Biology subjects

Herault, Y.

Publications and source records attributed to Herault, Y..

33 records · Page 2Linked to original sources

bioRxiv2021

The production of 4,182 mouse lines identifies experimental and biological variables impacting Cas9-mediated mutant mouse line production

The International Mouse Phenotyping Consortium (IMPC) systematically produces and phenotypes mouse lines with presumptive null mutations to provide insight into gene function. The IMPC now uses the programmable RNA-guided nuclease Cas9 for its increased capacity and flexibility to efficiently generate null alleles in the C57BL/6N strain. In addition to being a valuable novel and accessible research resource, the production of 3,313 knockout mouse lines using comparable protocols provides a rich dataset to analyze experimental and biological variables affecting in vivo gene engineering with Cas9. Mouse line production has two critical steps - generation of founders with the desired allele and germline transmission (GLT) of that allele from founders to offspring. A systematic evaluation of the variables impacting success rates identified gene essentiality as the primary factor influencing successful production of null alleles. Collectively, our findings provide best practice recommendations for using Cas9 to generate alleles in mouse essential genes, many of which are orthologs of genes linked to human disease.

genetics↗

bioRxiv2021

Isolation, omics characterization and organotypic culture of alveolar type II pulmonary epithelial cells

The alveolar type II (AT2) epithelial cell fraction includes the stem cells of the pulmonary alveoli, functioning in lung homeostasis and post-injury repair. AT2 cells have been characterized primarily in situ, in transgenic mouse models. We report a new methodology for their isolation, their "omics" characterization and stroma-cell-free organotypic culture. Our multi-omics analysis identified high expression of genes involved in oxidative phosphorylation and of AP-1 components, as well as new phosphorylation sites in AT2 biomarkers. Furthermore, we show that supplementation with KGF, FGF10 & HGF suffices for the in vitro proliferation of AT2 cells and formation of alveolar organoids, suggesting that AT2-based organotypic development depends on ligands of the c-Met and FGFR2 receptors. The reported methodology and in-depth molecular characterization provide new tools for the in vitro and in vivo functional analysis of pulmonary cells and of mouse models of lung disease.

cell biology↗

bioRxiv2021

Identifying developing interneurons as a potential target for multiple genetic autism risk factors in human and rodent forebrain.

Autism spectrum condition or autism is associated with numerous monogenic and polygenic genetic risk factors including the polygenic 16p11.2 microdeletion. A central question is what neural cells are affected. To systematically investigate we analysed single cell transcriptomes from gestational week (GW) 8-26 human foetal prefrontal cortex and identified a subset of interneurons (INs) first appearing at GW23 with enriched expression of a disproportionately large fraction of risk factor transcripts. This suggests the hypothesis that these INs are disproportionately vulnerable to mutations causing autism. We investigated this in a rat model of the 16p11.2 microdeletion. We found no change in the numbers or position of either excitatory or inhibitory neurons in the somatosensory cortex or CA1 of 16p11.2+/- rats but found that CA1 Sst INs were hyperexcitable with an enlarged axon initial segment, which was not the case for CA1 pyramidal cells. This study prompts deeper investigation of IN development as a convergent target for autism genetic risk factors.

neuroscience↗

bioRxiv2020

The effects of CSTB duplication on APP/amyloid-β pathology and cathepsin activity in a mouse model

People with Down syndrome (DS), caused by trisomy of chromosome 21 have a greatly increased risk of developing Alzheimers disease (AD). This is in part because of triplication of a chromosome 21 gene, APP. This gene encodes amyloid precursor protein, which is cleaved to form amyloid-{beta} that accumulates in the brains of people who have AD. Recent experimental results demonstrate that a gene or genes on chromosome 21, other than APP, when triplicated significantly accelerate amyloid pathology in a transgenic mouse model of amyloid-{beta} deposition. Multiple lines of evidence indicate that cysteine cathepsin activity influences APP cleavage and amyloid-{beta} accumulation. Located on human chromosome 21 (Hsa21) is an endogenous inhibitor of cathepsin proteases, CYSTATIN B (CSTB) which is proposed to regulate cysteine cathepsin activity in vivo. Here we determined if three copies of the mouse gene Cstb is sufficient to modulate beta amyloid (A{beta}) accumulation and cathepsin activity in a transgenic APP mouse model. Duplication of Cstb resulted in an increase in transcriptional and translational levels of Cstb in the mouse cortex but had no effect on the deposition of insoluble A{beta} plaques or the levels of soluble or insoluble A{beta}42, A{beta}40, or A{beta}38 in 6-month old mice. In addition, the increased CSTB did not alter the activity of cathepsin B enzyme in the cortex of 3-month old mice. These results indicate that the single-gene duplication of Cstb is insufficient to elicit a disease-modifying phenotype in the dupCstb x tgAPP mice, underscoring the complexity of the genetic basis of AD-DS and the importance of multiple gene interactions in disease.

