Erythropoietin enhances cell proliferation and survival of human fetal neuronal progenitors in normoxia.

Extensive data reporting the neurogenerative, neuroprotective and neuroregenerative potential of erythropoietin (EPO), mainly on RNA level, can be found in the literature. However, there is still a poor knowledge on the response of neuronal progenitor cells (NPC) upon stimulation with EPO in terms of the protein species involved. Herein, the effect of EPO on the proliferation of human mesencephalic NPC (hmNPC) under normoxia is monitored using cellular assays and proteomic analysis (two-dimensional gel electrophoresis and MALDI-TOF mass spectrometry). The administration of EPO increased the proliferation of hmNPC within 4 days after application. It positively influenced the cell-cycle progression by affecting the G2 phase of the cell cycle. A proteomic analysis of the protein expression in hmNPC cultures 4 days after EPO treatment identified 8 proteins differentially expressed in EPO-treated cultures. It is likely that one or more of the identified proteins are involved in cellular pathways that promote cell proliferation and differentiation of hmNPC under normoxia. Their further characterization could provide cellular targets for the development of new therapeutic agents to treat CNS injury. Moreover, as EPO signaling is hypoxia-inducible, our findings may also indicate the beneficial effect of EPO to mimic hypoxia, while bypassing its negative effects, to culture human fetal midbrain-derived progenitor cells.

Proteomic analysis to display the effect of low doses of erythropoietin on rat liver regeneration.

AIMS: Several groups found different impact of erythropoietin (EPO) on liver regeneration. Both pro-proliferative as well as anti-proliferative and non-proliferative activities have been reported using high dosage of EPO. Systemic administration of high doses of this cytokine is a clinical concern due to risk of thrombosis. Herein, we applied EPO in low dosages and investigated whether it can stimulate liver regeneration after liver resection. MAIN METHODS: Parameters of liver regeneration were assessed 3 days after 70% hepatectomy by means of immunochemistry and proteomics. EPO was given twice in low dosages (200 and 600 IU/kg BW). KEY FINDINGS: We showed that EPO facilitated hepatic regeneration in rats. Enhanced hepatocyte proliferation (Ki67, BrdU-positive cells) was observed in all EPO-treated groups. By performing Differential Proteomic analysis, we identified two proteins which resulted sensitive to EPO treatment after hepatectomy: Peroxiredoxin-1 and glutathione S-transferase Mu 1. SIGNIFICANCE: Based on our results, low doses of rhEPO increase the hepatic regenerative capacity after partial hepatectomy in rats by enhancing hepatocyte proliferation and acting on antioxidant enzymes. Both proteins identified by proteomic analysis have not previously been associated with liver regeneration and will aid in the understanding of EPO's regenerative response having clinical implications to treat liver failure.