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Biology subjects

Harder, N. H. O.

Publications and source records attributed to Harder, N. H. O..

2 recordsLinked to original sources

High Glucose Diet Induces Hepatic Iron Overload Contributing to Metabolic Dysfunction

Iron is an essential biometal, critical in processes that include oxygen transport, mitochondrial respiration, and cell signaling. Iron dyshomeostasis is linked with hyperglycemia and associated metabolic disorders, but the underlying mechanisms are poorly understood. To investigate these mechanisms, we conducted a short-term, four-week, in vivo study on mice given water supplemented with glucose. The short time frame was sufficient to cause metabolic shifts in the liver towards triglyceride synthesis. We sought to comprehensively track iron trafficking by analyzing liver and serum markers of iron metabolism alongside LC-ICP-MS analysis of iron speciation, which is a new approach in this context. Glucose supplementation induced changes in iron regulation despite equal dietary iron intake between groups. Specifically, we observed increased uptake of transferrin-bound iron from the serum and an iron overload state in the liver. We developed and applied a cell-based models of this glucose-induced iron overload state and found that, on the one hand, the anti-diabetic drug metformin could restore iron regulation; on the other hand, the iron chelator, deferoxamine, could restore glucose metabolism. Taken together, our studies reveal that early hyperglycemia is sufficient to cause disruptions in iron regulations, pointing to iron overload as viable therapeutic target in metabolic dysfunction.

biochemistry↗

The role of intestine in metabolic dysregulation in murine Wilson disease

Background and aimsMajor clinical manifestations of Wilson disease (WD) are related to copper accumulation in the liver and the brain, and little is known about other tissues involvement in metabolic changes in WD. In vitro studies suggested that the loss of intestinal ATP7B could contribute to metabolic dysregulation in WD. We tested this hypothesis by evaluating gut microbiota and lipidome in two mouse models of WD and by characterizing a new mouse model with a targeted deletion of Atp7b in intestine. MethodsCecal content 16S sequencing and untargeted hepatic and plasma lipidome analyses in the Jackson Laboratory toxic-milk and the Atp7b null global knockout mouse models of WD were profiled and integrated. Intestine-specific Atp7b knockout mice (Atp7b{Delta}IEC) was generated using B6.Cg-Tg(Vil1-cre)997Gum/J mice and Atp7bLox/Lox mice, and characterized using targeted lipidome analysis following a high-fat diet challenge. ResultsGut microbiota diversity was reduced in animal models of WD. Comparative prediction analysis revealed amino acid, carbohydrate, and lipid metabolism functions to be dysregulated in the WD gut microbial metagenome. Liver and plasma lipidomic profiles showed dysregulated tri- and diglyceride, phospholipid, and sphingolipid metabolism in WD models. When challenged with a high-fat diet, Atp7b{Delta}IEC mice exhibited profound alterations to fatty acid desaturation and sphingolipid metabolism pathways as well as altered APOB48 distribution in intestinal epithelial cells. ConclusionCoordinated changes of gut microbiome and lipidome analyses underlie systemic metabolic manifestations in murine WD. Intestine-specific ATP7B deficiency affected both intestinal and systemic response to a high-fat challenge. WD is a systemic disease in which intestinal-specific ATP7B loss and diet influence phenotypic presentations.

molecular biology↗