Genetics of life span in mice

Area of Science:

• Immunology
• Genetics
• Gerontology

Background:

• Early thymic involution is linked to genetic and environmental interactions, potentially causing immune dysregulation.
• Immune defects are associated with increased susceptibility to autoimmune diseases, malignancy, and age-related infections.
• The major histocompatibility complex (MHC) may influence lifespan and cause of death profiles.

Purpose of the Study:

• To investigate the influence of the MHC (specifically H-2) on lifespan using various experimental protocols.
• To understand how genetic background and environmental factors, such as viral infections, modify the genetic control of lifespan.

Main Methods:

• Utilized multiple genetic models, including backcross and intercross mice with different H-2 genotypes (H-2d, H-2b) in B10 congenic strains.
• Compared lifespan data between male and female mice.
• Assessed the impact of Sendai virus infection on lifespan across different genetic backgrounds and MHC genotypes.

Main Results:

• Interactions between genetic regions influencing lifespan were inconsistent, especially when comparing infected and uninfected mice.
• The MHC (H-2) served as a marker for lifespan in specific male mouse models.
• Sex-specific lifespan differences were observed across different genetic backgrounds; females lived longer in backcross/intercross, males in B10 congenics.
• H-2d genotype showed a disadvantage in lifespan under specific conditions (Sendai infection in certain males), while H-2b showed a disadvantage when infected.
• Environmental factors like Sendai virus infection altered the lifespan advantage/disadvantage associated with specific MHC genotypes.

Conclusions:

• Lifespan is influenced by complex genetic interactions, including locus and allelic interactions, which can be modified by environmental exposures.
• The MHC's role in lifespan is context-dependent, varying with genetic background and environmental conditions.
• Studying lifespan genetics requires diverse genetic models and careful monitoring of infections and environmental factors.