Engineering human cell spheroids to model embryonic tissue fusion in vitro

Area of Science:

• Developmental Biology
• Regenerative Medicine
• Toxicology

Background:

• Epithelial-mesenchymal interactions are vital for embryonic development, with disruptions leading to birth defects like cleft palate.
• Current understanding of chemical exposure effects on human embryonic fusion is limited due to a lack of suitable in vitro models.
• Cleft palate's prevalence and the embryonic palate's structure make it an ideal system for studying developmental fusion.

Purpose of the Study:

• To develop a novel 3D in vitro culture system that accurately mimics embryonic palate fusion using human cells.
• To establish a robust model for investigating the impact of chemical exposures on human developmental fusion processes.
• To provide a platform for predictive toxicology relevant to birth defect research.

Main Methods:

• Engineered size-controlled human Wharton's Jelly stromal cell (HWJSC) spheroids.
• Cultured HWJSC spheroids in osteogenesis differentiation medium for 7 days to induce an osteogenic phenotype.
• Co-cultured HWJSC spheroids with human epidermal progenitor cells (HPEKp) and analyzed fusion behavior.

Main Results:

• HWJSC spheroids successfully supported HPEKp attachment, mimicking embryonic palatal mesenchyme and epithelium.
• Engineered spheroids exhibited in vitro fusion behavior, characterized by epithelial cell removal at spheroid seams.
• Fusion was dependent on epidermal growth factor and fibroblast growth factor signaling, consistent with known palate development pathways.

Conclusions:

• A novel 3D human cell culture system effectively models embryonic palate fusion in vitro.
• This system provides a valuable tool for studying epithelial-mesenchymal interactions during development and their disruption.
• The model holds potential for predictive toxicology, assessing chemical impacts on human developmental fusion events.