RNA-Seq data of mouse retina, retinal pigment epithelium and cones

The differentiation of cone photoreceptors, which mediate daylight vision and color vision, depends critically upon thyroid hormone.However, the route of access of blood-borne thyroid hormone to cones is undefined because cones reside behind the blood-retina barrier. This study uses genetic manipulation of a membrane transporter for thyroid hormone (Mct8) in mouse models to show a role for the retinal pigment epithelium (RPE), which forms the outer blood-retina barrier, in the control of cone differentiation.The results suggest a paracrine-like mechanism promotes thyroid hormone-mediated cone differentiation. The findings suggest that in addition to the transport of essential solutes and support of photoreceptor homeostasis, the RPE controls hormonal signaling required for cone differentiation.