Soluble Klotho protein suppresses THP-1-derived foam cell formation

AIMTo investigate the role of soluble Klotho protein in THP-1-derived foam cell formation. METHODSTHP-1 monocytes were induced into macrophages by treatment with 160 nmol/L phorbol myristate acetate for 48 h, and then were divided into 6 groups: negative control group (THP-1-derived macrophages), positive control group [THP-1-derived foam cells induced by oxidized low-density lipoprotein (ox-LDL) for 48 h], and 25, 50, 100 and 200 μg/L soluble Klotho protein groups (THP-1-derived macrophages pretreated with soluble Klotho protein at the indicat?ed concentraions for 2 h and then induced by ox-LDL for 48 h). Lipid droplets in cytoplasm were observed by oil red O staining. The cholesterol outflow rate was detected by scintillation counting technique. The content of intracellular total cholesterol, free cholesterol and cholesterol ester was detected by enzyme fluorescence analysis. The expression of acyl-coenzyme A:cholesterol acyltransferase 1 （ACAT1） and ATP-binding cassette transport?er A1 (ABCA1) at mRNA and protein levels was determined by RT-qPCR and Western blot, respectively. RESULTSOil red O staining and lipid mass quantification showed that THP-1-derived foam cell formation was dose-dependently suppressed by soluble Klotho protein. The cholesterol efflux rate of THP-1-derived foam cells was increased by soluble Klotho protein in a dose-dependent manner (P<0.05). In addition, soluble Klotho protein decreased the expression of ACAT1 and increased the expression of ABCA1 in a dose-dependent manner (P<0.05). CONCLUSION The soluble Klotho protein inhibits THP-1-derived foam cell formation in a dose-dependent manner by down-regulating the expression of ACAT1 and up-regulating the expression of ABCA1.     

Effects of sodium ferulate on cholesterol and triglyceride metabolism in atherosclerosis with hyperlipidemia

AIM:To investigate the effects of sodium ferulate on cholesterol and triglyceride metabolism in atherosclerosis with hyperlipidemia. METHODS:The rabbit model of atherosclerosis was produced by feeding high lipid forages. RAW264.7 foam cell and HepG2 injured cell models were established by incubation with oxidized low density lipoprotein (ox-LDL). The atherosclerotic plaque area was measured, and serum lipids were detected. The cellular lipid accumulation was examined by oil red O staining. The cellular contents of total cholesterol and cholesterol ester were quantified by high performance liquid chromatography. The hepatic lipase (HL) mRNA expression was determined by RT-PCR. RESULTS:(1) Compared with hyperlipid group, the aorta atherosclerosis plaque area and the serum triglyceride level were significantly decreased in sodium ferulate-treated rabbits, but the serum cholesterol level showed little change. (2) Compared with ox-LDL group, the HL mRNA expression in HepG2 cells was enhanced significantly in sodium ferulate-treated group, but the cellular contents of total cholesterol and cholesterol ester in RAW264.7 foam cells showed little change. CONCLUSION:Sodium ferulate inhibits the formation of atherosclerotic plaque in high-cholesterol-fed rabbits aorta. This antiatherosclerotic function may reduce serum triglyceride level through enhancing the expression of HL mRNA without influencing serum cholesterol level and foam cell formation.     

Effects of ghrelin on the expression of acyl coenzyme A:cholesterol acyltransferases-1 during formation of foam cells

AIM: To investigate the effects of ghrelin on the expression of acyl coenzyme A:cholesterol acyltransferases-1 (ACAT-1) during the formation of foam cells. METHODS: The human monocytic leukemia cell line THP-1 was used in the study. The differentiation of THP-1 cells into macrophages was induced by phorbol 12-myristate 13-acetate (PMA). Macrophages were incubated with oxidized LDL (ox-LDL) to generate foam cells. Ghrelin of different concentrations were used during the formation of foam cells. The ACAT-1 protein and mRNA levels were detected by Western blotting and RT-PCR. The variance of cholesterol content was measured by zymochemistry via-fluorospectrophotometer. RESULTS: Ghrelin reduced the content of cholesterol ester in foam cells obviously. ACAT-1 protein and mRNA levels were also decreased. Ghrelin reduced ACAT-1 protein mass and mRNA level in a dose-dependent manner. CONCLUSION: Ghrelin might retard the formation of atherosclerosis via down-regulating the expression of ACAT-1.     

