Publications by authors named "Yann Hérault"

134 Publications

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

PLoS One 2021 22;16(7):e0242236. Epub 2021 Jul 22.

UK Dementia Research Institute at UCL, London, United Kingdom.

People with Down syndrome (DS), caused by trisomy of chromosome 21 have a greatly increased risk of developing Alzheimer's 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-β 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-β pathology in a transgenic mouse model of amyloid-β deposition. Multiple lines of evidence indicate that cysteine cathepsin activity influences APP cleavage and amyloid-β 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 amyloid-β 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 amyloid-β plaques or the levels of soluble or insoluble amyloid-β42, amyloid-β40, or amyloid-β38 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 or 6-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.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0242236PLOS
July 2021

Immune Dysregulation and the Increased Risk of Complications and Mortality Following Respiratory Tract Infections in Adults With Down Syndrome.

Front Immunol 2021;12:621440. Epub 2021 Jun 25.

The Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat Gan, Israel.

The risk of severe outcomes following respiratory tract infections is significantly increased in individuals over 60 years, especially in those with chronic medical conditions, i.e., hypertension, diabetes, cardiovascular disease, dementia, chronic respiratory disease, and cancer. Down Syndrome (DS), the most prevalent intellectual disability, is caused by trisomy-21 in ~1:750 live births worldwide. Over the past few decades, a substantial body of evidence has accumulated, pointing at the occurrence of alterations, impairments, and subsequently dysfunction of the various components of the immune system in individuals with DS. This associates with increased vulnerability to respiratory tract infections in this population, such as the influenza virus, respiratory syncytial virus, SARS-CoV-2 (COVID-19), and bacterial pneumonias. To emphasize this link, here we comprehensively review the immunobiology of DS and its contribution to higher susceptibility to severe illness and mortality from respiratory tract infections.
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http://dx.doi.org/10.3389/fimmu.2021.621440DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8267813PMC
June 2021

Pathogenesis of Anorectal Malformations in Retinoic Acid Receptor Knockout Mice Studied by HREM.

Biomedicines 2021 Jun 28;9(7). Epub 2021 Jun 28.

CNRS, INSERM, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), Université de Strasbourg, 1 rue Laurent Fries, 67404 Illkirch Graffenstaden, France.

Anorectal malformations (ARMs) are relatively common congenital abnormalities, but their pathogenesis is poorly understood. Previous gene knockout studies indicated that the signalling pathway mediated by the retinoic acid receptors (RAR) is instrumental to the formation of the anorectal canal and of various urogenital structures. Here, we show that simultaneous ablation of the three RARs in the mouse embryo results in a spectrum of malformations of the pelvic organs in which anorectal and urinary bladder ageneses are consistently associated. We found that these ageneses could be accounted for by defects in the processes of growth and migration of the cloaca, the embryonic structure from which the anorectal canal and urinary bladder originate. We further show that these defects are preceded by a failure of the lateral shift of the umbilical arteries and propose vascular abnormalities as a possible cause of ARM. Through the comparisons of these phenotypes with those of other mutant mice and of human patients, we would like to suggest that morphological data may provide a solid base to test molecular as well as clinical hypotheses.
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http://dx.doi.org/10.3390/biomedicines9070742DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8301324PMC
June 2021

Droplet digital PCR or quantitative PCR for in-depth genomic and functional validation of genetically altered rodents.

Methods 2021 07 8;191:107-119. Epub 2021 Apr 8.

PHENOMIN-Institut Clinique de la Souris, CELPHEDIA, CNRS, INSERM, Université de Strasbourg, Illkirch-Graffenstaden, Strasbourg 67404, France. Electronic address:

Gene targeting and additive (random) transgenesis have proven to be powerful technologies with which to decipher the mammalian genome. With the advent of CRISPR/Cas9 genome editing, the ability to inactivate or modify the function of a gene has become even more accessible. However, the impact of each generated modification may be different from what was initially desired. Minimal validation of mutant alleles from genetically altered (GA) rodents remains essential to guarantee the interpretation of experimental results. The protocol described here combines design strategies for genomic and functional validation of genetically modified alleles with droplet digital PCR (ddPCR) or quantitative PCR (qPCR) for target DNA or mRNA quantification. In-depth analysis of the results obtained with GA models through the analysis of target DNA and mRNA quantification is also provided, to evaluate which pitfalls can be detected using these two methods, and we propose recommendations for the characterization of different type of mutant allele (knock-out, knock-in, conditional knock-out, FLEx, IKMC model or transgenic). Our results also highlight the possibility that mRNA expression of any mutated allele can be different from what might be expected in theory or according to common assumptions. For example, mRNA analyses on knock-out lines showed that nonsense-mediated mRNA decay is generally not achieved with a critical-exon approach. Likewise, comparison of multiple conditional lines crossed with the same CreER deleter showed that the inactivation outcome was very different for each conditional model. DNA quantification by ddPCR of G0 to G2 generations of transgenic rodents generated by pronuclear injection showed an unexpected variability, demonstrating that G1 generation rodents cannot be considered as established lines.
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http://dx.doi.org/10.1016/j.ymeth.2021.04.001DOI Listing
July 2021

