Small RNAs and extracellular vesicles in filarial nematodes: From nematode development to diagnostics

Abstract

SummaryParasitic nematodes have evolved sophisticated mechanisms to communicate with their hosts in order to survive and successfully establish an infection. The transfer of RNA within extracellular vesicles (EVs) has recently been described as a mechanism that could contribute to this communication in filarial nematodes. It has been shown that these EVs are loaded with several types of RNAs, including microRNAs, leading to the hypothesis that parasites could actively use these molecules to manipulate host gene expression and to the exciting prospect that these pathways could result in new diagnostic and therapeutic strategies. Here, we review the literature on the diverse RNAi pathways that operate in nematodes and more specifically our current knowledge of extracellular RNA (exRNA) and EVs derived from filarial nematodes in vitro and within their hosts. We further detail some of the issues and questions related to the capacity of RNA-mediated communication to function in parasite-host interactions and the ability of exRNA to enable us to distinguish and detect different nematode parasites in their hosts.

Host-induced gene silencing involves Arabidopsis ESCRT-III pathway for the transfer of dsRNA-derived siRNA

“…sRNA cargo of EVs has been shown for fungi [60], nematodes [75] and plant pathogenic bacteria [76]. In mammalian cells, sRNAs of parasitic origin are transported to host cells via vesicles [77,78].…”

Bacterial outer membrane vesicles at the plant–pathogen interface

“…The rich species diversity of plant pathogenic bacteria offers many avenues for investigation into the way bacteria utilize these tools in specific plant–bacteria interactions. Beyond plant pathogenic bacteria, other microorganisms such as plant pathogenic fungi, nematodes, and also mutualistic microorganisms like rhizobia are likely to secrete extracellular vesicles [25,26]. The role of these extracellular vesicles in pathogenesis and in symbiosis is a fascinating area of research.…”

MicroRNA‐mediated regulation of immune responses to intestinal helminth infections

“…Helminth‐derived miRNAs have been identified in the circulation of their hosts, and trans‐kingdom regulation of mammalian genes by helminth‐derived miRNAs has been reported . Reviewed in greater detail in a companion review to this series, Buck and colleagues identified that H. polygyrus release miRNA‐containing exosomes, which contain distinct miRNAs, relative to miRNAs isolated from the total worm. Furthermore, this paradigm‐changing study identified that H. polygyrus ‐derived miRNA‐containing vesicles were able to inhibit type 2 innate immune responses by suppressing the expression of Il33r and Dusp1 .…”