Title:Kynurenine Aminotransferases and the Prospects of Inhibitors for the Treatment of Schizophrenia
Volume: 22
Issue: 24
Author(s): Gayan S. Jayawickrama, Richard R. Sadig, Guanchen Sun, Alireza Nematollahi, Naveed A. Nadvi, Jane R. Hanrahan, Mark D. Gorrell and W. Bret Church
Affiliation:
关键词:
BFF-122
摘要: Schizophrenia is a complex neuropsychiatric disorder with limited treatment options and
highly debilitating symptoms, leading to poor personal, social, and occupational outcomes for an afflicted
individual. Our current understanding of schizophrenia suggests that dopaminergic and glutamatergic
systems have a significant role in the pathogenesis of the disease. Kynurenic acid, an endogenous
glutamate antagonist, is found in elevated concentrations in the prefrontal cortex and cerebrospinal
fluid of patients with schizophrenia, and this affects neurotransmitter release in a similar manner to previously observed
psychotomimetic agents, such as phencyclidine, underlining the molecular basis to its link in schizophrenia pathophysiology.
Kynurenic acid is a breakdown product of tryptophan degradation, through a transamination process mediated
by kynurenine aminotransferase (KAT) enzymes. There are four KAT homologues reported, all of which are pyridoxal 5’-
phosphate-dependent enzymes. All four KAT isoforms have been analysed structurally and biochemically, however the
most extensive research is on KAT-I and KAT-II. These two enzymes have been targeted in structure-based drug design
as a means of normalising raised kynurenic acid levels. The most potent KAT-I inhibitors and KAT-II inhibitors include
phenylhydrazone hexanoic acid derivatives and a pyrazole series of compounds, respectively. KAT inhibitors have been
shown to be effective in reducing kynurenic acid production, with accompanying changes in neurotransmitter release and
pro-cognitive effects seen in animal studies. This review will discuss the characteristics pertaining to the different KAT
isoforms, and will highlight the development of significant KAT inhibitors. KAT inhibitors have great potential for therapeutic
application and represent a novel way in treating schizophrenia.