A controllable human spinal cord model with full dorsoventral patterning

Dorsoventral (DV) patterning of the spinal cord (SC) is orchestrated by morphogen gradients that specify distinct neural progenitor domains, the dorsal roof plate (RP), ventral floor plate (FP), and delaminating neural crest cells (NCCs). While foundational insights into SC patterning have been gained from animal models, key aspects - such as the role of retinoic acid (RA), dynamics of NCC lineage development, and human-specific features - remain poorly understood due to limitations in existing in vivo and in vitro models. Here, we present a human pluripotent stem cell (hPSC)-derived SC model, termed microfluidic SC-like structures (µSCLSs), generated by applying bioengineered, antiparallel morphogen gradients via a microfluidic platform over micropatterned hPSC colonies. The µSCLS robustly recapitulates complete DV patterning with human specific transcriptional signatures. Using this platform, we uncover a previously unrecognized RA-BMP signaling crosstalk that could explain conflicting reports on the role of RA in SC DV patterning. We further demonstrate lineage-specific ventral migration of NCCs in response to chemoattractant cues, enabling direct visualization and mechanistic dissection of sensory vs. other fate trajectories. This controllable, reproducible, and human-relevant model provides a powerful system for probing human SC development, neural crest biology, and disease modeling with unprecedented resolution.