RNAi-mediated silencing of Trichinella spiralis glutaminase results in reduced muscle larval infectivity.

Trichinella spiralis is an important foodborne parasitic nematode distributed worldwide that infects humans and animals. Glutaminase (GLS) is an important gene in the glutamine-dependent acid resistance (AR) system; however, its role in T. spiralis muscle larvae (ML) remains unclear. The present study aimed to characterize T. spiralis GLS (TsGLS) and assess its function in T. spiralis ML AR both in vitro and in vivo using RNA interference. The results indicated that native TsGLS (72 kDa) was recognized by anti-rTsGLS serum at the muscle larvae stage; moreover, an immunofluorescence assay confirmed that TsGLS was located in the epidermis of ML. After silencing the TsGLS gene, the relative expression of TsGLS mRNA and the survival rate of T. spiralis ML were reduced by 60.11% and 16.55%, respectively, compared to those in the PBS and control groups. In vivo AR assays revealed that the worm numbers at 7 and 35 days post-infection (dpi) decreased by 61.64% and 66.71%, respectively, compared to those in the PBS group. The relative expression of TsGLS mRNA in F generation T. spiralis ML was reduced by 42.52%, compared to that in the PBS group. To the best of our knowledge, this is the first study to report the presence of the glutamine-dependent AR system in T. spiralis. Our results indicate that TsGLS plays a crucial role in the T. spiralis AR system; thus, it could be used as a potential candidate target molecule for producing vaccines against T. spiralis infection.