title: SRC tyrosine kinases regulate neuronal differentiation of mouse embryonic stem cells via modulation of voltage-gated sodium channel activity.
abstract: Voltage-gated Na(+) channel activity is vital for the proper function of excitable cells and has been indicated in nervous system development. Meanwhile, the Src family of non-receptor tyrosine kinases (SFKs) has been implicated in the regulation of Na(+) channel activity. The present investigation tests the hypothesis that Src family kinases influence neuronal differentiation via a chronic regulation of Na(+) channel functionality. In cultured mouse embryonic stem (ES) cells undergoing neural induction and terminal neuronal differentiation, SFKs showed distinct stage-specific expression patterns during the differentiation process. ES cell-derived neuronal cells expressed multiple voltage-gated Na(+) channel proteins (Nav) and underwent a gradual increase in Na(+) channel activity. While acute inhibition of SFKs using the Src family inhibitor PP2 suppressed the Na(+) current, chronic inhibition of SFKs during early neuronal differentiation of ES cells did not change Nav expression. However, a long-lasting block of SFK significantly altered electrophysiological properties of the Na(+) channels, shown as a right shift of the current-voltage relationship of the Na(+) channels, and reduced the amplitude of Na(+) currents recorded in drug-free solutions. Immunocytochemical staining of differentiated cells subjected to the chronic exposure of a SFK inhibitor, or the Na(+) channel blocker tetrodotoxin, showed no changes in the number of NeuN-positive cells; however, both treatments significantly hindered neurite outgrowth. These findings suggest that SFKs not only modulate the Na(+) channel activation acutely, but the tonic activity of SFKs is also critical for normal development of functional Na(+) channels and neuronal differentiation or maturation of ES cells.
authors.affiliation: Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, SC, 29425, USA.
authors.forename: Kevin R
authors.initials: KR
authors.lastname: Francis
authors.forename: Ling
authors.initials: L
authors.lastname: Wei
authors.forename: Shan Ping
authors.initials: SP
authors.lastname: Yu
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D002460:Cell Line; D053595:Embryonic Stem Cells / Q000166:cytology* / Q000201:enzymology / Q000378:metabolism; D015640:Ion Channel Gating; D051379:Mice; D009474:Neurons / Q000166:cytology* / Q000502:physiology; D018408:Patch-Clamp Techniques; D015222:Sodium Channels / Q000378:metabolism*; D019061:src-Family Kinases / Q000378:metabolism*
chemical_list: D015222:Sodium Channels; D019061:src-Family Kinases