Background: Evidence from animal studies and post-mortem studies of brains from people with Huntington's disease (PwHD) has suggested that the kynurenine pathway (KP) may be dysregulated in Huntington's disease (HD).
Objective: To determine whether there are differences in KP metabolites in the CSF and plasma of PwHD versus healthy controls enrolled in the HDClarity study.
Methods: CSF and plasma samples from 141 PwHD with mild and moderate manifest disease and 75 healthy controls were analyzed for 3-hydroxykynurenine (3-OH-KYN), quinolinic acid, kynurenine, anthranilic acid, kynurenic acid, and tryptophan concentrations using validated high-performance liquid chromatography with tandem mass spectrometry (LC-MS/MS) methods.
Huntington's disease (HD) is caused by an expanded CAG trinucleotide repeat in exon 1 of the huntingtin () gene. We report the design of a series of pre-mRNA splicing modulators that lower huntingtin (HTT) protein, including the toxic mutant huntingtin (mHTT), by promoting insertion of a pseudoexon containing a premature termination codon at the exon 49-50 junction. The resulting transcript undergoes nonsense-mediated decay, leading to a reduction of mRNA transcripts and protein levels.
View Article and Find Full Text PDFDysregulation of the kynurenine metabolic pathway has been reported in several neurological conditions. Sensitive and selective LC-MS/MS methods have been validated for six kynurenine pathway metabolites in human cerebrospinal fluid and plasma. For each matrix, we validated three methods - one for the simultaneous determination of kynurenine, kynurenic acid, anthranilic acid and 3-hydroxy-kynurenine (four-analyte assay), one for quinolinic acid and one for tryptophan - using stable-isotopically labeled internal standards.
View Article and Find Full Text PDFTherapeutic interventions are being developed for Huntington's disease (HD), a hallmark of which is mutant huntingtin protein (mHTT) aggregates. Following the advancement to human testing of two [C]-PET ligands for aggregated mHTT, attributes for further optimization were identified. We replaced the pyridazinone ring of CHDI-180 with a pyrimidine ring and minimized off-target binding using brain homogenate derived from Alzheimer's disease patients.
View Article and Find Full Text PDFThe disposition of a novel kynurenine monooxygenase inhibitor, CHDI-340246, was investigated and in animals., there was minimal metabolic turnover of CHDI-340246 in all species. The protein binding was higher in human plasma (99.
View Article and Find Full Text PDFThe expanded polyglutamine-containing mutant huntingtin (mHTT) protein is implicated in neuronal degeneration of medium spiny neurons in Huntington's disease (HD) for which multiple therapeutic approaches are currently being evaluated to eliminate or reduce mHTT. Development of effective and orthogonal biomarkers will ensure accurate assessment of the safety and efficacy of pharmacologic interventions. We have identified and optimized a class of ligands that bind to oligomerized/aggregated mHTT, which is a hallmark in the HD postmortem brain.
View Article and Find Full Text PDFMutant huntingtin (mHTT) protein carrying the elongated N-terminal polyglutamine (polyQ) tract misfolds and forms protein aggregates characteristic of Huntington's disease (HD) pathology. A high-affinity ligand specific for mHTT aggregates could serve as a positron emission tomography (PET) imaging biomarker for HD therapeutic development and disease progression. To identify such compounds with binding affinity for polyQ aggregates, we embarked on systematic structural activity studies; lead optimization of aggregate-binding affinity, unbound fractions in brain, permeability, and low efflux culminated in the discovery of compound , which exhibited target engagement in autoradiography (ARG) studies in brain slices from HD mouse models and postmortem human HD samples.
View Article and Find Full Text PDFThe blood-brain barrier (BBB) is responsible for the homeostasis between the cerebral vasculature and the brain and it has a key role in regulating the influx and efflux of substances, in healthy and diseased states. Stem cell technology offers the opportunity to use human brain-specific cells to establish in vitro BBB models. Here, we describe the establishment of a human BBB model in a two-dimensional monolayer culture, derived from human induced pluripotent stem cells (hiPSCs).
View Article and Find Full Text PDFHuntington's disease (HD) is a neurodegenerative disease caused by polyglutamine expansion in the huntingtin protein. For drug candidates targeting HD, the ability to cross the blood-brain barrier (BBB) and reach the site of action in the central nervous system (CNS) is crucial for achieving pharmacological activity. To assess the permeability of selected compounds across the BBB, we utilized a two-dimensional model composed of primary porcine brain endothelial cells and rat astrocytes.
View Article and Find Full Text PDFNeuroactive metabolites in the kynurenine pathway of tryptophan catabolism are associated with neurodegenerative disorders. Tryptophan is transported across the blood-brain barrier and converted via the kynurenine pathway to N-formyl-L-kynurenine, which is further degraded to L-kynurenine. This metabolite can then generate a group of metabolites called kynurenines, most of which have neuroactive properties.
View Article and Find Full Text PDFAMPA receptors (AMPARs) are an important therapeutic target in the CNS. A series of substituted benzobistriazinone, benzobispyrimidinone and related derivatives have been prepared with high potency and selectivity for the allosteric binding site of AMPARs. Further improvements have been made to previously reported series of positive AMPAR modulators and these compounds exhibit excellent in vivo activity and improved in vivo metabolic stability with up to 100% oral bioavailability in rat.
View Article and Find Full Text PDFAMPA receptors (AMPARs) have been demonstrated to be an important therapeutic CNS target. A series of substituted benzotriazinone and benzopyrimidinone derivatives were prepared with the aim to improve in vivo activity over the previously reported bis-benzoxazinone based AMPAKINE series from our laboratory. These compounds were shown to be potent, positive allosteric AMPAR modulators that have better in vivo activity and improved metabolic stability over the analogous benzoxazinone derivatives.
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