Blocking fatty acid–fueled mROS production within macrophages alleviates acute gouty inflammation
Christopher J. Hall, … , Nicola Dalbeth, Philip S. Crosier
Christopher J. Hall, … , Nicola Dalbeth, Philip S. Crosier
Published March 26, 2018
Citation Information: J Clin Invest. 2018;128(5):1752-1771. https://doi.org/10.1172/JCI94584.
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Research Article Immunology Inflammation

Blocking fatty acid–fueled mROS production within macrophages alleviates acute gouty inflammation

Abstract

Gout is the most common inflammatory arthritis affecting men. Acute gouty inflammation is triggered by monosodium urate (MSU) crystal deposition in and around joints that activates macrophages into a proinflammatory state, resulting in neutrophil recruitment. A complete understanding of how MSU crystals activate macrophages in vivo has been difficult because of limitations of live imaging this process in traditional animal models. By live imaging the macrophage and neutrophil response to MSU crystals within an intact host (larval zebrafish), we reveal that macrophage activation requires mitochondrial ROS (mROS) generated through fatty acid oxidation. This mitochondrial source of ROS contributes to NF-κB–driven production of IL-1β and TNF-α, which promote neutrophil recruitment. We demonstrate the therapeutic utility of this discovery by showing that this mechanism is conserved in human macrophages and, via pharmacologic blockade, that it contributes to neutrophil recruitment in a mouse model of acute gouty inflammation. To our knowledge, this study is the first to uncover an immunometabolic mechanism of macrophage activation that operates during acute gouty inflammation. Targeting this pathway holds promise in the management of gout and, potentially, other macrophage-driven diseases.

Authors

Christopher J. Hall, Leslie E. Sanderson, Lisa M. Lawrence, Bregina Pool, Maarten van der Kroef, Elina Ashimbayeva, Denver Britto, Jacquie L. Harper, Graham J. Lieschke, Jonathan W. Astin, Kathryn E. Crosier, Nicola Dalbeth, Philip S. Crosier

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Figure 5

Irg1 contributes to MSU crystal–driven macrophage activation.

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Irg1 contributes to MSU crystal–driven macrophage activation. (A) Expres...
(A) Expression of il1b in control MO–, Irg1 SBMO1–, Irg1 gRNA–, and Cas9 plus Irg1 gRNA–injected larvae following MSU crystal injection. The numbers in parentheses indicate the frequency of larvae with the indicated phenotype. (B and C) Quantification of il1b expression, as detected in A, for Irg1 SBMO1–injected (B) and CRISPR-Cas9 F0 irg1 mutants (C). The MSU sample in C is the same as in Figure 1C (3 hpi) and Figure 4F. (D) Immunofluorescence of Tnfa in the hindbrains of control MO–, Irg1 SBMO1–, Irg1 gRNA–, and Cas9 plus Irg1 gRNA–injected Tg(mpeg1:EGFP) larvae following MSU crystal injection. The control MO-MSU image is the same as in Supplemental Figure 3E and Supplemental Figure 4F. (E and F) Quantification of Tnfa, as detected in D, for Irg1 SBMO1–injected (E) and CRISPR-Cas9 F0 irg1 mutants (F). n = 15 larvae/treatment. The control MO-MSU sample in E is the same as in Supplemental Figure 3F and Supplemental Figure 4G. The DMSO-MSU sample in F is the same as in Figure 1G (3 hpi); Figure 3D; and Supplemental Figure 5, D and H. Data were pooled from 2 independent experiments and represent the mean ± SD. ****P < 0.0001, by 1-way ANOVA with Dunnett’s post hoc test. Scale bars: 100 μm (A) and 50 μm (D).