sPLA2-IIA Augments Oxidized LDL-Induced MCP-1 Expression in Vitro Through Activation of Akt.
OBJECTIVE
Group IIA secretory phospholipase A2 (sPLA2-IIA) has an important role in atherosclerosis. In this study, we explored whether sPLA2-IIA overexpression could promote atherosclerosis in normal environment alone or with other inflammatory factors.


METHODS
Human aortic smooth muscle cells (HASMCs) were transduced with Lv-GFP-sPLA2-IIA, a plasmid containing sPLA2-IIA coupled with green fluorescent protein (GFP). Cells were incubated in the presence or absence of oxidized low-density lipoprotein (LDL), sPLA2 inhibitor LY315920 or PI3K/Akt inhibitor LY294002. The mRNA expression and protein secretion of monocyte chemoattractant protein-1 (MCP-1) were assessed by quantitative real-time polymerase chain reaction (QRT-PCR) and enzyme-linked immunosorbent assay (ELISA), respectively. Phosphorylation of Akt was examined by western blotting.


RESULTS
Lv-GFP-sPLA2-IIA-transduced HASMCs remained fluorescent during 72 h of the study period with infection ratio of around 80%. The mRNA expression and protein secretion of MCP-1 was not altered in groups of HASMCs, Lv-GFP transduced and Lv-GFP-sPLA2-IIA-transduced HASMCs (p>0.05), but was significantly increased in the presence of oxidized LDL especially in Lv-GFP-sPLA2-IIA transduction group (p<0.01). However, with the addition of LY315920, this enhancement was notably decreased (p<0.05). This enhancement was also markedly abolished by co-incubation with LY294002, paralleled with suppressed Akt phosphorylation.


CONCLUSIONS
Overexpression of sPLA2-IIA does not alter MCP-1 level at baseline, but could enhance the atherogenic effect of oxidized LDL in HASMCs, at least partly due to activation of Akt. These findings may provide a strategy for treatment of inflammatory cardiovascular diseases.
Yongjun
Y
Guo
Bo
B
Li
Xuejing
X
Xu
Rong
R
Wu
Weihua
W
Li
D000085:Acetates / Q000494:pharmacology; D002460:Cell Line; D018932:Chemokine CCL2 / Q000378:metabolism*; D002867:Chromones / Q000494:pharmacology; D004797:Enzyme-Linked Immunosorbent Assay; D015870:Gene Expression / Q000187:drug effects; D017930:Genes, Reporter; D054501:Group II Phospholipases A2 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D057809:HEK293 Cells; D006801:Humans; D007211:Indoles / Q000494:pharmacology; D007651:Keto Acids; D008077:Lipoproteins, LDL / Q000633:toxicity*; D009025:Morpholines / Q000494:pharmacology; D032389:Myocytes, Smooth Muscle / Q000166:cytology / Q000378:metabolism; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation; D051057:Proto-Oncogene Proteins c-akt / Q000037:antagonists & inhibitors / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism
D000085:Acetates; D018932:Chemokine CCL2; D002867:Chromones; D054501:Group II Phospholipases A2; D007211:Indoles; D007651:Keto Acids; D008077:Lipoproteins, LDL; D009025:Morpholines; D019869:Phosphatidylinositol 3-Kinases; D000081082:Phosphoinositide-3 Kinase Inhibitors; D051057:Proto-Oncogene Proteins c-akt; D012333:RNA, Messenger; C111835:CCL2 protein, human; C099252:oxidized low density lipoprotein; C545088:varespladib methyl; C085911:2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one