The kynurenine pathway metabolizes tryptophan into nicotinamide adenine dinucleotide, producing a number of intermediary metabolites, including 3-hydroxy kynurenine and quinolinic acid, which are involved in the neurodegenerative mechanisms that underlie Alzheimer’s disease (AD). Indolamine 2,3-dioxygenase (IDO), the first and rate-limiting enzyme of this pathway, is increased in AD, and it has been hypothesized that blocking this enzyme may slow the progression of AD. In this study, we treated male and female 3xTg-AD and wild-type mice with the novel IDO inhibitor DWG-1036 (80 mg/kg) or vehicle (distilled water) from 2 to 6 months of age and then tested them in a battery of behavioral tests that measured spatial learning and memory (Barnes maze), working memory (trace fear conditioning), motor coordination and learning (rotarod), anxiety (elevated plus maze), and depression (tail suspension test). The 3xTg-AD mice treated with DWG-1036 showed better memory in the trace fear conditioning task and significant improvements in learning but poorer spatial memory in the Barnes maze. DWG-1036 treatment also ameliorated the behaviors associated with increased anxiety in the elevated plus maze and depression-like behaviors in the tail suspension test in 3xTg-AD mice. However, the effects of DWG-1036 treatment on the behavioral tasks were variable, and sex differences were apparent. In addition, high doses of DWG-1036 resulted in reduced body weight, particularly in females. Taken together, our results suggest that the kynurenine pathway is a promising target for treating AD, but more work is needed to determine the effective compounds, examine sex differences, and understand the side effects of the compounds.

Inhibition of indoleamine 2,3-dioxygenase (IDO1) is an attractive immunotherapeutic approach for the treatment of a variety of cancers. Dysregulation of this enzyme has also been implicated in other disorders including Alzheimer's disease and arthritis. Herein, we report the structure-based design of two related series of molecules: 1-substituted 5-indoleimidazoles and1-substituted 5-phenylimidazoles. The latter (and more potent) series was accessed through an unexpected rearrangement of an imine intermediate during a Van Leusen imidazole synthesis reaction. Evidence for the binding modes for both inhibitor series is supported by computational and structure-activity relationship studies.

Rapid mutation of the influenza virus through genetic mixing raises the prospect of new strains that are both highly transmissible and highly lethal, and which have the ability to evade both immunization strategies (through mutation of hemagglutinin) and current therapies (through mutation of neuraminidase). Inspired by a need for next-generation therapeutics, a synthetic strategy for a new class of rigid, bicyclic inhibitors of influenza neuraminidase is reported.

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SummaryDipolar addition of cyclic azomethine imines with cyclic vinyl sulfones gave rise to functionalized tricycles that exhibited fluxional behavior in solution at room temperature. The scope of the synthetic methodology was explored, and the origin of the fluxional behavior was probed by NMR methods together with DFT calculations. This behavior was ultimately attributed to stereochemical inversion at one of two nitrogen centers embedded in the tricyclic framework. Two tetracycles were also synthesized, and the degree of signal-broadening in the NMR spectra was found to depend on the presence of substitution next to the inverting nitrogen center.