Aorta- and liver-generated TMAO enhances trained immunity for increased inflammation via ER stress/mitochondrial ROS/glycolysis pathways
Fatma Saaoud, … , Hong Wang, Xiaofeng Yang
Fatma Saaoud, … , Hong Wang, Xiaofeng Yang
Published November 17, 2022
Citation Information: JCI Insight. 2023;8(1):e158183. https://doi.org/10.1172/jci.insight.158183.
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Research Article Immunology Inflammation

Aorta- and liver-generated TMAO enhances trained immunity for increased inflammation via ER stress/mitochondrial ROS/glycolysis pathways

Abstract

We determined whether gut microbiota-produced trimethylamine (TMA) is oxidized into trimethylamine N-oxide (TMAO) in nonliver tissues and whether TMAO promotes inflammation via trained immunity (TI). We found that endoplasmic reticulum (ER) stress genes were coupregulated with MitoCarta genes in chronic kidney diseases (CKD); TMAO upregulated 190 genes in human aortic endothelial cells (HAECs); TMAO synthesis enzyme flavin-containing monooxygenase 3 (FMO3) was expressed in human and mouse aortas; TMAO transdifferentiated HAECs into innate immune cells; TMAO phosphorylated 12 kinases in cytosol via its receptor PERK and CREB, and integrated with PERK pathways; and PERK inhibitors suppressed TMAO-induced ICAM-1. TMAO upregulated 3 mitochondrial genes, downregulated inflammation inhibitor DARS2, and induced mitoROS, and mitoTEMPO inhibited TMAO-induced ICAM-1. β-Glucan priming, followed by TMAO restimulation, upregulated TNF-α by inducing metabolic reprogramming, and glycolysis inhibitor suppressed TMAO-induced ICAM-1. Our results have provided potentially novel insights regarding TMAO roles in inducing EC activation and innate immune transdifferentiation and inducing metabolic reprogramming and TI for enhanced vascular inflammation, and they have provided new therapeutic targets for treating cardiovascular diseases (CVD), CKD-promoted CVD, inflammation, transplantation, aging, and cancer.

Authors

Fatma Saaoud, Lu Liu, Keman Xu, Ramon Cueto, Ying Shao, Yifan Lu, Yu Sun, Nathaniel W. Snyder, Sheng Wu, Ling Yang, Yan Zhou, David L. Williams, Chuanfu Li, Laisel Martinez, Roberto I. Vazquez-Padron, Huaqing Zhao, Xiaohua Jiang, Hong Wang, Xiaofeng Yang

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Figure 6

TMAO activated the phosphorylation of 12 kinases, which were integrated with PERK pathways, and PERK inhibitor suppressed TMAO-upregulated ICAM-1.

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TMAO activated the phosphorylation of 12 kinases, which were integrated ...
(A) CKD renal specimen upregulated 40.6% and UT serum upregulated 26.6% kinomes; P < 0.05. (B) Human phosphokinase array was performed following the manufacturer’s instructions. HAECs were treated with TMAO for 24 hours. Protein was pooled from 3 wells (n = 2). TMAO activated the phosphorylation of 12 kinases. The variations of the manufacturer’s designated positive control (PC) spots between each array were used to determine the CI of nonspecific variations between samples. (C) PERK (EIF2AK3) expression in 61 CKD kidneys from the human microarray data set (Nephroseq), FC = 1.9 and P = 9.78 × 10–11. (D and E) PERK expression in different cells of the ascending aorta of HFD mice and human thoracic aorta. The data mining analyses were performed on the scRNA-Seq database of the Broad Institute of MIT and Harvard. (F) ICAM-1 expression in HAECs treated with TMAO and 2 PERK inhibitors (GSK2606414 and GSK2656157) were quantified using flow cytometry. The quantitative data of the ICAM-1+ cell in each group is presented (n = 3). The experiment was repeated 3 times. Data are represented as the mean ± SEM (t test; *P < 0.05, **P < 0.01).