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Taste Bud-Derived BDNF Is Required to Maintain Normal Amounts of Innervation to Adult Taste Buds.

Meng L, Ohman-Gault L, Ma L, Krimm RF - eNeuro (2015)

Bottom Line: We then tested the idea that that the taste bud was the source of this BDNF by reducing Bdnf levels specifically in the lingual epithelium and taste buds.Taste buds were confirmed as the source of BDNF regulating innervation.We conclude that BDNF expressed in taste receptor cells is required to maintain normal levels of innervation in adulthood.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine , Louisville, Kentucky 40292.

ABSTRACT
Gustatory neurons transmit chemical information from taste receptor cells, which reside in taste buds in the oral cavity, to the brain. As adult taste receptor cells are renewed at a constant rate, nerve fibers must reconnect with new taste receptor cells as they arise. Therefore, the maintenance of gustatory innervation to the taste bud is an active process. Understanding how this process is regulated is a fundamental concern of gustatory system biology. We speculated that because brain-derived neurotrophic factor (BDNF) is required for taste bud innervation during development, it might function to maintain innervation during adulthood. If so, taste buds should lose innervation when Bdnf is deleted in adult mice. To test this idea, we first removed Bdnf from all cells in adulthood using transgenic mice with inducible CreERT2 under the control of the Ubiquitin promoter. When Bdnf was removed, approximately one-half of the innervation to taste buds was lost, and taste buds became smaller because of the loss of taste bud cells. Individual taste buds varied in the amount of innervation each lost, and those that lost the most innervation also lost the most taste bud cells. We then tested the idea that that the taste bud was the source of this BDNF by reducing Bdnf levels specifically in the lingual epithelium and taste buds. Taste buds were confirmed as the source of BDNF regulating innervation. We conclude that BDNF expressed in taste receptor cells is required to maintain normal levels of innervation in adulthood.

No MeSH data available.


Related in: MedlinePlus

Diagram illustrating a possible role of BDNF during adulthood. A, Some taste bud cells express BDNF (blue), whereas others do not (tan). BDNF in new taste cells (dark blue) attracts a subset of geniculate afferents (yellow arrow), which form functional connections with these taste cells. Taste neurons likely release some factor that maintains at least some taste cells (purple arrow). B, When new taste cells no longer express BDNF, they fail to attract new innervation (dashed fiber); however, mature taste cells no longer expressing BDNF that have already been innervated are unaffected. C, Given sufficient time following BDNF gene deletion, all BDNF-expressing taste receptor cells are replaced with cells that no longer express BDNF. As a result, innervation is reduced, and this loss of innervation results in a reduction in taste bud size and cell number.
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Figure 9: Diagram illustrating a possible role of BDNF during adulthood. A, Some taste bud cells express BDNF (blue), whereas others do not (tan). BDNF in new taste cells (dark blue) attracts a subset of geniculate afferents (yellow arrow), which form functional connections with these taste cells. Taste neurons likely release some factor that maintains at least some taste cells (purple arrow). B, When new taste cells no longer express BDNF, they fail to attract new innervation (dashed fiber); however, mature taste cells no longer expressing BDNF that have already been innervated are unaffected. C, Given sufficient time following BDNF gene deletion, all BDNF-expressing taste receptor cells are replaced with cells that no longer express BDNF. As a result, innervation is reduced, and this loss of innervation results in a reduction in taste bud size and cell number.


Taste Bud-Derived BDNF Is Required to Maintain Normal Amounts of Innervation to Adult Taste Buds.

Meng L, Ohman-Gault L, Ma L, Krimm RF - eNeuro (2015)

Diagram illustrating a possible role of BDNF during adulthood. A, Some taste bud cells express BDNF (blue), whereas others do not (tan). BDNF in new taste cells (dark blue) attracts a subset of geniculate afferents (yellow arrow), which form functional connections with these taste cells. Taste neurons likely release some factor that maintains at least some taste cells (purple arrow). B, When new taste cells no longer express BDNF, they fail to attract new innervation (dashed fiber); however, mature taste cells no longer expressing BDNF that have already been innervated are unaffected. C, Given sufficient time following BDNF gene deletion, all BDNF-expressing taste receptor cells are replaced with cells that no longer express BDNF. As a result, innervation is reduced, and this loss of innervation results in a reduction in taste bud size and cell number.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4697083&req=5

Figure 9: Diagram illustrating a possible role of BDNF during adulthood. A, Some taste bud cells express BDNF (blue), whereas others do not (tan). BDNF in new taste cells (dark blue) attracts a subset of geniculate afferents (yellow arrow), which form functional connections with these taste cells. Taste neurons likely release some factor that maintains at least some taste cells (purple arrow). B, When new taste cells no longer express BDNF, they fail to attract new innervation (dashed fiber); however, mature taste cells no longer expressing BDNF that have already been innervated are unaffected. C, Given sufficient time following BDNF gene deletion, all BDNF-expressing taste receptor cells are replaced with cells that no longer express BDNF. As a result, innervation is reduced, and this loss of innervation results in a reduction in taste bud size and cell number.
Bottom Line: We then tested the idea that that the taste bud was the source of this BDNF by reducing Bdnf levels specifically in the lingual epithelium and taste buds.Taste buds were confirmed as the source of BDNF regulating innervation.We conclude that BDNF expressed in taste receptor cells is required to maintain normal levels of innervation in adulthood.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine , Louisville, Kentucky 40292.

ABSTRACT
Gustatory neurons transmit chemical information from taste receptor cells, which reside in taste buds in the oral cavity, to the brain. As adult taste receptor cells are renewed at a constant rate, nerve fibers must reconnect with new taste receptor cells as they arise. Therefore, the maintenance of gustatory innervation to the taste bud is an active process. Understanding how this process is regulated is a fundamental concern of gustatory system biology. We speculated that because brain-derived neurotrophic factor (BDNF) is required for taste bud innervation during development, it might function to maintain innervation during adulthood. If so, taste buds should lose innervation when Bdnf is deleted in adult mice. To test this idea, we first removed Bdnf from all cells in adulthood using transgenic mice with inducible CreERT2 under the control of the Ubiquitin promoter. When Bdnf was removed, approximately one-half of the innervation to taste buds was lost, and taste buds became smaller because of the loss of taste bud cells. Individual taste buds varied in the amount of innervation each lost, and those that lost the most innervation also lost the most taste bud cells. We then tested the idea that that the taste bud was the source of this BDNF by reducing Bdnf levels specifically in the lingual epithelium and taste buds. Taste buds were confirmed as the source of BDNF regulating innervation. We conclude that BDNF expressed in taste receptor cells is required to maintain normal levels of innervation in adulthood.

No MeSH data available.


Related in: MedlinePlus