A Patterned Human Neural Tube Model Using Microfluidic Gradients.

Human nervous system is arguably the most complex but highly organized organ. Foundation of its complexity and organization is laid down during regional patterning of neural tube (NT), the embryonic precursor to human nervous system. Historically, studies of NT patterning have relied on animal models to uncover underlying principles. Recently, human pluripotent stem cell (hPSC)-based models of neurodevelopment, including neural organoids1-5 and bioengineered NT development models6-10, are emerging. However, existing hPSC-based models fail to recapitulate neural patterning along both rostral-caudal (R-C) and dorsal-ventral (D-V) axes in a three-dimensional (3D) tubular geometry, a hallmark of NT development. Herein we report a hPSC-based, microfluidic NT-like structure (or μNTLS), whose development recapitulates some critical aspects of neural patterning in both brain and spinal cord (SC) regions and along both R-C and D-V axes. The μNTLS was utilized for studying neuronal lineage development, revealing prepatterning of axial identities of neural crest (NC) progenitors and functional roles of neuromesodermal progenitors (NMPs) and caudal gene CDX2 in SC and trunk NC development. We further developed D-V patterned, microfluidic forebrain-like structures (μFBLS) with spatially segregated dorsal and ventral regions and layered apicobasal cellular organizations that mimic human forebrain pallium and subpallium developments, respectively. Together, both μNTLS and μFBLS offer 3D lumenal tissue architectures with an in vivo-like spatiotemporal cell differentiation and organization, promising for studying human neurodevelopment and disease.