Limits...
Cholinergic epithelial cell with chemosensory traits in murine thymic medulla.

Panneck AR, Rafiq A, Schütz B, Soultanova A, Deckmann K, Chubanov V, Gudermann T, Weihe E, Krasteva-Christ G, Grau V, del Rey A, Kummer W - Cell Tissue Res. (2014)

Bottom Line: ChAT expression was confirmed by in situ hybridization.They did not express neuroendocrine (chromogranin A, PGP9.5) or thymocyte (CD3) markers but rather thymic epithelial (CK8, CK18) markers and were immunoreactive for components of the taste transduction cascade such as Gα-gustducin, transient receptor potential melastatin-like subtype 5 channel (TRPM5), and phospholipase Cβ2.This cell might participate in intrathymic infection-sensing mechanisms.

View Article: PubMed Central - PubMed

Affiliation: Institute of Anatomy and Cell Biology, Justus-Liebig-University Giessen, Aulweg 123, 35385, Giessen, Germany.

ABSTRACT
Specialized epithelial cells with a tuft of apical microvilli ("brush cells") sense luminal content and initiate protective reflexes in response to potentially harmful substances. They utilize the canonical taste transduction cascade to detect "bitter" substances such as bacterial quorum-sensing molecules. In the respiratory tract, most of these cells are cholinergic and are approached by cholinoceptive sensory nerve fibers. Utilizing two different reporter mouse strains for the expression of choline acetyltransferase (ChAT), we observed intense labeling of a subset of thymic medullary cells. ChAT expression was confirmed by in situ hybridization. These cells showed expression of villin, a brush cell marker protein, and ultrastructurally exhibited lateral microvilli. They did not express neuroendocrine (chromogranin A, PGP9.5) or thymocyte (CD3) markers but rather thymic epithelial (CK8, CK18) markers and were immunoreactive for components of the taste transduction cascade such as Gα-gustducin, transient receptor potential melastatin-like subtype 5 channel (TRPM5), and phospholipase Cβ2. Reverse transcription and polymerase chain reaction confirmed the expression of Gα-gustducin, TRPM5, and phospholipase Cβ2. Thymic "cholinergic chemosensory cells" were often in direct contact with medullary epithelial cells expressing the nicotinic acetylcholine receptor subunit α3. These cells have recently been identified as terminally differentiated epithelial cells (Hassall's corpuscle-like structures in mice). Contacts with nerve fibers (identified by PGP9.5 and CGRP antibodies), however, were not observed. Our data identify, in the thymus, a previously unrecognized presumptive chemosensitive cell that probably utilizes acetylcholine for paracrine signaling. This cell might participate in intrathymic infection-sensing mechanisms.

Show MeSH
Cells expressing the nicotinic ACh receptor (nAChR) α3-subunit often are in close proximity to presumptive chemoreceptive cells. a, b nAChRα3-eGFP-fluorescence. a Positive cells are scattered throughout the medulla. b Nerve fibers enmesh a small septal artery. c–f nAChRα3-eGFP-positive cells lying next to cells immunoreactive for villin (c), α-gustducin (d), PLCβ2 (e), and TRPM5 (f). a, b Male aged 6 weeks. c, d Male aged 14 weeks. e, f Female aged 8 weeks. Bars 50 μm (a, b), 20 μm (c–f)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4233111&req=5

Fig6: Cells expressing the nicotinic ACh receptor (nAChR) α3-subunit often are in close proximity to presumptive chemoreceptive cells. a, b nAChRα3-eGFP-fluorescence. a Positive cells are scattered throughout the medulla. b Nerve fibers enmesh a small septal artery. c–f nAChRα3-eGFP-positive cells lying next to cells immunoreactive for villin (c), α-gustducin (d), PLCβ2 (e), and TRPM5 (f). a, b Male aged 6 weeks. c, d Male aged 14 weeks. e, f Female aged 8 weeks. Bars 50 μm (a, b), 20 μm (c–f)

Mentions: In the respiratory and urethral epithelium, sensory nerve fibers expressing the nAChRα3-subunit establish direct contacts with chemosensory cells (Krasteva et al. 2011; Deckmann et al. 2014). Utilizing the same Chrna3BAC-eGFP mouse strain as in these previous studies, we noted positive perivascular axons and nerve fibers in the septa, but not in the thymic medulla unrelated to vessels. As also reported recently (Soultanova et al. 2014), however, nAChRα3-subunit-positive epithelial medullary cells were seen (Fig. 6a, b). Co-immunolabeling with antibodies directed against villin and the components of the taste transduction cascade (Gα-gustducin, PLCβ2, and TRPM5) revealed that presumptive chemosensory cells and nAChRα3-subunit-expressing cells often formed small clusters and were in immediate contact with each other but always represented distinct cell populations (Fig. 6c–f).Fig. 6


Cholinergic epithelial cell with chemosensory traits in murine thymic medulla.

