Biology subjects

MURIAUX, D.

Publications and source records attributed to MURIAUX, D..

7 recordsLinked to original sources

bioRxiv2025

Human pluripotent stem cell-derived bronchial airway organoids provide insights into differential innate immune and long-term responses to SARS-CoV-2 infection in healthy and COPD.

Respiratory infections are a major global health concern, as underscored by the COVID-19 pandemic. To better understand bronchial tissue responses to viral infection, we have developed a preclinical in vitro model mimicking the multiciliated airway epithelium, from induced pluripotent stem cell (iPSC) and cultured in an air-liquid interface (iALI). By using iPSCs reprogrammed from patients with chronic obstructive pulmonary disease (COPD), we successfully generated a fully differentiated and functional bronchial epithelium exhibiting key COPD features with goblet and basal cell hyperplasia and tissue inflammation. SARS-CoV-2 could infected and replicated for several weeks in both healthy and COPD models, with a recurrent peak at 3 days after infection. Infected iALI exhibited cilia destruction and increased mucus secretion. Innate immune response of different infected iALI reveals a differential expression of interferon-stimulated genes (ISGs) and pro-inflammatory cytokine secretion. Notably, COPD iALI displayed an earlier innate immune response to SARS-CoV-2 infection as compared to healthy iALI, suggesting a genetic susceptibility of COPD iALI towards inflammation induced by SARS-CoV-2 infection, and a less efficient response to antivirals. In conclusion, our study demonstrates that the iALI bronchial organoid model is a powerful tool for investigating bronchial tissue responses to long term respiratory viral infections, antivirals, and patients with COPD or other airway pathology. Grapical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=151 SRC="FIGDIR/small/662440v1_ufig1.gif" ALT="Figure 1"> View larger version (53K): org.highwire.dtl.DTLVardef@9e5ef7org.highwire.dtl.DTLVardef@16ccf60org.highwire.dtl.DTLVardef@a2b29dorg.highwire.dtl.DTLVardef@17c6f14_HPS_FORMAT_FIGEXP M_FIG C_FIG HighLightsO_LIhiPSC-derived COPD airway organoids C_LIO_LISARS-CoV-2 productively infects induced pluripotent stem-cell derived bronchial organoids iALI and persisted over the long term C_LIO_LISARS-CoV-2 iALI infection results in cilia destruction, increased mucus secretion and a strong innate immune response C_LIO_LISARS-CoV-2 infection elicited a higher and earlier innate immune response in iCOPD C_LIO_LISARS-CoV-2 infection in iCOPD respond less to antivirals C_LI Short AbstractSARS-CoV-2 causes severe lower respiratory tract infection in COVID-19 patients, which can persist over time. Here, we used an in-house developed in vitro airway organoid derived from induced human pluripotent stem cells (iALI) to study SARS-CoV-2 infection over long term in healthy or COPD patients whom respiratory failure is at risk during infection. Our results show that SARS-CoV-2 infection results in high and lethal infection of bronchial epithelial cells, that persist over time, inducing mucus secretion, destruction of ciliated cells and specific cytokine release. A late innate immune response is observed in the healthy iALI, while in iCOPD, it appears earlier and stronger, suggesting a different sensing of SARS-CoV-2 in COPD patients, accompanied by a reduce sensitivity to antivirals. In conclusion, our study demonstrates that the iALI organoid model is a powerful tool for investigating bronchial tissue responses to long term respiratory viral infections, from healthy to pathologic patients.

cell biology↗

bioRxiv2024

The multifunction Coxiella effector Vice stimulates macropinocytosis and interferes with the ESCRT machinery

