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Stellate Cell Networks in the Teleost Pituitary.

Golan M, Hollander-Cohen L, Levavi-Sivan B - Sci Rep (2016)

Bottom Line: In the pars intermedia, stellate cells were arranged around neuronal bundles and their processes extended into the pars distalis.Within the pars distalis, stellate cells formed close associations with FSH cells and, to a lesser degree, with GH and LH cells, suggesting differential paracrine regulation of the two gonadotrope populations.The production of follistatin by stellate cells further corroborates the notion of a paracrine role on FSH release.

View Article: PubMed Central - PubMed

Affiliation: Department of Animal Sciences, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel.

ABSTRACT
The folliculostellate cells of the mammalian pituitary are non-endocrine cells that are implicated in long-distance communication and paracrine signaling, but to date, these cells have yet to be characterized in teleosts. We found that the stellate cells of the teleost pituitary share many common attributes with mammalian folliculostellate cells. By labeling of stellate cells in live preparations of tilapia pituitaries we investigated their distribution, association with other endocrine cells and their anatomical and functional coupling. In the pars intermedia, stellate cells were arranged around neuronal bundles and their processes extended into the pars distalis. Within the pars distalis, stellate cells formed close associations with FSH cells and, to a lesser degree, with GH and LH cells, suggesting differential paracrine regulation of the two gonadotrope populations. The production of follistatin by stellate cells further corroborates the notion of a paracrine role on FSH release. We also found stellate cells to form gap junctions that enabled dye transfer to neighboring stellate cells, implicating that these cells form a large-scale network that connects distant parts of the pituitary. Our findings represent the first wide-scale study of stellate cells in teleosts and provide valuable information regarding their functional roles in pituitary function.

No MeSH data available.


Related in: MedlinePlus

Stellate cells in the PPD and PI.(a) GH cell clumps (green) contain stellate cells (blue). (b) Stellate cells (asterisk) can be observed among immunogold-labeled somatotropes. (c) LH cell clumps (red) are largely devoid of stellate cells (blue). (d) In immunogold-labeled LH clumps, stellate cells (asterisk) can be observed mainly at the perimeter of the cell mass. (e) FSH cells (green) are closely associated with stellate cells (blue). (f) Cytoplasmic processes of stellate cells (asterisk) can be observed surrounding a FSH cell. Black arrows indicate irregular masses heavily stained with anti-tilapia FSH antibodies. (g) Quantification of the direct association of endocrine cells with stellate cells in the PPD. FSH and GH cells are significantly more directly contacted by stellate cells than LH cells. (h) A typical structure in the PI in which stellate cells (blue) surround a PN bundle in which pituicytes are immunostained for Cx 43 (green). While stellate cells do not penetrate the PN, they are situated on the perimeter of the bundle in a position that enables them to convey PN-borne messages into the pituitary parenchyma.
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f2: Stellate cells in the PPD and PI.(a) GH cell clumps (green) contain stellate cells (blue). (b) Stellate cells (asterisk) can be observed among immunogold-labeled somatotropes. (c) LH cell clumps (red) are largely devoid of stellate cells (blue). (d) In immunogold-labeled LH clumps, stellate cells (asterisk) can be observed mainly at the perimeter of the cell mass. (e) FSH cells (green) are closely associated with stellate cells (blue). (f) Cytoplasmic processes of stellate cells (asterisk) can be observed surrounding a FSH cell. Black arrows indicate irregular masses heavily stained with anti-tilapia FSH antibodies. (g) Quantification of the direct association of endocrine cells with stellate cells in the PPD. FSH and GH cells are significantly more directly contacted by stellate cells than LH cells. (h) A typical structure in the PI in which stellate cells (blue) surround a PN bundle in which pituicytes are immunostained for Cx 43 (green). While stellate cells do not penetrate the PN, they are situated on the perimeter of the bundle in a position that enables them to convey PN-borne messages into the pituitary parenchyma.

Mentions: The distribution of stellate cells within the PPD was not uniform. GH cells in tilapia are located in the dorsal side of the pituitary and surround the PN projections. In this area many AMCA labeled cells, both from the PN and in the PPD form close contacts with the somatotropes (Fig. 2a,b). The dense LH cell clumps were rarely infiltrated by stellate cells and their projections, although in some cases close associations could be observed, especially along the perimeter of the cell aggregates (Fig. 2c,d). In contrast, FSH cells were very closely associated with stellate cells (Fig. 2e,f). Quantification of the degree of association of stellate cells with the different cell types of the PPD showed that 90% of the FSH cells form direct contacts with stellate cells (90 ± 3.6% of 138 cells counted, n = 4), whereas two thirds of the GH (68.5 ± 6.16% of 633 cells counted, n = 5) and a third of LH (30 ± 3.1% of 674 cells counted, n = 4) cells were closely associated with stellate cells (Fig. 2g). Ultrastructural investigation of stellate cells and immunogold labeled endocrine cells further corroborated these observations (Fig. 2b,d,f).


Stellate Cell Networks in the Teleost Pituitary.

