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Ciupe SM, Conway JM. Incorporating Intracellular Processes in Virus Dynamics Models. Microorganisms 2024; 12:900. [PMID: 38792730 PMCID: PMC11124127 DOI: 10.3390/microorganisms12050900] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2024] [Revised: 04/25/2024] [Accepted: 04/26/2024] [Indexed: 05/26/2024] Open
Abstract
In-host models have been essential for understanding the dynamics of virus infection inside an infected individual. When used together with biological data, they provide insight into viral life cycle, intracellular and cellular virus-host interactions, and the role, efficacy, and mode of action of therapeutics. In this review, we present the standard model of virus dynamics and highlight situations where added model complexity accounting for intracellular processes is needed. We present several examples from acute and chronic viral infections where such inclusion in explicit and implicit manner has led to improvement in parameter estimates, unification of conclusions, guidance for targeted therapeutics, and crossover among model systems. We also discuss trade-offs between model realism and predictive power and highlight the need of increased data collection at finer scale of resolution to better validate complex models.
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Affiliation(s)
- Stanca M. Ciupe
- Department of Mathematics, Virginia Polytechnic Institute and State University, Blacksburg, VA 24060, USA
| | - Jessica M. Conway
- Department of Mathematics and Center for Infectious Disease Dynamics, Penn State University, State College, PA 16802, USA
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2
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Nande A, Hill AL. The risk of drug resistance during long-acting antimicrobial therapy. Proc Biol Sci 2022; 289:20221444. [PMID: 36350211 PMCID: PMC9653236 DOI: 10.1098/rspb.2022.1444] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The emergence of drug resistance during antimicrobial therapy is a major global health problem, especially for chronic infections like human immunodeficiency virus, hepatitis B and C, and tuberculosis. Sub-optimal adherence to long-term treatment is an important contributor to resistance risk. New long-acting drugs are being developed for weekly, monthly or less frequent dosing to improve adherence, but may lead to long-term exposure to intermediate drug levels. In this study, we analyse the effect of dosing frequency on the risk of resistance evolving during time-varying drug levels. We find that long-acting therapies can increase, decrease or have little effect on resistance, depending on the source (pre-existing or de novo) and degree of resistance, and rates of drug absorption and clearance. Long-acting therapies with rapid drug absorption, slow clearance and strong wild-type inhibition tend to reduce resistance caused by partially resistant strains in the early stages of treatment even if they do not improve adherence. However, if subpopulations of microbes persist and can reactivate during sub-optimal treatment, longer-acting therapies may substantially increase the resistance risk. Our results show that drug kinetics affect selection for resistance in a complicated manner, and that pathogen-specific models are needed to evaluate the benefits of new long-acting therapies.
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Affiliation(s)
- Anjalika Nande
- Program for Evolutionary Dynamics, Harvard University, Cambridge, MA 02138, USA
- Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD 21218, USA
| | - Alison L. Hill
- Program for Evolutionary Dynamics, Harvard University, Cambridge, MA 02138, USA
- Institute for Computational Medicine, Johns Hopkins University, Baltimore, MD 21218, USA
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Bergstresser S, Kulpa DA. TGF-β Signaling Supports HIV Latency in a Memory CD4+ T Cell Based In Vitro Model. Methods Mol Biol 2022; 2407:69-79. [PMID: 34985658 DOI: 10.1007/978-1-0716-1871-4_6] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
During antiretroviral therapy (ART), HIV-1 persists as a latent reservoir in CD4+ T cell subsets in central (TCM), transitional (TTM) and effector memory (TEM) CD4+ T cells. Understanding the mechanisms that support HIV-1 latency in each of these subsets is essential to the identification of cure strategies to eliminate them. Due to the very low frequency of latently infected cells in vivo, model systems that can accurately reflect the heterogenous population of HIV-1 infected cells are a critical component in HIV cure discoveries. Here, we describe a novel primary cell-based model of HIV-1 latency that recapitulates the complex dynamics of the establishment and maintenance of the latent reservoir in different memory T cell subsets. The latency and reversion assay (LARA ) culture conditions uniquely retain phenotypically and transcriptionally distinct memory CD4+ T cell subsets that allow in a single assay to assess LRA activity in each memory subset and differential examination of the dynamics of HIV latency reversal.
