title: T-type Ca2+ channels in mouse embryonic stem cells: modulation during cell cycle and contribution to self-renewal.
abstract: Ion channels participate in cell homeostasis and are involved in the regulation of proliferation and differentiation in several cell types; however, their presence and function in embryonic stem (ES) cells are poorly studied. We have investigated the existence of voltage-dependent inward currents in mouse ES cells and their ability to modulate proliferation and self-renewal. Patch-clamped ES cells had inactivating tetrodotoxin (TTX)-sensitive Na(+) currents as well as transient Ca(2+) currents abolished by the external application of Ni(2+). Biophysical and pharmacological data indicated that the Ca(2+) current is predominantly mediated by T-type (Ca(v)3.2) channels. The number of cells expressing T-type channels and Ca(v)3.2 mRNA levels increased at the G1/S transition of the cell cycle. TTX had no effect on ES cell proliferation. However, blockade of T-type Ca(2+) currents with Ni(2+) induced a decrease in proliferation and alkaline phosphatase positive colonies as well as reduced expression of Oct3/4 and Nanog, all indicative of loss in self-renewal capacity. Decreased alkaline phosphatase and Oct3/4 expression were also observed in cells subjected to small interfering RNA-induced knockdown for T-type (Ca(v)3.2) Ca(2+) channels, thus partially recapitulating the pharmacological effects on self-renewal. These results indicate that Ca(v)3.2 channel expression in ES cells is modulated along the cell cycle being induced at late G1 phase. They also suggest that these channels are involved in the maintenance of the undifferentiated state of mouse ES cells. We propose that Ca(2+) entry mediated by Ca(v)3.2 channels might be one of the intracellular signals that participate in the complex network responsible for ES cell self-renewal.
authors: Instituto de Biomedicina de Sevilla, Campus Hospital Universitario Virgen del Rocío, Seville, Spain.
authors: José A
authors: JA
authors: Rodríguez-Gómez
authors: Konstantín L
authors: KL
authors: Levitsky
authors: José
authors: J
authors: López-Barneo
mesh_terms: D000469:Alkaline Phosphatase / Q000096:biosynthesis; D000818:Animals; D002118:Calcium / Q000378:metabolism; D020747:Calcium Channels, T-Type / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D002453:Cell Cycle / Q000187:drug effects / Q000502:physiology*; D002454:Cell Differentiation; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D053595:Embryonic Stem Cells / Q000378:metabolism*; D018398:Homeodomain Proteins / Q000096:biosynthesis; D047908:Intracellular Signaling Peptides and Proteins / Q000502:physiology; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D051379:Mice; D000071317:Nanog Homeobox Protein; D009532:Nickel / Q000494:pharmacology; D050814:Octamer Transcription Factor-3 / Q000096:biosynthesis; D018408:Patch-Clamp Techniques; D034622:RNA Interference; D012333:RNA, Messenger / Q000096:biosynthesis; D034741:RNA, Small Interfering; D026941:Sodium Channel Blockers / Q000494:pharmacology; D013779:Tetrodotoxin / Q000494:pharmacology; D050994:Voltage-Dependent Anion Channels
chemical_list: C504883:Cacna1h protein, mouse; D020747:Calcium Channels, T-Type; D018398:Homeodomain Proteins; D047908:Intracellular Signaling Peptides and Proteins; D000071317:Nanog Homeobox Protein; C475540:Nanog protein, mouse; D050814:Octamer Transcription Factor-3; C494174:Pou5f1 protein, mouse; D012333:RNA, Messenger; D034741:RNA, Small Interfering; D026941:Sodium Channel Blockers; D050994:Voltage-Dependent Anion Channels; D013779:Tetrodotoxin; D009532:Nickel; D000469:Alkaline Phosphatase; D002118:Calcium