Heart RNA-Seq of cardiomyocyte-specific and inducible Prmt5 knockout mouse model, nuclear sequencing without treatment

Our study introduces a novel animal model featuring a cardiomyocyte-specific, inducible knockout of the Prmt5. The primary aim of this model is to investigate the regulatory mechanisms of PRMT5, the main representative of type II PRMTs. We found that PRMT5 controls Acadvl mRNA splicing, and that disruptions in this regulation lead to loss of functional ACADVL and cardiac dysfunction. Importantly, we also show that maintained expression of ACADVL is cardioprotective highlighting a potential therapeutic strategy. The animal model was created using a conditional-ready allele of Prmt5 sourced from the European Mouse Mutant Archive (EMMA, specifically the B6Brd;B6N-Tyrc-Brd Atm1Brd Prmt5tm2a(EUCOMM)WtsiPrmt5 strain). To achieve a conditional knockout, the lacZ reporter was excised using flippase recombinase. The resulting Prmt5loxP/loxP mice were then bred with transgenic mice expressing an inducible Cre recombinase under the control of the alpha-myosin heavy chain promoter (alpha-MHC-MerCreMer), enabling deletion of Prmt5 in cardiomyocytes. To test the hypothesis that the cardiac phenotype was driven by downregulation of ACADVL, we use preventive treatment with AVV9-containing ACADVL cDNA sequence, which restores ACADVL protein expression (day 0). This treatment was followed with tamoxifen treatment from day 5 to day 17. On day 38, animals were treated with NaCl (control) or Isoprenaline (ISO) for 10 days. Moreover, this model allows the study of PRMT5 derived heart failure, and allowed us to determine which molecular pathways are related to the phenotype.

本研究构建了一种全新的动物模型，该模型可实现蛋白精氨酸甲基转移酶5（Protein Arginine Methyltransferase 5, Prmt5）在心肌细胞中的特异性诱导性敲除。该模型的核心研究目标为探究II型蛋白精氨酸甲基转移酶（type II PRMTs）的主要代表分子PRMT5的调控机制。本研究发现，PRMT5可调控Acadvl的mRNA剪接过程，该调控通路的紊乱会导致功能性ACADVL的缺失以及心脏功能异常。尤为重要的是，本研究同时证实，维持ACADVL的表达具有心脏保护作用，这为相关治疗策略的开发提供了潜在方向。本研究所用的动物模型，采用源自欧洲小鼠突变体库（European Mouse Mutant Archive, EMMA）的Prmt5条件性敲除预备等位基因构建，具体品系为B6Brd;B6N-Tyrc-Brd Atm1Brd Prmt5tm2a(EUCOMM)WtsiPrmt5。为获得条件性敲除模型，研究人员利用翻转酶重组酶切除了lacZ报告基因。将获得的Prmt5loxP/loxP小鼠与在α-肌球蛋白重链启动子（alpha-myosin heavy chain promoter, α-MHC）调控下表达诱导型Cre重组酶的转基因小鼠（alpha-MHC-MerCreMer）进行交配，从而实现Prmt5在心肌细胞中的特异性敲除。为验证"心脏表型由ACADVL表达下调所驱动"这一假说，研究人员于第0天采用携带ACADVL cDNA序列的AVV9进行预防性干预，以恢复ACADVL的蛋白表达。在该干预完成后，研究人员于第5天至第17天对小鼠进行他莫昔芬给药处理。于第38天，分别对小鼠给予氯化钠（对照组）或异丙肾上腺素（Isoprenaline, ISO）处理，持续10天。此外，该模型可用于PRMT5相关心力衰竭的相关研究，同时帮助研究人员明确与该心脏表型相关的分子通路。