Pre-existent Hsp72 contributes to glutamine-induced hepatic hsp72 gene activation during heat shock recovery period in rat

Abstract

Scope: Functional maintenance of liver is very important at all times for personal health. Hsp induction is associated with the protection of the organ. Glutamine, a nutrient inducer of Hsps, enhances cellular survival via Hsp72 induction in several organs, but not in the liver. The present study showed a novel approach to facilitate glutamine-induced hepatic Hsp72 synthesis and its possible mechanisms were discussed.

Methods and results: Sprague-Dawley rats were used as the experimental animals and the livers were the targets. Glutamine was administered via tail-vein injection, and its effects on hsp72 gene activation, including Hsp72 expression, heat shock factor-1 (HSF-1) phosphorylation and DNA-binding activation, were evaluated. The results showed that Hsp72 itself played a critical role in glutamine-induced hepatic Hsp72 synthesis during HS recovery period in a dose-dependent manner of preexistent Hsp72. The peak value of HSF-1 phosphorylation, HSF-1 DNA-binding activity, hsp72 mRNA accumulation, and Hsp72 synthesis was detected at 8 h after glutamine administration.

Conclusion: Glutamine switched on alteration pathway in inducing hsp72 gene activation. The existence of Hsp72 plays a critical role in the reactivation of hsp72 gene. Glutamine sustained the induction of intracellular Hsp72, which could be beneficial in protecting the liver from various injuries.