BACKGROUNDLipoprotein-associated phospholipase A2 (Lp-PLA2) is mainly secreted by macrophages, serving as a specific marker of atherosclerotic plaque and exerting pro-atherogenic effects. It is known that high-density lipoprotein (HDL) plays an important role against atherosclerosis by inhibiting pro-inflammatory factors, however, the relationship between HDL and Lp-PLA2 remains elusive.

METHODSIn this study, reverse transcription-polymerase chain reaction (RT-PCR), Western blotting, and a platelet-activating factor (PAF) acetylhydrolase assay were performed to determine the Lp-PLA2 mRNA level, protein expression and activity in human monocyte-derived macrophages upon HDL treatment of different concentrations and durations. To investigate the underlying mechanism of HDL-induced Lp-PLA2 action, pioglitazone, a peroxisome proliferator-activated receptor-γ (PPARγ) ligand, was introduced to human monocyte-derived macrophages and mRNA and protein levels of Lp-PLA2, as well as its activity, were determined.

RESULTSLp-PLA2 mRNA levels, protein expression and activity were significantly inhibited in response to HDL treatment in a dose and time dependent manner in human monocyte-derived macrophages. Pioglitazone treatment (1 - 10 ng/ml) upregulated the Lp-PLA2 mRNA level, protein expression and activity in human monocyte-derived macrophages, while the effects were markedly reversed by HDL. In addition, pioglitazone resulted in a significant increase in PPARγ phosphorylation in human monocyte-derived macrophages, which could be inhibited by HDL.

CONCLUSIONThese findings indicate that HDL suppresses the expression and activity of Lp-PLA2 in human monocyte-derived macrophages, and the underlying mechanisms may be mediated through the PPARγ pathway.

1-Alkyl-2-acetylglycerophosphocholine Esterase ; genetics ; metabolism ; Cells, Cultured ; Humans ; Lipoproteins, HDL ; pharmacology ; Macrophages ; drug effects ; enzymology ; metabolism ; PPAR gamma ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Signal Transduction ; drug effects ; genetics

OBJECTIVETo investigate the effect of corticosterone on the expression of the neuronal migration protein lissencephaly 1 (LIS1) in developing cerebral cortical neurons of fetal rats.

METHODSThe primary cultured cerebral cortical neurons of fetal Wistar rats were divided into control group, low-dose group, and high-dose group. The neurons were exposed to the medium containing different concentrations of corticosterone (0 μmol/L for the control group, 0.1 μmol/L for the low-dose group, and 1.0 μmol/L for the high-dose group). The neurons were collected at 1, 4, and 7 days after intervention. Western blot and immunocytochemical staining were used to observe the change in LIS1 expression in neurons.

RESULTSWestern blot showed that at 7 days after intervention, the low- and high-dose groups had significantly higher expression of LIS1 in the cytoplasm and nucleus of cerebral cortical neurons than the control group (P<0.05), and the high-dose group had significantly lower expression of LIS1 in the cytoplasm of cerebral cortical neurons than the low-dose group (P<0.05). Immunocytochemical staining showed that at 1, 4, and 7 days after corticosterone intervention, the high-dose group had a significantly lower mean optical density of LIS1 than the control group and the low-dose group (P<0.05). At 7 days after intervention, the low-dose group had a significantly lower mean optical density of LIS1 than the control group (P<0.05).

CONCLUSIONSCorticosterone downregulates the expression of the neuronal migration protein LIS1 in developing cerebral cortical neurons of fetal rats cultured in vitro, and such effect depends on the concentration of corticosterone and duration of corticosterone intervention.

1-Alkyl-2-acetylglycerophosphocholine Esterase ; analysis ; genetics ; Animals ; Cells, Cultured ; Cerebral Cortex ; drug effects ; metabolism ; Corticosterone ; pharmacology ; Dose-Response Relationship, Drug ; Female ; Fetus ; drug effects ; Microtubule-Associated Proteins ; analysis ; genetics ; Pregnancy ; Rats ; Rats, Wistar

OBJECTIVETo investigate the effects of simvastatin on lipopolysaccharides (LPS) induced upregulation of Lp-PLA(2) in human peripheral blood monocytes-macrophages and the related mechanisms.

