Institutes of Physiology, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan; Department of Life Science, College of Science, Chinese Culture University, Taipei, Taiwan.
School of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan; Division of Cardiology, Cheng-Hsin General Hospital, Taipei, Taiwan; Heart Center, Cheng-Hsin General Hospital, Taipei, Taiwan.
Biochim Biophys Acta Mol Cell Biol Lipids. 2022 Feb;1867(2):159071. doi: 10.1016/j.bbalip.2021.159071. Epub 2021 Nov 5.
Endothelin-1 (ET-1) is a potent vasoconstrictive peptide produced and secreted mainly by endothelial cells. Recent studies indicate that ET-1 can regulate lipid metabolism, which may increase the risk of insulin resistance. Our previous studies revealed that ET-1 induced lipolysis in adipocytes, but the underlying mechanisms were unclear. 3T3-L1 adipocytes were used to investigate the effect of ET-1 on lipolysis and the underlying mechanisms. Glycerol levels in the incubation medium and hormone-sensitive lipase (HSL) phosphorylation were used as indices for lipolysis. ET-1 significantly increased HSL phosphorylation and lipolysis, which were completely inhibited by ERK inhibitor (PD98059) and guanylyl cyclase (GC) inhibitor (LY83583). LY83583 reduced ET-1-induced ERK phosphorylation. A Ca-free medium and PLC inhibitor caused significant decreases in ET-1-induced lipolysis as well as ERK and HSL phosphorylation, and IP receptor activator (D-IP) increased lipolysis. ET-1 increased cGMP production, which was not affected by depletion of extracellular Ca. On the other hand, LY83583 diminished the ET-1-induced Ca influx. Transient receptor potential vanilloid-1 (TRPV-1) antagonist and shRNA partially inhibited ET-1-induced lipolysis. ET-1-induced lipolysis was completely suppressed by CaMKIII inhibitor (NH-125). These results indicate that ET-1 stimulates extracellular Ca entry and activates the intracellular PLC/IP/Ca pathway through a cGMP-dependent pathway. The increased cytosolic Ca that results from ET-1 treatment stimulates ERK and HSL phosphorylation, which subsequently induces lipolysis. ET-1 induces HSL phosphorylation and lipolysis via the GC/cGMP/Ca/ERK/CaMKIII signaling pathway in 3T3-L1 adipocytes.
内皮素-1（ET-1）是一种主要由内皮细胞产生和分泌的强效血管收缩肽。最近的研究表明，ET-1 可以调节脂质代谢，这可能增加胰岛素抵抗的风险。我们之前的研究表明，ET-1 可诱导脂肪细胞脂肪分解，但具体机制尚不清楚。我们使用 3T3-L1 脂肪细胞来研究 ET-1 对脂肪分解的影响及其潜在机制。孵育培养基中的甘油水平和激素敏感脂肪酶（HSL）磷酸化被用作脂肪分解的指标。ET-1 显著增加了 HSL 的磷酸化和脂肪分解，而 ERK 抑制剂（PD98059）和鸟苷酸环化酶（GC）抑制剂（LY83583）则完全抑制了这一作用。LY83583 降低了 ET-1 诱导的 ERK 磷酸化。无钙培养基和 PLC 抑制剂显著降低了 ET-1 诱导的脂肪分解以及 ERK 和 HSL 的磷酸化，而 IP 受体激动剂（D-IP）增加了脂肪分解。ET-1 增加了 cGMP 的产生，而细胞外钙的耗竭对其没有影响。另一方面，LY83583 减弱了 ET-1 诱导的钙内流。瞬时受体电位香草醛 1（TRPV-1）拮抗剂和 shRNA 部分抑制了 ET-1 诱导的脂肪分解。钙调蛋白激酶 III 抑制剂（NH-125）完全抑制了 ET-1 诱导的脂肪分解。这些结果表明，ET-1 通过 cGMP 依赖途径刺激细胞外钙进入，并激活细胞内 PLC/IP/Ca 途径。ET-1 处理引起的细胞内钙增加刺激了 ERK 和 HSL 的磷酸化，从而诱导脂肪分解。ET-1 通过 3T3-L1 脂肪细胞中的 GC/cGMP/Ca/ERK/CaMKIII 信号通路诱导 HSL 磷酸化和脂肪分解。
