Plateforme d’imagerie


Année de publication : 2018

Anna M Lilja, Veronica Rodilla, Mathilde Huyghe, Edouard Hannezo, Camille Landragin, Olivier Renaud, Olivier Leroy, Steffen Rulands, Benjamin D Simons, Silvia Fre (2018 May 23)

Clonal analysis of Notch1-expressing cells reveals the existence of unipotent stem cells that retain long-term plasticity in the embryonic mammary gland.

Nature cell biology : DOI : 10.1038/s41556-018-0108-1 En savoir plus

Recent lineage tracing studies have revealed that mammary gland homeostasis relies on unipotent stem cells. However, whether and when lineage restriction occurs during embryonic mammary development, and which signals orchestrate cell fate specification, remain unknown. Using a combination of in vivo clonal analysis with whole mount immunofluorescence and mathematical modelling of clonal dynamics, we found that embryonic multipotent mammary cells become lineage-restricted surprisingly early in development, with evidence for unipotency as early as E12.5 and no statistically discernable bipotency after E15.5. To gain insights into the mechanisms governing the switch from multipotency to unipotency, we used gain-of-function Notch1 mice and demonstrated that Notch activation cell autonomously dictates luminal cell fate specification to both embryonic and basally committed mammary cells. These functional studies have important implications for understanding the signals underlying cell plasticity and serve to clarify how reactivation of embryonic programs in adult cells can lead to cancer.

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Année de publication : 2017

Perrine Paul-Gilloteaux, Xavier Heiligenstein, Martin Belle, Marie-Charlotte Domart, Banafshe Larijani, Lucy Collinson, Graça Raposo, Jean Salamero (2017 Feb 1)

eC-CLEM: flexible multidimensional registration software for correlative microscopies.

Nature methods : 102-103 : DOI : 10.1038/nmeth.4170 En savoir plus

Claire François-Martin, James E Rothman, Frederic Pincet (2017 Jan 25)

Low energy cost for optimal speed and control of membrane fusion.

Proceedings of the National Academy of Sciences of the United States of America : 1238-1241 : DOI : 10.1073/pnas.1621309114 En savoir plus

Membrane fusion is the cell’s delivery process, enabling its many compartments to receive cargo and machinery for cell growth and intercellular communication. The overall activation energy of the process must be large enough to prevent frequent and nonspecific spontaneous fusion events, yet must be low enough to allow it to be overcome upon demand by specific fusion proteins [such as soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs)]. Remarkably, to the best of our knowledge, the activation energy for spontaneous bilayer fusion has never been measured. Multiple models have been developed and refined to estimate the overall activation energy and its component parts, and they span a very broad range from 20 kBT to 150 kBT, depending on the assumptions. In this study, using a bulk lipid-mixing assay at various temperatures, we report that the activation energy of complete membrane fusion is at the lowest range of these theoretical values. Typical lipid vesicles were found to slowly and spontaneously fully fuse with activation energies of ∼30 kBT Our data demonstrate that the merging of membranes is not nearly as energy consuming as anticipated by many models and is ideally positioned to minimize spontaneous fusion while enabling rapid, SNARE-dependent fusion upon demand.


Année de publication : 2016

Elodie Gazquez, Yuli Watanabe, Florence Broders-Bondon, Perrine Paul-Gilloteaux, Julie Heysch, Viviane Baral, Nadège Bondurand, Sylvie Dufour (2016 Dec 2)

Endothelin-3 stimulates cell adhesion and cooperates with β1-integrins during enteric nervous system ontogenesis.

Scientific reports : 37877 : DOI : 10.1038/srep37877 En savoir plus

Endothelin-3 (EDN3) and β1-integrins are required for the colonization of the embryonic gut by enteric neural crest cells (ENCCs) to form the enteric nervous system (ENS). β1-integrin-null ENCCs exhibit migratory defects in a region of the gut enriched in EDN3 and in specific extracellular matrix (ECM) proteins. We investigated the putative role of EDN3 on ENCC adhesion properties and its functional interaction with β1-integrins during ENS development. We show that EDN3 stimulates ENCC adhesion to various ECM components in vitro. It induces rapid changes in ENCC shape and protrusion dynamics favouring sustained growth and stabilization of lamellipodia, a process coincident with the increase in the number of focal adhesions and activated β1-integrins. In vivo studies and ex-vivo live imaging revealed that double mutants for Itgb1 and Edn3 displayed a more severe enteric phenotype than either of the single mutants demonstrated by alteration of the ENS network due to severe migratory defects of mutant ENCCs taking place early during the ENS development. Altogether, our results highlight the interplay between the EDN3 and β1-integrin signalling pathways during ENS ontogenesis and the role of EDN3 in ENCC adhesion.