Kynurenic Acid and Gpr35 Regulate Adipose Tissue Energy Homeostasis and Inflammation

Publication date: 6 February 2018
Source:Cell Metabolism, Volume 27, Issue 2
Author(s): Leandro Z. Agudelo, Duarte M.S. Ferreira, Igor Cervenka, Galyna Bryzgalova, Shamim Dadvar, Paulo R. Jannig, Amanda T. Pettersson-Klein, Tadepally Lakshmikanth, Elahu G. Sustarsic, Margareta Porsmyr-Palmertz, Jorge C. Correia, Manizheh Izadi, Vicente Martínez-Redondo, Per M. Ueland, Øivind Midttun, Zachary Gerhart-Hines, Petter Brodin, Teresa Pereira, Per-Olof Berggren, Jorge L. Ruas
The role of tryptophan-kynurenine metabolism in psychiatric disease is well established, but remains less explored in peripheral tissues. Exercise training activates kynurenine biotransformation in skeletal muscle, which protects from neuroinflammation and leads to peripheral kynurenic acid accumulation. Here we show that kynurenic acid increases energy utilization by activating G protein-coupled receptor Gpr35, which stimulates lipid metabolism, thermogenic, and anti-inflammatory gene expression in adipose tissue. This suppresses weight gain in animals fed a high-fat diet and improves glucose tolerance. Kynurenic acid and Gpr35 enhance Pgc-1α1 expression and cellular respiration, and increase the levels of Rgs14 in adipocytes, which leads to enhanced beta-adrenergic receptor signaling. Conversely, genetic deletion of Gpr35 causes progressive weight gain and glucose intolerance, and sensitizes to the effects of high-fat diets. Finally, exercise-induced adipose tissue browning is compromised in Gpr35 knockout animals. This work uncovers kynurenine metabolism as a pathway with therapeutic potential to control energy homeostasis.

Graphical abstract

Teaser

Kynurenine is a neurotoxic metabolite detoxified to kynurenic acid by exercised skeletal muscle. Now, Agudelo et al. show that the rise in circulating kynurenic acid activates Gpr35 in adipose tissue and increases energy expenditure. This improves the metabolic consequences of high-fat diet feeding in mice. Gpr35 deletion causes progressive weight gain.


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