TAG1 regulates the endocytic trafficking and signaling of the semaphorin3A receptor complex.

Endocytic trafficking of membrane proteins is essential for neuronal structure and function. We show that Transient Axonal Glycoprotein 1 (TAG1 or CNTN2), a contactin-related adhesion molecule, plays a central role in the differential trafficking of components of the semaphorin3A (Sema3A) receptor complex into distinct endosomal compartments in murine spinal sensory neuron growth cones. The semaphorin3A receptor is composed of Neuropilin1 (NRP1), PlexinA4, and L1, with NRP1 being the ligand-binding component. TAG1 interacts with NRP1, causing a change in its association with L1 in the Sema3A response such that L1 is lost from the complex following Sema3A binding. Initially, however, L1 and NRP1 endocytose together and only become separated intracellularly, with NRP1 becoming associated with endosomes enriched in lipid rafts and colocalizing with TAG1 and PlexinA4. When TAG1 is missing, NRP1 and L1 fail to separate and NRP1 does not become raft associated; colocalization with PlexinA4 is reduced and Plexin signaling is not initiated. These observations identify a novel role for TAG1 in modulating the intracellular sorting of signaling receptor complexes

NrCAM modulates sonic hedgehog signalling by controlling smoothened translocation in the cilium

Objective: Cerebellar development involves a spurt of proliferation in external granule layer (EGL) in response to shh, causing granule neuron precursors (GNPs) to proliferate. These cells subsequently differentiate into granule neurons in the inner granule layer (IGL). F3, a CNTN family molecule, can interact with NrCAM to switch GNPs from proliferation to differentiation. We aim to identify the role of NrCAM in the sonic hedgehog response in GNPs. Methods: GNPs were extracted from wildtype and NrCAM mutant P5 cerebella using Percoll gradient centrifugation. Proliferation response to shh was measured using EdU in presence/absence of F3-Fc. GNPs treated with shh/SAG were stained with antibodies against Arl13b and smo to look for differences in cilia size and smo occupancy after different treatment times. Results: NrCAM-/- and wildtype GNPs both proliferated equally in response to shh. F3 was found to block the proliferation response in wildtype but not in NrCAM-/- GNPs. F3 also failed to affect proliferation in SmoA1 GNPs with a constitutively active smo suggesting that the F3-NrCAM mediated block lay upstream of Smo. NrCAM was detected in wildtype cilia and Smo localization was affected in NrCAM-/- GNPs. No differences in cilia length were observed. Conclusion: Our results suggest that NrCAM affects shh-mediated proliferation by controlling smo movement into the cilium

Long rallies and next rally performances in elite men's and women's badminton

The aim of the present study was twofold: (i) to identify contextual variables associated with the occurrence of long rallies while investigating time-related and technical parameters; and (ii) to identify performance differences between long rallies and the subsequent rally when accounting for match-context and the players' sex. The sample included 60 men's (n = 4,475 rallies) and 60 women's (n = 4,490 rallies) matches randomly selected from the 2015 World Badminton Super Series and World Championship (the final sample included long rallies that had an immediate next point played: n = 1,734 and n = 1,644 rallies for male and female players, respectively). The long rallies represented 19.4% (n = 867) and 16.5% (n = 822) of total rallies for male and female players, respectively. Long rallies were established using a two-step cluster model based on rally time and number of strokes for male (13-79s, 14-72 strokes) and female players (11-56s, 11-52 strokes). The variables collected were point outcome (when serving and receiving, winner, forced-error and unforced-error), number of strokes per rally, rally time, rest time, density, and time between strokes. The rallies were classified into different contexts (clusters) according to influencing factors with eight clusters for male players and three clusters for female players identified. Comparisons among clusters were conducted using Kruskal Wallis and one-way ANOVAs. Comparisons between long and immediate next points were conducted using the Wilcoxon tests for most variables and Crosstabs Command for point outcome and rallies (long and immediate next). Statistically significant differences were identified for both sexes among clusters only for time-related variables (i.e., rally time, rest time, density and time between strokes). In addition, a greater number of strokes, longer rally, rest time, and higher density were identified during long rallies compared with the immediate next rally for both men's and women's matches (p<0.05). The time between strokes during long rallies was significantly greater for male players during clusters 3, 5, 6, and 7 (p<0.05) and significantly lower for female players during all clusters (p<0.05). Significant relationships were identified between winning point outcome, and more unforced errors when serving during the immediate next rally (men's cluster 5 and women's cluster 2), and more winners when serving during the immediate next rally (men's cluster 6). The current study identified and characterised long rallies in elite men's and women's badminton matches highlighting the importance of sex and contextual factors on time-related and technical demands. Information obtained from these unique sequences of play (i.e., long and immediate next rallies) will assist coaches when modelling and simulating players' performances (i.e., physiologically and cognitively) during athlete preparation/competition

