GC–MS metabolic profiling reveals fructose-2,6-bisphosphate regulates branched chain amino acid metabolism in the heart during fasting
As an insulin sensitive tissue, the heart decreases glucose usage during fasting. This response is mediated, in part, by decreasing phosphofructokinase-2 (PFK-2) activity and levels of its product fructose-2,6-bisphosphate. However, the importance of fructose-2,6-bisphosphate in the fasting response on other metabolic pathways has not been evaluated.
The goal of this study is to determine how sustaining cardiac fructose-2,6-bisphosphate levels during fasting affects the metabolomic profile.
Control and transgenic mice expressing a constitutively active form of PFK-2 (GlycoHi) were subjected to either 12-h fasting or regular feeding. Animals (n = 4 per group) were used for whole-heart extraction, followed by gas chromatography–mass spectrometry metabolic profiling and multivariate data analysis.
Principal component analysis displayed differences between Control and GlycoHi groups under both fasting and fed conditions while a clear response to fasting was observed only for Control animals. However, pathway analysis revealed that these smaller changes in the GlycoHi group were significantly associated with branched-chain amino acid (BCAA) metabolism (~ 40% increase in all BCAAs). Correlation network analysis demonstrated clear differences in response to fasting between Control and GlycoHi groups amongst most parameters. Notably, fasting caused an increase in network density in the Control group from 0.12 to 0.14 while the GlycoHi group responded oppositely (0.17–0.15).
Elevated cardiac PFK-2 activity during fasting selectively increases BCAAs levels and decreases global changes in metabolism.
KeywordsGC–MS metabolomics Heart pathologies Cardiac metabolism Correlation network
AB, SM, MN, TG and KH conceived and designed research. AB, SM, MN, MW and KH conducted experiments. AB, SM, TG and KH analyzed data. AB, TG and KH wrote the manuscript. All authors red and approved the manuscript.
This work was supported by National Institutes of Health (NIH) grant R01HL125625, from the National Heart, Lung, and Blood Institute, with additional equipment support from the Oklahoma Center for Adult Stem Cell Research, a program of TSET.
Compliance with ethical Standards
Conflict of interest
The authors declare that they have no conflict of interest.
All applicable international, national, and/or institutional guidelines for the care and use of animals were followed.
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