Pain behavior in SCN9A (Nav1.7) and SCN10A (Nav1.8) mutant rodent models.

Neurosci Lett 2021 05 26;753:135844. Epub 2021 Mar 26.

Université de Strasbourg, CNRS, INSERM, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC) Translational Medicine and Neurogenetics Department, Illkirch, France.

The two voltage gated sodium channels Nav1.7 and Nav1.8 are expressed in the peripheral nervous system and involved in various pain conditions including inflammatory and neuropathic pain. Rodent models bearing deletions or mutations of the corresponding genes, Scn9a and Scn10a, were created in order to understand the role of these channels in the pathophysiological mechanism underlying pain symptoms. This review summarizes the pain behavior profiles reported in Scn9a and Scn10a rodent models. The complete loss-of-function or knockout (KO) of Scn9a or Scn10a and the conditional KO (cKO) of Scn9a in specific cell populations were shown to decrease sensitivity to various pain stimuli. The Possum mutant mice bearing a dominant hypermorphic mutation in Scn10a revealed higher sensitivity to noxious stimuli. Several gain-of-function mutations were identified in patients with painful small fiber neuropathy. Future knowledge obtained from preclinical models bearing these mutations will allow understanding how these mutations affect pain. In addition, the review gives perspectives for creating models that better mimic patients' pain symptoms in view to developing novel analgesic strategies.
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http://dx.doi.org/10.1016/j.neulet.2021.135844DOI Listing
May 2021

Multi-influential genetic interactions alter behaviour and cognition through six main biological cascades in Down syndrome mouse models.

Hum Mol Genet 2021 May;30(9):771-788

Université de Strasbourg, CNRS, INSERM, Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), department of translational medicine and neurogenetics 1 rue Laurent Fries, 67404 Illkirch Graffenstaden, France.

Down syndrome (DS) is the most common genetic form of intellectual disability caused by the presence of an additional copy of human chromosome 21 (Hsa21). To provide novel insights into genotype-phenotype correlations, we used standardized behavioural tests, magnetic resonance imaging and hippocampal gene expression to screen several DS mouse models for the mouse chromosome 16 region homologous to Hsa21. First, we unravelled several genetic interactions between different regions of chromosome 16 and how they contribute significantly to altering the outcome of the phenotypes in brain cognition, function and structure. Then, in-depth analysis of misregulated expressed genes involved in synaptic dysfunction highlighted six biological cascades centred around DYRK1A, GSK3β, NPY, SNARE, RHOA and NPAS4. Finally, we provide a novel vision of the existing altered gene-gene crosstalk and molecular mechanisms targeting specific hubs in DS models that should become central to better understanding of DS and improving the development of therapies.
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http://dx.doi.org/10.1093/hmg/ddab012DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8161522PMC
May 2021

Specific Susceptibility to COVID-19 in Adults with Down Syndrome.

Neuromolecular Med 2021 Mar 4. Epub 2021 Mar 4.

The Leslie and Susan Gonda Multidisciplinary Brain Research Center, Bar-Ilan University, 5290002, Ramat-Gan, Israel.

The current SARS-CoV-2 outbreak, which causes COVID-19, is particularly devastating for individuals with chronic medical conditions, in particular those with Down Syndrome (DS) who often exhibit a higher prevalence of respiratory tract infections, immune dysregulation and potential complications. The incidence of Alzheimer's disease (AD) is much higher in DS than in the general population, possibly increasing further the risk of COVID-19 infection and its complications. Here we provide a biological overview with regard to specific susceptibility of individuals with DS to SARS-CoV-2 infection as well as data from a recent survey on the prevalence of COVID-19 among them. We see an urgent need to protect people with DS, especially those with AD, from COVID-19 and future pandemics and focus on developing protective measures, which also include interventions by health systems worldwide for reducing the negative social effects of long-term isolation and increased periods of hospitalization.
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http://dx.doi.org/10.1007/s12017-021-08651-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7929736PMC
March 2021

Identifying causative mechanisms linking early-life stress to psycho-cardio-metabolic multi-morbidity: The EarlyCause project.

