Postsynaptic synucleins mediate endocannabinoid signaling.
Endocannabinoids are among the most powerful modulators of synaptic transmission throughout the nervous system, and yet little is understood about the release of endocannabinoids from postsynaptic compartments. Here we report an unexpected finding that endocannabinoid release requires synucleins, key contributors to Parkinson's disease. We show that endocannabinoids are released postsynaptically by a synuclein-dependent and SNARE-dependent mechanism. Specifically, we found that synuclein deletion blocks endocannabinoid-dependent synaptic plasticity; this block is reversed by postsynaptic expression of wild-type but not of mutant alpha-synuclein. Whole-cell recordings and direct optical monitoring of endocannabinoid signaling suggest that the synuclein deletion specifically blocks endocannabinoid release. Given the presynaptic role of synucleins in regulating vesicle lifecycle, we hypothesize that endocannabinoids are released via a membrane interaction mechanism. Consistent with this hypothesis, postsynaptic expression of tetanus toxin light chain, which cleaves synaptobrevin SNAREs, also blocks endocannabinoid-dependent signaling. The unexpected finding that endocannabinoids are released via a synuclein-dependent mechanism is consistent with a general function of synucleins in membrane trafficking and adds a piece to the longstanding puzzle of how neurons release endocannabinoids to induce synaptic plasticity.
View details for DOI 10.1038/s41593-023-01345-0
View details for PubMedID 37248337
Mettl14-mediated m6A modification ensures the cell-cycle progression of late-born retinal progenitor cells.
View details for DOI 10.1016/j.celrep.2023.112596
Motor learning selectively strengthens cortical and striatal synapses of motor engram neurons.
Learning and consolidation of new motor skills require plasticity in the motor cortex and striatum, two key motor regions of the brain. However, how neurons undergo synaptic changes and become recruited during motor learning to form a memory engram remains unknown. Here, we train mice on a motor learning task and use a genetic approach to identify and manipulate behavior-relevant neurons selectively in the primary motor cortex (M1). We find that the degree of M1 engram neuron reactivation correlates with motor performance. We further demonstrate that learning-induced dendritic spine reorganization specifically occurs in these M1 engram neurons. In addition, we find that motor learning leads to an increase in the strength of M1 engram neuron outputs onto striatal spiny projection neurons (SPNs) and that these synapses form clusters along SPN dendrites. These results identify a highly specific synaptic plasticity during the formation of long-lasting motor memory traces in the corticostriatal circuit.
View details for DOI 10.1016/j.neuron.2022.06.006
View details for PubMedID 35809573
Epitranscriptomic m(6)A modification controls the development of late-born retinal progenitor cells
ASSOC RESEARCH VISION OPHTHALMOLOGY INC. 2022
View details for Web of Science ID 000844401304034
Identification of cis-regulatory modules for adeno-associated virus-based cell type-specific targeting in the retina and brain.
The Journal of biological chemistry
Adeno Associated Viruses (AAVs) targeting specific cell types are powerful tools for studying distinct cell types in the central nervous system (CNS). Cis-regulatory modules (CRMs), e.g., enhancers, are highly cell type-specific and can be integrated into AAVs to render cell type specificity. Chromatin accessibility has been commonly used to nominate CRMs, which have then been incorporated into AAVs and tested for cell type-specificity in the CNS. However, chromatin accessibility data alone cannot accurately annotate active CRMs, as many chromatin-accessible CRMs are not active and fail to drive gene expression in vivo. Using available large-scale datasets on chromatin accessibility, such as those published by the ENCODE project, here we explored strategies to increase efficiency in identifying active CRMs for AAV-based cell type-specific labeling and manipulation. We found that pre-screening of chromatin-accessible putative CRMs based on the density of cell type-specific transcription factor binding sites (TFBSs) can significantly increase efficiency in identifying active CRMs. In addition, generation of synthetic CRMs by stitching chromatin-accessible regions flanking cell type-specific genes can render cell type-specificity in many cases. Using these straightforward strategies, we generated AAVs that can target the extensively studied interneuron and glial cell types in the retina and brain. Both strategies utilize available genomic datasets and can be employed to generate AAVs targeting specific cell types in CNS without conducting comprehensive screening and sequencing experiments, making a step forward in cell type-specific research.
View details for DOI 10.1016/j.jbc.2022.101674
View details for PubMedID 35148987