Identification of ADAMTS19 as a novel retinal factor involved in ocular growth regulation

Refractive errors are the most common ocular disorders and are a leading cause of visual impairment worldwide. Although ocular axial length is well established to be a major determinant of refractive errors, the molecular and cellular processes regulating ocular axial growth are poorly understood. Mutations in genes encoding the PRSS56 and MFRP are a major cause of nanophthalmos. Accordingly, mouse models with mutations in the genes encoding the retinal factor PRSS56 or MFRP, a gene predominantly localized in the retinal pigment epithelial (RPE) exhibit ocular axial length reduction and extreme hyperopia. However, the precise mechanisms underlying PRSS56- and MFRP-mediated ocular axial growth remain elusive. Here, we show that Adamts19 expression is significantly upregulated in retina of mice lacking either Prss56 or Mfrp. Using a combination of genetic approaches and mouse models, we show that while ADAMTS19 is not required for ocular growth during normal development, its inactivation exacerbates ocular axial length reduction in both Prss56 or Mfrp mutant mice. These results suggest that the upregulation of retinal Adamts19 expression is part of an adaptive molecular response to counteract impaired ocular growth. Using a complementary genetic approach. We further demonstrate that loss of PRSS56 or MFRP function prevents excessive ocular axial growth in a mouse model of developmental myopia caused by a null mutation in Irpb, demonstrating that ocular axial elongation in Irbp-/- mice is fully dependent on PRSS56 and MFRP functions. Collectively, our findings provide insight into the molecular network involved in ocular axial growth regulation and refractive development and support the notion that relay of the signal between the retina and RPE could be critical for promoting ocular axial elongation.