PLoS One 2021 21;16(1):e0245475. Epub 2021 Jan 21.

Empirica Communication and Technology Research, Bonn, Germany.

Introduction: Depression, cardiovascular diseases and diabetes are among the major non-communicable diseases, leading to significant disability and mortality worldwide. These diseases may share environmental and genetic determinants associated with multimorbid patterns. Stressful early-life events are among the primary factors associated with the development of mental and physical diseases. However, possible causative mechanisms linking early life stress (ELS) with psycho-cardio-metabolic (PCM) multi-morbidity are not well understood. This prevents a full understanding of causal pathways towards the shared risk of these diseases and the development of coordinated preventive and therapeutic interventions.

Methods And Analysis: This paper describes the study protocol for EarlyCause, a large-scale and inter-disciplinary research project funded by the European Union's Horizon 2020 research and innovation programme. The project takes advantage of human longitudinal birth cohort data, animal studies and cellular models to test the hypothesis of shared mechanisms and molecular pathways by which ELS shapes an individual's physical and mental health in adulthood. The study will research in detail how ELS converts into biological signals embedded simultaneously or sequentially in the brain, the cardiovascular and metabolic systems. The research will mainly focus on four biological processes including possible alterations of the epigenome, neuroendocrine system, inflammatome, and the gut microbiome. Life-course models will integrate the role of modifying factors as sex, socioeconomics, and lifestyle with the goal to better identify groups at risk as well as inform promising strategies to reverse the possible mechanisms and/or reduce the impact of ELS on multi-morbidity development in high-risk individuals. These strategies will help better manage the impact of multi-morbidity on human health and the associated risk.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0245475PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7819604PMC
June 2021

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

Mol Autism 2021 01 13;12(1). Epub 2021 Jan 13.

Université de Strasbourg, CNRS, INSERM, Institut de Génétique Biologie Moléculaire et Cellulaire - UMR 7104 - U1258, IGBMC, 1 rue Laurent Fries, 67404, Illkirch Cedex, France.

Background: Gene copy number variants play an important role in the occurrence 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 16p11.2 deletion through the regulation of the RHOA pathway.

Methods: Here, we generated a new mouse model with a small deletion of two key exons in Kctd13. Then, we targeted the RHOA pathway to rescue the cognitive phenotypes of the Kctd13 and 16p11.2 deletion mouse models in a pure genetic background. We used a chronic administration of fasudil (HA1077), an inhibitor of the Rho-associated protein kinase, for six weeks in mouse models carrying a heterozygous inactivation of Kctd13, or the deletion of the entire 16p11.2 BP4-BP5 homologous region.

Results: We found that the small Kctd13 heterozygous deletion induced a cognitive phenotype similar to the whole deletion of the 16p11.2 homologous region, in the Del/+ mice. We then showed that chronic fasudil treatment can restore object recognition memory in adult heterozygous mutant mice for Kctd13 and for 16p11.2 deletion. In addition, learning and memory improvement occurred in parallel to change in the RHOA pathway.

Limitations: The Kcdt13 mutant line does not recapitulate all the phenotypes found in the 16p11.2 Del/+ model. In particular, the locomotor activity was not altered at 12 and 18 weeks of age and the object location memory was not defective in 18-week old mutants. Similarly, the increase in locomotor activity was not modified by the treatment in the 16p11.2 Del/+ mouse model, suggesting that other loci were involved in such defects. Rescue was observed only after four weeks of treatment but no long-term experiment has been carried out so far. Finally, we did not check the social behaviour, which requires working in another hybrid genetic background.

Conclusion: These findings confirm KCTD13 as one target gene causing cognitive deficits in 16p11.2 deletion patients, and the relevance of the RHOA pathway as a therapeutic path for 16p11.2 deletion. In addition, they reinforce the contribution of other gene(s) involved in cognitive defects found in the 16p11.2 models in older mice.
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http://dx.doi.org/10.1186/s13229-020-00405-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7805198PMC
January 2021

Mouse mutant phenotyping at scale reveals novel genes controlling bone mineral density.

PLoS Genet 2020 12 28;16(12):e1009190. Epub 2020 Dec 28.

Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America.

