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Group Broillet

Marie-Christine Broillet, MER, PD

Marie-Christine Broillet received her PhD in 1993 from the University of Lausanne for research on renal K channels performed with Prof. Jean-Daniel Horisberger. In 1998, After a post-doctoral training with Prof. Stuart Firestein at Columbia University (New York) where She studied olfactory cyclic nucleotide-gated channels, She joined the Department of Pharmacology and Toxicology of the UNIL as a START fellow to create and lead her own research group working on ion channels and membrane receptors in olfactory neurons.

Keywords: olfaction, taste, pheromones, ion channels, GPCR, imaging, electrophysiology microscopy.

 

Studies using gene-targeted mice have revealed the presence of multiple olfactory subsystems. Indeed, in mammals, the reception of olfactory cues seems to be primarily mediated by chemosensory neurons localized in distinct nasal compartments: the main olfactory epithelium, the vomeronasal organ (VNO) and the septal organ. Based on its expression in mature sensory cells of these compartments, the olfactory marker protein (OMP) is generally considered as indicative of mature olfactory sensory neurons. In mice, OMP-positive neurons have also been identified recently in the so-called Grueneberg ganglion, a ganglion of unknown function at the tip of the nasal cavity, found in different mammalian species including humans.

Cyclic nucleotide-gated (CNG) channels are nonselective cation channels first identified in retinal photoreceptors and olfactory neurons. They are opened by the direct binding of the cyclic nucleotides cAMP and cGMP. The function of CNG channels has been established in retinal photoreceptors (rods and cones) and in main olfactory neurons where six different genes encoding four A subunits (A1 to A4) and two B subunits (B1 and B3) give rise to three different ion channels. Through the direct gating of nitric oxide, we have been able to show that CNGA4 subunits can form functional homomeric channels in VNO neurons but their physiological role in these cells remains to be identified. CNG channels gated by NO or by cyclic nucleotides and highly permeable to calcium, are good candidates for transducing chemosignals received by olfactory sensory neurons at different stages in their development.

Our laboratory currently investigates and compares the development and chemosensory properties of the different olfactory subsystems focusing on the vomeronasal organ and the Grueneberg ganglion.

figure.jpg

Calcium imaging on HEK cells transduced with a pheromone receptor.


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