9285 Development of an androgen receptor transgenic mouse that displays the complete attributes of Metabolic Syndrome
Authors: Alvarado Carlos , Beitel Lenore K , Paliouras Miltiadis , Trifiro Mark Anthony 
Published: October 2024

Disclosure: C. Alvarado: None. L.K. Beitel: None. M. Paliouras: None. M.A. Trifiro: None.

The mouse androgen receptor (AR) shares over 90% homology with the human ortholog, but it lacks the CAG encoded poly-Q tract; instead, it contains a mixed glutamine/histidine tract. To study AR functionality in a more structured fashion, we created a knock-in mouse model that has only the equivalent of human poly-Q tract while maintaining the remaining mouse receptor sequence intact. Our humanized androgen receptor mouse (AR-19Q) displays a phenotype that is best described as Metabolic Syndrome (MetS). The mice gain excess weight, have hypertension, hyperglycemia, pancreatic islet cell abnormalities, and progressive non-alcoholic fatty liver disease (NAFLD). Features of MetS begin at approximately 4 months and progress till 12-14 months. Obesity: AR-19Q mice are significantly heavier, with a 35% gain of weight vs C57BL/6 mice. However, these mice are not hyperphagic at any time and eat identical quantities of chow. To assess obesity status, and found AR-19Q mice to have a significantly higher depositions of total white adipose visceral, lingual and subcutaneous vs age-matched controls. NAFLD: The progression of NAFLD is observed in AR-19Q mice. AR-19Q Histological analysis and immunohistochemistry reveal microvesicular steatosis, superseded by macrovesicular steatosis with hepatocyte balloon degeneration, scattered lobular inflammation (macrophages and lymphocytes) (6-9 months) and further superseded by perisinusoidal fibrosis (12 months). Biochemical blood analysis confirms. that there is a significant increase in alanine aminotransferase (ALT) levels, indicative of liver damage. With time classical NASH hepatitis and subsequent NASH fibrosis ensues; with several mice developing hepatocellular carcinoma (overall 20% of mice). Gene expression profiling AR-19Q mice for fatty liver genes, we observe an upregulation of inflammation genes Il-6, Il-10 and Tnf. In addition, increased Lpl (lipoprotein lipase) is indicative of increased blood triglyceride levels. On the other hand, down-regulation of G6pc (glucose-6-phosphatase) could be linked to glycogen storage disease. Down-regulation of Slc2a2 and Slc2a4, that encode GLUT2 and GLUT4, should have an influence on glucose levels, glucose homeostasis and insulin sensitivity, as insulin promotes glucose uptake through GLUT4. Type 2 Diabetes: Glucose intolerance is observed by 3-4 months followed by fasting hyperglycemia. Pancreases show advanced islet hyperplasia, concurrent with insulin resistance and type 2 diabetes. Pancreases of middle-age AR-19Q mice present with a significant islet hyperplasia, suggesting peripheral insulin resistance. We propose the use of the AR-19Q mice as a model to study the metabolic dysfunction/ deficiency leading to the MetS. The model will allow us to a better understanding into the mechanisms responsible for T2D and NAFLD-related disorders.

Presentation: 6/2/2024