Golan M, Hollander-Cohen L, Levavi-Sivan B - Sci Rep (2016)

Stellate cells in the PPD and PI.(a) GH cell clumps (green) contain stellate cells (blue). (b) Stellate cells (asterisk) can be observed among immunogold-labeled somatotropes. (c) LH cell clumps (red) are largely devoid of stellate cells (blue). (d) In immunogold-labeled LH clumps, stellate cells (asterisk) can be observed mainly at the perimeter of the cell mass. (e) FSH cells (green) are closely associated with stellate cells (blue). (f) Cytoplasmic processes of stellate cells (asterisk) can be observed surrounding a FSH cell. Black arrows indicate irregular masses heavily stained with anti-tilapia FSH antibodies. (g) Quantification of the direct association of endocrine cells with stellate cells in the PPD. FSH and GH cells are significantly more directly contacted by stellate cells than LH cells. (h) A typical structure in the PI in which stellate cells (blue) surround a PN bundle in which pituicytes are immunostained for Cx 43 (green). While stellate cells do not penetrate the PN, they are situated on the perimeter of the bundle in a position that enables them to convey PN-borne messages into the pituitary parenchyma.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4834476&req=5

f2: Stellate cells in the PPD and PI.(a) GH cell clumps (green) contain stellate cells (blue). (b) Stellate cells (asterisk) can be observed among immunogold-labeled somatotropes. (c) LH cell clumps (red) are largely devoid of stellate cells (blue). (d) In immunogold-labeled LH clumps, stellate cells (asterisk) can be observed mainly at the perimeter of the cell mass. (e) FSH cells (green) are closely associated with stellate cells (blue). (f) Cytoplasmic processes of stellate cells (asterisk) can be observed surrounding a FSH cell. Black arrows indicate irregular masses heavily stained with anti-tilapia FSH antibodies. (g) Quantification of the direct association of endocrine cells with stellate cells in the PPD. FSH and GH cells are significantly more directly contacted by stellate cells than LH cells. (h) A typical structure in the PI in which stellate cells (blue) surround a PN bundle in which pituicytes are immunostained for Cx 43 (green). While stellate cells do not penetrate the PN, they are situated on the perimeter of the bundle in a position that enables them to convey PN-borne messages into the pituitary parenchyma.
Mentions: The distribution of stellate cells within the PPD was not uniform. GH cells in tilapia are located in the dorsal side of the pituitary and surround the PN projections. In this area many AMCA labeled cells, both from the PN and in the PPD form close contacts with the somatotropes (Fig. 2a,b). The dense LH cell clumps were rarely infiltrated by stellate cells and their projections, although in some cases close associations could be observed, especially along the perimeter of the cell aggregates (Fig. 2c,d). In contrast, FSH cells were very closely associated with stellate cells (Fig. 2e,f). Quantification of the degree of association of stellate cells with the different cell types of the PPD showed that 90% of the FSH cells form direct contacts with stellate cells (90 ± 3.6% of 138 cells counted, n = 4), whereas two thirds of the GH (68.5 ± 6.16% of 633 cells counted, n = 5) and a third of LH (30 ± 3.1% of 674 cells counted, n = 4) cells were closely associated with stellate cells (Fig. 2g). Ultrastructural investigation of stellate cells and immunogold labeled endocrine cells further corroborated these observations (Fig. 2b,d,f).

Bottom Line: In the pars intermedia, stellate cells were arranged around neuronal bundles and their processes extended into the pars distalis.Within the pars distalis, stellate cells formed close associations with FSH cells and, to a lesser degree, with GH and LH cells, suggesting differential paracrine regulation of the two gonadotrope populations.The production of follistatin by stellate cells further corroborates the notion of a paracrine role on FSH release.

View Article: PubMed Central - PubMed

Affiliation: Department of Animal Sciences, The Robert H. Smith Faculty of Agriculture, Food and Environment, The Hebrew University of Jerusalem, Rehovot 76100, Israel.

ABSTRACT
The folliculostellate cells of the mammalian pituitary are non-endocrine cells that are implicated in long-distance communication and paracrine signaling, but to date, these cells have yet to be characterized in teleosts. We found that the stellate cells of the teleost pituitary share many common attributes with mammalian folliculostellate cells. By labeling of stellate cells in live preparations of tilapia pituitaries we investigated their distribution, association with other endocrine cells and their anatomical and functional coupling. In the pars intermedia, stellate cells were arranged around neuronal bundles and their processes extended into the pars distalis. Within the pars distalis, stellate cells formed close associations with FSH cells and, to a lesser degree, with GH and LH cells, suggesting differential paracrine regulation of the two gonadotrope populations. The production of follistatin by stellate cells further corroborates the notion of a paracrine role on FSH release. We also found stellate cells to form gap junctions that enabled dye transfer to neighboring stellate cells, implicating that these cells form a large-scale network that connects distant parts of the pituitary. Our findings represent the first wide-scale study of stellate cells in teleosts and provide valuable information regarding their functional roles in pituitary function.

No MeSH data available.


Related in: MedlinePlus