neuroscience↗

bioRxiv2020

Pioglitazone improves deficits of Fmr1-KO mouse model of Fragile X syndrome by interfering with excessive diacylglycerol signaling

Fragile X syndrome (FXS), the leading cause of familial intellectual disability, is an uncured disease caused by the absence or loss of function of the FMRP protein. FMRP is an RNA binding protein that controls the translation of specific proteins in neurons. A main target of FMRP in neurons is diacylglycerol kinase kappa (DGKk) and the loss of FMRP leads to a loss of DGK activity causing a diacylglycerol excess in the brain. Excessive diacylglycerol signaling could be a significant contributor to the pathomechanism of FXS. Here we tested the contribution of DAG-signaling in Fmr1-KO mouse model of FXS and we show that pioglitazone, a widely prescribed drug for type 2 diabetes, has ability to correct excessive DAG signaling in the brain and rescue behavioral alterations of the Fmr1-KO mouse. This study highlights the role of lipid signaling homeostasis in FXS and provides arguments to support the testing of pioglitazone for treatment of FXS.

neuroscience↗

bioRxiv2020

Targeting the RHOA pathway improves learning and memory in Kctd13 and 16p11.2 deletion mouse models.

Gene copy number variants (CNV) have an important role in the appearance of neurodevelopmental disorders. Particularly, the deletion of the 16p11.2 locus is associated with autism spectrum disorder, intellectual disability, and several other features. Earlier studies highlighted the implication of Kctd13 genetic imbalance in the 16p11.2 deletion through the regulation of the RHOA pathway. Here, we target the pathway and rescue the cognitive phenotypes of the 16p11.2 deletion mouse models. We used a chronic administration of fasudil (HA1077), an inhibitor of the Rho-associated protein kinase (ROCK), in mouse models carrying a heterozygous inactivation of Kctd13, or the deletion of the entire 16p11.2 BP4-BP5 region. We focused our attention on the most robust cognitive phenotypes seen in the 16p11.2 models and we showed that a chronic fasudil treatment can restore object recognition memory in both mouse models but does not change other behavioural traits. These findings confirm KCTD13 as one target gene causing cognitive deficits in 16p11.2 deletion patients, and the pertinence of the RHOA pathway as a therapeutic path and reinforce the contribution of other gene(s) involved in cognitive defects found in the 16p11.2 CNV models. HIGHLIGHTS- Kctd13 haploinsufficiency recapitulates most of the behaviour phenotypes found in the 16p11.2 Del/+ models - Fasudil treatment restores Kctd13 and 16p11.2 Del/+ mutant phenotypes in novel location and novel object recognition memory tests - Fasudil treatment restores the RhoA pathway in Kctd13+/- and 16p11.2 Del/+ models

animal behavior and cognition↗

bioRxiv2019

Chr21 protein-protein interactions: enrichment in products involved in intellectual disabilities, autism and Late Onset Alzheimer Disease

Intellectual disability (ID) found in Down syndrome (DS), which is characterized by an extra copy of 234 genes on Chr21 is poorly understood. We first used two DS mouse models that either display an extra copy of the Dyrk1A gene or of the mouse Chr16 syntenic region. Exome sequencing of transcripts deregulated in embryonic hippocampus uncovers enrichment in genes involved in chromatin and synapse respectively. Using large-scale yeast two-hybrid screen (154 distinct screens) of human brain library containing at least 107 independent fragments, we identified 3,636 novel protein-protein interactions with an enrichment of direct interactors of both Chromosome 21(Hsa21) baits and rebounds in ID-related genes. Using proximity ligation assays, we identified that Hsa21-encoded proteins are located at the dendritic spine postsynaptic density in a protein network located at the dendritic spine post synapse. We located Hsa21 DYRK1A and DSCAM that confers a [~] 20-fold increase in Autism Spectrum Disorders (ASDs), in this postsynaptic network. We found that a DSCAM intracellular domain binds either DYRK1A or DLGs that are multimeric scaffolds for the clustering of receptors, ion channels, and associated signaling proteins. The DYRK1A-DSCAM interaction is conserved from drosophila to humans. The identified postsynaptic.network is enriched in ARC-related synaptic plasticity, ASDs and Late-Onset Alzheimer Disease. Altogether, these results emphasize links between DS and brain diseases with complex genetics.

