Thyroid hormone, gene expression, and Central Nervous System: Where we are

Area of Science:

• Endocrinology
• Neuroscience
• Environmental Health

Background:

• Thyroid hormones (TH), including T3 and T4, are essential for gene expression from fetal development through adulthood.
• TH play a critical role in the proper functioning of the central nervous system (CNS).
• Imbalances in TH availability during pregnancy and childhood can result in neurological disorders such as autism, cognitive impairment, and depression.

Purpose of the Study:

• To review the mechanisms by which TH control gene expression.
• To elucidate the role of TH in the CNS.
• To examine the impact of environmental substances on the CNS and thyroid function.

Main Methods:

• Literature review focusing on the molecular mechanisms of TH action.
• Analysis of the interaction between TH, CNS development, and environmental factors.
• Examination of the role of endocrine disruptors in neurodevelopmental mRNA processing.

Main Results:

• TH, primarily T3, exerts its effects through nuclear receptors, influencing numerous CNS genes.
• TH deficiency, caused by iodine lack, impaired hormone synthesis, or genetic defects in transporters/receptors, can lead to neurological impairments.
• Environmental substances can interfere with thyroid gland function, TH activity, and CNS processes.

Conclusions:

• TH are vital for CNS gene expression, affecting oxygen transport, growth factors, myelination, and cell maturation.
• Neurological conditions range from mood dysregulation to severe syndromes like Allan-Herndon-Dudley syndrome.
• Environmental endocrine disruptors pose a significant risk to neurodevelopment by interfering with TH pathways.