Fu Changzhen, Xiang Meng-Lin, Chen Shaolang, Dong Geng, Liu Zibo, Chen Chong-Bo, Liang Jiajian, Cao Yingjie, Zhang Mingzhi, Liu Qingping
Joint Shantou International Eye Center of Shantou University and The Chinese University of Hong Kong, Shantou, Guangdong Province 515041, China.
Shantou University Medical College, Shantou, Guangdong Province 515031, China.
ACS Omega. 2023 Jul 28;8(31):28277-28289. doi: 10.1021/acsomega.3c02082. eCollection 2023 Aug 8.
Long-chain fatty acids (LCFAs) are one of the main energy-supplying substances in the body. LCFAs with different lengths and saturations may have contrasting biological effects that exacerbate or alleviate progress against a variety of systemic disorders of lipid metabolism in organisms. Nonalcoholic fatty liver disease is characterized by chronic inflammation and steatosis, mainly caused by the ectopic accumulation of lipids in the liver, especially LCFAs. CD36 is a scavenger receptor that recognizes and mediates the transmembrane absorption of LCFAs and is expressed in a variety of cells throughout the body. In previous studies, our group found that 7-ketocholesteryl-9-carboxynonanoate (oxLig-1) has the biological effect of targeting CD36 to inhibit oxidized low-density lipoprotein lipotoxicity-induced lipid metabolism disorder; it has an ω-carboxyl physiologically active center and is structurally similar to LCFAs. However, the biological mechanism of oxLig-1 binding to CD36 and competing for binding to different types of LCFAs is still not clear. In this study, molecular docking and molecular dynamics simulation were utilized to simulate and analyze the binding activity between oxLig-1 and different types of LCFAs to CD36 and confirmed by the enzyme-linked immunosorbent assay (ELISA) method. Absorption, distribution, metabolism, excretion, and toxicity (ADMET) platform was applied to predict the drug-forming properties of oxLig-1, and HepG2 cells model of oleic acid and nonalcoholic fatty liver disease (NAFLD) model mice were validated to verify the biological protection of oxLig-1 on lipid lowering. The results showed that there was a co-binding site of LCFAs and oxLig-1 on CD36, and the binding driving forces were mainly hydrogen bonding and hydrophobic interactions. The binding abilities of polyunsaturated LCFAs, oxLig-1, monounsaturated LCFAs, and saturated LCFAs to CD36 showed a decreasing trend in this order. There was a similar decreasing trend in the stability of the molecular dynamics simulation. ELISA results similarly confirmed that the binding activity of oxLig-1 to CD36 was significantly higher than that of typical monounsaturated and saturated LCFAs. ADMET prediction results indicated that oxLig-1 had a good drug-forming property. HepG2 cells model of oleic acid and NAFLD model mice study results demonstrated the favorable lipid-lowering biological effects of oxLig-1. Therefore, oxLig-1 may have a protective effect by targeting CD36 to inhibit the excessive influx and deposition of lipotoxicity monounsaturated LCFAs and saturated LCFAs in hepatocytes.
长链脂肪酸(LCFAs)是体内主要的能量供应物质之一。不同长度和饱和度的长链脂肪酸可能具有相反的生物学效应,会加剧或缓解生物体脂质代谢各种系统性紊乱的进展。非酒精性脂肪性肝病的特征是慢性炎症和脂肪变性,主要由肝脏中脂质的异位积累引起,尤其是长链脂肪酸。CD36是一种清道夫受体,可识别并介导长链脂肪酸的跨膜吸收,在全身多种细胞中表达。在先前的研究中,我们团队发现7-酮胆固醇基-9-羧基壬酸酯(oxLig-1)具有靶向CD36以抑制氧化型低密度脂蛋白脂毒性诱导的脂质代谢紊乱的生物学效应;它具有ω-羧基生理活性中心,在结构上与长链脂肪酸相似。然而,oxLig-1与CD36结合并竞争与不同类型长链脂肪酸结合的生物学机制仍不清楚。在本研究中,利用分子对接和分子动力学模拟来模拟和分析oxLig-1与不同类型长链脂肪酸对CD36的结合活性,并通过酶联免疫吸附测定(ELISA)方法进行验证。应用吸收、分布、代谢、排泄和毒性(ADMET)平台预测oxLig-1的成药特性,并通过油酸HepG2细胞模型和非酒精性脂肪性肝病(NAFLD)模型小鼠进行验证,以证实oxLig-1对降脂的生物学保护作用。结果表明,长链脂肪酸和oxLig-1在CD36上存在共同结合位点,结合驱动力主要是氢键和疏水相互作用。多不饱和长链脂肪酸、oxLig-1、单不饱和长链脂肪酸和饱和长链脂肪酸对CD36的结合能力按此顺序呈下降趋势。分子动力学模拟的稳定性也有类似的下降趋势。ELISA结果同样证实,oxLig-1与CD36的结合活性明显高于典型的单不饱和和饱和长链脂肪酸。ADMET预测结果表明oxLig-1具有良好的成药特性。油酸HepG2细胞模型和NAFLD模型小鼠的研究结果证明了oxLig-1具有良好的降脂生物学效应。因此,oxLig-1可能通过靶向CD36来抑制脂毒性单不饱和长链脂肪酸和饱和长链脂肪酸在肝细胞中的过度流入和沉积,从而发挥保护作用。