Characterization of Selenoprotein M and Its Response to Selenium Deficiency in Chicken Brain

Area of Science:

• Biochemistry
• Neuroscience
• Animal Nutrition

Background:

• Selenoprotein M (SelM) is involved in redox regulation and calcium signaling, with potential links to neurodegenerative diseases like Alzheimer's.
• Limited research exists on SelM's role and regulation in avian species, particularly in the context of dietary selenium.
• Dietary selenium is crucial for selenoprotein synthesis and overall antioxidant defense in animals.

Purpose of the Study:

• To investigate the effects of selenium deficiency on the expression of Selenoprotein M (Selm), Selenoprotein T (Selt), and Selenoprotein W (Selw) in the chicken brain.
• To assess the impact of selenium deficiency on oxidative stress markers and selenium status in the brains of broiler chicks.
• To explore the potential role of SelM in protecting the chicken brain against oxidative damage.

Main Methods:

• Broiler chicks were fed either a basal diet or a selenium-supplemented diet.
• Brain tissues were collected at various ages (14, 21, 28, and 42 days).
• Sequence analysis, gene expression (mRNA), protein abundance, selenium content, and enzyme activities (GPx, CAT) were measured.

Main Results:

• Selenium deficiency significantly decreased brain selenium content, glutathione peroxidase (GPx), and catalase (CAT) activities.
• Malondialdehyde (MDA) levels, an indicator of lipid peroxidation, were increased in selenium-deficient brains.
• Selenium deficiency reduced Selm mRNA expression and SelM protein abundance, while Selt and Selw mRNA levels remained unaffected.

Conclusions:

• Dietary selenium deficiency negatively impacts antioxidant status and SelM expression in the chicken brain.
• SelM appears to play a significant role in protecting the chicken brain from oxidative damage.
• The differential regulation of Selm, Selt, and Selw by selenium deficiency is a novel finding with implications for understanding neuroprotection.