Biology subjects
Publications and source records attributed to Cash, M. N..
Withdrawal StatementThe authors have withdrawn this manuscript due to a duplicate posting of manuscript number BIORXIV/2022/490630. Therefore, the authors do not wish this work to be cited as reference for the project. If you have any questions, please contact the corresponding author. The correct preprint can be found at doi: 10.1101/2022.05.04.490630.
During the course of infection, human immunodeficiency virus (HIV) maintains a stably integrated reservoir of replication-competent viruses within the host genome that are unaffected by antiretroviral therapy. Curative advancements rely heavily on targeting the anatomical reservoirs, though determinants of their evolutionary origins through phyloanatomic inference remain ill-supported through current sequencing and sequence analysis strategies. The vast replication-defective genomic landscape that comprises the HIV DNA population is often discarded in these evolutionary endeavors, despite key information regarding competent ancestry that can be gained from captured genomic regions outside the historically used viral envelope gene. Here, we describe the application of small-amplicon, single-cell DNA sequencing to blood and lymph node samples from a treatment-interrupted S[imian]IV-infected animal model and evaluate the contribution of genome coverage and inclusion on phylogenetic resolution and phyloanatomic inference. Findings from this study point to incomplete genomes as a significant source of phylogenetic information on movement of virus between tissue reservoirs during therapy.
Mayaro virus (MAYV) is an emergent arthropod-borne virus that causes an acute febrile illness accompanied by arthralgia, similar to chikungunya virus. Increasing urbanization of MAYV outbreaks in the Americas has led to concerns that this virus could further expand its geographic range. Given the potential importance of this pathogen, we sought to fill some critical gaps in knowledge regarding MAYV infectivity and geographic variation. This study describes the cytopathogenicity of MAYV in human dermal fibroblasts, human skeletal muscle satellite cells, human embryonic kidney cells (HEK), peripherally derived human macrophages, and Vero cells. MAYV strain isolated from Bolivia (MAYV-U) infected cells more rapidly compared to MAYV strains isolated in Peru and Brazil (MAYV-P; MAYV-B), with high titers (1x108 pfu/ml) peaking at 37 hours post infection. MAYV-U also caused the most cytopathic effect in a time dependent manner. Furthermore, differently from the other two prototypic strains, MAYV-U harbors unique mutations in the E2 protein, D60G and S205F, likely to interact with the host cell receptor, which may explain the observed differences in infectivity. We further demonstrate that pre-treatment of cells with interferon-{beta} inhibited viral replication in a dose-dependent manner. Together, these findings advance our understanding of MAYV infection of human target cells and provide initial data regarding MAYV phenotypic variation according to geography. Author SummaryArthropod-borne viruses are of great public health concern, causing epidemics worldwide due to climate change, changes in land use, rapid urbanization, and the expanding geographic ranges of suitable vectors. Among these viruses, Mayaro is an emerging virus for which little is currently known. This study aims to answer fundamental questions of Mayaro virus biology using three geographically distinct viral strains to examine variability in infection kinetics and infectivity in susceptible cell types. We found one geographic isolate to have accelerated infection kinetics and increased cell damage because of infection. To better understand what was unique about this isolate, we compared their envelope protein, which is critical for entry into a cell. We found that the isolate with increased replication kinetics possessed mutations at sites that may promote viral entry, which could explain these findings. Together, these findings further our understanding of Mayaro virus biology and provide insight into factors that contribute to Mayaro transmission and infectivity.
BackgroundDespite improvements in antiretroviral therapy, human immunodeficiency virus type 1 (HIV-1)-associated neurocognitive disorders (HAND) remain prevalent in subjects undergoing therapy. HAND significantly affects individuals quality of life, as well as adherence to therapy, and, despite the increasing understanding of neuropathogenesis, no definitive diagnostic or prognostic marker has been identified. ResultsWe investigated transcriptomic profiles in frontal cortex tissues of Simian immunodeficiency virus (SIV)-infected Rhesus macaques sacrificed at different stages of infection. Gene expression was compared among SIV-infected animals (n=11), with or without CD8+ lymphocyte depletion, based on detectable (n=6) or non-detectable (n=5) presence of the virus in frontal cortex tissues. Significant enrichment in activation of monocyte and macrophage cellular pathways was found in animals with detectable brain infection, independently from CD8+ lymphocyte depletion. In addition, transcripts of four poly (ADP-ribose) polymerases (PARPs) were up-regulated in the frontal cortex, which was confirmed by real-time polymerase chain reaction. ConclusionsOur results shed light on involvement of PARPs in SIV infection of the brain and their role in SIV-associated neurodegenerative processes. Inhibition of PARPs may provide an effective novel therapeutic target for HIV-related neuropathology.
Infection of HIV-1 remains incurable because long-lived, latently-infected cells persist during prolonged antiretroviral therapy. Attempts to pharmacologically reactivate and purge the latent reservoir with latency reactivating agents (LRAs) such as protein kinase C (PKC) agonists (e.g. ingenol A) or histone deacetylase (HDAC) inhibitors (e.g. SAHA) have shown promising but incomplete efficacy. Using the J-Lat T cell model of HIV latency, we found that the plant-derived compound harmine enhanced the efficacy of existing PKC agonist LRAs in reactivating latently-infected cells. Treatment with harmine increased not only the number of reactivated cells but also increased HIV transcription and protein expression on a per-cell basis. Importantly, we observed an additive effect when harmine was used in combination with ingenol A and the HDAC inhibitor SAHA. An investigation into the mechanism revealed that harmine, when used with LRAs, increased the availability of transcription factors needed for viral reactivation such as NF{kappa}B, MAPK p38, and ERK1/2. We also found that harmine treatment resulted in reduced expression of HEXIM1, a negative regulator of transcriptional elongation. Despite harmines reported inhibitory effects on DYRK1A and consequent enhancement of NFAT signaling, the HIV reactivating effects of harmine occurred independent of DYRK1A and NFAT. Harmine increases the efficacy of LRAs by increasing the availability of HIV-1 transcription factors and decreasing expression of HEXIM1. Combination therapies with harmine and LRAs could benefit patients by achieving deeper reactivation of the latent pool of HIV provirus.