Biology subjects

Vodret, S.

Publications and source records attributed to Vodret, S..

3 recordsLinked to original sources

bioRxiv2024

DCs targeted therapy expands CD8 T cell responses to bona-fide neoantigens in lung tumors

Cross-presentation by type 1 cDCs (cDC1) is critical to induce and sustain antitumoral CD8 T cell responses to model antigens, in various tumor settings. However, the impact of cross-presenting cDC1 and the potential of DC-based therapies in tumors carrying varied levels of bona-fide neoantigens (neoAgs) remains unclear. Here we generated a non-small cell lung cancer model with distinct ranges of TMB and MHC-I neoepitopes to test immunogenicity and response to Flt3L+CD40 (DC-therapy). We found that cDC1 are required to broaden the pattern of CD8 responses to basal and acquired neoAgs and DC-therapy strongly inhibits the growth of TMBhigh tumors. In contrast, TMBlow tumors induce weaker responses that are not sufficient to block progression. scRNA transcriptional analysis, immune profiling and functional assays show that DC-therapy triggers the accumulation of lung cDC1 with increased immunostimulatory properties and CD8 T cells with enhanced cytotoxic functions and reduced exhaustion, most prominently in neoAgshigh tumors. We conclude that boosting cDC1 activity is critical to broaden the diversity of anti-tumoral CD8 T cell responses and to leverage neoAgs content for therapeutic advantage.

immunology↗

bioRxiv2023

ALCAM-mediated synapses between DC1 and CD8 T cells are inhibited in advanced lung tumors

Conventional type 1 dendritic cells (DC1) control anti-tumoral CD8 T responses, in lymph nodes and tumor tissues. T-cell activation depends on the establishment of a tight physical interaction with antigen-presenting cell, the immunological synapse (IS). The molecular determinants of DC1-CD8 IS in tumor tissues and how they are regulated during cancer progression remain poorly investigated. Using a reporter for DC1 in a genetic model of non-small cell lung cancer (KP-XCR1venus) we show that IS in lung tissues are abundant and productive at early stages of tumor development but progressively diminish in advanced tumors. Transcriptional profiling and flow cytometry of lung resident DC1 identified a module of adhesion molecules downregulated in advanced tumors. We focused on ALCAM and LFA-1, ligands for CD6 and ICAM-1 on T cells, to investigate their role and functional impact. By immobilizing single receptor agonists on artificial cell surfaces, we demonstrate that ALCAM and LFA-1 are sufficient to trigger cytoskeletal remodeling in early tumor DC1, whereas late tumors DC1 are not responsive. Blocking ALCAM-CD6 interactions in functional assays impairs the acquisition of effector functions in CD8 T cells. Together these data highlight that adhesion molecules required to establish IS in early, immune-reactive, tumors are targeted during tumor progression blunting cross-talk within the IS.

immunology↗

bioRxiv2021

SARS-CoV-2 Spike protein activates TMEM16F-mediated platelet pro-coagulant activity

BackgroundThrombosis of the lung micro-vasculature is a characteristic of COVID-19 disease, which is observed in large excess compared to other forms of acute respiratory distress syndrome and thus suggests a trigger for thrombosis endogenous to the lung. Our recent work has shown that the SARS-CoV-2 Spike protein activates the cellular TMEM16F chloride channel and scramblase. Through a screening on >3,000 FDA/EMA approved drugs, we identified Niclosamide and Clofazimine as the most effective molecules at inhibiting this activity. As TMEM16F plays an important role in the stimulation of the pro-coagulant activity of platelets, and considering that platelet abnormalities are common in COVID-19 patients, we investigated whether Spike directly affects platelet activation and pro-thrombotic function and tested the effect of Niclosamide and Clofazimine on these processes. MethodsWe produced SARS-CoV-2 Spike or VSV-G protein-pseudotyped virions, or generated cells expressing Spike on their plasma membrane, and tested their effects on platelet adhesion (fluorescence), aggregation (absorbance), exposure of phosphatidylserine (flow cytometry for annexin V binding), calcium flux (flow cytometry for fluo-4 AM), and clot formation and retraction. These experiments were also conducted in the presence of the TMEM16F activity inhibitors Niclosamide and Clofazimine. ResultsHere we show that exposure to SARS-CoV-2 Spike promotes platelet activation, adhesion and spreading, both when present on the envelope of virions or upon expression on the plasma membrane of cells. Spike was effective both as a sole agonist or by enhancing the effect of known platelet activators, such as collagen and collagen-related peptide. In particular, Spike exerted a noticeable effect on the procoagulant phenotype of platelets, by enhancing calcium flux, phosphatidylserine externalisation, and thrombin generation. Eventually, this resulted in a striking increase in thrombin-induced clot formation and retraction. Both Niclosamide and Clofazimine almost abolished this Spike-induced pro-coagulant response. ConclusionsTogether, these findings provide a pathogenic mechanism to explain thrombosis associated to COVID-19 lung disease, by which Spike present in SARS-CoV-2 virions or exposed on the surface of infected cells, leads to local platelet stimulation and subsequent activation of the coagulation cascade. As platelet TMEM16F is central in this process, these findings reinforce the rationale of repurposing drugs targeting this protein, such as Niclosamide, for COVID-19 therapy.

pathology↗