Project description:Abnormal N-methyl-D-aspartate receptor (NMDAR) function has been implicated in the pathophysiology of schizophrenia. D-serine is an important NMDAR modulator, and to elucidate the role of the D-serine synthesis enzyme serine racemase (Srr) in schizophrenia, we identified and characterized mice with an ENU-induced mutation that results in a complete loss of Srr activity and drastically reduced D-serine levels. Mutant mice displayed behaviors relevant to schizophrenia, including impairments in prepulse inhibition, sociability and spatial discrimination. Behavioral deficits were rescued by D-serine and the atypical antipsychotic clozapine, and were conversely, amplified by NMDAR inhibition. Expression profiling revealed that the Srr mutation influenced several genes that have been linked to schizophrenia and cognitive ability. Furthermore, analysis of Srr genetic variants in humans identified a robust association with schizophrenia. This study demonstrates that aberrant serine racemase function and diminished D-serine may contribute to schizophrenia pathogenesis, and that D-serine may be a beneficial form of treatment Keywords: genetic-mutant vs. wildtype comparison
Project description:Abstract: The imbalance of prenatal micronutrients may perturb one-carbon (C1) metabolism and increase the risk for neuropsychiatric disorders. Prenatal excessive methionine (MET) produces in mice behavioral phenotypes reminiscent of human schizophrenia. Whether in-utero programming or early life caregiving mediate these effects is, however, unknown. Here, we show that the behavioral deficits of MET are independent of the early life mother-infant interaction. We also show that MET produces in early life profound changes in the brain C1 pathway components as well as glutamate transmission, mitochondrial function, and lipid metabolism. Bioinformatics analysis integrating metabolomics and transcriptomic data reveal dysregulations of glutamate transmission and lipid metabolism, and identify perturbed pathways of methylation and redox reactions. Our transcriptomics Linkage analysis of MET mice and schizophrenia subjects reveals master genes involved in inflammation and myelination. Finally, we identify potential metabolites as early biomarkers for neurodevelopmental defects and suggest new therapeutic targets for schizophrenia.
Project description:Setd1a Insufficiency in Mice Attenuates Excitatory Synaptic Function and Recapitulates Schizophrenia-related behavioral abnormalities
Project description:To characterize the genetic basis of hybrid male sterility in detail, we used a systems genetics approach, integrating mapping of gene expression traits with sterility phenotypes and QTL. We measured genome-wide testis expression in 305 male F2s from a cross between wild-derived inbred strains of M. musculus musculus and M. m. domesticus. We identified several thousand cis- and trans-acting QTL contributing to expression variation (eQTL). Many trans eQTL cluster into eleven ‘hotspots,’ seven of which co-localize with QTL for sterility phenotypes identified in the cross. The number and clustering of trans eQTL - but not cis eQTL - were substantially lower when mapping was restricted to a ‘fertile’ subset of mice, providing evidence that trans eQTL hotspots are related to sterility. Functional annotation of transcripts with eQTL provides insights into the biological processes disrupted by sterility loci and guides prioritization of candidate genes. Using a conditional mapping approach, we identified eQTL dependent on interactions between loci, revealing a complex system of epistasis. Our results illuminate established patterns, including the role of the X chromosome in hybrid sterility.
Project description:Schizophrenia (SZ) is a devastating psychiatric illness affecting 1% of the world population. In addition to genetic predisposition, environmental factors contribute to the risk for developing SZ. Such genome environment interactions frequently activate epigenetic and epitranscriptomic mechansims. There are emerging evidence that genetic and environmental risk factors merge at the level of microRNA expression, which are discussed as biomarker and therapeutic target in various disorders including neuropsychiatric diseases. In this study we analyzed the blood microRNAome of healthy individuals and SZ patients via small RNA sequencing. By combining these data with a corresponding analysis of post-mortem human brain tissue, we identify one candidate microRNA that is down-regulated in patients. Moreover, its expression is significantly correlated to disease phenotypes. Manipulation of this microRNAs in mouse prefrontal cortex causes schizophrenia-like phenotypes. Functional analysis revealed the cellular processes affected by this microRNA and allowed us to develop an arsenal of RNA-based therapeutic approaches that are able to ameliorate molecular disease phenotypes in mouse and human-based cellular systems as well as the behavioral phenotypes. In conclusion, we identify a novel microRNA as target for stratified RNA-therapeutics in schizophrenia.
