Influence of short-time feeding of rats with an iron-deficient diet on their hepatic gene expression profiles

Iron deficiency-induced anemia is generally a representative nutritional problem in most populations. We reported that the anemia due to dietary iron deficiency causes a variety of changes in nutrient metabolism, even leading to apoptosis as a result of associated endoplasmic reticulum (ER) stress in the rat liver. On the other hand, it appears that non-anemic iron-deficiency causes no serious problem because no appreciable down-regulation of hemoglobin synthesis occurs. Biochemically, iron is essential for activation of cytochrome-related enzymes and its deficiency should yield some physiological problems. We performed a comprehensive transcriptome analysis to define the effects of non-anemic iron deficiency on hepatic gene expression. Four-week-old rats were fed a low-iron diet (ca. 3 ppm iron) for 2 days. These rats were compared with those fed a control diet (48 ppm iron) by pair feeding. On day 3, the rats were sacrificed under anesthesia, and their livers were dissected for DNA microarray analysis. Rats in the iron-deficient diet group, showed that their serum ferritin and iron levels decreased with an increase in the serum total iron binding capacity (TIBC) level, while the hemoglobin level was not changed. In the DNA microarray study, we identified 91 up-regulated and 186 down-regulated probe sets that characterized the iron-deficient diet group. In the up-regulated probe sets, genes involved in glucose and lipid metabolic processes were significantly enriched, whereas genes related to organic acid metabolic process, cellular ketone metabolic process, lipid metabolic process, oxidation reduction, response to drug, response to extracellular stimulus and gas transport were significantly enriched in the down-regulated probe sets. These results suggest that even the non-anemic iron-deficiency exerts various influences on nutrient metabolisms in the liver.

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Kamei A, Watanabe Y, Kondo K, Okada S, Shinozaki F, Ishijima T, Nakai Y, Kondo T, Arai S, Abe K