Project description:Purpose: 5A3+/del mice, which have a heterozygous germ line deletion of a 2-Mb interval of chromosome band 5A3 syntenic to a commonly deleted segment of human 7q22, exhibit hematopoietic stem cell (HSC) abnormalities that may contribute to myelodysplastic syndrome (MDS) pathogenesis. These defects are cell autonomous. The goal of this study is to compare transcriptome profiling (RNA-seq) data obtained from HSC and multipotent progenitors (MPP) isolated from 5A3+/del mice and their wildtype littermates, in order to identify differentially expressed genes and pathways that may contribute to the phenotype. Methods: Total RNA was isolated from CD150hi-HSC, CD150lo-HSC and CD150neg-MPP from wildtype and 5A3+/del mice. 10ng of total RNA was converted into double-stranded cDNA using the Ovation RNA Amplification System V2 (NuGen, CA), and the amplified cDNA products were then used to generate RNA-seq libraries using the TruSeq RNA Sample Preparation Kit v2 reagents (Illumina, CA) with 10 PCR amplification cycles. Library quality and quantity were assessed by the Agilent DNA1000 Chip (Agilent, CA) and qPCR (Kappa Biosystems Inc, MA). 10 pM of each library was sequenced using Illumina SBS chemistry at 2 x 100 bp reads on the HiSeq2000 (Illumina®, CA). The RNA-Seq paired-end reads were mapped to the mouse mm9 genome using an in-house mapping and quality assessment pipeline. The expression of each gene was estimated by the mean coverage of the highest-covered coding exon. Genes with low expression level (<10) across all samples were filtered out, followed by quantile normalization. Differential expression analysis was performed using limma with estimation of false-discovery rate. Gene Set Enrichment Analysis was used to assess pathway enrichment. Results:Transcriptome (RNA-Seq) and Taqman quantitative real-time PCR analyses revealed a ~50% reduction in the expression of multiple genes and of the long intergenic non-coding RNA 503142E22Rik within the 5A3 interval in mutant HSC and MPP. Gene Set Enrichment Analysis (GSEA) of the RNA-Seq data from 5A3+/del HSCs further demonstrated reduced expression of multiple gene sets related to oxidative phosphorylation (OXPHOS) that are similarly down-regulated in the early stages of human therapy-induced MDS and AML. Conclusions: Our study revealed that genes involved in OXPHOS were down-regulated in 5A3+/del HSC, and this finding provided novel insights into the impact of chromosome 7 deletions on the pathogenesis of MDS. Transcriptome profiling (RNA-seq) data of HSC and MPP isolated from 5A3+/del mice and their wildtype littermates were generated by sequencing, in quintuplicate, using Illumina SBS chemistry at 2 x 100 bp reads on the HiSeq2000 (Illumina®, CA)

