Manipulation of a genetically and spatially defined sub-population of BDNF-expressing neurons potentiates learned fear and decreases hippocampal-prefrontal synchrony in mice

摘要

The p4BDNF-ERT2CreERT2 construct selectively targets cells expressing exon IV-containing Bdnf transcripts in the vHC (p4-cells). a Schematic of injection strategy for labeling of p4-cells in the vHC. b 4OHT binds to the ERT2CreERT2 fusion protein to allow Cre/lox-mediated expression of tdTomato protein. c tdTomato protein is largely limited to the ventral dentate gyrus in animals that received injections of both p4BDNF-ERT2CreERT2 and 4OHT. d tdTomato protein expression is observed only in animals that received injections of p4BDNF-ERT2CreERT2 and 4OHT (GFP labeling from co-injections of AAV1-hSyn-GFP were used to verify injection accuracy). e Single-molecule in situ hybridization reveals expression of Cre mRNA in animals that received injections of p4BDNF-ERT2CreERT2, and tdTomato expression is restricted to animals that received injections of both p4BDNF-ERT2CreERT2 and 4OHT. f A significantly higher percentage of cells co-express Cre in animals that received injections of p4BDNF-ERT2CreERT2, in comparison to animals that received injections of 4OHT without p4BDNF-ERT2CreERT2.g A significantly higher percentage of cells co-express tdTomato mRNA in animals that received both p4BDNF-ERT2CreERT2 and 4OHT, as compared to both control groups.h Cells that express either Cre or tdTomato co-express a higher number of exon IV-containing Bdnf transcripts, as compared to cells that do not express Cre or tdTomato.i A logistic regression model trained to predict whether a cell expresses tdTomato based on number of exon IV-containing Bdnf transcripts performs with high accuracy for observed data, but not data in which number of Bdnf transcripts is randomly shuffled relative to tdTomato expression probability (left panel). Receiver operating characteristic (ROC) curves on classifier performance confirm model accuracy in real and shuffled data (right panel). j Regression classifier ROC curves for real and shuffled data (dashed line = chance)