Changes of HCN gene expression and I(f) currents in Nkx2.5-positive cardiomyocytes derived from murine embryonic stem cells during differentiation.
Changes in the expression of hyperpolarization-activated cyclic nucleotide (HCN)-gated channels and I(f) currents during the differentiation of embryonic stem cells into cardiac cells remain unknown. We examined changes of HCN genes in expression and function during the differentiation of Nkx2.5-positive cardiac precursor cells derived from mouse ES cells using cell sorting, RTPCR, immunofluorescence and whole cell patch-clamp techniques. Cs(+)-induced inhibition of automaticity and transcription of HCN genes increased during differentiation. Expressions of Nkx2.5, a marker of cardiac progenitor cell, and Flk1, a marker of hemangioblast, were mutually exclusive. Messenger RNA and proteins encoded by HCN1 and 4 genes were predominantly observed in Nkx2.5-positive cells on day 15, although Flk1-positive cells did not express genes of the HCN family on that day. Cs(+)-induced prolongation of the cycle of spontaneous action potentials and I(f) currents were predominantly observed on day 15. These results suggested that a fraction of Nkx2.5-positive cardiac precursor cells was committed to pacemaking cells expressing I(f) channels predominantly encoded by HCN 1 and 4 genes.
Yano
Shuichi
S
Department of Cardiovascular Medicine, Tottori University Faculty of Medicine, Japan.
Miake
Junichiro
J
Mizuta
Einosuke
E
Manabe
Kasumi
K
Bahrudin
Udin
U
Morikawa
Kumi
K
Arakawa
Keita
K
Sasaki
Norihito
N
Igawa
Osamu
O
Shigemasa
Chiaki
C
Yamamoto
Yasutaka
Y
Morisaki
Takayuki
T
Hidaka
Kyoko
K
Kurata
Yasutaka
Y
Yoshida
Akio
A
Shiota
Goshi
G
Higaki
Katsumi
K
Ninomiya
Haruaki
H
Lee
Jong-Kook
JK
Shirayoshi
Yasuaki
Y
Hisatome
Ichiro
I
D000818:Animals; D002454:Cell Differentiation / Q000502:physiology*; D002460:Cell Line; D002469:Cell Separation; D002586:Cesium / Q000378:metabolism; D054815:Cyclic Nucleotide-Gated Cation Channels / Q000235:genetics / Q000378:metabolism; D053595:Embryonic Stem Cells / Q000166:cytology / Q000502:physiology*; D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D064428:Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels; D051379:Mice; D032383:Myocytes, Cardiac / Q000166:cytology / Q000502:physiology*; D018408:Patch-Clamp Techniques; D015221:Potassium Channels / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000235:genetics / Q000378:metabolism
D054815:Cyclic Nucleotide-Gated Cation Channels; C578665:HCN1 protein, human; C578666:Hcn1 protein, mouse; D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins; D064428:Hyperpolarization-Activated Cyclic Nucleotide-Gated Channels; C484469:Nkx2-5 protein, mouse; D015221:Potassium Channels; D012333:RNA, Messenger; D014157:Transcription Factors; D002586:Cesium; D040301:Vascular Endothelial Growth Factor Receptor-2