Specialized hepatocyte-like cells regulate Drosophila lipid metabolism

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Article

Nature advance online publication 29 November 2006 | doi:10.1038/nature05382; Received 22 July 2006; Accepted 23 October 2006; Published online 29 November 2006
Specialized hepatocyte-like cells regulate Drosophila lipid metabolism

Eugenio Gutierrez1, David Wiggins2, Barbara Fielding2 and Alex P. Gould1

1. Medical Research Council, National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, UK
2. Oxford Centre for Diabetes, Endocrinology and Metabolism, Churchill Hospital, Oxford OX3 7LJ, UK

Correspondence to: Alex P. Gould1 Correspondence and requests for materials should be addressed to A.P.G. (Email: agould@nimr.mrc.ac.uk).


Abstract

Lipid metabolism is essential for growth and generates much of the energy needed during periods of starvation. In Drosophila, fasting larvae release large quantities of lipid from the fat body but it is unclear how and where this is processed. Here we identify the oenocyte as the principal cell type accumulating lipid droplets during starvation. Tissue-specific manipulations of the Slimfast amino-acid channel, the Lsd2 fat-storage regulator and the Brummer lipase indicate that oenocytes act downstream of the fat body. In turn, oenocytes are required for depleting stored lipid from the fat body during fasting. Hence, lipid-metabolic coupling between the fat body and oenocytes is bidirectional. When food is plentiful, oenocytes have critical roles in regulating growth, development and feeding behaviour. In addition, they specifically express many different lipid-metabolizing proteins, including Cyp4g1, an -hydroxylase regulating triacylglycerol composition. These findings provide evidence that some lipid-processing functions of the mammalian liver are performed in insects by oenocytes.