CCR5 and the Blood Brain Barrier During HIV-1 Infection and Cell-Cell Communications

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

Preliminary Studies on Immune Response and Viral Pathogenesis of Zika Virus in Rhesus Macaques

Zika Virus (ZIKV) is primarily transmitted through mosquito bites. It can also be transmitted during sexual intercourse and in utero from mother to fetus. To gain preliminary insight into ZIKV pathology and immune responses on route of transmission, rhesus macaques (RMs) were inoculated with ZIKV (PRVABC59) via intravaginal (IVAG) (n = 3) or subcutaneous (sub Q) (n = 2) routes. Systemic ZIKV infection was observed in all RMs, regardless of the route of inoculation. After 9 days postinfection (dpi), ZIKV was not detected in the plasma of IVAG- and sub-Q-inoculated RMs. Importantly, RMs harbored ZIKV up to 60 dpi in various anatomical locations. Of note, ZIKV was also present in several regions of the brain, including the caudate nucleus, parietal lobe, cortex, and amygdala. These observations appear to indicate that ZIKV infection may be systemic and persistent regardless of route of inoculation. In addition, we observed changes in key immune cell populations in response to ZIKV infection. Importantly, IVAG ZIKV infection of RMs is associated with increased depletion of CD11C hi myeloid cells, reduced PD-1 expression in NK cells, and elevated frequencies of Ki67⁺ CD8⁺ central memory cells as compared to sub Q ZIKV-infected RMs. These results need to interpreted with caution due to the small number of animals utilized in this study. Future studies involving large groups of animals that have been inoculated through both routes of transmission are needed to confirm our findings

Data in support of NFκB and JNK pathways involvement in TLR3-mediated HIV-1 transactivation, expression of IL-6 and transcription factors associated with HIV-1 replication

In the present article, using human monocyte-derived macrophages and cell lines containing integrated copies of the HIV-1 promoter, we show the effects of TLR3 ligands on the pro-inflammatory cytokine IL-6. We further show the effects of TLR3 ligands on HIV-1 transactivation and transcription factors involved in HIV-1 replication. This article complements the data reported by the authors, “Toll-Like receptor-3 mediates HIV-1 transactivation via NFκB and JNK pathways, and histone acetylation, but prolonged activation suppresses Tat and HIV-1 replication” (Bhargavan et al., 2015) [1], and the interpretation of these data can be found in the research article published by the authors in Cellular Signaling in 2015 (Bhargavan et al., 2015) [1]. Keywords: TLR3, HIV transactivation, transcription factors, IL-6, human macrophage

SIV/SHIV-Zika co-infection does not alter disease pathogenesis in adult non-pregnant rhesus macaque model.

Due to the large geographical overlap of populations exposed to Zika virus (ZIKV) and human immunodeficiency virus (HIV), understanding the disease pathogenesis of co-infection is urgently needed. This warrants the development of an animal model for HIV-ZIKV co-infection. In this study, we used adult non-pregnant macaques that were chronically infected with simian immunodeficiency virus/chimeric simian human immunodeficiency virus (SIV/SHIV) and then inoculated with ZIKV. Plasma viral loads of both SIV/SHIV and ZIKV co-infected animals revealed no significant changes as compared to animals that were infected with ZIKV alone or as compared to SIV/SHIV infected animals prior to ZIKV inoculation. ZIKV tissue clearance of co-infected animals was similar to animals that were infected with ZIKV alone. Furthermore, in co-infected macaques, there was no statistically significant difference in plasma cytokines/chemokines levels as compared to prior to ZIKV inoculation. Collectively, these findings suggest that co-infection may not alter disease pathogenesis, thus warranting larger HIV-ZIKV epidemiological studies in order to validate these findings

Preliminary Studies on Immune Response and Viral Pathogenesis of Zika Virus in Rhesus Macaques

Zika Virus (ZIKV) is primarily transmitted through mosquito bites. It can also be transmitted during sexual intercourse and in utero from mother to fetus. To gain preliminary insight into ZIKV pathology and immune responses on route of transmission, rhesus macaques (RMs) were inoculated with ZIKV (PRVABC59) via intravaginal (IVAG) (n = 3) or subcutaneous (sub Q) (n = 2) routes. Systemic ZIKV infection was observed in all RMs, regardless of the route of inoculation. After 9 days postinfection (dpi), ZIKV was not detected in the plasma of IVAG- and sub-Q-inoculated RMs. Importantly, RMs harbored ZIKV up to 60 dpi in various anatomical locations. Of note, ZIKV was also present in several regions of the brain, including the caudate nucleus, parietal lobe, cortex, and amygdala. These observations appear to indicate that ZIKV infection may be systemic and persistent regardless of route of inoculation. In addition, we observed changes in key immune cell populations in response to ZIKV infection. Importantly, IVAG ZIKV infection of RMs is associated with increased depletion of CD11C hi myeloid cells, reduced PD-1 expression in NK cells, and elevated frequencies of Ki67+ CD8+ central memory cells as compared to sub Q ZIKV-infected RMs. These results need to interpreted with caution due to the small number of animals utilized in this study. Future studies involving large groups of animals that have been inoculated through both routes of transmission are needed to confirm our findings