Complex interplay between PRRSV-1 genetic diversity, coinfections and antimicrobial use influences performance parameters in post-weaning pigs

Tissue expression of porcine transient receptor potential mucolipin protein channels and their differential responses to porcine reproductive and respiratory syndrome virus infection in vitro

Introduction

Porcine reproductive and respiratory syndrome virus (PRRSV) infection results in a serious disease, posing a huge economic threat to the global swine industry. The transient receptor potential mucolipin proteins (TRPMLs) have been shown to be strongly associated with virus infection and other physiological processes in humans, but their tissue distribution and responses to PRRSV in pigs remain unknown.

Material and Methods

Quantitative reverse-transcription PCR analysis was undertaken to determine the optimal primer for TRPML expression detection and for quantifying that expression individually in different pig tissue samples. Meat Animal Research Center 145 (MARC-145) monkey kidney cells and the TRPML-specific activator mucolipin synthetic agonist 1 (ML-SA1) were used to reveal the relationship between TRPML and PRRSV-2 infection.

Results

The best primers for each TRPML gene used in a fluorescence-based quantitative method were identified and TRPML1 was found to be highly expressed in the kidneys and liver of pigs, while TRPML2 and TRPML3 were observed to be primarily expressed in the kidney and spleen tissues. The expression of TRPML2 was upregulated with the rise in PRRSV-2 infection titre but not the expression of TRPML1 or TRPML3, and ML-SA1 inhibited PRRSV-2 in a dose-dependent manner.

Conclusion

Our research revealed the gene expression of TRPMLs in pigs and identified that TRPML channels may act as key host factors against PRRSV infection, which could lead to new targets for the prevention and treatment of pig infectious diseases.

Research Progress of Porcine Reproductive and Respiratory Syndrome Virus NSP2 Protein

Porcine reproductive and respiratory syndrome virus (PRRSV) is globally prevalent and seriously harms the economic efficiency of pig farming. Because of its immunosuppression and high incidence of mutant recombination, PRRSV poses a great challenge for disease prevention and control. Nonstructural protein 2 (NSP2) is the most variable functional protein in the PRRSV genome and can generate NSP2N and NSP2TF variants due to programmed ribosomal frameshifts. These variants are broad and complex in function and play key roles in numerous aspects of viral protein maturation, viral particle assembly, regulation of immunity, autophagy, apoptosis, cell cycle and cell morphology. In this paper, we review the structural composition, programmed ribosomal frameshift and biological properties of NSP2 to facilitate basic research on PRRSV and to provide theoretical support for disease prevention and control and therapeutic drug development.