The Regulation Effect And Mechanism Of Atorvastatin On FOXP3 Expression In CD4~+Treg Cells Of ACS Patients:Key Role Of RXRα

Aims:To explore the effect and mechanism of atorvastatin on the expression of FOXP3 in CD4⁺Treg cells in patients with acute coronary syndrome（ACS）,and to reveal the role of RXRαin the regulation of this process.Methods:Clinical suspected acute coronary syndrome inpatients were enrolled（04/2016--12/2017）.All patients received coronary angiography（CAG）.According to the2014AHA/ACC guideline for the management of patients with ACS,the patients were divided into two groups:ACS group and control group.（1）CD4⁺T were extracted from peripheral blood by human CD4⁺T cell enrichment cocktail,the purity of CD4⁺T cells and the percentage of CD4⁺FOXP3⁺Treg cells in CD4⁺T were determined by flow cytometry.（2）extract CD4⁺T cells from peripheral blood,CD3（5ug/ml）/CD28（2ug/ml）stimulation,TGFβ1（5ng/ml）and（or）atorvastatin(10^-7M-10^-8M)﹑RXRαinhibitor UVI3003(10^-6M-10^-7M)﹑RXRαagonists 9-cis-RA(10^-7M-10^-9M)intervention,the percentage of CD4⁺FOXP3⁺Treg cells in CD4⁺T was determined by flow cytometry,the levels of FOXP3protein and Smad2/p-Smad2 protein was measured by Western blot,the levels of IL-10mRNA were detected by real-time PCR,serum levels of IL-10 were detected by ELISA.Results:（1）Compared with control group,the proportion of CD4⁺FOXP3⁺Treg cells and the levels of FOXP3 were significantly reduced in ACS group（P<0.05）;（2）In the ACS patients,the proportion of CD4⁺FOXP3⁺Treg cells and the levels of FOXP3 in atorvastatin(10^-7M)combined with TGFβ1（5ng/ml）group were significantly higher than TGFβ1（5ng/ml）group（P<0.05）.（3）In the ACS patients,the levels of p-Smad2 in atorvastatin(10^-7M)combined with TGFβ1（5ng/ml）group were significantly higher than TGFβ1（5ng/ml）group（P<0.05）,but there was no significant difference in the levels of total Smad2 among the groups...After the pretreatment of CD4⁺T cells with Smad2 inhibitor(10^-7M),the effect of atorvastatin（10-7M）combined with TGFβ1（5ng/ml）intervention on FOXP3 expression was significantly inhibited（P<0.05）.（4）In the ACS patients,the proportion of CD4⁺FOXP3⁺Treg cells and the levels of FOXP3 in 9-cis-RA(10^-8M)combined with TGFβ1（5ng/ml）group were significantly higher than TGFβ1（5ng/ml）group（P<0.05）.When RXRαwas suppressed,the levels of p-Smad2 in atorvastatin(10^-7M)combined with TGFβ1（5ng/ml）group was significant reduced（P<0.05）,but there was no significant difference in the levels of total Smad2（6）In the ACS patients,the levels of IL-10mRNA and IL-10 in atorvastatin(10^-7M)combined with TGFβ1（5ng/ml）group and 9-cis-RA(10^-8M)combined with TGFβ1（5ng/ml）group were significantly higher than TGFβ1（5ng/ml）group（P<0.05）.When RXRαwas suppressed,the levels of IL-10mRNA and IL-10 in atorvastatin(10^-7M)combined with TGFβ1（5ng/ml）group was significant reduced.Conclusion:Atorvastatin promotes the expression of FOXP3 and the synthesis and secretion of IL-10 cytokine in CD4⁺Treg cells of ACS patients by activating the Smad2pathway,and nuclear receptor RXRαplays an important mediating role in this process..