Regulation of ghrelin on expression of ATP-binding cassette transporter A1/G1 in THP-1 derived foam cells

AIM: To investigate the regulation of ghrelin on the expression of ATP-binding cassette transporter A1 and G1 (ABCA1/ABCG1)during the foam cell formation. METHODS: The human monocytic leukemia cell line (THP-1)was chosen in our study. The differentiation of THP-1 cells into macrophages was induced by using phorbol myristate acetate (PMA). Macrophages were then incubated with oxidized LDL (ox-LDL)to generate foam cells. Ghrelin of different concentrations were treated at different time points during foam cell formation. The ABCA1/ABCG1 protein and mRNA levels were detected by Western blotting and RT-PCR. The effect of variance of cholesterol content was measured by zymochemistry via-fluorospectrophotometer. RESULTS: Ghrelin reduced the content of lipid droplet in foam cells, and increased the efflux of intracellular cholesterol significantly. Ghrelin increased ABCA1 protein mass and mRNA level in dose-dependent manner. The changes of ABCG1 protein and mRNA level were the same as ABCA1. CONCLUSION: Ghrelin interfere atherosclerosis by up-regulating the expression of ABCA1 and ABCG1.     

Effect of tea-polyphenols on the activation of NF-κB and the expression of TGF-β1 mRNA in THP-1 cells incubated with VLDL,LDL or ox-LDL

AIM:To investigate the effect of tea-polyphenols (TP) on the activation of NF-κB and the expression of TGF-β₁ mRNA in THP-1 cells (a human acute monocytic leukemia cell line). METHODS:THP-1 cells were incubated with the different concentrations of TP, VLDL, LDL or ox-LDL. In the THP-1 cellls, the nuclear malposition rate of NF-κB was detected with immunohistochemistry technique, the positive index of the TGF-β₁ mRNA expression was detected by hybridization in situ, and accumulation of total cholesterol (TC) in cells incubated with 0.4-40 μg/L TP was determined with oxidase assay. RESULTS:The nuclear malposition rate of NF-κB, the positive index of the TGF-β₁ mRNA expression and TC in THP-1 cells incubated with 0.4-40 μg/L of TP were lower than those with 0 μg/L of TP in TP-V group, TP-L group and TP-O (P＜0.05). The differences of these markers in THP-1 cells incubated with more than 40 μg/L TP in TP-V group, TP-L group and TP-O were not statistically significant, compared with TP-C group (P＞0.05). CONCLUSION:TP inhibited the activation of NF-κB, the expression of TGF-β₁ mRNA and the foam cell formation in the mono-macrophage.     

Effect of PPAR γ-ACAT1 pathway on macrophage foam cell formation induced by Chlamydia pneumoniae

AIM: To investigate the expressions of peroxisome proliferator-activated receptor γ (PPAR γ) and acyl-coenzyme A: cholesterol acyltransferase-1 (ACAT1), and to discuss the mechanisms and pathways of Chlamydia pneumoniae (C.pn)-induced macrophage foam cell formation. METHODS: THP-1-derived macrophages were incubated for 48 h with or without C.pn (1×105 to 1×106 IFU) and/or rosiglitazone (1 to 20 μmol/L), a specific PPAR γ agonist. Lipid droplets in cytoplasm were observed by oil red O staining. The contents of intracellular cholesterol ester were detected by enzyme-fluorescence. PPAR γ, ACAT1 mRNA and protein expressions were determined by RT-PCR and Western blotting, respectively. RESULTS: THP-1-derived macrophages infected with C.pn at concentration of 5×105 and 1×106 IFU resulted in the large accumulation of lipid droplets and the ratio of cholesteryl ester (CE) to total cholesterol (TC) was much higher than 50%when co-incubated with low density lipoprotein (LDL). C.pn up-regulated the expressions of ACAT1 mRNA and protein, and down-regulated the expressions of PPAR γ mRNA and protein in a concentration-dependent manner (P<0.05). Rosiglitazone (10, 20 μmol/L) markedly suppressed the accumulation of lipid droplets and CE by C.pn. Moreover, rosiglitazone inhibited the up-regulation of ACAT1 mRNA and protein expression by C.pn infection in a concentration-dependent manner (P<0.05). CONCLUSION: C.pn induces macrophage foam cell formation by up-regulating ACAT1 expression via PPARγ pathway, which may provide new evidences for the development and progression of atherosclerosis initiated by C.pn infection.     

