TGFβ signaling inhibits goblet cell differentiation via SPDEF in conjunctival epithelium.
The ocular surface epithelia, including the stratified but non-keratinized corneal, limbal and conjunctival epithelium, in concert with the epidermal keratinized eyelid epithelium, function together to maintain eye health and vision. Abnormalities in cellular proliferation or differentiation in any of these surface epithelia are central in the pathogenesis of many ocular surface disorders. Goblet cells are important secretory cell components of various epithelia, including the conjunctiva; however, mechanisms that regulate goblet cell differentiation in the conjunctiva are not well understood. Herein, we report that conditional deletion of transforming growth factor β receptor II (Tgfbr2) in keratin 14-positive stratified epithelia causes ocular surface epithelial hyperplasia and conjunctival goblet cell expansion that invaginates into the subconjunctival stroma in the mouse eye. We found that, in the absence of an external phenotype, the ocular surface epithelium develops properly, but young mice displayed conjunctival goblet cell expansion, demonstrating that TGFβ signaling is required for normal restriction of goblet cells within the conjunctiva. We observed increased expression of SAM-pointed domain containing ETS transcription factor (SPDEF) in stratified conjunctival epithelial cells in Tgfbr2 cKO mice, suggesting that TGFβ restricted goblet cell differentiation directly by repressing Spdef transcription. Gain of function of Spdef in keratin 14-positive epithelia resulted in the ectopic formation of goblet cells in the eyelid and peripheral cornea in adult mice. We found that Smad3 bound two distinct sites on the Spdef promoter and that treatment of keratin 14-positive cells with TGFβ inhibited SPDEF activation, thereby identifying a novel mechanistic role for TGFβ in regulating goblet cell differentiation.
Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, 3333 Burnett Avenue, Cincinnati, OH 45229, USA.
Heather A
HA
McCauley
Department of Ophthalmology, Edith J. Crawley Vision Research Center, College of Medicine, University of Cincinnati, Cincinnati, OH 45267, USA.
Chia-Yang
CY
Liu
Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, 3333 Burnett Avenue, Cincinnati, OH 45229, USA.
Aria C
AC
Attia
Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, 3333 Burnett Avenue, Cincinnati, OH 45229, USA Pathology and Laboratory Medicine, Cincinnati Children's Hospital Medical Center and University of Cincinnati, 3333 Burnett Avenue, Cincinnati, OH 45229, USA.
Kathryn A
KA
Wikenheiser-Brokamp
Department of Ophthalmology, Edith J. Crawley Vision Research Center, College of Medicine, University of Cincinnati, Cincinnati, OH 45267, USA.
Yujin
Y
Zhang
Division of Pulmonary Biology, Cincinnati Children's Hospital Medical Center, 3333 Burnett Avenue, Cincinnati, OH 45229, USA.
Jeffrey A
JA
Whitsett
Division of Developmental Biology, Cincinnati Children's Hospital Medical Center, 3333 Burnett Avenue, Cincinnati, OH 45229, USA geraldine.guasch@cchmc.org.
Géraldine
G
Guasch
D000818:Animals; D002454:Cell Differentiation / Q000502:physiology*; D047369:Chromatin Immunoprecipitation; D003228:Conjunctiva / Q000166:cytology / Q000254:growth & development*; D005434:Flow Cytometry; D020397:Goblet Cells / Q000502:physiology*; D006652:Histological Techniques; D053547:Keratin-14 / Q000378:metabolism; D061346:Laser Capture Microdissection; D008156:Luciferases; D051379:Mice; D018345:Mice, Knockout; D017346:Protein Serine-Threonine Kinases / Q000235:genetics / Q000378:metabolism*; D050783:Proto-Oncogene Proteins c-ets / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D000077294:Receptor, Transforming Growth Factor-beta Type II; D018125:Receptors, Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D051900:Smad3 Protein / Q000378:metabolism; D016212:Transforming Growth Factor beta / Q000378:metabolism*
D053547:Keratin-14; C507446:Krt14 protein, mouse; D050783:Proto-Oncogene Proteins c-ets; D018125:Receptors, Transforming Growth Factor beta; D051900:Smad3 Protein; C497791:Smad3 protein, mouse; C519908:Spdef protein, mouse; D016212:Transforming Growth Factor beta; D008156:Luciferases; D017346:Protein Serine-Threonine Kinases; D000077294:Receptor, Transforming Growth Factor-beta Type II
Conjunctiva; Differentiation; Goblet cells; Mouse; SPDEF; TGFβ signaling