The role of Gpi-anchored axonal glycoproteins in neural development and neurological disorders.

This review article focuses on the Contactin (CNTN) subset of the Immunoglobulin supergene family (IgC2/FNIII molecules), whose components share structural properties (the association of Immunoglobulin type C2 with Fibronectin type III domains), as well as a general role in cell contact formation and axonal growth control. IgC2/FNIII molecules include 6 highly related components (CNTN 1-6), associated with the cell membrane via a Glycosyl Phosphatidyl Inositol (GPI)-containing lipid tail. Contactin 1 and Contactin 2 share ~50 (49.38)% identity at the aminoacid level. They are components of the cell surface, from which they may be released in soluble forms. They bind heterophilically to multiple partners in cis and in trans, including members of the related L1CAM family and of the Neurexin family Contactin-associated proteins (CNTNAPs or Casprs). Such interactions are important for organising the neuronal membrane, as well as for modulating the growth and pathfinding of axon tracts. In addition, they also mediate the functional maturation of axons by promoting their interactions with myelinating cells at the nodal, paranodal and juxtaparanodal regions. Such interactions also mediate differential ionic channels (both Na(+) and K(+)) distribution, which is of critical relevance in the generation of the peak-shaped action potential. Indeed, thanks to their interactions with Ankyrin G, Na(+) channels map within the nodal regions, where they drive axonal depolarization. However, no ionic channels are found in the flanking Contactin1-containing paranodal regions, where CNTN1 interactions with Caspr1 and with the Ig superfamily component Neurofascin 155 in cis and in trans, respectively, build a molecular barrier between the node and the juxtaparanode. In this region K(+) channels are clustered, depending upon molecular interactions with Contactin 2 and with Caspr2. In addition to these functions, the Contactins appear to have also a role in degenerative and inflammatory disorders: indeed Contactin 2 is involved in neurodegenerative disorders with a special reference to the Alzheimer disease, given its ability to work as a ligand of the Alzheimer Precursor Protein (APP), which results in increased Alzheimer Intracellular Domain (AICD) release in a γ-secretase-dependent manner. On the other hand Contactin-1 drives Notch signalling activation via the Hes pathway, which could be consistent with its ability to modulate neuroinflammation events, and with the possibility that Contactin 1-dependent interactions may participate to the pathogenesis of the Multiple Sclerosis and of other inflammatory disorders

Methodological standards, quality of reporting, and regulatory compliance in animal research on amyotrophic lateral sclerosis: a systematic review

Objectives The amyotrophic lateral sclerosis (ALS) research community was one of the first to adopt methodology guidelines to improve preclinical research reproducibility. We here present the results of a systematic review to investigate how the standards in this field changed over the 10-year period during which the guidelines were first published (2007) and updated (2010). Methods We searched for papers reporting ALS research on SOD1 (superoxide dismutase 1) mice published between 2005 and 2015 on the ISI Web of Science database, resulting in a sample of 569 papers to review, after triage. Two scores—one for methodological quality, one for regulatory compliance—were built from weighted sums of separate sets of items, and subjected to multivariable regression analysis, to assess how these related to publication year, type of study, country of origin and journal. Results Reporting standards improved over time. Of papers published after the first ALS guidelines were made public, fewer than 9% referred specifically to these. Of key research parameters, only three (genetic background, number of transgenes and group size) were reported in >50% of the papers. Information on housing conditions, randomisation and blinding was absent in over two-thirds of the papers. Group size was among the best reported parameters, but the majority reported using fewer than the recommended sample size and only two studies clearly justified group size. Conclusions General methodological standards improved gradually over a period of 8–10 years, but remained generally comparable with related fields with no specific guidelines, except with regard to severity. Only 11% of ALS studies were classified in the highest severity level (animals allowed to reach death or moribund stages), substantially below the proportion in studies of comparable neurodegenerative diseases such as Huntington’s. The existence of field-specific guidelines, although a welcome indication of concern, seems insufficient to ensure adherence to high methodological standards. Other mechanisms may be required to improve methodological and welfare standards

