背景:高脂血症是一种脂质代谢紊乱,在全球范围内发病率和患病率都在增加。脂质代谢异常和炎症是高脂血症的两个显著特征。目的探讨F-boxonly蛋白28(FBXO28)在高脂血症中的作用及机制。
方法:用高脂饮食(HFD)喂养小鼠以引起肥胖,用MDI混合物刺激3T3-L1前脂肪细胞(IBMX,DEX和胰岛素)引起分化。通过苏木精-伊红和油红O染色研究了FBXO28在高脂血症中的体内和体外作用,脂质生物化学测量,酶联免疫吸附测定,逆转录定量聚合酶链反应和蛋白质印迹分析。通过免疫共沉淀探索FBXO28的机制,免疫荧光,泛素化和环己酰亚胺测定。
结果:在高脂血症中发现FBXO28低表达,体内和体外。FBXO28的上调降低了体重,脂肪堆积,和HFD喂养小鼠的血清脂质含量。异常脂质积累,在HFD引起的小鼠和MDI处理的3T3-L1前脂肪细胞中,通过过表达FBXO28可以提高脂肪合成基因和β氧化相关基因的水平。此外,FBXO28的过表达降低了HFD诱导的促炎因子和F4/80的水平。机械上,FBXO28直接结合RAB27A并促进其泛素化降解。因此,RAB27A的上调逆转了FBXO28在体内和体外异常脂质代谢和炎症中的作用。
结论:FBXO28通过RAB27A的泛素化降解改善了异常的脂质代谢和炎症,从而减弱HFD诱导的高脂血症。结果可促进高脂血症的治疗,以及相关疾病。
BACKGROUND: Hyperlipidemia is a lipid metabolism disorder with increasing incidence and prevalence worldwide. Abnormal lipid metabolism and inflammation are two significant characteristics of hyperlipidemia. The purpose of this study was to explore the role and mechanism of F-box only protein 28 (
FBXO28) in hyperlipidemia.
METHODS: Mice were fed with high-fat diet (HFD) to elicit obesity, and 3T3-L1 preadipocytes were stimulated with MDI cocktail (IBMX, DEX and insulin) to evoke differentiation. In vivo and in vitro role of
FBXO28 in hyperlipidemia was investigated by hematoxylin-eosin and oil Red O staining, the lipid biochemistry measurement, enzyme-linked immunosorbent assay, reverse transcription quantitative polymerase chain reaction and western blotting assays. The mechanism of FBXO28 explored by co-immunoprecipitation, immunofluorescence, ubiquitination and cycloheximide assays.
RESULTS: Low expression of FBXO28 was found in hyperlipidemia in silico, in vivo and in vitro. Upregulation of
FBXO28 declined the body weight, fat accumulation, and serum lipid content in HFD-fed mice. Abnormal lipid accumulation, and the level of liposynthetic genes and beta-oxidation related genes were improved by overexpression of FBXO28 both in HFD-elicited mice and MDI-treated 3T3-L1 preadipocytes. Besides, overexpression of
FBXO28 declined HFD-induced the level of proinflammatory factors and F4/80. Mechanically,
FBXO28 directly bound RAB27A and promoted its ubiquitinated degradation. Thus, upregulation of RAB27A inverted the improved role of FBXO28 in abnormal lipid metabolism and inflammation in vivo and in vitro.
CONCLUSIONS: FBXO28 ameliorated abnormal lipid metabolism and inflammation through the ubiquitinated degradation of RAB27A, thereby attenuating HFD-induced hyperlipidemia. The results could promote the treatment of hyperlipidemia, and the relevant diseases.