Guided self-organization and cortical plate formation in human brain organoids

Abstract

Three-dimensional cell culture models have either relied on the self-organizing properties of mammalian cells1-6 or used bioengineered constructs to arrange cells in an organ-like configuration7,8. While self-organizing organoids excel at recapitulating early developmental events, bioengineered constructs reproducibly generate desired tissue architectures. Here, we combine these two approaches to reproducibly generate human forebrain tissue while maintaining its self-organizing capacity. We use poly(lactide-co-glycolide) copolymer (PLGA) fiber microfilaments as a floating scaffold to generate elongated embryoid bodies. Microfilamentengineered cerebral organoids (enCORs) display enhanced neuroectoderm formation and improved cortical development. Furthermore, reconstitution of the basement membrane leads to characteristic cortical tissue architecture, including formation of a polarized cortical plate and radial units. Thus, enCORs model the distinctive radial organization of the cerebral cortex and allow for the study of neuronal migration. Our data demonstrate that combining 3D cell culture with bioengineering can increase reproducibility and improve tissue architecture.Correspondence should be addressed to M.A.L. mlancast@mrc

Generation of human brain region–specific organoids using a miniaturized spinning bioreactor

“…4e,f). A recent publication also reported a similar approach to reconstitute the basement membrane 36 . When allowed to grow beyond Day 100, the forebrain organoid gradually stops expanding in size.…”

Stem Cells, Genome Editing, and the Path to Translational Medicine

“…Exploiting the self-organizing capacity of neuroectodermal precursor cells, cerebral organoids recapitulate many features of human brain development and morphology, including ventricle and neural tube-like structures with apical-basal polarity, progenitor zone organization with outer radial glial stem cells, cortical plate development and electrophysiological mature neurons that participate in neuronal network activity (Kadoshima et al, 2013; Karzbrun et al, 2018; Lancaster et al, 2013; 2017; Li et al, 2017b; Paşca et al, 2015; Quadrato et al, 2017). Cerebral organoids have already provided novel insights into human-specific processes, which could not be studied in conventional 2D culture systems, such as brain gyrification (Karzbrun et al, 2018; Li et al, 2017b), cell migration and outer radial glial mitosis defects in Miller-Dieker syndrome (Bershteyn et al, 2017).…”

Translational potential of human brain organoids

“…Building on these earlier works, a recent flurry of papers described the generation of various neural organoids (Table 1), ranging from the whole‐brain organoids,27, 28, 29 to large sub‐brain regions such as cortical organoids,30, 31 to specific regions, including cerebellum,32 midbrain,33 adenohypophysis,34 hypothalamus,35 and hippocampus 36. Comparing with the classical neurospheres, these organoids are generally much larger.…”

“…In addition to the increased size, cerebral organoids showed highly thickened neuronal lobes within which neural progenitors and neurons reside. Immunostaining analysis revealed the presence of distinct zones such as the ventricular zone (VZ), the intermediate zone (IZ), and even the cortical plate‐like structure, similar to the developing brain 27, 29. Particularly exciting is the presence of so‐called outer subventricular zone (oSVZ), an embryonic structure that is uniquely expanded in humans but absent in rodents.…”

“…One possible way to establish a continuous morphogen gradient in the organoids is through the use of slow‐releasing microbeads 53. Bioengineered scaffolds with regulated signal release may represent another promising method to install external body axes and guide localized differentiation 29, 54. Second, regarding the variability of starting cells, a deeper understanding of stem cell biology may enable more precise control of the cells, thereby enhancing reproducibility.…”