Genetic determinants of hyaloid and retinal vasculature in zebrafish.
BACKGROUND
The retinal vasculature is a capillary network of blood vessels that nourishes the inner retina of most mammals. Developmental abnormalities or microvascular complications in the retinal vasculature result in severe human eye diseases that lead to blindness. To exploit the advantages of zebrafish for genetic, developmental and pharmacological studies of retinal vasculature, we characterised the intraocular vasculature in zebrafish.


RESULTS
We show a detailed morphological and developmental analysis of the retinal blood supply in zebrafish. Similar to the transient hyaloid vasculature in mammalian embryos, vessels are first found attached to the zebrafish lens at 2.5 days post fertilisation. These vessels progressively lose contact with the lens and by 30 days post fertilisation adhere to the inner limiting membrane of the juvenile retina. Ultrastructure analysis shows these vessels to exhibit distinctive hallmarks of mammalian retinal vasculature. For example, smooth muscle actin-expressing pericytes are ensheathed by the basal lamina of the blood vessel, and vesicle vacuolar organelles (VVO), subcellular mediators of vessel-retinal nourishment, are present. Finally, we identify 9 genes with cell membrane, extracellular matrix and unknown identity that are necessary for zebrafish hyaloid and retinal vasculature development.


CONCLUSIONS
Zebrafish have a retinal blood supply with a characteristic developmental and adult morphology. Abnormalities of these intraocular vessels are easily observed, enabling application of genetic and chemical approaches in zebrafish to identify molecular regulators of hyaloid and retinal vasculature in development and disease.
Alvarez
Yolanda
Y
UCD School of Biomolecular, and Biomedical Sciences, University College Dublin, Dublin 4, Ireland. yolanda.alvarez@ucd.ie
Cederlund
Maria L
ML
Cottell
David C
DC
Bill
Brent R
BR
Ekker
Stephen C
SC
Torres-Vazquez
Jesus
J
Weinstein
Brant M
BM
Hyde
David R
DR
Vihtelic
Thomas S
TS
Kennedy
Breandan N
BN
D000818:Animals; D002829:Choroid / Q000098:blood supply* / Q000254:growth & development; D003285:Contractile Proteins / Q000235:genetics; D004625:Embryo, Nonmammalian; D016326:Extracellular Matrix Proteins / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D007150:Immunohistochemistry; D018919:Neovascularization, Physiologic / Q000235:genetics; D009898:Optic Disk / Q000098:blood supply; D000072260:RNA Splicing Factors; D011956:Receptors, Cell Surface / Q000235:genetics; D015861:Retinal Neovascularization / Q000235:genetics; D012171:Retinal Vessels / Q000254:growth & development*; D013045:Species Specificity; D015027:Zebrafish / Q000235:genetics* / Q000254:growth & development*; D029961:Zebrafish Proteins / Q000235:genetics
D003285:Contractile Proteins; D016326:Extracellular Matrix Proteins; D000072260:RNA Splicing Factors; D011956:Receptors, Cell Surface; D029961:Zebrafish Proteins; C016598:microfibrillar protein; C488979:plxnd1 protein, zebrafish