Inhibitory effect of Wendan decoction on formation of foam cells induced by ox-LDL

AIM To explore the anti-atherosclerotic mechanism of Wendan decoction based on formation of foam cells. METHODS The optimal concentrations of Wendan decoction without cytotoxity to cells were selected by MTT assay. After Wendan decoction treatment， the formation of foam cells was examined by oil red O staining. The cholesterol efflux， cholesterol level， free cholesterol level and cholesterol esterification rate were analyzed using cholesterol efflux assay， total cholesterol assay and free cholesterol assay. The expression levels of macrophage membrane proteins， including CD36， scavenger receptor class A （SR-A）， ATP-binding cassette transporter A1 （ABCA1） and scavenger receptor class B type I （SR-BI）， were quantified by Western blot. RESULTS The optimal concentrations of Wendan decoction without cytotoxity to the cells were 0~6 g/L. Wendan decoction at the concentrations of 1.5， 3 and 6 g/L were selected for the experiments. Wendan decoction at these concentrations inhibited the formation of foam cells induced by oxidized low-density lipoprotein （ox-LDL）， and reduced the accumulation of intracellular lipids in a concentration-dependent manner （P<0.05 or P<0.01）. Wendan decoction also reduced intracellular total cholesterol level， cholesterol ester level and cholesterol esterification rate （P<0.05 or P<0.01）， promoted efflux of intracellular cholesterol （P<0.01）， and decreased the protein level of CD36 in THP-1 cell-derived macrophages （P<0.01） in a concentration-dependent manner. Wendan decoction at the concentration of 6 g/L significantly reduced the protein level of SR-A in THP-1 cell-derived macrophages （P<0.05）. At the concentrations of 3 and 6 g/L， Wendan decoction significantly increased the protein levels of ABCA1 and SR-BI in THP-1 cell-derived macrophages （P<0.05 or P<0.01）. CONCLUSION Wendan decoction significantly inhibits ox-LDL-induced formation of foam cells by reducing cholesterol deposition and promoting cholesterol efflux， and its mechanism may be related to the down-regulation of CD36 and SR-A and the up-regulation of ABCA1 and SR-BI.     

Effect of miRNA-33 on ABCA1/ABCG1 expression in RAW264.7 macrophage-derived foam cells after Hcy treatment

AIM:To study whether homocysteine (Hcy) inhibits the expression of ATP-binding cassette transporter A1 (ABCA1) and ATP-binding cassette transporter G1 (ABCG1) by microRNA-33 (miRNA-33) signaling, and reduces the efficiency of reverse cholesterol transport (RCT).METHODS:RAW264.7 macrophages were induced by oxidized low-density lipoprotein (ox-LDL) to establish foam cell model. Oil red O staining was used to determine whether the model was established successfully. miRNA-33 mimics and miRNA-33 inhibitor were transfected into the cells by Lipofectamine 2000, and the cells were exposed to Hcy at concentration of 5 mmol/L for 24 h. The intracellular lipid droplets were observed by Oil red O staining. The expression of ABCA1 and ABCG1 at mRNA and protein levels was determined by real-time PCR and Western blot. The cellular cholesterol content was analyzed by HPLC, and effluent rate of cholesterol was detected by the method of liquid scintillation counting.RESULTS:Compared with blank control group, the lipid content in miRNA-33 mimics group was increased, and the expression of ABCA1 and ABCG1 at mRNA and protein levels was decreased (P<0.05). The intracellular cholesterol content was increased gradually (P<0.05), and the cellular cholesterol efflux rate was gradually decreased (P<0.05) in miRNA-33 mimics group. Compared with blank control group, the testing results in miRNA-33 inhibitor group were the opposition of those in miRNA-33 mimics group (P<0.05). No diffe-rence of the above indexes among blank control group, miRNA-33 mimics-NC group and miRNA-33 inhibitor-NC group was observed.CONCLUSION:Hcy inhibits the mRNA and protein expression of ABCA1 and ABCG1 through miRNA-33 signaling, and reduces the efficiency of RCT in RAW264.7 macrophage-derived foam cells.     

