The autonomic nervous system is one of the major neural pathways activated by stress. In situations that are often associated with chronic stress, such as major depressive disorder, the sympathetic nervous system can be continuously activated without the normal counteraction of the parasympathetic nervous system. As a result, the immune system can be activated with increased levels of pro-infla...

Pseudomonas aeruginosa is an opportunistic pathogen that causes serious infections in immunocompromised patients and those with cystic fibrosis (CF). This gram-negative bacterium uses multiple cell-to-cell signals to control numerous cellular functions and virulence. One of these signals is 2-heptyl-3-hydroxy-4-quinolone, which is referred to as the Pseudomonas quinolone signal (PQS). This sign...

Communication between cancer cells and their microenvironment plays an important role in cancer development, but the precise mechanisms by which cancer-associated fibroblasts (CAF) impact anti-cancer immunity and cancer progression in lung cancer are poorly understood. Here, we report that lung fibroblasts when activated by lung cancer cells produce tryptophan metabolite kynurenine (Kyn) that i...

The present study describes the isolation of a protein from Escherichia coli possessing kynurenine aminotransferase (KAT) activity and its identification as aspartate aminotransferase (AspAT). KAT catalyses the transamination of kynurenine and 3-hydroxykynurenine to kynurenic acid and xanthurenic acid respectively, and the enzyme activity can be easily detected in E. coli cells. Separation of t...

The role of the amino acid tryptophan in the generation of 5-hydroxy-tryptamine (5-HT) has been expanded over the past 30 years with recognition that its oxidation by indoleamine-2,3-dioxygenase (IDO) results in the formation of kynurenine and metabolites which regulate neuronal excitability, psychiatric status, immune cell activity and balance, and probably implantation and the development of ...

BACKGROUND Physical exercise has well-characterized positive effects on depressive symptoms. The underlying biologic mechanisms are, however, far from established. A recently discovered mechanism has linked the enhanced conversion of kynurenine to kynurenic acid (KYNA) to an increased resilience toward stress-induced depression in mice. The aim of this study was to translate these findings to h...

Depressive disorders often run in families, which, in addition to the genetic component, may point to the microbiome as a causative agent. Here, we employed a combination of behavioral, molecular and computational techniques to test the role of the microbiota in mediating despair behavior. In chronically stressed mice displaying despair behavior, we found that the microbiota composition and the...

Disrupted kynurenine pathway (KP) metabolism has been implicated in the progression of neurodegenerative disease, psychiatric disorders and cancer. Modulation of enzyme activity along this pathway may therefore offer potential new therapeutic strategies for these conditions. Considering their prominent positions in the KP, the enzymes indoleamine 2,3-dioxygenase, kynurenine 3-monooxygenase and ...

Methods and Results-—Rat plasma samples from RIPC and control groups were analyzed using a targeted metabolomic approach aimed at measuring 188 metabolites. Principal component analysis and orthogonal partial least-squares discriminant analysis were used to identify the metabolites that discriminated between groups. Plasma samples from 50 patients subjected to RIPC were secondarily explored to ...

Tryptophan contents of liver, serum and kidney were determined in normal and vitamin-B-6-deficient rats after tryptophan injection. Tryptophan contents of normal and B-6-deficient liver were different, but not those in serum and kidney. Both kynurenine and 3-hydroxykynurenine accumulated in B-6-deficient liver more than in the normal. The 3-hydroxykynurenine contents after tryptophan injection ...