Tehran University of Medical Sciences Iranian Journal of Public Health 2251-6085 51 7 2022 07 09 1658 1666 Bahar Safdari Ocular Tissue Engineering Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran Mozhgan Rezaei-Kanavi Ocular Tissue Engineering Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran Mohammad Amir Mishan Ocular Tissue Engineering Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran Hamid Ahmadieh Ophthalmic Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran Zahra-soheila Soheili Department of Molecular Medicine, National Institute of Genetic Engineering and Biotechnology, Tehran, Iran Iman Slahshouri Far Department of Biology, Science and Research Branch, Islamic Azad University, Tehran, Iran Fatemeh Suri Ophthalmic Research Center, Research Institute for Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran 2021 03 17 2021 06 21 Background: Nogo-A, a myelin-associated inhibitor for neurite outgrowth, has important role in visual system development. Trans-differentiation ability of human amniotic fluid (HAF) on human retinal pigment epithelial cells (hRPEs) towards neural progenitor cells has been observed in several studies. We aimed to investigate the expression of NOGO-A gene and its receptors as a marker of neural differentiation in HAF-treated hRPE cells. Methods: hRPE cells were cultivated and immune characterized via RPE65 and cytokeratin 8/18 protein markers. Also, the cytotoxicity effect of 30% HAF on hRPE cells was evaluated using ELISA cell death assay. Finally, expression of NOGO-A and its receptors, RTN4R and LINGO1 was evaluated in the cells treated with HAF in comparison with FBS-treated cells using quantitative real-time PCR. Results: Harvested cells showed immunoreactivity for cytokeratin 8/18 and RPE65, confirming the hRPE cell identity. Besides, HAF had no cytotoxic effect on hRPE cells compared with FBS-treated cells. Results showed that NOGO-A and its receptors were expressed in cultured hRPE cells. Besides, comparative gene expression analysis revealed significant increased expression of the investigated genes in HAF-treated hRPE cells compared to FBS-treated cells. Conclusion: Augmented expression of NOGO-A and its receptors can support neural differentiation of hRPE when the cells are treated with HAF. Our outcomes provide more evidences on the trans-differentiation ability of HAF on hRPE cells into neural progenitors and retinal neural cells, but further studies are needed to elucidate the exact mechanism. https://ijph.tums.ac.ir/index.php/ijph/article/view/24221 https://ijph.tums.ac.ir/index.php/ijph/article/download/24221/7668