The Possible Mechanism of Physiological Adaptation to the Low-Se Diet and Its Health Risk in the Traditional Endemic Areas of Keshan Diseases

Abstract

Selenium is an essential trace element for humans and animals. As with oxygen and sulfur, etc., it belongs to the sixth main group of the periodic table of elements. Therefore, the corresponding amino acids, such as selenocysteine (Sec), serine (Ser), and cysteine (Cys), have similar spatial structure, physical, and chemical properties. In this review, we focus on the neglected but key role of serine in a possible mechanism of the physiological adaptation to Se-deficiency in human beings with an adequate intake of dietary protein: the insertion of Cys in place of Sec during the translation of selenoproteins dependent on the Sec insertion sequence element in the 3′UTR of mRNA at the UGA codon through a novel serine-dependent pathway for the de novo synthesis of the Cys-tRNA [Ser]Sec , similar to Sec-tRNA [Ser]Sec . We also discuss the important roles of serine in the metabolism of selenium directly or indirectly via GSH, and the maintenance of selenium homostasis regulated through the methylation modification of Sec-tRNA [Ser]Sec at the position 34U by SAM. Finally, we propose a hypothesis to explain why Keshan disease has gradually disappeared in China and predict the potential health risk of the human body in the physiological adaptation state of low selenium based on the results of animal experiments.

Oyster Peptide-Zinc Complex Ameliorates Di-(2-ethylhexyl) Phthalate-Induced Testis Injury in Male Mice and Improving Gut Microbiota

“…Researchers found that zinc supplementation decreased low-dose Pb-induced lipid peroxidation and increased glutathione, CuZn-SOD levels [ 46 , 47 ]. Studies have shown that the dietary selenium deficiency can reduce sperm motility in rats and lead to sperm abnormalities [ 48 ]. Copper exposure resulted in increased MDA concentrations in the testis, mediating oxidative stress that promoted apoptosis and autophagy in testicular cells [ 49 ].…”