Non-erythropoietic erythropoietin derivatives protect from light-induced and genetic photoreceptor degeneration

Hum Mol Genet. 2011 Jun 1;20(11):2251-62. doi: 10.1093/hmg/ddr115. Epub 2011 Mar 19.

Abstract

Given the high genetic heterogeneity of inherited retinal degenerations (IRDs), a wide applicable treatment would be desirable to halt/slow progressive photoreceptor (PR) cell loss in a mutation-independent manner. In addition to its erythropoietic activity, erythropoietin (EPO) presents neurotrophic characteristics. We have previously shown that adeno-associated viral (AAV) vector-mediated systemic EPO delivery protects from PR degeneration. However, this is associated with an undesired hematocrit increase that could contribute to PR protection. Non-erythropoietic EPO derivatives (EPO-D) are available which allow us to dissect erythropoiesis's role in PR preservation and may be more versatile and safe than EPO as anti-apoptotic agents. We delivered in animal models of light-induced or genetic retinal degeneration either intramuscularly or subretinally AAV vectors encoding EPO or one of the three selected EPO-D: the mutant S100E, the helix A- and B-derived EPO-mimetic peptides. We observed that (i) systemic expression of S100E induces a significantly lower hematocrit increase than EPO and provides similar protection from PR degeneration, and (ii) intraocular expression of EPO-D protects PR from degeneration in the absence of significant hematocrit increase. On the basis of this, we conclude that erythropoiesis is not required for EPO-mediated PR protection. However, the lower efficacy observed when EPO or S100E is expressed intraocularly rather than systemically suggests that hormone systemic effects contribute to PR protection. Unlike S100E, EPO-mimetic peptides preserve PR only when given locally, suggesting that different EPO-D have a different potency or mode of action. In conclusion, our data show that subretinal delivery of AAV vectors encoding EPO-D protects from light-induced and genetic PR degeneration.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / genetics
  • Adaptor Proteins, Signal Transducing / metabolism
  • Animals
  • Dependovirus
  • Erythropoiesis
  • Erythropoietin / genetics
  • Erythropoietin / pharmacology*
  • Gene Transfer Techniques
  • Genetic Vectors
  • Hematocrit
  • Intermediate Filament Proteins / genetics
  • Intermediate Filament Proteins / metabolism
  • Light / adverse effects*
  • Membrane Glycoproteins / genetics
  • Membrane Glycoproteins / metabolism
  • Mice
  • Mice, Inbred BALB C
  • Mice, Inbred C57BL
  • Mice, Inbred CBA
  • Mice, Knockout
  • Models, Animal
  • Mutation
  • Nerve Tissue Proteins / genetics
  • Nerve Tissue Proteins / metabolism
  • Peripherins
  • Photoreceptor Cells, Vertebrate / pathology*
  • Rats
  • Rats, Inbred Lew
  • Retinal Degeneration / genetics
  • Retinal Degeneration / therapy*

Substances

  • Adaptor Proteins, Signal Transducing
  • Aipl1 protein, mouse
  • Intermediate Filament Proteins
  • Membrane Glycoproteins
  • Nerve Tissue Proteins
  • Peripherins
  • Erythropoietin