Modelling prenatal stress in human neural progenitor cells

Abstract

Psychiatric disorders are a leading cause of disability, premature mortality, and economic burden globally, with a 48.1% increase in cases between 1990 and 2019. Stress in early life has been linked to hippocampal damage and the development of psychiatric disorders later in life. Personal stressors have also been found to be significantly associated with psychological distress, anxiety, and depression. Prenatal stress, which occurs when the fetus is exposed to excess glucocorticoids from maternal stress or synthetic glucocorticoids, has been linked to cognitive and behavioral outcomes later in life, possibly due to its impact on fetal development. In this project, I aimed to study the effect of cortisol on neural progenitor cells (NPCs) differentiated from human induced pluripotent stem cells (iPSCs). Cell type was confirmed using iPSC and NPC marker gene and protein expression by qPCR and immunofluorescence. The loss of undifferentiation marker SSEA4 in NPCs suggests that they are differentiated. The NPCs expressed SOX2, Nestin, SOX1, and PAX6, as confirmed by qPCR and immunofluorescence analyses. The percentage of SOX2, SOX1, PAX6, and Nestin positive cells was quantified based on colocalized signals with the nuclear marker DAPI. Novel Nestin isoforms that may be present in NPCs but not in iPSCs were identified. Currently, only one Nestin isoform is known to us. Novel, unpublished data from collaborators was used to confirm that there are Nestin isoforms present in fetal and adult human isoform sequencing study. Glucocorticoid (GC) response genes were upregulated after cortisol treatment in NPCs, as confirmed by qPCR. I measured NPC proliferation in response to cortisol and identified that cortisol did not significantly increase NPC proliferation. However, RNA sequencing showed differential expression of proliferation-related genes in cortisol-treated NPCs. RNA sequencing analysis revealed that 59 genes were differentially expressed in cortisol treated NPCs (including ZBTB16 and TSC22D3 measured previously using qPCR) compared to controls, out of which nine genes are associated with psychiatric traits based on GWAS studies. The study showed that cortisol can alter gene expression in NPCs, which may have implications for psychiatric disorders. Finally, the study emphasizes the novelty of exploring the role of cortisol in iPSC derived NPCs and highlights the need for further research in this area.