Intracellular bacterial pathogens divert multiple cellular pathways to establish their niche and persist inside their host. Coxiella burnetii, the causative agent of Q fever, secretes bacterial effector proteins via its Type 4 secretion system to generate a Coxiella-containing vacuole (CCV). Manipulation of lipid and protein trafficking by these effectors is essential for bacterial replication and virulence. Here, we have characterized the lipid composition of CCVs and discovered that the effector Vice interacts with phosphoinositides and membranes enriched in phosphatidylserine (PS) and lysobisphosphatidic acid (LBPA). Remarkably, eukaryotic cells ectopically expressing Vice present compartments that resemble early CCVs in both morphology and composition. We discovered that the biogenesis of these compartments relies on the double function of Vice. The effector protein initially localizes at the plasma membrane of eukaryotic cells where it triggers the internalization of large vacuoles by macropinocytosis. Then, Vice stabilizes these compartments by perturbing the ESCRT machinery and inhibiting the formation of intraluminal vesicles (ILVs). Collectively, our results reveal that Vice is an essential C. burnetii effector protein capable of hijacking two major cellular pathways to shape the bacterial replicative niche. Significance statementCoxiella burnetii is a unique bacterial pathogen that secretes more than a hundred effector proteins to manipulate cellular processes and establish a replicative niche, the Coxiella-containing vacuole (CCV). Our study identified host cell lipids that are actively recruited by the bacterium to the CCV. Using a library of effector mutants, we identified the protein Vice (for Vacuole-inducing Coxiella effector) as the first bacterial effector capable of interacting with lysobisphosphatydic acid-enriched membranes and accumulating this lipid to CCVs. We show that Vice is also capable of stimulating macropinocytosis and inhibiting the ESCRT machinery. Together, our data show how a single bacterial effector can manipulate different cellular processes to favor the biogenesis of a bacterial pathogens niche.

microbiology↗

bioRxiv2024

Neutrophils in People Living With HIV-1 on antiretroviral treatment conserve their cytokine and chemokine secretion capacity and display enhanced expression of Fc receptors

Neutrophils are innate immune cells with key immunomodulatory functions. In a murine retroviral model, we previously showed their essential role in promoting protective immunity during antiviral antibody therapy via Fc-Fc{gamma} receptor (Fc{gamma}R) interactions. Here, we investigated the immunomodulatory properties of neutrophils in the context of HIV-1 infection and therapy through a comprehensive analysis of their functional activation and the regulation of Fc{gamma}R expression. Neutrophils from healthy donors (HD) and people living with HIV-1 (PLWH) were stimulated with TLR ligands, free HIV-1, immune complexes (ICs) formed with broadly neutralizing antibodies (bNAbs), or pro-inflammatory cytokines (TNF, IFN{gamma}). In response, they secreted various cytokines and chemokines that can recruit and activate immune cells in a stimulus-dependent manner. Compared to TLR agonist and cytokine activation, HD neutrophils showed limited cytokine production in response to free HIV-1 or ICs alone as well as a minimal Fc{gamma}R modulation. However, PLWH neutrophils showed heightened responsiveness to microbial stimuli linked to HIV-1 pathogenesis, secreting higher levels of IFN{gamma}, CXCL1, CCL2, CCL3, and CCL4. They also expressed higher levels of two activating Fc{gamma}Rs (Fc{gamma}RI and Fc{gamma}RIIIb), as well as CD11b, CD63, CXCR4, and PD-L1, indicating an altered activation state. These findings highlight the influence of the inflammatory milieu on neutrophil function and Fc{gamma}R regulation in HIV-1 infection and mAb-based therapies.

immunology↗

bioRxiv2023

Specific targeting and clustering of Phosphatidylserine lipids by RSV M protein is critical for virus particle production

Human Respiratory Syncytial virus (RSV) is the leading cause of infantile bronchiolitis in the developed world and of childhood deaths in resource-poor settings. The elderly and the immunosuppressed are also affected. It is a major unmet target for vaccines and anti-viral drugs. RSV assembles and buds from the host cell plasma membrane by forming infections viral particles which are mostly filamentous. A key interaction during RSV assembly is the interaction of plasma membrane lipids with the Matrix (M) protein layer forming at assembly sites. Although the structure of RSV M protein dimer is known, it is unclear how the viral M proteins interact with certain plasma membrane lipids to promote viral assembly. Here, we demonstrate that M proteins cluster at the plasma membrane by selectively binding with phosphatidylserine (PS). Our in vitro studies suggest that M binds PS lipid as dimers and M mutant with a phosphomimetic substitution inhibits interaction with PS lipids. The presence of other negatively charged lipids like PI(4, 5)P2 does not affect RSV M ability to bind, while cholesterol negatively affects M interaction with lipids. Moreover, we show that the initial binding of the RSV M protein with lipids is independent of the cytoplasmic tail of fusion (F) glycoprotein (FCT). It is the first in vitro study of M interaction with plasma membrane lipids. M binding to plasma membrane may represent a viable therapeutic strategy for small molecules that will block viral spread.

biochemistry↗

bioRxiv2022

HIV-1 diverts actin debranching mechanismsfor particle assembly and release in CD4 Tlymphocytes.

