Gene expression-based assessment of the effect of PQQ

Pyrroloquinoline quinone (PQQ) is a naturally occurring compound and known to improve growth and reproductive performance when added to diets of PQQ-deprived rodents. To understand its mechanism of action, changes in hepatic gene expression were measured in rats fed diets with or without added PQQ. Of the ~10,000 genes and ESTs analyzed, 4.7% of the transcripts were sensitive to changes in PQQ dietary status. PQQ deprivation generally caused downregulation of genes associated with mitochondriogenesis, cell differentiation, and immune function. These gene expression changes provide the basis for most of the previously published functional observations associated with PQQ deficiency and PQQ administered in pharmacological amounts. To assess PQQ’s potential functions, we used gene expression profiling through microarray technology as part of a comprehensive approach to identify potential pathways and mechanisms. Given that the systemic effects of PQQ deprivation are influenced at levels of dietary intake in the micromolar range, highly purified diets were used to reduce expression from other bioactive factors and xenobiotics, such as those found in typical rodent chow diets. Dietary conditions were also chosen to clarify the response to PQQ deprivation. A goal was to determine if specific changes in dietary protocol or patterns could be used to identify genes important to the function of PQQ. Because it has been observed that mitochondrial-related functions are influenced by PQQ, we hypothesized that changes in genes important to fatty acid and amino acid metabolism and mitochondrial function would be likewise affected by dietary levels of PQQ. The overall study was carried out using two experiments. In this specific experiment, PQQ depletion and repletion was studied to understand the effect of PQQ on gene expression.吡咯并喹啉醌（Pyrroloquinoline quinone, PQQ）是一种天然存在的化合物，已知将其添加至缺乏PQQ的啮齿动物饲料中时，可改善受试动物的生长与繁殖性能。为阐明其作用机制，本研究对喂食添加或不添加PQQ饲料的大鼠的肝脏基因表达变化进行了检测。在分析的约10000个基因与表达序列标签（EST）中，4.7%的转录本对饲料中PQQ的摄入状态变化敏感。PQQ缺乏通常会导致与线粒体发生、细胞分化以及免疫功能相关的基因表达下调。这些基因表达变化为此前已发表的大多数与PQQ缺乏及药理学剂量PQQ给药相关的功能观察结果提供了理论依据。为评估PQQ的潜在功能，我们通过微阵列（microarray）技术开展基因表达谱分析，以此作为综合识别潜在通路与作用机制的研究手段之一。鉴于PQQ缺乏的全身效应受微摩尔级膳食摄入量的影响，本研究使用了高度纯化的饲料，以减少典型啮齿动物饲料中常见的其他生物活性因子与外源性物质所带来的表达干扰。同时，我们通过设定特定饲料条件，明确机体对PQQ缺乏的响应。本研究的目标之一是探明是否可通过特定的饲料方案或模式，识别出与PQQ功能密切相关的基因。已有研究表明线粒体相关功能受PQQ调控，因此我们提出假设：与脂肪酸、氨基酸代谢及线粒体功能相关的重要基因，同样会受到饲料中PQQ水平的影响。本整体研究通过两项实验开展。在本次特定实验中，我们对PQQ的耗竭与补充进行了研究，以阐明PQQ对基因表达的调控作用。