Distinct Vulnerability and Resilience of Human Neuroprogenitor Subtypes in Cerebral Organoid Model of Prenatal Hypoxic Injury.

Nicolas Daviaud,Roland H Friedel,Clément Chevalier,Hongyan Zou

doi:10.3389/fncel.2019.00336

Abstract

Prenatal hypoxic injury (HI) is a leading cause of neurological disability. The immediate and long-term effects of hypoxia on progenitor homeostasis and developmental progression during early human brain development remain unclear. This gap is due to difficulty to access human fetal brain tissues and inadequate animal models to study human corticogenesis. Recent optimizations of cerebral organoid models derived from human embryonic stem (ES) cells present new opportunities to investigate pathophysiology of prenatal HI. Here, we implemented a transient HI model using human cerebral organoids with dorsal forebrain specification. We demonstrated that transient hypoxia resulted in immediate and prolonged apoptosis in cerebral organoids, with outer radial glia (oRG), a progenitor population more prominent in primates, and differentiating neuroblasts/immature neurons suffering larger losses. In contrast, neural stem cells in ventricular zone displayed relative resilience to HI and exhibited a shift of cleavage plane angle favoring symmetric division, thereby providing a mechanism to replenish the stem cell pool. Furthermore, we defined the vulnerable window and neurodifferentiation stages that are particularly sensitive to HI. Understanding cell type-specific and stage-dependent effects of prenatal HI on survival and mitotic behavior of human neuroprogenitor subtypes during early human corticogenesis helps elucidate the etiology of neurodevelopmental disorders, and provides a therapeutic starting point to protect the vulnerable populations at critical timeframes.

Highlights

Prenatal hypoxic injury (HI) is a leading cause of neurological disability, with an incidence of 2–4 per 1000 live births (Badr Zahr and Purdy, 2006; Glass and Ferriero, 2007)
Human cerebral organoids contain a progenitor domain that is more prominent in primates, termed outer subventricular zone (SVZ), which is populated by outer radial glia, which support the evolutionary expansion of human neocortex (Hansen et al, 2010; Dehay et al, 2015; Pollen et al, 2015)
From D21 to D42, a majority of Ki67+ cells remained in the ventricular zone (VZ), while a small fraction of Ki67+ cells appeared in outer layers representing intermediate progenitors expressing TBR2 (EOMES) and neuroblasts expressing DCX (Hevner et al, 2006; Figure 1B and Supplementary Figure S1B)

Summary

Introduction

Prenatal hypoxic injury (HI) is a leading cause of neurological disability, with an incidence of 2–4 per 1000 live births (Badr Zahr and Purdy, 2006; Glass and Ferriero, 2007). The immediate and long-term effects of hypoxia on NPC homeostasis and differentiation trajectory during early human brain development remain poorly understood, and this is due to relative inaccessibility of human fetal brain tissues and inadequate animal models to study human corticogenesis. Recent advances in 3D cerebral organoid cultures derived from human embryonic stem cells (hESC) or induced pluripotent stem cells (iPSC) (Kadoshima et al, 2013; Lancaster et al, 2013; Lancaster and Knoblich, 2014; Camp et al, 2015) provide new avenues to implement reproducible models to study cell type- and stage-specific effects of HI on early human cortical development. Cerebral organoid cultures take advantage of the enormous self-organizing potential of neural stem cells (NSCs) and differentiating NPCs to develop into complex structures that mimic early to mid-gestation human brain development (Camp et al, 2015). Human cerebral organoids contain a progenitor domain that is more prominent in primates, termed outer SVZ (oSVZ), which is populated by outer radial glia (oRG), which support the evolutionary expansion of human neocortex (Hansen et al, 2010; Dehay et al, 2015; Pollen et al, 2015)

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Results

Conclusion