First Affiliated Hospital of Chongqing Medical University, Chongqing Key Laboratory of Ophthalmology, Chongqing Eye Institute, Chongqing, People's Republic of China.
Invest Ophthalmol Vis Sci. 2012 Sep 21;53(10):6434-41. doi: 10.1167/iovs.12-10398.
1,25-Dihydroxyvitamin D3 (VitD3) has been shown to have immunoregulatory properties in animal models. In this study, we investigated its inhibitory effect on the immune response in Behçet's disease (BD) patients and the possible mechanisms involved.
Naive CD4(+) T cells from active BD patients and normal controls were cultured under Th17 polarizing conditions in the presence or absence of VitD3, and cytokine production was determined by ELISA and flow cytometry. mRNA expression of several factors related to Th17 cell function was determined by real-time PCR. RNA interference for IFN regulatory factor 8 (IRF-8) was performed to study whether it was involved in the inhibitory effect of VitD3 on Th17 cell differentiation. The effect of VitD3-treated dendritic cells (DCs) on CD4(+) T cell response was determined by ELISA and flow cytometry.
Stimulation of naive CD4(+) T cells under Th17 polarizing conditions showed a higher Th17 cell differentiation in active BD patients. The addition of VitD3 significantly inhibited Th17 cell differentiation both in BD patients and in normal controls. The knockdown of IRF-8 by RNA interference significantly decreased the suppressive effect of VitD3 on Th17 differentiation. VitD3 was able to inhibit the gene expression of RORC, IL-17, IL-23R, CCR6, and Th1 cell differentiation, but upregulated IL-10 expression. VitD3-treated DCs significantly inhibited the Th17 and Th1 response.
The findings suggest that the inhibitory effect of VitD3 on the Th17 and Th1 response was mediated via both T cells and DCs and that the IRF-8 pathway is involved in the direct inhibition of VitD3 on Th17 cell differentiation.
1,25-二羟维生素 D3（VitD3）已在动物模型中显示出具有免疫调节特性。在这项研究中，我们研究了其对 Behçet 病（BD）患者免疫反应的抑制作用及其涉及的可能机制。
在存在或不存在 VitD3 的情况下，将来自活动期 BD 患者和正常对照者的幼稚 CD4(+) T 细胞在 Th17 极化条件下培养，并通过 ELISA 和流式细胞术测定细胞因子的产生。通过实时 PCR 测定与 Th17 细胞功能相关的几种因子的 mRNA 表达。进行 IFN 调节因子 8（IRF-8）的 RNA 干扰，以研究其是否参与 VitD3 对 Th17 细胞分化的抑制作用。通过 ELISA 和流式细胞术测定 VitD3 处理的树突状细胞（DC）对 CD4(+) T 细胞反应的影响。
在 Th17 极化条件下刺激幼稚 CD4(+) T 细胞显示出活动期 BD 患者中 Th17 细胞分化更高。VitD3 的添加显着抑制了 BD 患者和正常对照者的 Th17 细胞分化。RNA 干扰的 IRF-8 敲低显着降低了 VitD3 对 Th17 分化的抑制作用。VitD3 能够抑制 RORC、IL-17、IL-23R、CCR6 和 Th1 细胞分化的基因表达，但上调了 IL-10 表达。VitD3 处理的 DC 显着抑制了 Th17 和 Th1 反应。
这些发现表明，VitD3 对 Th17 和 Th1 反应的抑制作用是通过 T 细胞和 DC 介导的，并且 IRF-8 途径参与了 VitD3 对 Th17 细胞分化的直接抑制。
