Year: 2014
Type: dissertation
Abstract: Emerging mosquito-borne viruses (arboviruses) constitute a large public health risk because of the ubiquity of mosquitoes and the potential for mosquito-human transmission. Neurotropic alphaviruses are of particular interest as they infect the central nervous system (CNS) of vertebrates, causing debilitating brain inflammation, damage, and (among some equine encephalitis viruses) fatality rates up to 40–70%. Many are listed as Category B agents of biodefense concern. There exist no effective human vaccines against neurotropic alphaviruses, underlining the need for effective antivirals, but no antiviral drugs are available for treating infection once the viruses have invaded the CNS. Therefore, the focus of our research was the development of new, novel compounds for the pharmacological intervention of CNS infection by neurotropic alphaviruses. To this end, we developed and synthesized novel analogues of a high-throughput screening lead to optimize potency in a western equine encephalitis virus (WEEV) replicon assay and improve physicochemical properties predictive of in vivo blood-brain barrier (BBB) permeability. We also synthesized rigidified analogues in order to identify bioactive conformations and requisite pharmacophore features. Furthermore, we established our own in-lab mouse liver microsome (MLM) assay and LC/MS/MS protocol to rapidly evaluate analogue metabolic stability. Together, this work has culminated in the identification of structural modifications that improve metabolic stability in the MLM assay, BBB-permeability in a BBB-PAMPA assay, aqueous solubility in a kinetic solubility assay. We also discovered properties that reduce efflux-transporter recognition in both a rhodamine123 and 3H-vinblastine uptake assay. We demonstrated that several reduced molecular weight (MW) pyrrole- and aniline-based compounds were capable of reducing titer against multiple virus families in live-virus assays by up to two orders of magnitude, and that at least one efflux-transporter-evasive pyrrole-based compound achieved measurable brain permeation in a pharmacokinetic mouse model. Moreover, our MLM metabolic stability protocol resulted in the discovery and promotion of compounds that demonstrated significant in vivo efficacy in an infected mouse model. These results represent a considerable step towards the development of a successful CNS-permeable antiviral for neurotropic alphaviruses.
Author: Scott J. Barraza
Language: English
Field: Medicine
Domain: Health Sciences
Open Access status: green
OpenAlex ID: W2755500214