Muscular dystrophies, such as Duchenne muscular dystrophy (DMD), are characterized by dysfunction of myofibers and increase in the collagenous endomysial tissue, known as fibrosis. Because the primary defect targets myofibers and myogenic cells, previous work has been almost exclusively focused on muscle stem cells (MuSCs). Moreover, fibrosis has been regarded as a compensatory response to muscle damaging. However, more recent studies have shown that increased fibrosis is predictive of higher muscle damage and earlier muscle function loss in DMD patients. In regenerating skeletal muscle, myogenesis is operated by MuSCs and is sustained by tightly coordinated environmental neighborhood, including inflammatory cells, vascular cells and fibro-adipogenic progenitors (FAPs). FAPs are mesenchymal fibroblastic cells located in the interstitial space between the muscle fibers. During muscle regeneration, FAP homeostasis is tightly regulated by pro-inflammatory and anti-inflammatory macrophages. Once the muscle is repaired, FAPs return to quiescence. Instead, in pathological contexts, as in DMD, FAPs proliferate and differentiate leading to increased fibrosis and fat infiltrations. Although FAPs are the main cells responsible for fibrosis in degenerative myopathies, the molecular pathways regulating their fate and functions are not known. Despite the importance of this process, the mechanisms by which fibrogenesis takes place and is molecularly controlled have been overlooked. This lack of knowledge may be due both to the complexity exhibited by the immune system in a chronic situation and to the lack of markers to properly identify and characterize both immune and fibroblastic cells. Thanks to the recent data generated by the teams of the Consortium, specific cell populations (fibroblastic and immune cells) have been identified in the dystrophic context, allowing to investigate their function in fibrogenesis. Moreover, they identified several signaling pathways that are activated in FAPs, notably in a myopathic context, and their control by inflammatory cells, which constitutes a new and major focus in the study of degenerative myopathies. Interestingly, pharmacological targeting of some of these pathways was shown to decrease fibrosis in DMD mice, highlighting the relevance of FAP signaling pathways in fibrosis establishment in degenerative myopathies. Overall the consortium data allow proposing the following hypothesis: in dystrophic muscle, new crosstalks are established between activated MuSCs, macrophages and FAPs that involve paracrine and cell-to-cell signaling pathways to promote fibrosis. The Myo-Fibrosis project proposes to unravel the complexity of the distinct cell subpopulations involved in fibrosis (using unbiased single cell approaches) and the signaling pathways controlling fibrosis (using a series of genetically modified cells in vivo and ex vivo). The elucidation of an integrated and comprehensive framework of the cellular events underlying the steps of muscle fibrosis represents crucial missing information, which will undoubtedly push forward the frontier of our current knowledge on fibrogenesis. Because fibrosis is the major obstacle for cell and gene therapy approaches that are proposed, understanding the mechanisms controlling fibrosis is of paramount importance to open promising therapeutic avenues for muscular dystrophies.

The overall goal of this proposal is to understand how cilia and flagella are assembled and how cilia diversity is generated. These highly organized organelles play fundamental biological functions in a wide range of organisms. For example, motile cilia and flagella are required for fluid flow and cell motility in various tissues. Cilia are also involved in cell signaling during development. As a result, in humans, cilia dysfunction leads to a wide range of pathologies, called ciliopathies. The first critical step required for cilia or flagella assembly is the conversion of the centriole into the basal body. This step involves the docking of the centriole to cytoplasmic vesicles and the formation of the Transition Zone (TZ), a complex structure of the ciliary base. The TZ plays an essential role by bridging the basal body to the plasma membrane and gating proteins in and out of the cilium. Numerous components of the TZ have been identified, among which many are mutated in human ciliopathies. However, the TZ shows structural and molecular variations between cell types and species, which still need to be understood. As well, many unsolved questions remain regarding the molecular mechanisms supporting the existence of different types of cilia and different modes of assembly between organisms or cell types. In humans, cilia diversity is emphasized by comparing the architecture of the highly organized flagellum of sperm cells to that of primary cilium found on many cell types during development. Specific features are associated with mammalian sperm flagella, such as the annulus, but the mechanisms that control the assembly of the mammalian sperm flagella and its specific attributes are largely unknown. Ancient observations proposed that the assembly of sperm flagella in Drosophila and humans involves analogous elements, the ring centriole and the annulus respectively, which are found to be required for flagella formation or integrity during spermiogenesis. The composition of the ring centriole and of the annulus is poorly understood, but recent work demonstrates that proteins required to build the TZ of cilia in all organisms are involved in their formation. Therefore, our working hypothesis is that the ring centriole and the annulus are evolutionary derived TZ structures and our objectives are to determine how these structures are built and related to the ciliary TZ and how variations in TZ composition may account for cilia diversity. In this context, our project aims at: 1) Characterizing proteins required for TZ and/or ring centriole assembly in mouse and Drosophila, by identifying the proteins associated with these compartments using the innovative APEX proximity-dependent labelling strategy; 2) Establishing the first thorough description of the proteome of mammalian sperm annulus; 3) Identifying novel genes required for TZ assembly by a genetic screen in Drosophila; 4) Investigating the implication of the above identified proteins in the process of cilia and flagella assembly in Drosophila and mouse. This project relies on original preliminary observations and bridges two teams with perfect complementary expertise in cilia and male reproductive biology and two distant model organisms, Drosophila and mouse. It focuses on a key feature involved in cilia formation: the Transition Zone (TZ), and explores a new avenue which questions how the TZ has evolved and may contribute to the assembly of the sperm flagella. Altogether, this project will unravel novel components required to build the TZ and bring novel insights into the mechanisms that contribute to generate cilia diversity in animals. Last, it will have important spin-offs in medical research by bringing new understandings of human ciliopathies, in particular of male infertility.

