Limits...
Specialized Cortex Glial Cells Accumulate Lipid Droplets in Drosophila melanogaster.

Kis V, Barti B, Lippai M, Sass M - PLoS ONE (2015)

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest, Hungary.

ABSTRACT
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.

No MeSH data available.


Lipid droplets in the Drosophila brain.(A-E) Pictures taken from third instar larval brains. (A) Oil Red O staining, note an intense staining in the dorso-medial part of the central brain. (B) Toluidine blue-stained semithin section from the brain cortex. LDs (green) are organized in large clusters between neurons. (C) Pseudocolored electron micrograph taken from the brain cortex. LDs (green) are found in the cytoplasm of glial cells (G, red) but not in neurons (N). (D) High power electron micrograph from the perinuclear region of a cortex glia (G) LDs are rounded electron-opaque structures, delineated by a phospholipid monolayer (inset, arrow). N: neuron. (E) LDs (brown) are generally found in the closest vicinity of neuroblasts (asterisks). Unstained semithin section. (F) Diagram representing the distribution of LDs between neurons and glial cells. (G) Number of LDs in order of their distance from neuroblasts. (H) Time-course changes in the amount of accumulated LDs per brain tissue area ratio. Standard deviations are indicated. Scalebars: (A) 100 μm (B) 10 μm (C) 1μm, (D) 500nm, inset: 200nm, (E) 10 μm.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4493057&req=5

pone.0131250.g001: Lipid droplets in the Drosophila brain.(A-E) Pictures taken from third instar larval brains. (A) Oil Red O staining, note an intense staining in the dorso-medial part of the central brain. (B) Toluidine blue-stained semithin section from the brain cortex. LDs (green) are organized in large clusters between neurons. (C) Pseudocolored electron micrograph taken from the brain cortex. LDs (green) are found in the cytoplasm of glial cells (G, red) but not in neurons (N). (D) High power electron micrograph from the perinuclear region of a cortex glia (G) LDs are rounded electron-opaque structures, delineated by a phospholipid monolayer (inset, arrow). N: neuron. (E) LDs (brown) are generally found in the closest vicinity of neuroblasts (asterisks). Unstained semithin section. (F) Diagram representing the distribution of LDs between neurons and glial cells. (G) Number of LDs in order of their distance from neuroblasts. (H) Time-course changes in the amount of accumulated LDs per brain tissue area ratio. Standard deviations are indicated. Scalebars: (A) 100 μm (B) 10 μm (C) 1μm, (D) 500nm, inset: 200nm, (E) 10 μm.

Mentions: To visualize the lipid droplets, we stained third instar larval brains with Oil Red O, a traditional neutral lipid dye. LDs were present throughout the entire brain but were preferentially enriched in the medial part of the central brain (Fig 1A). As the density of LDs was highest in this brain area, our research focused on this particular region. We found LDs to be organized in large clusters in resin sections stained with toluidine blue, which stains LDs green in a metachromatic manner (Fig 1B). In the electron microscope (EM), LDs were found exclusively in the glial cells, which could be identified on the basis of their heterochromatic nucleus and dense cytoplasm packed with ribosomes [24] (Fig 1C). To validate the glial nature of the lipid accumulating cells in the brain, we labeled glial membranes with membrane targeted HRP (S1 Fig). The LDs found in Drosophila glial cells shared the properties of LDs observed in mammals: homogenous electron-opaque staining and delineation by a phospholipid monolayer [25] (Fig 1D) The LDs were concentrated mostly in the perinuclear region of glial cells (Fig 1C and 1D). Remarkably, no LDs were found in neurons (2483 LDs counted from 15 brains, Fig 1F).


Specialized Cortex Glial Cells Accumulate Lipid Droplets in Drosophila melanogaster.

Kis V, Barti B, Lippai M, Sass M - PLoS ONE (2015)

Lipid droplets in the Drosophila brain.(A-E) Pictures taken from third instar larval brains. (A) Oil Red O staining, note an intense staining in the dorso-medial part of the central brain. (B) Toluidine blue-stained semithin section from the brain cortex. LDs (green) are organized in large clusters between neurons. (C) Pseudocolored electron micrograph taken from the brain cortex. LDs (green) are found in the cytoplasm of glial cells (G, red) but not in neurons (N). (D) High power electron micrograph from the perinuclear region of a cortex glia (G) LDs are rounded electron-opaque structures, delineated by a phospholipid monolayer (inset, arrow). N: neuron. (E) LDs (brown) are generally found in the closest vicinity of neuroblasts (asterisks). Unstained semithin section. (F) Diagram representing the distribution of LDs between neurons and glial cells. (G) Number of LDs in order of their distance from neuroblasts. (H) Time-course changes in the amount of accumulated LDs per brain tissue area ratio. Standard deviations are indicated. Scalebars: (A) 100 μm (B) 10 μm (C) 1μm, (D) 500nm, inset: 200nm, (E) 10 μm.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493057&req=5

pone.0131250.g001: Lipid droplets in the Drosophila brain.(A-E) Pictures taken from third instar larval brains. (A) Oil Red O staining, note an intense staining in the dorso-medial part of the central brain. (B) Toluidine blue-stained semithin section from the brain cortex. LDs (green) are organized in large clusters between neurons. (C) Pseudocolored electron micrograph taken from the brain cortex. LDs (green) are found in the cytoplasm of glial cells (G, red) but not in neurons (N). (D) High power electron micrograph from the perinuclear region of a cortex glia (G) LDs are rounded electron-opaque structures, delineated by a phospholipid monolayer (inset, arrow). N: neuron. (E) LDs (brown) are generally found in the closest vicinity of neuroblasts (asterisks). Unstained semithin section. (F) Diagram representing the distribution of LDs between neurons and glial cells. (G) Number of LDs in order of their distance from neuroblasts. (H) Time-course changes in the amount of accumulated LDs per brain tissue area ratio. Standard deviations are indicated. Scalebars: (A) 100 μm (B) 10 μm (C) 1μm, (D) 500nm, inset: 200nm, (E) 10 μm.
Mentions: To visualize the lipid droplets, we stained third instar larval brains with Oil Red O, a traditional neutral lipid dye. LDs were present throughout the entire brain but were preferentially enriched in the medial part of the central brain (Fig 1A). As the density of LDs was highest in this brain area, our research focused on this particular region. We found LDs to be organized in large clusters in resin sections stained with toluidine blue, which stains LDs green in a metachromatic manner (Fig 1B). In the electron microscope (EM), LDs were found exclusively in the glial cells, which could be identified on the basis of their heterochromatic nucleus and dense cytoplasm packed with ribosomes [24] (Fig 1C). To validate the glial nature of the lipid accumulating cells in the brain, we labeled glial membranes with membrane targeted HRP (S1 Fig). The LDs found in Drosophila glial cells shared the properties of LDs observed in mammals: homogenous electron-opaque staining and delineation by a phospholipid monolayer [25] (Fig 1D) The LDs were concentrated mostly in the perinuclear region of glial cells (Fig 1C and 1D). Remarkably, no LDs were found in neurons (2483 LDs counted from 15 brains, Fig 1F).

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Department of Anatomy, Cell and Developmental Biology, Eötvös Loránd University, Budapest, Hungary.

ABSTRACT
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.

No MeSH data available.