Transgenic inducible MHC I overexpression in mouse alveolar type 2 cells

Area of Science:

• Immunology
• Molecular Biology
• Respiratory Medicine

Background:

• Major histocompatibility complex class I (MHC I) is vital for adaptive immunity, presenting antigens to CD8+ T cells.
• MHC I expression varies across tissues; lung epithelial cells (LECs) have low basal levels, impacting susceptibility to infection and cancer.
• The role of MHC I overexpression in disease pathogenesis is poorly understood due to a lack of suitable in vivo models.

Purpose of the Study:

• To develop and characterize a novel mouse model for studying targeted MHC I upregulation in lung epithelial cells.
• To investigate the in vivo consequences of sustained MHC I overexpression in alveolar type 2 (AT2) cells.

Main Methods:

• Utilized a conditional Cre-lox system to specifically augment Nlrc5 expression in AT2 cells, leading to MHC I upregulation.
• Quantified MHC I surface expression levels and monitored for pathology and inflammation over time.
• Assessed the impact of sustained MHC I overexpression on respiratory disease initiation under steady-state conditions.

Main Results:

• Achieved a stable, tenfold increase in MHC I surface expression in AT2 cells, persisting for up to one year.
• Demonstrated that sustained MHC I overexpression did not induce pathology or inflammation in the absence of disease triggers.
• Indicated that MHC I overexpression does not initiate respiratory diseases under steady-state conditions.

Conclusions:

• The developed mouse model allows for the study of tissue-specific MHC I regulation and its role in disease.
• Sustained MHC I upregulation in lung epithelium is feasible without adverse effects, suggesting a potential therapeutic window.
• This model provides new avenues for investigating MHC I's role in respiratory diseases and developing targeted therapies.