Neuronal networks of sleep states

The Lyon Sleep Lab is an international leader for the identification and description of the neuronal networks underlying the sleep-waking cycle, with a focus on paradoxical (REM) sleep (hypertext link to Luppi et al, 2017) during which dreams and oniric activities mainly occur.

Over the last years, we worked on different populations of hypothalamic and brainstem PS-executive neurons and complex networks they form together. This was done by adding to standard techniques in the sleep field as polysomnography and functional neuroanatomy, state-of-art molecular methods (i.e. KO and KI transgenic mice, optogenetics, chemogenetics, AAVs, shRNAs …) allowing to timely manipulate neurons of interest in behaving rodents.

Illustrating our on-going research strategy, we recently discovered in rats two critical brainstem cell populations for REM sleep expression. Indeed, their respective genetic inactivation using specific shRNAs severely impairs REM sleep with the irreversible loss of muscle atonia, a pathognomonic sign of this sleep state (hypertext link to Valencia Garcia et al, 2017, 2018a) and the abnormal occurrence of uncontrolled motor activities likely reflecting oniric behaviors during dreams. This basic research led us to validate preclinical models recapitulating in rodents, the human REM sleep Behavior Disorder, a prodromal parasomnia of Parkinson’s Disease (hypertext links to Valencia Garcia et al, 2018b, c; see also hypertext link to the Project 5).

To pursue this successful strategy, our next main objective is to clarify the respective contribution of the brain nuclei we discovered in the natural alternation of the vigilance states, with a focus on  brainstem and hypothamamic interconnections underlying REM sleep generation and regulation.

We are convinced that virus transfection is a tool of choice for that ambitious goal, because of the extrem neuronal heterogeneity of the brain. Hence, we use an innovative and powerful line of TRAP2-red transgenic mice (hypertext link to Lee et al, 2020) allowing, under tamoxifen treatment, the permanent expression of both cre-recombinase and reporter protein mCherry only in neurons expressing c-Fos (i.e. TRAPed) during a given physiological paradigm (i.e. REM sleep deprivation, recovery, enriched environment, total sleep deprivation etc ). By this mean, we are able to unravel for TRAPed neurons their specific transcriptomic and connectomic profiles as their physiological contribution to sleep, by developing targeted droplet-based single-cell RNA-sequencing, viral-mediated tract-tracing and chemo/optogenetics or targeted cellular lesion with variety of dedicated cre-dependant AAVs (see also hypertext link to the Project 4).