1. Academic Validation
  2. Pyruvate Dehydrogenase Kinase Is a Metabolic Checkpoint for Polarization of Macrophages to the M1 Phenotype

Pyruvate Dehydrogenase Kinase Is a Metabolic Checkpoint for Polarization of Macrophages to the M1 Phenotype

  • Front Immunol. 2019 May 7;10:944. doi: 10.3389/fimmu.2019.00944.
Byong-Keol Min 1 2 Sungmi Park 3 Hyeon-Ji Kang 2 Dong Wook Kim 3 Hye Jin Ham 3 Chae-Myeong Ha 1 Byung-Jun Choi 1 Jung Yi Lee 3 Chang Joo Oh 2 Eun Kyung Yoo 3 Hui Eon Kim 3 Byung-Gyu Kim 3 Jae-Han Jeon 4 Do Young Hyeon 5 Daehee Hwang 5 6 Yong-Hoon Kim 7 Chul-Ho Lee 7 Taeho Lee 8 Jung-Whan Kim 9 Yeon-Kyung Choi 4 Keun-Gyu Park 4 Ajay Chawla 10 Jongsoon Lee 11 Robert A Harris 12 In-Kyu Lee 1 2 3 4
Affiliations

Affiliations

  • 1 BK21 Plus KNU Biomedical Convergence Programs, Department of Biomedical Science, Kyungpook National University, Daegu, South Korea.
  • 2 Research Institute of Aging and Metabolism, Kyungpook National University, Daegu, South Korea.
  • 3 Leading-Edge Research Center for Drug Discovery and Development for Diabetes and Metabolic Disease, Kyungpook National University Hospital, Daegu, South Korea.
  • 4 Department of Internal Medicine, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu, South Korea.
  • 5 Department of Biological Sciences, Seoul National University, Seoul, South Korea.
  • 6 Center for Plant Aging Research, Institute for Basic Science, Daegu Gyeongbuk Institute of Science and Technology, Daegu, South Korea.
  • 7 Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon, South Korea.
  • 8 College of Pharmacy, Kyungpook National University, Daegu, South Korea.
  • 9 Department of Biological Sciences, The University of Texas at Dallas, Richardson, TX, United States.
  • 10 Department of Medicine, University of California, San Francisco, San Francisco, CA, United States.
  • 11 Soonchunhyang Institute of Medi-Bio Science, Soon Chun Hyang University, Cheonan, South Korea.
  • 12 Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN, United States.
Abstract

Metabolic reprogramming during macrophage polarization supports the effector functions of these cells in health and disease. Here, we demonstrate that pyruvate dehydrogenase kinase (PDK), which inhibits the pyruvate dehydrogenase-mediated conversion of cytosolic pyruvate to mitochondrial acetyl-CoA, functions as a metabolic checkpoint in M1 macrophages. Polarization was not prevented by PDK2 or PDK4 deletion but was fully prevented by the combined deletion of PDK2 and PDK4; this lack of polarization was correlated with improved mitochondrial respiration and rewiring of metabolic breaks that are characterized by increased glycolytic intermediates and reduced metabolites in the TCA cycle. Genetic deletion or pharmacological inhibition of PDK2/4 prevents polarization of macrophages to the M1 phenotype in response to inflammatory stimuli (lipopolysaccharide plus IFN-γ). Transplantation of PDK2/4-deficient bone marrow into irradiated wild-type mice to produce mice with PDK2/4-deficient myeloid cells prevented M1 polarization, reduced obesity-associated Insulin resistance, and ameliorated adipose tissue inflammation. A novel, pharmacological PDK inhibitor, KPLH1130, improved high-fat diet-induced Insulin resistance; this was correlated with a reduction in the levels of pro-inflammatory markers and improved mitochondrial function. These studies identify PDK2/4 as a metabolic checkpoint for M1 phenotype polarization of macrophages, which could potentially be exploited as a novel therapeutic target for obesity-associated metabolic disorders and other inflammatory conditions.

Keywords

dichloroacetate; high-fat diet; inflammation; insulin resistance; macrophage polarization; metabolic reprogramming; pyruvate dehydrogenase kinase.

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