Gene expression profiling in an induced pluripotent stem cell model of the developing human telencephalon: effect of heat shock and its potential impact on the development of neuropsychiatric disorders

Schizophrenia (SZ) and autism spectrum disorders (ASD) are highly heritable neuropsychiatric/neurodevelopmental disorders, although environmental factors, such as maternal immune activation (MIA), play a role as well. Inflammatory cytokines appear to mediate the effects of MIA on neurogenesis and behavior in animal models. However, drugs and cytokines that trigger MIA can also induce a febrile reaction, which could have independent effects on neurogenesis through heat shock (HS)-regulated cellular stress pathways. However, this has not been well-studied. As a first step towards addressing the role of fever in MIA, we used a recently described model of human brain development in which induced pluripotent stem cells (iPSCs) differentiate into 3-dimensional neuronal aggregates that resemble a first trimester telencephalon. RNA-seq was carried out on aggregates that were heat shocked at 39oC for 24 hours, along with their control partners maintained at 37oC. Overall, 186 genes showed significant differences in expression following HS (p<0.05), including known HS-inducible genes, as expected, as well as those coding for NGFR and a number of SZ and ASD candidates, including SMARCA2, DPP10, ARNT2, AHI1 and ZNF804A. The degree to which the expression of these genes decrease or increase during HS is similar to that found in copy loss and copy gain CNVs, although the effects of HS are likely to be more transient. Overall design: RNA-seq was carried out on neuronal aggregates as described by Mariani et al. with slight modification (PMID:22761314). For the heat shock experiment, a group of 49 day old aggregates was placed in an incubator set at 39C for 24 hours, while control sets of aggregates were maintained at 37C. The incubator conditions were otherwise unchanged. After detaching the aggregates, total cellular RNA was isolated using the miRNeasy Kit (Qiagen) according to the manufacturer's protocol. Lastly, RNAseq profiles of HS and Control were compared

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Lin M, Zhao D, Hrabovsky A, Pedrosa E, Zheng D, Lachman HM