The genetic landscape of diseases associated with changes in bone mineral density (BMD), such as osteoporosis, is only partially understood. Here, we explored data from 3,823 mutant mouse strains for BMD, a measure that is frequently altered in a range of bone pathologies, including osteoporosis. A total of 200 genes were found to significantly affect BMD. This pool of BMD genes comprised 141 genes with previously unknown functions in bone biology and was complementary to pools derived from recent human studies. Nineteen of the 141 genes also caused skeletal abnormalities. Examination of the BMD genes in osteoclasts and osteoblasts underscored BMD pathways, including vesicle transport, in these cells and together with in silico bone turnover studies resulted in the prioritization of candidate genes for further investigation. Overall, the results add novel pathophysiological and molecular insight into bone health and disease.
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http://dx.doi.org/10.1371/journal.pgen.1009190DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7822523PMC
December 2020

Mechanism of cystathionine-β-synthase inhibition by disulfiram: The role of bis(N,N-diethyldithiocarbamate)-copper(II).

Biochem Pharmacol 2020 12 7;182:114267. Epub 2020 Oct 7.

Chair of Pharmacology, Department of Science and Medicine, University of Fribourg, Fribourg, Switzerland. Electronic address:

Background: Hydrogen sulfide (HS) is an endogenous mammalian gasotransmitter. Cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE) and 3-mercaptopyruvate sulfurtransferase (3-MST) are the principal enzymes responsible for its biogenesis. A recent yeast screen suggested that disulfiram (a well-known inhibitor of aldehyde dehydrogenase and a clinically used drug in the treatment of alcoholism) may inhibit CBS in a cell-based environment. However, prior studies have not observed any direct inhibition of CBS by disulfiram. We investigated the potential role of bioconversion of disulfiram to bis(N,N-diethyldithiocarbamate)-copper(II) complex (CuDDC) in the inhibitory effect of disulfiram on HS production and assessed its effect in two human cell types with high CBS expression: HCT116 colon cancer cells and Down syndrome (DS) fibroblasts.

Methods: HS production from recombinant human CBS, CSE and 3-MST was measured using the fluorescent HS probe AzMC. Mouse liver homogenate (a rich source of CBS) was also employed to measure HS biosynthesis. The interaction of copper with accessible protein cysteine residues was evaluated using the DTNB method. Cell proliferation and viability were measured using the BrdU and MTT methods. Cellular bioenergetics was evaluated by Extracellular Flux Analysis.

Results: While disulfiram did not exert any significant direct inhibitory effect on any of the HS-producing enzymes, its metabolite, CuDDC was a potent inhibitor of CBS and CSE. The mode of its action is likely related to the complexed copper molecule. In cell-based systems, the effects of disulfiram were variable. In colon cancer cells, no significant effect of disulfiram was observed on HS production or proliferation or viability. In contrast, in DS fibroblasts, disulfiram inhibited HS production and improved proliferation and viability. Copper, on its own, failed to have any effects on either cell type, likely due to its low cell penetration. CuDDC inhibited HS production in both cell types studied and exerted the functional effects that would be expected from a CBS inhibitor: inhibition of cell proliferation of cancer cells and a bell-shaped effect (stimulation of proliferation at low concentration and inhibition of these responses at higher concentration) in DS cells. Control experiments using a chemical HS donor showed that, in addition to inhibiting CBS and CSE, part of the biological effects of CuDDC relates to a direct reaction with HS, which occurs through its complexed copper.

Conclusions: Disulfiram, via its metabolite CuDDC acts as an inhibitor of CBS and a scavenger of HS, which, in turn, potently suppresses HS levels in various cell types. Inhibition of HS biosynthesis may explain some of the previously reported actions of disulfiram and CuDDC in vitro and in vivo. Disulfiram or CuDDC may be considered as potential agents for the experimental therapy of various pathophysiological conditions associated with HS overproduction.
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http://dx.doi.org/10.1016/j.bcp.2020.114267DOI Listing
December 2020

Reliable and robust droplet digital PCR (ddPCR) and RT-ddPCR protocols for mouse studies.

Methods 2021 07 25;191:95-106. Epub 2020 Jul 25.

