Mitochondrial toxicity (Mito-Tox) risk has increased due to the administration of several classes... more Mitochondrial toxicity (Mito-Tox) risk has increased due to the administration of several classes of drugs, particularly some life-long antiretroviral drugs for HIV+ individuals. However, no suitable in vitro assays are available to test long-term Mito-Tox (≥4 weeks). The goal of this study is to develop a 3D spheroid system of human primary urine-derived stem cells (USC) for the prediction of drug-induced delayed Mito-Tox. The cytotoxicity and Mito-Tox were assessed in 3D USC spheroids 4 weeks after treatment with antiretroviral drugs: zalcitabine (ddC; 0.1, 1 and 10 µM), tenofovir (TFV; 3, 30 and 300 µM) or Raltegravir (RAL; 2, 20 and 200 µM). Rotenone (RTNN, 10 µM) and 0.1% DMSO served as positive and negative controls. Despite only mild cytotoxicity, ddC significantly inhibited the expression of oxidative phosphorylation enzyme Complexes I, III, and IV; and RAL transiently reduced the level of Complex IV. A significant increase in caspase 3 and ROS/RNS level but a decrease in to...
A small animal model that reproduces human immunodeficiency virus type 1 (HIV-1) pathogenesis may... more A small animal model that reproduces human immunodeficiency virus type 1 (HIV-1) pathogenesis may allow modeling of new therapeutic strategies in ways not approachable in mononuclear cell culture. We find that, as in humans, combination antiretroviral therapy (ART) in humanized (hu-) Rag2−/−γc−/− mice allows suppression of viremia below the limits of detection and recovery of CD4+ cells, while interruption of ART results in viral rebound and renewed loss of CD4+ T cells. Failure of ART in infected mice is associated with the appearance of drug resistance mutations. The hu-Rag2−/−γc−/− mouse may therefore facilitate testing of novel approaches to HIV replication and persistence.
Given the scope of the human immunodeficiency virus (HIV) pandemic, millions of people will be in... more Given the scope of the human immunodeficiency virus (HIV) pandemic, millions of people will be in need of chronic antiretroviral therapy (ART) for decades into the future. It is hoped that progress in prevention of HIV infection can be made, but there have been few successes in this effort thus far. At the same time, lifelong ART presents formidable problems. Therefore, while research must continue on improvements in prevention and treatment, future HIV research should now also seek to develop temporally contained therapies capable of eradicating HIV infection. This review will explore what is known about the mechanisms that restrain HIV expression and result in persistent, latent proviral infection, and what these mechanisms tell us about potential approaches towards eradication of HIV infection.
The formation of a latent reservoir of Human Immunodeficiency Virus (HIV†) infection hidden from ... more The formation of a latent reservoir of Human Immunodeficiency Virus (HIV†) infection hidden from immune clearance remains a significant obstacle to approaches to eradicate HIV infection. Towards an understanding of the mechanisms of HIV persistence, there is a growing body of work implicating epigenetic regulation of chromatin in establishment and maintenance of this latent reservoir. Here we discuss recent advances in the field of chromatin regulation, specifically in our understanding of the histone code, and how these discoveries relate to our current knowledge of the chromatin mechanisms linked to HIV transcriptional repression and the reversal of latency. We also examine mechanisms unexplored in the context of HIV latency and briefly discuss current therapies aimed at the induction of proviral expression within latently infected cells. We aim to emphasize that a greater understanding of the epigenetic mechanisms which govern HIV latency could lead to new therapeutic targets for...
The intact proviral DNA assay (IPDA) and quadruplex PCR (Q4PCR) represent major advances in accur... more The intact proviral DNA assay (IPDA) and quadruplex PCR (Q4PCR) represent major advances in accurately quantifying and characterizing the replication-competent HIV reservoir. This study compares the two novel approaches for measuring intact HIV proviral DNA in samples from 39 antiretroviral therapy (ART)-suppressed people living with HIV, thereby informing ongoing efforts to deplete the HIV reservoir in cure-related trials.
