Non-Specific dsRNA-Mediated Antiviral Response in the Honey Bee

Abstract

Honey bees are essential pollinators of numerous agricultural crops. Since 2006, honey bee populations have suffered considerable annual losses that are partially attributed to Colony Collapse Disorder (CCD). CCD is an unexplained phenomenon that correlates with elevated incidence of pathogens, including RNA viruses. Honey bees are eusocial insects that live in colonies of genetically related individuals that work in concert to gather and store nutrients. Their social organization provides numerous benefits, but also facilitates pathogen transmission between individuals. To investigate honey bee antiviral defense mechanisms, we developed an RNA virus infection model and discovered that administration of dsRNA, regardless of sequence, reduced virus infection. Our results suggest that dsRNA, a viral pathogen associated molecular pattern (PAMP), triggers an antiviral response that controls virus infection in honey bees.

A mutualistic symbiosis between a parasitic mite and a pathogenic virus undermines honey bee immunity and health

“…This working hypothesis is in tune with more recent data indicating that in honey bees from colonies affected by colony collapse disorder, which regularly show high levels of viral infection, the immune response mediated by the RNAi machinery is apparently unaffected (19). Furthermore, immune genes in the Toll pathway are down-regulated in honey bees exposed to Varroa and bearing high DWV loads (12) or challenged with nonspecific dsRNAs (11).…”

“…Separate independent work further corroborated this evidence, showing that viral infection in honey bees interfered with the expression of genes that participate in the Toll pathway (11,12). This finding supports the hypothesis that in honey bees, and more generally in insects, inducible antiviral barriers besides RNAi-mediated mechanisms (11)(12)(13)(14)(15)(16)(17)(18) may have an important role. Indeed, in collapsing colonies, these latter barriers under NF-κB or JAK-STAT control appear to be targeted, whereas the RNAi machinery seems to be unaffected (19).…”

“…That earlier study provided evidence supporting a major role of DWV in the immune suppression process, characterized by a negative impact on a member of the NF-κB protein family (10). Separate independent work further corroborated this evidence, showing that viral infection in honey bees interfered with the expression of genes that participate in the Toll pathway (11,12). This finding supports the hypothesis that in honey bees, and more generally in insects, inducible antiviral barriers besides RNAi-mediated mechanisms (11)(12)(13)(14)(15)(16)(17)(18) may have an important role.…”

Detailed proteome mapping of newly emerged honeybee worker hemolymph and comparison with the red-eye pupal stage

“…They are known to play an important role in insect immunity and development (Evans et al 2006). Some TLRs were found to be involved in insect intracellular signal transduction and the initiation of the insect antimicrobial immune response (Aronstein and Saldivar 2005;Evans et al 2006;Flenniken and Andino 2013). Future observations of toll-like 13 after an immune challenge could demonstrate its function in the pathogen reorganization pathway.…”

Uptake and impact of natural diet-derived small RNA in invertebrates: Implications for ecology and agriculture

“…88 In addition, as RNAi itself is an important component of anti-viral immunity in insects, 149 sRNA and viral infection are likely to influence each other and sRNA function may be heavily influenced by the infection status of the studied insects. 150 Studies in marine shrimp 151 and honey bees 152 demonstrate that in these divergent species, exposure to a wide variety of non-specific sRNA can trigger a non-specific antiviral response. Conversely, viruses, such as Cricket paralysis virus in the fruit fly, 153 often manipulate RNAi machinery leading to decreased function.…”