Imaging gene and environmental effects on cerebellum in Attention-Deficit/Hyperactivity Disorder and typical development

AbstractThis study investigates the effects of XKR4, a recently identified candidate gene for Attention-Deficit/Hyperactivity Disorder (ADHD), birth weight, and their interaction on brain volume in ADHD. XKR4 is expressed in cerebellum and low birth weight has been associated both with changes in cerebellum and with ADHD, probably due to its relation with prenatal adversity. Anatomical MRI scans were acquired in 58 children with ADHD and 64 typically developing controls and processed to obtain volumes of cerebrum, cerebellum and gray and white matter in each structure. DNA was collected from saliva. Analyses including data on birth weight were conducted in a subset of 37 children with ADHD and 51 controls where these data were retrospectively collected using questionnaires. There was an interaction between genotype and birth weight for cerebellum gray matter volume (p=.020). The combination of homozygosity for the G-allele (the allele previously found to be overtransmitted in ADHD) and higher birth weight was associated with smaller volume. Furthermore, birth weight was positively associated with cerebellar white matter volume in controls, but not ADHD (interaction: p=.021). The interaction of genotype with birth weight affecting cerebellum gray matter is consistent with models that emphasize increased influence of genetic risk-factors in an otherwise favorable prenatal environment. The absence of an association between birth weight and cerebellum white matter volume in ADHD suggests that other genetic or environmental effects may be at play, unrelated to XKR4. These results underscore the importance of considering environmental effects in imaging genetics studies

An Ancient Duplication of Exon 5 in the Snap25 Gene Is Required for Complex Neuronal Development/Function

Alternative splicing is an evolutionary innovation to create functionally diverse proteins from a limited number of genes. SNAP-25 plays a central role in neuroexocytosis by bridging synaptic vesicles to the plasma membrane during regulated exocytosis. The SNAP-25 polypeptide is encoded by a single copy gene, but in higher vertebrates a duplication of exon 5 has resulted in two mutually exclusive splice variants, SNAP-25a and SNAP-25b. To address a potential physiological difference between the two SNAP-25 proteins, we generated gene targeted SNAP-25b deficient mouse mutants by replacing the SNAP-25b specific exon with a second SNAP-25a equivalent. Elimination of SNAP-25b expression resulted in developmental defects, spontaneous seizures, and impaired short-term synaptic plasticity. In adult mutants, morphological changes in hippocampus and drastically altered neuropeptide expression were accompanied by severe impairment of spatial learning. We conclude that the ancient exon duplication in the Snap25 gene provides additional SNAP-25-function required for complex neuronal processes in higher eukaryotes

Note d’accompagnement des tables de correspondances entre les Habitats d’Intérêt Communautaire (HIC) marins et les autres systèmes de classification d’habitats benthiques marins

Ce travail avait pour objectif d’identifier les correspondances possibles entre Habitats d’Intérêt Communautaire (HIC) marins (Tableau 1) et unités d’habitats des typologies nationales (NatHab-Med et NatHab-Atl), typologies EUNIS (EUNIS version 2022) et listes des conventions de mers régionales (OSPAR et Barcelone) en se basant sur la réinterprétation nationale des Habitats d’Intérêt Communautaire (HIC) marins (de Bettignies et al., 2021) et les descriptions des unités d’habitats des typologies nationales (La Rivière et al., 2021 ; 2022). Il constitue une mise à jour du travail d’établissement des correspondances réalisé en 2012 (Michez et al., 2012) en suivant globalement la même méthodologie. Cette note apporte des précisions sur le cadre méthodologique suivi pour établir ces correspondances et sur la structuration des données. Pour chaque HIC, des explications sont données pour assurer une bonne compréhension des correspondances établies, notamment en ce qui concerne les conditions de correspondances résultant du travail de réinterprétation

Note d’accompagnement des tables de correspondances entre les Habitats d’Intérêt Communautaire (HIC) marins et les autres systèmes de classification d’habitats benthiques marins

Ce travail avait pour objectif d’identifier les correspondances possibles entre Habitats d’IntérêtCommunautaire (HIC) marins (Tableau 1) et unités d’habitats des typologies nationales (NatHab-Med et NatHab-Atl), typologies EUNIS (EUNIS version 2022) et listes des conventions de mersrégionales (OSPAR et Barcelone) en se basant sur la réinterprétation nationale des Habitats d’IntérêtCommunautaire (HIC) marins (de Bettignies et al., 2021) et les descriptions des unités d’habitats destypologies nationales (La Rivière et al., 2021 ; 2022). Il constitue une mise à jour du travaild’établissement des correspondances réalisé en 2012 (Michez et al., 2012) en suivantglobalement la même méthodologie.Cette note apporte des précisions sur le cadre méthodologique suivi pour établir cescorrespondances et sur la structuration des données. Pour chaque HIC, des explications sontdonnées pour assurer une bonne compréhension des correspondances établies, notamment en cequi concerne les conditions de correspondances résultant du travail de réinterprétation

Benthic habitats ID and policy cross-links to improve marine conservation

International audienceIdentifying benthic habitat and providing clear definition of management units is central to the effective conservation of the marine environment. After the creation of a French marine habitat classification providing a comprehensive list of benthic habitats possibly occurring in national waters, we described each habitat unit (biocenosis and associated sub-units). At the same time, in order to facilitate the implementation of the Habitat Directive in the marine environment and clearly establish which habitat units should be considered as natural Habitat types of Community Interest (HCI), a national marine HCI definition was specified, as long as correspondences with habitats units of the national typology. These tools based on the best scientific knowledge available allowed to highlight knowledge gaps and will ease the assessment, management and reporting tasks both at local and national scales. By sharing these units' definitions with other Member States, and sharing the outputs of these projects internationally, we hope to facilitate the identification of common benthic habitat units and help to achieve a harmonised interpretation of HCI to be managed in the framework of the Habitat Directive

Benthic habitats ID and policy cross-links to improve marine conservation

International audienceIdentifying benthic habitat and providing clear definition of management units is central to the effective conservation of the marine environment. After the creation of a French marine habitat classification providing a comprehensive list of benthic habitats possibly occurring in national waters, we described each habitat unit (biocenosis and associated sub-units). At the same time, in order to facilitate the implementation of the Habitat Directive in the marine environment and clearly establish which habitat units should be considered as natural Habitat types of Community Interest (HCI), a national marine HCI definition was specified, as long as correspondences with habitats units of the national typology. These tools based on the best scientific knowledge available allowed to highlight knowledge gaps and will ease the assessment, management and reporting tasks both at local and national scales. By sharing these units' definitions with other Member States, and sharing the outputs of these projects internationally, we hope to facilitate the identification of common benthic habitat units and help to achieve a harmonised interpretation of HCI to be managed in the framework of the Habitat Directive