Thymic Stromal Lymphopoietin Promotes Macrophag-Derived Foam Cells Formation

Objective: To investigate whether TSLP, which is highly expressed in vascularendothelial cell when subjected to oxidative stimulus, enhances the formation ofmacrophage-derived foam cell and the underlying mechanism.Method: THP-1cells were induced to differentiate into macrophages by incubationfor24hours with160nM/L phorbol myristate acetate (PMA, Sigma). And thenox-LDL (50ug/ml)was added without TSLP, with TSLP,or TSLPR-Ab for15minfollowed by TSLP (10ng/ml) treatment for24h. We used Oil red O staining to identifythe ratio of foam cell formation. RT-PCR and Western Blot analysis were used tostudy the mechanism of TSLP-mediated positive role in accumulation of lipid dropletsin macrophage. In addition, macrophages (2×106cells/well) were cultured indifferent doses of TSLP (0,5,10,20ng/ml) under the stimulation of ox-LDL(50ug/ml) for24hours. RT-PCR and Western Blot were carried out to analysedCD36,SRA,ABCA1gene and protein expression in a concentration-dependent probl–em.Result: Compared with the control, TSLP facilitates the macrophage-derived foamcell formation and upregulates the expression of CD36and SRA, while displays adecreased expression of ABCA1. The TSLPR-Ab-treated group has a similar rolewith the control. Different doses of TSLP (0,5,10,20ng/ml) was cultured withmacrophages in the role of ox-LDL (50ug/ml) for24hours, as the dose increasing,theexpression of CD36,SRA exhibits concentration-dependent increase. While the expr-ession of ABCA1exhibits concentration-dependent decrease.Conclusion: Our findings collectively suggest that TSLP perhaps acceleratesmacrophage foam-cell formation largely by means of TSLPR signal pathway and ismediated through the up-regulation of scavenger receptor CD36, SRA expression anddown-regulation of ABCA1expression.