title: TAK1 expression in the cochlea: a specific marker for adult supporting cells.
abstract: Transforming growth factor-β-activated kinase-1 (TAK1) is a mitogen activated protein kinase kinase kinase that is involved in diverse biological roles across species. Functioning downstream of TGF-β and BMP signaling, TAK1 mediates the activation of the c-Jun N-terminal kinase signaling pathway, serves as the target of pro-inflammatory cytokines, such as TNF-α, mediates NF-κβ activation, and plays a role in Wnt/Fz signaling in mesenchymal stem cells. Expression of TAK1 in the cochlea has not been defined. Data mining of previously published murine cochlear gene expression databases indicated that TAK1, along with TAK1 interacting proteins 1 (TAB1), and 2 (TAB2), is expressed in the developing and adult cochlea. The expression of TAK1 in the developing cochlea was confirmed using RT-PCR and immunohistochemistry. Immunolabeling of TAK1 in embryonic, neonatal, and mature cochleas via DAB chromogenic and fluorescent immunohistochemistry indicated that TAK1 is broadly expressed in both the developing otocyst and periotic mesenchyme at E12.5 but becomes more restricted to specific types of supporting cells as the organ of Corti matures. By P1, TAK1 immunolabeling is found in cells of the stria vascularis, hair cells, supporting cells, and Kölliker's organ. By P16, TAK1 labeling is limited to cochlear supporting cells. In the adult cochlea, TAK1 immunostaining is only present in the cytoplasm of Deiters' cells, pillar cells, inner phalangeal cells, and inner border cells, with no expression in any other cochlear cell types. While the role of TAK1 in the inner ear is unclear, TAK1 expression may be used as a novel marker for specific sub-populations of supporting cells.
authors.affiliation: Department of Communication Sciences and Disorders, Emerson College, Boston, MA, USA. Mark_Parker@meei.harvard.edu
authors.forename: Mark A
authors.initials: MA
authors.lastname: Parker
authors.forename: Kevin
authors.initials: K
authors.lastname: Jiang
authors.forename: Judith S
authors.initials: JS
authors.lastname: Kempfle
authors.forename: Kunio
authors.initials: K
authors.lastname: Mizutari
authors.forename: Caitlin L
authors.initials: CL
authors.lastname: Simmons
authors.forename: Rebecca
authors.initials: R
authors.lastname: Bieber
authors.forename: Joe
authors.initials: J
authors.lastname: Adams
authors.forename: Albert S B
authors.initials: AS
authors.lastname: Edge
mesh_terms: D000375:Aging / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D015415:Biomarkers / Q000378:metabolism; D003051:Cochlea / Q000166:cytology / Q000196:embryology / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D006198:Hair Cells, Auditory / Q000166:cytology / Q000378:metabolism*; D020930:MAP Kinase Kinase Kinases / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D008815:Mice, Inbred Strains; D023421:Models, Animal; D009925:Organ of Corti / Q000166:cytology / Q000378:metabolism*; D013316:Stria Vascularis / Q000166:cytology / Q000378:metabolism*; D000099151:MAP Kinase Kinase Kinase 7
chemical_list: D015415:Biomarkers; D020930:MAP Kinase Kinase Kinases; D000099151:MAP Kinase Kinase Kinase 7