BIOENGINEERING THE NICHE: A BIOMIMETIC APPROACH TO MODEL HUMAN OLIGODENDROCYTE PHYSIOLOGY AND MYELINATION <EM>EX VIVO</EM>

Oligodendrocytes (OLs) are pivotal for central nervous system (CNS) homeostasis and axonal myelination. However, elucidating human myelination dynamics is hindered by tissue inaccessibility and interspecies differences. Differentiating OLs from human induced pluripotent stem cells (hiPSCs) offers a solution, particularly when coupled with biomaterials that mimic the CNS microenvironment. These bioengineered scaffolds provide essential biophysical cues—mimicking native stiffness and topography—that are crucial for enhancing OL maturation and establishing robust, quantifiable models of human myelination.
In this study, KiPS3F-7 cell line was differentiated into OLs over 150 days. Pre-mature OLs were FACS-isolated and transduced using a lentivirus containing a mCherry-tagged plasmid. These OLs were evaluated using three approaches: 1) co-culture with neural stem cell (NSC)-derived neurons; 2) seeding on PDMS-derived nanopillars with distinct configurations; and 3) seeding carbon-based scaffolds to study OL wrapping abilities. Live-cell imaging was performed to assess OL dynamics.
Differentiation yielded high-purity cultures, though conditioned media was crucial to mitigate post-isolation apoptosis. While OLs formed clusters in standard neuron-OL co-cultures, PDMS nanotopographies induced neuronal alignment, prompting OLs to reorganize and align unidirectionally without clustering. Furthermore, carbon scaffolds demonstrated the intrinsic capacity of OLs to migrate along them and ensheathe up to three different synthetic fibers in a close distance.
In conclusion, combining hiPSC-derived OLs with functionalized biomaterials effectively recapitulates complex physiological behavior, such as alignment and wrapping, providing a robust, physiologically relevant platform to decipher human myelination mechanics ex vivo. Ultimately, unraveling these specific mechanisms is essential to pave the way for novel therapeutic strategies.