MCT-4, A511/Basigin and EF5 expression patterns during early chick cardiomyogenesis indicate cardiac cell differentiation occurs in a hypoxic environment.
We have identified the presence of the hypoxia marker EF5 in the stage 4/5 chick heart fields. This suggests that cardiac cell differentiation occurs in a relatively anaerobic environment. Monocarboxylate transporter (MCT) studies in adult cardiac myocytes have demonstrated that MCTs catalyze proton-linked pyruvate and lactate transport activity. 5A11/Basigin is an ancillary protein that targets MCTs to the plasma membrane for their function. MCT-4 expression is most evident in cells with a high glycolytic rate associated with hypoxic energy production. Subsequent to the immunohistochemical localization of EF5 in the early heart field, we continued in our analysis during stages 5 to 12 for the expression of indicators of cellular glycolytic metabolism in the developing heart, such as MCT-4, MCT-1, and 5A11 (Basigin/CD147). Our observations indicate that MCT-4 and 5A11/Basigin are expressed early, in a differential left-right pattern, in the bi-lateral plate mesoderm, as the cardiac compartment is forming. At stage 11, MCT-4/5A11 continues to be highly expressed in the myocardial wall of the looping heart, but not in the dorsal mesocardium. RT-PCR analyses for MCT-1, -4, and 5A11 indicate that MCT-4 and 5A11 are expressed throughout precardiac, embryonic, and fetal stages in the heart. MCT-1 is first detected in the heart on embryonic day 3 and then remains expressed throughout development to hatching. These results indicate that cardiac precursor cells are equipped for differentiating in a hypoxic environment using anaerobic metabolism for energy production.
Han
Mingda
M
Department of Pediatrics, USF-Children's Research Institute, St. Petersburg, Florida 33701, USA.
Trotta
Patrizia
P
Coleman
Carl
C
Linask
Kersti K
KK
D000818:Animals; D030161:Avian Proteins / Q000096:biosynthesis* / Q000235:genetics; D051926:Basigin / Q000096:biosynthesis* / Q000235:genetics; D015415:Biomarkers; D002454:Cell Differentiation / Q000502:physiology*; D002642:Chick Embryo; D017341:Etanidazole / Q000031:analogs & derivatives* / Q000378:metabolism; D006845:Hydrocarbons, Fluorinated / Q000378:metabolism*; D000860:Hypoxia / Q000378:metabolism*; D027501:Monocarboxylic Acid Transporters / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000166:cytology* / Q000378:metabolism; D005466:Fluorocarbons
D030161:Avian Proteins; D051926:Basigin; D015415:Biomarkers; D017341:Etanidazole; D006845:Hydrocarbons, Fluorinated; D027501:Monocarboxylic Acid Transporters; C096011:2-(2-nitro-1H-imidazol-1-yl)-N-(2,2,3,3,3-pentafluoropropyl)acetamide; D005466:Fluorocarbons