Enveloped viruses assemble and bud from the host cell membranes. Possible roles of cortical actin in these processes have often been a source of controversy. Here, we assessed the involvement of the Arp2/3 mediated branched actin in HIV-1 assembly at the membrane of infected CD4 T lymphocytes. Our results show that actin debranching not only increases HIV-1 release but also the number of individual HIV-1 assembly clusters present at the cell plasma membrane unravelling new mechanisms. Indeed, we showed that, in infected T lymphocytes, HIV-1 Gag prefers areas deficient in F-actin for assembly. In vitro, we could reproduce and quantify this mechanism using model systems. Finally, we found that the actin debranching factor, Arpin, an Arp2/3 inhibitor, is recruited by Gag at the cell membrane to promote virus assembly. Altogether, our data show that HIV-1 favors local actin debranching for assembly and release by subverting the host factor Arpin.

microbiology↗

bioRxiv2022

Quantification of membrane binding and diffusion using Fluorescence Correlation Spectroscopy diffusion laws

Many transient processes in cells arise from the binding of cytosolic proteins to membranes. Quantifying this membrane binding and its associated diffusion in the living cell is therefore of primary importance. Dynamic photonic microscopies, e.g. single/multiple particle tracking, fluorescence recovery after photobleaching and fluorescence correlation spectroscopy (FCS) enable noninvasive measurement of molecular mobility in living cells and their plasma membranes. However, FCS with a single beam waist is of limited applicability with complex, non Brownian, motions. Recently, the development of FCS diffusion laws methods has given access to the characterization of these complex motions, although none of them is applicable to the membrane binding case at the moment. In this study, we combined computer simulations and FCS experiments to propose an FCS diffusion law for membrane binding. First, we generated computer simulations of spot-variation FCS (svFCS) measurements for a membrane binding process combined to 2D and 3D diffusion at the membrane and in the bulk/cytosol, respectively. Then, using these simulations as a learning set, we derived an empirical diffusion law with three free parameters: the apparent binding constant KDapp, the diffusion coefficient on the membrane D2D and the diffusion coefficient in the bulk/cytosol, D3D. Finally, we monitored, using svFCS, the dynamics of retroviral Gag proteins and associated mutants during their binding to supported lipid bilayers of different lipid composition or at plasma membranes of living cells and we quantified KDapp and D2D in these conditions using our empirical diffusion law. Based on these experiments and numerical simulations, we conclude that this new approach enables correct estimation of membrane partitioning and membrane diffusion properties (KDapp and D2D) for peripheral membrane molecules.

biophysics↗

bioRxiv2021

Full assembly of HIV-1 particles requires assistance of the membrane curvature factor IRSp53.

During HIV-1 particle formation, the requisite plasma membrane curvature is thought to be solely driven by the retroviral Gag protein. Here, we reveal that the cellular I-BAR protein IRSp53 is required for the progression of HIV-1 membrane curvature to complete particle assembly. Partial gene editing of IRSp53 induces a decrease in viral particle production and a viral bud arrest at half completion. Single molecule localization microscopy at the cell plasma membrane shows a preferential localization of IRSp53 around HIV-1 Gag assembly sites. In addition, we observe the presence of IRSp53 in purified HIV-1 particles. Finally, HIV-1 Gag protein localizes preferentially to IRSp53 I-BAR domain induced curved membranes on giant unilamellar vesicles. Overall, our data reveal a strong interplay between IRSp53 I-BAR and Gag at membranes during virus assembly. This highlights IRSp53 as a crucial host factor in HIV-1 membrane curvature and its requirement for full HIV-1 particle assembly.

biophysics↗