A Recombinant Human Pluripotent Stem Cell Line Stably Expressing Halide-Sensitive YFP-I152L for GABAAR and GlyR-Targeted High-Throughput Drug Screening and Toxicity Testing

Abstract

GABAARs and GlyRs are considered attractive drug targets for therapeutic intervention and are also increasingly recognized in the context of in vitro neurotoxicity (NT) and developmental neurotoxicity (DNT) testing. However, systematic human-specific GABAAR and GlyR-targeted drug screening and toxicity testing is hampered due to lack of appropriate in vitro models that express native GABAARs and GlyRs. We have established a human pluripotent stem cell line (NT2) stably expressing YFP-I152L, a halide-sensitive variant of yellow fluorescent protein (YFP), allowing for fluorescence-based functional analysis of chloride channels. Upon stimulation with retinoic acid, NT2 cells undergo neuronal differentiation and allow pharmacological and toxicological evaluation of native GABAARs and GlyRs at different stages of brain maturation. We applied the cell line in concentration-response experiments with the neurotransmitters GABA and glycine as well as with the drugs strychnine, picrotoxin, fipronil, lindane, bicuculline, and zinc and demonstrate that the established in vitro model is applicable to GABAAR and GlyR-targeted pharmacological and toxicological profiling. We quantified the proportion of GABAAR and GlyR-sensitive cells, respectively, and identified percentages of approximately 20% each within the overall populations, rendering the cells a suitable model for systematic in vitro GABAAR and GlyR-targeted screening in the context of drug development and NT/DNT testing.

Optimizing neuronal differentiation of human pluripotent NT2 stem cells in monolayer cultures

“…The method has been repeatedly applied with recombinant NT2 cells stably expressing halide-sensitive YFP-I152L, allowing for functional characterization, for example, including GABA type-A receptors (GABAAR) and strychnine-sensitive glycine receptors (GlyR)ligand-gated chloride ion channels that mediate inhibitory neurotransmission in the central nervous system (CNS)demonstrating its suitability to successful differentiation of NT2 stem cells into neuronal NT2N cells (Kuenzel et al 2016). The method has been repeatedly applied with recombinant NT2 cells stably expressing halide-sensitive YFP-I152L, allowing for functional characterization, for example, including GABA type-A receptors (GABAAR) and strychnine-sensitive glycine receptors (GlyR)ligand-gated chloride ion channels that mediate inhibitory neurotransmission in the central nervous system (CNS)demonstrating its suitability to successful differentiation of NT2 stem cells into neuronal NT2N cells (Kuenzel et al 2016).…”

“…In this article, we describe an optimized methodology for differentiation of NT2 cells in monolayer cultures to address the issues encountered in the approaches reported in the literature. The method has been repeatedly applied with recombinant NT2 cells stably expressing halide-sensitive YFP-I152L, allowing for functional characterization, for example, including GABA type-A receptors (GABAAR) and strychnine-sensitive glycine receptors (GlyR)ligand-gated chloride ion channels that mediate inhibitory neurotransmission in the central nervous system (CNS)demonstrating its suitability to successful differentiation of NT2 stem cells into neuronal NT2N cells (Kuenzel et al 2016). We aimed to compare two almost similar protocols (Pleasure et al 1992;Stewart et al 2004) and one rather different approach (Saporta et al 2014) using: (i) expression of neuronal and non-neuronal markers, (ii) morphology of differentiated NT2-N cells, as well as (iii) the differentiation efficiency as quantifiers.…”

Nano- and Micro-Patterned S-, H-, and X-PDMS for Cell-Based Applications: Comparison of Wettability, Roughness, and Cell-Derived Parameters

“…A low number of cells, a small cellular area as well as a round cellular morphology typically indicate cell death. Healthy and viable cells are usually characterized by a comparatively higher cell number, larger cell area and an elongated morphology (Galluzzi et al, 2007 ; Wei et al, 2007 ; Barnhart et al, 2011 ; Gilbert et al, 2011 , 2016 ; Stanton et al, 2014 ; Dakhil et al, 2016 ; Gilbert and Boutros, 2016 ; Kuenzel et al, 2016 ; Schneidereit et al, 2016 ). Figures 4B–D show mean values (±SEM) of the cell number, the cell area and the mean elongation factor, respectively, for plane untreated (gray bars) and plasma treated (dark gray bars) PDMS.…”

“…We decided to use human foreskin fibroblasts as these cells are characterized by a strong, elongated morphotype, when maintained in monolayer cultures and also because fibroblasts have previously been applied for characterization of PDMS growth surfaces (van Kooten et al, 1998 ; Stanton et al, 2014 ). The cellular shape in in vitro cultures is an important estimator of cellular physiology and viability and can serve as an indicator of how strong a cell is attached to a growth substrate (Galluzzi et al, 2007 ; Barnhart et al, 2011 ; Dakhil et al, 2016 ; Kuenzel et al, 2016 ). For adherent cell lines, a round shape, unless during cell division, typically reflects altered cell fitness and/or adhesion to a growth substrate whereas an elongated morphology may indicate a healthy state and unaltered attachment to the culture surface (Stanton et al, 2014 ; Gilbert et al, 2016 ).…”

On the Generation of Efficient Methodologies for Cell-Based Toxicity Screening by Comparative Protocol Analysis and Optimization

“…NT2 stem cells exhibit many aspects of human embryonic neural stem cells [20]. Upon treatment with retinoic acid (RA), NT2 cells differentiate into post-mitotic cells, showing properties of cells of the central nervous system, also referred to as NT2-N cells [21][22][23][24][25][26]. These cells are committed towards neurons, astrocytes, and oligodendrocytes, which are the three main cell lineages of the CNS, and have extensively been used for drug in vitro screening and for studying human neurogenesis, brain regeneration, and terminal differentiation [20].…”