Green Benjamin B, Kerr David E
Terrill Hall, University of Vermont, 570 Main Street, Burlington 05405, United States.
Terrill Hall, University of Vermont, 570 Main Street, Burlington 05405, United States.
Vet Immunol Immunopathol. 2014 Jan 15;157(1-2):49-58. doi: 10.1016/j.vetimm.2013.10.015. Epub 2013 Oct 31.
The innate immune signaling pathway plays a crucial role in the recognition and early response to pathogens associated with disease. Genetic analysis has been unable to completely account for individual variability in the strength of the innate immune response. The aim of this study was to determine the role of the epigenetic markers (DNA methylation or histone acetylation) in controlling bovine gene expression in relation to the response to lipopolysaccharide (LPS). To determine the impact epigenetics may have in controlling innate immunity, dermal fibroblasts from fifteen dairy heifers having previously displayed a differential response to LPS were exposed to 5-aza-2'-deoxycytidine (AZA) and trichostatin A (TSA); de-methylating and hyper-acetylating agents, respectively. The AZA-TSA exposure resulted in a loss of variability between individuals' response to LPS as measured by fibroblast IL-8 protein production. Transcriptomic analysis by microarray was used to elucidate the role of epigenetics in innate immune signaling at 2, 4, and 8h post-LPS exposure. A subset of genes displayed altered expression due to AZA-TSA alone, suggesting an epigenetic regulatory element modifying expression under normal conditions. Treatment with AZA-TSA also led to increased expression of IL-8 (7.0-fold), IL-6 (2.5-fold), TNF-α (1.6-fold), and serum amyloid A 3 (SAA3) (11.3-fold) among other genes compared to control cultures for at least one of the measured times following LPS exposure. These data support the conclusion that epigenetic regulation significantly alters LPS-induced responses and constitutive cytokine gene expression.
天然免疫信号通路在识别与疾病相关的病原体并做出早期反应中起着至关重要的作用。基因分析无法完全解释天然免疫反应强度的个体差异。本研究的目的是确定表观遗传标记（DNA甲基化或组蛋白乙酰化）在控制牛基因表达与脂多糖（LPS）反应方面的作用。为了确定表观遗传学在控制天然免疫中可能产生的影响，将先前对LPS表现出不同反应的15头奶牛小母牛的皮肤成纤维细胞分别暴露于5-氮杂-2'-脱氧胞苷（AZA）和曲古抑菌素A（TSA）；分别为去甲基化剂和高乙酰化剂。通过成纤维细胞IL-8蛋白产生来衡量，AZA-TSA暴露导致个体对LPS反应之间的变异性丧失。在LPS暴露后2、4和8小时，使用微阵列进行转录组分析以阐明表观遗传学在天然免疫信号传导中的作用。一部分基因仅由于AZA-TSA而表现出表达改变，这表明在正常条件下存在修饰表达的表观遗传调控元件。与对照培养物相比，在LPS暴露后的至少一个测量时间点，用AZA-TSA处理还导致IL-8（7.0倍）、IL-6（2.5倍）、TNF-α（1.6倍）和血清淀粉样蛋白A 3（SAA3）（11.3倍）等其他基因的表达增加。这些数据支持这样的结论，即表观遗传调控显著改变LPS诱导的反应和组成型细胞因子基因表达。
