Malaria remains a major cause of death and morbidity worldwide affecting 200 million people annually. Plasmodium falciparum (P. falciparum) is responsible for the majority of the 500,000 deaths attributed each year to malaria, but P. vivax, although less virulent, contributes significantly to malaria morbidity. The infection in humans is initiated by the bite of an infected mosquito which inoculates the parasite into the skin. The parasite then migrates to the liver where it interacts with non parenchymal cells (NPC) before invading the hepatocytes within which it replicates. Once mature, the parasite passes into the blood initiating the erythrocytic stage of its development which is associated with the disease symptoms and transmission. Targeting the parasite before of during its development within the liver is thus an ideal target for prophylactic approaches. But the search for novel or improved means to eliminate malaria necessitates appropriate experimental models. So far, most if not all of our basic knowledge on the parasite-host interactions during the liver stage comes from murine models of experimental malaria. Although these models have non questionable advantages, they do not recapitulate the biology of the human host cells and of the human malaria parasites. There is thus a critical need for developing novel and innovative tools, biologically more relevant to humans for the identification of novel therapeutic targets. Additionally, in vitro studies on P. falciparum or P. vivax liver stages, including screening for new antimalarial compounds, are so far routinely performed using 2D cultures of human hepatocytes within which the parasite development is not efficient and is incomplete. Moreover, these 2D systems recapitulates only partially the physiology of the host cell and do not reproduce the complex 3D architecture of the liver. Yet, it is clearly established that heterotypic cell interactions and 3D systems improve human hepatocyte functions and the predictivity of drug metabolism and toxicity assays. Finally, these 2D monocellular systems preclude any study of the interactions between the parasite and liver NPC which are, so far, largely unknown for human malaria parasites. In this context, and based on the partners extensive knowledge of human Plasmodium liver stage and human hepatic cells isolation and culture, we propose to develop new 3D organoid culture systems, including multicellular systems composed of human hepatocytes and NPC, in order to improve in vitro liver stage development, to assess the cross-talk between the parasite and the NPC and evaluate efficacy of chemotherapeutic and immunoprophylatic interventions targeting Plasmodium liver stages. Finally, implementation of this project will provide marketable systems for applied research in malaria but also in other hepatotropic pathogens.

Azole resistance in Aspergillus is one of the emerging public health concerns, listed as a WHO priority and suited to an integrated One Health approach. Selective pressure due to the use of azole pesticides in agriculture being incriminated, identification of clinical and environmental resistance patterns, and a greater understanding of the factors driving this resistance are urgently needed in order to issue recommendations to the stakeholders. The multidisciplinary AspergillusOne-health project strengthened with model and innovative methodologies (WGS, genotyping, MALDI typing, metabarcoding, AI) aims to identify hotspots as possible sources for selection of azole-resistance in the environment, after the detection of azole-resistant Aspergillus in patients and patiens's home, avian facilities, the environment (farming and sawmills), and detection of the azole fungicides in soil and air. The role of resistance trait on Aspergillus fitness cost will be investigated, using environmental strains and mutants selected after fungicide pressure, to assess its clinical involvement.

Obesity is associated with increased severity of infectious diseases. There is an urgent need to provide adapted lifestyle recommendation to reduce that risk which could be due to low grade inflammation and increased immune checkpoint (ICP) overexpression such as the PD-1/PDL1 pathway that leads to exhaustion of T-cells. Nutrim_Check is a new translational research collaborative network involving 4 groups of investigators that is organized into 6 complementary work-packages. Combining expertise in nutrition, metabolism, immunology and large-scale data analysis, our aim is to assess the interaction between NUTRition, IMmune CHECKpoints, and immune and metabolic health. Thanks to access to databases and biobanks with blood and adipose tissue samples from existing cohorts of subjects with metabolic deterioration, we will characterize obesity-related and cell and tissue-specific T cell dysfunction (ICP expression) and explore the interaction between dietary patterns, nutrients, gut microbiota (GM), metabolites and ICP modification (WP1). We will evaluate if T cell dysfunction can be rescued after dietary intervention known to improve metabolism and inflammation in a pilot study (WP2, i.e. called the pro immune diet). Mechanistic insights linking changes of T cell ICP expression will be addressed using ex vivo and in vitro models from human cells and detailed immune cell characterization will be undertaken (WP3). The infectious model of investigation will be the COVID-19, but this project extends broadly to viral infection vulnerability. Of note, an holistic and standardized mass cytometry approach will be used to obtain a detailed phenotyping of the immune populations. Patients from the pilot nutritional intervention will also be phenotyped in depth at the molecular level (metagenomics and metabolomics, WP4) and large-scale data analysis will be undertaken thanks to local expertise in biostatistic and machine learning (WP5). We will explore a novel not yet explored idea that chronic inflammatory tone due to increased expression of ICP contributes to adaptive immune evasion and sustained viral infection in dietary-related diseases. We propose this phenomenon may be fixable by nutritional amelioration in vulnerable populations such as people with obesity and metabolic diseases. Thanks to precise coordination (WP6), the project will provide information of academic and industrial interest with new information on food compounds known to broaden their spectrum of consumption, with emphasis on the immune response. The communication and dissemination Strategy will address the various target groups including the public, food, pharma and healthcare sectors and policy makers

Cellular metabolism is becoming an emerging field of investigation in immunology. For instance, it has been recently shown that a switch from oxidative phosphorylation to aerobic glycolysis in conventional T cells is a prerequisite for their proper activation. CD4+Foxp3+ regulatory T cells (Tregs) play a major role in the control of autoimmune and chronic inflammatory diseases. Current knowledge concerning the cellular metabolic characteristics of Tregs is limited and published studies are controversial. In this project, we will study the role of glucose and lipid metabolism in Treg homeostasis and function. First, we will compare the metabolic features of resting versus effector Tregs, and of Tregs from lymphoid versus non-lymphoid tissues. We will also analyze the effect of different types of chronic inflammation (such as high fat diet, cancer, autoimmunity or chronic infection) on Treg metabolism in specific tissues. Together, these data will allow us to obtain an integrative view of the metabolic features of Treg subsets according to their origin, activation state, tissue localization and inflammatory environment. We hypothesize that Tregs modify their metabolism depending on external cues and environment, providing an explanation for the existing controversies in the literature. Furthermore, we will use novel and unique models of conditional knock-out mice for genes that control critical hubs of glucose and lipid metabolism, to better understand how different aspects of glucose and lipid metabolism specifically in Tregs affect their biology in different tissues and thus their capacity to control inflammation. We will evaluate the influence of critical metabolic checkpoints for the development of spontaneous autoimmunity and other chronic inflammatory processes. Finally, in the last part of the project, we will make use of our conditional knock-out mice to narrow down the mechanism of action of metformin, a drug widely used in type 2 diabetic patients to regulate cellular metabolism. Because the drug has also an immuno-regulatory effect, we will assess whether part of its therapeutic action is due to a direct effect on Tregs. All in all, this project will increase our basic knowledge on the metabolism of Tregs, its impact on Treg homeostasis and function depending on environmental cues and last but not least, improve our understanding of the pathophysiology of major chronic immune-mediated diseases that are controlled by Tregs.