A High-Throughput Automated Microfluidic Platform for Calcium Imaging of Taste Sensing.

Yi-Hsing Hsiao,Chia-Hsien Hsu,Chihchen Chen

doi:10.3390/molecules21070896

Yi-Hsing Hsiao, Chia-Hsien Hsu + Show 1 more

Open Access

https://doi.org/10.3390/molecules21070896

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Abstract

The human enteroendocrine L cell line NCI-H716, expressing taste receptors and taste signaling elements, constitutes a unique model for the studies of cellular responses to glucose, appetite regulation, gastrointestinal motility, and insulin secretion. Targeting these gut taste receptors may provide novel treatments for diabetes and obesity. However, NCI-H716 cells are cultured in suspension and tend to form multicellular aggregates, preventing high-throughput calcium imaging due to interferences caused by laborious immobilization and stimulus delivery procedures. Here, we have developed an automated microfluidic platform that is capable of trapping more than 500 single cells into microwells with a loading efficiency of 77% within two minutes, delivering multiple chemical stimuli and performing calcium imaging with enhanced spatial and temporal resolutions when compared to bath perfusion systems. Results revealed the presence of heterogeneity in cellular responses to the type, concentration, and order of applied sweet and bitter stimuli. Sucralose and denatonium benzoate elicited robust increases in the intracellular Ca2+ concentration. However, glucose evoked a rapid elevation of intracellular Ca2+ followed by reduced responses to subsequent glucose stimulation. Using Gymnema sylvestre as a blocking agent for the sweet taste receptor confirmed that different taste receptors were utilized for sweet and bitter tastes. This automated microfluidic platform is cost-effective, easy to fabricate and operate, and may be generally applicable for high-throughput and high-content single-cell analysis and drug screening.

Highlights

The gustatory system of mammals can distinguish thousands of substrates when a substrate in the oral cavity biochemically binds to taste receptors in taste bud cells [1,2]
The activation of sweet taste receptors by glucose in gut cells is known to elevate the concentration of intracellular Ca2+
We focused on studying Ca2+ responses and the potential roles of NCI-H716 cells in diabetes

Summary

Introduction

The gustatory system of mammals can distinguish thousands of substrates when a substrate in the oral cavity biochemically binds to taste receptors in taste bud cells [1,2]. Sweet taste receptors are expressed in human gut cells and they can sense tastes using the same mechanism as the human tongue [5,6,7]. Evidence has suggested that sweet taste receptors expressed in. The activation of sweet taste receptors by glucose in gut cells is known to elevate the concentration of intracellular Ca2+. GLP-1 may, in turn, cause the subsequent release of insulin [8,14,15,16]. Modulating the secretion of GLP-1 molecules from “taste cells” in the gut may provide an important model for sweet taste stimulation, especially on meal-induced insulin secretion [14,17,18,19].

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