SER CRIANÇA COM CÂNCER NA BRINQUEDOTECA HOSPITALAR: UM ESTUDO EM MERLEAU-PONTY

Este estudo qualitativo, do tipo fenomenológico-existencial, envolve a temática da Educação Especial, no seu sentido amplo e específico e das brinquedotecas hospitalares. As pessoas que colaboram com nossa pesquisa foram crianças e ou adolescentes com câncer, acolhidas pela instituição ACACCI, que atende pacientes dessa esfera. Os objetivos visam compreender o que é ser uma criança com câncer, enquanto sujeito com necessidades educacionais especiais inseridas em uma brinquedoteca hospitalar, bem como de mostrar o como se revela a corporeidade, a experiência e a percepção desses sujeitos diante do brinquedo e do brincar. Para tal propósito, recorremos fundamentalmente ao marco teórico Merleau-Ponty (1984, 1999, 2006) e os modos como essa produção discursiva produziu atitudes na pesquisadora. Como instrumentos de pesquisa, utilizamos de base uma ferramenta denominada de Diário de Campo e foi nele que escrevemos descrições compreensivas, postamos desenhos, fotografias, diálogos etc. Falas de adulto são postados, desde que relacionadas ao nosso objetivo de pesquisa. Todo processo durou dezoito (18) encontros na brinquedoteca hospitalar da instituição. Analisando os conceitos de "corporeidade, a experiência e a percepção" (MERLEAU-PONTY, 1999), que foram vividos como movimentos indissociados, a criança foi então inserida no mundo e o brinquedo e a brincadeira, tudo em uma brinquedoteca hospitalar, que acabaram significando o ser existencial de comunicação. Ocorreu também um silêncio que pode ter sido a ausência da fala, mas desvelada na fala gestual - são as diversas formas de linguagem do ser criança e ou adolescente. Assim, sentimos a criança na totalidade: o corpo, ao perceber objetos (brinquedos) diante de si e de se posicionar frente a eles, pontuando uma "fenomenologia do brincar", através da experiência, da percepção e de inclusão de si e do outro - no mundo. Quanto às implicações do estudo, também buscamos demonstrar os caminhos possíveis aos pedagogos em geral, voluntários etc., profissionais responsáveis por esses espaços-tempos nos quais a criança é lançada à própria existência, diante da finitude da vida, quer seja no ambiente hospitalar, no domiciliar, escolar, comunitário etc

Crumbs2 mediates ventricular layer remodelling to form the spinal cord central canal

In the spinal cord, the central canal forms through a poorly understood process termed dorsal collapse that involves attrition and remodelling of pseudostratified ventricular layer (VL) cells. Here, we use mouse and chick models to show that dorsal ventricular layer (dVL) cells adjacent to dorsal midline Nestin(+) radial glia (dmNes+RG) down-regulate apical polarity proteins, including Crumbs2 (CRB2) and delaminate in a stepwise manner; live imaging shows that as one cell delaminates, the next cell ratchets up, the dmNes+RG endfoot ratchets down, and the process repeats. We show that dmNes+RG secrete a factor that promotes loss of cell polarity and delamination. This activity is mimicked by a secreted variant of Crumbs2 (CRB2S) which is specifically expressed by dmNes+RG. In cultured MDCK cells, CRB2S associates with apical membranes and decreases cell cohesion. Analysis of Crb2F/F/Nestin-Cre+/− mice, and targeted reduction of Crb2/CRB2S in slice cultures reveal essential roles for transmembrane CRB2 (CRB2TM) and CRB2S on VL cells and dmNes+RG, respectively. We propose a model in which a CRB2S–CRB2TM interaction promotes the progressive attrition of the dVL without loss of overall VL integrity. This novel mechanism may operate more widely to promote orderly progenitor delamination