Energy homeostasis: genes and environment
Energy homeostasis is a vital regulatory process that enables animals and humans to maintain a constant metabolism. The availability and composition of food are subject to constant fluctuations, as is the organism's energy consumption, whether due to changing environmental conditions or changes in behavior. If the energy supply outweighs consumption, storage substances are stored. In phases of negative energy balance, on the other hand, a constant internal energy level is ensured by mobilizing these energy storage substances, above all body fat.
But how does the body manage the storage of fat and its mobilization as needed? How does the body perceive changes in environmental conditions and how does it adapt to them? How do the body's organs communicate the energy status within the organism? How does the organism know the target value of the body fat store?
Answering these questions requires an understanding of the genetic architecture of energy homeostasis and its interaction with environmental influences. Our research group therefore uses the fruit fly Drosophila melanogaster, a model organism with excellent genetic accessibility.
"Lean" and "fat" Drosophila flies
Drosophila stores fats in the form of so-called lipid droplets within specialized cells of a storage organ called the fat body. Just as in mammals, the amount of lipids stored in the fat body varies greatly in Drosophila depending on the genetic constitution and the given environmental conditions, resulting in "lean" or "fat" flies.
We use these "lean" and "fat" flies to identify and functionally characterize regulatory genes of lipid metabolism using a broad spectrum of methods ranging from molecular biology to behavioural studies and lipidomics.
Fat metabolism near freezing point: the glacier insect Andiperla morenensis
Evolutionary adaptation to extreme living conditions enables the occupation of new ecological niches. A fascinating example of this is the stonefly Andiperla morenenis, the only insect that spends its entire life on the glaciers of the southern Patagonian ice field. Since Andiperla, like all insects, cannot actively regulate its body temperature, life near freezing point requires far-reaching adaptations of the storage fat and membrane lipid metabolism, which we are investigating as part of an international cooperation project.
Our Drosophila research elucidates fundamental principles of organismal lipid metabolism, which contributes significantly to energy homeostasis. As our research has shown, the principles of energy homeostasis are remarkably conserved in evolutionary terms. Therefore, the insights gained from the fly and other insects are relevant for current societal challenges such as human lipid metabolic diseases (especially obesity) or the spread of insect pests or the loss of biodiversity under the conditions of climate change.