Diosgenin Downregulates LPL Expression Through The Inhibition Of PI3K/AKT Impacting Lipid Accumulation In THP-1Macrophages

Background and purposeDiosgenin is active pharmaceutical ingredients of Viocin which consists of99.4%diosgenin, with lots of function such as anti-tumor, anti-infective, anti-lymphocyticleukemia, anti-cardiovascular disease, regulation of lipid metabolism and othereffects.Meanwhile, clinical reports indicate that diosgenin can delay formation of plaque,but the underlying mechanism has not been elucidated. Studies have shown that lipoproteinlipase expression in macrophages have caused atherosclerosis by promoting lipidaccumulation what suggest that diosgenin achieve anti-atherosclerosis function possiblythrough reduced lipoprotein lipase expression in macrophages.Therefore,the object of ourproject is that explore diosgenin anti-atherosclerotic mechanisms through researchingeffect of diosgenin on lipoprotein lipase expression in THP-1macrophages in order toprovide some theoretical guidance and experimental basis for diosgeninanti-atherosclerosis research and give some new ideas for the prevention and cure ofatherosclerosis.Methods(1)THP-1cells were cultured and induced differentiation: First choice RPMI-1640medium containing10%fetal bovine serum for THP-1cells were cultured, and thenTHP-1cells were incubated24h with160nmol/L PMA to make THP-1cells differentiateinto macrophages.(2)MTT method to explore diosgenin optimum concentration: differentconcentrations of diosgenin treated induced differentiation of THP-1macrophages for24h,and then MTT detected cell viability to determine the best treatment of diosgeninconcentration.(3)After different treatment of diosgenin time,PCR and Western Blot detected changes the expression of LPL in THP-1macrophage to determine the besttreatment of diosgenin time.(4)Oil red O staining method to detect THP-1macrophagelipid content after different treatment:after diosgenin treatment observed THP-1macrophage lipid content to know the effects of diosgenin on THP-1macrophages lipidaccumulation,and observed the effect of diosgenin on THP-1macrophage lipid contentwhich treated by LPL siRNA to verify THP-1macrophage lipid accumulation is affectedby diosgenin whether through LPL played.(5)After different treatment of LPL siRNA orPI3K inhibitor LY294002,PCR and Western Blot detected LPL expression in THP-1macrophages which were treated by diosgenin,and Western Blot detectedp-PI3K/PI3K,p-AKT/AKT and p-CREB/CREB protein level in order to investigate theeffect of diosgenin on PI3K/AKT signaling pathways.ResultsTHP-1cells were treated with160nmol/L PMA for24h incubation successfullyinduced to differentiate into THP-1macrophages. Diosgenin significantly reduced THP-1macrophage LPL expression,and the optimum concentration and time were20μmol/L and24h respectively. Moreover, diosgenin can reduce the THP-1macrophage lipidaccumulation,but which had no signifiant impact on the THP-1macrophage by LPL siRNAtreatment lipid accumulation. Furthermore, diosgenin inhibits PI3K/AKT signalingpathway, and which had no significant impact on LPL expression in THP-1macrophagesafter PI3K inhibitor LY294002treatment.ConclusionsDiosgenin can downregulate THP-1macrophage LPL expression by inhibiting thePI3K/AKT, thereby reducing the THP-1macrophage lipid accumulation.