title: Equilibrative nucleoside transporter 1 plays an essential role in cardioprotection.
abstract: To better understand the role of equilibrative nucleoside transporters (ENT) in purine nucleoside-dependent physiology of the cardiovascular system, we investigated whether the ENT1-null mouse heart was cardioprotected in response to ischemia (coronary occlusion for 30 min followed by reperfusion for 2 h). We observed that ENT1-null mouse hearts showed significantly less myocardial infarction compared with wild-type littermates. We confirmed that isolated wild-type adult mouse cardiomyocytes express predominantly ENT1, which is primarily responsible for purine nucleoside uptake in these cells. However, ENT1-null cardiomyocytes exhibit severely impaired nucleoside transport and lack ENT1 transcript and protein expression. Adenosine receptor expression profiles and expression levels of ENT2, ENT3, and ENT4 were similar in cardiomyocytes isolated from ENT1-null adult mice compared with cardiomyocytes isolated from wild-type littermates. Moreover, small interfering RNA knockdown of ENT1 in the cardiomyocyte cell line, HL-1, mimics findings in ENT1-null cardiomyocytes. Taken together, our data demonstrate that ENT1 plays an essential role in cardioprotection, most likely due to its effects in modulating purine nucleoside-dependent signaling and that the ENT1-null mouse is a powerful model system for the study of the role of ENTs in the physiology of the cardiomyocyte.
authors.affiliation: Dept. of Biology, York Univ., Toronto, ON, Canada.
authors.forename: Jennifer B
authors.initials: JB
authors.lastname: Rose
authors.forename: Zlatina
authors.initials: Z
authors.lastname: Naydenova
authors.forename: Andrew
authors.initials: A
authors.lastname: Bang
authors.forename: Megumi
authors.initials: M
authors.lastname: Eguchi
authors.forename: Gary
authors.initials: G
authors.lastname: Sweeney
authors.forename: Doo-Sup
authors.initials: DS
authors.lastname: Choi
authors.forename: James R
authors.initials: JR
authors.lastname: Hammond
authors.forename: Imogen R
authors.initials: IR
authors.lastname: Coe
mesh_terms: D000818:Animals; D002460:Cell Line; D002478:Cells, Cultured; D004195:Disease Models, Animal; D033721:Equilibrative Nucleoside Transporter 1 / Q000235:genetics / Q000502:physiology*; D005260:Female; D051379:Mice; D008822:Mice, Transgenic; D023421:Models, Animal; D015428:Myocardial Reperfusion Injury / Q000503:physiopathology* / Q000517:prevention & control*; D032383:Myocytes, Cardiac / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D011684:Purine Nucleosides / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D018047:Receptors, Purinergic P1 / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology
chemical_list: D033721:Equilibrative Nucleoside Transporter 1; D011684:Purine Nucleosides; D034741:RNA, Small Interfering; D018047:Receptors, Purinergic P1