Department of Endocrinology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
Hubei Provincial Clinical Research Center for Diabetes and Metabolic Disorders, Wuhan, China.
Am J Physiol Endocrinol Metab. 2020 Dec 1;319(6):E1031-E1043. doi: 10.1152/ajpendo.00090.2020. Epub 2020 Sep 21.
Caloric restriction (CR) followed by refeeding, a phenomenon known as catch-up growth (CUG), results in excessive lipid deposition and insulin resistance in skeletal muscle, but the underlying mechanisms remain elusive. Recent reports have suggested that vascular endothelial growth factor B (VEGF-B) controls muscle lipid accumulation by regulating endothelial fatty acid transport. Here, we found continuous activation of VEGF-B signaling and increased lipid uptake in skeletal muscle from CR to refeeding, as well as increased lipid deposition and impaired insulin sensitivity after refeeding in the skeletal muscle of CUG rodents. Inhibiting VEGF-B signaling reduced fatty acid uptake in and transport across endothelial cells. Knockdown of in the tibialis anterior (TA) muscle of CUG mice significantly attenuated muscle lipid accumulation and ameliorated muscle insulin sensitivity by decreasing lipid uptake. Furthermore, we showed that aberrant histone methylation (H3K9me1) and acetylation (H3K14ac and H3K18ac) at the promoter might be the main cause of persistent VEGF-B upregulation in skeletal muscle during CUG. Modifying these aberrant loci using their related enzymes [PHD finger protein 2 (PHF2) or E1A binding protein p300 (p300)] could regulate VEGF-B expression in vitro. Collectively, our findings indicate that VEGF-B can promote transendothelial lipid transport and lead to lipid overaccumulation and insulin resistance in skeletal muscle during CUG, which might be mediated by histone methylation and acetylation.
热量限制(CR)后再喂养,即所谓的追赶生长(CUG),会导致骨骼肌中脂质过度沉积和胰岛素抵抗,但潜在机制仍不清楚。最近的报告表明,血管内皮生长因子 B(VEGF-B)通过调节内皮细胞脂肪酸转运来控制肌肉脂质积累。在这里,我们发现从 CR 到再喂养,VEGF-B 信号持续激活,骨骼肌中脂质摄取增加,以及在 CUG 啮齿动物的骨骼肌中再喂养后脂质沉积增加和胰岛素敏感性受损。抑制 VEGF-B 信号可减少内皮细胞内和跨内皮细胞的脂肪酸摄取和转运。在 CUG 小鼠的比目鱼肌(TA)中敲低 ,通过减少脂质摄取,显著减轻肌肉脂质积累并改善肌肉胰岛素敏感性。此外,我们表明,在 CUG 期间, 启动子处的异常组蛋白甲基化(H3K9me1)和乙酰化(H3K14ac 和 H3K18ac)可能是骨骼肌中 VEGF-B 持续上调的主要原因。使用相关酶 [PHD 指蛋白 2(PHF2)或 E1A 结合蛋白 p300(p300)] 修饰这些异常位点可以调节体外的 VEGF-B 表达。总的来说,我们的研究结果表明,VEGF-B 可以促进跨内皮脂质转运,导致 CUG 期间骨骼肌中脂质过度积累和胰岛素抵抗,这可能是通过组蛋白甲基化和乙酰化介导的。