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de Baat, A.

Publications and source records attributed to de Baat, A..

2 recordsLinked to original sources

Homeostatic feedback model of energy metabolism with adaptive enzyme levels exhibits problem solving behavior

Metabolic networks are typically viewed as homeostatic systems that stabilize flux, energy charge, redox balance, and metabolite availability under perturbation. However, it remains unclear whether the same feedback architectures that support metabolic robustness can also generate learning-like, experience-dependent adaptation. Here, we develop a coarse-grained dynamical model of mammalian energy metabolism to test whether prior perturbation can improve future metabolic responses. The model represents core glucose, glutamine, fatty acid, and oxidative phosphorylation pathways as coupled ordinary differential equations with Michaelis-Menten-type fluxes, product-inhibition feedback, adaptive enzyme-capacity regulation, and explicit ATP costs for enzyme adjustment. Rather than aiming to reproduce quantitative fluxes for a specific cell type, the framework is designed to expose how metabolic feedback, regulatory cost, repeated perturbation, and environmental variability interact. We use this model to ask whether adaptive enzyme regulation enables improved recovery after repeated challenges, whether such effects depend on energetic control costs, and whether environmental variability broadens or constrains the set of reachable adaptive states. This approach provides a tractable way to investigate how homeostatic metabolic regulation may give rise to experience-dependent metabolic plasticity.

systems biology↗

Cystine/glutamate antiporter system Xc- deficiency impairs insulin secretion.

System Xc-, encoded by Slc7a11, is an antiporter that exports glutamate and imports cystine. Cystine is used for protein synthesis and incorporation in thiol peptides such as glutathione, which function as cofactors for reactive oxygen species scavenging enzymes. Glutamate export by astrocytes through system Xc- has been implicated in excitotoxicity, a form of neurotoxicity that has been postulated to also occur in insulin-producing beta-cells in the pancreatic islets. This study describes the implications of Slc7a11 deficiency on glucose metabolism in both constitutive and myeloid cells-specific knockout mice. Constitutive Slc7a11 deficiency leads to drastically lowered glutathione levels in the pancreatic islets and immune cells in addition to diminished insulin secretion both in vitro and in vivo. Macrophage-specific deletion did not have a significant impact on metabolism or islet function. These findings suggest that system Xc- is required for glutathione maintenance and insulin production in beta-cells, but is dispensable for islet macrophage function.

molecular biology↗