Kynurenic Acid Acts as a Signaling Molecule Regulating Energy Expenditure and Is Closely Associated With Metabolic Diseases

Abstract

Kynurenic acid (KYNA) is an important bio-active product of tryptophan metabolism. In addition to its well-known neuroprotective effects on mental health disorders, it has been proposed as a bio-marker for such metabolic diseases as atherosclerosis and diabetes. Emerging evidence suggests that KYNA acts as a signaling molecule controlling the networks involved in the balance of energy store and expenditure through GPR35 and AMPK signaling pathway. KYNA plays an important role in the pathogenesis and development of several endocrine and metabolic diseases. Exercise training promotes KYNA production in skeletal muscles and increases thermogenesis in the long term and limits weight gain, insulin resistance and inflammation. Additionally, KYNA is also present in breast milk and may act as an anti-obesity agent in infants. Although we are far from fully understanding the role of KYNA in our body, administration of KYNA, enzyme inhibitors or metabolites may serve as a potential therapeutic strategy for treating metabolic diseases. The present review provides a perspective on the current knowledge regarding the biological effects of KYNA in metabolic diseases and perinatal nutrition.

Older adults with cytomegalovirus reveal increased CD8+/CD4+EMRA T cells and elevated systemic levels of kynurenic acid

“…While the PLR and the SII were surprisingly lower, the LMR was elevated in CMV + persons compared to CMV À persons. A previous observational single-centred study showed that augmented levels of NLR and PLR are strong predictors of CMV infection in an Asian infant population [8]. Our exploratory findings on cellular immune inflammation markers in CMV + persons open new questions on a general immune cell phenotype-specific redistribution induced by CMV in older adults, and potential changes in these markers throughout lifespan.…”

Untargeted metabolomic profiling of sepsis-induced cardiac dysfunction

“…Compared with kynurenine, kynurenic acid is not metabolized and stable in solution ( 18 ). Hence, kynurenic acid is reported to be a potential candidate laboratory biomarker of metabolic diseases as atherosclerosis and diabetes ( 19 ). Tryptophan is an essential amino acid that can only be provided from nutrition intake.…”

Identification and characterization of the kynurenine pathway in the pond snail Lymnaea stagnalis

“…Furthermore, we found that Lym HAAO-like, Lym AADAT-like, and Lym KYAT-like are also mainly expressed in the gut. In rodents, KYAT-I and KYAT-III share similar expression patterns: their mRNA levels are much higher in the liver and neuroendocrine tissues than in the CNS 40 , 50 . This trend is reported also in LS for Lym KYAT-like.…”