Polarized macrophage subsets differentially express the drug efflux transporters MRP1 and BCRP, resulting in altered HIV production

Abstract

IntroductionMacrophages play an important role in HIV, where they are a cellular reservoir. Macrophages are polarized into two phenotypes: pro-inflammatory M1 macrophages and anti-inflammatory M2 macrophages, which may have altered expression of drug efflux transporters, including BCRP and MRP1. These differences may result in subtherapeutic concentrations of antiretrovirals inside of macrophages and viral replication.MethodsU937 and U1 cells were polarized to the M1 or M2 phenotype via IFN-γ and LPS, or IL-4, IL-13, and LPS. Transporter expression was assessed via PCR and Western blotting, and transporter function was assessed via fluorescent dye assays. Transporter function was blocked with the inhibitors MK571 or KO143. Protein expression was confirmed in monocyte-derived macrophages. p24 production was assessed in U1 cells via enzyme-linked immunosorbent assay.ResultsmRNA and protein analysis demonstrated higher expression of MRP1 in M1 macrophages, while BCRP expression was downregulated in M1 macrophages. Treatment with inhibitors of transporter function decreased the difference in intracellular fluorescence between polarized macrophages. Differences in protein expression, which were observed with U937 cells, were confirmed in monocyte-derived macrophages. M1, but not M2 cells treated with MK571, showed decreased p24 production, consistent with reported MRP1 transporter expression.ConclusionsThese results support our hypothesis that there is differential expression of MRP1 and BCRP on M1 and M2 polarized macrophages and suggests that these differences may result in altered intracellular concentrations of antiretrovirals in macrophages and alter viral production in these cells. Targeting these differences may be a strategy to decrease viral replication in HIV-infected individuals.

The HIV Reservoir in Monocytes and Macrophages

“…Changes in macrophage polarization and functions may therefore act as a mechanism for controlling latency and may contribute to stochastic reactivation and viremic “blips” often seen in patients receiving cART, but this remains to be investigated in vivo . Moreover, macrophage polarization can induce differential expression of drug efflux transporters, perhaps contributing to sub therapeutic antiretroviral concentrations (59). Recently, Ganor et al investigated the polarization states of ex vivo urethral macrophages from HIV-, and virologically suppressed HIV+ individuals and reported an intermediate polarization state (Mi) which expresses both M1 (IL-1R) and M2 (CD206) markers.…”

Mannose-decorated hybrid nanoparticles for enhanced macrophage targeting

“…U937 cells were purchased from American Type Culture Collection (ATCC Manassas, VA). Cells were polarized to the M1 or the M2 phenotype using protocols we have previously developed [29] , [30] . Cells were polarized to the M1 phenotype with 48 h of treatment of LPS (100 ng/mL, E. Coli origin, Sigma-Aldrich, St. Louis, Mo, USA) combined with INF-γ (20 ng/mL, Life Technologies, Carlsbad, CA, USA).…”

“…To study specific targeting of MDNPs on MR of macrophages, we choose the U937 cells as a model cell line which is commonly used in biomedical research, including pharmacology studies [27] , [28] . We have also extensively used this cell line, and shown that they are phenotypically similar to activated M1 and M2 monocyte derived macrophages [29] , [30] .…”

Tobacco and Antiretrovirals Modulate Transporter, Metabolic Enzyme, and Antioxidant Enzyme Expression and Function in Polarized Macrophages

“…In our previous research, we observed that drug efflux transporter levels varied between M1 and M2 phenotypes with a higher expression level of MRP1 but lower expression of PGP in M1 cells compared to M2 [48, 49]. Here, we aimed to clarify how a commonly utilized antiretroviral and cigarette smoke condensate interact in polarized macrophages, and how these influences change in the immunology of the M1 and M2 macrophages in terms of cytokine production and CYP enzyme dependent oxidative stress.…”

“…Macrophages are major targets of drugs including antibiotics and antiretrovirals [44-47]. Drug efflux transporters, which have historically been investigated as a cause for decreased absorption and low plasma concentrations of drugs, may also have effects on drug concentrations inside macrophages [48, 49]. Drug efflux transporters, including P-glycoprotein (PGP) and multidrug resistance protein 1(MRP1) are able to transport a diverse collection of drugs and toxins for the purpose of maintaining barrier function of sanctuary site tissues [50].…”