Dolutegravir in Neurons and Macrophages: Molecular Mechanisms of Neurotoxicity and Neuroprotection
Date of Award
DScD (Doctor of Science in Dentistry)
Kelly L Jordan-Sciutto/ Cagla Akay-Espinoza
Despite effective antiretroviral (ARV) therapy (ART), human immunodeficiency virus (HIV)-associated neurocognitive disorders (HAND) persevere, affecting up to 30%-50% of all HIV-infected individuals. Although the end result involves neuronal damage and death in the absence of ART, neurons themselves are not directly infected by HIV; therefore, the pathological mechanisms are most likely indirect. Biomarkers of inflammation, immune activation, and oxidative stress remain elevated in the cerebrospinal fluid (CSF) of HIV-infected individuals throughout the course of infection regardless of the ART status. HAND is multifactorial, and both the presence of infected and activated macrophages, which are considered as a major source of HIV replication in the central nervous system (CNS), and ARV-mediated toxicity have been implicated in the persistence of HAND. Dolutegravir (DTG)-containing regimens are first-line treatment options recommended by many health guidelines. However, several studies have raised concerns regarding DTG-associated CNS abnormalities. Taken together, we hypothesize that DTG contributes to neuronal death directly via oxidative stress induction, while indirectly providing neuroprotection from HIV-induced neurotoxicity by inhibiting viral replication in macrophages. In this dissertation, we have identified two related yet independent mechanisms of DTG-mediated neurotoxicity, each of which may contribute to HAND pathogenesis. First, we show that DTG mediates neurotoxicity in vitro via increased reactive oxygen species (ROS) production and oxidative stress induction, as indicated by the alleviation of DTG-mediated neurotoxicity with the inducers of endogenous antioxidant response. Second, we generated supernatants from monocyte derived macrophages (MDM) exposed to DTG, with and without HIV infection or HIV/MDM and Mock/MDM, respectively. And we demonstrated that DTG-treated HIV/MDM has lower glutamate released compared to HIV-only/MDM. Moreover, DTG-treated HIV/MDM supernatants were not neurotoxic, compared to HIV/MDM supernatants. On the other hand, in the absence of HIV, DTG-treated Mock/MDM have increased expression of nuclear factor (erythroid-derived 2)-like 2 (NRF2), a transcription factor that regulate the expression of antioxidant and cytoprotective genes. To our knowledge, this is the first study looking at both neurons and macrophages simultaneously. Taken together, DTG may contribute to the pathology seen in HAND patients both directly and indirectly. From a translational point of view, these findings not only impact ARVs prescription based on possible adverse effects, but also highlights the importance of both targeted- drug therapy and adjunctive therapies.
Alboloushi, Naela, "Dolutegravir in Neurons and Macrophages: Molecular Mechanisms of Neurotoxicity and Neuroprotection" (2022). Dental Theses. 83.
Available for download on Friday, December 01, 2023