The Modulation of Immune Responses in Tilapinevirus tilapiae-Infected Fish Cells through MAPK/ERK Signalling

Abstract

Tilapia lake virus (TiLV) is a novel RNA virus that has been causing substantial economic losses across the global tilapia industry. Despite extensive research on potential vaccines and disease control methods, the understanding of this viral infection and the associated host cell responses remains incomplete. In this study, the involvement of the mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) pathway in the early stages of TiLV infection was investigated. The results showed a distinct pattern of ERK phosphorylation (p-ERK) upon TiLV infection in two fish cell lines, E-11 and TiB. Specifically, the p-ERK levels in the TiB cells decreased substantially, while the p-ERK levels in the E-11 cells remained constant. Interestingly, a large number of cytopathic effects were observed in the infected E-11 cells but none in the infected TiB cells. Furthermore, when p-ERK was suppressed using the inhibitor PD0325901, a significant reduction in the TiLV load and decrease in the mx and rsad2 gene expression levels were observed in the TiB cells in days 1–7 following infection. These findings highlight the role of the MAPK/ERK signalling pathway and provide new insights into the cellular mechanisms during TiLV infection that could be useful in developing new strategies to control this virus.

Proteomic and phosphoproteomic profilings reveal distinct cellular responses during Tilapinevirus tilapiae entry and replication

“…Interestingly, in addition to the observed cellular damage, our findings revealed variations in the infection dynamics and TiLV replication across different fish cells. Notably, the TiLV load in the E-11 cells was higher than that in the RHTiB cells at 24 hpi, which is consistent with the results of a previous study 14 . We propose that while TiLV is capable of propagating in recently established RHTiB cells, these cells are less susceptible to TiLV compared to well-established E-11 cells.…”

“…The E-11 and RHTiB cells were assessed for TiLV at 10 min post-infection (mpi), 30 mpi, 1 h postinfection (hpi), 3 hpi, 6 hpi, and 24 hpi using a quantitative reverse transcription polymerase chain reaction (RT-qPCR). Initially, total RNA extraction from the collected cell lysates was conducted as described by Lertwanakarn et al 14 Briefly, the cell lysates were mixed with GENEzol® reagent (Geneaid Biotech, Taipei, Taiwan) and chloroform (Sigma-Aldrich, Saint-Louis, USA) and centrifuged at 15,000 × g at 4 °C. The supernatant was collected and treated with DNase I (Thermo Fisher Scientific, Carlsbad, USA), followed by 2-propanol (Merck, Darmstadt, Germany), and stored at −20 °C for 2 h. After thawing and centrifugation, the pellets were washed with ethanol and air-dried.…”

“…Despite its remarkable economic impact, the molecular mechanisms underlying host-virus interactions during TiLV infection remain poorly understood. Current research on the pathogenesis of TiLV infection is primarily focused on the viral replication mechanisms, host immune responses, and subcellular processes that occur during viral infection [11][12][13][14] . For example, a study by Piewbang et al 15 demonstrated the presence of viral RNA in various tissues, which indicated the multi-tissue tropisms of TiLV.…”

Tilapia lake virus causes mitochondrial damage: a proposed mechanism that leads to extensive death in fish cells

“…Similarly, TEM studies revealed the presence of TiLV particles in the liver of infected fish, in both laboratory and natural settings, although the specific mechanism of cell entry remains undetermined ( Del-Pozo et al, 2017 ; Tattiyapong, Dachavichitlead & Surachetpong, 2017 ). Recent reports demonstrated that TiLV enters tilapia cells via a cholesterol-dependent, dynamin-mediated endocytosis mechanism ( Abu Rass et al, 2022 ) and MAPK-dependent signaling pathway ( Lertwanakarn et al, 2023 ). In our study, we observed notable changes in the intracellular structure and organelles of infected E-11 cells within 1 dpi.…”

Knowns and unknowns of TiLV-associated neuronal disease

“…This suggests that TiLV might cross the BBB in a process dependent on actin and microtubule polymerization, both known to be involved in the formation of macropinosome ruffles. Moreover, similar to HIV-1, ERK/MAPK signalling participates in TiLV propagation [ 93 ].…”