neuroscience↗

bioRxiv2019

Leveraging biobank-scale rare and common variant analyses to identify ASPHD1 as the main driver of reproductive traits in the 16p11.2 locus

Whereas genome-wide association studies (GWAS) allowed identifying thousands of associations between variants and traits, their success rate in pinpointing causal genes has been disproportionately low. Here, we integrate biobank-scale phenotype data from carriers of a rare copy-number variant (CNV), Mendelian randomization and animal modeling to identify causative genes in a GWAS locus for age at menarche (AaM). We show that the dosage of the 16p11.2 BP4-BP5 interval is correlated positively with AaM in the UK and Estonian biobanks and 16p11.2 clinical cohorts, with a directionally consistent trend for pubertal onset in males. These correlations parallel an increase in reproductive tract disorders in both sexes. In support of these observations, 16p11.2 mouse models display perturbed pubertal onset and structurally altered reproductive organs that track with CNV dose. Further, we report a negative correlation between the 16p11.2 dosage and relative hypothalamic volume in both humans and mice, intimating a perturbation in the gonadotropin-releasing hormone (GnRH) axis. Two independent lines of evidence identified candidate causal genes for AaM; Mendelian randomization and agnostic dosage modulation of each 16p11.2 gene in zebrafish gnrh3:egfp models. ASPHD1, expressed predominantly in brain and pituitary gland, emerged as a major phenotype driver; and it is subject to modulation by KCTD13 to exacerbate GnRH neuron phenotype. Together, our data highlight the power of an interdisciplinary approach to elucidate disease etiologies underlying complex traits.

genomics↗

bioRxiv2019

The human-specific BOLA2 duplication modifies iron homeostasis and anemia predisposition in chromosome 16p11.2 autism patients

Human-specific duplications at chromosome 16p11.2 mediate recurrent pathogenic 600 kbp BP4-BP5 copy number variations, one of the most common genetic causes of autism. These copy number polymorphic duplications are under positive selection and include 3-8 copies of BOLA2, a gene involved in the maturation of cytosolic iron-sulfur proteins. To investigate the potential advantage provided by the rapid expansion of BOLA2, we assessed hematological traits and anemia prevalence in 379,385 controls and individuals who have lost or gained copies of BOLA2: 89 chromosome 16p11.2 BP4-BP5 deletion and 56 reciprocal duplication carriers in the UK Biobank. We found that the 16p11.2 deletion is associated with anemia (18/89 carriers, 20%, P=4e-7, OR=5), particularly iron-deficiency anemia. We observed similar enrichments in two clinical 16p11.2 deletion cohorts, with 6/63 (10%) and 7/20 (35%) unrelated individuals with anemia, microcytosis, low serum iron, or low blood hemoglobin. Upon stratification by BOLA2 copy number, we found an association between low BOLA2 dosage and the above phenotypes (8/15 individuals with three copies, 53%, P=1e-4). In parallel, we analyzed hematological traits in mice carrying the 16p11.2 orthologous deletion or duplication, as well as Bola2+/- and Bola2-/- animals. The deletion and Bola2-deficient mice showed early evidence of iron deficiency, including a mild decrease in hemoglobin, lower plasma iron, microcytosis, and an increased red blood cell zinc protoporphyrin to heme ratio. Our results indicate that BOLA2 participates in iron homeostasis in vivo and its expansion has a potential adaptive role in protecting against iron deficiency.

genetics↗

bioRxiv2019

Human and mouse essentiality screens as a resource for disease gene discovery

Although genomic sequencing has been transformative in the study of rare genetic diseases, identifying causal variants remains a considerable challenge that can be addressed in part by new gene-specific knowledge. Here, we integrate measures of how essential a gene is to supporting life, as inferred from the comprehensive viability and phenotyping screens performed on knockout mice by the International Mouse Phenotyping Consortium and from human cell line essentiality screens. We propose a novel, cross-species gene classification across the Full Spectrum of Intolerance to Loss-of-function (FUSIL) and demonstrate that genes in five mutually exclusive FUSIL categories have differing characteristics in the biological processes they regulate, tissue expression levels and human mutation rates. Most notably, Mendelian disease genes, particularly those associated with developmental disorders, are highly overrepresented in the developmental lethal category, representing genes not essential for cell survival but required for organism development. Exploiting this finding, we have screened developmental disorder cases from three independent disease sequencing consortia and identified potentially pathogenic, de novo variants shared in different patients for several developmental lethal genes that have not previously been associated with rare disease. We therefore propose FUSIL as an efficient resource for disease gene discovery.

genomics↗

bioRxiv2019

DYRK1A up-regulation specifically impairs a presynaptic form of long-term potentiation

