Project Summary Modeling NDE1 function in dysregulated brain development using a microfluidic CNS model Development of the vertebrate central nervous system (CNS) begins with the formation of neural tube (NT) and its regional patterning to generate the forebrain, midbrain, hindbrain, and spinal cord. Regional patterning of the brain is a tightly regulated developmental process, deviation from which can result in neurodevelopmental brain diseases. Multiple causes are associated with neurodevelopmental brain diseases, including genetic, environmental, infectious, and traumatic factors. Even though the precise etiology of neurodevelopmental brain diseases remains largely unknown, the genetic components of neurodevelopmental brain diseases have been increasingly deciphered with the advent of personalized medicine. However, detailed pathophysiological mechanisms of neurodevelopmental brain diseases remain challenging to study, due to limited access to human CNS tissues. Animal models have been instrumental in understanding human neurodevelopment and associated disorders. However, they are limited in revealing some of the most fundamental aspects of development, genetics, pathology, and disease mechanisms that are unique to humans. Stem cell-based in vitro models of human neurodevelopment are emerging as promising experimental tools. However, the controllability and reproducibility of these models remain suboptimal. Furthermore, none of the current neurodevelopment models is capable of recapitulating regional patterning of the brain faithfully in a 3D tubular geometry, a hallmark of neurodevelopment. The goal of this R21 project is to specifically address this significant technological need, by using human pluripotent stem cells (hPSCs) to develop a human brain development model that can faithfully recapitulate regional brain patterning. Importantly, we propose to apply this model to study the function of nuclear distribution element 1 (NDE1), a gene implicated in a wide range of neurodevelopmental conditions, including microcephaly (a small brain), microlissencephaly (a small brain with a simplified gyral pattern), or microhydranencephaly (a more severe presentation). In our preliminary study, we have successfully leveraged the developmental potential and self-organizing property of hPSCs in conjunction with innovative microfluidics to develop the first of its kind, synthetic, fully patterned human NT model. Our preliminary data from brain organoids generated from NDE1-knockout (KO) hPSCs further show that NDE1-KO brain organoids exhibit reduced growth and gyrification and furthermore show abnormal brain regionalization. Thus, our preliminary data suggest a novel and previously unexplored mechanism involving dysregulated brain regionalization in NDE1-mediated microcephaly. In this proposal, we propose to first extend the microfluidic patterned human NT model to recapitulate brain regionalization (Aim 1). We will then utilize this controllable human b...