Effect of insulin on the secretion of VEGF and its receptor in serum-free cultured bovine thoracic aortic endothelial cells

AIM: This study was designed to investigate the secretion of VEGF and its receptor (flt-1 or flk-1/KDR) protein by cultured bovine thoracic aortic endothelial cells treated with various insulin concentrations. METHODS: Endothelial cells was isolated from bovine thoracic aorta, and cultured in serum-free medium, then incubated with different insulin concentrations (30 mU/L, 300 mU/L, 3 000 mU/L). The level of VEGF and its receptor (flt-1 or flk-1/KDR) protein were detected by immunohistochemical staining. RESULTS: As compared with no insulin group, the expression of VEGF protein in low insulin concentration (30 mU/L and 300 mU/L) groups were significantly increased (P＜0.01). The expression of VEGF protein in high insulin concentration (3 000 mU/L) group was significantly decreased (P＜0.05). Howerer, no difference of the expression of VEGF receptor (flt-1 or flk-1/KDR) protein among all groups (P＞0.05) was observed. CONCLUSION: Low concentration insulin up-regulates the VEGF protein expression while high concentration insulin down-regulates the VEGF protein expression in bovine thoracic aortic endothelial cells, but insulin had no directly effect on the VEGF receptor (flt-1 or flk-1/KDR) protein expression in bovine thoracic aortic endothelial cells.     

Angiotensin-(1-7) increases expression of ABCA1 and decreases content of cholesterol in THP-1-derived foam cells via AC-cAMP pathway

AIM: To establish the THP-1-derived foam cell formation and to evaluate the effects of angiotensin-(1-7) and MDL (an inhibitor of adenylate cyclase) on the expression of ATP-binding cassete transporter A1(ABCA1) and the content of cholesterol. METHODS: THP-1-derived macrophages were treated with oxidized low-density lipoprotein(ox-LDL) to develop into foam cells. The foam cells were divided into 4 groups: control group, MDL group, Ang-(1-7) group and MDL+Ang-(1-7) group. At 24 h after treatment, the content of cAMP was measured by ELISA. The mRNA and protein levels of ABCA1 were determined by real-time RT-PCR and Western blotting, respectively. The content of cholesterol was detected by high performance liquid chromatography. RESULTS: The cAMP, the mRNA and protein levels of ABCA1 in Ang-(1-7) group were significantly higher, and the content of cholesterol was significantly lower than those in control group (P<0.05). On the contrary, the cAMP, the mRNA and protein levels of ABCA1 in MDL group were significantly lower and the content of cholesterol was significantly higher than those in control group (P<0.05). The results in MDL+Ang-(1-7) group were between Ang-(1-7) group and control group. CONCLUSION: Ang-(1-7) inhibits the formation of foam cells by promoting the expression of ABCA1 and decreasing the content of cholesterol. MDL partly antagonizes the effect of Ang-(1-7) by inhibiting the adenylate cyclase and decreasing the content of cAMP.     

Effect of pioglitazone on pre-adipocytes differentiation and GILZ expression

AIM: To investigate the roles of pioglitazone on differentiation and expression of GILZ in 3T3-L1 pre-adipocytes. METHODS: The morphological changes during 3T3-L1 cell differentiation were observed. The cells were treated with pioglitazone at concentrations of 1×10^-4～1×10^-2 mmol/L for 48 h, then the relative content of triglyceride were analyzed by oil red O staining at 2nd, 4th and 6th day during adipogenesis. The mRNA expression of peroxisome proliferator-activated receptor γ2 (PPARγ2) and lipoprotein lipase (LPL) was measured by real-time PCR. GILZ protein expression was determined by Western blot after the cells were treated with pioglitazone at concentrations of 1×10^-4 ～1×10^-2 mmol/L for 48 h.RESULTS: Oil-red O staining showed that the relative contents of triglyceride in adipocytes were increased with the increase in the pioglitazone concentration. Compared with the control, the relative contents of triglyceride in group 1×10^-3 mmol/L and group 1×10^-2 mmol/L were significantly increased (P < 0.05). The mRNA expression of PPARγ2 and LPL was also increased with the increase in the pioglitazone concentration. When pioglitazone concentration was more than 1×10^-3 mmol/L, compared with the control, the mRNA expression of PPARγ2 and LPL significantly increased (P < 0.01). The protein expression of GILZ was decreased with the increase in the pioglitazone concentration.CONCLUSION: Pioglitazone down-regulates GILZ expression, and up-regulate PPARγ2 expression and the downstream functional factor such as LPL.     