Chromosome 21 DYRK1A kinase has long been associated with a variety of psychiatric diseases including Down Syndrome. We previously showed that Dyrk1A interacts with SWI/SNF (SWItch/Sucrose Non-Fermentable) nucleosome remodeling complex inducing expression changes of genes encoding key neuronal proteins. However, the functional impact of this kinase at the synapse level remains unclear. We studied a mouse model that incorporated the YAC 152F7 (570 kb) encoding six chromosome 21 genes including DYRK1A. We found that DYRK1A Interacts with the key chromatin remodelers EP300 and CREBBP. Moreover, we observed changes in the transcriptional levels of genes encoding presynaptic proteins involved in glutamate vesicle exocytosis, namely Rims1, Munc13-1, Syn2, Rab3A. This result prompted us to investigate the two main forms of long-term potentiation (LTP) required for learning and memory: the (N-methyl d-aspartate) receptor-dependent postsynaptic form versus the glutamate release-dependent presynaptic form. Interestingly, extracellular electrophysiological recordings in hippocampal slices of the YAC mouse line revealed that only the presynaptic forms of plasticity were impacted, leaving the post-synaptic form of plasticity intact. T o refine our findings, we used a mouse BAC 189N3 (152 kb) line that only triplicate the gene Dyrk1A. Again, we found that this presynaptic form of LTP is also impaired in this mouse line. This result demonstrates that abnormal up-regulation of Dyrk1A alone is sufficient to inhibit specifically the presynaptic forms of LTP. Altogether, our results suggest that impairment of DYRK1A gene dosage may impact memory precision, and therefore reinforce our mechanistic understanding of the cognitive impairment detected in this mouse model.

neuroscience↗

bioRxiv2019

Oligogenic effects of 16p11.2 copy number variation on craniofacial development

A copy number variant (CNV) of 16p11.2, which encompasses 30 genes, is associated with developmental and psychiatric disorders, head size and body mass. The genetic mechanisms that underlie these associations are not understood. To elucidate the effects of genes on development, we exploited the quantitative effects of CNV on craniofacial structure in humans and model organisms. We show that reciprocal deletion and duplication of 16p11.2 have characteristic "mirror" effects on craniofacial features that are conserved in human, rat and mouse. By testing gene dosage effects on the shape of the mandible in zebrafish, we show that the distribution of effects for all individual genes is consistent with that of the CNV, and some combinations have non-additive effects. Our results suggest that, at minimum, one third of genes within the 16p11.2 region influence craniofacial development, and the facial gestalt of each CNV represents a product of 30 dosage effects. HighlightsO_LIReciprocal CNVs of 16p11.2 have mirror effects on craniofacial structure. Copy number is associated with a positive effect on nasal and mandibular regions and a negative effect on frontal regions of the face. C_LIO_LIEffects of CNV on craniofacial development in human are well conserved in rat and mouse models of 16p11.2 deletion and duplication. C_LIO_LI7/30 genes each independently have significant effects on the shape of the mandible in zebrafish; these include SPN, C16orf54, SEZ6L2, ASPHD1, TAOK2, INO80E and FAM57B. Others (MAPK3, MVP, KCTD13) have detectable effects only in combination. C_LIO_LIOverexpression of 30 genes individually showed a distribution of effects that was skewed in the same direction as that of the full duplication, suggesting that specific facial features represent the net of all individual effects combined. C_LI

genetics↗

bioRxiv2018

BIN1 recovers tauopathy-induced long-term memory deficits in mice and interacts with Tau through Thr348 phosphorylation

The bridging integrator 1 gene (BIN1) is a major genetic risk factor for Alzheimers disease (AD). In this report, we investigated how BIN1-dependent pathophysiological processes might be associated with Tau. We first generated a cohort of control and transgenic mice either overexpressing human MAPT (TgMAPT) or both human MAPT and BIN1 (TgMAPT;TgBIN1), which we followed-up from 3 to 15 months. In TgMAPT;TgBIN1 mice short-term memory deficits appeared earlier than in TgMAPT mice; however - unlike TgMAPT mice - TgMAPT;TgBIN1 mice did not exhibit any long-term or spatial memory deficits for at least 15 months. After sacrifice of the cohort at 18 months, immunohistochemistry revealed that BIN1 overexpression prevents both Tau mislocalization and somatic inclusion in the hippocampus, where an increase in BIN1-Tau interaction was also observed. We then sought mechanisms controlling the BIN1-Tau interaction. We developed a high-content screening approach to characterize modulators of the BIN1-Tau interaction in an agnostic way (1,126 compounds targeting multiple pathways), and we identified - among others - an inhibitor of Calcineurin, a Ser/Thr phosphatase. We determined that Calcineurin dephosphorylates BIN1 on a Cyclin-dependent kinase phosphorylation site at T348, promoting the open conformation of the neuronal BIN1 isoform. Phosphorylation of this site increases the availability of the BIN1 SH3 domain for Tau interaction, as demonstrated by nuclear magnetic resonance experiments and in primary neurons. Finally, we observed that the levels of the neuronal BIN1 isoform were decreased in AD brains, whereas phospho-BIN1(T348):BIN1 ratio was increased, suggesting a compensatory mechanism. In conclusion, our data support the idea that BIN1 modulates the AD risk through an intricate regulation of its interaction with Tau. Alteration in BIN1 expression or activity may disrupt this regulatory balance with Tau and have direct effects on learning and memory.

