Transcriptional and cellular response of hiPSC-derived microglia-neural progenitor co-cultures exposed to IL-6.

Couch ACM., Brown AM., Raimundo C., Solomon S., Taylor M., Sichlinger L., Matuleviciute R., Srivastava DP., Vernon AC.

Elevated interleukin (IL-)6 levels during prenatal development have been linked to increased risk for neurodevelopmental disorders (NDD) in the offspring, but the mechanism remains unclear. Human-induced pluripotent stem cell (hiPSC) models offer a valuable tool to study the effects of IL-6 on features relevant for human neurodevelopment in vitro. We previously reported that hiPSC-derived microglia-like cells (MGLs) respond to IL-6, but neural progenitor cells (NPCs) in monoculture do not. Therefore, we investigated whether co-culturing hiPSC-derived MGLs with NPCs would trigger a cellular response to IL-6 stimulation via secreted factors from the MGLs. Using N=4 donor lines without psychiatric diagnosis, we first confirmed that NPCs can respond to IL-6 through trans-signalling when recombinant IL-6Ra is present, and that this response is dose-dependent. MGLs secreted soluble IL-6R, but at lower levels than found in vivo and below that needed to activate trans-signalling in NPCs. Whilst transcriptomic and secretome analysis confirmed that MGLs undergo substantial transcriptomic changes after IL-6 exposure and subsequently secrete a cytokine milieu, NPCs in co-culture with MGLs exhibited a minimal transcriptional response. Furthermore, there were no significant cell fate-acquisition changes when differentiated into post-mitotic cultures, nor alterations in synaptic densities in mature neurons. These findings highlight the need to investigate if trans-IL-6 signalling to NPCs is a relevant disease mechanism linking prenatal IL-6 exposure to increased risk for psychiatric disorders. Moreover, our findings underscore the importance of establishing more complex in vitro human models with diverse cell types, which may show cell-specific responses to microglia-released cytokines to fully understand how IL-6 exposure may influence human neurodevelopment.

DOI

10.1016/j.bbi.2024.08.007

Type

Journal article

Publication Date

2024-11-01T00:00:00+00:00

Volume

122

Pages

27 - 43

Total pages

16

Addresses

Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, UK; MRC Centre for Neurodevelopmental Disorders, King's College London, London, UK. Electronic address: amalie.c.couch@kcl.ac.uk.

Keywords

Microglia, Cells, Cultured, Humans, Receptors, Interleukin-6, Interleukin-6, Cytokines, Coculture Techniques, Signal Transduction, Cell Differentiation, Induced Pluripotent Stem Cells, Neural Stem Cells, Transcriptome

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