Project description:Purpose: 5A3+/del mice, which have a heterozygous germ line deletion of a 2-Mb interval of chromosome band 5A3 syntenic to a commonly deleted segment of human 7q22, exhibit hematopoietic stem cell (HSC) abnormalities that may contribute to myelodysplastic syndrome (MDS) pathogenesis. These defects are cell autonomous. The goal of this study is to compare transcriptome profiling (RNA-seq) data obtained from HSC and multipotent progenitors (MPP) isolated from 5A3+/del mice and their wildtype littermates, in order to identify differentially expressed genes and pathways that may contribute to the phenotype. Methods: Total RNA was isolated from CD150hi-HSC, CD150lo-HSC and CD150neg-MPP from wildtype and 5A3+/del mice. 10ng of total RNA was converted into double-stranded cDNA using the Ovation RNA Amplification System V2 (NuGen, CA), and the amplified cDNA products were then used to generate RNA-seq libraries using the TruSeq RNA Sample Preparation Kit v2 reagents (Illumina, CA) with 10 PCR amplification cycles. Library quality and quantity were assessed by the Agilent DNA1000 Chip (Agilent, CA) and qPCR (Kappa Biosystems Inc, MA). 10 pM of each library was sequenced using Illumina SBS chemistry at 2 x 100 bp reads on the HiSeq2000 (Illumina®, CA). The RNA-Seq paired-end reads were mapped to the mouse mm9 genome using an in-house mapping and quality assessment pipeline. The expression of each gene was estimated by the mean coverage of the highest-covered coding exon. Genes with low expression level (<10) across all samples were filtered out, followed by quantile normalization. Differential expression analysis was performed using limma with estimation of false-discovery rate. Gene Set Enrichment Analysis was used to assess pathway enrichment. Results:Transcriptome (RNA-Seq) and Taqman quantitative real-time PCR analyses revealed a ~50% reduction in the expression of multiple genes and of the long intergenic non-coding RNA 503142E22Rik within the 5A3 interval in mutant HSC and MPP. Gene Set Enrichment Analysis (GSEA) of the RNA-Seq data from 5A3+/del HSCs further demonstrated reduced expression of multiple gene sets related to oxidative phosphorylation (OXPHOS) that are similarly down-regulated in the early stages of human therapy-induced MDS and AML. Conclusions: Our study revealed that genes involved in OXPHOS were down-regulated in 5A3+/del HSC, and this finding provided novel insights into the impact of chromosome 7 deletions on the pathogenesis of MDS.

Project description:A small number of rare, recurrent genomic copy number variants (CNVs) are known to substantially increase susceptibility to schizophrenia. As a consequence of the low fecundity in people with schizophrenia and other neurodevelopmental phenotypes to which these CNVs contribute, CNVs with large effects on risk are likely to be rapidly removed from the population by natural selection. Accordingly, such CNVs must frequently occur as recurrent de novo mutations. In a sample of 662 schizophrenia proband-parent trios, we found that rare de novo CNV mutations were significantly more frequent in cases (5.1% all cases, 5.5% family history negative) compared with 2.2% among 2623 controls, confirming the involvement of de novo CNVs in the pathogenesis of schizophrenia. Eight de novo CNVs occurred at four known schizophrenia loci (3q29, 15q11.2, 15q13.3 and 16p11.2). De novo CNVs of known pathogenic significance in other genomic disorders were also observed, including deletion at the TAR (thrombocytopenia absent radius) region on 1q21.1 and duplication at the WBS (Williams-Beuren syndrome) region at 7q11.23. Multiple de novos spanned genes encoding members of the DLG (discs large) family of membrane-associated guanylate kinases (MAGUKs) that are components of the postsynaptic density (PSD). Two de novos also affected EHMT1, a histone methyl transferase known to directly regulate DLG family members. Using a systems biology approach and merging novel CNV and proteomics data sets, systematic analysis of synaptic protein complexes showed that, compared with control CNVs, case de novos were significantly enriched for the PSD proteome (P=1.72 × 10??. This was largely explained by enrichment for members of the N-methyl-D-aspartate receptor (NMDAR) (P=4.24 × 10??) and neuronal activity-regulated cytoskeleton-associated protein (ARC) (P=3.78 × 10??) postsynaptic signalling complexes. In an analysis of 18?492 subjects (7907 cases and 10?585 controls), case CNVs were enriched for members of the NMDAR complex (P=0.0015) but not ARC (P=0.14). Our data indicate that defects in NMDAR postsynaptic signalling and, possibly, ARC complexes, which are known to be important in synaptic plasticity and cognition, play a significant role in the pathogenesis of schizophrenia.

Dataset Information

Integrated genomic analysis implicates haploinsufficiency of multiple chromosome 5q31.2 genes in de novo myelodysplastic syndromes pathogenesis.

Publications

Integrated genomic analysis implicates haploinsufficiency of multiple chromosome 5q31.2 genes in de novo myelodysplastic syndromes pathogenesis.

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