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Affiliation(s)
- Sydney Bergstresser
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, and Yerkes National Primate Research Center, Atlanta, GA, USA
| | - Deanna A Kulpa
- Department of Pathology and Laboratory Medicine, Emory University School of Medicine, and Yerkes National Primate Research Center, Atlanta, GA, USA.
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DAŞBAŞI B. Stability analysis of the hiv model through incommensurate fractional-order nonlinear system. CHAOS, SOLITONS, AND FRACTALS 2020; 137:109870. [PMID: 32395039 PMCID: PMC7211765 DOI: 10.1016/j.chaos.2020.109870] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 05/03/2020] [Accepted: 05/04/2020] [Indexed: 06/11/2023]
Abstract
In this study, it is employed a new model of HIV infection in the form of incommensurate fractional differential equations systems involving the Caputo fractional derivative. Existence of the model's equilibrium points has been investigated. According to some special cases of the derivative-orders in the proposed model, the asymptotic stability of the infection-free equilibrium and endemic equilibrium has been proved under certain conditions. These stability conditions related to the derivative-orders depend on not only the basic reproduction rate frequently emphasized in the literature but also the newly obtained conditions in this study. Qualitative analysis results were complemented by numerical simulations in Matlab, illustrating the obtained stability result.
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Affiliation(s)
- Bahatdin DAŞBAŞI
- Kayseri University, Faculty of Applied Sciences, TR-38039, Kayseri, Turkey
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Gorska AM, Eugenin EA. The Glutamate System as a Crucial Regulator of CNS Toxicity and Survival of HIV Reservoirs. Front Cell Infect Microbiol 2020; 10:261. [PMID: 32670889 PMCID: PMC7326772 DOI: 10.3389/fcimb.2020.00261] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Accepted: 05/04/2020] [Indexed: 12/11/2022] Open
Abstract
Glutamate (Glu) is the most abundant excitatory neurotransmitter in the central nervous system (CNS). HIV-1 and viral proteins compromise glutamate synaptic transmission, resulting in poor cell-to-cell signaling and bystander toxicity. In this study, we identified that myeloid HIV-1-brain reservoirs survive in Glu and glutamine (Gln) as a major source of energy. Thus, we found a link between synaptic compromise, metabolomics of viral reservoirs, and viral persistence. In the current manuscript we will discuss all these interactions and the potential to achieve eradication and cure using this unique metabolic profile.
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Affiliation(s)
- Anna Maria Gorska
- Department of Neuroscience, Cell Biology, and Anatomy, The University of Texas Medical Branch, Galveston, TX, United States
| | - Eliseo A Eugenin
- Department of Neuroscience, Cell Biology, and Anatomy, The University of Texas Medical Branch, Galveston, TX, United States
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Pinkevych M, Fennessey CM, Cromer D, Reid C, Trubey CM, Lifson JD, Keele BF, Davenport MP. Predictors of SIV recrudescence following antiretroviral treatment interruption. eLife 2019; 8:e49022. [PMID: 31650954 PMCID: PMC6917497 DOI: 10.7554/elife.49022] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Accepted: 10/24/2019] [Indexed: 12/26/2022] Open
Abstract
There is currently a need for proxy measures of the HIV rebound competent reservoir (RCR) that can predict viral rebound after combined antiretroviral treatment (cART) interruption. In this study, macaques infected with a barcoded SIVmac239 virus received cART beginning between 4- and 27 days post-infection, leading to the establishment of different levels of viral dissemination and persistence. Later treatment initiation led to higher SIV DNA levels maintained during treatment, which was significantly associated with an increased frequency of SIV reactivation and production of progeny capable of causing rebound viremia following treatment interruption. However, a 100-fold increase in SIV DNA in PBMCs was associated with only a 2-fold increase in the frequency of reactivation. These data suggest that the RCR can be established soon after infection, and that a large fraction of persistent viral DNA that accumulates after this time makes relatively little contribution to viral rebound.