PHENOMIN-Institut Clinique de la Souris, CELPHEDIA, CNRS, INSERM, Université de Strasbourg, Illkirch-Graffenstaden, Strasbourg 67404, France. Electronic address:

Droplet digital PCR (ddPCR) is a recent method developed for the quantification of nucleic acids sequences. It is an evolution of PCR methodology incorporating two principal differences: a PCR reaction is performed in thousands of water-oil emulsion droplets and fluorescence is measured at the end of PCR amplification. It leads to the precise and reproducible quantification of DNA and RNA sequences. Here, we present quantitative methods for DNA and RNA analysis using Bio-Rad QX100 or QX200 systems, respectively. The aim of these methods is to provide useful molecular tools for validating genetically altered animal models such as those subject to CRISPR/Cas9 genome editing, as well for expression or CNV studies. A standard procedure for simultaneous DNA and RNA extraction adapted for mouse organs is also described. These methods were initially designed for mouse studies but also work for samples from other species like rat or human. In our lab, thousands of samples and hundreds of target genes from genetically altered lines were examined using these methods. This large dataset was analyzed to evaluate technical optimizations and limitations. Finally, we propose additional recommendations to be included in dMIQE (Minimum information for publication of quantitative digital PCR experiments) guidelines when using ddPCR instruments.
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http://dx.doi.org/10.1016/j.ymeth.2020.07.004DOI Listing
July 2021

Introduction to Mammalian Genome Special Issue: Epigenetics.

Mamm Genome 2020 06;31(5-6):117-118

Institute of Experimental Genetics, Helmholtz Zentrum München GmbH, Neuherberg, Germany.

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http://dx.doi.org/10.1007/s00335-020-09843-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7368862PMC
June 2020

BAHD1 haploinsufficiency results in anxiety-like phenotypes in male mice.

PLoS One 2020 14;15(5):e0232789. Epub 2020 May 14.

Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute, Jouy-en-Josas, France.

BAHD1 is a heterochomatinization factor recently described as a component of a multiprotein complex associated with histone deacetylases HDAC1/2. The physiological and patho-physiological functions of BAHD1 are not yet well characterized. Here, we examined the consequences of BAHD1 deficiency in the brains of male mice. While Bahd1 knockout mice had no detectable defects in brain anatomy, RNA sequencing profiling revealed about 2500 deregulated genes in Bahd1-/- brains compared to Bahd1+/+ brains. A majority of these genes were involved in nervous system development and function, behavior, metabolism and immunity. Exploration of the Allen Brain Atlas and Dropviz databases, assessing gene expression in the brain, revealed that expression of the Bahd1 gene was limited to a few territories and cell subtypes, particularly in the hippocampal formation, the isocortex and the olfactory regions. The effect of partial BAHD1 deficiency on behavior was then evaluated on Bahd1 heterozygous male mice, which have no lethal or metabolic phenotypes. Bahd1+/- mice showed anxiety-like behavior and reduced prepulse inhibition (PPI) of the startle response. Altogether, these results suggest that BAHD1 plays a role in chromatin-dependent gene regulation in a subset of brain cells and support recent evidence linking genetic alteration of BAHD1 to psychiatric disorders in a human patient.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0232789PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7224496PMC
July 2020

Variability in Genome Editing Outcomes: Challenges for Research Reproducibility and Clinical Safety.

Mol Ther 2020 06 20;28(6):1422-1431. Epub 2020 Mar 20.

Université de Strasbourg, CNRS, INSERM, IGBMC, PHENOMIN-Institut Clinique de la Souris, Celphedia, Strasbourg 67404, France. Electronic address:

Genome editing tools have already revolutionized biomedical research and are also expected to have an important impact in the clinic. However, their extensive use in research has revealed much unpredictability, both off and on target, in the outcome of their application. We discuss the challenges associated with this unpredictability, both for research and in the clinic. For the former, an extensive validation of the model is essential. For the latter, potential unpredicted activity does not preclude the use of these tools but requires that molecular evidence to underpin the relevant risk:benefit evaluation is available. Safe and successful clinical application will also depend on the mode of delivery and the cellular context.
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http://dx.doi.org/10.1016/j.ymthe.2020.03.015DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7264426PMC
June 2020

PATHBIO: an international training program for precision mouse phenotyping.

Mamm Genome 2020 02 22;31(1-2):49-53. Epub 2020 Feb 22.

The Jackson Laboratory, Bar Harbor, ME, USA.

