EphB4 Regulates Self-Renewal, Proliferation and Neuronal Differentiation of Human Embryonic Neural Stem Cells in Vitro

Abstract

Background/Aims: EphB4 belongs to the largest family of Eph receptor tyrosine kinases. It contributes to a variety of pathological progresses of cancer malignancy. However, little is known about its role in neural stem cells (NSCs). This study examined whether EphB4 is required for proliferation and differentiation of human embryonic neural stem cells (hNSCs) in vitro. Methods: We up- and down-regulated EphB4 expression in hNSCs using lentiviral over-expression and shRNA knockdown constructs and then investigated the influence of EphB4 on the properties of hNSCs. Results: Our results show that shRNA-mediated EphB4 reduction profoundly impaired hNSCs self-renewal and proliferation. Furthermore, detection of differentiation revealed that knockdown of EphB4 inhibited hNSCs differentiation towards a neuronal lineage and promoted hNSCs differentiation to glial cells. In contrast, EphB4 overexpression promoted hNSCs self-renewal and proliferation, further induced hNSCs differentiation towards a neuronal lineage and inhibited hNSCs differentiation to glial cells. Moreover, we found that EphB4 regulates cell proliferation mediated by the Abl-CyclinD1 pathway. Conclusion: These studies provide strong evidence that fine tuning of EphB4 expression is crucial for the proliferation and neuronal differentiation of hNSCs, suggesting that EphB4 might be an interesting target for overcoming some of the therapeutic limitations of neuronal loss in brain diseases.

Alternative Erythropoietin Receptors in the Nervous System

“…EphB4 is expressed in the mammalian nervous system and ephrin-B2/EphB4 signaling has been demonstrated to regulate adult neurogenesis and its balance with gliogenesis in the subgranular zone of the hippocampus [ 177 , 186 ]. EphB4 expressed by neural stem cells is activated by direct contact with ephrin-B2 expressing astrocytes.…”

“…EphB4 expressed by neural stem cells is activated by direct contact with ephrin-B2 expressing astrocytes. This interaction stimulates self-renewal of and proliferation of neural stem cells and differentiation towards the neuronal lineage [ 177 , 186 ]. Indicating its role in synaptic function, ephrin-B2 knock-out in mouse hippocampus attenuated long term potentiation of synaptic transmission (LTP) following high-frequency synaptic activation [ 187 ].…”

Enabling Tumor Growth and Progression: Recent Progress in Unraveling the Functions of ABL Kinases in Solid Tumor Cells

“…Similarly, overexpression of the Ras effector protein Rin1, an ABL1 activator, suppresses MDA-MB-231 invasiveness, and expression of a mutant form that inhibits ABL1 function, cannot suppress invasion [127]. These results contrast with reports showing that silencing ABL1/ABL2 prevents MDA-MB-231 cell invasion [87, 81, 128, 56], and EphB4 activation of ABL kinases in human embryonic neural stem cells promotes self-renewal and proliferation [129]. These data are consistent with the notion that ABL kinases promote proliferation/invasion downstream of factors that induce these processes and inhibit proliferation/invasion in response to molecules that oppose these processes, thus, likely integrating the signals [69].…”

Keratan sulfate, a complex glycosaminoglycan with unique functional capability

“…This induces neural cell proliferation and terminal differentiation ( Chirivella et al 2017 ). Microarray studies with corneal KS demonstrate that it also interacts with the Ephrin 4 receptor and may promote neuronal cell proliferation and differentiation through Ephrin tyrosine kinase activity ( Liu et al 2017 ).…”