Biology subjects

Alifano, M.

Publications and source records attributed to Alifano, M..

5 recordsLinked to original sources

bioRxiv2024

Radiotherapy triggers pro-angiogenic signaling in human lung

Radiotherapy is one of the main therapeutic options for the treatment of lung cancer. Although highly efficient, radiation cause severe damages to normal tissue and radio-induced toxicities vary from mild pneumonitis to pulmonary fibrosis. The mechanism leading to these toxicities remain unclear. To investigate the molecular responses of human lung to radiotherapy, we analyzed, by single cell RNAseq, lung tissue resected in the vicinity of the tumor (i.e. treated with radiation) and compared the transcriptional profiles of the distinct lung populations from the same patient removed at distance from the tumor (i.e. non-treated with radiation). Analysis of six lung samples from patients suffering from Pancoast tumor, a rare lung malignancy that requires neo-adjuvant radiotherapy before surgery, revealed a strong induction of VEGF signaling after radiotherapy. Expression of VEGFA, one of the canonical pro-angiogenic ligands, was found upregulated in multiple cell populations in lung exposed to high doses of radiation. Irradiated capillaries, particularly gCap cells, expressing KDR/VEGFR2, present transcriptional profile similar to tip cells, characterized by sprouting and motility capacities. In addition, we identified a sub-population of alveolar macrophages expressing FLT1/VEGFR1, a receptor for VEGFA, in lung tissues treated by radiotherapy. Cell-Cell communication analysis revealed that FLT1/VEGFR1 positive macrophages interact with tip cells after radiotherapy through IL1B-IL1R signaling. Lastly, analysis of mouse single cell dataset confirmed the increase in the proportion of gCap cells presenting a tip-like phenotype after radiation injury. Altogether, this study describes, at the single cell level, the pro-angiogenic responses of human lung after radiotherapy. These results will lead to a better understanding of the physiopathology of lung radiation injury and may pave the way to optimize treatments to improve patients quality of life.

cancer biology↗

bioRxiv2024

Mitochondrial metabolism sustains CD8+ T cellmigration for an efficient infiltration into solid tumors

The ability of CD8+ T cells to infiltrate solid tumors and reach cancer cells is associated with improved patient survival and responses to immunotherapy. Thus, identifying the factors controlling T cell migration in tumors is critical, so that strategies to intervene on these targets can be developed. Although interstitial motility is a highly energy-demanding process, the metabolic requirements of CD8+ T cells migrating in a 3D environment remain unclear. Here, we demonstrate that the tricarboxylic acid (TCA) cycle is the main metabolic pathway sustaining human CD8+ T cell motility in 3D collagen gels and tumor slices while glycolysis plays a much minor role. Using pharmacological and genetic approaches, we report that CD8+ T cell migration depends on the mitochondrial oxidation of glucose and glutamine, but not fatty acids, and both ATP and ROS produced by mitochondria are required for T cells to migrate. Pharmacological interventions to increase mitochondrial activity improve CD8+ T cells intra-tumoral migration and CAR T cell recruitment into tumor islets leading to better control of tumor growth in human xenograft models. Our study highlights the rationale of targeting mitochondrial metabolism to enhance the migration and antitumor efficacy of CAR T cells in treating solid tumors.

immunology↗

bioRxiv2021

The lethal triad: SARS-CoV-2 Spike, ACE2 and TMPRSS2. Mutations in host and pathogen may affect the course of pandemic.

Variants of SARS-CoV-2 have been identified rapidly after the beginning of pandemic. One of them, involving the spike protein and called D614G, represents a substantial percentage of currently isolated strains. While research on this variant was ongoing worldwide, on December 20th 2020 the European Centre for Disease Prevention and Control reported a Threat Assessment Brief describing the emergence of a new variant of SARS-CoV-2, named B.1.1.7, harboring multiple mutations mostly affecting the Spike protein. This viral variant has been recently associated with a rapid increase in COVID-19 cases in South East England, with alarming implications for future virus transmission rates. Specifically, of the nine amino acid replacements that characterize the Spike in the emerging variant, four are found in the region between the Fusion Peptide and the RBD domain (namely the already known D614G, together with A570D, P681H, T716I), and one, N501Y, is found in the Spike Receptor Binding Domain - Receptor Binding Motif (RBD-RBM). In this study, by using in silico biology, we provide evidence that these amino acid replacements have dramatic effects on the interactions between SARS-CoV-2 Spike and the host ACE2 receptor or TMPRSS2, the protease that induces the fusogenic activity of Spike. Mostly, we show that these effects are strongly dependent on ACE2 and TMPRSS2 polymorphism, suggesting that dynamics of pandemics are strongly influenced not only by virus variation but also by host genetic background.

microbiology↗

bioRxiv2020

CAR T cell entry into tumor islets is a two-step process dependent on IFNγ and ICAM-1

Adoptive transfer of T cells expressing chimeric antigen receptors (CARs) has shown remarkable clinical efficacy against advanced B cell malignancies but not yet against solid tumors. Here, we used fluorescent imaging microscopy and ex vivo assays to compare the early functional responses (migration, Ca2+ and cytotoxicity) of CD20 and EGFR CAR T cells upon contact with malignant B and carcinoma cells. Our results indicate that CD20 CAR T cells rapidly form productive ICAM-1-dependent conjugates with their targets. By comparison, EGFR CAR T cells only interact at first with a subset of carcinoma cells located at the periphery of tumor islets. After this initial peripheral activation, EGFR CAR T cells progressively infiltrate the center of tumor cell regions. The analysis of this two-step entry process shows that activated CAR T cells trigger the upregulation of ICAM-1 on tumor cells in an IFN{gamma}-dependent pathway. The blockade of ICAM-1/LFA-1 interactions prevents CAR T cell recruitment into tumor islets. The requirement for IFN{gamma} and ICAM-1 to enable CAR T cell entry into tumor islets is of significance for improving CAR T strategy in solid tumors.

immunology↗

bioRxiv2020

ACE2 polymorphisms and individual susceptibility to SARS-CoV-2 infection: insights from an in silico study

The current SARS covid-19 epidemic spread appears to be influenced by ethnical, geographical and sex-related factors that may involve genetic susceptibility to diseases. Similar to SARS-CoV, SARS-CoV-2 exploits angiotensin-converting enzyme 2 (ACE2) as a receptor to invade cells, notably type II alveolar epithelial cells. Importantly, ACE2 gene is highly polymorphic. Here we have used in silico tools to analyze the possible impact of ACE2 single-nucleotide polymorphisms (SNPs) on the interaction with SARS-CoV-2 spike glycoprotein. We found that S19P (common in African people) and K26R (common in European people) were, among the most diffused SNPs worldwide, the only two SNPs that were able to potentially affect the interaction of ACE2 with SARS-CoV-2 spike. FireDock simulations demonstrated that while S19P may decrease, K26R might increase the ACE2 affinity for SARS-CoV-2 Spike. This finding suggests that the S19P may genetically protect, and K26R may predispose to more severe SARS-CoV-2 disease.

microbiology↗