Vitamin A Deficiency Decreases the Expression of RARβ and RXRβ/γ in Adult Mouse Brain: Effect of RA Administration

Area of Science:

• Neuroscience
• Molecular Biology
• Nutritional Science

Background:

• Emerging evidence suggests vitamin A influences higher cognitive functions.
• Nuclear receptors, including retinoic acid receptors (RAR and RXR), mediate vitamin A's actions.
• Tissue transglutaminase (tTG) is a gene responsive to these receptors.

Purpose of the Study:

• To investigate the effect of vitamin A deficiency on RAR, RXR, and tTG expression in the adult mouse brain.
• To establish a mouse model for studying vitamin A's neurobiological roles.

Main Methods:

• Induction of vitamin A deficiency in weanling male C57B1/6 mice over 26 weeks.
• Quantification of serum and liver retinol, liver tTG activity, and brain RAR/RXR mRNA levels.
• Administration of retinoic acid (RA) to deficient mice to assess repletion effects.

Main Results:

• Vitamin A deficiency led to decreased serum retinol, liver retinol, liver tTG activity, and brain RAR β and RXR β/γ mRNA.
• Reduced expression of tTG was observed in vitamin A-deficient mice.
• Retinoic acid administration significantly increased the expression of RA nuclear receptors and tTG.

Conclusions:

• Vitamin A status critically affects the expression of its nuclear receptors and target genes like tTG in the adult brain.
• The developed mouse model is suitable for studying the neurobiological impact of vitamin A.
• This research underscores vitamin A's importance in brain function and gene regulation.