Biology subjects

Pastorio, C.

Publications and source records attributed to Pastorio, C..

6 recordsLinked to original sources

bioRxiv2025

Retinol Binding Protein 4 reactivates latent HIV-1 via the JAK/STAT5 and JNK pathways

Reactivation of the latent viral reservoirs is crucial for a cure of HIV/AIDS. However, current latency reversing agents are inefficient and the endogenous factors that have the potential to reactivate HIV in vivo remain poorly understood. To identify natural activators of latent HIV-1, we screened a comprehensive peptide/protein library derived from human hemofiltrate, representing the entire blood peptidome, using J-Lat cell lines harboring transcriptionally silent HIV-1 GFP reporter viruses. Fractions potently reactivating HIV-1 from latency contained human Retinol Binding Protein 4 (RBP4), the carrier of retinol (vitamin A). We found that retinol-bound holo-RBP4 but not retinol-free apo-RBP4 strongly reactivates HIV-1 in a variety of latently infected T cell lines. Functional analysis revealed that this reactivation depends on the JAK/STAT5 and JNK pathways but does not require retinoic acid production. High levels of RBP4 were detected in plasma from both healthy individuals and people living with HIV-1. Physiological concentrations of RBP4 induced significant viral reactivation in latently infected cells from individuals on long-term antiretroviral therapy with undetectable viral loads. As a potent natural HIV-1 latency-reversing agent, RBP4 offers a novel approach to activating the latent reservoirs and bringing us closer to a cure.

immunology↗

bioRxiv2025

GPR15LG binds CXCR4 and synergistically modulates CXCL12-induced cell signaling and migration

GPR15LG, a chemokine-like ligand for the G-protein coupled receptor 15 (GPR15), is abundantly expressed in the gastrointestinal mucosa and inflamed skin. Emerging evidence suggests its involvement in inflammatory disorders and cancers. This study investigates the effects of GPR15LG on the signaling and downstream functions of C-X-C chemokine receptor type 4 (CXCR4), which plays a critical role in immune cell trafficking and cancer metastasis. The results demonstrate that GPR15LG binds to the orthosteric site of CXCR4, modulating downstream signaling in a context-dependent manner. Specifically, GPR15LG enhances CXCL12-mediated CXCR4 signaling synergistically, promoting wound healing and cell migration across various cell types, including CD4+ T cells and cancer cells. These findings underscore the role of GPR15LG in inflammation and metastasis, offering potential therapeutic avenues for CXCR4-mediated diseases. TeaserGPR15LG binds CXCR4 thereby modulating CXCL12/CXCR4 signaling and immune and cancer cell trafficking.

cell biology↗

bioRxiv2024

Attenuated replication and damaging effects of SARS-CoV-2 Omicron in an intestinal epithelial barrier model

Many COVID-19 patients suffer from gastrointestinal symptoms and impaired intestinal barrier function may play a key role in Long COVID. Despite its importance, the impact of SARS-CoV-2 on intestinal epithelia is poorly understood. To address this, we established an intestinal barrier model integrating epithelial Caco-2 cells, mucus-secreting HT29 cells and human Raji cells. This gut epithelial model allows efficient differentiation of Caco-2 cells into microfold-like cells, faithfully mimics intestinal barrier function, and is highly permissive to SARS-CoV-2 infection. Early strains of SARS-CoV-2 and the Delta variant replicated with high efficiency, severely disrupted barrier function, and depleted tight junction proteins, such as claudin-1, occludin and ZO-1. In comparison, Omicron subvariants also depleted ZO-1 from tight junctions but had fewer damaging effects on mucosal integrity and barrier function. Remdesivir and the TMPRSS2 inhibitor Camostat prevented SARS-CoV-2 replication and thus epithelial barrier damage, while the Cathepsin inhibitor E64d was ineffective. Our results support that SARS-CoV-2 disrupts intestinal barrier function but further suggest that circulating Omicron variants are less damaging than earlier viral strains.