Project description:Chronic opiate use produces molecular and cellular adaptations in the nervous system, leading to tolerance, physical dependence and addiction. Genome-wide comparison of morphine-induced changes in brain transcription of mouse strains with different opioid-related phenotypes provides an opportunity to discover the relationship between gene expression and behavioral response to the drug. Keywords: Drug response
Project description:To characterize the genetic basis of hybrid male sterility in detail, we used a systems genetics approach, integrating mapping of gene expression traits with sterility phenotypes and QTL. We measured genome-wide testis expression in 305 male F2s from a cross between wild-derived inbred strains of M. musculus musculus and M. m. domesticus. We identified several thousand cis- and trans-acting QTL contributing to expression variation (eQTL). Many trans eQTL cluster into eleven M-bM-^@M-^Xhotspots,M-bM-^@M-^Y seven of which co-localize with QTL for sterility phenotypes identified in the cross. The number and clustering of trans eQTL - but not cis eQTL - were substantially lower when mapping was restricted to a M-bM-^@M-^XfertileM-bM-^@M-^Y subset of mice, providing evidence that trans eQTL hotspots are related to sterility. Functional annotation of transcripts with eQTL provides insights into the biological processes disrupted by sterility loci and guides prioritization of candidate genes. Using a conditional mapping approach, we identified eQTL dependent on interactions between loci, revealing a complex system of epistasis. Our results illuminate established patterns, including the role of the X chromosome in hybrid sterility. Gene expression was measured in whole testis in males aged 70(M-BM-15) days. Samples include 294 WSB/EiJ x PWD/PhJ F2s, 11 PWD/PhJ x WSB/EiJ F2s, 8 WSB/EiJ, 8 PWD/PhJ, 6 PWD/PhJ x WSB/EiJ F1s and 4 WSB/EiJ x PWD/PhJ F1s.
Project description:Chronic opiate use produces molecular and cellular adaptations in the nervous system, leading to tolerance, physical dependence and addiction. Genome-wide comparison of morphine-induced changes in brain transcription of mouse strains with different opioid-related phenotypes provides an opportunity to discover the relationship between gene expression and behavioral response to the drug. Experiment Overall Design: Microarray experiment was designed to determine the impact of genetic background on the transcriptional effects of morphine in the striatum. The effects of single (20 mg/kg, s.c.) and repeated morphine administration (10-40 mg/kg, 3 times daily for 5 days) were analyzed in four inbred mouse strains (129P3/J. DBA/2J, C57BL/6J, SWR/J). Twelve experimental groups were compared. Control animals received injections of saline. Three independent biological replicates of the microarray were prepared for each experimental group. For each array, independent pools of total RNA from three animals were prepared.
Project description:Schizophrenia is a complex genetic and developmental disorder. We present a model of disease resulting from disruption of a specific stage of homeostatic scaling (HS). HS modifies synapses and circuits in response to changes in neuronal activity and underlies cortical development and memory consolidation. Neuronal pentraxin 2 (NPTX2) plays a critical role in HS and its homeostatic action requires exocytosis at excitatory synapses on parvalbumin interneurons (PV) whereupon a portion is later shed into the CSF. CSF NPTX2 is reduced in two independent cohorts of patients with schizophrenia. To understand the relationship of this biomarker to disease we confirmed that in normal volunteers CSF NPTX2 increases rapidly with sleep deprivation consistent with behavior-linked exocytosis/shedding. In mouse neocortex NPTX2 exocytosis/shedding are activity-dependent and coupled to circadian behavioral. By contrast, in mouse genetic models that interrupt early events in HS NPTX2 exocytosis/shedding are erratic and not linked to behavior. The vital contribution of NPTX2 to homeostasis is revealed in Nptx2-/- mice, which exhibit sensitivity to social isolation stress and multiple schizophrenia-domain phenotypes. NPTX2 is not implicated by human genome studies; rather we propose that diverse mutations linked to schizophrenia disrupt activity-dependent mechanisms required for NPTX2 function. The ability to monitor NPTX2 in human subjects provides an opportunity to translate fundamental neuroscience to human neuropsychiatric disease.