1,25-二羟维生素D_3对其诱导的树突状细胞上Toll样受体7表达的抑制作用

Effect of 1,25-dihydroxyvitamin D_3 to inhibit dendritic cells maturation through down-regulation of Toll-like receptor 7

目的探讨Toll样受体7(TLR7)在1,25-二羟维生素D3(1,25-(OH)2D3)抑制树突状细胞(DC)成熟中可能的机制。方法体外扩增小鼠骨髓来源的DC,采用流式细胞术和混合淋巴细胞反应检测1,25-(OH)_2D_3对DC表型和功能的影响;利用RT-PCR半定量方法测定1,25-(OH)_2D_3对DC的TLR7表达的影响。结果 1,25-(OH)_2D_3处理后,DC表达CD86和MHCⅡ的荧光强度均明显降低;对T细胞的刺激能力较对照组明显减弱,差异有统计学意义(P<0.05);与对照组比较,1,25-(OH)_2D_3可以明显下调TLR7的表达(P<0.05)。结论 1,25-(OH)_2D_3可能通过影响TLR7的表达来抑制DC细胞的成熟,从而使DC具有耐受性特征。

AIM To explore the possible role of Toll-like receptor 7（TLR7） in the procedure of the inducement of immature dendritic cells（DCs） by 1,25-dihydroxyvitamin D3. METHODS DCs were harvested by differentiating mouse borrow cells in vitro. The influence of 1, 25-dihydroxyvitamin D3 on phenotype and function of DCs was determined by flow cytometry and mixed lymphocyte reactions. The expression of TLR7 on 1,25-dihydroxyvitamin D3-induced DCs was detennined by semi-quantitative reverse transcription polymerase chain reaction（RT-PCR）. RESULTS Treated by 1, 25-dihydroxyvitamin D3, DCs had significantly lower fluorescence intensity of CD80 and MHC II （ P 〈 0.05）, and DCs＇ ability to stimulate T cells was significantly lower than the control（ P 〈 0.05）. Compared to the control, 1,25-dihydrox- yvitamin D3 could obviously down-regulate the expression of TLR7 （ P 〈 0.05）. CONCLUSION 1,25-Dihydroxyvitamin D3 can inhibit the maturation of DCs, and might make DCs tolerant by influencing the expression of TLR7.