Cellular Iron Deficiency Disrupts Thyroid Hormone Regulated Gene Expression in Developing Hippocampal Neurons

Area of Science:

• Neuroscience
• Developmental Biology
• Nutritional Neuroscience

Background:

• Developing neurons require adequate iron and thyroid hormone for optimal metabolism and growth.
• Early-life deficiencies in iron and thyroid hormone are common and linked to neurodevelopmental impairments.
• Iron deficiency in early life can disrupt thyroid hormone levels and gene expression in the brain.

Approach:

• Investigated the impact of neuronal iron deficiency on thyroid hormone-regulated gene expression in primary mouse embryonic hippocampal neuron cultures.
• Induced iron deficiency using deferoxamine (DFO) and assessed mRNA levels of genes involved in thyroid hormone homeostasis and neurodevelopment.
• Examined the effects of iron repletion on gene expression and cellular ATP levels.

Key Points:

• Neuronal iron deficiency altered the expression of genes critical for thyroid hormone homeostasis and neurodevelopment.
• Thyroid hormone homeostatic genes correlated with and predicted iron status.
• Iron repletion partially restored neurodevelopmental gene expression but did not fully normalize thyroid hormone homeostatic genes or ATP levels.
• Gene expression patterns after iron repletion suggested a lasting signature of prior iron deficiency.

Conclusions:

• An intracellular mechanism likely coordinates iron and thyroid hormone activities to regulate neuronal energy production and growth signaling.
• Persistent deficits in thyroid hormone-dependent neurodevelopmental processes may occur even after recovery from early-life iron deficiency.