The bioactivity of Poplar root extracts as a novel treatment for iron overload in a THP-1 cell culture model
Date
2022
Authors
Anderson, Julie
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Abstract
Iron is an essential element for all living beings. However, either too little or too much iron can be detrimental. Non-protein bound iron is highly reactive due to its ability to easily accept and donate electrons. This makes iron a powerful and essential component in many metabolic and physiological processes, but it also poses a potential oxidative danger. Consequently, iron uptake, storage, and recycling are tightly regulated under normal circumstances. In cases of systemic iron overload, excess iron in the body causes extensive damage to DNA, proteins, and other macromolecules, eventually leading to tissue and organ damage. The current leading treatment for diseases of iron overload in humans is chelation therapy, in which iron chelators, molecules that bind and sequester iron, are administered. However, chelator treatments can have cytotoxic effects, driving the search for novel chelator treatment options. In my research, the potential bioactivity of iron chelators present in poplar root extracts were investigated in a simple iron-overload model using a human leukemia monocytic THP-1 cell line. Root extracts were harvested from poplars grown under iron reduced conditions, which we hypothesise to stimulate biosynthesis of chelators, and iron normal conditions as controls. The impact of these growth conditions on root chelator production was examined. To assess the potential of poplar root extracts as a novel bioactive chelators for iron-overload treatment in humans, we measured the intracellular iron content of THP-1 cells under iron overload conditions and after treatment with the clinically used iron chelator deferoxamine in comparison to root extracts. Intracellular iron normalized to protein concentrations as a proxy for cell number. Intracellular iron concentration, measured using ferrozine, was increased in response to chronic iron treatment relative to control cells grown under iron normal conditions. Relative to cells treated with chronic iron overload, it was found that DFO reduced intracellular iron content of chronically iron overloaded cells by 33% (p = 0.020). Iron normal and iron reduced poplar root extracts also reduced iron content by 17% and 15% on average, but these trends were not significant. There was no significant difference between the iron content of cells treated with either poplar root extract and DFO. Unexpectedly, there was no difference in the iron content of cells treated with extracts from roots of plants grown under iron normal and iron reduced poplar conditions (p = 0.878). Trypan blue staining illustrated that chelator treatments had little effect on cell viability, indicating low cytotoxicity of root extracts. Future investigations of the potential bioactivity of iron chelators present in poplar root extracts should examine the chelating abilities of poplar root extracts with increasing concentration. Furthermore, metabolic characterization of the root extracts would help identify individual compounds of interest, and to improve the effectiveness of the screening process.