Adenovirus-mediated Mouse Liver Sphingomyelin Synthase Sms Overexpression And Atherosclerosis Study Of The Relationship

The study was focused on the following two specific aims:1.To establish a mice model that over expression SMS using adenovirus vectors,2.Characterize the influence of SMS over-expression on atherogenesis.Adenovirus vectors carrying Sphingomyelin Synthase(SMS1 or SMS2)were constructed,amplified and purified.Intravenous injection of adenovirus into 8-week C57BL/6J mice generated an SMS over-expression model.Establish of such model was confirmed by both mRNA level examination(RT-PCR)and protein level examination(SMS activity assay).Based on the SMS over-expression model,following alterations were checked in order to establish the relationship between SMS Overexpression and atherogenesis:1.Level of plasma lipid(HDL-Cholesterol,phosphatidylcholine,SM,TG,total cholesterol)2.Level of lipid in liver(cholesterol,TG,SM)3.Plasma HDL and non-HDL concentration;4.SR-BI and ABCA1 level in liver5.HDL turnover test and AS lesionThe over-expression of SMS resulted into following changes:1.hepatic SMS1 and SMS2 mRNA levels were significantly increased,2.5- and 2.7-fold respectively;p<0.0012.hepatic SMS1 and SMS2 activity were significantly increased,2.1- and 2.3-fold respectively;p<0.001.3.Decrease the SM content and the Cholesterol content in HDL.And also increase the SM content and the Cholesterol content in non-HDL particles. HDL-SM was decreased 42%or 38%separately(p<0.05),HDL-ch was decreased 27%or 25%separately(p<0.05);non-HDL-SM increased 50%or 35%separately(p<0.05),non-HDL-ch was increased 64%or 61%separately (p<0.05).4.Apo B levels was significantly increased(p<0.01),while Apo A-I levels no change.5.Liver HDL receptor SR-BI expression level was increased 50%or 55% separately,and then enhanced the ability to uptake HDL-cholesterol ester selectively.There was no change to ABCA1 expression level.6.The SMase-induced aggregation of non-HDL lipoprotein was increased (p<0.0001).7.Plasma HDL clearance rates was increased(p<0.02).8.There was no functional difference between SMS1 and SMS2.To Conclude:1.Adenovirus-mediated SMS1 and SMS2 over-expression in mice increased lipoproteins atherogenic potential2.There were no significant functional difference between SMS1 and SMS23.SMS maybe a candidate target for the AS research or drug screening...