Purpose: To characterize ocular disease in HIF-2alpha-null mice.
Methods: Histologic, electroretinographic (ERG), and molecular studies were performed on samples obtained from age- and gender-matched HIF-2alpha-null (HIF-2alpha-KO), HIF-2alpha-heterozygous (HIF-2alpha-HET), and wild-type (WT) littermate mice.
Results: HIF-2alpha-KO mice exhibited marked thinning of the retina and abnormal retinal vasculature. The pathologic changes in HIF-2alpha-KO mice were associated with a virtual absence of postreceptor function. The expression of a surrogate marker for HIF-2alpha mRNA localized to vascular endothelial, amacrine, and retinal pigment epithelial (RPE) cells. Several HIF-2alpha target genes involved in angiogenesis, retinal protection, and stress responses have altered expression patterns in HIF-2alpha-KO retinas.
Conclusions: HIF-2alpha-KO mice exhibit marked retinopathy consistent with complete loss of vision by 1 month of age. Impaired HIF-2alpha signaling in HIF-2alpha-KO mice likely produces functional deficits in cell types in which HIF-2alpha normally is expressed, ultimately resulting in retinopathy. Future studies will address whether the molecular abnormalities described in this study are directly responsible for the retinal disease in HIF-2alpha-KO mice.