HIV persists within the body despite successful suppression of virus replication with antiretrovi... more HIV persists within the body despite successful suppression of virus replication with antiretroviral therapy (ART). HIV lurks in latent and active reservoirs, leading to rebound of virus spread if ART is interrupted. The latent HIV reservoir is a natural consequence of the life cycle of HIV, with integration of HIV into the genomes of cells that are or later enter the resting state, resulting in transcriptionally quiescent provirus. Resting CD4 T cells comprise the majority of the latent reservoir, although new evidence points to additional, smaller cellular reservoirs of latent HIV. An alternate, so-called active reservoir of HIV also exists within cells such as those found the B cell follicle of lymph nodes, where expression of HIV RNA can be found, again despite the full suppression of viremia and viral replication. Multiple factors such as the degree of virus exposure, timing of ART, and host factors can influence the size and characteristics of the HIV reservoir. Constructing effective strategies for HIV eradication and measuring their impact will require a sophisticated knowledge of the HIV reservoir.
The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome-rel... more The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome-related coronavirus-2 (SARS-CoV-2) has now caused over 2 million deaths worldwide and continues to expand. Currently, much is unknown about functionally neutralizing human antibody responses and durability to SARS-CoV-2. Using convalescent sera collected from 101 COVID-19 recovered individuals 21-212 days after symptom onset with forty-eight additional longitudinal samples, we measured functionality and durability of serum antibodies. We also evaluated associations between individual demographic and clinical parameters with functional neutralizing antibody responses to COVID-19. We found robust antibody durability out to six months, as well as significant positive associations with the magnitude of the neutralizing antibody response and male sex. We also show that SARS-CoV-2 convalescent neutralizing antibodies are higher in individuals with cardio-metabolic comorbidities.SignificanceIn thi...
The most significant barrier to an HIV-1 cure is the existence of the latently infected viral res... more The most significant barrier to an HIV-1 cure is the existence of the latently infected viral reservoir that gives rise to rebound viremia upon cessation of ART. Here, we tested a novel combination approach of latency reversal with AZD5582 and clearance with bispecific HIVxCD3 DART molecules in SHIV.C.CH505-infected, ART-suppressed rhesus macaques. We demonstrate that the DART molecules were not capable of clearing infected cells in vivo , attributed to the lack of quantifiable latency reversal in this model with low levels of persistent SHIV DNA prior to intervention as well as DART molecule immunogenicity.
Mitochondrial toxicity (Mito-Tox) risk has increased due to the administration of several classes... more Mitochondrial toxicity (Mito-Tox) risk has increased due to the administration of several classes of drugs, particularly some life-long antiretroviral drugs for HIV+ individuals. However, no suitable in vitro assays are available to test long-term Mito-Tox (≥4 weeks). The goal of this study is to develop a 3D spheroid system of human primary urine-derived stem cells (USC) for the prediction of drug-induced delayed Mito-Tox. The cytotoxicity and Mito-Tox were assessed in 3D USC spheroids 4 weeks after treatment with antiretroviral drugs: zalcitabine (ddC; 0.1, 1 and 10 µM), tenofovir (TFV; 3, 30 and 300 µM) or Raltegravir (RAL; 2, 20 and 200 µM). Rotenone (RTNN, 10 µM) and 0.1% DMSO served as positive and negative controls. Despite only mild cytotoxicity, ddC significantly inhibited the expression of oxidative phosphorylation enzyme Complexes I, III, and IV; and RAL transiently reduced the level of Complex IV. A significant increase in caspase 3 and ROS/RNS level but a decrease in to...
A small animal model that reproduces human immunodeficiency virus type 1 (HIV-1) pathogenesis may... more A small animal model that reproduces human immunodeficiency virus type 1 (HIV-1) pathogenesis may allow modeling of new therapeutic strategies in ways not approachable in mononuclear cell culture. We find that, as in humans, combination antiretroviral therapy (ART) in humanized (hu-) Rag2−/−γc−/− mice allows suppression of viremia below the limits of detection and recovery of CD4+ cells, while interruption of ART results in viral rebound and renewed loss of CD4+ T cells. Failure of ART in infected mice is associated with the appearance of drug resistance mutations. The hu-Rag2−/−γc−/− mouse may therefore facilitate testing of novel approaches to HIV replication and persistence.
