MicroRNA-223 is a crucial mediator of PPARγ-regulated alternative macrophage activation
Wei Ying, … , Stephen Safe, Beiyan Zhou
Wei Ying, … , Stephen Safe, Beiyan Zhou
Published October 5, 2015
Citation Information: J Clin Invest. 2015;125(11):4149-4159. https://doi.org/10.1172/JCI81656.
View: Text | PDF
Research Article Immunology

MicroRNA-223 is a crucial mediator of PPARγ-regulated alternative macrophage activation

Abstract

Polarized activation of adipose tissue macrophages (ATMs) is crucial for maintaining adipose tissue function and mediating obesity-associated cardiovascular risk and metabolic abnormalities; however, the regulatory network of this key process is not well defined. Here, we identified a PPARγ/microRNA-223 (miR-223) regulatory axis that controls macrophage polarization by targeting distinct downstream genes to shift the cellular response to various stimuli. In BM-derived macrophages, PPARγ directly enhanced miR-223 expression upon exposure to Th2 stimuli. ChIP analysis, followed by enhancer reporter assays, revealed that this effect was mediated by PPARγ binding 3 PPARγ regulatory elements (PPREs) upstream of the pre–miR-223 coding region. Moreover, deletion of miR-223 impaired PPARγ-dependent macrophage alternative activation in cells cultured ex vivo and in mice fed a high-fat diet. We identified Rasa1 and Nfat5 as genuine miR-223 targets that are critical for PPARγ-dependent macrophage alternative activation, whereas the proinflammatory regulator Pknox1, which we reported previously, mediated miR-223–regulated macrophage classical activation. In summary, this study provides evidence to support the crucial role of a PPARγ/miR-223 regulatory axis in controlling macrophage polarization via distinct downstream target genes.

Authors

Wei Ying, Alexander Tseng, Richard Cheng-An Chang, Andrew Morin, Tyler Brehm, Karen Triff, Vijayalekshmi Nair, Guoqing Zhuang, Hui Song, Srikanth Kanameni, Haiqing Wang, Michael C. Golding, Fuller W. Bazer, Robert S. Chapkin, Stephen Safe, Beiyan Zhou

×

Figure 8

miR-223 controls M2 macrophage activation through modulation of multiple target genes.

Options: View larger image (or click on image) Download as PowerPoint
miR-223 controls M2 macrophage activation through modulation of multiple...
(A and B) Production of the activation-related surface marker CD69 in Mir223-KO BMDMs with knockdown or overexpression of Nfat5 and Rasa1 in the presence of LPS or IL-4 for 48 hours (n = 4). ev, Mir223-KO BMDMs transfected with empty vector; oe, overexpression of miR-223. (C and D) Expression of M2 activation–related cell-surface markers CD69 and CD86 in BMDMs after knockdown of Nfat5 or Rasa1 in the presence of pioglitazone and IL-4. WT-ev, WT BMDMs transfected with empty vector; KO-ev, Mir223-KO BMDMs transfected with empty vector. (E) Schematic model of the PPARγ/miR-223–regulatory axis in a macrophage. PPARγ acts as an enhancer to promote the expression of miR-223 through interaction with PPREs. miR-223 is required for PPARγ action in inducing M2 macrophage responses by controlling expression of the target genes Nfat5 and Rasa1. In addition, miR-223 directly suppresses Pknox1 expression, which leads to inhibition of M1 response. RXR, retinoid X receptor. Data are presented as the mean ± SEM. **P < 0.01, ***P < 0.001, and ****P < 0.0001 by 1-way ANOVA with Bonferroni’s post test.