Biology subjects

Santangelo, P.

Publications and source records attributed to Santangelo, P..

4 recordsLinked to original sources

bioRxiv2022

Ultrastructural characterization of a viral RNA and G-protein containing, membranous organelle formed in respiratory syncytial virus infected cells

Withdrawal statementThe authors have withdrawn their manuscript because since deposition of this preprint, they have become aware of the possibility that the findings reported may be an artefact. Carter et al. (J Struct Biol 2018 Jan;201(1):15-25. doi: 10.1016/j.jsb.2017.10.009) have reported that multilamellar bodies exhibit autofluorescence under cryogenic conditions. Thus, there is a possibility that stress induced by virus infection may stimulate formation of the features reported in this article, and autofluorescence, rather than specific labelling led them to identify the puncta as compartments containing RSV proteins or genomes. They are working to address these issues. Therefore, the authors do not wish this work to be cited as reference for the project. If you have any questions, please contact the corresponding author.

microbiology↗

bioRxiv2022

Blockade of TGF-β signaling reactivates HIV-1/SIV reservoirs and immune responses in vivo

Elevated levels of TGF-{beta}, a potent immunosuppressive factor, are present in HIV-1 infected individuals even after years of antiretroviral therapy (ART). TGF-{beta} plays a critical role in maintaining immune cells in a resting state by inhibiting cell activation and proliferation. Resting HIV-1 target cells represent one of the main cellular reservoirs after long term ART and the low inducibility of the latent provirus constitutes one of the major obstacles to "kick and kill" cure strategies. We hypothesized that releasing cells from TGF-{beta}-driven signaling would promote latency reversal. To test our hypothesis, we compared ex vivo models of HIV-1 latency reactivation with and without TGF-{beta} and a TGF-{beta} type 1 receptor (TGFBR1) inhibitor, galunisertib. We also tested the effect of galunisertib in SIV infected, ART treated macaques by monitoring SIV envelope (env) protein expression via PET/CT using the Cu64-anti gp120 Fab (7D3) probe, along with plasma and tissue viral loads (VL). Exogenous TGF-1{beta} reduced HIV-1 reactivation in U1 and ACH2 latency models. Galunisertib increased HIV-1 latency reversal both in ex vivo models and in PBMC from HIV-1 infected, cART treated aviremic donors. In vivo, oral galunisertib promoted increased SIV env protein total standardized uptake values (SUVtot) in PET/CT images of tissues (gut and lymph nodes) of 5 out of 7 aviremic, long-term ART-treated, SIV-infected, macaques. This increase correlated with an increase in SIV RNA in gut tissue. Two out of 7 animals also exhibited increases in plasma viral load. Higher anti-SIV T cell responses and anti-SIV env antibody titers were detected after galunisertib treatment in most animals. In summary, our data suggest that blocking TGF-{beta} signaling simultaneously increases retroviral reactivation events and enhances anti-SIV immune responses.

immunology↗

bioRxiv2021

In vivo mRNA delivery to virus-specific T cells by light-induced ligand exchange of MHC class I antigen-presenting nanoparticles

Simultaneous delivery of mRNA to multiple populations of antigen (Ag)-specific CD8+ T cells is challenging given the diversity of peptide epitopes and polymorphism of class I major histocompatibility complexes (MHCI). We developed Ag-presenting nanoparticles (APNs) for mRNA delivery using pMHCI molecules that were refolded with photocleavable peptides to allow rapid ligand exchange by UV light and site-specifically conjugated with a lipid tail for post-insertion into preformed mRNA lipid nanoparticles. Across different TCR transgenic mouse models (P14, OT-1, Pmel), UV-exchanged APNs bound and transfected their cognate Ag-specific CD8+ T cells equivalent to APNs produced using conventionally refolded pMHCI molecules. In mice infected with PR8 influenza, multiplexed delivery of UV-exchanged APNs against three immunodominant epitopes led to ~50% transfection of a VHH mRNA reporter in cognate Ag-specific CD8+ T cells. Our data shows that UV-mediated peptide exchange can be used to rapidly produce APNs for mRNA delivery to multiple populations of Ag-specific T cells in vivo. TeaserLight-induced rapid production of antigen-presenting nanoparticles for mRNA delivery to multiple virus-specific T cell populations.

bioengineering↗

bioRxiv2018

Synthetic mRNA expressed Cas13a mitigates RNA virus infections

The emergence of the CRISPR-Cas system as a technology has transformed our ability to modify nucleic acids. Prokaryotes evolved one member of this family, CRISPR-Cas effector, Cas13a, as an RNA-guided ribonuclease that protects them from invading bacteriophages. Here, we demonstrate that Cas13a can be programmed to target eukaryotic viral pathogens, influenza virus A (IVA) and human respiratory syncytial virus (hRSV) in human cells. We designed synthetic mRNA coding for Cas13a, which when guided by CRISPR RNAs (crRNA) to target influenza virus or hRSV RNA, significantly mitigates these infections both prophylactically, therapeutically, and over time. These data demonstrate a possible new class of synthetic mRNA-powered anti-viral interventions.\n\nOne Sentence SummarycrRNA guided Cas13a halts RNA virus infections

molecular biology↗