Lipid droplets (LDs) are common organelles of the majority of eukaryotic cell types.
Their biological significance has been extensively studied in mammalian liver cells
and white adipose tissue. Although the central nervous system contains the highest
relative amount and the largest number of different lipid species, neither the spatial
nor the temporal distribution of LDs has been described. In this study, we used the
brain of the fruitfly, Drosophila melanogaster, to investigate the neuroanatomy of
LDs. We demonstrated that LDs are exclusively localised in glial cells but not in
neurons in the larval nervous system. We showed that the brain's LD pool, rather than
being constant, changes dynamically during development and reaches its highest value
at the beginning of metamorphosis. LDs are particularly enriched in cortex glial cells
located close to the brain surface. These specialized superficial cortex glial cells
contain the highest amount of LDs among glial cell types and encapsulate neuroblasts
and their daughter cells. Superficial cortex glial cells, combined with subperineurial
glial cells, express the Drosophila fatty acid binding protein (Dfabp), as we have
demonstrated through light-and electron microscopic immunocytochemistry. To the best
of our best knowledge this is the first study that describes LD neuroanatomy in the
Drosophila larval brain.
