Abstract
Purpose :
While mice and chick studies have shown neural crest contributions to the ocular anterior segment, these contributions have not been demonstrated in zebrafish. Further, the craniofacial and ocular fates of neural crest cells and transcriptome differences between distinct neural crest subpopulations have not been determined. In the present study, we employed genetic manipulation technology to characterize neural crest contributions to the eye.
Methods :
Tg(sox10:CreERT2,myl7:GFP) and Tg(foxd3:CreERT2-GFP) were crossed with Tg(ubi:loxP-EGFP-loxP-mCherry) fish, and the embryos were treated with tamoxifen for 8-hour time periods between 10 and 42 hours postfertilization (hpf). Fish were raised to 90 dpf and sacrificed. Immunohistochemistry was used to detect mCherry expression. Heads of Tg(-4.7sox10:EGFP) and Tg(foxd3:GFP) embryos were collected at 48 hpf. Transcriptome analysis was performed on GFP-positive cells isolated with fluorescence-activated cell sorting (FACS).
Results :
Early (10-20 hpf) sox10-positive cells contributed to the dorsal and ventral iridocorneal angles, corneal stroma, and corneal endothelium but not to the cranial cartilages. In contrast, mid to late (20-42 hpf) sox10-positive cells showed minimal contribution to the ocular anterior segment but strong expression within the adult craniofacial cartilages. Indelibly marked foxd3-positive derivative cells were found in the sclera and corneal epithelium at all time points. Early foxd3-positive cells (10-20 hpf) contributed to the jaw, while late foxd3-positive cells (30-40 hpf) gave rise to corneal endothelial and stromal cells. Transcriptome analysis showed the differential expression of collagen genes associated with Stickler syndrome, retinoic acid signaling molecules, and keratin intermediate filaments between sox10 and foxd3-positive cell populations. Genes associated with anterior segment dysgenesis were found in both sox10 and foxd3-positive cell populations.
Conclusions :
Cranial neural crest cells contribute to the adult zebrafish anterior segment and craniofacial cartilage. The sox10 and foxd3 transcription factors expressed in early neural crest cells delineate distinct subpopulations with distinct transcriptomes and time-dependent ultimate cell fates.
This abstract was presented at the 2023 ARVO Annual Meeting, held in New Orleans, LA, April 23-27, 2023.