Subterranean Fishes of the World

4284

2019

AIM 2019

36

Obesity is one of the largest worldwide epidemics - in the United States alone it is estimated to affect roughly forty percent of the population. Chronic subcutaneous and visceral fat deposition frequently leads to additional diseases including diabetes and cardiovascular complications. While several animal models have been developed to investigate fat accumulation disorders, the molecular mechanisms responsible for orchestrating muscle loss and subcutaneous fat accumulation are mostly unknown. We are using the Mexican cavefish as a useful new model to help understand the molecular regulation of and changes associated with chronic obesity. Cave morphs of Astyanax mexicanus evolved recently from surface fish after being isolated in cold, dark, and nutrient-deprived Mexican caves. In order to thrive in this unique environment, cave morphs evolved a number of morphological, physiological, and behavioral adaptations relevant to human disease conditions such as loss of eyes, obesity, and repetitive swimming behavior. Naturally obese cave morphs of Astyanax mexicanus provide a unique opportunity to study the molecular mechanisms behind adipocyte differentiation and fat deposition. Here, we report that cavefish embryos initiate excess adipocyte differentiation-specific gene expression as early as one and half days of development, and maintain this throughout their development. The excess adipocyte differentiation in cave morphs also appears to be linked to reduced muscle mass compared to surface fish. Using single-cell RNA seq analysis, we are investigating differences in the cellular identities and differentiation programs between surface and cave embryos. We will discuss our preliminary findings on cave and surface fish fat deposition and muscle specification.

1

Astyanax Interrnational Meeting