Exploiting the molecular diversity of the synapse to investigate neuronal communication: A guide through the current toolkit

Abstract

Chemical synapses are tiny and overcrowded environments, deeply embedded inside brain tissue and enriched with thousands of protein species. Many efforts have been devoted to developing custom approaches for evaluating and modifying synaptic activity. Most of these methods are based on the engineering of one or more synaptic protein scaffolds used to target active moieties to the synaptic compartment or to manipulate synaptic functioning. In this review, we summarize the most recent methodological advances and provide a description of the involved proteins as well as the operation principle. Furthermore, we highlight their advantages and limitations in relation to studies of synaptic transmission in vitro and in vivo. Concerning the labelling methods, the most important challenge is how to extend the available approaches to the in vivo setting. On the other hand, for those methods that allow manipulation of synaptic function, this limit has been overcome using optogenetic approaches that can be more easily applied to the living brain. Finally, future applications of these methods to neuroscience, as well as new potential routes for development, are discussed.

Anomalous diffusion of synaptic vesicles and its influences on spontaneous and evoked neurotransmission

“…Future routes of investigation will include extending the range of predictions of our model also to more complex processes such as short‐ and long‐term synaptic plasticity, but also testing if different synaptic network topologies can change the non‐linear features of neurotransmission (Schulte et al., 2018). The vast toolkit of methods now available to measure and manipulate synaptic transmission will make it feasible to achieve such aims in the near future (Lamanna, Ferro, et al., 2022). We hope that our computational results will foster the acquisition of novel experimental evidence to experimentally prove the relationship among these players, as well as their effects on neuronal communication.…”

Editorial: Recent advances in measuring and controlling synaptic communication

“…The morpho-functional investigation of the synapse has always been hindered by its tiny size and high density of molecular elements, but specific technological and methodological advances helped us to reduce these limitations. As the matter of fact, in recent years, we have witnessed the continuous development of new methods allowing measuring and controlling synaptic activation both in vitro and in vivo (Lamanna et al, 2022 ). These include new genetically encoded sensors of synaptic exo-endocytosis (Ferro et al, 2017 ; Liu et al, 2021 ) and neurotransmitter release (Helassa et al, 2018 ; Patriarchi et al, 2018 ), but also engineered synaptic proteins able to control synaptic transmission (Won et al, 2021 ).…”

“…All these methodological advances are likely to generate unprecedented knowledge about the dynamics of synaptic transmission and plasticity at several levels of the nervous system. Nevertheless, in most cases, the implementation of these new methods remains technically demanding, likely due to the high complexity of their operating principle (Glasgow et al, 2019 ; Lamanna et al, 2022 ). Hence, it would be worth refining and potentiating these tools to extend the range of experimental settings for their application.…”