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Affiliation(s)
- Mykola Pinkevych
- Infection Analytics ProgramKirby Institute for Infection and Immunity, UNSW AustraliaSydneyAustralia
| | - Christine M Fennessey
- AIDS and Cancer Virus ProgramFrederick National Laboratory for Cancer ResearchFrederickUnited States
| | - Deborah Cromer
- Infection Analytics ProgramKirby Institute for Infection and Immunity, UNSW AustraliaSydneyAustralia
| | - Carolyn Reid
- AIDS and Cancer Virus ProgramFrederick National Laboratory for Cancer ResearchFrederickUnited States
| | - Charles M Trubey
- AIDS and Cancer Virus ProgramFrederick National Laboratory for Cancer ResearchFrederickUnited States
| | - Jeffrey D Lifson
- AIDS and Cancer Virus ProgramFrederick National Laboratory for Cancer ResearchFrederickUnited States
| | - Brandon F Keele
- AIDS and Cancer Virus ProgramFrederick National Laboratory for Cancer ResearchFrederickUnited States
| | - Miles P Davenport
- Infection Analytics ProgramKirby Institute for Infection and Immunity, UNSW AustraliaSydneyAustralia
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Sadowski I, Hashemi FB. Strategies to eradicate HIV from infected patients: elimination of latent provirus reservoirs. Cell Mol Life Sci 2019; 76:3583-3600. [PMID: 31129856 PMCID: PMC6697715 DOI: 10.1007/s00018-019-03156-8] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2019] [Revised: 04/29/2019] [Accepted: 05/20/2019] [Indexed: 02/06/2023]
Abstract
35 years since identification of HIV as the causative agent of AIDS, and 35 million deaths associated with this disease, significant effort is now directed towards the development of potential cures. Current anti-retroviral (ART) therapies for HIV/AIDS can suppress virus replication to undetectable levels, and infected individuals can live symptom free so long as treatment is maintained. However, removal of therapy allows rapid re-emergence of virus from a highly stable reservoir of latently infected cells that exist as a barrier to elimination of the infection with current ART. Prospects of a cure for HIV infection are significantly encouraged by two serendipitous cases where individuals have entered remission following stem cell transplantation from compatible HIV-resistant donors. However, development of a routine cure that could become available to millions of infected individuals will require a means of specifically purging cells harboring latent HIV, preventing replication of latent provirus, or destruction of provirus genomes by gene editing. Elimination of latently infected cells will require a means of exposing this population, which may involve identification of a natural specific biomarker or therapeutic intervention to force their exposure by reactivation of virus expression. Accordingly, the proposed "Shock and Kill" strategy involves treatment with latency-reversing agents (LRA) to induce HIV provirus expression thus exposing these cells to killing by cellular immunity or apoptosis. Current efforts to enable this strategy are directed at developing improved combinations of LRA to produce broad and robust induction of HIV provirus and enhancing the elimination of cells where replication has been reactivated by targeted immune modulation. Alternative strategies may involve preventing re-emergence virus from latently infected cells by "Lock and Block" intervention, where transcription of provirus is inhibited to prevent virus spread or disruption of the HIV provirus genome by genome editing.
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Affiliation(s)
- Ivan Sadowski
- Department of Biochemistry and Molecular Biology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada.
| | - Farhad B Hashemi
- Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
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Abstract
The interplay between immune response and HIV is intensely studied via mathematical modeling, with significant insights but few direct answers. In this short review, we highlight advances and knowledge gaps across different aspects of immunity. In particular, we identify the innate immune response and its role in priming the adaptive response as ripe for modeling. The latter have been the focus of most modeling studies, but we also synthesize key outstanding questions regarding effector mechanisms of cellular immunity and development of broadly neutralizing antibodies. Thus far, most modeling studies aimed to infer general immune mechanisms; we foresee that significant progress will be made next by detailed quantitative fitting of models to data, and prediction of immune responses.
