Graduation Date

Summer 8-14-2015

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Programs

Pharmacology and Experimental Neuroscience

First Advisor

Georgette D. Kanmogne

Abstract

Human Immunodeficiency Virus (HIV-1) infection often results in blood-brain barrier (BBB) dysfunction and central nervous system (CNS) impairment. Since most viral strains that cross the BBB and enter the CNS are macrophage-tropic and use the C-C chemokine receptor type-5 (CCR5) to enter and infect target cells, we hypothesized that CCR5 plays a major role in monocytes-endothelial interactions and HIV-induced BBB dysfunction. Because the cytoskeleton is responsible for cellular morphology and motility, we further hypothesized that HIV-induced monocyte-endothelial interactions and transendothelial migration involve cytoskeletal changes and that CCR5 blockers would also affect these changes. To this end we used two small molecule CCR5 antagonists, TAK-779 and maraviroc (MVR), to evaluate the role of CCR5 on cytoskeletal changes in HIV-1-infected monocytes following monocyte-endothelial interactions. We found that HIV-1 infection of monocytes resulted in the upregulation of cytoskeletal-associated proteins following monocyte-endothelial interactions. Proteins identified included Rac1, ERK1/2, and cortactin. Rac1 phosphorylation at serine 71 (s71) was upregulated in our in vitro studies and this upregulation was validated in analyses of ex-vivo brain tissues of HIV-1-infected humans. We next examined the effect of MVR treatment on HIV-1-induced BBB injury and CNS infection in vivo using humanized mice. We hypothesized that MVR treatment could diminish HIV-induced BBB injury and CNS infection. HIV-1 infection resulted in decreased expression of the tight junction proteins claudin-5 and ZO-2 in the animals’ brain blood vessels and MVR treatment partially attenuated these changes. Furthermore, our data showed that MVR enters the CNS and MVR treatment reduced viral loads in brain tissues. In conclusion, this study suggests that blocking CCR5 can diminish HIV-1-induced cytoskeletal changes, diminish BBB injury and CNS infection.

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