Abstract
Purpose:
To identify the role of CXCL14 during chick cornea development. Chemokines, a family of small chemotactic cytokines, have recently gained interest for their ability to control processes such as cellular proliferation, migration, and differentiation during embryogenesis. Although, CXCL14 is expressed during embryonic development, its function has not yet been elucidated.
Methods:
We characterized the expression of CXCL14 during chick eye development by section in situ hybridization and immunohistochemistry. In loss-of-function studies, embryonic day (E) 1.5 embryos were injected with RCAS-CXCL14shRNA or control RCAS-GFP, and re-incubated for additional 6-8 days. Embryos were collected and examined for defects in cornea development by immunofluorescent staining of whole-mount and corneal sections.
Results:
During development, CXCL14 mRNA is expressed in the corneal stroma, iris, lens epithelium, and trigeminal ganglion. Similar patterns of expression were observed with anti-CXCL14 antibody. Knockdown of CXCL14 in vivo resulted in loss of CXCL14 expression and caused defects in cornea morphology and innervation. The corneas of E7 embryos treated with RCAS-CXCL14shRNA were relatively thinner compared to RCAS-GFP and untreated controls. In addition, nerve bundles projected further in the pericorneal nerve ring and the cornea was prematurely innervated in RCAS-CXCL14shRNA embryos. Furthermore, we observed extensive innervation of the iris in RCAS-CXCL14shRNA injected embryos at E9 that were not present in controls. Although CXCL14 is expressed in the trigeminal ganglion, we did not observe any defects in its morphology during gangliogenesis.
Conclusions:
Our results suggest a novel function of CXCL14 during cornea development and innervation. Since the receptor for CXCL14 is currently not known, we infer from these data that it might be either acting directly on neural crest cells and sensory nerves, or indirectly by affecting their response to environmental cues.
Keywords: 564 innervation: neural regulation •
490 cytokines/chemokines