Abstract
Purpose In Retinopathy of Prematurity (ROP), infants often have incomplete vascularization, affecting the temporal region. A factor expressed in this region during retinal development is the T-box factor, Tbx3, which has not been studied in the mammalian eye. The purpose of this study was to determine if Tbx3 is required during eye formation for retinal angiogenesis.
Methods Conditional removal of Tbx3 from both retinal progenitors and astrocytes was done using the optic cup-Cre recombinase driver, BAC-Dkk3-CRE and analyzed using standard immunohistochemical techniques.
Results With Tbx3 loss, the retinas were hypovascular, as seen in patients with ROP and Familial Exudative Vitreoretinopathy (FEVR). Retinal vasculature failed to form the stereotypic tri-layered plexus in the dorsal-temporal region. Astrocyte precursors were reduced in number and failed to form a lattice at the dorsal-temporal edge. We next examined retinal ganglion cells, as they have been shown to play a critical role in retinal angiogenesis. We found that melanopsin expression and Islet1/2-positive retinal ganglion cells were reduced in the dorsal half of the retina. In previous studies, loss of melanopsin has been linked to hyaloid artery persistence, which we also observed in the Tbx3 cKO retina, as well as in infants with ROP or FEVR.
Conclusions Together, these results show that TBX3 is required for normal mammalian eye formation for the first time. This potentially provides a new genetic model for retinal hypovascular diseases.
Competing Interest Statement
The authors have declared no competing interest.
Footnotes
Funding: This study was supported by the National Institutes of Health (R21 EY029114 to A.S.V; R01 EY012676 to W.J.B; R21 EY030654 to M.E.Z; R01 EY024373 to S.F.), and grants to the Ophthalmology and Visual Sciences Department from Research to Prevent Blindness (Unrestricted Award) and the District 20-Y Lions Club.
Commercial relationship disclosures: none.
In this new version, we have edited the abstract, reduced the text length and added supplemental data files. We have also added data showing endothelial cell staining with our astrocyte markers in cKO retinas (Figure 5) to clarify the interaction between these two cell types. Author Dr. Sabine Fuhrmann, who was seminal in establishing this project, was also added.