Project description:This experiment was designed to compare the transcriptomic differences between two parvalbumin (PV) interneuron population of the mouse brain. These two populations have the same embryological origin and share several neurochemical and electrophysiological properties, but differ in their ability to express the glial cell line-derived neurotrophic factor GDNF (negative in cortex and positive in striatum). Two different reporters for PV expressing cells were used: i) a constitutive tdTomato gene inserted in the Pvalb locus, and ii) a PV-Cre; tdTomato model in which fluorescent cells are PV cells expressing Cre recombinase. The comparative gene expression analysis between PV neurons captured from striatum and cortex allowed unraveling differential molecular characteristics of GDNF-synthesizing striatal PV interneurons and their potential role in endogenous GDNF modulation. The specific expression of several genes of interest in the striatal PV interneurons has been validated by other methods (real-time RT-PCR, in situ hibridization, immunohistochemistry).
Project description:Alzheimer’s disease is a debilitating neurodegenerative disorder with no cure and few treatment options. In early stages of Alzheimer’s disease, impaired metabolism and functional connectivity of the retrosplenial cortex strongly predict future cognitive impairments. Therefore, understanding Alzheimer’s disease-related deficits in the retrosplenial cortex is critical for understanding the origins of cognitive impairment and identifying early treatment targets. Using the 5xFAD mouse model, we discovered early, sex-dependent alterations in parvalbumin-interneuron transcriptomic profiles. This corresponded with impaired parvalbumin-interneuron activity, which was sufficient to induce cognitive impairments and dysregulate retrosplenial functional connectivity. In fMRI scans from patients with mild cognitive impairment and Alzheimer’s disease, we observed a similar sex-dependent dysregulation of retrosplenial cortex functional connectivity and, in post-mortem tissue from subjects with Alzheimer’s disease, a loss of parvalbumin interneurons. Reversal of cognitive deficits by stimulation of parvalbumin interneurons in the retrosplenial cortex suggests that this may serve as a promising novel therapeutic strategy.
Project description:Alzheimer’s disease is a debilitating neurodegenerative disorder with no cure and few treatment options. In early stages of Alzheimer’s disease, impaired metabolism and functional connectivity of the retrosplenial cortex strongly predict future cognitive impairments. Therefore, understanding Alzheimer’s disease-related deficits in the retrosplenial cortex is critical for understanding the origins of cognitive impairment and identifying early treatment targets. Using the 5xFAD mouse model, we discovered early, sex-dependent alterations in parvalbumin-interneuron transcriptomic profiles. This corresponded with impaired parvalbumin-interneuron activity, which was sufficient to induce cognitive impairments and dysregulate retrosplenial functional connectivity. In fMRI scans from patients with mild cognitive impairment and Alzheimer’s disease, we observed a similar sex-dependent dysregulation of retrosplenial cortex functional connectivity and, in post-mortem tissue from subjects with Alzheimer’s disease, a loss of parvalbumin interneurons. Reversal of cognitive deficits by stimulation of parvalbumin interneurons in the retrosplenial cortex suggests that this may serve as a promising novel therapeutic strategy.
Project description:Since many years, we are interested in the regulation of the intraneuronal chloride concentration. We were the first group reporting a full knockout of the KCl-co-transporter KCC2, which dies immediately after birth due to respiratory failure. Notably, KCC2 loss-of-function mutations are associated with inherited febrile seizures, severe genetic generalized epilepsy and epilepsy of infancy with migrating focal seizures. Here, we used our floxed line to study the consequences of the disruption of KCC2 within parvalbumin-positive interneurons in mice. Remarkably, this leads to the disinhibition of PV-positive interneurons as evidenced by a decrease of E-S-Coupling and an increase in the sIPSC frequency. Nevertheless, these mice develop fatal epilepsy with progressive loss of parvalbumin-positive interneurons thus increasing network excitability.
Project description:Our group has reported that the histone methyltransferase DOT1L is necessary for proper cortical plate development and layer distribution of glutamatergic neurons, however, its specific role on cortical interneuron development has not yet been explored. Here, we demonstrate that DOT1L affects interneuron development in a cell-autonomous manner. Deletion of Dot1l in MGE-derived interneuron precursor cells results in an overall reduction and altered distribution of GABAergic interneurons in the cortical plate at postnatal day (P) 0. Furthermore, we observed an altered proportion of GABAergic interneurons in the cortex and striatum at P21 with a significant decrease in Parvalbumin (PVALB)-expressing interneurons. Altogether, our results indicate that reduced numbers of cortical interneurons upon DOT1L deletion results from altered postmitotic differentiation/maturation.
Project description:People with schizophrenia show hyperactivity in the ventral hippocampus (vHipp) and we have previously demonstrated distinct behavioral roles for vHipp cell populations. Here, we test the hypothesis that parvalbumin (PV) and somatostatin (SST) interneurons differentially innervate and regulate hippocampal pyramidal neurons based on their projection target. First, we use eGRASP to show that PV-positive interneurons form a similar number of synaptic connections with pyramidal cells regardless of their projection target while SST-positive interneurons preferentially target nucleus accumbens (NAc) projections. To determine if these anatomical differences result in functional changes, we used in vivo opto-electrophysiology to show that SST cells also preferentially regulate the activity of NAc-projecting cells. These results suggest vHipp interneurons differentially regulate that vHipp neurons that project to the medial prefrontal cortex (mPFC) and NAc. Characterization of these cell populations may provide potential molecular targets for the treatment schizophrenia and other psychiatric disorders associated with vHipp dysfunction.
Project description:We developed an affinity purification approach to isolate tagged nuclei in mice (similar to INTACT; [Deal R.B. and Henikoff S. A simple method for gene expression and chromatin profiling of individual cell types within a tissue. Dev. Cell 18,1030-1040. (2010)]) and used it to characterize genome-wide patterns of transcription, DNA methylation, and chromatin accessibility in 3 major neuron classes of the neocortex (excitatory pyramidal neurons, parvalbumin (PV)-positive GABAergic interneurons, and vasoactive intestinal peptide (VIP)-positive GABAergic interneurons). By combining cell purification and integrative analysis, our findings relate the phenotypic and functional complexity of neocortical neurons to their underlying transcriptional and epigenetic diversity. RNA-seq, MethylC-seq, ATAC-seq, and ChIP-seq for histone modifications using INTACT-purified nuclei from the mouse neocortex
Project description:We provide an annotated cDNA clone collection which is particularly suitable for transcriptomic analysis in the mouse brain. Using it on microarrays, we compared the transcriptome of EGFP positive and negative cells in a parvalbumin-egfp transgenic background and showed that more than 30 % of clones are differentially expressed. Our clone collection will be a useful resource for the study of the transcriptome of single cell types. Keywords: Cell type comparison Comparison between fluorescent and non-fluorescent cells isolated from the visual cortex of parvalbumin-egfp transgenic mice. Using five biological replicates with a dye-swap strategy (10 hybridisations).