immunology↗

bioRxiv2023

Traitor-virus-guided discovery of novel antiviral factors

Complex pathogen-host interactions govern the outcome of viral exposures but remain poorly understood because current methods to elucidate antiviral mechanisms are prone to artefacts and lack sensitivity. Here, we developed a virus-guided technology platform where the pathogen itself reveals its cellular opponents. To accomplish this, we engineered replication-competent HIV-1 expressing sgRNAs targeting potential antiviral genes in Cas9-expressing CD4+ T cells. Simultaneous analysis of HIV-1 constructs targeting >500 candidate genes revealed that sgRNAs against GRN, CIITA, EHMT2, CEACAM3, CC2D1B, RHOA and HMOX1 are strongly enriched over several rounds of replication. Overexpression and knock-out studies confirmed the antiretroviral activity of most factors but failed for some. Finally, we show that lack of the accessory nef gene increased enrichment of sgRNAs targeting SERINC5 and IFI16 demonstrating that this method allows identification of targets of accessory proteins. The versatile and effective HIV-guided CRISPR technology offers numerous possibilities for clarification of virus-host interactions and innate defense mechanisms.

microbiology↗

bioRxiv2023

Determinants of species-specific utilization of ACE2 by human and animal coronaviruses

Utilization of human ACE2 allowed several bat coronaviruses (CoVs), including the causative agent of COVID-19, to infect humans either directly or via intermediate hosts. Here, we analyzed the ability of Spike proteins from 24 human or animal CoVs to use ACE2 receptors across nine reservoir, potential intermediate and human hosts. We show that overall SARS-CoV-2 Omicron variants evolved more efficient ACE2 usage but mutation of R493Q in BA.5 Spike disrupts utilization of ACE2 from Greater horseshoe bats. Spikes from most CoVs showed species-specific differences in ACE2 usage, partly due to variations in ACE2 residues 31, 41 or 354. Mutation of T403R allowed the RaTG13 bat CoV Spike to use all ACE2 orthologs analysed for viral entry. Sera from COVID-19 vaccinated individuals neutralized the Spike proteins of a range of bat Sarbecoviruses. Our results define determinants of ACE2 receptor usage of diverse CoVs and suggest that COVID-19 vaccination may protect against future zoonoses of SARS-CoV-related bat viruses. HighlightsO_LIMutation of R493Q in BA.5 Spike disrupts utilization of ACE2 from Greater horseshoe bats C_LIO_LIVariations in ACE2 residues 31, 41 or 354 affect utilization by coronavirus Spike proteins C_LIO_LIResidue R403 in the Spike protein of bat coronavirus allow broad and effective ACE2 usage C_LIO_LISera from COVID-19 vaccinated individuals neutralize Spike proteins of bat Sarbecoviruses C_LI

molecular biology↗

bioRxiv2022

Determinants of Spike Infectivity, Processing and Neutralization in SARS-CoV-2 Omicron subvariants BA.1 and BA.2

The SARS-CoV-2 Omicron variant rapidly outcompeted other variants and currently dominates the COVID-19 pandemic. Its enhanced transmission, immune evasion and pathogenicity is thought to be driven by numerous mutations in the Omicron Spike protein. Here, we examined the impact of amino acid changes that are characteristic for the BA.1 and/or BA.2 Omicron lineages on Spike function, processing and susceptibility to neutralization. Individual mutations of S371F/L, S375F and T376A in the ACE2 receptor-binding domain as well as Q954H and N969K in the hinge region 1 impaired infectivity, while changes of G339D, D614G, N764K and L981F moderately enhanced it. Most mutations in the N-terminal region and the receptor binding domain reduced sensitivity of the Spike protein to neutralization by sera from individuals vaccinated with the BNT162b2 vaccine or therapeutic antibodies. Our results represent a systematic functional analysis of Omicron Spike adaptations that allowed this SARS-CoV-2 variant to overtake the current pandemic. HIGHLIGHTSO_LIS371F/L, S373P and S375F impair Spike function and revert in some BA. 1 isolates C_LIO_LIChanges of Q954H and N969K in HR1 reduce while L981F enhances S-mediated infection C_LIO_LIOmicron-specific mutations in the NTD and RBD of Spike reduce neutralization C_LIO_LIN440K, G446S, E484A and Q493K confer resistance to bamlanivimab or imdevimab C_LI

microbiology↗