Given the scope of the human immunodeficiency virus (HIV) pandemic, millions of people will be in... more Given the scope of the human immunodeficiency virus (HIV) pandemic, millions of people will be in need of chronic antiretroviral therapy (ART) for decades into the future. It is hoped that progress in prevention of HIV infection can be made, but there have been few successes in this effort thus far. At the same time, lifelong ART presents formidable problems. Therefore, while research must continue on improvements in prevention and treatment, future HIV research should now also seek to develop temporally contained therapies capable of eradicating HIV infection. This review will explore what is known about the mechanisms that restrain HIV expression and result in persistent, latent proviral infection, and what these mechanisms tell us about potential approaches towards eradication of HIV infection.
The formation of a latent reservoir of Human Immunodeficiency Virus (HIV†) infection hidden from ... more The formation of a latent reservoir of Human Immunodeficiency Virus (HIV†) infection hidden from immune clearance remains a significant obstacle to approaches to eradicate HIV infection. Towards an understanding of the mechanisms of HIV persistence, there is a growing body of work implicating epigenetic regulation of chromatin in establishment and maintenance of this latent reservoir. Here we discuss recent advances in the field of chromatin regulation, specifically in our understanding of the histone code, and how these discoveries relate to our current knowledge of the chromatin mechanisms linked to HIV transcriptional repression and the reversal of latency. We also examine mechanisms unexplored in the context of HIV latency and briefly discuss current therapies aimed at the induction of proviral expression within latently infected cells. We aim to emphasize that a greater understanding of the epigenetic mechanisms which govern HIV latency could lead to new therapeutic targets for...
The intact proviral DNA assay (IPDA) and quadruplex PCR (Q4PCR) represent major advances in accur... more The intact proviral DNA assay (IPDA) and quadruplex PCR (Q4PCR) represent major advances in accurately quantifying and characterizing the replication-competent HIV reservoir. This study compares the two novel approaches for measuring intact HIV proviral DNA in samples from 39 antiretroviral therapy (ART)-suppressed people living with HIV, thereby informing ongoing efforts to deplete the HIV reservoir in cure-related trials.
HIV persists within the body despite successful suppression of virus replication with antiretrovi... more HIV persists within the body despite successful suppression of virus replication with antiretroviral therapy (ART). HIV lurks in latent and active reservoirs, leading to rebound of virus spread if ART is interrupted. The latent HIV reservoir is a natural consequence of the life cycle of HIV, with integration of HIV into the genomes of cells that are or later enter the resting state, resulting in transcriptionally quiescent provirus. Resting CD4 T cells comprise the majority of the latent reservoir, although new evidence points to additional, smaller cellular reservoirs of latent HIV. An alternate, so-called active reservoir of HIV also exists within cells such as those found the B cell follicle of lymph nodes, where expression of HIV RNA can be found, again despite the full suppression of viremia and viral replication. Multiple factors such as the degree of virus exposure, timing of ART, and host factors can influence the size and characteristics of the HIV reservoir. Constructing effective strategies for HIV eradication and measuring their impact will require a sophisticated knowledge of the HIV reservoir.
The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome-rel... more The coronavirus disease 2019 (COVID-19) pandemic, caused by severe acute respiratory syndrome-related coronavirus-2 (SARS-CoV-2) has now caused over 2 million deaths worldwide and continues to expand. Currently, much is unknown about functionally neutralizing human antibody responses and durability to SARS-CoV-2. Using convalescent sera collected from 101 COVID-19 recovered individuals 21-212 days after symptom onset with forty-eight additional longitudinal samples, we measured functionality and durability of serum antibodies. We also evaluated associations between individual demographic and clinical parameters with functional neutralizing antibody responses to COVID-19. We found robust antibody durability out to six months, as well as significant positive associations with the magnitude of the neutralizing antibody response and male sex. We also show that SARS-CoV-2 convalescent neutralizing antibodies are higher in individuals with cardio-metabolic comorbidities.SignificanceIn thi...
The most significant barrier to an HIV-1 cure is the existence of the latently infected viral res... more The most significant barrier to an HIV-1 cure is the existence of the latently infected viral reservoir that gives rise to rebound viremia upon cessation of ART. Here, we tested a novel combination approach of latency reversal with AZD5582 and clearance with bispecific HIVxCD3 DART molecules in SHIV.C.CH505-infected, ART-suppressed rhesus macaques. We demonstrate that the DART molecules were not capable of clearing infected cells in vivo , attributed to the lack of quantifiable latency reversal in this model with low levels of persistent SHIV DNA prior to intervention as well as DART molecule immunogenicity.
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Papers by David Margolis