ACADSB-dependent skeletal muscle gene expression in relation to cardiorespiratory fitness

摘要 心肺适合度(CRF)较高的个体肥胖率和 心脏代谢性疾病，经年龄调整和疾病调整后的死亡率显著降低。给定 肥胖率和心脏代谢性疾病的增加以及这些疾病对 生活质量和医疗保健系统，有必要了解内在的分子机制 有助于更高的健康表型。尽管有人预测慢性肾功能衰竭具有高度的遗传性，但事实并非如此 未知特定基因的遗传如何有助于与慢性肾衰相关的健康和长寿。 为了研究慢性肾功能衰竭的遗传遗传性，我们实验室一直在研究一种高(Hcr)和低(Hcr)饲养的大鼠 (LCR)CRF通过世代选择育种来适应起源于遗传异质性的 股票。HCR大鼠具有人类高CRF表型特征，包括苗条、长寿和表达增加 与线粒体氧化磷酸化、脂肪酸代谢和支链相关的基因 骨骼肌中的氨基酸(BCAA)代谢。遗传和表型的异质性是保守的 在hcr和lcr品系中，通过轮换育种，使得基因和 表型可以研究。骨骼肌中表达最高和持续上调的基因之一 HCR大鼠是ACADSB，是一种支链氨基酸和短链FA分解代谢酶，其关键终末代谢产物是 丙酸。未发表的基因分型研究已经确定了具有统计学意义的QTL和eQTL之间的关联 ACADSB附近的一个等位变异。我们假设ACADSB调节与以下相关的基因的表达 氧化代谢和降低疾病风险的部分原因是丙酸的生成增加，一种HDAC- 抑制物，在骨骼肌中。具体地说，HCR大鼠更高地表达ACADSB的较短剪接变体， 提出了一个问题，即HCR相关的异构体或ACADSB总浓度是否有可能 导致基因表达的差异。我的项目将通过(1)过度表达LCR和HCR来检验这一假设- HCR和LCR大鼠骨骼肌中ACADSB的相关剪接变体，评估全局 RNA-Seq检测骨骼肌基因表达的变化及代谢通量的变化 通过ACADSB，以及(2)用丙酸补充HCR和LCR大鼠以评估全局转录 染色质组蛋白翻译后修饰的调节和变化。

ABSTRACT Individuals with higher cardiorespiratory fitness (CRF) experience decreased rates of obesity and cardiometabolic disease and show significantly lower age-adjusted and disease-adjusted mortality. Given the increasing rates of obesity and cardiometabolic disease and the negative consequences of these diseases on quality of life and the healthcare system, there is a need to understand the intrinsic molecular mechanisms that contribute to the higher fitness phenotype. Although it is predicted that CRF is highly genetically heritable, it is unknown how the inheritance of specific genes contributes to the health and longevity associated with CRF. To study the genetic heritability of CRF, our lab has been characterizing a rat bred for high (HCR) and low (LCR) CRF via generational selective breeding for fitness which originated from a genetically heterogeneous stock. HCR rats phenocopy high-CRF traits in humans including leanness, longevity, and increased expression of genes related to mitochondrial oxidative phosphorylation, fatty acid (FA) metabolism, and branch chain amino acid (BCAA) metabolism in the skeletal muscle. Genetic and phenotypic heterogeneity is conserved within the HCR and LCR lines through rotational breeding, such that the interaction between genes and phenotype can be studied. One of the most highly and consistently upregulated genes in the skeletal muscle of HCR rats is ACADSB, a BCAA and short-chain FA catabolic enzyme whose key end metabolic product is propionate. Unpublished genotyping studies have identified statistically significant QTL and eQTL associations of an allelic variant near ACADSB. We hypothesize that ACADSB regulates the expression of genes related to oxidative metabolism and reduced disease risk in part by increased generation of propionate, an HDAC- inhibitor, in skeletal muscle. Specifically, HCR rats more highly express a shorter splice variant of ACADSB, raising the question of whether the HCR-associated isoform, or the total ACADSB concentration, potentially leads to differential gene expression. My project will test this hypothesis by (1) overexpressing LCR and HCR- associated splice variants of ACADSB in the skeletal muscle of both HCR and LCR rats, assessing the global changes in skeletal muscle gene expression with RNA-Seq, and observing the changes in metabolic flux through ACADSB, and (2) supplementing HCR and LCR rats with propionate to assess global transcriptional regulation and changes in chromatin histone post-translational modifications.