The world is currently facing a pandemic of a new emerging virus from the coronavirus family named COVID-19. Detection of infected patients is crucial to break the epidemic situation. As a consequence it is essential to diagnose fast and in large number populations to sort rapidly those who are infected. Diagnosis of COVID-19 is carried out by a molecular biology approach consisting in the detection of the COVID-19 RNA genome by a quantitative RT-PCR approach. This strategy is efficient but is time consuming and needs a trained medical staff in a dedicated laboratory. Here we propose a new strategy based on physics technologies :acoustic and optical. AcOstoVIe project aims to prototype a label-free COVID-19 diagnosis device, based by on 2 biosensors on a same quartz substrate. A Quartz Crystal Microbalance (QCM) and an optical reflexion – existing technologies already tested for ebola virus diagnosis – will be integrated in a sytem to detect COVID-19 (i) RNA genome (ii) viral particles and (iii) serology of infected patients. Compared to existing technologies, AcOstoVIe project will provide the valuable advantages : (i) point-of-care diagnosis, (ii) faster (< 30 min), (iii) friendly user (no trained medical staff), (iv) nomad without restriction of dedicated laboratory localization, (v) double check detection, (vi) partly reusable. From the Proof of Concept delivered after T0+12, the system will be next challenged with infectious and non-infectious sample fluids issued from collaborations with medical infrastructures and virology laboratories. The final compact system will be next co-design with practitioners.

The goal of the GELIHPARBAL project is to create injectable hydrogels that can be used as an emergency solution for deep and jagged wounds, to decrease bleeding immediate threat while improving muscle repair and functional skin healing. A new avenue of research, based on the development of biomaterials, has appeared in recent years as an alternative to classical tissue reconstruction approaches, such as grafts. Their aim is to provide a scaffold that will activate or guide cellular responses to enhance or trigger tissue regeneration. Nevertheless, if these biomaterials are trying to reproduce specific properties of the extracellular matrix (notably rigidity) to influence cell fate, elasticity has seldom been considered so far. Concomitantly, the possibility to provide haemostatic competences to these biomaterials, through induction of the blood clotting cascade by prothrombotic molecules and through filling and compression of the wound, opens new possibilities to control haemorrhagic risks. The GELIHPARBAL project therefore aims to develop an innovative therapeutic approach for deep wounds based on the use of injectable porous elasto-mimetic hydrogels that, through their intrinsic properties, allow concomitantly (1) the haemostatic filling of deep wounds, while (2) providing a specific guidance of muscle and skin repair. A major innovation will be the injectable formulation of porous elastic hydrogels that can compressively fill and conform accurately to the wound shape; and allow wound healing cells colonization while reinforcing their regenerative properties through mechanic and structural properties. The elasto-mimetic porous hydrogels developed during a previous ANR project (DHERMIC, ANR-11-TECS-016) will serve as technological basis for the development of the injectable formulations. The coordinating laboratory (Laboratory of tissue biology and therapeutic engineering, LBTI) has indeed reached the "biological" proof of concept of these approaches by validating the efficacy of the hydrogels in forming reconstructed skin equivalents and enhancing skin wound healing in vivo. This project therefore falls within the design and creation of innovative, bioinspired biodegradable and bioactive materials. To reach this ambitious goal, the consortium formed by three institutional partners (CNRS and INSERM) possesses the required competences and expertise’s to develop the biomaterials (LBTI), to finely analyse their mechanical, rheological (RMeS) and biological properties (INMG), and to study and evaluate the improvement of tissue healing and the resulting functionality gain (LBTI) The scientific program is divided in 3 scientific work packages (chemistry/biomaterials, mechanobiology and in vivo) and an administrative WP. They have for goal to 1) design elasto-mimetic haemostatic injectable porous hydrogels of large mechanical versatility; 2) Determine the mechanical and structural properties of porous matrices most effective in guiding proliferation and differentiation of muscle stem cells and in inducing muscle regeneration; 3) develop injectable porous hydrogels that can simultaneously promote muscle and skin regeneration. The administrative task is dedicated to the project and intellectual property management.