Humanized L184Q Mutated Surfactant Protein C Gene Alters Alveolar Type 2 Epithelial Cell Fate

Area of Science:

• Pulmonary Biology
• Cell Biology
• Genetics

Background:

• Alveolar type 2 (AT2) cells are crucial for lung repair and surfactant protein C (SPC) synthesis.
• Mutations in the surfactant protein C gene (Sftpc) are linked to neonatal respiratory distress and pulmonary fibrosis.
• The precise mechanisms by which Sftpc mutations impact AT2 cell lineage remain largely unknown.

Purpose of the Study:

• To investigate the intrinsic effects of the humanized Sftpc L184Q mutation on AT2 cell lineage.
• To compare AT2 cell characteristics between wild-type (WT) and Sftpc L184Q mutant mice using in vitro organoid models.

Main Methods:

• Utilized three-dimensional (3D) feeder-free AT2 organoids derived from WT and Sftpc L184Q mutant mice.
• Performed colony formation assays, immunofluorescence, flow cytometry, qRT-PCR, and Western blot analysis.
• Assessed AT2 cell numbers, organoid formation, colony-forming efficiency, and marker expression (e.g., PDPN).

Main Results:

• Sftpc L184Q mutant mice exhibited significantly reduced AT2 cell numbers.
• Primary Sftpc L184Q AT2 cells showed attenuated organoid formation and colony-forming efficiency compared to WT.
• Increased Podoplanin (PDPN) expression, an Alveolar type 1 cell marker, was observed in Sftpc L184Q organoids.
• Expression of CD74, HSP90, and RPS3A1 was not significantly different between mutant and WT AT2 cells.

Conclusions:

• The humanized Sftpc L184Q mutation intrinsically regulates AT2 cell lineage.
• This regulation impacts AT2 cell proliferation, differentiation, and regenerative capacity.
• The observed effects are independent of the CD74, HSP90, and RPS3A1 pathways.