Transgenic cardiac-targeted overexpression of human thymidylate kinase.
Thymidylate kinase (TMPK) is a nucleoside monophosphate kinase that catalyzes phosphorylation of thymidine monophosphate to thymidine diphosphate. TMPK also mediates phosphorylation of monophosphates of thymidine nucleoside analog (NA) prodrugs on the pathway to their active triphosphate antiviral or antitumor moieties. Novel transgenic mice (TG) expressing human (h) TMPK were genetically engineered using the alpha-myosin heavy chain promoter to drive its cardiac-targeted overexpression. In '2 by 2' protocols, TMPK TGs and wild-type (WT) littermates were treated with the NA zidovudine (a deoxythymidine analog, 3'-azido-3'deoxythymidine (AZT)) or vehicle for 35 days. Alternatively, TGs and WTs were treated with a deoxycytidine NA (racivir, RCV) or vehicle. Changes in mitochondrial DNA (mtDNA) abundance and mitochondrial ultrastructure were defined quantitatively by real-time PCR and transmission electron microscopy, respectively. Cardiac performance was determined echocardiographically. Results showed TMPK TGs treated with either AZT or RCV exhibited decreased cardiac mtDNA abundance. Cardiac ultrastructural changes were seen only with AZT. AZT-treated TGs exhibited increased left ventricle (LV) mass. In contrast, LV mass in RCV-treated TGs and WTs remained unchanged. In all cohorts, LV end-diastolic dimension remained unchanged. This novel cardiac-targeted overexpression of hTMPK helps define the role of TMPK in mitochondrial toxicity of antiretrovirals.
Kohler
James J
JJ
Department of Pathology, Emory University School of Medicine, Atlanta, GA, USA. jjkohle@emory.edu
Hosseini
Seyed H
SH
Cucoranu
Ioan
I
Zhelyabovska
Olga
O
Green
Elgin
E
Ivey
Kristopher
K
Abuin
Allison
A
Fields
Earl
E
Hoying
Amy
A
Russ
Rodney
R
Santoianni
Robert
R
Raper
C Michael
CM
Yang
Qinglin
Q
Lavie
Arnon
A
Lewis
William
W
D000818:Animals; D019380:Anti-HIV Agents / Q000378:metabolism / Q000633:toxicity*; D004261:DNA Replication / Q000187:drug effects; D004272:DNA, Mitochondrial / Q000187:drug effects / Q000378:metabolism*; D004452:Echocardiography; D000068679:Emtricitabine / Q000031:analogs & derivatives; D005260:Female; D006801:Humans; D017379:Hypertrophy, Left Ventricular / Q000139:chemically induced / Q000000981:diagnostic imaging; D008297:Male; D051379:Mice; D008822:Mice, Transgenic; D008929:Mitochondria, Heart / Q000187:drug effects / Q000648:ultrastructure; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology / Q000648:ultrastructure; D009703:Nucleoside-Phosphate Kinase / Q000235:genetics / Q000378:metabolism*; D009705:Nucleosides / Q000378:metabolism*; D010766:Phosphorylation; D016277:Ventricular Function, Left; D016047:Zalcitabine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000633:toxicity; D015215:Zidovudine / Q000378:metabolism / Q000633:toxicity*
D019380:Anti-HIV Agents; D004272:DNA, Mitochondrial; D009705:Nucleosides; D015215:Zidovudine; D016047:Zalcitabine; D009703:Nucleoside-Phosphate Kinase; C020093:dTMP kinase; D000068679:Emtricitabine; C075889:Racivir