title: A systemic approach to explore the flexibility of energy stores at the cellular scale: Examples from muscle cells.
abstract: Variations in energy storage and expenditure are key elements for animals adaptation to rapidly changing environments. Because of the multiplicity of metabolic pathways, metabolic crossroads and interactions between anabolic and catabolic processes within and between different cells, the flexibility of energy stores in animal cells is difficult to describe by simple verbal, textual or graphic terms. We propose a mathematical model to study the influence of internal and external challenges on the dynamic behavior of energy stores and its consequence on cell energy status. The role of the flexibility of energy stores on the energy equilibrium at the cellular level is illustrated through three case studies: variation in eating frequency (i.e., glucose input), level of physical activity (i.e., ATP requirement), and changes in cell characteristics (i.e., maximum capacity of glycogen storage). Sensitivity analysis has been performed to highlight the most relevant parameters of the model; model simulations have then been performed to illustrate how variation in these key parameters affects cellular energy balance. According to this analysis, glycogen maximum accumulation capacity and homeostatic energy demand are among the most important parameters regulating muscle cell metabolism to ensure its energy equilibrium.
authors.affiliation: PEGASE, AgroCampus Ouest, INRA, 35590 Saint-Gilles, France. Electronic address: Masoomeh.Taghipoor@rennes.inra.fr.
authors.forename: Masoomeh
authors.initials: M
authors.lastname: Taghipoor
authors.affiliation: PEGASE, AgroCampus Ouest, INRA, 35590 Saint-Gilles, France.
authors.forename: Jaap
authors.initials: J
authors.lastname: van Milgen
authors.affiliation: PEGASE, AgroCampus Ouest, INRA, 35590 Saint-Gilles, France.
authors.forename: Florence
authors.initials: F
authors.lastname: Gondret
mesh_terms: D000244:Adenosine Diphosphate / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000378:metabolism; D004734:Energy Metabolism; D005947:Glucose / Q000378:metabolism; D006003:Glycogen / Q000378:metabolism; D053858:Metabolic Networks and Pathways; D055442:Metabolome; D008954:Models, Biological; D032342:Muscle Cells / Q000378:metabolism*; D010641:Phenotype; D013997:Time Factors
chemical_list: D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate; D006003:Glycogen; D005947:Glucose
keywords: Dynamic model; Eating frequency; Glycogen; Lipids; Metabolism flexibility