Differential antiapoptotic effect of erythropoietin on undifferentiated and retinoic acid‐differentiated SH‐SY5Y cells

Abstract

Erythropoietin (Epo) is known to have a significant role in tissues outside the hematopoietic system. In this work, we investigated the function of Epo in cells of neuronal origin subjected to differentiation. Treatment of SH-SY5Y cells with all-trans-retinoic acid (atRA) generated differentiated neuron-like cells, observed by increased expression of neuronal markers and morphological changes. Exposure of undifferentiated cells to proapoptotic stimuli such as staurosporine, TNF-alpha, or hypoxia, significantly increased programmed cell death, which was prevented by previous treatment with Epo. In contrast, atRA-differentiated cultures showed cell resistance to apoptosis. No additional effect of Epo was detected in previously differentiated cells. The inhibition of the PI3K/Akt pathway by Ly294002 abrogated the protective effects induced by either Epo or atRA. The effect of atRA was mediated by an increased expression of Bcl-2 whereas the Epo treatment upregulated not only Bcl-2 but also Bcl-xL. This upregulation by Epo was not detected in atRA-differentiated cells, thus confirming the lack of the protective effect of Epo. As expected, assays with AG490, an inhibitor of Jak2, blocked the Epo action only in undifferentiated cells. This reduced neuroprotective function of Epo on SH-SY5Y differentiated cells could be explained at least in part by downregulation of the Epo receptor expression, which was observed in atRA-differentiated cells. This study shows differential cellular protection induced by Epo at two stages of SH-SY5Y differentiation. The results allow us to suggest that this differential cell behavior can be ascribed to the interaction between atRA and the signaling pathways mediated by Epo.

The erythropoietin receptor is a downstream effector of Klotho-induced cytoprotection

“…EPO has been shown to induce or enhance cells’ resistance to hypoxia, 49 oxidative stress, 50 cytokine-induced apoptosis, 49 radiation, 47 and cytotoxic agents. 47 To examine if EPO protects NRK cells from H 2 O 2 cytotoxicity, we treated NRK cells with different concentrations of EPO and measured LDH released into culture medium from NRK cells exposed to H 2 O 2 .…”

SMND-309 promotes neuron survival through the activation of the PI3K/Akt/CREB-signalling pathway

“…The system of cortical neuron cultures subjected to OGD/R has been widely used as an in vitro model to mimic the effects of ischaemia/ reperfusion injury in ischemic cerebrovascular disease (Zhang et al 2007). ATRA, a vitamin A derivative, plays an essential role in the development of the nervous system (Wenker et al 2010). ATRA is considered as an efficient inducer of neuronal differentiation in neuroblastoma cells; ATRA also induces these cells to obtain phenotypes, such as neurite outgrowth and morphological changes functionally and electrically similar to neurons (Sakane & Shidoji 2011;Wang et al 2014c).…”

Neuroprotective effects of mGluR II and III activators against staurosporine- and doxorubicin-induced cellular injury in SH-SY5Y cells: New evidence for a mechanism involving inhibition of AIF translocation

“…The lack of protection for most of the studied mGluR II/III ligands in RA-SH-SY5Y cells could be explained to some extent by biochemical changes evoked by RA during the differentiation process (e.g. MAPK/ERK1/2, PI3-K/Akt, MnSOD, Bcl-2) which could mask the protective effects of some of the tested mGluR II/III compounds (Cheung et al, 2009;Jantas et al, 2008;Lopes et al, 2010;Miloso et al, 2004;Presgraves et al, 2004;Wenker et al, 2010).…”