Selenoproteins and their Role in Oxidative Stress and Inflammation

The discovery of selenocysteine as the 21st amino acid has revolutionized the understanding of the significance of the essential micronutrient selenium in human and animal health. About 25 different selenoproteins have been identified that collectively function to detoxify reactive oxygen and nitrogen species (RONS) and thus aid in maintaining an optimal redox tone as a vital component of the antioxidant defense system of cells. Knowledge about the physiological properties of the redox-sensitive transcription factors like nuclear factor-kappa B (NF-κB) has made it clear that oxidative stress is an important factor that triggers and sustains inflammation in various disease states. Moreover, there is emerging epidemiological data suggesting a positive association between selenium deficiency and the prevalence of diseases such as atherosclerosis, rheumatoid arthritis, viral infections including HIV-AIDS, and cancer, where chronic inflammation forms the underlying basis of the disease. Recent studies in our laboratory have shown that selenoproteins modulate many cellular regulatory pathways that influence the expression of pro- and anti-inflammatory genes. Thus, elucidation of the diverse molecular mechanisms involved in the anti-inflammatory properties of selenium is important to appreciate its role in disease prevention and treatment. This article reviews the current status of knowledge on the biology of selenium with an emphasis on inflammation.