The effects of METTL3 on BAT development and thermogenesis

Purpose: The goal of this study is to compare transcriptome profilings of interscapular brown adipose tissue (iBAT) from BAT-specific METTL3 knockout and control mice Methods: iBATs were collected from METTL3 BKO and f/f mice at 8 weeks old, and total RNA was isolated using TriPure. RNA samples were pooled from iBATs of METTL3 BKO and f/f mice (n=4 for each group). RNA-seq was performed by using Illumina NovaSeq 6000 platform. Paired-end clean reads were aligned to the mouse reference genome (Ensemble_GRCm38.90) with TopHat (version 2.0.12), and the aligned reads were used to quantify mRNA expression by using HTSeq-count (version 0.6.1). Conclusion:Our study represents the first detailed analysis of iBAT transcriptomes from METTL3 BKO and f/f mice, generated by RNA-seq technology. The RNA-seq analysis showed that 530 genes were down-regulated and 1552 genes were up-regulated in the iBAT of METTL3 BKO mice. GO analysis showed that the down-regulated genes were primarily related to developmental maturation, respiratory electron transport chain, adaptive thermogenesis, and energy deprivation by oxidation of organic compounds whereas the up-regulated genes were associated with muscle system process and muscle cell development. RNA samples were pooled from iBATs of METTL3 BKO and f/f mice at 8 weeks old (n=4 for each group). mRNA profiles of METTL3 BKO and f/f iBATs were generated by deep sequencing, in a single test, using Illumina NovaSeq 6000 platform.研究目的：本研究旨在对比BAT特异性METTL3基因敲除（BAT-specific METTL3 knockout）小鼠与对照小鼠肩胛间棕色脂肪组织（interscapular brown adipose tissue，iBAT）的转录组谱。 实验方法：从8周龄的METTL3 BKO及f/f小鼠中采集肩胛间棕色脂肪组织，使用TriPure试剂提取总RNA。将两组小鼠（每组n=4）的肩胛间棕色脂肪组织的RNA样本分别混合，采用Illumina NovaSeq 6000平台进行RNA测序（RNA-seq）。将双端清洁读段比对至小鼠参考基因组（Ensemble_GRCm38.90），比对工具为TopHat（版本2.0.12），随后使用HTSeq-count（版本0.6.1）对比对得到的读段进行mRNA表达量定量。 研究结论：本研究首次通过RNA测序技术对METTL3 BKO及f/f小鼠的肩胛间棕色脂肪组织转录组进行了详细分析。RNA测序结果显示，METTL3 BKO小鼠肩胛间棕色脂肪组织中共有530个基因下调、1552个基因上调。基因本体分析（Gene Ontology，GO）结果表明，下调基因主要富集于发育成熟、呼吸电子传递链、适应性产热以及有机化合物氧化介导的能量剥夺等生物学过程；而上调基因则与肌肉系统过程及肌细胞发育相关。本研究同样收集了8周龄METTL3 BKO及f/f小鼠的肩胛间棕色脂肪组织（每组n=4）并混合其RNA样本，采用Illumina NovaSeq 6000平台通过单次深度测序获取了两组小鼠肩胛间棕色脂肪组织的mRNA表达谱。