Design and production of genetically engineered mouse strains by individual research laboratories, research teams, large-scale consortia, and the biopharmaceutical industry have magnified the need for qualified personnel to identify, annotate, and validate (phenotype) these potentially new mouse models of human disease. The PATHBIO project has been recently established and funded by the European Union's ERASMUS+ Knowledge Alliance program to address the current shortfall in formally trained personnel. A series of teaching workshops will be given by experts on anatomy, histology, embryology, imaging, and comparative pathology to increase the availability of individuals with formal training to contribute to this important niche of Europe's biomedical research enterprise. These didactic and hands-on workshops are organized into three modules: (1) embryology, anatomy, histology, and the anatomical basis of imaging, (2) image-based phenotyping, and (3) pathology. The workshops are open to all levels of participants from recent graduates to Ph.D., M.D., and veterinary scientists. Participation is available on a competitive basis at no cost for attending. The first series of Workshop Modules was held in 2019 and these will continue for the next 2 years.
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http://dx.doi.org/10.1007/s00335-020-09829-1DOI Listing
February 2020

Preface.

Prog Brain Res 2020 ;251:xv

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http://dx.doi.org/10.1016/S0079-6123(20)30015-7DOI Listing
December 2020

Modeling Down syndrome in animals from the early stage to the 4.0 models and next.

Prog Brain Res 2020 22;251:91-143. Epub 2019 Oct 22.

Université de Strasbourg, CNRS, INSERM, Institut de Génétique et de Biologie Moléculaire et Cellulaire, Illkirch, France; Université de Strasbourg, CNRS, INSERM, PHENOMIN Institut Clinique de la Souris, Illkirch, France. Electronic address:

The genotype-phenotype relationship and the physiopathology of Down Syndrome (DS) have been explored in the last 20 years with more and more relevant mouse models. From the early age of transgenesis to the new CRISPR/CAS9-derived chromosomal engineering and the transchromosomic technologies, mouse models have been key to identify homologous genes or entire regions homologous to the human chromosome 21 that are necessary or sufficient to induce DS features, to investigate the complexity of the genetic interactions that are involved in DS and to explore therapeutic strategies. In this review we report the new developments made, how genomic data and new genetic tools have deeply changed our way of making models, extended our panel of animal models, and increased our understanding of the neurobiology of the disease. But even if we have made an incredible progress which promises to make DS a curable condition, we are facing new research challenges to nurture our knowledge of DS pathophysiology as a neurodevelopmental disorder with many comorbidities during ageing.
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http://dx.doi.org/10.1016/bs.pbr.2019.08.001DOI Listing
December 2020

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

Nat Commun 2020 01 31;11(1):655. Epub 2020 Jan 31.

Institute of Developmental Genetics, Helmholtz Zentrum München, German Research Center for Environmental Health GmbH, 85764, Neuherberg, Germany.

The identification of causal variants in sequencing studies remains a considerable challenge that can be partially addressed by new gene-specific knowledge. Here, we integrate measures of how essential a gene is to supporting life, as inferred from viability and phenotyping screens performed on knockout mice by the International Mouse Phenotyping Consortium and essentiality screens carried out on human cell lines. We propose a 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 biological properties. Most notably, Mendelian disease genes, particularly those associated with developmental disorders, are highly overrepresented among genes non-essential for cell survival but required for organism development. After screening developmental disorder cases from three independent disease sequencing consortia, we identify potentially pathogenic variants in genes not previously associated with rare diseases. We therefore propose FUSIL as an efficient approach for disease gene discovery.
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http://dx.doi.org/10.1038/s41467-020-14284-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6994715PMC
January 2020

A Small Compound Targeting Prohibitin with Potential Interest for Cognitive Deficit Rescue in Aging mice and Tau Pathology Treatment.

Sci Rep 2020 01 24;10(1):1143. Epub 2020 Jan 24.

Service de Pharmacologie et d'Immunoanalyse, CEA, Université Paris-Saclay, F-91191, Gif-sur Yvette, France.

Neurodegenerative diseases, including Alzheimer's and Parkinson's disease, are characterized by increased protein aggregation in the brain, progressive neuronal loss, increased inflammation, and neurogenesis impairment. We analyzed the effects of a new purine derivative drug, PDD005, in attenuating mechanisms involved in the pathogenesis of neurodegenerative diseases, using both in vivo and in vitro models. We show that PDD005 is distributed to the brain and can rescue cognitive deficits associated with aging in mice. Treatment with PDD005 prevents impairment of neurogenesis by increasing sex-determining region Y-box 2, nestin, and also enhances synaptic function through upregulation of synaptophysin and postsynaptic density protein 95. PDD005 treatment also reduced neuro-inflammation by decreasing interleukin-1β expression, activation of astrocytes, and microglia. We identified prohibitin as a potential target in mediating the therapeutic effects of PDD005 for the treatment of cognitive deficit in aging mice. Additionally, in the current study, glycogen synthase kinase appears to attenuate tau pathology.
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http://dx.doi.org/10.1038/s41598-020-57560-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6981120PMC
January 2020

High-throughput discovery of genetic determinants of circadian misalignment.

