La moule méditerranéenne comme modèle innovant pour l'étude du développement et du fonctionnement du système nerveux larvaire // The Mediterranean mussel as an innovative model for studying development and function of a larval nervous system

Developmental neurobiology, aimed at understanding how neurons and neuronal circuits develop, interact, and function, is an essential pillar of neuroscience. Studying the early development of the nervous system, a particularly sensitive time window, opens the way to preventive approaches for the early detection of neural malformations. The choice of laboratory model organisms, while of crucial importance, is still facing major limitations, whether experimental, ethical, linked to species-specific traits or the phylogenetic distance between organisms. The diversification and multiplication of organisms used as study models is one of the keys to overcoming these limitations. The Mediterranean mussel Mytilus galloprovincialis is a marine mollusk that is widely used in ecotoxicological, immunological, and stress-response studies (1-5). M. galloprovincialis adults have thus, for example, been used to study the physiological effects of pollutants, such as heavy metals, pesticides, and endocrine disruptors (2,6,7). However, thanks, at least in part, to work of the host laboratory and collaborators, M. galloprovincialis can now also be regarded as an emerging model system in developmental and cell biology (8). This is of particular importance, because patterning and development of the embryo and the early larva are particularly vulnerable to external disruption, for example by anthropogenic pollutants (9). Furthermore, the whole mollusk phylum suffers from a chronic lack of powerful model systems allowing in-depth molecular characterizations of biological processes, including mechanistic explorations of embryonic and larval development (10). The existing studies on mollusk nervous system development hence chiefly consist of anatomical descriptions based on neurotransmitter immunohistochemistry (11-15). Similarly, for developing mussels, while there are some studies focusing on effects of neurotoxicants, they are generally limited to reporting anatomical alterations of the developing nervous system (15-17). To address some of the current knowledge gaps, the present project proposes to functionally characterize the developing nervous system of the Mediterranean mussel M. galloprovincialis. By leveraging previous work by the host laboratory on anatomical and molecular aspects of its neurodevelopment, the aim is to link anatomical and molecular features of the developing M. galloprovincialis nervous system to specific larval behaviors. To this end, the host laboratory has already created several resources, including a developmental bulk transcriptome including 15 timepoints from fertilization to the late larval stages and single nucleus transcriptome atlases of two key larval stages. In addition, several experimental protocols have been established for M. galloprovincialis embryos and larvae, including those for pharmacological treatments, live imaging, in situ hybridization chain reaction, immunofluorescence, and quantitative PCR. The proposed work will make use of these resources and protocols to define larval behaviors, assess their neural control mechanisms as well as the molecular mechanisms controlling their development. Comparisons of the results obtained in M. galloprovincialis with datasets from other species will allow novel insights into the evolution of the developmental processes underlying the neural control of larval behavior. While potentially revealing paradigms valid for the development of all nervous systems, including that of humans, this work has particular importance for our understanding of the possibly disruptive effects of anthropogenic pollutants (such as neurological drugs) on larval ecology.
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Developmental neurobiology, aimed at understanding how neurons and neuronal circuits develop, interact, and function, is an essential pillar of neuroscience. Studying the early development of the nervous system, a particularly sensitive time window, opens the way to preventive approaches for the early detection of neural malformations. The choice of laboratory model organisms, while of crucial importance, is still facing major limitations, whether experimental, ethical, linked to species-specific traits or the phylogenetic distance between organisms. The diversification and multiplication of organisms used as study models is one of the keys to overcoming these limitations. The Mediterranean mussel Mytilus galloprovincialis is a marine mollusk that is widely used in ecotoxicological, immunological, and stress-response studies (1-5). M. galloprovincialis adults have thus, for example, been used to study the physiological effects of pollutants, such as heavy metals, pesticides, and endocrine disruptors (2,6,7). However, thanks, at least in part, to work of the host laboratory and collaborators, M. galloprovincialis can now also be regarded as an emerging model system in developmental and cell biology (8). This is of particular importance, because patterning and development of the embryo and the early larva are particularly vulnerable to external disruption, for example by anthropogenic pollutants (9). Furthermore, the whole mollusk phylum suffers from a chronic lack of powerful model systems allowing in-depth molecular characterizations of biological processes, including mechanistic explorations of embryonic and larval development (10). The existing studies on mollusk nervous system development hence chiefly consist of anatomical descriptions based on neurotransmitter immunohistochemistry (11-15). Similarly, for developing mussels, while there are some studies focusing on effects of neurotoxicants, they are generally limited to reporting anatomical alterations of the developing nervous system (15-17). To address some of the current knowledge gaps, the present project proposes to functionally characterize the developing nervous system of the Mediterranean mussel M. galloprovincialis. By leveraging previous work by the host laboratory on anatomical and molecular aspects of its neurodevelopment, the aim is to link anatomical and molecular features of the developing M. galloprovincialis nervous system to specific larval behaviors. To this end, the host laboratory has already created several resources, including a developmental bulk transcriptome including 15 timepoints from fertilization to the late larval stages and single nucleus transcriptome atlases of two key larval stages. In addition, several experimental protocols have been established for M. galloprovincialis embryos and larvae, including those for pharmacological treatments, live imaging, in situ hybridization chain reaction, immunofluorescence, and quantitative PCR. The proposed work will make use of these resources and protocols to define larval behaviors, assess their neural control mechanisms as well as the molecular mechanisms controlling their development. Comparisons of the results obtained in M. galloprovincialis with datasets from other species will allow novel insights into the evolution of the developmental processes underlying the neural control of larval behavior. While potentially revealing paradigms valid for the development of all nervous systems, including that of humans, this work has particular importance for our understanding of the possibly disruptive effects of anthropogenic pollutants (such as neurological drugs) on larval ecology.
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Début de la thèse : 01/10/2026

Public funding alone (i.e. government, region, European, international organization research grant)

Concours pour un contrat doctoral

Sorbonne Université SIS (Sciences, Ingénierie, Santé)

515 Complexité du vivant

A background and previous experience in developmental and molecular biology are desirable. A fundamental interest in comparative biology and for work on alternative model systems is required. A strong motivation for experimental work and live imaging analyses is a must. Notions in bioinformatics are a plus.
A background and previous experience in developmental and molecular biology are desirable. A fundamental interest in comparative biology and for work on alternative model systems is required. A strong motivation for experimental work and live imaging analyses is a must. Notions in bioinformatics are a plus.