title: TRPV4 Regulates Tight Junctions and Affects Differentiation in a Cell Culture Model of the Corneal Epithelium.
abstract: TRPV4 (transient receptor potential vanilloid 4) is a cation channel activated by hypotonicity, moderate heat, or shear stress. We describe the expression of TRPV4 during the differentiation of a corneal epithelial cell model, RCE1(5T5) cells. TRPV4 is a late differentiation feature that is concentrated in the apical membrane of the outmost cell layer of the stratified epithelia. Ca2+imaging experiments showed that TRPV4 activation with GSK1016790A produced an influx of calcium that was blunted by the specific TRPV4 blocker RN-1734. We analyzed the involvement of TRPV4 in RCE1(5T5) epithelial differentiation by measuring the development of transepithelial electrical resistance (TER) as an indicator of the tight junction (TJ) assembly. We showed that TRPV4 activity was necessary to establish the TJ. In differentiated epithelia, activation of TRPV4 increases the TER and the accumulation of claudin-4 in cell-cell contacts. Epidermal Growth Factor (EGF) up-regulates the TER of corneal epithelial cultures, and we show here that TRPV4 activation mimicked this EGF effect. Conversely, TRPV4 inhibition or knock down by specific shRNA prevented the increase in TER. Moreover, TRPP2, an EGF-activated channel that forms heteromeric complexes with TRPV4, is also concentrated in the outmost cell layer of differentiated RCE1(5T5) sheets. This suggests that the EGF regulation of the TJ may involve a heterotetrameric TRPV4-TRPP2 channel. These results demonstrated TRPV4 activity was necessary for the correct establishment of TJ in corneal epithelia and as well as the regulation of both the barrier function of TJ and its ability to respond to EGF. J. Cell. Physiol. 232: 1794-1807, 2017. © 2016 Wiley Periodicals, Inc.
authors.affiliation: Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del IPN, Ciudad de México, México.
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Martínez-Rendón
authors.affiliation: Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN, Ciudad de México, México.
authors.forename: Erika
authors.initials: E
authors.lastname: Sánchez-Guzmán
authors.affiliation: Departamento de Bioquímica, Centro de Investigación y de Estudios Avanzados del IPN, Ciudad de México, México.
authors.forename: Angélica
authors.initials: A
authors.lastname: Rueda
authors.affiliation: Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del IPN, Ciudad de México, México.
authors.forename: James
authors.initials: J
authors.lastname: González
authors.affiliation: Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN, Ciudad de México, México.
authors.forename: Rosario
authors.initials: R
authors.lastname: Gulias-Cañizo
authors.affiliation: Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del IPN, Ciudad de México, México.
authors.forename: Guillermo
authors.initials: G
authors.lastname: Aquino-Jarquín
authors.affiliation: Departamento de Biología Celular, Centro de Investigación y de Estudios Avanzados del IPN, Ciudad de México, México.
authors.forename: Federico
authors.initials: F
authors.lastname: Castro-Muñozledo
authors.affiliation: Departamento de Fisiología, Biofísica y Neurociencias, Centro de Investigación y de Estudios Avanzados del IPN, Ciudad de México, México.
authors.forename: Refugio
authors.initials: R
authors.lastname: García-Villegas
mesh_terms: D016475:3T3 Cells; D000818:Animals; D002118:Calcium / Q000378:metabolism; D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D062506:Claudin-4 / Q000378:metabolism; D017097:Electric Impedance; D004815:Epidermal Growth Factor / Q000494:pharmacology; D019573:Epithelium, Corneal / Q000166:cytology*; D015640:Ion Channel Gating / Q000187:drug effects; D051379:Mice; D008954:Models, Biological; D021381:Protein Transport / Q000187:drug effects; D011817:Rabbits; D013347:Subcellular Fractions / Q000378:metabolism; D050916:TRPV Cation Channels / Q000378:metabolism*; D019108:Tight Junctions / Q000187:drug effects / Q000378:metabolism*; D013997:Time Factors
chemical_list: D062506:Claudin-4; D050916:TRPV Cation Channels; D004815:Epidermal Growth Factor; D002118:Calcium