Co-culture of Glutamatergic Neurons and Pediatric High-Grade Glioma Cells Into Microfluidic Devices to Assess Electrical Interactions

Summary

Recent works uncover the neuronal impact on high-grade pediatric glioma (pHGG) cells and their reciprocal interactions. The present work shows the development of an in vitro model co-culturing pHGG cells and glutamatergic neurons and recorded their electrophysiological interactions to mimic those interactivities.

Abstract

Pediatric high-grade gliomas (pHGG) represent childhood and adolescent brain cancers that carry a rapid dismal prognosis. Since there is a need to overcome the resistance to current treatments and find a new way of cure, modeling the disease as close as possible in an in vitro setting to test new drugs and therapeutic procedures is highly demanding. Studying their fundamental pathobiological processes, including glutamatergic neuron hyperexcitability, will be a real advance in understanding interactions between the environmental brain and pHGG cells. Therefore, to recreate neurons/pHGG cell interactions, this work shows the development of a functional in vitro model co-culturing human-induced Pluripotent Stem (hiPS)-derived cortical glutamatergic neurons pHGG cells into compartmentalized microfluidic devices and a process to record their electrophysiological modifications. The first step was to differentiate and characterize human glutamatergic neurons. Secondly, the cells were cultured in microfluidic devices with pHGG derived cell lines. Brain microenvironment and neuronal activity were then included in this model to analyze the electrical impact of pHGG cells on these micro-environmental neurons. Electrophysiological recordings are coupled using multielectrode arrays (MEA) to these microfluidic devices to mimic physiological conditions and to record the electrical activity of the entire neural network. A significant increase in neuron excitability was underlined in the presence of tumor cells.

Introduction

Pediatric high-grade gliomas (pHGG) exhibit an extended genotypic and phenotypic diversity depending on patient age, tumor anatomical location and extension, and molecular drivers¹. They are aggressive brain tumors that are poorly controlled with the currently available treatment options and are the leading cause of death related to brain cancers in children and adolescents². So, more than 80% of patients are relapsing within 2 years after their diagnosis, and their median survival is 9-15 months, depending on brain locations and driver mutations. The absence of curative treatment is the primary urge for laboratory resea....

Protocol

For this protocol, the accreditation number related to the use of human materials is DC-2020-4203.

1. Microfluidic device fabrication, preparation and treatment

1. Fabricate SU-8 molds using conventional photolithography techniques¹⁸.
   NOTE: For this purpose, two photolithography masks have been designed to construct two layers of photoresist structures on silicon wafer substrate and a thin SU-8 2005 photoresist layer (3.2 µm high and 6 ± 1 µm wide) that defines asymmetric microgrooves under the patterning of main channels made in SU-8 2100 (200 µm high, 1 mm wide, and 13 mm long) (....

Results

Before studying electrical interactions between glutamatergic neurons and glioma cells, hiPS-derived cortical glutamatergic neurons were characterized to validate the feasibility of culturing them in microfluidic devices (Figure 1A). Their characterization was assessed using Nestin, Sox2, mGlurR2 (metabotropic Glutamate Receptors 2), and vGLUT1 immunostaining, represented in Figure 1A(2-7). As Nestin is an intermediate f.......

Discussion

This work describes an accurate functional in vitro model to evaluate the interaction between human hiPS-derived cortical glutamatergic neurons and brain tumoral cells in microfluidic devices. One of the crucial steps in the present protocol was the hiPS differentiation in glutamatergic neurons, which was confirmed by the decrease of Nestin and Sox2 immunofluorescent staining and simultaneous appearance of mGluR2 and vGLUT1 staining. Nevertheless, few neural progenitors remained as only half of the glutamatergic.......

Materials

Name	Company	Catalog Number	Comments
256MEA100/30iR-ITO-w/o	MCS	256MEA100/30iR-ITO-w/o
40 µm probe for Scepter counter	Dutscher	53750
60 µm probe for Scepter counter	Dutscher	51999
Accutase	Sigma	A6964
Ala -Gln (GlutaMAX)	Sigma	G8541
Axel Observer 7 Microscope	Zeiss	431007-9904-000
Cell culture flask with cap with filter membrane 70 mL Falcon®	Dutscher	353109
Class II Biological Safety Cabinet	Thermo Scientific	HERASafe type KS12
Colibri 7 LED	Zeiss	4230529710-000
Cortical Glutamatergic Neurons	BrainXell	BX-0300
DMEM/F-12 (1:1) GlutaMAX	Gibco	31331-028
DMEM/F12 Medium	Sigma	D8437
DPBS 1X	Dutscher	L0615-500
EasYFlaskTM cell culture flasks 75cm3	Nunc	156499
Foetal Bovine Serum (FBS)	Dutscher	500105
GDNF	Peprotech	450-10
Geltrex	Life Technologies	A1413201
Human BDNF	Peprotech	450-02
Incubator	Memmert	IC0150med
MCS InterFace Boarder	MCS	181205-MEA2100-11240
MEA2100	MCS	181205-MEA2100-11240
Micropipette P10	Sartorius	LH-729020
Micropipette P100	Sartorius	LH-729050
Micropipette P1000	Sartorius	LH-729070
Micropipette P200	Sartorius	LH-729060
Microtube Eppendorf 1,5 ml Safe-Lock	Dutscher	33290
MultiChannel Experimenter	MCS	-
N2 Supplement-A	StemCell	7152
Neurobasal Medium	Life Technologies	21103049
Neurocult SM1 neuronal supplement	StemCell	5711
Non filter tip 0.1 - 10 µl ClearLine® sterile in removable-lid rack	Dutscher	030570ACL
Non filter tip 1 - 200 µl ClearLine® sterile in removable-lid rack	Dutscher	032260CL
Non filter tip 50 - 1250 µl ClearLine® sterile in removable-lid rack	Dutscher	134760CL
Non-essential amino acids (NEAA) without L-glutamine	Dutscher	X0557-100
Pipeteur Pipet-Aid XP Gravity	Drummond	4000202/4038202
Pipette for cell culture 10 mL Falcon®	Dutscher	357551
Pipette for cell culture 5 mL Falcon®	Dutscher	357543
Plaque chauffante (CultureTemp)	Belart	370151000
Poly-D-Lysine	Sigma	P6407
Primovert microscope	Zeiss	415510-1100-000
Scepter (Handheld Automated Cell Counter)	Millipore	PHCC00000
TGF-β1	Peprotech	100-21C
Tube with conical bottom 15 mL (bulk) Falcon®	Dutscher	352096
Tube with conical bottom 50 mL (bulk) Falcon®	Dutscher	352070