Dissecting the autism-associated 16p11.2 locus identifies multiple drivers in neuroanatomical phenotypes and unveils a male-specific role for the major vault protein

Background Using mouse genetic studies and systematic assessments of brain neuroanatomical phenotypes, we set out to identify which of the 30 genes causes brain defects at the autism-associated 16p11.2 locus. Results We show that multiple genes mapping to this region interact to regulate brain anatomy, with female mice exhibiting far fewer brain neuroanatomical phenotypes. In male mice, among the 13 genes associated with neuroanatomical defects (Mvp, Ppp4c, Zg16, Taok2, Slx1b, Maz, Fam57b, Bola2, Tbx6, Qprt, Spn, Hirip3, and Doc2a), Mvp is the top driver implicated in phenotypes pertaining to brain, cortex, hippocampus, ventricles, and corpus callosum sizes. The major vault protein (MVP), the main component of the vault organelle, is a conserved protein found in eukaryotic cells, yet its function is not understood. Here, we find MVP expression highly specific to the limbic system and show that Mvp regulates neuronal morphology, postnatally and specifically in males. We also recapitulate a previously reported genetic interaction and show that Mvp+/−;Mapk3+/− mice exhibit behavioral deficits, notably decreased anxiety-like traits detected in the elevated plus maze and open field paradigms. Conclusions Our study highlights multiple gene drivers in neuroanatomical phenotypes, interacting with each other through complex relationships. It also provides the first evidence for the involvement of the major vault protein in the regulation of brain size and neuroanatomy, specifically in male mice

Models of <i>KPTN</i>-related disorder implicate mTOR signalling in cognitive and overgrowth phenotypes

KPTN-related disorder is an autosomal recessive disorder associated with germline variants in KPTN (previously known as kaptin), a component of the mTOR regulatory complex KICSTOR. To gain further insights into the pathogenesis of KPTN-related disorder, we analysed mouse knockout and human stem cell KPTN loss-of-function models. Kptn -/- mice display many of the key KPTN-related disorder phenotypes, including brain overgrowth, behavioural abnormalities, and cognitive deficits. By assessment of affected individuals, we have identified widespread cognitive deficits (n = 6) and postnatal onset of brain overgrowth (n = 19). By analysing head size data from their parents (n = 24), we have identified a previously unrecognized KPTN dosage-sensitivity, resulting in increased head circumference in heterozygous carriers of pathogenic KPTN variants. Molecular and structural analysis of Kptn-/- mice revealed pathological changes, including differences in brain size, shape and cell numbers primarily due to abnormal postnatal brain development. Both the mouse and differentiated induced pluripotent stem cell models of the disorder display transcriptional and biochemical evidence for altered mTOR pathway signalling, supporting the role of KPTN in regulating mTORC1. By treatment in our KPTN mouse model, we found that the increased mTOR signalling downstream of KPTN is rapamycin sensitive, highlighting possible therapeutic avenues with currently available mTOR inhibitors. These findings place KPTN-related disorder in the broader group of mTORC1-related disorders affecting brain structure, cognitive function and network integrity.</p

Analyses des causes génétiques du syndrome de micro-délétion du 16p11.2 et de l’impact de la protéine majeure de la voute (MVP) et de son interaction avec MAPK3 dans la physiologie cérébrale