neuroscience↗

bioRxiv2018

BIN1 genetic risk factor for Alzheimer is sufficient to induce early structural tract alterations in entorhinal cortex-dentate gyrus pathway and related hippocampal multi-scale impairments

Genetic factors are known to contribute to Late Onset Alzheimers disease (LOAD) but their contribution to pathophysiology, specially to prodomic phases accessible to therapeutic approaches are far to be understood. To translate genetic risk of Alzheimers disease (AD) into mechanistic insight, we generated transgenic mouse lines that express a [~]195 kbp human BAC that includes only BIN1, a gene associated to LOAD. This model gives a modest BIN1 overexpression, dependent of the number of BAC copies. At 6 months of age, we detected impaired entorhinal cortex (EC)-hippocampal pathways with specific impairments in EC-dentate gyrus synaptic long-term potentiation, dendritic spines of granular cells and recognition episodic memory. Structural changes were quantified using MRI. Their whole-brain functional impact were analyzed using resting state fMRI with a hypoconnectivity centered on entorhinal cortex. These early phenotype defects independent of any changes in A-beta can be instrumental in the search for new AD drug targets.

neuroscience↗

bioRxiv2018

Cbs overdosage is necessary and sufficient to induce cognitive phenotypes in mouse models of Down syndrome and interacts genetically with Dyrk1a

Identifying dosage sensitive genes is a key to understand the mechanisms underlying intellectual disability in Down syndrome (DS). The Dp(17Abcg1-Cbs)1Yah DS mouse model (Dp1Yah) show cognitive phenotype and needs to be investigated to identify the main genetic driver. Here, we report that, in the Dp1Yah mice, 3 copies of the Cystathionine-beta-synthase gene (Cbs) are necessary to observe a deficit in the novel object recognition (NOR) paradigm. Moreover, the overexpression of Cbs alone is sufficient to induce NOR deficit. Accordingly targeting the overexpression of human CBS, specifically in Camk2a-expressing neurons, leads to impaired objects discrimination. Altogether this shows that Cbs overdosage is involved in DS learning and memory phenotypes. In order to go further, we identified compounds that interfere with the phenotypical consequence of CBS overdosage in yeast. Pharmacological intervention in the Tg(CBS) with one selected compound restored memory in the novel object recognition. In addition, using a genetic approach, we demonstrated an epistatic interaction between Cbs and Dyrk1a, another human chromosome 21 gene encoding the dual-specificity tyrosine phosphorylation-regulated kinase 1a and an already known target for DS therapeutic intervention. Further analysis using proteomic approaches highlighted several pathways, including synaptic transmission, cell projection morphogenesis, and actin cytoskeleton, that are affected by DYRK1A and CBS overexpression. Overall we demonstrated that CBS overdosage underpins the DS-related recognition memory deficit and that both CBS and DYRK1A interact to control accurate memory processes in DS. In addition, our study establishes CBS as an intervention point for treating intellectual deficiencies linked to DS.\n\nSIGNIFICANT STATEMENTHere, we investigated a region homologous to Hsa21 and located on mouse chromosome 17. We demonstrated using three independent genetic approaches that the overdosage of the Cystathionine-beta-synthase gene (Cbs) gene, encoded in the segment, is necessary and sufficient to induce deficit in novel object recognition (NR).\n\nIn addition, we identified compounds that interfere with the phenotypical consequence of CBS overdosage in yeast and in mouse transgenic lines. Then we analyzed the relation between Cbs overdosage and the consequence of DYRK1a overexpression, a main driver of another region homologous to Hsa21 and we demonstrated that an epistatic interaction exist between Cbs and Dyrk1a affecting different pathways, including synaptic transmission, cell projection morphogenesis, and actin cytoskeleton.

genetics↗