Stereotyped Subclones Revealed by High-Density Single-Cell Lineage Tracing Support Robust Development

Area of Science:

• Developmental Biology
• Stem Cell Biology
• Tissue Engineering

Background:

• Multicellular organism development relies on robustness, yet intercellular and tissue-level mechanisms remain poorly understood.
• Existing research primarily focuses on subcellular mechanisms, leaving a gap in understanding higher-level robustness.
• Directed differentiation models offer a platform to study in vitro recapitulation of in vivo developmental processes.

Purpose of the Study:

• To investigate intercellular and tissue-level mechanisms contributing to developmental robustness.
• To analyze cell lineage trees (CLTs) and single-cell transcriptomes during human lung progenitor cell differentiation.
• To identify novel bases for developmental robustness beyond transcriptional memory.

Main Methods:

• Utilized an in vitro directed differentiation model of human embryonic stem cells into lung progenitor cells.
• Integrated high-density cell lineage trees (CLTs) with single-cell transcriptomic data.
• Analyzed differentiating colonies to resolve cell types and developmental hierarchies.

Main Results:

• Found little evidence for transcriptional memory contributing to developmental robustness.
• Observed stable terminal cell type compositions in subclones, enhancing robustness against cell death.
• Identified stereotyped sub-CLTs with similar terminal cell compositions and topological structures as a novel basis for robustness.

Conclusions:

• Stereotyped sub-CLTs represent a new mechanism for developmental robustness at the intercellular level.
• This finding suggests a paradigm shift from solely focusing on individual cell properties to understanding collective organization.
• Results provide a framework connecting cell-type atlases with the organization of functional tissues.