SELECTED PUBLICATIONS IN OBESITY
Energy is stored in the form of fat when food is available. When food becomes scarce organims activate genetic programs that maximize their chances of survival until food becomes again available. Unbiased genome searches allow us to discover a molecular switch that promotes fat accumulation while food is availble and fat utilization during fasting. Animals that cannot activate this survival program die prematurely of starvation. This program orchestrated by the transcription factors mxl-3 and hlh-30 is conserved in worms, flies, mice and human cells in culture. Therefore, this ancient metabolic program could become a target for the treatment of metabolic disease in humans.
Genetic conservation allows ancient features of fat storage endocrine pathways to be explored in C. elegans. Multiple studies have used Nile red or BODIPY-labeled fatty acids to identify regulators of fat mass. When mixed with their food, E. coli bacteria, Nile red, and BODIPY-labeled fatty acids stain multiple spherical cellular structures in the C. elegans major fat storage organ, the intestine. However, here we demonstrate that, in the conditions previously reported, the lysosome-related organelles stained by Nile red and BODIPY-labeled fatty acids are not the C. elegans major fat storage compartment. We show that the major fat stores are contained in a distinct cellular compartment that is not stained by Nile red. Using biochemical assays, we validate oil red O staining as a method to assess major fat stores in C. elegans, allowing for efficient and accurate genetic and functional genomic screens for genes that control fat accumulation at the organismal level.
We report a method, named FLAHCoS (fat live animal high-content screnning), that enables high-throughput image-based scoring of C. elegans total body fat mass and distribution. We also describe a scaled-down version of the methodology for small scale experiments or laboratory classes. We are currently using this method to uncover all genes affecting fat accumulation in a living animal.
We present a toolbox for high-throughput screening of image-based Caenorhabditis elegans phenotypes. The image analysis algorithms measure morphological phenotypes in individual worms and are effective for a variety of assays and imaging systems. This WormToolbox is available through the open-source CellProfiler project and enables objective scoring of whole-worm high-throughput image-based assays of C. elegans for the study of diverse biological pathways that are relevant to human disease.