MicroRNA-148a facilitates inflammatory dendritic cell differentiation and autoimmunity by targeting MAFB
Yao Meng, Jun Li, Zhizhong Ye, Zhihua Yin, Qing Sun, Zhuojun Liao, Guanhua Li, Jun Deng, Lu Liu, Yuqing Yu, Li Wu, Haibo Zhou, Nan Shen
Yao Meng, Jun Li, Zhizhong Ye, Zhihua Yin, Qing Sun, Zhuojun Liao, Guanhua Li, Jun Deng, Lu Liu, Yuqing Yu, Li Wu, Haibo Zhou, Nan Shen
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Research Article Dermatology

MicroRNA-148a facilitates inflammatory dendritic cell differentiation and autoimmunity by targeting MAFB

Abstract

Monocyte-derived DCs (moDCs) have been implicated in the pathogenesis of autoimmunity, but the molecular pathways determining the differentiation potential of these cells remain unclear. Here, we report that microRNA-148a (miR-148a) serves as a critical regulator for moDC differentiation. First, miR-148a deficiency impaired the moDC development in vitro and in vivo. A mechanism study showed that MAFB, a transcription factor that hampers moDC differentiation, was a direct target of miR-148a. In addition, a promoter study identified that miR-148a could be transcriptionally induced by PU.1, which is crucial for moDC generation. miR-148a ablation eliminated the inhibition of PU.1 on MAFB. Furthermore, we found that miR-148a increased in monocytes from patients with psoriasis, and miR-148a deficiency or intradermal injection of antagomir-148a immensely alleviated the development of psoriasis-like symptoms in a psoriasis-like mouse model. Therefore, these results identify a pivotal role for the PU.1-miR-148a-MAFB circuit in moDC differentiation and suggest a potential therapeutic avenue for autoimmunity.

Authors

Yao Meng, Jun Li, Zhizhong Ye, Zhihua Yin, Qing Sun, Zhuojun Liao, Guanhua Li, Jun Deng, Lu Liu, Yuqing Yu, Li Wu, Haibo Zhou, Nan Shen

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Figure 3

miR-148a is involved in the inhibition of MAFB expression by PU.1.

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miR-148a is involved in the inhibition of MAFB expression by PU.1. (A) ...
(A) Sequence alignment of the human and mouse miR-148a promoter (-strand) showing localization of predicted PU.1 binding site (blue). The transcriptional start sites are highlighted in red. Genomic locations for the human (GRCh38/hg18) and mouse (GRCm38/mm10) sequence intervals are provided above. (B) TaqMan qRT-PCR analysis of miR-148a expression in control (NC) or PU.1 siRNA transfected human monocytes. U6 snRNA was used as endogenous control (n = 3). (C and D) Kinetic analysis of miR-148a, PU.1 and MAFB expression during moDC differentiation. (C) mRNA levels of PU.1 and MAFB were detected by qRT-PCR and normalized to the β-ACTIN RNA level. The mRNA/β-ACTIN ratio on day 0 was set as 1. (D) Immunoblot analysis. The protein/β-ACTIN ratio on day 0 was set as 1. (E) Monocytes isolated from WT and miR-148a–/– BM cells were transfected with control (NC) or siRNA specific to PU.1 (si-PU.1), and the protein levels of MAFB were detected. The MAFB/β-ACTIN ratio in WT+NC was set as 1. (F) Luciferase reporter assay in Hela cells cotransfected with the promoter of miR-148a (148-luc) or miR-148a promoter lacking the PU.1 binding site (mut-luc), and a vector overexpressing PU.1. The firefly luciferase signal was normalized by renilla luciferase. The Firefly/Renilla ratio was set as 1 for the no promoter empty plasmid (luc) (n = 3). (G) Binding of PU.1 within the miR-148a promoter was analyzed using ChIP and qRT-PCR on human monocytes collected on day 0 or day 3 during moDC differentiation. The ets site in the CD11b promoter was set as positive control, whereas the downstream of miR-148 TSS was set as negative control (neg). Data are the mean percentage of input ± SEM (n = 3). P values compare the indicated groups using a 2-tailed unpaired t test or 1-way ANOVA with Bonferroni’s post hoc test. Data are shown as mean ± SEM (*P < 0.05, **P < 0.01, ***P < 0.001, n.s., not significant). miR-148a, microRNA-148a; moDC, monocyte-derived DC; quantitative real-time PCR, qRT-PCR.