Action of ATP binding cassette transporter A 1 on cholesterol efflux in THP-1 macrophage-derived foam cells

AIM:To study the action of ATP binding cassette transporter(ABC) A 1 on cholesterol efflux in THP-1 macrophage-derived foam cells.METHODS:After exposure of the cultured THP-1 macrophage-derived foam cells to 22(R)-hydroxycholesterol and 4, 4'-diisothiocyanostilbene-2, 2'-disulfonic acid (DIDS) at different concentration for 24 hours, cholesterol efflux and ABCA1 mRNA level were determined by FJ-2107P type liquid scintillator and reverse trancriptase-polymerase chaim reaction(RT-PCR), respectively.RESULTS:Oxidized LDL promoted cholesterol efflux in THP-1 macrophages and 22(R)-hydroxycholesterol increased cholesterol efflux in THP-1 macrophage-derived foam cells in a dose-dependent manner and DIDS inhibited cholesterol efflux in THP-1 macrophage-derived foam cells in a dose-dependent manner. Exposure of the cultured THP-1 macrophage-derived foam cells to 22(R)-hydroxycholesterol and DIDS at different concentration for 24 hours, resulted in increase and decrease in the expression of ABCA1 mRNA in THP-1 macrophage-derived foam cells in a dose-dependent manner, respectively.CONCLUSION:ABCA1 playes an important role in cholesterol efflux in THP-1 macrophage-derived foam cells.     

Effect of promoting cellular cholesterol efflux on the apoptosis of foam cells derived from monocytes

AIM: To determine the effect of promoting cellular cholesterol efflux on the apoptosis of foam cells derived from monocytes. METHODS: RAW264.7 cells were incubated with 50 mg/L ox-LDL as a foam cell mode. The apoptosis rate of RAW264.7 cells was assayed by flow cytometry. Cellular lipid droplet was assayed by oil red staining. The rate of cellular cholesterol efflux was assayed with ［3H］ label cholesterol, and the content of cellular cholesterol were assayed by high performance liquid chromatography. RESULTS: After incubation with 50 mg/L ox-LDL for 48 h, the content of cellular cholesterol ester increased from (6.8±3.6) mg/g to (101.7±4.5) mg/g (P<0.05), but the rate of cholesterol efflux was only (5.2±2.1)%, and the apoptosis rate of RAW264.7 was increased from 8.14% to 42.6% (P<0.05). When treated with 200 mg/L HDL3 for 24 h, the rate of cellular cholesterol efflux were obviously increased, the apoptosis rate were decreased from 42.6% to 14.3% (P<0.05). Meanwhile, when treated with 10 mmol/L β-CD (a special compound for promoting cellular cholesterol efflux) for 24 h, the apoptosis rate was also decreased from 42.6% to 12.0%. CONCLUSION: HDL3 and β-CD inhibit the apoptosis of foam cells induced by oxidized LDL through promoting cellular cholesterol efflux.     

Effects of anthocyanin on cholesterol efflux from mouse peritoneal macrophage foam cells

AIM: To explore the effect of anthocyanin on cholesterol efflux and elucidate its possible molecular mechanism. METHODS: Mouse Peritoneal macrophages were loaded with 50 mg/L AcLDL to induce macrophage-derived foam cells. Cholesterol efflux from macrophage-derived foam cells induced by anthocyanin was determined by enzymatic methods. PPAR-γ mRNA and protein expression in macrophage-derived foam cells was assayed by quantitative PCR and western blotting. RESULTS: Anthocyanins had the capacity of promoting cholesterol efflux from mouse peritoneal macrophage-derived foam cells and increased PPAR-γ mRNA and protein expression. CONCLUSION: Anthocyain-induced cholesterol efflux may be related to its enhancing PPAR-γ mRNA and protein expression.     

Allicin attenuates macrophage-derived foam cell apoptosis by inhibiting caspase-12

AIM: To investigate the inhibitory effect of allicin on apoptosis and caspase-12 activation of macrophage-derived foam cells, and to elucidate the underlying molecular mechanisms. METHODS: RAW264.7 macrophages were pretreated with allicin (12.5, 25 and 50 mg/L) or 4-phenylbutyric acid (PBA, 4 mmol/L) for 1 h and then treated with oxidized low-density lipoprotein (ox-LDL, 100 mg/L) or tunicamycin (TM, 4 mg/L) for 24 h. The cell viability and apoptosis were examined by MTT assay and flow cytometry with Annexin V-FITC/PI staining, respectively. The activities of caspase-3 in the cells and lactic dehydrogenase (LDH) in the medium were measured. The protein levels of caspase-12 were determined by Western blot. The intracellular lipid accumulation was measured with oil red O staining and the content of intracellular total cholesterol was determined by enzymatic colorimetry. RESULTS: Similar to the endoplasmic reticulum stress (ERS) inhibitor PBA, allicin inhibited ox-LDL-induced injury of RAW264.7 macrophages in a concentration-dependent manner, as determined by the increased cell viability and the decreased LDH leakage, apoptosis and caspase-3 activity. The decrease in cell viability and increases in LDH leakage and apoptosis induced by TM (an ERS inducer) were also suppressed by allicin. Moreover, similar to PBA, allicin remarkably inhibited ox-LDL- or TM-induced activation of caspase-12. Furthermore, allicin remarkably attenuated ox-LDL-induced lipid accumulation in the RAW264.7 cells and foam cells formation in a concentration-dependent manner. CONCLUSION: Allicin may inhibit macrophage-derived foam cell apoptosis induced by ox-LDL, and the mechanism is partially related to suppressing the activation of caspase-12.     

