Porcine epidemic diarrhea virus M protein blocks cell cycle progression at S-phase and its subcellular localization in the porcine intestinal epithelial cells.

Abstract

Porcine epidemic diarrhea (PED) caused by virulent strains of porcine epidemic diarrhea virus (PEDV) is ahighly contagious enteric disease of swine characterized by severe enteritis, vomiting, and watery diarrhea. This study investigates the subcellular localization and function of PEDV M protein through examination of its effects on cell growth, cell cycle progression, and interleukin 8 (IL-8) expression. Our results revealed that the PEDV M protein is localized throughout the cytoplasm. The M protein altered swine intestinal epithelial cell line (IEC) growth and induced cell cycle arrest at the S-phase via the cyclin Apathway. The S-phase arrest is associated with adecrease in level of cyclin A. Furthermore, our results revealed that the M protein of PEDV does not induce endoplasmic reticulum (ER) stress and does not activate NF-κB which is responsible for IL-8 and Bcl-2 expression. This is the first report to demonstrate that the PEDV M protein is localized in the whole cell and induces cell cycle arrest at the S-phase. This study provides novel findings in the function of M proteins of PEDV.