METHODSPeripheral blood monocytes of healthy volunteer were isolated and incubated for 2-3 days. Monocytes were incubated with various concentrations of LPS for 6 h or with 1 µg/ml of LPS for different times in LPS group. In simvastatin group and MAPK inhibitors groups, cells were pre-treated with simvastatin (10(-2) - 10(-7) mmol/L) or various MAPK inhibitors (10 µmol/L SB203580, 20 µmol/L U0126, and 20 µmol/L SP600125) before LPS co-incubation. Lp-PLA(2) activity was measured by chronometry, Lp-PLA(2) mRNA expression was detected by RT-PCR. Protein expressions of Lp-PLA(2) and p38MAPK and phosphorylated p38MAPK were examined by Western blot.

RESULTS(1) LPS significantly upregulated Lp-PLA(2) mRNA and protein expression, as well as the enzyme activity in a time and concentration dependent manner, which could be significantly attenuated by simvastatin in a time and concentration dependent manner. (2) Simvastatin significantly reduced LPS-induced p38MAPK phosphorylation. The p38 MAPK inhibitor SB203580, but not MEK1/2 inhibitor U0126 and JNK inhibitor SP600125, completely prevented LPS-mediated up-regulation of Lp-PLA(2) at protein level.

CONCLUSIONThis study demonstrated that LPS significantly upregulated Lp-PLA(2) mRNA and protein expression, as well as the enzyme activity in a time and concentration dependent manner via Rho-p38MAPK pathway, which could be significantly suppressed by simvastatin.

1-Alkyl-2-acetylglycerophosphocholine Esterase ; Anthracenes ; pharmacology ; Butadienes ; pharmacology ; Cells, Cultured ; Humans ; Imidazoles ; pharmacology ; Lipopolysaccharides ; pharmacology ; Macrophages ; drug effects ; metabolism ; Monocytes ; drug effects ; metabolism ; Nitriles ; pharmacology ; Phospholipases A2 ; metabolism ; Phosphorylation ; Pyridines ; pharmacology ; RNA, Messenger ; genetics ; Simvastatin ; pharmacology ; p38 Mitogen-Activated Protein Kinases ; metabolism

OBJECTIVETo observe the effects of Danlou Tablet (DT) on inflammatory reaction, and expressions of lipoprotein-associated phospholipase A2 (LP-PLA2), secretory phospholipase A2 (sPLA2), and to analyze potential mechanisms.

METHODSForty male Wistar rats were randomly and equally divided into five groups, i.e., the normal control group, the model group, the Western medicine (WM) group, the low dose DT group, the high dose DT group, 8 in each group. Rats in the normal control group were fed with basic forage for 12 successive weeks, while AS rat model was established in rats of the other four groups by feeding high fat and sugar forage plus intraperitoneal injection of vitamin D₃. Normal saline, atorvastatin calcium suspension (at the daily dose of 1.8 mg/kg), low dose DT suspension (at the daily dose of 450 mg/kg), and high dose DT suspension (at the daily dose of 900 mg/kg) were administered to rats in the model group, the WM group, the low dose DT group, the high dose DT group respectively by gastragavage for 8 successive weeks. The general condition of all rats was observed. Rats were sacrificed after gastric administration and their serum collected. Serum levels of lipids (TC, TG, HDL-C, LDL-C) and inflammatory factors [IL-6, TNF-α, monocyte chemoattractant protein 1 (MCP-1), oxidized low-density lipoprotein (ox-LDL), lipoprotein-associated phospholipase A2 (LP-PLA2), secretory phospholipase A2 (sPLA2)] were detected. Pathological changes of thoracic aorta were observed by HE staining. Protein and gene expressions of LP-PLA2 and sPLA2 in thoracic aorta were measured by Western blot and real-time fluorescent quantitative PCR respectively.

