FGFR and PTEN signaling interact during lens development to regulate cell survival

Area of Science:

• Ophthalmology
• Cell Biology
• Developmental Biology

Background:

• Lens epithelial cells utilize receptor tyrosine kinases (RTKs) to activate intracellular signaling pathways, including PI3K-AKT and RAS-RAF-MEK-ERK.
• These pathways regulate critical cellular processes like proliferation, survival, metabolism, and differentiation.
• Fibroblast growth factor receptors (FGFRs) are the only RTKs in the lens known to induce lens epithelial cell to fiber cell differentiation in mammals.

Purpose of the Study:

• To investigate the roles of FGFR2 and PTEN in lens development and differentiation.
• To determine if combined deletion of FGFR2 and PTEN can rescue cell death and restore differentiation.
• To explore the impact of PTEN on AKT and ERK activation in the lens.

Main Methods:

• Genetic manipulation in mice to achieve conditional deletion of Fgfr2 and Pten genes at specific developmental stages (lens placode).
• Analysis of lens cell survival, proliferation, and differentiation markers (e.g., Aquaporin0, DnaseIIβ).
• Assessment of intracellular signaling pathway activation (AKT, ERK) through molecular assays.

Main Results:

• Combined deletion of Fgfr2 and Pten rescued the cell death observed in Fgfr2-deficient lenses.
• Pten deletion alone or in combination with Fgfr2 deletion increased AKT and ERK activation.
• Neither isolated Pten deletion nor combined Fgfr2 and Pten deletion restored differentiation-specific gene expression (Aquaporin0, DnaseIIβ) in lens fiber cells.

Conclusions:

• FGFR2 is essential for lens cell survival and proper fiber cell differentiation.
• While PTEN loss can rescue cell death, it is insufficient to induce or restore lens fiber cell differentiation.
• Modulating these pathways offers insights into lens development but highlights the complexity of differentiation signaling.