The kynurenine pathway represents a major route for the catabolism of tryptophan (TRP). In the body, TRP is transported around the periphery either bound to albumin (90%) or in free form (10%), the two states existing in equilibrium (McMenamy 1965). However, only free form TRP can be transported across the blood-brain barrier (BBB) by the competitive and nonspecific L-type amino acid transporte...

Upregulation of kynurenine (KYN) formation from tryptophan (TRY) was associated with aging in animal and human studies. TRY - KYN metabolism is affected by the activities of TRY 2,3-dioxygenase 2 (TDO) and ATP-binding cassette (ABC) transporter regulating TRY access to intracellular TDO. We studied the effects of TDO inhibitor, alpha-methyl tryptophan (aMT), and ABC transported inhibitor, 5-met...

PURPOSE We employed a metabolomics-based approach with the goal to better understand the molecular signatures of glioblastoma cells and tissues, with an aim toward identifying potential targetable biomarkers for developing more effective and novel therapies. EXPERIMENTAL DESIGN We used liquid chromatography coupled with mass spectrometry (LC-MS/Q-TOF and LC-MS/QQQ) for the discovery and valid...

The mechanism of action of antipsychotic drugs is mainly associated with changes in dopaminergic system. The application of antipsychotic agents simultaneously produces changes in concentrations of metabolites (e.g. kynurenic acid - KYNA, 3-hydroxykynurenine - 3-OHKYN, kynurenine - KYN) of the kynurenine pathway, the pathway engaged in glutamatergic transmission. The increase in KYNA levels in ...

Tryptophan (Trp) catabolism mediated by indoleamine 2,3-dioxygenase (IDO) plays a central role in the regulation of T-cell-mediated immune responses. In this study, we also demonstrate that natural killer (NK)-cell function can be influenced by IDO. Indeed, l-kynurenine, a Trp-derived catabolite resulting from IDO activity, was found to prevent the cytokine-mediated up-regulation of the express...

Proteins can coordinate metal ions with endogenous nitrogen and oxygen ligands through backbone amino and carbonyl groups, but the amino acid side chains coordinating metals do not include tryptophan. Here we show for the first time the involvement of the tryptophan metabolite kynurenine in a protein metal-binding site. The crystal structure to 1.35 angstroms of MopE* from the methane-oxidizing...

The brain concentration of kynurenic acid (KYNA), a metabolite of the kynurenine pathway of tryptophan degradation and antagonist at both the glycine coagonist site of the N-methyl-D-aspartic acid receptor (NMDAR) and the a7 nicotinic acetylcholine receptor (a7nAChR), is elevated in the prefrontal cortex (PFC) of individuals with schizophrenia. This increase may be clinically relevant because h...