Small Luggage for a Long Journey: Transfer of Vesicle-Enclosed Small RNA in Interspecies Communication

Abstract

In the evolutionary arms race, symbionts have evolved means to modulate each other's physiology, oftentimes through the dissemination of biological signals. Beyond small molecules and proteins, recent evidence shows that small RNA molecules are transferred between organisms and transmit functional RNA interference signals across biological species. However, the mechanisms through which specific RNAs involved in cross-species communication are sorted for secretion and protected from degradation in the environment remain largely enigmatic. Over the last decade, extracellular vesicles have emerged as prominent vehicles of biological signals. They can stabilize specific RNA transcripts in biological fluids and selectively deliver them to recipient cells. Here, we review examples of small RNA transfers between plants and bacterial, fungal, and animal symbionts. We also discuss the transmission of RNA interference signals from intestinal cells to populations of the gut microbiota, along with its roles in intestinal homeostasis. We suggest that extracellular vesicles may contribute to inter-species crosstalk mediated by small RNA. We review the mechanisms of RNA sorting to extracellular vesicles and evaluate their relevance in cross-species communication by discussing conservation, stability, stoichiometry, and co-occurrence of vesicles with alternative communication vehicles.

In vitro resynthesis of lichenization reveals the genetic background of symbiosis-specific fungal-algal interaction in Usnea hakonensis.

“…Expression of genes involved in sphingolipid and phospholipid biosynthesis was up-regulated in the symbiotic states (Uhk_003277, Uhk_017380, and Uhk_017885). Sphingolipids and phospholipids are constitutive lipids of membrane microdomains and extracellular vesicles respectively (29,30,67,68), both reported to be involved in the communication between symbiotic partners (69)(70)(71)(72)(73). The up-regulated expression of the genes involved in these fungal lipid metabolisms might suggest that lipids are not merely the components of the hydrophobic layer but also used as fungal tools to communicate with algal partners (Figure 2e).…”

In vitro resynthesis of lichenization reveals the genetic background of symbiosis-specific fungal-algal interaction in Usnea hakonensis.

“…Expression of genes involved in sphingolipid and phospholipid biosynthesis were up-regulated in the symbiotic states (Uhk_003277, Uhk_017380, and Uhk_017885). Sphingolipids and phospholipids are constitutive lipids of membrane microdomains and extracellular vesicles respectively (29,30,67,68), both reported to be involved in the communication between symbiotic partners (69)(70)(71)(72)(73). The up-regulated expression of the genes involved in these fungal lipid metabolisms might suggest that lipids are not merely the components of the hydrophobic layer but also used as fungal tools to communicate with algal partners (Figure 2e).…”

Lymphoma diagnostics: getting more from less

“…Additionally, exosomes may be taken up by other cells and the contents may influence biology at distance (Edgar, ). Interestingly, the circulating vesicles have been shown to contain nucleic acid in the form of DNA, mRNA and microRNA (miRNA), which may have important biological effects on cells that take up this material (Lefebvre & Lecuyer, ). A recent study found that Epstein–Barr virus (EBV)‐infected cells release exosomes that can influence lymphoproliferation in uninfected cells (Higuchi et al , ).…”