Brown adipose TRX2 deficiency activates mtDNA-NLRP3 to impair thermogenesis and protect against diet-induced insulin resistance
Yanrui Huang, … , Carlos Fernandez-Hernando, Wang Min
Yanrui Huang, … , Carlos Fernandez-Hernando, Wang Min
Published February 24, 2022
Citation Information: J Clin Invest. 2022;132(9):e148852. https://doi.org/10.1172/JCI148852.
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Research Article Inflammation Metabolism

Brown adipose TRX2 deficiency activates mtDNA-NLRP3 to impair thermogenesis and protect against diet-induced insulin resistance

Abstract

Brown adipose tissue (BAT), a crucial heat-generating organ, regulates whole-body energy metabolism by mediating thermogenesis. BAT inflammation is implicated in the pathogenesis of mitochondrial dysfunction and impaired thermogenesis. However, the link between BAT inflammation and systematic metabolism remains unclear. Herein, we use mice with BAT deficiency of thioredoxin-2 (TRX2), a protein that scavenges mitochondrial reactive oxygen species (ROS), to evaluate the impact of BAT inflammation on metabolism and thermogenesis and its underlying mechanism. Our results show that BAT-specific TRX2 ablation improves systematic metabolic performance via enhancing lipid uptake, which protects mice from diet-induced obesity, hypertriglyceridemia, and insulin resistance. TRX2 deficiency impairs adaptive thermogenesis by suppressing fatty acid oxidation. Mechanistically, loss of TRX2 induces excessive mitochondrial ROS, mitochondrial integrity disruption, and cytosolic release of mitochondrial DNA, which in turn activate aberrant innate immune responses in BAT, including the cGAS/STING and the NLRP3 inflammasome pathways. We identify NLRP3 as a key converging point, as its inhibition reverses both the thermogenesis defect and the metabolic benefits seen under nutrient overload in BAT-specific Trx2-deficient mice. In conclusion, we identify TRX2 as a critical hub integrating oxidative stress, inflammation, and lipid metabolism in BAT, uncovering an adaptive mechanism underlying the link between BAT inflammation and systematic metabolism.

Authors

Yanrui Huang, Jenny H. Zhou, Haifeng Zhang, Alberto Canfran-Duque, Abhishek K. Singh, Rachel J. Perry, Gerald I. Shulman, Carlos Fernandez-Hernando, Wang Min

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Figure 3

TRX2 loss enhances lipid uptake in BAT.

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TRX2 loss enhances lipid uptake in BAT. (A) Intestine lipid absorption c...
(A) Intestine lipid absorption capacity of 16-week-old WT and Trx2BATKO mice by detecting plasma radioactivity under oral gavage of [3H]-labeled triolein along with poloxamer 407 injection (n = 5). CPM, counts per minute. (B) Hepatic VLDL production detection by measuring plasma TG levels from WT and Trx2BATKO mice under overnight fasting and treated with LPL inhibitor poloxamer 407 to inhibit catabolism (n = 4). (C) Oral lipid tolerance test performed on mice to determine circulating TG clearance (n = 5). (D–E) Exogenous lipid uptake in tissues determined by detecting radioactivity after oral gavage of [3H]-labeled triolein of WT and Trx2BATKO mice (n = 3). Plasma radioactivity of WT and Trx2BATKO mice are shown in E. Quantitative data are presented as mean ± SEM. *P < 0.05; **P < 0.01; ***P < 0.001. Significance was assessed by 2-way ANOVA with Bonferroni’s post hoc tests (A–C) and 2-tailed Student’s t test (D and E).