PLoS Genet 2020 01 13;16(1):e1008577. Epub 2020 Jan 13.

SKL of Pharmaceutical Biotechnology and Model Animal Research Center, Collaborative Innovation Center for Genetics and Development, Nanjing Biomedical Research Institute, Nanjing University, Nanjing, China.

Circadian systems provide a fitness advantage to organisms by allowing them to adapt to daily changes of environmental cues, such as light/dark cycles. The molecular mechanism underlying the circadian clock has been well characterized. However, how internal circadian clocks are entrained with regular daily light/dark cycles remains unclear. By collecting and analyzing indirect calorimetry (IC) data from more than 2000 wild-type mice available from the International Mouse Phenotyping Consortium (IMPC), we show that the onset time and peak phase of activity and food intake rhythms are reliable parameters for screening defects of circadian misalignment. We developed a machine learning algorithm to quantify these two parameters in our misalignment screen (SyncScreener) with existing datasets and used it to screen 750 mutant mouse lines from five IMPC phenotyping centres. Mutants of five genes (Slc7a11, Rhbdl1, Spop, Ctc1 and Oxtr) were found to be associated with altered patterns of activity or food intake. By further studying the Slc7a11tm1a/tm1a mice, we confirmed its advanced activity phase phenotype in response to a simulated jetlag and skeleton photoperiod stimuli. Disruption of Slc7a11 affected the intercellular communication in the suprachiasmatic nucleus, suggesting a defect in synchronization of clock neurons. Our study has established a systematic phenotype analysis approach that can be used to uncover the mechanism of circadian entrainment in mice.
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http://dx.doi.org/10.1371/journal.pgen.1008577DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6980734PMC
January 2020

Optimizing PCR for Mouse Genotyping: Recommendations for Reliable, Rapid, Cost Effective, Robust and Adaptable to High-Throughput Genotyping Protocol for Any Type of Mutation.

Curr Protoc Mouse Biol 2019 Dec;9(4):e65

Institut Clinique de la Souris, PHENOMIN-ICS, Illkirch, France.

Genotyping consists of searching for a DNA sequence variation localized at a well-defined locus in the genome. It is an essential step in animal research because it allows the identification of animals that will be bred to generate and maintain a colony, euthanized to control the available space in the animal facility, or used in experiment protocols. Here we describe polymerase chain reaction (PCR) genotyping protocols for fast, sensitive, easy, and cost-effective characterization of mouse genotype. We discuss optimization of parameters to improve the reliability of each assay and propose recommendations for enhancing reproducibility and reducing the occurrence of inconclusive genotyping. All steps required for efficient genotyping are presented: tissue collection; sample verification and direct DNA lysis; establishment of a robust genotyping strategy with reliable, rapid, and cost-effective assays; and finally, transition to high-throughput automatized PCR, including mix miniaturization and automation. © 2019 The Authors. Basic Protocol 1: Tissue sampling methods and procedure Basic Protocol 2: Sample verification and DNA lysis Basic Protocol 3: Design of a genotyping strategy Basic Protocol 4: Moving to high-throughput genotyping.
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http://dx.doi.org/10.1002/cpmo.65DOI Listing
December 2019

The Human-Specific BOLA2 Duplication Modifies Iron Homeostasis and Anemia Predisposition in Chromosome 16p11.2 Autism Individuals.

Am J Hum Genet 2019 11 24;105(5):947-958. Epub 2019 Oct 24.

Center for Integrative Genomics, University of Lausanne, Lausanne, 1015, Switzerland.

Human-specific duplications at chromosome 16p11.2 mediate recurrent pathogenic 600 kbp BP4-BP5 copy-number variations, which are among the most common genetic causes of autism. These copy-number polymorphic duplications are under positive selection and include three to eight 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 carriers 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, which included 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, our data showed 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 Bola2-deficient mice and the mice carrying the deletion 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.
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http://dx.doi.org/10.1016/j.ajhg.2019.09.023DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6849090PMC
November 2019

Long-lasting correction of in vivo LTP and cognitive deficits of mice modelling Down syndrome with an α5-selective GABA inverse agonist.

Br J Pharmacol 2020 03 9;177(5):1106-1118. Epub 2020 Jan 9.

Institut du Cerveau et de la Moelle épinière, Hôpital de la Pitié-Salpêtrière, Paris, France.