RESULTSCompared with the normal control group, rats in the model group were in low spirits and responded poorly. Typical atherosclerotic plaque could be seen in thoracic aorta of rats in the model group. Serum levels of TC, TG, LDL-C, IL-6, TNF-α, MCP-1, ox-LDL, LP-PLA2, and sPLA2 significantly increased (P < 0.05); protein and gene expressions of LP-PLA2 and sPLA2 in rat thoracic aorta increased (P < 0.05) in the model group. After 8 weeks of intervention, rats in 3 medication groups appeared active, and HE staining showed subsidence of plaque in rat thoracic aorta. Compared with the model group, serum levels of TC, TG, LDL-C, IL-6, TNF-α, MCP-1, ox-LDL, and LP-PLA2 decreased in 3 medication groups (P < 0.01, P < 0.05); serum sPLA2 level decreased, protein and mRNA expressions of LP-PLA2 and sPLA2 in rat thoracic aorta decreased in the WM group (P < 0.01, P < 0.05); protein and mRNA expressions of LP-PLA2 in rat thoracic aorta significantly decreased in the low dose DT group (P < 0.01, P < 0.05), and those of LP-PLA2 and sPLA2 decreased in the high dose DT group (P < 0.01, P < 0.05).

CONCLUSIONDT could fight against inflammatory reaction and AS possibly through inhibiting LP-PLA2 expression and reducing ox-LDL production.

1-Alkyl-2-acetylglycerophosphocholine Esterase ; blood ; Animals ; Aorta, Thoracic ; pathology ; Atherosclerosis ; drug therapy ; Chemokine CCL2 ; blood ; Drugs, Chinese Herbal ; pharmacology ; Inflammation ; drug therapy ; Interleukin-6 ; blood ; Lipids ; blood ; Lipoproteins, LDL ; blood ; Male ; Phospholipases A2 ; blood ; Plaque, Atherosclerotic ; Random Allocation ; Rats ; Rats, Wistar ; Tablets ; Tumor Necrosis Factor-alpha ; blood

OBJECTIVE: To detect the changes of leukotriene E4(LTE4), prostaglandin D2(PGD2), carboxypeptidase A3(CPA3) and platelet activating factor (PAF) in guinea pigs died from anaphylactic shock. METHODS: Guinea pigs were used for establishing anaphylactic shock models. The levels of LTE4, PGD2 and CPA3, and PAF were detected in urine, plasma, and brain tissues with ELISA kit, respectively. The significant biomarkers were selected comparing with control group. The changes of PGD2, CPA3 and PAF in the guinea pigs at time zero, 12 and 24 hours after death were observed and compared respectively. The effect of platelet activating factor acetylhydrolase (PAF-AH) to PAF in guinea pig brain was examined and compared. RESULTS: There were no statistically differences of LTE4 levels in urine observed between experimental group and control group. The levels of CPA3, PGD2 and PAF in the experimental group were significantly higher than that in the control group at 0 h. The levels of PAF at 12 and 24 hours after anaphylactic shock were significantly higher than that in the control group. The levels of PAF decreased significantly after pretreatment with PAF-AH. CONCLUSION LTE4 in urine cannot be selected as a biomarker to determine the anaphylactic shock. PGD2 and CPA3 in plasma, and PAF in brain tissue may be used as biomarkers to determine the anaphylactic shock. PAF-AH may be potentially useful for clinical treatment of anaphylactic shock.
1-Alkyl-2-acetylglycerophosphocholine Esterase/pharmacology* ; Anaphylaxis/prevention & control* ; Animals ; Brain/pathology* ; Carboxypeptidases/blood* ; Case-Control Studies ; Disease Models, Animal ; Egg Proteins/administration & dosage* ; Enzyme-Linked Immunosorbent Assay ; Female ; Guinea Pigs ; Leukotriene E4/urine* ; Male ; Mice ; Platelet Activating Factor/metabolism* ; Prostaglandin D2/blood* ; Time Factors