Expression of Membrane Bound O-Acyltransferase Domain Containing 7 after Myocardial Infarction and its Role in Lipid Metabolism in vitro

Background: Previous microarray analysis on peripheral blood leukocytes from three patients with acute myocardial infarction (AMI) showed that elevated expression of membrane bound o-acyltransferase domain containing 7(MBOAT7) relative to control. To further verify these findings, we investigated more patients and explored the possible mechanisms in vitro. Objective: To study alterations in MBOAT7 expression in leukocytes after AMI, and to explore the relationship between MBOAT7 and lipid metabolism pathways in hepatocytes in vitro. Methods: Ninety patients with AMI and 90 controls were recruited from the Han population in Northeast China. RT-fluorescent PCR was used to measure MBOAT7 mRNA levels. MBOAT7 interference and overexpression vectors were constructed and transfected into L-02 hepatocytes and expression was examined by RT-qPCR and western blotting. The expression of SCAP, LDLR, HMGCR, ACAT1, ABCA1, SREBP1, ACC, FAS, SCD, and PPAR gamma in the lipid metabolism pathway were investigated by RT-qPCR. Triglyceride and cholesterol levels were measured by ELISA. Results: It was found that MBOAT7 mRNA levels were elevated in the leukocytes of patients with AMI. Hepatocytes were successfully transfected, shown by attenuated MBOAT7 mRNA levels in the silenced group (0.41 +/- 0.04 vs 1.01 +/- 0.07 for control, P=0.0019 <0.01) and raised levels in the overexpressing cells (23.29 +/- 0.39 vs 1.00 +/- 0.06 for control, P <0.0001). These results were confirmed by western blotting. Expression of the lipid metabolism-related genes was altered in response to MBOAT7 expression. Triglyceride levels increased after MBOAT7 silencing (118.40 +/- 2.26 vs 70.54 +/- 0.25 for control, P<0.0001), as did those of cholesterol (628.30 +/- 8.89 vs 544.70 +/- 11.04, P = 0.0041) but were not altered on MBOAT7 overexpression. Conclusion: MBOAT7 did not affect the metabolism of triglycerides in hepatocytes through fatty acid synthesis and decomposition pathways. The MBOAT7 level in the peripheral blood can be used as a marker for acute myocardial infarction but cannot be used as a single therapeutic target to regulate lipid metabolism.