Guest Speaker: Professor Jean Rossier - ‘Cortical fast-spiking parvalbumin interneurons enwrapped in the perineuronal net express the metallopeptidases Adamts8, Adamts15 and Neprilysin’


The in situ hybridization Allen Mouse Brain Atlas was mined for proteases expressed in the somatosensory cerebral cortex. Among the 480 genes coding for protease/peptidases, only 3 were found enriched in cortical interneurons: Adamts8 and Adamts15 belonging to the class of metzincin proteases involved in reshaping the perineuronal net (PNN) and Mme encoding for Neprilysin, the enzyme degrading amyloid β−peptides. The pattern of expression of metalloproteases (MP) was analyzed by single cell RT multiplex PCR after patch-clamp and was compared with the expression of 10 canonical interneurons markers and 12 additional genes from the Allen Atlas. Clustering of these genes by K-means algorithm displays five distinct clusters. Among these 5 clusters, two fast spiking (FS) interneurons clusters expressing the calcium-binding protein Pvalb were identified, one co-expressing Pvalb with Sst (PV-Sst) and another co-expressing Pvalb with three metallopeptidases Adamts8, Adamts15 and Mme (PV-MP). PV-MP interneurons were found surrounded by PNN while the one expressing Sst, PV-Sst were not. These observations will be discussed in view of current hypothesis on brain plasticity, critical period and long term mem