Background And Purpose: Excessive GABAergic inhibition contributes to cognitive dysfunctions in Down syndrome (DS). Selective negative allosteric modulators (NAMs) of α5-containing GABA receptors such as the α5 inverse agonist (α5IA) restore learning and memory deficits in Ts65Dn mice, a model of DS. In this study we have assessed the long-lasting effects of α5IA on in vivo LTP and behaviour in Ts65Dn mice.

Experimental Approach: We made in vivo LTP recordings for six consecutive days in freely moving Ts65Dn mice and their wild-type littermates, treated with vehicle or α5IA. In parallel, Ts65Dn mice were assessed by various learning and memory tests (Y maze, Morris water maze, or the novel object recognition) for up to 7 days, following one single injection of α5IA or vehicle.

Key Results: LTP was not evoked in vivo in Ts65Dn mice at hippocampal CA3-CA1 synapses. However, this deficit was sustainably reversed for at least six consecutive days following a single injection of α5IA. This long-lasting effect of α5IA was also observed when assessing working and long-term memory deficits in Ts65Dn mice.

Conclusion And Implications: We show for the first time in vivo LTP deficits in Ts65Dn mice. These deficits were restored for at least 6 days following acute treatment with α5IA and might be the substrate for the long-lasting pharmacological effects of α5IA on spatial working and long-term recognition and spatial memory tasks. Our results demonstrate the relevance of negative allosteric modulators of α5-containing GABA receptors to the treatment of cognitive deficits associated with DS.
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http://dx.doi.org/10.1111/bph.14903DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7042104PMC
March 2020

Soft windowing application to improve analysis of high-throughput phenotyping data.

Bioinformatics 2020 03;36(5):1492-1500

Korea Mouse Phenotyping Center (KMPC), Korea.

Motivation: High-throughput phenomic projects generate complex data from small treatment and large control groups that increase the power of the analyses but introduce variation over time. A method is needed to utlize a set of temporally local controls that maximizes analytic power while minimizing noise from unspecified environmental factors.

Results: Here we introduce 'soft windowing', a methodological approach that selects a window of time that includes the most appropriate controls for analysis. Using phenotype data from the International Mouse Phenotyping Consortium (IMPC), adaptive windows were applied such that control data collected proximally to mutants were assigned the maximal weight, while data collected earlier or later had less weight. We applied this method to IMPC data and compared the results with those obtained from a standard non-windowed approach. Validation was performed using a resampling approach in which we demonstrate a 10% reduction of false positives from 2.5 million analyses. We applied the method to our production analysis pipeline that establishes genotype-phenotype associations by comparing mutant versus control data. We report an increase of 30% in significant P-values, as well as linkage to 106 versus 99 disease models via phenotype overlap with the soft-windowed and non-windowed approaches, respectively, from a set of 2082 mutant mouse lines. Our method is generalizable and can benefit large-scale human phenomic projects such as the UK Biobank and the All of Us resources.

Availability And Implementation: The method is freely available in the R package SmoothWin, available on CRAN http://CRAN.R-project.org/package=SmoothWin.

Supplementary Information: Supplementary data are available at Bioinformatics online.
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http://dx.doi.org/10.1093/bioinformatics/btz744DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7115897PMC
March 2020

Oligogenic Effects of 16p11.2 Copy-Number Variation on Craniofacial Development.

Cell Rep 2019 09;28(13):3320-3328.e4

Department of Psychiatry, University of California, San Diego, La Jolla, CA 92093, USA; Beyster Center for Genomics of Psychiatric Diseases, University of California, San Diego, La Jolla, CA 92093, USA; Institute for Genomic Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla, CA 92093, USA; Department of Pediatrics, University of California, San Diego, La Jolla, CA 92093, USA. Electronic address:

A copy-number variant (CNV) of 16p11.2 encompassing 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 determine the influence of 16p11.2 genes on development, we investigated the effects of CNV on craniofacial structure in humans and model organisms. We show that deletion and duplication of 16p11.2 have "mirror" effects on specific craniofacial features that are conserved between human and rodent models of the CNV. By testing dosage effects of individual genes on the shape of the mandible in zebrafish, we identify seven genes with significant effects individually and find evidence for others when genes were tested in combination. The craniofacial phenotypes of 16p11.2 CNVs represent a model for studying the effects of genes on development, and our results suggest that the associated facial gestalts are attributable to the combined effects of multiple genes.
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http://dx.doi.org/10.1016/j.celrep.2019.08.071DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6988705PMC
September 2019
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