Effects of Oxidized Low Density Lipoprotein onthe Expression and Function of ABCA1 in Macrophages

Summary:In the present study, we examined the regulation of the expression and function of ABCA1 by modified LDL (ox-LDL) in vitro. After incubation with apoA-I for 24 h, RAW264.7 cells effluxed 37.65 % cholesterol loaded by acetyl LDL (ac-LDL), and 9.78 % cholesterol in ox-LDL group. The level of ABCA1 mRNA increased about three times either when cells were incubated with 100 μg /mL ac-LDL or with 100 μg /mL ox-LDL. However, the level of ABCA1 protein rose by 1.57 times in ac-LDL group and 1.26 times in ox-LDL group. These results demonstrated that ox-LDL had different effect on the expression and function of ABCA1, ox-LDL might decrease the cholesterol efflux mediated by ABCA1 through other unknown mechanisms.

Caprylic Acid Improves Lipid Metabolism, Suppresses the Inflammatory Response and Activates the ABCA1/p-JAK2/pSTAT3 Signaling Pathway in C57BL/6J Mice and RAW264.7 Cells

Objective This study aimed to investigate the effects of caprylic acid(C8:0)on lipid metabolism and inflammation,and examine the mechanisms underlying these effects in mice and cells.Methods Fifty-six 6-week-old male C57BL/6J mice were randomly allocated to four groups fed a highfat diet(HFD)without or with 2%C8:0,palmitic acid(C16:0)or eicosapentaenoic acid(EPA).RAW246.7 cells were randomly divided into five groups:normal,lipopolysaccharide(LPS),LPS+C8:0,LPS+EPA and LPS+cAMP.The serum lipid profiles,inflammatory biomolecules,and ABCA1 and JAK2/STAT3 mRNA and protein expression were measured.Results C8:0 decreased TC and LDL-C,and increased the HDL-C/LDL-C ratio after injection of LPS.Without LPS,it decreased TC in mice(P<0.05).Moreover,C8:0 decreased the inflammatory response after LPS treatment in both mice and cells(P<0.05).Mechanistic investigations in C57BL/6J mouse aortas after injection of LPS indicated that C8:0 resulted in higher ABCA1 and JAK2/STAT3 expression than that with HFD,C16:0 and EPA,and resulted in lower TNF-α,NF-κB mRNA expression than that with HFD(P<0.05).In RAW 264.7 cells,C8:0 resulted in lower expression of pNF-κBP65 than that in the LPS group,and higher protein expression of ABCA1,p-JAK2 and p-STAT3 than that in the LPS and LPS+cAMP groups(P<0.05).Conclusion Our studies demonstrated that C8:0 may play an important role in lipid metabolism and the inflammatory response,and the mechanism may be associated with ABCA1 and the p-JAK2/p-STAT3 signaling pathway.

New insights into the regulation of cholesterol eft from the sperm membrane

Cholesterol is an essential component of the mammalian plasma membrane because it promotes membrane stability without comprising membrane fluidity. Given this important cellular role, cholesterol levels are tightly controlled at multiple levels. It has been clearly shown that cholesterol redistribution and depletion from the sperm membrane is a key part of the spermatozoon＇s preparation for fertilization. Some factors that regulate these events are described （e.g., bicarbonate, calcium） but the mechanisms underlying cholesterol export are poorly understood. How does a hydrophobic cholesterol molecule inserted in the sperm plasma membrane enter the energetically unfavorable aqueous surroundings？ This review will provide an overview of knowledge in this area and highlight our gaps in understanding. The overall aim is to better understand cholesterol redistribution in the sperm plasma membrane, its relation to the possible activation of a cholesterol transporter and the role of cholesterol acceptors. Armed with such knowledlze, sl）erm handlin~ techniques can be adapted to better prepare spermatozoa for in vitro and in vivo fertilization.

Drug resistance and combating drug resistance in cancer

Cancer is the second leading cause of death in the US.Current major treatments for cancer management include surgery,cytotoxic chemotherapy,targeted therapy,radiation therapy,endocrine therapy and immunotherapy.Despite the endeavors and achievements made in treating cancers during the past decades,resistance to classical chemotherapeutic agents and/or novel targeted drugs continues to be a major problem in cancer therapies.Drug resistance,either existing before treatment(intrinsic)or generated after therapy(acquired),is responsible for most relapses of cancer,one of the major causes of death of the disease.Heterogeneity among patients and tumors,and the versatility of cancer to circumvent therapies make drug resistance more challenging to deal with.Better understanding the mechanisms of drug resistance is required to provide guidance to future cancer treatment and achieve better outcomes.In this review,intrinsic and acquired resistance will be discussed.In addition,new discoveries in mechanisms of drug resistance will be reviewed.Particularly,we will highlight roles of ATP in drug resistance by discussing recent findings of exceptionally high levels of intratumoral extracellular ATP as well as intracellular ATP internalized from extracellular environment.The complexity of drug resistance development suggests that combinational and personalized therapies,which should take ATP into consideration,might provide better strategies and improved efficacy for fighting drug resistance in cancer.

