A novel bivalent HIV-1 entry inhibitor reveals fundamental differences in CCR5-μ-opioid receptor interactions between human astroglia and microglia

Abstract

Objective We explored whether the opiate, morphine, affects the actions of maraviroc, as well as a recently synthesized bivalent derivative of maraviroc linked to an opioid antagonist, naltrexone, on HIV-1 entry in primary human glia. Methods HIV-1 entry was monitored in glia transiently transfected with an LTR construct containing a luciferase reporter gene under control of a promoter for the HIV-1 transactivator protein Tat. The effect of maraviroc and the bivalent ligand ± morphine on CCR5 surface expression and cytokine release was also explored. Results Maraviroc inhibits HIV-1 entry into glial cells, while morphine negates the effects of maraviroc leading to a significant increase in viral entry. We also demonstrate that the maraviroc-containing bivalent ligand better inhibits R5-tropic viral entry in astrocytes than microglia compared to maraviroc when coadministered with morphine. Importantly, the inhibitory effects of the bivalent compound in astrocytes were not compromised by morphine. Exposure to maraviroc decreased the release of pro-inflammatory cytokines and restricted HIV-1-dependent increases in CCR5 expression in both astrocytes and microglia, while exposure to the bivalent had similar effect in astrocytes but not in microglia. CCR5-MOR stoichiometric ratio varied among the two cell types with CCR5 expressed at much higher levels than MOR in microglia, which could explain the effectiveness of the bivalent ligand in astrocytes compared to microglia. Conclusion A novel bivalent compound reveals fundamental differences in CCR5-MOR interactions and HIV-1 infectivity among glia, and has unique therapeutic potential in opiate abuse-HIV interactive comorbidity.

Bivalent Ligands Targeting Chemokine Receptor Dimerization: Molecular Design and Functional Studies

“…Upon infection with R5 HIVSF162 (with and without morphine), there was a significant increase in Tat (transactivator of transcription) expression in astrocytes that coincided with virus invasion (Fig. 8 ) [76]. When maraviroc was added, virus invasion was decreased, as expected.…”

“…On the other hand, addition of the bivalent compound 22 (“bivalent”) had a significant effect compared to maraviroc and maraviroc with morphine stimulation. Overall, there was a 3.3-fold decrease in virus entry compared to maraviroc alone and a 7-fold decrease when compared to maraviroc with morphine [76]. Importantly, morphine stimulation had no effect on the bivalent compound’s viral entry inhibition activity.…”

“…Importantly, morphine stimulation had no effect on the bivalent compound’s viral entry inhibition activity. Cytotoxicity assays indicated neither maraviroc nor 22 had any toxicity in the astrocytes [76]. The results showed that in a native system, the bivalent compound could act as a potent virus invasion inhibitor without deleterious effects caused by morphine stimulation.…”

Ibudilast (AV411), and its AV1013 analog, reduce HIV-1 replication and neuronal death induced by HIV-1 and morphine

“…Primary human microglial cells (ScienCell, Carlsbad, CA, USA) in culture, were transfected in vitro as described previously [39]. For detailed methods see Supplemental Digital Content 1.…”

“…ELISA was performed as described previously [39]. For detailed methods see Supplemental Digital Content 1.…”