Project description:Proprioceptive neurons (PNs) are essential for the proper execution of all our movements by providing muscle sensory feedback to the central motor network. Here, using deep single cell RNAseq of adult PNs coupled with advanced virus- and genetic tracings, we have molecularly identified the 3 main types of PNs (Ia, Ib and II) and unexpectedly found that they segregate into 8 subgroups. Our data further reveal a highly sophisticated organization of PNs into discrete sensory input channels with distinct spatial distribution, innervation patterns and molecular profiles, that together contribute to the sensory monitoring of complex motor behavior. Moreover, while Ib- and II-PN subtypes are specified around birth, Ia-PN subtypes diversify later along with increased motor activity and show versatility in the adult following exercise training, suggesting adaptive proprioceptive function.
Project description:Our objective was to evaluate the gene expression changes occuring in early sensory neuron development that were lost in the absence of Tmem184b and restored upon its reintroduction into mutant neurons in culture.
Project description:Integration of nutritional, microbial and inflammatory events along the gut-brain axis can alter bowel physiology and organism behaviour. The principal neural unit in the bowel encoding these stimuli is the visceral sensory neuron with endings at the mucosa, intramurally and along mesenteric blood vessels. Sensory neurons activate reflex pathways and give rise to conscious sensation, however, the diversity and division of function within these neurons is poorly understood. The identification of signalling pathways contributing to visceral sensation is constrained by the current paucity of molecular markers. Here we overcome these limitations by comprehensive transcriptomic profiling and unsupervised clustering of single colonic sensory neurons revealing 7 classes characterised from both lumbar splanchnic (LSN) and pelvic nerves (PN). We identify and classify neurons based on novel marker genes, confirm translation of patterning to protein expression and show subtype-selective differential agonist activation, describing sensory diversity encompassing all modalities of colonic neuronal sensitivity.
Project description:Primary somatosensory neurons specialize in transmitting distinct types of sensory information through differences in cell size, myelination, and the expression of various receptors and ion channels, which together define their transcriptional and functional identity. By profiling sensory ganglia at single-cell resolution, we find that the different somatosensory neuronal subtypes undergo a similar transcriptional response to peripheral nerve injury that both promotes axonal regeneration and suppresses cell identity. This transcriptional reprogramming, which is not observed in non-neuronal cells from sensory ganglia, resolves over a similar time course as target reinnervation and is associated with the restoration of original cell identity. Injury-induced transcriptional reprogramming requires ATF3, a transcription factor which is induced rapidly after injury and necessary for axonal regeneration and functional recovery. Our findings suggest that the transcription factors induced early after peripheral sensory neuron injury promote their transcriptional and functional metamorphosis, analogous to their known roles in reprogramming cell fate.