Combating HIV-1 by Targeting Drug Efflux Transporters on the Macrophage Reservoir
Introduction. HIV-1 eradication has not been achieved so far due to the existence of the cellular reservoir in which the virus can reside and replicate even under antiretroviral drug therapy (ART). Infected macrophages, which represent a long-term viral reservoir have been shown to lead to viral rebound independently. In response to the environmental stimuli, macrophages can be polarized into different phenotypes: the pro-inflammatory M1 and the anti-inflammatory M2. Tobacco smoking and alcohol drinking, which are prevalent among people who are living with HIV-1, have been shown to promote HIV-1 progression and decrease the efficacy of antiretroviral drugs. A commonly used macrolide antibiotic azithromycin (AZM) has been shown to shift macrophage polarization in a murine macrophage cell line. In the previous research, we found that drug efflux transporters expressed differently between macrophage phenotypes. In this dissertation, we examined the effects of CSC, ethanol exposure, and AZM on the expression and function of clinically relevant drug efflux transporters, viral suppression of antiretroviral drugs, and macrophage polarization. Methods. The human monocytic cell lines U937 and the U1 cell line, which is derived from HIV-1 infected U937, were used and polarized to the M1 and M2 macrophages. Cells with the treatment of CSC, ethanol, and AZM were harvested for downstream analysis including macrophage polarization, oxidative stress, cytokine production, transporter expression and function, and viral suppression. Cells treated with IKK-16, an inhibitor of the NF-κB signaling pathway, were harvested for the analysis of transporter expression and function. Protease inhibitor lopinavir (LPV) was used to suppress viral replication and the intracellular LPV was measured using LC-MS/MS. Results. Cigarette smoke condensate (CSC) and AZM shifted M1 macrophage polarization to M2 while having minimal effects on the M2 macrophage polarization. Inhibiting macrophage subset-specific transporters significantly increased intracellular antiretroviral drug (ARV) concentrations and drug efficacy. Neither CSC nor ethanol had any effect on the transporter inhibition-mediated viral reduction. AZM modulated the expression of major drug efflux transporters in both macrophage subsets and increased intracellular ARV concentration in M2 macrophages. NF-κB and JNK are involved in the M1 macrophage polarization shift and NF-κB was also shown to regulate major transporter expression. Conclusion. Modulating the expression and function of macrophage subset-specific transporter expression can increase intracellular ARV concentration and drug efficacy of viral suppression. Targeting subset-specific transporter may be an effective way to increase intracellular ARV concentration in the macrophage reservoir.
azithromycin, drug efflux transporter, ethanol exposure, HIV reservoir, macrophage, tobacco smoking, Diseases, Medicine and Health Sciences, Pharmaceutics and Drug Design, Pharmacy and Pharmaceutical Sciences, Virus Diseases
University of Tennessee Health Science Center
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