Microstructured Hydrogels to Guide Self-Assembly and Function of Lung Alveolospheres

Area of Science:

• Stem Cell Biology
• Tissue Engineering
• Regenerative Medicine

Background:

• Epithelial organoids are valuable tools for studying tissue development, disease, and cell transplantation.
• Current organoid culture methods predominantly use 3D Matrigel, leading to undefined conditions, animal components, and heterogeneous organoids.
• Heterogeneity in organoid size, shape, and composition limits their utility in research and therapeutic applications.

Purpose of the Study:

• To develop a Matrigel-free method for generating and expanding lung alveolar organoids (alveolospheres).
• To utilize defined hyaluronic acid hydrogels for controlled organoid formation.
• To reduce heterogeneity in organoid size and structure compared to traditional 3D culture methods.

Main Methods:

• Human-induced pluripotent stem cell (iPSC)-derived alveolar type 2 cells (iAT2s) were cultured in synthetic hyaluronic acid hydrogels.
• Defined chemical and physical properties of the hydrogels were engineered to promote self-assembly.
• Predefined microcavities were incorporated into the hydrogels to guide alveolosphere formation and reduce heterogeneity.

Main Results:

• iAT2s self-assembled into alveolospheres and propagated effectively in Matrigel-free hyaluronic acid hydrogels.
• Engineered microcavities significantly reduced the heterogeneity of alveolosphere size and structure.
• The alveolar type 2 cell fate of iPSC-derived progenitor cells was maintained within the hydrogel-cultured alveolospheres.

Conclusions:

• Hyaluronic acid hydrogels provide a facile and accessible system for culturing iPSC-derived lung progenitors.
• This method enables the generation of more uniform alveolospheres, overcoming limitations of Matrigel-based cultures.
• The hydrogel system is adaptable for culturing primary mouse alveolar type 2 cells and other epithelial progenitor aggregates.