Using mouse genetic studies, we set out to identify which of the 30 genes causes brain size and neuroanatomical phenotypes at the autism-associated 16p11.2 locus. We show that multiple genes mapping to this region interact to regulate brain size in contrast to previous studies, with female mice exhibiting far fewer neuroanatomical phenotypes. The major vault protein (MVP), the main component of the vault organelle, is a highly conserved protein found in eukaryotic cells, yet its function is not understood. Here, we find MVP expression specific to the limbic system and show that Mvp is the top driver of neuroanatomical phenotypes, regulating the morphology of neurons, postnatally and specifically in male. We also demonstrate that the double hemideletion Mvp::Mapk3rescues the brain size phenotype of Mvp-deficient male mice, suggesting that MVP and ERK are involved in the same signalling pathway in vivo with MVP possibly acting as an upstream regulator for ERK signalling controlling brain size. Our results provide the first evidence for the involvement of the vault organelle in the regulation of the mammalian brain size and limbic structures.En utilisant des modèles génétiques murins, nous avons cherché à identifier lequel des 30 gènes du locus 16p11.2, associé à l'autisme, provoque des phénotypes neuroanatomiques. Nous montrons, contrairement aux études précédentes, que plusieurs gènes cartographiés dans cette région interagissent pour réguler la taille du cerveau et que les souris femelles présentent beaucoup moins de phénotypes. La protéine majeure de la voûte (MVP) est une protéine hautement conservée présente dans les cellules eucaryotes dont la fonction n'est toujours pas comprise. Dans cette étude,nous montrons que Mvp est le principal gène responsable des phénotypes neuroanatomiques, et qu’il régule la morphologie des neurones, après la naissance et spécifiquement chez les mâles. Nous démontrons également que la double délétion Mvp::Mapk3 restore le phénotype, suggérant que MVP et ERK sont impliqués dans la même voie de signalisation, par un potentiel rétrocontrôle négatif exercé par MVP sur ERK. Nos résultats fournissent la première preuve de l'implication de la voûte dans la régulation de la taille du cerveau des mammifères et des structures limbiques

Analyses des causes génétiques du syndrome de micro-délétion du 16p11.2 et de l’impact de la protéine majeure de la voute (MVP) et de son interaction avec MAPK3 dans la physiologie cérébrale

En utilisant des modèles génétiques murins, nous avons cherché à identifier lequel des 30 gènes du locus 16p11.2, associé à l'autisme, provoque des phénotypes neuroanatomiques. Nous montrons, contrairement aux études précédentes, que plusieurs gènes cartographiés dans cette région interagissent pour réguler la taille du cerveau et que les souris femelles présentent beaucoup moins de phénotypes. La protéine majeure de la voûte (MVP) est une protéine hautement conservée présente dans les cellules eucaryotes dont la fonction n'est toujours pas comprise. Dans cette étude,nous montrons que Mvp est le principal gène responsable des phénotypes neuroanatomiques, et qu’il régule la morphologie des neurones, après la naissance et spécifiquement chez les mâles. Nous démontrons également que la double délétion Mvp::Mapk3 restore le phénotype, suggérant que MVP et ERK sont impliqués dans la même voie de signalisation, par un potentiel rétrocontrôle négatif exercé par MVP sur ERK. Nos résultats fournissent la première preuve de l'implication de la voûte dans la régulation de la taille du cerveau des mammifères et des structures limbiques.Using mouse genetic studies, we set out to identify which of the 30 genes causes brain size and neuroanatomical phenotypes at the autism-associated 16p11.2 locus. We show that multiple genes mapping to this region interact to regulate brain size in contrast to previous studies, with female mice exhibiting far fewer neuroanatomical phenotypes. The major vault protein (MVP), the main component of the vault organelle, is a highly conserved protein found in eukaryotic cells, yet its function is not understood. Here, we find MVP expression specific to the limbic system and show that Mvp is the top driver of neuroanatomical phenotypes, regulating the morphology of neurons, postnatally and specifically in male. We also demonstrate that the double hemideletion Mvp::Mapk3rescues the brain size phenotype of Mvp-deficient male mice, suggesting that MVP and ERK are involved in the same signalling pathway in vivo with MVP possibly acting as an upstream regulator for ERK signalling controlling brain size. Our results provide the first evidence for the involvement of the vault organelle in the regulation of the mammalian brain size and limbic structures

Analyses des causes génétiques du syndrome de micro-délétion du 16p11.2 et de l’impact de la protéine majeure de la voute (MVP) et de son interaction avec MAPK3 dans la physiologie cérébrale

