Effect of IL-37 on THP-1 differentiated foam cells formation

Objective:To investigate how IL-37affects macrophages foam-cell formation,and thereby investigate the mechanism of IL-37in the development of atherosclerosis.Method:THP-1cells were differentiated into macrophages using 160nMPMA for 24h.And then with ox-LDL or IL-37combine with ox-LDL,thereof in growth medium for 24hours to transform macrophages into foam cells.THP-1cells differentiated macrophages were stimulated with ox-LDL for 24h,then with 10ng/ml IL-37for another 24hours.Oil red O staining and cellular lipid measurement were used to identify macrophage foam cell formation.Real-time PCR and Western blot were carried out to explore the mechanism of IL-37-mediated suppression on THP-1-macrophages derived foam cell formation.Result:Oil Red O staining identified foam cell formation was significantly reduced in cells treated with IL-37and ox-LDL.The similar effect of IL-37was obtained when extracted oil red O and measured by a spectrophotometer.Compared with ox-LDL alone,IL-37and ox-LDL significantly reduced the lipids accumulation in macrophage foam cells in a concentration-dependent manner.Total cellular cholesterol was significantly reduced in IL-37and ox-LDL cultures relative to ox-LDL alone[(150.4±7.36)ng/mg vs(303.1±8.9)ng/mg,P0.01]. Moreover,real-time PCR and Western blot analysis showed that the expression of both CD36and SRA of macrophage foam cells treated by ox-LDL together with IL-37was significantly down-regulated,while ABCA-1up-regulated significantly.Conclusion:IL-37may inhibit THP-1differentiated macrophage foam-cell formation,which is largely caused by a down-regulated expression of scavenger receptor SRA and CD36and up-regulated expression of ABCA-1.