ABSTRACT

Obesity promotes dysfunction and impairs the reparative capacity of mesenchymal stem/stromal cells (MSCs), and alters their transcription, protein content, and paracrine function. Whether these adverse effects are mediated by chromatin-modifying epigenetic changes remains unclear. We tested the hypothesis that obesity imposes global DNA hydroxymethylation and histone tri-methylation alterations in obese swine abdominal adipose tissue-derived MSCs compared to lean pig MSCs. MSCs from female lean (n = 7) and high-fat-diet fed obese (n = 7) domestic pigs were assessed using global epigenetic assays, before and after in-vitro co-incubation with the epigenetic modulator vitamin-C (VIT-C) (50 μg/ml). Dot blotting was used to measure across the whole genome 5-hydroxyemthycytosine (5hmC) residues, and Western blotting to quantify in genomic histone-3 protein tri-methylated lysine-4 (H3K4me3), lysine-9 (H3K9me3), and lysine-27 (H3K27me3) residues. MSC migration and proliferation were studied in-vitro. Obese MSCs displayed reduced global 5hmC and H3K4m3 levels, but comparable H3K9me3 and H3K27me3, compared to lean MSCs. Global 5hmC, H3K4me3, and HK9me3 marks correlated with MSC migration and reduced proliferation, as well as clinical and metabolic characteristics of obesity. Co-incubation of obese MSCs with VIT-C enhanced 5hmC marks, and reduced their global levels of H3K9me3 and H3K27me3. Contrarily, VIT-C did not affect 5hmC, and decreased H3K4me3 in lean MSCs. Obesity induces global genomic epigenetic alterations in swine MSCs, involving primarily genomic transcriptional repression, which are associated with MSC function and clinical features of obesity. Some of these alterations might be reversible using the epigenetic modulator VIT-C, suggesting epigenetic modifications as therapeutic targets in obesity.

摘要

肥胖会促进功能障碍并损害间充质干/基质细胞 (MSC) 的修复能力，并改变其转录、蛋白质含量和旁分泌功能。这些不良反应是否由染色质修饰的表观遗传变化介导仍不清楚。我们检验了与瘦猪 MSCs 相比，肥胖会在肥胖猪腹部脂肪组织衍生的 MSCs 中产生全局 DNA 羟甲基化和组蛋白三甲基化改变的假设。在与表观遗传调节剂维生素 C (VIT- C) (50 微克/毫升)。斑点印迹用于测量整个基因组的 5-羟甲基胞嘧啶 (5hmC) 残基，和蛋白质印迹以量化基因组组蛋白 3 蛋白三甲基化赖氨酸 4 (H3K4me3)、赖氨酸 9 (H3K9me3) 和赖氨酸 27 (H3K27me3) 残基。体外研究了MSC迁移和增殖。与瘦的 MSC 相比，肥胖的 MSC 显示出降低的全球 5hmC 和 H3K4m3 水平，但 H3K9me3 和 H3K27me3 相当。全球 5hmC、H3K4me3 和 HK9me3 标记与 MSC 迁移和增殖减少以及肥胖的临床和代谢特征相关。肥胖 MSCs 与 VIT-C 的共同孵化增强了 5hmC 标记，并降低了其 H3K9me3 和 H3K27me3 的整体水平。相反，VIT-C 不影响 5hmC，并降低瘦 MSCs 中的 H3K4me3。肥胖诱导猪 MSCs 的全球基因组表观遗传改变，主要涉及基因组转录抑制，这与 MSC 功能和肥胖的临床特征有关。使用表观遗传调节剂 VIT-C，其中一些改变可能是可逆的，这表明表观遗传修饰是肥胖症的治疗靶点。