Abnormalities in trehalose homeostasis reduce autophagy, antioxidant and response to air exposure stress in Eriocheir sinensis

Abstract

Trehalose, a key carbohydrate in crustaceans and insects, is important in enhancing stress resistance. However, its regulatory mechanisms and functions in Chinese mitten crabs (Eriocheir sinensis) remain unclear. This study was designed to explore the regulation mechanisms of trehalose anabolism by synthesizing dsRNA interference fragments to target trehalose-6-phosphate synthase (TPS) and trehalose hydrolase (TREH) genes, investigating the effects of endogenous trehalose anabolism, antioxidant function, and autophagy in crabs under air exposure stress (AES). First, dsRNAs were synthesized, and interference fragments (EGFP, dsTPS1, and dsTREH2) and the optimal interference duration (48 h) were screened by in vitro culture. Further in vivo experiments demonstrated that interference with TPS and TREH genes led to abnormal trehalose anabolism in crabs subjected to AES; following interference, the expression of TPS gene was significantly down-regulated, while that of trehalose transporters (TRET) genes was significantly up-regulated; in the hepatopancreas, the levels of trehalose and glucose (Glu) were notably increased, whereas their levels in the hemolymph were significantly decreased. Abnormalities in trehalose homeostasis led to down-regulated expression of autophagy genes (ATG4B, ATG7, ATG13, Beclin1) and its activation pathway, MAPK signaling pathway genes (ERK, JNK, p38); this was accompanied by a decrease in p38 protein level, which ultimately led to decreased antioxidant capacity, increased vacuolated cells, and disturbed cellular arrangement in hepatopancreatic tissues of crabs under AES; there was an up-regulation of the expression of genes such as catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-PX), which resulted in significant increase in the cumulative mortality rates.