Functional characterization of cardiac progenitor cells and their derivatives in the embryonic heart post-chamber formation.
There is scant information on the fate of cardiac progenitor cells (CPC) in the embryonic heart after chamber specification. Here we simultaneously tracked three lineage-specific markers (Nkx2.5, MLC2v, and ANF) and confirmed that CPCs with an Nkx2.5+MLC2v-ANF- phenotype are present in the embryonic (E) day 11.5 mouse ventricular myocardium. We demonstrated that these CPCs could give rise to working cardiomyocytes and conduction system cells. Using a two-photon imaging analysis, we found that the majority of CPCs are not capable of developing Ca2+ transients in response to beta-adrenergic receptor stimulation. In contrast, Nkx2.5+ cells expressing MLC2v but not ANF are capable of developing functional Ca2+ transients. We showed that Ca2+ transients could be invoked in Nkx2.5+MLC2v+ANF+ cells only upon inhibition of Gi, muscarinic receptors, or nitric oxide synthase (NOS) signaling pathways. Our data suggest that these inhibitory pathways may delay functional specification in a subset of developing ventricular cells.
Department of Pharmacology, Dalhousie University, Halifax, Nova Scotia, Canada.
Nichole M
NM
McMullen
Feixiong
F
Zhang
Adam
A
Hotchkiss
Frederic
F
Bretzner
Jennifer M
JM
Wilson
Hong
H
Ma
Karim
K
Wafa
Robert M
RM
Brownstone
Kishore B S
KB
Pasumarthi
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism*; D004622:Embryo, Mammalian / Q000196:embryology* / Q000378:metabolism; D006352:Heart Ventricles / Q000196:embryology* / Q000378:metabolism / Q000648:ultrastructure; D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins / Q000378:metabolism; D051379:Mice; D046529:Microscopy, Electron, Transmission; D032386:Myoblasts, Cardiac / Q000378:metabolism* / Q000648:ultrastructure; D009206:Myocardium / Q000378:metabolism / Q000648:ultrastructure; D032383:Myocytes, Cardiac / Q000378:metabolism* / Q000648:ultrastructure; D018994:Myosin Light Chains / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism; D011943:Receptors, Adrenergic, beta / Q000378:metabolism; D011976:Receptors, Muscarinic / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D014157:Transcription Factors / Q000378:metabolism
D015220:Calcium Channels; D000072576:Homeobox Protein Nkx-2.5; D018398:Homeodomain Proteins; C521958:Mylpf protein, mouse; D018994:Myosin Light Chains; C484469:Nkx2-5 protein, mouse; D011943:Receptors, Adrenergic, beta; D011976:Receptors, Muscarinic; D014157:Transcription Factors; D009320:Atrial Natriuretic Factor; D019001:Nitric Oxide Synthase; D002118:Calcium