Development of optogenetic molecular probe for inhibition of synaptic transmission, and detection protocol for the COVID-19

Abstract

Spatiotemporal control of brain activity by optogenetics has emerged as an essential tool to study brain function. For silencing the brain activity, optogenetic probes, such as halorhodopsin and Archaerhodopsin, inhibit transmitter release indirectly by hyperpolarizing the membrane potentials. However, those probes cause undesirable ionic imbalance and rebound spikes. Moreover, they are not applicable to use in non-excitable glial cells. Here, we engineered Opto-vTrap, a light-inducible and reversible inhibition system to temporarily trap the transmitter-containing vesicles from exocytotic release. Light-activation of Opto-vTrap caused a full vesicle-clusterization and complete inhibition of exocytosis within one minute, which recovered within 30 minutes after light-off. We found a significant reduction of synaptic- and glio-transmission upon activation of Opto-vTrap in acute brain slices. Opto-vTrap significantly inhibited hippocampus-dependent memory retrieval with a full recovery within an hour. We propose the Opto-vTrap as a next-generation optogenetic silencer to control brain activity and behavior with minimal confounding effects.And recently, COVID-19 has spread rapidly all over the world. Although many commercial test kits are available, detailed scientific evaluation and verification are lacking, making the public vulnerable to fear of false-positive results. In this time of crisis, a low-cost, easy-access protocol for early detection of this virus is desperately needed. Here, we established a qRT-PCR-based assay protocol composed of easy specimen self-collection including non-invasive saliva self-sampling, RNA purification, and SYBR Green-based qRT-PCR with optimized-primer sets for SARS-COV-2 detection. For non-biased automatic risk evaluation, we developed a scalable formula based on a logistic classification model to assess the degree of positivity for the presence of SARS-COV-2. Our newly developed protocol should be helpful for a first-hand screening of the asymptomatic virus-carriers for further prevention of transmission. Furthermore, a newly established risk assessment formula can be applied to a large-scale diagnosis in major health institutions and agencies around the world.