Panneck AR, Rafiq A, Schütz B, Soultanova A, Deckmann K, Chubanov V, Gudermann T, Weihe E, Krasteva-Christ G, Grau V, del Rey A, Kummer W - Cell Tissue Res. (2014)

Cells expressing the nicotinic ACh receptor (nAChR) α3-subunit often are in close proximity to presumptive chemoreceptive cells. a, b nAChRα3-eGFP-fluorescence. a Positive cells are scattered throughout the medulla. b Nerve fibers enmesh a small septal artery. c–f nAChRα3-eGFP-positive cells lying next to cells immunoreactive for villin (c), α-gustducin (d), PLCβ2 (e), and TRPM5 (f). a, b Male aged 6 weeks. c, d Male aged 14 weeks. e, f Female aged 8 weeks. Bars 50 μm (a, b), 20 μm (c–f)
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4233111&req=5

Fig6: Cells expressing the nicotinic ACh receptor (nAChR) α3-subunit often are in close proximity to presumptive chemoreceptive cells. a, b nAChRα3-eGFP-fluorescence. a Positive cells are scattered throughout the medulla. b Nerve fibers enmesh a small septal artery. c–f nAChRα3-eGFP-positive cells lying next to cells immunoreactive for villin (c), α-gustducin (d), PLCβ2 (e), and TRPM5 (f). a, b Male aged 6 weeks. c, d Male aged 14 weeks. e, f Female aged 8 weeks. Bars 50 μm (a, b), 20 μm (c–f)
Mentions: In the respiratory and urethral epithelium, sensory nerve fibers expressing the nAChRα3-subunit establish direct contacts with chemosensory cells (Krasteva et al. 2011; Deckmann et al. 2014). Utilizing the same Chrna3BAC-eGFP mouse strain as in these previous studies, we noted positive perivascular axons and nerve fibers in the septa, but not in the thymic medulla unrelated to vessels. As also reported recently (Soultanova et al. 2014), however, nAChRα3-subunit-positive epithelial medullary cells were seen (Fig. 6a, b). Co-immunolabeling with antibodies directed against villin and the components of the taste transduction cascade (Gα-gustducin, PLCβ2, and TRPM5) revealed that presumptive chemosensory cells and nAChRα3-subunit-expressing cells often formed small clusters and were in immediate contact with each other but always represented distinct cell populations (Fig. 6c–f).Fig. 6

Bottom Line: ChAT expression was confirmed by in situ hybridization.They did not express neuroendocrine (chromogranin A, PGP9.5) or thymocyte (CD3) markers but rather thymic epithelial (CK8, CK18) markers and were immunoreactive for components of the taste transduction cascade such as Gα-gustducin, transient receptor potential melastatin-like subtype 5 channel (TRPM5), and phospholipase Cβ2.This cell might participate in intrathymic infection-sensing mechanisms.

View Article: PubMed Central - PubMed

Affiliation: Institute of Anatomy and Cell Biology, Justus-Liebig-University Giessen, Aulweg 123, 35385, Giessen, Germany.

ABSTRACT
Specialized epithelial cells with a tuft of apical microvilli ("brush cells") sense luminal content and initiate protective reflexes in response to potentially harmful substances. They utilize the canonical taste transduction cascade to detect "bitter" substances such as bacterial quorum-sensing molecules. In the respiratory tract, most of these cells are cholinergic and are approached by cholinoceptive sensory nerve fibers. Utilizing two different reporter mouse strains for the expression of choline acetyltransferase (ChAT), we observed intense labeling of a subset of thymic medullary cells. ChAT expression was confirmed by in situ hybridization. These cells showed expression of villin, a brush cell marker protein, and ultrastructurally exhibited lateral microvilli. They did not express neuroendocrine (chromogranin A, PGP9.5) or thymocyte (CD3) markers but rather thymic epithelial (CK8, CK18) markers and were immunoreactive for components of the taste transduction cascade such as Gα-gustducin, transient receptor potential melastatin-like subtype 5 channel (TRPM5), and phospholipase Cβ2. Reverse transcription and polymerase chain reaction confirmed the expression of Gα-gustducin, TRPM5, and phospholipase Cβ2. Thymic "cholinergic chemosensory cells" were often in direct contact with medullary epithelial cells expressing the nicotinic acetylcholine receptor subunit α3. These cells have recently been identified as terminally differentiated epithelial cells (Hassall's corpuscle-like structures in mice). Contacts with nerve fibers (identified by PGP9.5 and CGRP antibodies), however, were not observed. Our data identify, in the thymus, a previously unrecognized presumptive chemosensitive cell that probably utilizes acetylcholine for paracrine signaling. This cell might participate in intrathymic infection-sensing mechanisms.

Show MeSH