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Collman, R.

Publications and source records attributed to Collman, R..

2 recordsLinked to original sources

Epigenetic Landscape of HIV Infection in Primary Human Macrophage

HIV-infected macrophages are long-lived cells that sustain persistent virus expression, which is both a barrier to viral eradication and contributor to neurological complications in patients despite antiretroviral therapy (ART). To better understand the regulation of HIV in macrophages, we compared HIV infected primary human monocyte derived macrophages (MDM) to acutely infected primary CD4 T cells and Jurkat cells latently infected with HIV (JLAT 8.4). HIV genomes in MDM were actively transcribed despite enrichment with heterochromatin-associated H3K9me3 across the complete HIV genome in combination with elevated activation marks of H3K9ac and H3K27ac at the LTR. Macrophage patterns contrasted with JLAT cells, which showed conventional bivalent H3K4me3/H3K27me3, and acutely infected CD4 T cells, which showed an intermediate epigenotype. 5 -methylcytosine (5mC) was enriched across the HIV genome in latently infected JLAT cells, while 5 -hydroxymethylcytosine (5hmc) was enriched in CD4 and MDM. HIV infection induced multinucleation of MDMs along with DNA damage associate p53 phosphorylation, as well as loss of TET2 and the nuclear redistribution of 5-hydoxymethylation. Taken together, our findings suggest that HIV induces a unique macrophage nuclear and transcriptional profile, and viral genomes are maintained in a non-canonical bivalent epigenetic state. ImportanceMacrophages serve as a reservoir for long-term persistence and chronic production of HIV. We found an atypical epigenetic control of HIV in macrophages marked by heterochromatic H3K9me3 despite active viral transcription. HIV infection induced changes in macrophage nuclear morphology and epigenetic regulatory factors. These findings may identify new mechanisms to control chronic HIV expression in infected macrophage.

microbiology↗

Marginal Effects of Systemic CCR5 Blockade with Maraviroc on Oral Simian Immunodeficiency Virus Transmission to Infant Macaques

Current approaches do not eliminate all HIV-1 maternal-to-infant transmissions (MTIT); new prevention paradigms might help avert new infections. We administered Maraviroc (MVC) to rhesus macaques (RMs) to block CCR5-mediated entry, followed by repeated oral exposure of a CCR5-dependent clone of simian immunodeficiency virus (SIV)mac251 (SIVmac766). MVC significantly blocked the CCR5 coreceptor in peripheral blood mononuclear cells and tissue cells. All control animals and 60% of MVC-treated infant RMs became infected by the 6th challenge, with no significant difference between the number of exposures (p=0.15). At the time of viral exposures, MVC plasma and tissue (including tonsil) concentrations were within the range seen in humans receiving MVC as a therapeutic. Both treated and control RMs were infected with only a single transmitted/founder variant, consistent with the dose of virus typical of HIV-1 infection. The uninfected RMs expressed the lowest levels of CCR5 on the CD4+ T cells. Ramp-up viremia was significantly delayed (p=0.05) in the MVC-treated RMs, yet peak and postpeak viral loads were similar in treated and control RMs. In conclusion, in spite of apparent effective CCR5 blockade in infant RMs, MVC had marginal impact on acquisition and only a minimal impact on post infection delay of viremia following oral SIV infection. Newly developed, more effective CCR5 blockers may have a more dramatic impact on oral SIV transmission than MVC.\n\nImportanceWe have previously suggested that the very low levels of simian immunodeficiency virus (SIV) maternal-to-infant transmissions (MTIT) in African nonhuman primates that are natural hosts of SIVs are due to a low availability of target cells (CCR5+ CD4+ T cells) in the oral mucosa of the infants, rather than maternal and milk factors. To confirm this new MTIT paradigm, we performed a proof of concept study, in which we therapeutically blocked CCR5 with maraviroc (MVC) and orally exposed MVC treated and naive infant rhesus macaques to SIV. MVC had only a marginal effect on oral SIV transmission. However, the observation that the infant RMs that remained uninfected at the completion of the study, after 6 repeated viral challenges, had the lowest CCR5 expression on the CD4+ T cells prior to the MVC treatment, appear to confirm our hypothesis, also suggesting that the partial effect of MVC is due to a limited efficacy of the drug. Newly, more effective CCR5 inhibitors may have a better effect in preventing SIV and HIV transmission.

immunology↗