Activity of cytokines and regulation of signaling pathways
As the invasions, viruses should have the capability to adjust the
activities of cytokines and regulate intracellular signaling pathways of
the host cells following invasion, thereby facilitating the replication
and proliferation of viral particles. Indeed, pronounced changes of the
expression of numerous proteins occur, as revealed by proteomic analysis
in PEDV infected Vero cells. Moreover, these altered proteins are
identified to participated in various biologic processes such as
apoptosis, signal transduction and stress response (Z. S et al., 2015).
For instance, PEDV induced apoptosis is mainly mediated by the
activation of caspase-dependent mitochondrial apoptotic inducible factor
(AIF) signaling pathway in target cells (K. Y & C, 2014). Likewise,
PEDV infection can also activate the components of intracellular MAPK
signaling pathway including ERK (extracellular signaling-regulated
kinase), p38 MAPK and JNK (c-Jun N-terminal kinase) (K. Y & C, 2015).
In addition, PEDV infection induced endoplasmic reticulum (ER) stress
response and the activation of NF-κB signaling, have been found and
described as well (W. K et al., 2012; Xu et al., 2013). Therefore, it is
reasonable and logical to believe that the PEDV induced alterations of
protein expression, cellular response and signaling collectively create
a conducive microenvironment for its proliferation in the host cells.