Biology subjects

Cardozo-Ojeda, E. F.

Publications and source records attributed to Cardozo-Ojeda, E. F..

3 recordsLinked to original sources

bioRxiv2023

Hepatitis delta virus RNA decline post inoculation in human NTCP transgenic mice is biphasic

Background and AimsChronic infection with hepatitis B and hepatitis delta viruses (HDV) is considered the most serious form of viral hepatitis due to more severe manifestations of and accelerated progression to liver fibrosis, cirrhosis, and hepatocellular carcinoma. There is no FDA-approved treatment for HDV and current interferon-alpha treatment is suboptimal. We characterized early HDV kinetics post inoculation and incorporated mathematical modeling to provide insights into host-HDV dynamics. MethodsWe analyzed HDV RNA serum viremia in 192 immunocompetent (C57BL/6) and immunodeficient (NRG) mice that did or did not transgenically express the HDV receptor - human sodium taurocholate co-transporting peptide (hNTCP). ResultsKinetic analysis indicates an unanticipated biphasic decline consisting of a sharp first-phase and slower second-phase decline regardless of immunocompetence. HDV decline after re-inoculation again followed a biphasic decline; however, a steeper second-phase HDV decline was observed in NRG-hNTCP mice compared to NRG mice. HDV-entry inhibitor bulevirtide administration and HDV re-inoculation indicated that viral entry and receptor saturation are not major contributors to clearance, respectively. The biphasic kinetics can be mathematically modeled by assuming the existence of a non-specific binding compartment with a constant on/off-rate and the steeper second-phase decline by a loss of bound virus that cannot be returned as free virus to circulation. The model predicts that free HDV is cleared with a half-life of 18 minutes (standard error, SE: 2.4), binds to non-specific cells with a rate of 0.06 hour-1 (SE: 0.03), and returns as free virus with a rate of 0.23 hour-1 (SE: 0.03). ConclusionsUnderstanding early HDV-host kinetics will inform pre-clinical therapeutic kinetic studies on how the efficacy of anti-HDV therapeutics can be affected by early kinetics of viral decline. LAY SUMMARYThe persistence phase of HDV infection has been studied in some animal models, however, the early kinetics of HDV in vivo is incompletely understood. In this study, we characterize an unexpectedly HDV biphasic decline post inoculation in immunocompetent and immunodeficient mouse models and use mathematical modeling to provide insights into HDV-host dynamics. Understanding the kinetics of viral clearance in the blood can aid pre-clinical development and testing models for anti-HDV therapeutics.

microbiology↗

bioRxiv2020

Mathematical modeling explains differential SARS CoV-2 kinetics in lung and nasal passages in remdesivir treated rhesus macaques

Remdesivir was recently demonstrated to decrease recovery time in hospitalized patients with SARS-CoV-2 infection. In rhesus macaques, early initiation of remdesivir therapy prevented pneumonia and lowered viral loads in the lung, but viral loads increased in the nasal passages five days after therapy. We developed mathematical models to explain these results. We identified that 1) drug potency is slightly higher in nasal passages than in lungs, 2) viral load decrease in lungs relative to nasal passages during therapy because of infection-dependent generation of refractory cells in the lung, 3) incomplete drug potency in the lung that decreases viral loads even slightly may allow substantially less lung damage, and 4) increases in nasal viral load may occur due to a slight blunting of peak viral load and subsequent decrease of the intensity of the innate immune response, as well as a lack of refractory cells. We also hypothesize that direct inoculation of the trachea in rhesus macaques may not recapitulate natural infection as lung damage occurs more abruptly in this model than in human infection. We demonstrate with sensitivity analysis that a drug with higher potency could completely suppress viral replication and lower viral loads abruptly in the nasal passages as well as the lung. One Sentence SummaryWe developed a mathematical model to explain why remdesivir has a greater antiviral effect on SARS CoV-2 in lung versus nasal passages in rhesus macaques.

microbiology↗

bioRxiv2019

Thresholds for post-rebound viral control after CCR5 gene-edited autologous hematopoietic cell transplantation

Autologous, CCR5 gene-edited hematopoietic stem and progenitor cell (HSPC) transplantation is a promising strategy for achieving HIV remission. However, only a fraction of HSPCs can be edited ex vivo to provide protection against infection prior to autologous transplantation. The optimal transplantation conditions for achieving viral control in the absence of suppressive antiretroviral therapy (ART) are still unknown. We analyzed data from SHIV-1157ipd3N4-infected juvenile pig-tailed macaques that underwent autologous HSPC transplantation with and without CCR5 gene editing. We developed a mathematical model that recapitulates reconstitution of T cell subset counts and SHIV plasma viral loads in control and transplanted macaques. The model predicts that viral control can be obtained following ART treatment interruption (ATI) when: 1) levels of transplanted HSPCs are at least 10-fold higher than residual endogenous HSPCs after total body irradiation and 2) the fraction of protected HSPCs in the transplant achieves a threshold (73%-90%) sufficient to overcome transplantation-dependent loss of SHIV immunity. Under these conditions, if ATI is withheld until transplanted gene-modified cells engraft and reconstitute to a steady state, then spontaneous viral control is projected to occur immediately. Our results support strategies that 1) increase stem cell dose, 2) enhance potency of conditioning regimen, 3) elevate fraction of gene modified SHIV-resistant cells, 4) extend periods between HSPC transplantation and ATI with tracking of CD4+CCR5- cell recovery and / or 5) augment anti-SHIV immunity to achieve sustained SHIV remission. One Sentence SummaryAutologous transplantation of {Delta}CCR5 HSPCs may induce post-ATI SHIV control when the gene-edited cell dose is sufficient to overcome SHIV immunity loss.

microbiology↗