Using mouse genetic studies, we set out to identify which of the 30 genes causes brain size and neuroanatomical phenotypes at the autism-associated 16p11.2 locus. We show that multiple genes mapping to this region interact to regulate brain size in contrast to previous studies, with female mice exhibiting far fewer neuroanatomical phenotypes. The major vault protein (MVP), the main component of the vault organelle, is a highly conserved protein found in eukaryotic cells, yet its function is not understood. Here, we find MVP expression specific to the limbic system and show that Mvp is the top driver of neuroanatomical phenotypes, regulating the morphology of neurons, postnatally and specifically in male. We also demonstrate that the double hemideletion Mvp::Mapk3rescues the brain size phenotype of Mvp-deficient male mice, suggesting that MVP and ERK are involved in the same signalling pathway in vivo with MVP possibly acting as an upstream regulator for ERK signalling controlling brain size. Our results provide the first evidence for the involvement of the vault organelle in the regulation of the mammalian brain size and limbic structures.En utilisant des modèles génétiques murins, nous avons cherché à identifier lequel des 30 gènes du locus 16p11.2, associé à l'autisme, provoque des phénotypes neuroanatomiques. Nous montrons, contrairement aux études précédentes, que plusieurs gènes cartographiés dans cette région interagissent pour réguler la taille du cerveau et que les souris femelles présentent beaucoup moins de phénotypes. La protéine majeure de la voûte (MVP) est une protéine hautement conservée présente dans les cellules eucaryotes dont la fonction n'est toujours pas comprise. Dans cette étude,nous montrons que Mvp est le principal gène responsable des phénotypes neuroanatomiques, et qu’il régule la morphologie des neurones, après la naissance et spécifiquement chez les mâles. Nous démontrons également que la double délétion Mvp::Mapk3 restore le phénotype, suggérant que MVP et ERK sont impliqués dans la même voie de signalisation, par un potentiel rétrocontrôle négatif exercé par MVP sur ERK. Nos résultats fournissent la première preuve de l'implication de la voûte dans la régulation de la taille du cerveau des mammifères et des structures limbiques

A method for parasagittal sectioning for neuroanatomical quantification of brain structures in the adult mouse

International audienceAbstract In this article, we present a standardized protocol for fast and robust neuroanatomical phenotyping of the adult mouse brain, which complements a previously published article (doi: 10.1002/cpmo.12) in Current Protocols in Mouse Biology. It is aimed at providing an experimental pipeline within an academic research setting from experimental work to data analysis. Our analysis focuses on one single parasagittal plane, covering the majority of brain regions involved in higher order cognitions such as the cortex, hippocampus, and cerebellum, for a total of 166 parameters of area, length, and cell-level measurements in contrast to 78 parameters in our previously published coronal screen. Benefits of using parasagittal analysis for large-scale neuroanatomic screens are discussed

WD40-repeat 47 is essential for brain development via microtubule-mediated processes and autophagy

International audienc

WD40-repeat 47 is essential for brain development via microtubule-mediated processes and autophagy

Erreur dates et n° de conférence dans l'url https://hal.archives-ouvertes.fr/hal-02378786.International audienc

WD40-repeat 47, a microtubule-associated protein, is essential for brain development and autophagy.

The family of WD40-repeat (WDR) proteins is one of the largest in eukaryotes, but little is known about their function in brain development. Among 26 WDR genes assessed, we found 7 displaying a major impact in neuronal morphology when inactivated in mice. Remarkably, all seven genes showed corpus callosum defects, including thicker (Atg16l1, Coro1c, Dmxl2, and Herc1), thinner (Kif21b and Wdr89), or absent corpus callosum (Wdr47), revealing a common role for WDR genes in brain connectivity. We focused on the poorly studied WDR47 protein sharing structural homology with LIS1, which causes lissencephaly. In a dosage-dependent manner, mice lacking Wdr47 showed lethality, extensive fiber defects, microcephaly, thinner cortices, and sensory motor gating abnormalities. We showed that WDR47 shares functional characteristics with LIS1 and participates in key microtubule-mediated processes, including neural stem cell proliferation, radial migration, and growth cone dynamics. In absence of WDR47, the exhaustion of late cortical progenitors and the consequent decrease of neurogenesis together with the impaired survival of late-born neurons are likely yielding to the worsening of the microcephaly phenotype postnatally. Interestingly, the WDR47-specific C-terminal to LisH (CTLH) domain was associated with functions in autophagy described in mammals. Silencing WDR47 in hypothalamic GT1-7 neuronal cells and yeast models independently recapitulated these findings, showing conserved mechanisms. Finally, our data identified superior cervical ganglion-10 (SCG10) as an interacting partner of WDR47. Taken together, these results provide a starting point for studying the implications of WDR proteins in neuronal regulation of microtubules and autophagy

Erratum to: Guidelines for the use and interpretation of assays for monitoring autophagy (3rd edition) (Autophagy, 12, 1, 1-222, 10.1080/15548627.2015.1100356

non present