Jiro Kawada

Generation of a Motor Nerve Organoid with Human Stem Cell-Derived Neurons

Summary During development, axons spontaneously assemble into a fascicle to form nerves and tracts in the nervous system as they extend within a spatially constrained path. However, understanding of the axonal fascicle has been hampered by lack of an in vitro model system. Here, we report generation of a nerve organoid composed of a robust fascicle of axons extended from a spheroid of human stem cell-derived motor neurons within our custom-designed microdevice. The device is equipped with a narrow channel providing a microenvironment that facilitates the growing axons to spontaneously assemble into a unidirectional fascicle. The fascicle was specifically made with axons. We found that it was electrically active and elastic and could serve as a model to evaluate degeneration of axons in vitro. This nerve organoid model should facilitate future studies on the development of the axonal fascicle and drug screening for diseases affecting axon fascicles.

Compartmentalized embryoid body culture for induction of spatially patterned differentiation

We developed a compartmentalized culture system of single embryoid bodies (EBs) utilizing a through-hole on a membrane to induce spatially patterned differentiation. An EB derived from mouse pluripotent stem cells was immobilized on the through-hole. By introducing a stem cell maintenance medium and a differentiation medium into upper and lower culture compartments, respectively, a localized differentiated state was achieved only in the lower part of EB, which is exposed to the medium in the lower compartment. This system may enable us to reconstruct complex tissues and to recapitulate developmental processes using EBs.

Microfluidic Approach to Cell Handling and Measurement

Microfluidic technologies enable us to analyze cells with much higher resolution in space and time. The approaches are mostly realized by making use of numerous advantageous features of microfluidic systems, such as relatively small dimensions, low Reynolds number flow, etc. In this chapter, the examples of microfluidic approach to cell handling and measurement highlighting its advantageous features will be described. It will be shown that the microfluidic approach is among the promising methods for the future experimentation in biomedical applications.