Project description:Purpose: This study aims to identify the differentially expressed genes in embryonic cardiomyocytes following the knockdown of DNMT3a or DNMT3b expression. Methods: Primary cardiomyocytes were isolated from mouse embryonic day (E) 13.5 ventricles, and cultured for 48 h at 37°C to reach 70-80% confluency. Cells were transfected with either Qiagen FlexiTube GeneSolution (with 4 siRNAs) DNMT3a siRNA (#GS13435), DNMT3b siRNAs (#GS13436), or AllStars negative control siRNA (#1027281) at 0.012 pmol using lipofectamine RNAiMAX (n=3 per treatment). At 72 h after transfection, cells were released with Accutase (Innovative Cell Technologies, San Diego, CA) and dissociated with Accumax (Innovative Cell Technologies). To sort cardiomyocytes, dissociated cells were stained with anti-VCAM1 antibody conjugated with allophycocyanin (APC; BioLegend, San Diego, CA) and magnetically sorted using anti-APC microbeads and magnetic assisted cell sorting (MACS) columns (Miltenyi Biotec, Bergisch Gladbach, Germany). Total RNA was isolated from the sorted cardiomyocytes with the RNAqueous®-Micro Total RNA Isolation Kit (Thermo Fisher Scientific, Waltham, MA). RNA-Seq libraries were prepared with the NEBNext® mRNA Library Prep Master Mix Set for Illumina and NEBNext Multiplex Oligos for Illumina (NEB, Ipswich, MA). The nine Illumina-adapted libraries were pooled at equal molar ratio and sequenced with one High Output 1x75 cycles run on a NextSeq500 sequencer (Illumina). The fastq files generated from RNA-Seq were uploaded to the UF Research Computing Galaxy instance developed by the University of Florida. The data were cleaned with the following steps: removed sequencing artifacts, trimmed 5’ or 3’ ends with low scores, removed adaptor contamination, and filtered low quality reads by the FastQC program. The remaining high quality RNA-Seq reads were mapped to the mouse genome (mm10) with the Tophat2 tool. Counting of RNA-seq reads were performed with HTSeq. Differential expression (DE) of genes between treatments was analyzed using two methods: R packages EdgeR and DEseq2, with Ensembl Mus_GRCm38.79.gtf as the reference annotation. Genes with false discovery rate (FDR) less than 0.05 and absolute fold change greater than 1.5 were considered as significant. Unique DE genes were identified by combining the results generated from the two analytical methods. Results: DE analysis by DEseq2 and EdgeR software revealed that 524 genes were up-regulated, and 586 genes were down-regulated after knockdown of DNMT3a expression for 72 h. With the same analytical methods and criteria, the results of DE analysis showed that the knockdown of DNMT3b increased the expression of 655 genes and decreased the expression of 378 genes.

Project description:Purpose: This study aims to identify the differentially methylated regions in target genes in embryonic cardiomyocytes following the knockdown of DNMT3a or DNMT3b expression. Methods: Primary cardiomyocytes were isolated from mouse embryonic day (E) 13.5 ventricles, and cultured for 48 h at 37°C to reach 70-80% confluency. Cells were transfected with either Qiagen FlexiTube GeneSolution (with 4 siRNAs) DNMT3a siRNA (#GS13435), DNMT3b siRNAs (#GS13436), or AllStars negative control siRNA (#1027281) at 0.012 pmol using lipofectamine RNAiMAX (n=3 per treatment). At 72 h after transfection, cells were released with Accutase (Innovative Cell Technologies, San Diego, CA) and dissociated with Accumax (Innovative Cell Technologies). To sort cardiomyocytes, dissociated cells were stained with anti-VCAM1 antibody conjugated with allophycocyanin (APC; BioLegend, San Diego, CA) and magnetically sorted using anti-APC microbeads and magnetic assisted cell sorting (MACS) columns (Miltenyi Biotec, Bergisch Gladbach, Germany). DNA was extracted with the Quick-gDNA™ MicroPrep kit (Zymo Research, Irvine, CA). Genomic DNA was treated with sodium metabisulfite for bisulfite conversion. Target gene regions for fifteen target genes (two promoter regions per gene) were PCR-amplified from the bisulfite-converted DNA with ZymoTaq™ PreMix (Hot start DNA taq polymerase, ZYMO Research, Irvine, CA). The fifteen genes include Myh6, Myh7, Myh7b, Nppa, Nppb, Tnnc1, Tnni3, Tnnt2, Camta1, Camta2, Cdkn1A, Cdkn1B, Cdkn1C, Mef2c, and Mef2d. PCR products were cleaned with the ZR-96 DNA Clean & Concentrator™-5 kit (ZYMO Research). PCR products from the same genomic DNA sample were pooled at equal concentration ratio and made into an indexed sequencing library with the Nextera XT DNA Library Preparation kit and the Nextera XT Index Kit (Illumina, San Diego, CA). The nine Illumina-adapted libraries were pooled at equal molar ratio, spiked with 20% PhiX control libraries (Illumina), and sequenced with one 1x150 cycles run (v3) on a MiSeq sequencer (Illumina). The fastq files generated from MiSeq were uploaded to the UF Research Computing Galaxy instance developed by the University of Florida. The data were cleaned with the following steps: removed sequencing artifacts, trimmed 5’ or 3’ ends with low scores, removed adaptor contamination, and filtered low quality reads by the FastQC program. A reference genome with the amplicon sequences was built and bisulfite converted in silico with Bismark Bisulfite Mapper. The high quality sequence reads were aligned to the reference genome using Bowtie 2. Cytosine methylation counting was performed with the Bismark methylation extractor. Differential methylation was analyzed with the Methylkit package. CpG sites with false discovery rate (FDR) less than 0.05 and absolute percent methylation difference greater than 5% were considered as significant. Results: Following knockdown of DNMT3a for 72 h, differentially methylated regions were identified in the promoter CpG sites of Myh7, Myh7b, Tnni3, Tnnt2, Nppa, Nppb, Mef2c, Mef2d, and Cdkn1C. Following knockdown of DNMT3b expression for 72 h, differentially methylated regions were identified in the promoter CpG sites of Myh6, Myh7b, Tnni3, Tnnt2, Nppa, Nppb, Mef2d, Cdkn1A, and Cdkn1C.

Dataset Information

Mus musculus

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