ESRP1-Associated CD44 Alternative Splicing Stratifies Epithelial-Mesenchymal Identity States in a Non-Transformed...

Area of Science:

• Cell Biology
• Developmental Biology
• Molecular Biology

Background:

• Epithelial-mesenchymal plasticity (EMP) allows cells to adapt to biological changes.
• While EMP is studied in cancer, its role in normal physiological states is less understood.
• CD44 splicing and epithelial splicing regulators (ESRP1/2) are key in cancer-associated EMT.

Purpose of the Study:

• To define distinct epithelial, intermediate, and mesenchymal identity states in a non-malignant human cellular system.
• To investigate CD44 isoform usage and ESRP1 expression across these physiological identity states.
• To establish a tractable model for studying EMP beyond cancer.

Main Methods:

• Utilized primary dermal fibroblasts, induced pluripotent stem (iPS) cells, and iPS-derived mesenchymal stem cells (iPS-MSCs).
• Employed morphological assessment, lineage marker profiling, and RT-qPCR analyses.
• Investigated CD44 expression/splicing and ESRP1 expression/silencing effects.

Main Results:

• Reproducible stratification of epithelial, intermediate, and mesenchymal states was observed.
• CD44 expression and splicing varied across states, with CD44s in fibroblasts and variant exon inclusion in iPS cells.
• ESRP1 expression correlated with CD44 splicing; ESRP1 silencing shifted splicing towards CD44s.

Conclusions:

• A non-transformed human model capturing key molecular features of EMP was established.
• CD44 splicing and ESRP1 play roles in physiological cell identity states.
• This model facilitates studying EMP in non-malignant contexts.