Biology subjects

Margolis, D.

Publications and source records attributed to Margolis, D..

4 recordsLinked to original sources

bioRxiv2025

Single cell analysis of HIV expression and integration sites reveals robust viral expression across diverse chromatin environments

Entry of HIV into latency is determined by a combination of factors, including fluctuations in the viral Tat protein, as well as the transcriptomic phenotype of the host cell. Determining the impact of the proviral integration site on viral expression has been challenging due to difficulty in measuring integration site and viral expression from the same cell. To investigate the influence of the HIV integration site on HIV expression, we analyzed a combined scRNAseq/scATACseq dataset from 117,610 HIV infected primary CD4 T cells. We used the scATACseq data to recover HIV integration site information from 1530 cells, and correlated this information with viral RNA reads in the scRNAseq data. We observed that, overall, HIV expression did not differ depending on the genomic features of viral integration, such as genic vs non genic, intron vs exon and forward versus reverse orientation. Furthermore, we found that there was no significant difference in HIV expression across 15 distinct chromatin compartments. Additionally, analysis of expression for host genes that were the target of proviral integration revealed strong upregulation of expression of the targeted host gene in [~]5% of the infected cells. This insertional activation occurred almost exclusively when HIV was integrated in the same orientation as the host cell gene and occurred as a result of integration within diverse positions across a gene. These findings suggest that HIV expression is relatively robust to the genomic context of the HIV integration site, and that HIV can strongly upregulate expression of integration site genes during infection.

microbiology↗

bioRxiv2025

Single cell multiomic analysis of the impact of Delta-9-tetrahydrocannabinol on HIV infected CD4 T cells

Cannabis use is prevalent among individuals living with HIV in the United States, but the impact of cannabis exposure on the reservoir of latently infected cells that persists during antiretroviral therapy (ART) remains unclear. To address this gap, we analyzed the effect of {Delta}-9-tetrahydrocannabinol (THC) on primary CD4 T cells that were latently infected with HIV. We found that THC had no detectable effect on baseline or latency reversing agent (LRA) stimulated HIV expression, or on expression of an activation marker (CD38). However, using an integrated multiomic single-cell analysis of genome-wide chromatin accessibility and gene expression, we observed altered expression of several hundred genes in HIV infected CD4 T cells after THC exposure, including transcriptional downregulation of genes involved in protein translation and antiviral pathways, indicating that THC suppresses innate immune activation in infected cells. Additionally, chromatin accessibility analysis demonstrated upregulated chromatin binding activity for the transcriptional regulator CTCF, and reduced activity for members of the ETS transcription factor family in infected cells after THC exposure. These findings provide insights into the mechanisms by which cannabis use could influence the persistence of HIV within cellular reservoirs and the molecular phenotype of latently infected cells. Further elucidation of the underlying mechanisms involved in THC-mediated changes to HIV infected cells, will lead to an improved understanding of the impact of cannabis use on the HIV reservoir. ImportanceCannabis use is common among individuals living with HIV, but the long-term effects of cannabis use on the HIV reservoir are not yet studied completely. We employed advanced single-cell technologies to reveal how cannabis components, specifically THC, influence HIV-infected immune cells and their pattern of gene expression. We found that, while THC doesnt reactivate virus in latently infected cells, it alters the molecular characteristics of these infected immune cells. These findings are important because they underscore how cannabis could regulate persistent infection in people living with HIV. Understanding these cellular changes in response to THC could be helpful for successful treatment for people living with HIV.

molecular biology↗

bioRxiv2019

Diversity and complexity of the large surface protein family in the compacted genomes of various Pneumocystis species

Pneumocystis, a major opportunistic pathogen in patients with a broad range of immunodeficiencies, contains abundant surface proteins encoded by a multi-copy gene family, termed the major surface glycoprotein (Msg) gene superfamily. This superfamily has been identified in all Pneumocystis species characterized to date, highlighting its important role in Pneumocystis biology. In this report, through a comprehensive and in-depth characterization of 459 msg genes from 7 Pneumocystis species, we demonstrate, for the first time, the phylogeny and evolution of conserved domains in Msg proteins, and provide detailed description of the classification, unique characteristics and phylogenetic relatedness of five Msg families. We further describe the relative expression levels of individual msg families in two rodent Pneumocystis species, the substantial variability of the msg repertoires in P. carinii from laboratory and wild rats, and the distinct features of the expression site for the classic msg genes in Pneumocystis from 8 mammalian host species. Our analysis suggests a wide variety of functions for this superfamily, not only conferring antigenic variation to allow immune evasion but also mediating life-stage development, optimizing cell mobility and adhesion, and adapting to specific host niches or environmental conditions. This study provides a rich source of information that lays the foundation for the continued experimental exploration of the functions of the Msg superfamily in Pneumocystis biology.

molecular biology↗

bioRxiv2019

Degradation of Polycomb Repressive Complex 2 with an EED-targeted Bivalent Chemical Degrader

Protein degradation via the use of bivalent chemical degraders provides an alternative strategy to block protein function and assess the biological roles of putative drug targets. This approach capitalizes on the advantages of small molecule inhibitors while moving beyond the restrictions of traditional pharmacology. Herein we report a first-in-class chemical degrader (UNC6852) that targets Polycomb Repressive Complex 2 (PRC2). UNC6852 contains an EED226 derived ligand and a ligand for VHL which bind to the WD40 aromatic cage of EED and CRL2VHL, respectively, to induce proteasomal degradation of PRC2 components, EED, EZH2, and SUZ12. Degradation of PRC2 with UNC6852 blocks the histone methyltransferase activity of EZH2, decreasing H3K27me3 levels in HeLa cells and diffuse large B-cell lymphoma (DLBCL) cells containing an EZH2Y641N gain-of-function mutation. UNC6852 degrades both wild type EZH2 and EZH2Y641N, and additionally displays anti-proliferative effects in this cancer model system.\n\n\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=171 SRC=\"FIGDIR/small/676965v1_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (34K):\norg.highwire.dtl.DTLVardef@5b8f01org.highwire.dtl.DTLVardef@1098ff7org.highwire.dtl.DTLVardef@caa1a9org.highwire.dtl.DTLVardef@13b6bfc_HPS_FORMAT_FIGEXP M_FIG C_FIG

cancer biology↗