed with the CMT Pediatric Scale (CMTPedS), a reliable Rasch-built linearly weighted disability scale evaluating fine and gross motor function, strength, sensation, and balance. RESULTS: On average CMTPedS Total scores progressed at a rate of 2.4±4.9 over 2-years (14% change from baseline, p<0.001). There was no difference between males and females (mean difference 0.5, 95%CI -0.9 to 1.9, p=0.49). The most responsive CMTPedS items were dorsiflexion strength (z-score change: -0.3, 95% CI -0.6 to -0.05, p=0.02), balance (z-score change: -1.0, 95% CI -1.9 to -0.09, p=0.03), and long jump (z-score change: -0.4, 95% CI -0.7 to -0.02, p=0.04). Of the most common genetic subtypes, 111 participants with CMT1A/PMP22 duplication progressed by 1.8±4.2 (12% change from baseline, p<0.001), nine participants with CMT1B/MPZ mutation progressed by 2.2±5.1 (11% change), six participants with CMT2A/MFN2 mutation progressed by 6.2±7.9 (23% change), and seven participants with CMT4C/SH3TC2 mutations progressed by 3.0±4.5 (12% change). Participants with CMT2A progressed faster than CMT1A (mean difference -4.4, 95%CI -8.1 to -0.8, p=0.02). Children with CMT1A progressed consistently through early childhood (3-10 years) and adolescence (11-20 years) (mean difference 1.1, 95%CI -0.6 to 2.7, p=0.19) while CMT2A appeared to progress faster during early childhood than adolescence (mean difference 10.0, 95%CI -2.2 to 22.2, p=0.08). INTERPRETATION: Using the CMTPedS as an outcome measure of disease severity, children with CMT progress at a significant rate over 2-years. Understanding the rate at which children with CMT deteriorate is essential for adequately powering trials of disease-modifying interventions. This article is protected by copyright. All rights reserved

Rab11 and Actin Cytoskeleton Participate in Giardia lamblia Encystation, Guiding the Specific Vesicles to the Cyst Wall

The encystation process is crucial for survival and transmission of Giardia lamblia to new hosts. During this process, vesicular trafficking and the cytoskeleton play important roles. In eukaryotic cells, intracellular transport is regulated by proteins, including Rab-GTPases and SNAREs, which regulate vesicle formation along with recognition of and binding to the target membrane. Cytoskeletal structures are also involved in these processes. In this study, we demonstrate the participation of Rab11 in the transport of encystation-specific vesicles (ESVs). Additionally, we demonstrate that disruption of actin microfilaments affects ESVs transport. The modification of actin dynamics was also correlated with a reduction in rab11 and cwp1 expression. Furthermore, down-regulation of rab11 mRNA by a specific hammerhead ribozyme caused nonspecific localization of CWP1. We thus provide new information about the molecular machinery that regulates Giardia lamblia encystation. Given our findings, Rab11 and actin may be useful targets to block Giardia encystation

The Adhesion GPCR GPR125 is specifically expressed in the choroid plexus and is upregulated following brain injury

<p>Abstract</p> <p>Background</p> <p>GPR125 belongs to the family of <it>Adhesion </it>G protein-coupled receptors (GPCRs). A single copy of GPR125 was found in many vertebrate genomes. We also identified a <it>Drosophila </it>sequence, DmCG15744, which shares a common ancestor with the entire Group III of <it>Adhesio</it>n GPCRs, and also contains Ig, LRR and HBD domains which were observed in mammalian GPR125.</p> <p>Results</p> <p>We found specific expression of GPR125 in cells of the choroid plexus using <it>in situ </it>hybridization and protein-specific antibodies and combined <it>in situ</it>/immunohistochemistry co-localization using cytokeratin, a marker specific for epithelial cells. Induction of inflammation by LPS did not change GPR125 expression. However, GPR125 expression was transiently increased (almost 2-fold) at 4 h after traumatic brain injury (TBI) followed by a decrease (approximately 4-fold) from 2 days onwards in the choroid plexus as well as increased expression (2-fold) in the hippocampus that was delayed until 1 day after injury.</p> <p>Conclusion</p> <p>These findings suggest that GPR125 plays a functional role in choroidal and hippocampal response to injury.</p

Xpf and Not the Fanconi Anaemia Proteins or Rev3 Accounts for the Extreme Resistance to Cisplatin in Dictyostelium discoideum

Organisms like Dictyostelium discoideum, often referred to as DNA damage “extremophiles”, can survive exposure to extremely high doses of radiation and DNA crosslinking agents. These agents form highly toxic DNA crosslinks that cause extensive DNA damage. However, little is known about how Dictyostelium and the other “extremophiles” can tolerate and repair such large numbers of DNA crosslinks. Here we describe a comprehensive genetic analysis of crosslink repair in Dictyostelium discoideum. We analyse three gene groups that are crucial for a replication-coupled repair process that removes DNA crosslinks in higher eukarya: The Fanconi anaemia pathway (FA), translesion synthesis (TLS), and nucleotide excision repair. Gene disruption studies unexpectedly reveal that the FA genes and the TLS enzyme Rev3 play minor roles in tolerance to crosslinks in Dictyostelium. However, disruption of the Xpf nuclease subcomponent results in striking hypersensitivity to crosslinks. Genetic interaction studies reveal that although Xpf functions with FA and TLS gene products, most Xpf mediated repair is independent of these two gene groups. These results suggest that Dictyostelium utilises a distinct Xpf nuclease-mediated repair process to remove crosslinked DNA. Other DNA damage–resistant organisms and chemoresistant cancer cells might adopt a similar strategy to develop resistance to DNA crosslinking agents

Pleiotropic Roles of a Ribosomal Protein in Dictyostelium discoideum

The cell cycle phase at starvation influences post-starvation differentiation and morphogenesis in Dictyostelium discoideum. We found that when expressed in Saccharomyces cerevisiae, a D. discoideum cDNA that encodes the ribosomal protein S4 (DdS4) rescues mutations in the cell cycle genes cdc24, cdc42 and bem1. The products of these genes affect morphogenesis in yeast via a coordinated moulding of the cytoskeleton during bud site selection. D. discoideum cells that over- or under-expressed DdS4 did not show detectable changes in protein synthesis but displayed similar developmental aberrations whose intensity was graded with the extent of over- or under-expression. This suggested that DdS4 might influence morphogenesis via a stoichiometric effect – specifically, by taking part in a multimeric complex similar to the one involving Cdc24p, Cdc42p and Bem1p in yeast. In support of the hypothesis, the S. cerevisiae proteins Cdc24p, Cdc42p and Bem1p as well as their D. discoideum cognates could be co-precipitated with antibodies to DdS4. Computational analysis and mutational studies explained these findings: a C-terminal domain of DdS4 is the functional equivalent of an SH3 domain in the yeast scaffold protein Bem1p that is central to constructing the bud site selection complex. Thus in addition to being part of the ribosome, DdS4 has a second function, also as part of a multi-protein complex. We speculate that the existence of the second role can act as a safeguard against perturbations to ribosome function caused by spontaneous variations in DdS4 levels