How Our Other Genome Controls Our Epi-Genome

Eukaryotes and prokaryotes produce extracellular nanovescicles that contain RNAs and other molecules that they exploit to communicate. Recently, inter-kingdom crosstalk was demonstrated between humans and bacteria through fecal microRNAs. We suggest here how bacteria interact with humans via RNAs within membrane vesicles to alter our epigenome, thus filling the gap and closing the circle. At the same time, there are indications that there could be a wider inter-kingdom communication network that might encompass all known kingdoms. Now that the connection with our other genome has been established, we also should begin to explore the 'social' network that we have around us. The first evidence that outer-membrane vesicles (OMVs) are produced by Escherichia coli dates from 1976. After 40 years, bioengineered OMVs are considered today to be promising innovative vectors for drug delivery and cancer therapy.The first evidence of inter-kingdom crosstalk between humans and gut microbiota through microRNAs that are contained in extracellular vesicles (EVs) was reported earlier this year.Many bacterial small RNAs that are contained in OMVs align to histone marks in the human genome. We hypothesized that they may act as long non-coding RNAs, thus regulating our epigenome.We still do not know how many diseases or pathological conditions may be caused by the interplay between bacterial OMVs and the human genome.