Effect of Quercetin on Atherosclerosis Based on Expressions of ABCA1, LXR-α and PCSK9 in ApoE-/- Mice

Objective:To investigate the effect of quercetin on ATP binding cassette transporter A1(ABCA1),liver X receptor(LXR),and proprotein convertase subtilisin/kexin type 9(PCSK9)expressions in apoE-knockout(ApoE-/-)mice.Methods:The high-fat diet-induced atherosclerosis(AS)in ApoE-/-mice was established.Thirtysix mice were divided into 3 groups using random number table method:model group(n=12),quercetin group(n=12),and atorvastatin group(n=12),with C57BL/6J mice of the same strain and age as the control group(n=12).Quercetin group and atorvastatin group were administrated with quercetin and atorvastatin by oral gavage,with doses of 12.5 and 4 mg/(kg・d),respectively.Animals in the control and model groups were given an equal volume of distilled water by oral gavage once per day for a total of 12 weeks.Western blot and immunohistochemical methods were employed to determine the aortic ABCA1,LXR-a and PCSK9 protein expressi on.En zyme linked imm uno sorbent assay method was used to detect the expressi on of serum total cholesterol(TC),triglyceride(TG),high density lipoprotein-cholesterol(HDL-C),low density lipoproteincholesterol(LDL-C),tumor necrosis factor-a(TNF-a),interleukin-6(IL-6),and IL-10,combined with tissue pathological exami nation.Results:ApoE-/-mice fed with a high-fat diet had no table atherosclerosis lesions,with reduced ABCA1,LXR-a and IL-10 levels(all P<0.01),elevated PCSK9,TNF-a and IL-6 expression,and increased TC and LDL-C con tents(all P<0.01).After querceti n in terventi on,the areas of AS plaques and the expressions of PCSK9,TNF-a and IL-6 were significantly reduced(all P<0.01),while the expressions of ABCA1 and LXR-a were increased significantly(all P<0.01).Conclusion:Quercetin effectively interfered with AS development by regulating the expressions of ABCA1,LXR-a and PCSK9 in ApoE,mice.

Effect of Baizhu(Rhizoma Atractylodis Macrocephalae)extract on intestinal absorption of brucine and strychnine in vitro and in situ

OBJECTIVE:To investigate the antagonistic effect of the extract of Baizhu(Rhizoma Atractylodis Macrocephalae)(RAM)on the intestinal absorption of brucine and strychnine in Strychnos nux-vomica(NUX)and propose the mechanism of these effects.METHODS:The apparent permeability value(Papp)and absorption rate constant(Ka)were chosen as indices.The everted intestinal sac model and in situ single-pass intestinal perfusion model were used to study the effects of the RAM extract on the absorption of brucine and strychnine.To confirm the results,the brucine and strychnine concentrations in hepatic portal venous blood were determined.Western blotting was used to study P-glycoprotein(P-gp)expression in the Caco-2 cell line.RESULTS:Papp and Ka of brucine and strychnine were significantly increased in the presence of a P-gp inhibitor,but no significant increase was noted in the presence of a tight junction regulator.The RAM extract inhibited the absorption of brucine and strychnine and enhanced P-gp expression.CONCLUSION:The primary absorption mechanism for brucine and strychnine is passive transport,which is affected by P-gp.

P-glycoprotein and chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a heterogeneous definition that includes different disease states that usually are associated with abnormal inflammatory responses. Besides being prevalent, the mechanisms involved in its pathogenesis are not clear and there are few therapeutic options with tolerable side effects. P-glycoprotein (P-gp) is an efflux pump responsible of extruding xenobiotics and cellular metabolites from multiple cell types. It has been widely studied in the cancer field, due to its ability to confer resistance to chemotherapy. It also promotes Type 2 helper T-cell polarizing cytokine secretion in CRS and may represent a potential target to differentiate subtypes of CRS and personalize treatment. This state-of-the-art review explores current knowledge on the participation of P-gp in the pathogenesis of CRS, the P-gp inhibition as a novel targeted therapeutic strategy and the exosomal P-gp test, a non-invasive biomarker that can represent an important advance in the field of rhinology.

Effect of decoction of Fuzheng Jiedu Xiaoji formula(扶正解毒消积方) plus chemoembolization on primary liver cancer in patients

OBJECTIVE:To investigate the effect of the decoction of Fuzheng Jiedu Xiaoji formula(扶正解毒消积方,FJXF)plus chemoembolization(TACE)on primary liver cancer(PLC)in patients,and study the underlying mechanism.METHODS:Patients with PLC who met the inclusion criteria were randomized into case group and control group.The case group was treated with FJXF combined with TACE.The control group was treated with TACE alone.The short-term clinical effect was evaluated;liver biochemistry,liver function index and multidrug resistance-associated indicators were detected.RESULTS:FJXF combined with TACE in the case group significantly increased the disease control rate than TACE alone in the control group(83.3%vs 61.1%).There was a reduction in the serum alpha-fetoprotein at 8 weeks after treatment in each group,while no difference between the two groups.The same trend can be observed for transaminase and direct bilirubin in both groups.In the case group,it showed a significant increase for albumin at 8 weeks after treatment,while no change in the control group.Multidrug resistanceassociated indicators for multidrug resistance protein 1 and p-glycoprotein were upregulated in the case group but remained stable in the control group.CONCLUSIONS:FJXF combined TACE had a better short-term effect than TACE alone in patients with PLC.The potential mechanism was probably associated with alleviated multidrug resistance induced by FJXF.Additionally,FJXF didn’t increase the risk of liver damage in the combined therapy.