Anti-atherosclerosis effect of astragaloside is related to miR-33a/ABCA1 signaling

AIM:To study whether astragaloside affects the expression of ATP binding cassette transporter A1 (ABCA1) by regulating miR-33a and promotes the outflow of cholesterol in macrophages. METHODS:In the in vivo experiments, HE staining was used to detect the pathological damage of the cross section of aorta in the mice. The expression of ABCA1 at mRNA and protein levels in mouse aorta was determined by real-time PCR and Western blot. In the in vitro experiments, THP-1 macrophage-derived foam cells were established and then treated with astragaloside-containing serum. Real-time PCR was used to detect the expression of miR-33a. The cells were randomly divided into blank serum group, astragaloside serum group and astragaloside serum+miR-33a mimic group. The expression of ABCA1 at mRNA and protein levels was determined by real-time PCR and Western blot. Oil red O staining and high-performance liquid chromatography were used to detect intracellular lipid content. The method of[³H] incorporation was used to detect intracellular cholesterol outflow. RESULTS:In vivo experiments showed that the blood vessels of the mice in astragaloside group were structurally normal, with neat arrangement, localized small calcified particles, mild lesions, small plaques, reduced foam cells and li-pid, and basically complete elastic plates, indicating that the pathological changes were significantly lighter than those in model group. Compared with model group, the expression of miR-33a in the aorta of the mice in astragaloside group was decreased and the relative expression of ABCA1 at mRNA and protein levels was increased (P<0.05). In vitro experiments showed that astragaloside significantly up-regulated the expression of ABCA1 at mRNA and protein levels, but this effect was inhibited by the transfection of miR-33 mimic without affecting the cell viability. Astragaloside reduced the lipid accumulation in the cells, but this effect was attenuated by miR-33 mimic. Astragaloside reduced intracellular cholesterol accumulation in relation to its promotion of intracellular cholesterol efflux, and the transfection of miR-33a mimic in the cells inhibited cholesterol efflux. CONCLUSION:Astragaloside inhibits the production of miR-33a to increase the expression of ABCA1 and promote the outflow of cholesterol in macrophages. This may be one of the molecular mechanisms of astragaloside in preventing atherosclerosis.     

Nuciferine promotes autophagy and reduces macrophage foaming by inhibiting PI3K/Akt/mTOR signaling pathway

AIM To investigate the effect of nuciferine （NUF) on the formation of foam cells and its possible molecular mechanism. METHODS Human monocyte-macrophage cell line THP-1 was induced by oxidized low-density lipoprotein (Ox-LDL) to establish foam cell model, and simultaneously treated with NUF at 5, 10 or 20 μmol/L. Oil red O staining was used and total cholesterol content was measured to observe the effect of NUF on foam cell formation. Autophagy flow was detected by immunofluorescence， and autophagosomes were detected by transmission electron microscopy. The protein levels of microtubule-associated protein 1 light chain 3 (LC3), P62, phosphorylated protein kinase B (p-Akt) and phosphorylated mammalian target of rapamycin (p-mTOR) were determined by Western blot. 3-Methyladenine (3-MA), an autophagy inhibitor, was used to inhibit autophagy and to observe whether NUF inhibited foam cell formation by regulating autophagy. RESULTS Compared with control group, the intracellular lipid deposition and total cholesterol content in Ox-LDL group were increased. Compared with Ox-LDL group, the intracellular lipid deposition and total cholesterol content in NUF group were decreased, while autophagy flow and number of autophagosomes were increased. The inhibitory effect of NUF on cell foaming was weakened after 3-MA treatment. Moreover, NUF decreased the protein levels of p-mTOR and p-Akt. CONCLUSION Nuciferine may promote autophagy by inhibiting phosphatidylinositol 3-kinase (PI3K)/Akt/mTOR signaling pathway, thus reducing intracellular lipid deposition and formation of foam cells.