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

摘要 心肺适能（CRF）较高的个体肥胖率降低， 心脏代谢疾病，并显示出显着降低年龄调整和疾病调整的死亡率。鉴于 肥胖症和心脏代谢疾病的发病率不断上升，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， 有助于更高的适应性表型。尽管预测CRF具有高度的遗传性， 目前尚不清楚特定基因的遗传如何促进与CRF相关的健康和长寿。 为了研究慢性肾功能衰竭的遗传力，本实验室对高（HCR）和低（HCR）饲养的大鼠进行了表征。 (LCR)CRF通过世代选择育种的健身起源于遗传异质性 车辆. HCR大鼠表型复制人类的高CRF特征，包括消瘦、长寿和表达增加 与线粒体氧化磷酸化、脂肪酸（FA）代谢和分支链相关的基因 氨基酸（BCAA）在骨骼肌中的代谢。遗传和表型异质性是保守的 在HCR和LCR系内通过旋转育种，使得基因和 表型可以研究。一个最高度和一致上调的基因在骨骼肌中， HCR大鼠是ACADSB，一种BCAA和短链FA分解代谢酶，其关键终末代谢产物是 丙酸盐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关联 ACADSB附近的等位基因变异我们假设ACADSB调节与以下相关基因的表达： 氧化代谢和降低疾病风险的部分原因是增加了丙酸盐的生成， 抑制剂，在骨骼肌中。具体而言，HCR大鼠更高地表达ACADSB的较短剪接变体， 这就提出了一个问题，即HCR相关亚型或总ACADSB浓度是否可能 导致基因表达的差异。我的项目将通过（1）过表达LCR和HCR- HCR和LCR大鼠骨骼肌中ACADSB的相关剪接变体， 用RNA-Seq检测骨骼肌基因表达的变化，并观察代谢通量的变化 通过ACADSB，和（2）补充丙酸HCR和LCR大鼠，以评估全球转录 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 Unpublished genotyping studies have identified statistically significant QTL and eQTL associations of an allelic variant near ACADSB.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.