ABSTRACT

Increased visceral adipose tissue (VAT) is associated with metabolic dysfunction, while subcutaneous adipose tissue (SAT) is considered protective. The mechanisms underlying these differences are not fully elucidated. This study aimed to investigate molecular differences in VAT and SAT of male Wistar rats fed a cafeteria diet (CD) or a standard rodent diet (STD) for three months. The expression of fatty acid metabolism genes was analysed by quantitative real-time PCR. Global and gene-specific DNA methylation was quantified using the Imprint® Methylated DNA Quantification Kit and pyrosequencing, respectively. Bodyweight, retroperitoneal fat mass, insulin resistance, leptin and triglyceride concentrations and adipocyte hypertrophy were higher in CD- compared to STD-fed rats. The expression of solute carrier family 27 member 3 (Slc27a3), a fatty acid transporter, was 9.6-fold higher in VAT and 6.3-fold lower in SAT of CD- versus STD-fed rats. Taqman probes confirmed increased Slc27a3 expression, while pyrosequencing showed Slc27a3 hypomethylation in VAT of CD- compared to STD-fed rats. The CD decreased global methylation in both VAT and SAT, although no depot differences were observed. Dysregulated fatty acid influx in VAT, in response to a CD, provides insight into the mechanisms underlying depot-differences in adipose tissue expansion during obesity and metabolic disease.

Abbreviations: CD: cafeteria diet; E2F1: E2F Transcription Factor 1; EMSA: electrophoretic mobility shift assay; EGFR: epidermal growth factor receptor; GCF: GC-Rich Sequence DNA-Binding Factor; HOMA-IR: Homeostasis model for insulin resistance; NKX2-1: NK2 homeobox 1; PCR: Polymerase chain reaction; qRT-PCR: quantitative real-time PCR; RF: retroperitoneal fat; SAT: subcutaneous adipose tissue; Slc27a3: solute carrier family 27 member 3; STD: standard diet; TNFα: tumour necrosis factor alpha; TTS: transcriptional start site; T2D: Type 2 Diabetes; VAT: visceral adipose tissue; WT1 I: Wilms’ tumour protein 1

摘要

增加的内脏脂肪组织 (VAT) 与代谢功能障碍有关，而皮下脂肪组织 (SAT) 被认为具有保护作用。这些差异背后的机制尚未完全阐明。本研究旨在调查喂食自助餐厅饮食 (CD) 或标准啮齿动物饮食 (STD) 三个月的雄性 Wistar 大鼠的 VAT 和 SAT 的分子差异。通过定量实时PCR分析脂肪酸代谢基因的表达。分别使用 Imprint® 甲基化 DNA 定量试剂盒和焦磷酸测序对全局和基因特异性 DNA 甲基化进行定量。与 STD 喂养的大鼠相比，CD 组的体重、腹膜后脂肪量、胰岛素抵抗、瘦素和甘油三酯浓度以及脂肪细胞肥大更高。溶质载体家族 27 成员 3 (Slc27a3) 的表达，一种脂肪酸转运蛋白，CD 喂养大鼠与 STD 喂养大鼠的增值税高 9.6 倍，SAT 低 6.3 倍。Taqman 探针证实 Slc27a3 表达增加，而焦磷酸测序显示与 STD 喂养的大鼠相比，CD- 的 VAT 中 Slc27a3 低甲基化。CD 降低了 VAT 和 SAT 中的全球甲基化，尽管没有观察到仓库差异。为响应 CD，VAT 中失调的脂肪酸流入提供了对肥胖和代谢疾病期间脂肪组织扩张的库差异潜在机制的深入了解。虽然没有观察到仓库差异。为响应 CD，VAT 中失调的脂肪酸流入提供了对肥胖和代谢疾病期间脂肪组织扩张的库差异潜在机制的深入了解。虽然没有观察到仓库差异。为响应 CD，VAT 中失调的脂肪酸流入提供了对肥胖和代谢疾病期间脂肪组织扩张的库差异潜在机制的深入了解。

缩写： CD：食堂饮食；E2F1：E2F 转录因子 1；EMSA：电泳迁移率变化测定；EGFR：表皮生长因子受体；GCF：富含GC的序列DNA结合因子；HOMA-IR：胰岛素抵抗的稳态模型；NKX2-1：NK2同源盒1；PCR：聚合酶链反应；qRT-PCR：定量实时PCR；RF：腹膜后脂肪；SAT：皮下脂肪组织；Slc27a3：溶质载体家族 27 成员 3；STD：标准饮食；TNFα：肿瘤坏死因子α；TTS：转录起始位点；T2D：2 型糖尿病；VAT：内脏脂肪组织；WT1 I：维尔姆斯肿瘤蛋白 1