A novel heat-shock protein inducer triggers heat shock protein 70 production and protects Artemia franciscana nauplii against abiotic stressors

Abstract

Induction of heat shock protein 70 (Hsp 70) is important in the tolerance to subsequent deleterious environmental stresses. It would therefore be of great benefit to develop non-toxic Hsp70-inducing compounds that are able to induce Hsp70 in advance, for animals which are subjected to various environmental stresses. This study aimed to investigate whether Pro-Tex®, a soluble version of Tex-OE® a chaperone-stimulating factor isolated from the prickly pear cactus (Opuntia ficus indica), could manipulate Hsp70 expression in a gnotobiotically cultured brine shrimp Artemia franciscana and subsequently protect against abiotic stressors. Results showed that Tex-OE® enhanced Hsp70 expression in a dose- and time-dependent manner in Artemia. In addition, pretreatment of Artemia with Tex-OE® (152ppb) for 1h protected the shrimp against thermal challenge. Interestingly, the expression level of Hsp70 coincided well with the extent of protection against thermal challenge, suggesting that the protective effect of the compound is mediated by Hsp70 induction. Results also demonstrated that Tex-OE® can function in synergy with a non-lethal heat shock (37°C for 30min followed by 6h recovery) conferring maximum protection to Artemia against thermal and hypersalinity stresses at either optimal (152ppb) or sub-optimal (76ppb) dose. From these results, it is suggested that Tex-OE® is a potential inducer of Hsp70 and in the presence or absence of a bona fide stress, it could be an ideal candidate for use as an anti-stressor during various aquaculture practices.