Ligase Pellino3 Regulates Macrophage Action and Survival in Response to VSV Infection in RIG‐I‐Dependent Path

Abstract

Sensing of viral particles and elements that initiate mechanisms of immune response is an intrinsic ability of mammalian cells. Regulatory cytokines and antiviral mediators are released after triggering of complex signaling cascades in response to interaction of pathogen particles with pattern recognition receptors (PRRs) leading to the production of interferons (IFN) and proinflammatory cytokines. Viral RNA in the cytoplasm constitute a potent danger molecule that recognition is performed by RIG-I-like receptors, the most common group of receptors in mammalian cells, capable to recognize a foreign RNA. It is known that the E3 ubiquitin ligase Pellino3 plays an important role in antibacterial and antiviral response, but its involvement in the RLR pathways remains poorly understood. In this study, we investigate the molecular mechanisms of the innate immune response in BMDMs (immortalized macrophages from mouse bone marrow) during VSV infection. Here, we present evidence that the activation of the RIG-I/Pellino3/ERK1/2 pathway in BMDMs is crucial for the protection against VSV. We demonstrate that during infection, viral particles replicate in Pellino3 knockout BMDMs more effectively than in wild-type cells. Increased viral replication resulting in cell lysis and death is aid by impaired synthesis of IFN-I and inflammatory cytokines as a consequence of disturbances in the ERK1/2 pathway regulation.

IFNβ-Induced CXCL10 Chemokine Expression Is Regulated by Pellino3 Ligase in Monocytes and Macrophages

“…Our previous studies have shown that during VSV infection, viral particles replicate in Pellino3-knockout macrophages cell line more effectively than in wild-type cells. Increased viral replication resulting in cell lysis and death was aided by impaired synthesis of type I IFN and inflammatory cytokines production as a consequence of disturbances in the ERK1/2 pathway regulation [ 22 ]. To elucidate the role of Pellino3 in IFN-I-dependent signaling pathways, we created the THP-1 cell line with PELI3 gene knockout ( PELI3 −/− ) using the CRISPR/Cas9 technique.…”

“…Pellino3-regulated signaling pathways have been previously related to MAP kinase pathways [ 22 , 23 ]. Therefore, in the next step, we decided to examine the activation of MAPK kinases: ERK1/2 and p38.…”

“…It is known that Pellino3 negatively regulates IFNβ production in response to the activation of TLR3 and TLR4 [ 20 , 21 ]. Moreover, our recently reported results showed that Pelino3 could function as a positive regulator of the Cxcl10 protein production in the VSV-induced RIG-I-dependent signaling pathway [ 22 ]. Considering the already established view on the role of Pellino3 ubiquitin ligase in the regulation of type I IFN secretion, we asked whether Pellino3 could also affect signaling pathways activated by IFNβ.…”

“…To date, Pellino3 has been reported to be involved in the regulation of p38 MAP kinases [ 23 ]. Furthermore, in our previous research, we have shown that Pellino3 promotes ERK1/2 phosphorylation and IFNβ expression [ 22 ]. However, this was not reflected in our results obtained with IFNβ-treated THP-1 cells because we did not observe any activation of MAP kinases.…”

“…The oxidized form of low-density lipoproteins induces Pellino3- and IRAK1/4-dependent monoubiquitination of TANK protein, resulting in lower IFNβ expression in response to LPS [ 21 ]. Moreover, our recent study demonstrated that Pellino3 regulates VSV-induced CXCL10 production [ 22 ]. However, the effect of Pellino3 on INFβ-activated signaling has not yet been described.…”