Functional and transcriptional characterization of complex neuronal co-cultures

Heather A Enright,Sandra K G Peters,Kristen S Kulp,David A Soscia,Joanne J Osburn,Bryan Petkus,Gabriela G Loots,Nicholas R Hum,Elizabeth K Wheeler,Aimy Sebastian,Doris Lam,Jose Cadena,Nicholas O Fischer,Ana Paula Sales

doi:10.1038/s41598-020-67691-2

Heather A Enright, Sandra K G Peters + Show 12 more

Open Access

https://doi.org/10.1038/s41598-020-67691-2

Copy DOI

Abstract

Brain-on-a-chip systems are designed to simulate brain activity using traditional in vitro cell culture on an engineered platform. It is a noninvasive tool to screen new drugs, evaluate toxicants, and elucidate disease mechanisms. However, successful recapitulation of brain function on these systems is dependent on the complexity of the cell culture. In this study, we increased cellular complexity of traditional (simple) neuronal cultures by co-culturing with astrocytes and oligodendrocyte precursor cells (complex culture). We evaluated and compared neuronal activity (e.g., network formation and maturation), cellular composition in long-term culture, and the transcriptome of the two cultures. Compared to simple cultures, neurons from complex co-cultures exhibited earlier synapse and network development and maturation, which was supported by localized synaptophysin expression, up-regulation of genes involved in mature neuronal processes, and synchronized neural network activity. Also, mature oligodendrocytes and reactive astrocytes were only detected in complex cultures upon transcriptomic analysis of age-matched cultures. Functionally, the GABA antagonist bicuculline had a greater influence on bursting activity in complex versus simple cultures. Collectively, the cellular complexity of brain-on-a-chip systems intrinsically develops cell type-specific phenotypes relevant to the brain while accelerating the maturation of neuronal networks, important features underdeveloped in traditional cultures.

Highlights

Brain-on-a-chip systems are designed to simulate brain activity using traditional in vitro cell culture on an engineered platform
In vitro neuronal cultures for both simple and complex systems were established on Microelectrode array (MEA) and routinely monitored using electrophysiology over the course of 31 days
Our study aimed to identify the morphological, molecular, and functional differences between a simple neuronal culture and a co-culture system comprised of neurons, astrocytes, and oligodendrocytes seeded in ratios relevant to the postnatal b rain[27,28,29]

Summary

Introduction

Brain-on-a-chip systems are designed to simulate brain activity using traditional in vitro cell culture on an engineered platform. In vitro brain-on-a-chip platforms have emerged as useful tools to model brain activity to aid in evaluating neuronal outcomes for new drugs and toxicants, in addition to elucidating disease mechanisms[1,2,3]. Electrophysiological features of rodent-derived neural networks, established with both glutamatergic and GABAergic neurons, have been well characterized using dissociated neurons from primary cells or derived from neural stem cells[23,24,25] These systems most often utilize mono-cultures of neurons or co-cultures with astrocytes, which do not fully mimic the cellular complexity of the brain and may misrepresent neuronal responses when evaluating drugs and toxicants relative to in vivo testing[26]. We anticipate these findings will extend to human-based neuronal cultures and will more accurately reproduce the drug responses observed in in vivo systems

Methods

Results

Conclusion