Morphogenic, molecular, and cellular adaptations for unidirectional airflow in the chicken lung

Area of Science:

• Developmental Biology
• Comparative Anatomy
• Respiratory Physiology

Background:

• Avian lungs feature unidirectional airflow, contrasting with mammalian bidirectional flow.
• The developmental mechanisms behind avian lung structure and function remain largely unknown.
• Understanding avian lung development offers insights into respiratory system evolution.

Purpose of the Study:

• To delineate the morphogenic, molecular, and cellular processes of chicken lung development.
• To understand how these processes facilitate unidirectional airflow.
• To compare avian lung development with the mammalian model.

Main Methods:

• Multiscale 3D imaging of key developmental stages.
• Single-cell and spatial transcriptomics (Stereo-seq).
• Analysis of gene expression patterns (SOX9, SOX2, KRT14).

Main Results:

• Identified branch fusion processes forming parabronchi and radial alveologenesis.
• Described the SOX9-SOX2 transition in parabronchi development.
• Discovered a novel chicken-specific alveolar cell type (luminal cells expressing KRT14).
• Mapped vascular plexi to developing alveolar structures.
• Characterized the spatial organization of alveolar cell types.

Conclusions:

• Elucidated the developmental basis for unidirectional airflow in chicken lungs.
• Revealed a unique alveolar cell type contributing to avian lung function.
• Provides a foundation for studying evolutionary lung diversification and species-specific genetic factors.