Abstract
Background:
Sexual differences in the biology of human stem cells are increasingly recognized to influence their proliferation, differentiation and maturation. Especially in neurodegenerative diseases such as Alzheimers disease (AD), Parkinson's disease (PD) or ischemic stroke, sex is a key player for disease progression and recovery of damaged tissue. Recently, the glycoprotein hormone erythropoietin (EPO) has been implicated as a regulator of neuronal differentiation and maturation in female rats.
Methods:
In this study, we used adult human neural crest-derived stem cells (NCSCs) as a model system for exploring potential sex specific effects of EPO on human neuronal differentiation. We started with expression validation of the specific EPO receptor (EPOR) by performing PCR analysis in the NCSCs. Next, EPO mediated activation of nuclear factor-κB (NF-κB) via Immunocytochemistry (ICC) was performed, followed by investigating the sex-specific effects of EPO on neuronal differentiation by determining morphological changes in axonal growth and neurite formation accompanied by ICC.
Results:
Undifferentiated male and female NCSCs showed a ubiquitous expression of the EPO receptor (EPOR). EPO treatment resulted in a statistically profound (male p = 0.0022, female p = 0.0012) nuclear translocation of NF-κB RELA in undifferentiated NCSCs of both sexes. But after one week of neuronal differentiation, we could show a highly significant (p = 0,0079) increase of nuclear NF-κB RELA in females only. In contrast, we observed a strong decrease (p = 0,0022) of RELA activation in male neuronal progenitors. Extending the view on the role of sex during human neuronal differentiation, here we demonstrate a significant increase of axon lengths in female NCSCs-derived neurons upon EPO-treatment (+ EPO: 167,73 (SD = 41,66) µm, w/o EPO: 77,68 (SD = 18,31) µm) compared to their male counterparts (+ EPO: 68,37 (SD = 11,97) µm, w/o EPO: 70,23 (SD = 12,89) µm).
Conclusion:
Our present findings therefore show for the first time an EPO-driven sexual dimorphism in neuronal differentiation of human neural-crest derived stem cells and emphasize sex-specific variability as a crucial parameter in stem cell biology and for treating neurodegenerative diseases.
Keywords:
Adult neural-crest-derived stem cells; Axon length; Erythropoietin; Neuronal differentiation; Neuronal morphology and plasticity; Sexual dimorphism.