Changes in Brain Gene Expression in Nutrient Deficiencies: An Example with Iron

Abstract

Iron is an important element in biological systems, and cellular iron uptake, distribution, and export must be tightly regulated, as both iron deficiency and overload can have deleterious effects on protein, nucleic acid, and lipid contents of the cell. The brain is the organ most vulnerable to iron deficiency during critical periods of development, particularly during the last trimester of fetal life and during the period of brain growth spurt and differentiation. Rodent models have shown that iron deficiency in early life and during adolescence affects both gene expression and the protein levels of a variety of proteins. Genes that are altered by brain iron deficiency are integral to processes including signal transduction, myelin formation, cell growth, energy metabolism, and neurotransmitter signaling. Further, oxidative stress gene profiles of the iron-deficient brain appear similar to those observed in Alzheimer’s disease where iron overaccumulates in neuritic plaques. From the existing literature, it is apparent that while the expression level of many genes can be corrected with iron supplementation, other genes may not be responsive to iron treatment. The presence of genes that are not responsive to treatment suggests that many aspects of brain functioning are likely altered throughout the lifetime leading to undesirable behavioral outcomes.