Images were analyzed using ImageJ (NIH)

Images were analyzed using ImageJ (NIH). mutation in CR6 (CR6E94D) does not prevent persistence, indicating that additional differences within NS1 are important (Nice et al., 2013). NS1CR6 enables contamination of intestinal epithelial cells (IECs), the cellular reservoir of persistent enteric infection, but the molecular mechanism of NS1 is usually unknown and remains an area of ongoing research (Lee et al., 2017b). VP1 has been more extensively studied and was recently shown to bind CD300lf, a cellular receptor necessary for entry (Haga et al., 2016; Orchard et al., 2016). Strains CW3 and CR6 both require CD300lf for entry, and, therefore, the mechanism of differential tissue tropism for these strains is usually CD300lf-independent. Systemic replication determined by VP1 of CW3 (VP1CW3) correlates with enhanced expression of type I interferon (IFN) and type III IFN genes at initial sites of MNV replication (Nice et al., 2015). These IFN families play complementary roles in the antiviral host response: type I IFN controls systemic MNV replication in myeloid-lineage cells, whereas type III IFN controls replication and persistence in IECs (Baldridge et al., 2017; Lee et al., 2017b; Nice et al., 2015). Consistent with the role of type III IFN in protecting IECs, persistence of CW3D94E is usually promoted by replacing VP1CW3 with VP1CR6 (CW3D94E-VP1CR6), which reduces induction of type III IFN (Nice et al., 2015). Thus, an early difference in IFN expression Rabbit Polyclonal to APOL2 determined by VP1 can change the outcome of MNV contamination. The actions of IFNs are many-fold, including the induction of cell-intrinsic effector molecules and secretion of chemokines to recruit effector cells. Activation of these effector cells following their recruitment is also regulated by IFNs. Neutrophils and Ly6Chigh inflammatory monocytes (IMs) are among the first responders to contamination Ccapable of responding Daminozide to and producing IFNs. Recruitment of IMs and neutrophils is beneficial for clearance of bacteria and fungi (Dale et al., 2008), but can be either beneficial or detrimental for clearance of viruses (Channappanavar et al., 2016; Conrady et al., 2013; Galani et al., 2017; Lee et al., 2017a; Sammicheli et al., 2016; Uyangaa et al., 2015). Like other myeloid cells, IMs and neutrophils express using LysM-cre or CD11c-cre results in poor control of systemic viral replication (Nice et al., 2016; Thackray et al., 2012). CD11c-cre targets recombination in 5C70% of IM and neutrophil populations, in addition to its widely recognized targeting of dendritic cells (Abram et al., 2014), In this study, we characterize the host cytokine response to MNV contamination determined by VP1 and define its impact on systemic viral replication. Using a panel of VP1 chimeric viruses, we find that contamination of cells with VP1CW3 strains results in increased lytic cell death relative to VP1CR6 strains. Furthermore, contamination with VP1CW3 strains elicits increased release of inflammatory cytokines and messenger RNA (Fig. 1F). Daminozide These data indicate that VP1CW3 increases inflammatory cytokine release, particularly IL-1, from infected cells. Open in a separate window Physique 1. The MNV capsid determines lytic cell death and inflammatory cytokine release.ACB. Diagram of genomes and structures of capsid Daminozide chimeric viruses used in this study. Strains with the VP1 gene (highlighted region) of CW3 (blue) or CR6 (red) have otherwise identical CW3D94E (A) or CR6 (B) genomes as depicted. CCI. WT (CCF) or messenger RNA (Fig. 1I). These data demonstrate that this VP1CW3-dependent increase in IL-1 protein.