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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.


Related in: MedlinePlus

Ultrastructural localisation of Dfabp.Post-embedding silver-intensified immunogold labeling for Dfabp on freeze-substituted LR White-embedded material. An intense labeling can be seen over subperineurial (SPG) and superficial cortex (CG) glial cells. Note the absence of labeling over perineurial glia (PG), neurons (N), or neuroblasts (NB). Arrows: lipid droplets, arrowheads: mitochondria. Scalebar: 1 μm
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pone.0131250.g006: Ultrastructural localisation of Dfabp.Post-embedding silver-intensified immunogold labeling for Dfabp on freeze-substituted LR White-embedded material. An intense labeling can be seen over subperineurial (SPG) and superficial cortex (CG) glial cells. Note the absence of labeling over perineurial glia (PG), neurons (N), or neuroblasts (NB). Arrows: lipid droplets, arrowheads: mitochondria. Scalebar: 1 μm

Mentions: The Dfabp antibody showed a strong staining in a layer at the surface of the brain and also a deeper thin network likely to correspond to a subset of glial cells. The pattern of the immunoreactivity seemed to surround clusters of unlabeled cell bodies (Fig 5D). In addition, some cells located at the brain surface were immunonegative for Dfabp. To confirm the presumed glial localisation of Dfabp, we performed double labeling on larval brains against Dfabp and reverse polarity (Repo), a glial-specific protein [38]. Dfabp was detected in the cytoplasm and in the nucleoplasm of the Repo-positive glial cells (Fig 5E), while no labelling was obvesrved in neurons. Cortex glial cells are known to form a network between neurons, so this cell type seemed to be a good candidate to express Dfabp. To verify this, we immunostained Dfabp and the cortex glia of a transgenic line expressing NP2222-Gal4 driven GFP [39] (Fig 5F). The GFP signal overlapped with the Dfabp labeling, but another layer above the cortex glial cells was also immunoreactive for Dfabp, possibly representing the subperineurial glial layer. Perineurial cells located at the brain surface were negative for Dfabp. We wanted to confirm our light microscopic observations at the EM level as well. Accordingly, we carried out post-embedding immunogold labeling to determine the precise cellular and subcellular localisation of Dfabp. In the EM, we found cortex and subperineurial cells to be strongly immunoreactive for Dfabp, while perineurial cells, neuroblasts, and neurons were always immunonegative (Fig 6). In glial cells, Dfabp labeling was detected over the cytosol, nucleoplasm, and glycogen areas. No labeling was observed over mitochondria, ER, or LDs. Superficial cortex glial cells, containing numerous LDs, were always strongly immunopositive for Dfabp (Fig 6). We concluded that our Dfabp antibody selectively labels the subperineurial and the lipid accumulating superficial cortical glial cells in the third instar larval brain.


Specialized Cortex Glial Cells Accumulate Lipid Droplets in Drosophila melanogaster.

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

Ultrastructural localisation of Dfabp.Post-embedding silver-intensified immunogold labeling for Dfabp on freeze-substituted LR White-embedded material. An intense labeling can be seen over subperineurial (SPG) and superficial cortex (CG) glial cells. Note the absence of labeling over perineurial glia (PG), neurons (N), or neuroblasts (NB). Arrows: lipid droplets, arrowheads: mitochondria. Scalebar: 1 μm
© Copyright Policy
Related In: Results  -  Collection

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

pone.0131250.g006: Ultrastructural localisation of Dfabp.Post-embedding silver-intensified immunogold labeling for Dfabp on freeze-substituted LR White-embedded material. An intense labeling can be seen over subperineurial (SPG) and superficial cortex (CG) glial cells. Note the absence of labeling over perineurial glia (PG), neurons (N), or neuroblasts (NB). Arrows: lipid droplets, arrowheads: mitochondria. Scalebar: 1 μm
Mentions: The Dfabp antibody showed a strong staining in a layer at the surface of the brain and also a deeper thin network likely to correspond to a subset of glial cells. The pattern of the immunoreactivity seemed to surround clusters of unlabeled cell bodies (Fig 5D). In addition, some cells located at the brain surface were immunonegative for Dfabp. To confirm the presumed glial localisation of Dfabp, we performed double labeling on larval brains against Dfabp and reverse polarity (Repo), a glial-specific protein [38]. Dfabp was detected in the cytoplasm and in the nucleoplasm of the Repo-positive glial cells (Fig 5E), while no labelling was obvesrved in neurons. Cortex glial cells are known to form a network between neurons, so this cell type seemed to be a good candidate to express Dfabp. To verify this, we immunostained Dfabp and the cortex glia of a transgenic line expressing NP2222-Gal4 driven GFP [39] (Fig 5F). The GFP signal overlapped with the Dfabp labeling, but another layer above the cortex glial cells was also immunoreactive for Dfabp, possibly representing the subperineurial glial layer. Perineurial cells located at the brain surface were negative for Dfabp. We wanted to confirm our light microscopic observations at the EM level as well. Accordingly, we carried out post-embedding immunogold labeling to determine the precise cellular and subcellular localisation of Dfabp. In the EM, we found cortex and subperineurial cells to be strongly immunoreactive for Dfabp, while perineurial cells, neuroblasts, and neurons were always immunonegative (Fig 6). In glial cells, Dfabp labeling was detected over the cytosol, nucleoplasm, and glycogen areas. No labeling was observed over mitochondria, ER, or LDs. Superficial cortex glial cells, containing numerous LDs, were always strongly immunopositive for Dfabp (Fig 6). We concluded that our Dfabp antibody selectively labels the subperineurial and the lipid accumulating superficial cortical glial cells in the third instar larval brain.

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.


Related in: MedlinePlus