Iron-induced epigenetic abnormalities of mouse bone marrow through aberrant activation of aconitase and isocitrate dehydrogenase.

Iron overload remains a concern in myelodysplastic syndrome (MDS) patients. Iron chelation therapy (ICT) thus plays an integral role in the management of these patients. Moreover, ICT has been shown to prolong leukemia-free survival in MDS patients; however, the mechanisms responsible for this effect are unclear. Iron is a key molecule for regulating cytosolic aconitase 1 (ACO1). Additionally, the mutation of isocitrate dehydrogenase (IDH), the enzyme downstream of ACO1 in the TCA cycle, is associated with epigenetic abnormalities secondary to 2-hydroxyglutarate (2-HG) and DNA methylation. However, epigenetic abnormalities observed in many MDS patients occur without IDH mutation. We hypothesized that iron itself activates the ACO1-IDH pathway, which may increase 2-HG and DNA methylation, and eventually contribute to leukemogenesis without IDH mutation. Using whole RNA sequencing of bone marrow cells in iron-overloaded mice, we observed that the enzymes, phosphoglucomutase 1, glycogen debranching enzyme, and isocitrate dehydrogenase 1 (Idh1), which are involved in glycogen and glucose metabolism, were increased. Digital PCR further showed that Idh1 and Aco1, enzymes involved in the TCA cycle, were also elevated. Additionally, enzymatic activities of TCA cycle and methylated DNA were increased. Iron chelation reversed these phenomena. In conclusion, iron activation of glucose metabolism causes an increase of 2-HG and DNA methylation.

[Evaluation of Basic Performance of "Point Strip ferritin-3000" for Simple and Rapid Quantification of Serum Ferritin].

Serum ferritin is an excellent marker for total iron content in the body and is essential for the diagnosis of iron deficiency or iron overload. Recently, a simple and rapid method, which utilizes immunochromatography for the quantification of serum ferritin, was developed. However, the range of measurement in previous reagents was limited (10-500 ng/mL). This range is rather narrow and is not fully helpful for the diagnosis of iron overload which sometimes occurs as a result of prolonged transfusions, or for monitoring iron contents during iron chelation therapy against iron overload. In the present study we evaluated the basic performance of the newly developed "Point Strip ferritin-3000", which can measure serum ferritin in the range of 300-3,000 ng/mL. Coefficient of variation (CV) s of within and inter-day assays were in the ranges of 7.3-11.1% and 2.1-5.2%, respectively. Using 87 serum samples obtained from the patients with written informed consents, the correlation coefficient was calculated to be 0.93 compared to the control method. In addition, the quantification of serum ferritin by "Point Strip ferritin-3000" was not influenced by bilirubin, hemoglobin, chyle, rheumatoid factor, or ascorbic acid. From our data, "Point Strip ferritin-3000" is reliable reagent in the range of 300-3,000 ng/mL, and is therefore considered to be useful for the diagnosis of iron overload, as well as for monitoring iron contents during iron chelation therapy. In addition, this quantification method can be easily performed using a small desktop equipment without any special technique, making this system applicable for epidemiological surveys and clinical studies.