Zebrafish C-reactive protein isoforms inhibit SVCV replication by blocking autophagy through interactions with cell membrane cholesterol

Abstract

Phosphorylcholine works not only as a pathogen-associated molecular pattern (PAMP) 10,18-20 , but also as a danger-associated molecular pattern (DAMP) 18,21-24. This phosphorylcholine-binding site of the soluble CRP is also involved in interactions with, for instance, oxidized low-density lipoprotein (LDL) 21 , nuclear materials (such as chromatin, histones, small nuclear ribonucleoproteins) 25,26 , and other compounds that may not contain phosphorylcholine but are abundant in bacteria 27 , fungi 28,29 and parasites 30,31. In mammals, CRPs are usually triggered during both viral and bacterial infections 32 , although associated serum CRP level increases are more characteristic of bacterial infections, during which they increase by 3-fold logs, while viruses induce lower but significant 10 1 serum CRP levels 2,32,33. Furthermore, the few existing studies that have analysed C-reactive-like protein (CRP) levels in fish show moderate serum level increases in response to both bacterial and viral infections, suggesting an antiviral effect for CRPs 34-36. For example, in common carp (Cyprinus carpio), the serum CRP levels increase up to 2-, 6-and 10-fold in response to Aeromonas salmonicida 37 , Aeromonas hydrophila 34 and cyprinid herpesvirus-3 (CyHV-3) 35 infections, respectively. Further positive correlations between CRP levels and viral infections have been established in fish by transcriptional analysis. For instance, significant upregulation of crp gene expression in several immune-and non-immune-related tissues of diverse fish species has been revealed in response to viruses such as CyHV-3 35 , red seabream iridovirus (RSIV) 38-40 , viral haemorrhagic septicaemia virus (VHSV) 41,42 and spring viraemia of carp virus (SVCV) 42,43. Similarly, higher transcriptional expression of crp genes was observed in common carp treated with polyinosinic:polycytidylic acid (polyI:C, a compound that mimics viral dsRNA) 36 , in DNA-vaccinated rainbow trout (Oncorhynchus mykiss) 44 and zebrafish (Danio rerio) embryos microinjected with an expression plasmid encoding the il6 gene 42 , a cytokine that is upregulated in response to viral infections in humans 45. In this sense, our recent findings show that all previously identified zebrafish CRP1-7 isoforms 46 confer isoform-dependent anti-SVCV protection in vitro and in vivo 47 and exert unexpected anti-SVCV synergistic effects 47 with 25-hydroxycholesterol (25-HOC) 48. Recombinant CRP from tongue sole (Cynoglossus semilaevis) has also been reported to enhance host resistance to RSIV infection when intraperitoneally (i.p.) co-injected with the virus inoculum 40. However, despite the great relevance for evolutionary immunology and therapeutic potential of CRPs, the underlying mechanisms for CRP antiviral effects are not yet known. The present work has been focused on these mechanistic aspects. Results CRP1-7 anti-SVCV activity targets host cells rather than the virus. Our previous studies showed that the treatment with the supernatant from epithelioma papulosum cyprinid (EPC) cells th...

Characterization of the lipidomic profile of BmN cells in response to Bombyx mori cytoplasmic polyhedrosis virus infection

“…Glycerophospholipid metabolism is involved in the biosynthesis of PC and PE. An increasing number of studies have shown that disorders of glycerophospholipid metabolism in cells can lead to onset of diseases ( Bello-Perez et al, 2020 ; Wang et al, 2020 ). In this study, the metabolism of glycerophospholipids, especiallyPC(38:2) and PE(36:1) were found to be the most enriched pathway during BmCPV infection, indicating that glycerophospholipid metabolism may be crucial for the pathogenesis of BmCPV.…”

“…Apolipoprotein A-I binding protein is an intrinsic factor that suppresses human immunodeficiency virus (HIV) replication ( Dubrovsky et al, 2020 ). Zebrafish C-reactive protein-like protein inhibits spring viraemia of carp rhabdovirus replication by causing alterations of cholesterol ratios in the host cellular membranes ( Bello-Perez et al, 2020 ). Lipids have also been shown to play important roles in the replication of coxsackievirus B3 ( Wang et al, 2020 ).…”

Potential aquatic environmental risks of trifloxystrobin: Enhancement of virus susceptibility in zebrafish through initiation of autophagy

“…PCR analysis was amplified as follows: 95 °C for 30 s, denaturation for 40 cycles at 95 °C for 15 s, and annealing at 60 °C for 60 s. To assess the specificity of each amplicon, melt curve analysis was also performed at the end of each thermal profile. The sequences of primers are listed in Table 1 ( Bello-Perez et al, 2020 ; Gotesman et al, 2015 ; Varela et al, 2014 ). Each sample was run in triplicate and the β-actin gene was used as an internal control for normalization.…”

Compilation of antiviral treatments and strategies to fight fish viruses

“…Recent observations have suggested that the anti‐SVCV activity mediated by zebrafish Crp proteins is related to their ability to inhibit the autophagic process (Belló‐Pérez et al . 2020), a mechanism that is known to be essential for SVCV replication (Liu et al . 2015).…”