ANT2 drives proinflammatory macrophage activation in obesity
Jae-Su Moon, … , Chanond A. Nasamran, Yun Sok Lee
Jae-Su Moon, … , Chanond A. Nasamran, Yun Sok Lee
Published October 22, 2021
Citation Information: JCI Insight. 2021;6(20):e147033. https://doi.org/10.1172/jci.insight.147033.
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Research Article Endocrinology Metabolism

ANT2 drives proinflammatory macrophage activation in obesity

Abstract

Macrophage proinflammatory activation is an important etiologic component of the development of insulin resistance and metabolic dysfunction in obesity. However, the underlying mechanisms are not clearly understood. Here, we demonstrate that a mitochondrial inner membrane protein, adenine nucleotide translocase 2 (ANT2), mediates proinflammatory activation of adipose tissue macrophages (ATMs) in obesity. Ant2 expression was increased in ATMs of obese mice compared with lean mice. Myeloid-specific ANT2-knockout (ANT2-MKO) mice showed decreased adipose tissue inflammation and improved insulin sensitivity and glucose tolerance in HFD/obesity. At the molecular level, we found that ANT2 mediates free fatty acid–induced mitochondrial permeability transition, leading to increased mitochondrial reactive oxygen species production and damage. In turn, this increased HIF-1α expression and NF-κB activation, leading to proinflammatory macrophage activation. Our results provide a previously unknown mechanism for how obesity induces proinflammatory activation of macrophages with propagation of low-grade chronic inflammation (metaflammation).

Authors

Jae-Su Moon, Flavia Franco da Cunha, Jin Young Huh, Alexander Yu Andreyev, Jihyung Lee, Sushil K. Mahata, Felipe C.G. Reis, Chanond A. Nasamran, Yun Sok Lee

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Figure 7

ANT2 mediates opening of the mtPTP and increased mtROS generation during M1-like macrophage polarization.

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ANT2 mediates opening of the mtPTP and increased mtROS generation during...
(A) mtROS levels in WT and ANT2-MKO BMDMs treated with or without LPS for 30 minutes (n = 8–10 wells/group). (B) Cytosolic ROS levels in WT and ANT2-MKO BMDMs treated with or without LPS for 30 minutes (n = 10 wells/group). (C) mtROS levels in WT and ANT2-MKO BMDMs treated with or without antimycin A for 30 minutes (n = 4 wells/group). (D) Western blot analysis of inflammatory signaling pathway in WT and ANT2-MKO BMDMs treated with or without antimycin A (AA) for 30 minutes. (E) Opening of the mtPTP. WT and ANT2-MKO BMDMs were treated with LPS or PA for 10 minutes and opening of the mtPTP was measured by the calcein-cobalt method. Reduction in calcein fluorescence indicates opening of the mtPTP (n = 3 wells/group). (F) Mitochondrial membrane potential in WT and ANT2-MKO BMDMs treated with LPS or PA for 10 minutes (n = 3 wells/group). (G) Opening of the mtPTP in WT and ANT2-MKO BMDMs treated with ionomycin for 5 minutes (n = 5 wells/group). (H) mtROS levels in WT and ANT2-MKO BMDMs treated with or without PA (100 μM) or LPS (600 ng/mL) for 30 minutes in the presence or absence of CsA or TRO19622 (n = 3 wells/group). (I) mRNA expression of proinflammatory genes in WT and ANT2-MKO BMDMs treated with or without PA (100 μM) or LPS (600 ng/mL) in the presence or absence of TRO19622 (TRO) (n = 4 wells/group). (J) CS activity in WT BMDMs treated with or without PA (100 μM) or LPS (600 ng/mL) for 6 hours in the presence or absence of CsA or TRO19622 (n = 3 wells/group). Microscopic images in E–G were taken under ×20 magnification. In all panels, all values are mean ± SEM. *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001. Statistical analysis was performed by 2-way ANOVA with Tukey’s multiple comparison test.