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Affiliation(s)
- Jessica M Conway
- Department of Mathematics and Center for Infectious Disease Dynamics, Pennsylvania State University, University Park PA 16802, USA
| | - Ruy M Ribeiro
- Laboratorio de Biomatematica, Faculdade de Medicina da Universidade de Lisboa, Portugal and Theoretical Biology and Biophysics, Los Alamos National Laboratory, Los Alamos, NM 87545, USA
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Anderson EM, Maldarelli F. The role of integration and clonal expansion in HIV infection: live long and prosper. Retrovirology 2018; 15:71. [PMID: 30352600 PMCID: PMC6199739 DOI: 10.1186/s12977-018-0448-8] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2018] [Accepted: 09/15/2018] [Indexed: 02/07/2023] Open
Abstract
Integration of viral DNA into the host genome is a central event in the replication cycle and the pathogenesis of retroviruses, including HIV. Although most cells infected with HIV are rapidly eliminated in vivo, HIV also infects long-lived cells that persist during combination antiretroviral therapy (cART). Cells with replication competent HIV proviruses form a reservoir that persists despite cART and such reservoirs are at the center of efforts to eradicate or control infection without cART. The mechanisms of persistence of these chronically infected long-lived cells is uncertain, but recent research has demonstrated that the presence of the HIV provirus has enduring effects on infected cells. Cells with integrated proviruses may persist for many years, undergo clonal expansion, and produce replication competent HIV. Even proviruses with defective genomes can produce HIV RNA and may contribute to ongoing HIV pathogenesis. New analyses of HIV infected cells suggest that over time on cART, there is a shift in the composition of the population of HIV infected cells, with the infected cells that persist over prolonged periods having proviruses integrated in genes associated with regulation of cell growth. In several cases, strong evidence indicates the presence of the provirus in specific genes may determine persistence, proliferation, or both. These data have raised the intriguing possibility that after cART is introduced, a selection process enriches for cells with proviruses integrated in genes associated with cell growth regulation. The dynamic nature of populations of cells infected with HIV during cART is not well understood, but is likely to have a profound influence on the composition of the HIV reservoir with critical consequences for HIV eradication and control strategies. As such, integration studies will shed light on understanding viral persistence and inform eradication and control strategies. Here we review the process of HIV integration, the role that integration plays in persistence, clonal expansion of the HIV reservoir, and highlight current challenges and outstanding questions for future research.
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Affiliation(s)
| | - Frank Maldarelli
- HIV Dynamics and Replication Program, NCI, NIH, Frederick, MD, 21702, USA.
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Hill AL, Rosenbloom DIS, Nowak MA, Siliciano RF. Insight into treatment of HIV infection from viral dynamics models. Immunol Rev 2018; 285:9-25. [PMID: 30129208 PMCID: PMC6155466 DOI: 10.1111/imr.12698] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The odds of living a long and healthy life with HIV infection have dramatically improved with the advent of combination antiretroviral therapy. Along with the early development and clinical trials of these drugs, and new field of research emerged called viral dynamics, which uses mathematical models to interpret and predict the time-course of viral levels during infection and how they are altered by treatment. In this review, we summarize the contributions that virus dynamics models have made to understanding the pathophysiology of infection and to designing effective therapies. This includes studies of the multiphasic decay of viral load when antiretroviral therapy is given, the evolution of drug resistance, the long-term persistence latently infected cells, and the rebound of viremia when drugs are stopped. We additionally discuss new work applying viral dynamics models to new classes of investigational treatment for HIV, including latency-reversing agents and immunotherapy.
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Affiliation(s)
- Alison L. Hill
- Program for Evolutionary DynamicsHarvard UniversityCambridgeMassachusetts
| | - Daniel I. S. Rosenbloom
- Department of PharmacokineticsPharmacodynamics, & Drug MetabolismMerck Research LaboratoriesKenilworthNew Jersey
| | - Martin A. Nowak
- Program for Evolutionary DynamicsHarvard UniversityCambridgeMassachusetts
| | - Robert F. Siliciano
- Department of MedicineJohns Hopkins University School of MedicineBaltimoreMaryland
- Howard Hughes Medical InstituteBaltimoreMaryland
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