Submitted by Joe Napoli on
Current worldwide epidemic of metabolic disorders calls for effective strategies for its prevention and treatment. Accumulating evidence from research laboratories and clinical studies show that overweight and obesity in animals and humans develop due to changes in energy and micronutrient metabolism, and cause further irreversible perturbations in energy metabolism leading to diabetes, cancer, neurodegenerative disorders, and other chronic diseases. Napoli laboratory studies vitamin A metabolism, and its role in regulating energy metabolism in the context of obesity, diabetes and neurodegenerative diseases. This particular SPUR project focuses on regulation of vitamin A metabolism in brown adipose tissue function and its role in regulating energy metabolism.
In my laboratory we are using modern genetics tools to inactivate or delete critical genes regulating vitamin A metabolism in mice. One of the models we are currently focusing on is a genetic deletion of retinol dehydrogenase 1 (rdh1) gene in the mouse. The Rdh1 protein functions as an enzyme, oxidizing vitamin A (retinol) into its metabolic intermediate retinal. Another class of enzymes called retinaldehyde dehydrogenases further oxidize retinal into all-trans retinoic acid (atRA), the active form of vitamin A. Retinoic acid binds directly to nuclear receptors in cells and regulate expression of more than 600 genes. Results form our laboratory showed that genetic deletion of rdh1 in the mouse initiates long-term metabolic changes in the liver and brown adipose tissue causing increased fat accumulation and weight gain compared to wild type age-matched control mice.
Our lab has previously evaluated phenotypic characteristics of adult mice with genetic deletion of rdh1 (Zhang et al., 2007). We showed that adult mice with genetic deletion of rdh1 experience disrupted vitamin A metabolism and storage in the liver and adipose tissue, which is negatively affecting their energy homeostasis leading to expansion of white adipose tissue in adulthood, even when the animals were fed low fat diet. Current studies are investigating role of rdh1 in brown adipocyte function, focusing on molecular mechanisms of triglyceride activation (induced lipolysis), and uptake of free fatty acids, as well as role of vitamin A metabolism in lipid droplet biology.
During Summer 2017 semester, a project scientist in my laboratory, Dr. Marta Vuckovic will use an in vitro primary cell culture model system to study molecular mechanisms of intracellular signaling that regulate lipid storage and mobilization in brown adipocytes from mice with genetic deletion of rdh1 and wild type control mice. Marta will isolate adipose tissue mesenchymal stem cells from kock-out and age-matched control mice, and induce cells to differentiate into mature adipocytes. Results of our recent studies indicate that primary adipocytes from rdh1 knockout mice show decreased ability to release free fatty acids into cell culture media, compared to WT control cells. This observation suggests rdh1 involvement in regulating lipid metabolism in brown adipocytes. We are currently focusing on dissecting cellular signaling in control of this process in brown adipocytes isolated from rdh1 knockout mice.
Interested students will have an excellent opportunity for hands-on training in basic techniques in histology, immunocytochemistry, molecular biology and cell culture, as well as mouse colony management. Students will assist a senior lab member in mouse colony maintenance, adipose tissue collection, adipose stem cells isolation, primary cell culture, differentiation procedures and retinoids assays. Depending on students’ ability to work at the bench, hands-on experience in protein expression techniques will be available. Students will work under close supervision of the senior lab member, and will be expected to keep a detailed lab journal regarding conducted experiments, read relevant research articles and attend weekly lab discussions. Students will be involved in data collection and analysis.
Applicant should be familiar with fundamentals of chemistry, biochemistry, molecular and cell biology and genetics, and show a strong interest in metabolism research. Previous experience in biology and chemistry laboratory in classroom settings is required. Ability to follow detailed protocols, pay close attention to experimental details, and learn quickly is necessary. Critical thinking and independent work is fostered and encouraged in our laboratory. Ability to work with live animals is desirable, and comprehensive training will be provided.