| Abstract [eng] |
The brain's development depends on critical periods marked by heightened synaptic plasticity. Once these periods close, plasticity declines. Recent investigations underscore the potential role of local synaptic protein synthesis in regulating this process. During critical periods of plasticity, the dynamic formation and elimination of synapses rely on molecular signals denoted as "don't eat-me" and "eat-me signals, among which externalized phosphatidylserine (PS) is a known signal. However, the biochemical processes initiating synapse elimination remain unclear. To study local transcriptome changes during these periods, synaptosomes—isolated synaptic terminals—were analyzed using fluorescence-activated synaptosome sorting (FASS) to obtain excitatory synapse-enriched samples. These samples, however, have reduced ribosomal RNA (rRNA) content, complicating traditional RNA integrity assessments. A PGK1-based 5′:3′ assay was developed for reliable mRNA integrity evaluation in rRNA-depleted samples. mRNA sequencing revealed that synaptic transcripts primarily regulate cellular transport, synaptic transmission, and local protein synthesis, with dynamic changes during visual cortex development. A PS-targeting probe based on the lactadherin (MFG-E8) C2 domain was also designed to visualize and quantify exposed PS on synapses, aiding the study of synaptic pruning. This research enhances our understanding of synaptic plasticity and provides tools to study brain development and remodeling processes. |
