Abstract
Purpose::
To determine the cell lineages of ocular surface tissues, e.g., corneal endothelium, keratocytes, and stromal cells in iris, ciliary body, trabecular meshwork and eyelids.
Methods::
During embryonic development of transgenic mouse lines, Wnt1-Cre transgene is transiently activated between E10.5 through E12.5, whereas Kera-Cre transgene is activated at E13.5 and afterwards, by migrating periocular mesenchymal cells of neural crest origin. Bitransgenic Kera-Cre/ZEG and Wnt1-Cre/ZEG mice were prepared by cross breeding Kera-Cre and Wnt1-Cre mice with ZEG reporter mice, respectively. The distribution of EGFP positive, neural crest derived migrating periocular mesenchymal cells were determined in 100-150 µm thick vibratome sections of ocular surface tissues taken at various times during development using a ZEISS 510 Meta LSM confocal microscope.
Results::
In cornea of Wnt1-Cre/ZEG bitransgenic mice both endothelial cells, keratocytes and nerves were EGFP positive, whereas in Kera-Cre/ZEG mice only keratocytes were EGFP positive. In eyelids, EGFP positive stromal cells were found surrounding hair follicles at the bulge-region and hair papilla. EGFP positive stromal cells also surrounded Meibomian gland ducts and acini of Kera-Cre/ ZEG mice. EGFP positive cells were also found in stromas of iris, ciliary body, and trabecular meshwork of Kera-Cre/ZEG mice.
Conclusions::
The expression of EGFP by the corneal endothelium in the Wnt1-Cre/ZEG but not the Kera-Cre/ZEG mice are consistent with the notion that that there are two waves of mesenchymal cell migration during mouse corneal morphogenesis. In addition, these migrating periocular mesenchymal cells also contribute to the morphogenesis of the eyelash, Meibomian glands and stromas of eyelids, iris, ciliary body, and trabecular meshwork.
Keywords: development • transgenics/knock-outs • cornea: stroma and keratocytes