Abstract
Purpose: :
To investigate the role that mammalian target of rapamycin (mTOR) plays in the production of collagen by human retinal pigment epithelial (hRPE) cells in vivo and in vitro.
Methods: :
In vitro cultures of the hRPE cell line D407 were treated with three mTOR specific small interfering RNAs. Real time reverse transcriptase polymerase chain reaction was performed to investigate collagen mRNA expression. Enzyme-linked immunosorbent assay (ELISA) and immunocytochemical analyses were performed to investigate extracellular and intracellular production of collagens type I, III and IV. The effect of the mTOR specific siRNA on collagen production in vivo was tested using a rabbit model in which proliferative vitreoretinopathy (PVR) was induced by the injection of hRPE cells.
Results: :
Small interfering RNA treatment decreased mTOR expression by about 82% and resulted in a significant decrease in collagen mRNA expression, and a parallel decrease in extracellular and intracellular production of type I, III and IV collagen. Furthermore, knock down of mTOR significantly reduced the production of collagen in the in vivo PVR model.
Conclusions: :
mTOR plays an important role in regulating the expression of collagen type I, III and IV collagen in hRPE cells in vitro and in vivo. Because collagen overproduction is a main feature of PVR, identification of mTOR as a critical mediator of its regulation may provide a suitable target for gene therapy.
Keywords: proliferative vitreoretinopathy • retinal pigment epithelium • RNAi