Transplantation of Brain–Derived Neurotrophic Factor Transduced Iris Pigment Epithelial Cell and Aberrant Expression of Its Receptor Isoforms in the Retina

Abstract

Abstract: : Purpose: To examine the expression of brain–derived neurotrophic factor (BDNF) receptor TrkB and its isoforms in the retina after BDNF–transduced iris pigment epithelial cell (IPE) transplantation. Methods: Rat IPE was prepared as we reported previously and BDNF cDNA was transduced by lipofection (BDNF–IPE) and selected by appropriate antibiotics. We also constructed adeno–associated virus vector (AAV) with BDNF (AAV–BDNF) and transduced on rat IPE (AAV–BDNF–IPE). We used several concentration of AAV–BDNF. We transplanted AAV–BDNF–IPE to rat subretinal space and performed real time quantitative polymerase chain reaction (RT–PCR), western blotting analysis, and immunohistochemistry for TrkB one week after transplantation. The primers were designed in order to amplify both complete and truncated (TrkB–T1) type TrkB. Results: Cultured rat IPE showed low expression of TrkB when compared to that of retina, but was suspected to be induced the expression by BDNF transduction. Normal rat retina expressed more complete type TrkB than that of TrkB–T1 in standard light cycle. However, the expression level was reversed and TrkB–T1 was expressed more than that of complete type when BDNF–IPE or AAV–BDNF–IPE was transplanted. The expression of TrkB–T1 was suspected to be influenced by AAV–BDNF concentration. Conclusions: BDNF–IPE or AAV–BDNF–IPE transplantation will induce aberrant expression of TrkB isoforms in the retina.

Keywords: transplantation • gene transfer/gene therapy • neuroprotection