Abstract

Promoting central nervous system (CNS) -related cell replacement, including neurons and glial cells differentiated from endogenous neural progenitor cells (NPCs) using biomaterials, becomes an invaluable approach to aid the development of potential therapeutic interventions for neurological disorders and injuries [1]. Here, we explored the multifaceted strategies that harness the 3D extrusion bioprinting of NPCs derived from human induced pluripotent stem cells (hiPSCs) to facilitate their integration and spontaneous differentiation capacity in response to the shear-thinning Gelatin Methacryloyl (GelMA)/ Pluronic F127 (P-127) composite bioinks. As a result, P-127 provided an extra physical gelation of GelMA-based bioink that benefits printability, high swelling ratios, slow degradation, and optimal controlling pore size for cell proliferation. The Young's modulus obtained in our study was within 1 – 15 kPa, with the GelMA/P-127 reaching a higher value than the GelMA alone. The immunostaining study demonstrated that the increased GFAP expression coincided with decreased Neurofilament M expression; it suggests that regulating mechanical properties by altering P-127 concentration in GelMA shifts preferential differentiation into astrocytes over neurons. The gene expression studies on days 14 and 28 confirmed the differentiation of iPSC-NPCs through upregulating GFAP, TUBB3, MAP2, and downregulating SOX2. As a proof of concept, the co-culture of 3D bioprinted constructs demonstrated integration with ex vivo mouse brain slices and exhibited TUBB3 as a neuronal marker. Our findings reveal that the GelMA/P-127 composite bioinks exhibit favorable properties for generating bioprinted constructs to sustain the extended proliferation of hiPSC-NPCs and promote their differentiation into neurons and astrocytes. This capability facilitates the development of intricate 3D neural tissue-like structures, establishing a robust platform for screening novel therapeutics and evaluating their potential impact on CNS regenerative medicine.
Keywords: neural progenitor cells (NPC), neural differentiation, Gelatin Methacryloyl (GelMA), 3D bioprinting.

Reference: [1] C.-G. Song, Y.-Z. Zhang, H.-N. Wu, X.-L. Cao, C.-J. Guo, Y.-Q. Li, M.-H. Zheng, H. Han, Stem cells: a promising candidate to treat neurological disorders, Neural regeneration research, 13 (2018) 1294.