Neonatal hepatitis induced by alpha 1-antitrypsin: a transgenic mouse model

Area of Science:

• Genetics
• Molecular Biology
• Pathology

Background:

• Alpha 1-antitrypsin (alpha 1-Pi) deficiency is a genetic disorder.
• Understanding the role of different alpha 1-Pi alleles is crucial for disease modeling.

Purpose of the Study:

• To create and characterize transgenic mouse models for human alpha 1-antitrypsin (alpha 1-Pi) gene alleles.
• To investigate the in vivo expression and cellular accumulation of normal (M) and mutant (Z) human alpha 1-Pi proteins.

Main Methods:

• Generation of transgenic mouse lineages carrying human alpha 1-Pi M and Z alleles.
• Analysis of human alpha 1-Pi protein expression in various tissues and serum.
• Histopathological examination of liver tissue, including Periodic acid-Schiff (PAS) staining.

Main Results:

• Transgenic mice expressed human alpha 1-Pi protein in multiple organs, including liver, cartilage, gut, kidneys, lymphoid macrophages, and thymus.
• Normal M-allele protein secreted efficiently into serum; mutant Z-allele protein accumulated intracellularly, especially in hepatocytes, with lower serum levels.
• Mice with high Z-allele expression exhibited neonatal runting and alpha 1-Pi-induced liver pathology, characterized by protein accumulation in cytoplasmic globules.

Conclusions:

• Transgenic mice expressing human alpha 1-Pi alleles provide a valuable tool for studying alpha 1-Pi-related diseases.
• The Z-allele transgenic mouse model mimics key aspects of human neonatal hepatitis, offering a platform for therapeutic research.