Automated and controlled mechanical stimulation and functional imaging in vivo in C. elegans.

Yongmin Cho,Hyundoo Hwang,William R Schafer,Laura J Grundy,Hang Lu,Daniel A Porto

doi:10.1039/c7lc00465f

Yongmin Cho, Hyundoo Hwang + Show 4 more

Open Access

https://doi.org/10.1039/c7lc00465f

Copy DOI

Abstract

C. elegans is a useful genetic model system for investigating mechanisms involved in sensory behavior which are potentially relevant to human diseases. While utilities of advanced techniques such as microfluidics have accelerated some areas of C. elegans sensory biology such as chemosensation, studies of mechanosensation conventionally require immobilization by glue and manual delivery of stimuli, leading to low experimental throughput and high variability. Here we present a microfluidic platform that precisely and robustly delivers a wide range of mechanical stimuli and can also be used in conjunction with functional imaging and optical interrogation techniques. The platform is fully automated, thereby greatly enhancing the throughput and robustness of experiments. We show that the behavior of the well-known gentle and harsh touch neurons and their receptive fields can be recapitulated. Using calcium dynamics as a read-out, we demonstrate its ability to perform a drug screen in vivo. We envision that this system will be able to greatly accelerate the discovery of genes and molecules involved in mechanosensation and multimodal sensory behavior, as well as the discovery of therapeutics for related diseases.

Highlights

C. elegans is a useful genetic model system for investigating mechanisms involved in sensory behavior which are potentially relevant to human diseases
We present a microfluidic platform for delivering robust and precise mechanical stimuli to C. elegans by using pneumatically actuated structures
To demonstrate the utility of the system, we examined the responses of the classic gentle touch receptor neurons (AVM, Fig. 1 The microfluidic platform can robustly deliver a mechanical stimulus and allow imaging of calcium responses in C. elegans mechanoreceptor neurons. (A) An integrated system for automated functional imaging of C. elegans in microfluidic devices

Summary

Introduction

C. elegans is a useful genetic model system for investigating mechanisms involved in sensory behavior which are potentially relevant to human diseases. There is still an unmet need for a robust and automatable experimental platform to deliver a wide range of mechanical stimuli (e.g. additional modes of stimulating gentle touch neurons and stimuli strong enough to stimulate harsh touch neurons). To address this need, we present a microfluidic platform for delivering robust and precise mechanical stimuli to C. elegans by using pneumatically actuated structures. The device is fully automated, minimizing human variability and improving experimental throughput It is fully compatible with fluorescence imaging of the calcium dynamics of neurons, which enables mechanistic interrogations as well as high-throughput genetic or drug screens. We demonstrate the design and utility of such a system in the context of a pilot drug screen

Methods

Results

Conclusion