Biology subjects

Setua, S.

Publications and source records attributed to Setua, S..

3 recordsLinked to original sources

bioRxiv2023

Transmission of highly virulent CXCR4 tropic HIV-1 through the mucosal route in an individual with a wild-type CCR5 genotype

Nearly all transmitted/founder (T/F) HIV-1 are CCR5 (R5)-tropic. While previous evidence suggested that CXCR4 (X4)-tropic HIV-1 are transmissible, detection was not at the earliest stages of acute infection. Here, we identified an X4-tropic T/F HIV-1 in a participant in acute infection cohort. Coreceptor assays demonstrated that this T/F virus is strictly CXCR4 tropic. The participant experienced significantly faster CD4 depletion compared with R5 virus infected participants in the same cohort. Naive and central memory CD4 subsets declined faster than effector and transitional memory subsets. All CD4 subsets, including naive, were productively infected. Increased CD4+ T cell activation was observed over time. This X4-tropic T/F virus is resistant to broadly neutralizing antibodies (bNAbs) targeting V1/V2 and V3 regions. These findings demonstrate that X4-tropic HIV-1 is transmissible through the mucosal route in people with the wild-type CCR5 genotype and have implications for understanding the transmissibility and immunopathogenesis of X4-tropic HIV-1.

microbiology↗

bioRxiv2023

Tracking coreceptor switch of the transmitted/founder HIV-1 identifies co-evolution of HIV-1 antigenicity, coreceptor usage and CD4 subset targeting

The CCR5 (R5) to CXCR4 (X4) coreceptor switch in natural HIV-1 infection is associated with faster progression to AIDS, but the underlying mechanisms remain unclear. The difficulty in capturing the earliest moment of coreceptor switch in vivo limits our understanding of this phenomenon. Here, by tracking the evolution of the transmitted/founder (T/F) HIV-1 in a prospective cohort of individuals at risk for HIV-1 infection identified very early in acute infection, we investigated this process with high resolution. The earliest X4 variants evolved from the R5 tropic T/F strains. Strong X4 usage can be conferred by a single mutation. The mutations responsible for coreceptor switch can confer escape to neutralization and drive X4 variants to replicate mainly in the central memory and naive CD4+ T cells. We propose a novel concept to explain the co-evolution of virus antigenicity and entry tropism termed "escape by shifting". This concept posits that for viruses with receptor or coreceptor flexibility, entry tropism alteration represents a mechanism of immune evasion in vivo.

microbiology↗

bioRxiv2022

Mechanical Stimuli such as Shear Stress and Piezo1 Stimulation Generate Red Blood Cell Extracellular Vesicles

Circulating red blood cell extracellular vesicles (RBC-EVs) are a promising biomarker for vascular health. However, generating, isolating, and characterizing physiologically relevant RBC-EVs with sufficient yield and purity for biological studies is non-trivial. Here, we present and rigorously characterize an in vitro model to mimic RBC-EV production during shear stress via mechanosensitive piezo1 ion channel stimulation. We optimize our RBC-EV isolation protocol to minimize hemolysis, maximize RBC-EV yield and purity, and improve the ease of EV characterization. RBC-EV purity was measured by quantifying protein (e.g., particles/g), large particle (e.g., protein aggregates), and platelet EV contamination. This study compared RBC-EV isolation performance using membrane-based affinity (e.g., exoEasy), ultrafiltration (e.g., Amicon Ultra-15), and ultracentrifugation, with and without size exclusion chromatography purification. We found that treating 6% hematocrit with 10 M piezo1-agonist yoda1 for 30 minutes and isolating RBC-EVs using ultracentrifugation minimized RBC hemolysis and maximized RBC-EV yield (~1012 particles/mL) and purity, provided the most consistent RBC-EV preparations, and improved ease of RBC-EV characterization. Our pressure myography experiments suggest that co-isolated protein contaminants, but not piezo1 RBC-EVs, induce rapid mouse carotid artery vasodilation. These results underscore the importance of characterizing EV purity for biological experiments. The standardized methods outlined here enable mechanistic studies of how RBC-EVs generated in physiological flow affect vascular response.

bioengineering↗