Liver X receptor (LXR) mediates negative regulation of mouse and human Th17 differentiation
Guoliang Cui, Xia Qin, Lili Wu, Yuebo Zhang, Xiaoyan Sheng, Qiwen Yu, Hongguang Sheng, Beili Xi, Jingwu Z. Zhang, Ying Qin Zang
Guoliang Cui, Xia Qin, Lili Wu, Yuebo Zhang, Xiaoyan Sheng, Qiwen Yu, Hongguang Sheng, Beili Xi, Jingwu Z. Zhang, Ying Qin Zang
View: Text | PDF
Research Article

Liver X receptor (LXR) mediates negative regulation of mouse and human Th17 differentiation

Abstract

Th17 cells are a subset of CD4+ T cells with an important role in clearing certain bacterial and fungal pathogens. However, they have also been implicated in autoimmune diseases such as multiple sclerosis. Exposure of naive CD4+ T cells to IL-6 and TGF-β leads to Th17 cell differentiation through a process in which many proteins have been implicated. We report here that ectopic expression of liver X receptor (LXR) inhibits Th17 polarization of mouse CD4+ T cells, while LXR deficiency promotes Th17 differentiation in vitro. LXR activation in mice ameliorated disease in the experimental autoimmune encephalomyelitis (EAE) model of multiple sclerosis, whereas LXR deficiency exacerbated disease. Further analysis revealed that Srebp-1, which is encoded by an LXR target gene, mediated the suppression of Th17 differentiation by binding to the E-box element on the Il17 promoter, physically interacting with aryl hydrocarbon receptor (Ahr) and inhibiting Ahr-controlled Il17 transcription. The putative active site (PAS) domain of Ahr and the N-terminal acidic region of Srebp-1 were essential for this interaction. Additional analyses suggested that similar LXR-dependent mechanisms were operational during human Th17 differentiation in vitro. This study reports what we believe to be a novel signaling pathway underlying LXR-mediated regulation of Th17 cell differentiation and autoimmunity.

Authors

Guoliang Cui, Xia Qin, Lili Wu, Yuebo Zhang, Xiaoyan Sheng, Qiwen Yu, Hongguang Sheng, Beili Xi, Jingwu Z. Zhang, Ying Qin Zang

×

Figure 4

LXRα/β negatively regulates in vitro Th17 differentiation.

Options: View larger image (or click on image) Download as PowerPoint
LXRα/β negatively regulates in vitro Th17 differentiation. (A) Mouse nai...
(A) Mouse naive CD4+ T cells were cultured under Th17-inducing conditions with or without retroviral expression of LXRα and LXRβ for 4 days before protein isolation and Western blot analysis. Protein prepared from LXR KO CD4+ T cells was loaded as a control. (B) Cells from A were harvested for real-time PCR analysis of the Abca1 mRNA levels. **P < 0.01. Data in B are expressed as mean ± SD. (C) Naive CD4+ T cells were cultured under Th17- or Th0-inducing conditions with or without retroviral expression of LXRα and LXRβ for 4 days before IL-17 staining, with the gate set on GFP+CD4+ cells. This experiment was repeated at least 3 times with similar results. (D) Naive CD4+ T cells were cultured under Th17-inducing conditions with or without retroviral expression of LXRα/β and subjected to IL-17 staining with the gate set on GFP+CD4+ cells. LXR agonists T0901317 (2 μM) and GW3965 (10 μM) were added as indicated. This experiment was repeated at least 3 times with similar results. (E) Naive CD4+ T cells from LXR WT littermate control mice, LXRα KO, LXRβ KO, and LXRα/β KO mice were cultured under Th17-inducing conditions for 4 days in the presence of LXR agonists T0901317 (0.5 μM, 1 μM, 2 μM) and GW3965 (2.5 μM, 5 μM, 10 μM) before IL-17 and IFN-γ staining (3 mice per group). Values in C–E indicate the percentage of IL-17+ cells.