# Pooled Optical Screens of Synaptic Function

> **NIH NIH R21** · BROAD INSTITUTE, INC. · 2021 · $213,750

## Abstract

Though our understanding of the protein composition of the synapse and our recognition of the involvement of
synaptic mechanisms in psychiatric disease both continue to grow, our ability to study the synaptic function of
genes is still hampered by low throughput, high overhead assays. We propose to address this need by
developing pooled screens of the effect of genetic perturbations on synaptic function in cultured neurons.
Compared to arrayed screens, pooled screens are more robust to condition-to-condition variability and are thus
better suited for studies of highly culture-dependent phenotypes such as synaptic transmission. Despite this
advantage, it has been unclear how to translate pooled screening technology from studying cell survival or growth
coupled phenotypes to dynamical functional phenotypes like those involved in neuronal function. We propose
an innovative way around this problem by harnessing new optical methods. Our approach will be to perform
barcoded genetic perturbations on a pool of cultured neurons, to perform time-resolved imaging assays of their
postsynaptic or presynaptic function, and to subsequently use multiplexed RNA or protein readout methods to
read out barcodes and match synaptic phenotypes to perturbations. Postsynaptic function will be read out using
simultaneous voltage imaging and optogenetics, while presynaptic function will be read out by monitoring vesicle
recycling with a pH sensitive fluorescent protein. The postsynaptic and presynaptic protocols are independent of
each other and constitute separate specific aims. We will extensively characterize the performance of both
assays and perform a pilot screen on the synaptic functions of 50 genes identified in Schizophrenia whole exome
sequencing studies. Accomplishing these aims is possible by innovations in expression strategies, measurement
protocols, and barcoding approaches. The chief significance of this work is to enable studies of synaptic function
to occur earlier in the discovery process when studying new families of genes. In addition, the pilot screen we
perform will generate valuable information about the basic neurobiological function of Schizophrenia associated
genes. We will validate these results with traditional patch clamp approaches, and they will serve as the
launching point for further investigations into the mechanisms of action of these genes.

## Key facts

- **NIH application ID:** 10085685
- **Project number:** 5R21MH120423-02
- **Recipient organization:** BROAD INSTITUTE, INC.
- **Principal Investigator:** Samouil Farhi
- **Activity code:** R21 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $213,750
- **Award type:** 5
- **Project period:** 2020-01-15 → 2022-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10085685

## Citation

> US National Institutes of Health, RePORTER application 10085685, Pooled Optical Screens of Synaptic Function (5R21MH120423-02). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10085685. Licensed CC0.

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