Characterization of novel mouse models to study the role of necroptosis in aging and age-related diseases

AbstractTo study the impact of necroptosis-induced chronic inflammation on age-related diseases and aging, two knockin mouse models (Ripk3-KI andMlkl-KI) were generated that overexpress two genes involved in necroptosis (Ripk3 orMlkl) when crossed to Cre transgenic mice. CrossingRipk3-KI orMlkl-KI mice to albumin-Cre transgenic mice produced hepatocyte specifichRipk3-KI orhMlkl-KI mice, which express the two transgenes only in the liver. Ripk3 and Mlkl proteins were overexpressed 10- and fourfold, respectively, in the livers of thehRipk3-KI orhMlkl-KI mice. Treating young (2-month)hRipk3-KI orhMlkl-KI mice with carbon tetrachloride (CCl4), a chemical inducer of oxidative stress, resulted in increased necroptosis (Mlkl-oligomers) and inflammation in the liver compared to control mice receiving CCl4. Mlkl-oligomerization also was significantly increased in old (18-month)hRipk3-KI andhMlkl-KI mice compared to old control (Cre negative,Ripk3-KI andMlkl-KI) mice. The increase in necroptosis was associated with an increase in inflammation, e.g., inflammatory cytokines (TNF α, IL-6) and macrophage markers (F4/80, CD68). Importantly, steatosis (triglycerides) and fibrosis (e.g., picrosirius red staining, hydroxyproline levels, and transcripts for TGFβ, Col1α1, and Col3α1) that increase with age were significantly higher in the livers of the oldhRipk3-KI orhMlkl-KI mice compared to old control mice. In addition, markers of cellular senescence were significantly increased in the li...
Source: AGE - Category: Geriatrics Source Type: research