Non-cytopathic bovine viral diarrhea virus 2 induce autophagy in MDBK cell

Abstract

Abstract Objective Bovine viral diarrhea virus (BVDV) is classified into two distinct species, BVDV1 and BVDV2. Both species consist of two biotypes, cytopathic (cp) and non-cytopathic (ncp). Autophagy is an essential control process by which cells degrade unnecessary or dysfunctional cellular components or organelles in the cytoplasm. In this study, we explored autophagy activity in ncp BVDV2-infected MDBK cells. Materials and methods Ncp BVDV 2 (12F001) strain was cultured in MDBK cell and titration of the 50% tissue culture infective dose (TCID50) was conducted using the Kärber method. Transfection with GFP-LC3 was performed using the LipofectamineTM 2000 reagent. MDBK cells (8′105) were seeded in 6-well plates, infected with ncp BVDV2 or treated with rapamycin or DMSO, and then incubated. Subsequently, cells were used for western blot for LC3B, p62/SQSTM1, ATG14, and β-Actin. Results Our results showed that LC3 protein expression levels were increased in ncp BVDV2-infected MDBK cells by western blot and confocal microscopy. This expression was high in rapamycin-treated cells, followed by ncp BVDV2 infection, and DMSO treatment. We determined autophagy activity in ncp BVDV2-infected MDBK cells by assessing the protein levels of SQSTM/p62, LC3 and ATG14 by western blot. The decreased levels of SQSTM/p62 were accompanied by an enhanced expression of LC3 and ATG14 in ncp BVDV2-infected MDBK cells. Conclusion These results suggest that ncp BVDV 2 infection activate autophagy in MDBK cells. We conclude that autophagy may be linked to the establishment of persistent infection through virus survival. Thus, further studies should be needed to determine the association between autophagy and virus replication.