Quorum Sensing Peptides and Their Interactions with the Host

Quorum sensing peptides are signalling molecules that are produced by mainly Gram-positive bacteria. They can be categorized into different groups, based on both chemical and microbiological characteristics. Although quorum sensing peptides were originally found as intra-species communication tools, recent evidence indicates that these peptides also interact with host cells, thereby possibly intervening in the microbiome-host interactions observed in different diseases. In colorectal cancer for example, an E. faecium quorum sensing peptide was found to promote metastasis of the tumor cells in vivo. Also in neurodegenerative disorders, quorum sensing peptides can play a role: in vitro interactions between the peptides and brain cells were determined, resulting in the production of pro-inflammatory cytokines. Finally, also a decreased viability and increased inflammation of muscle cells was observed after quorum sensing peptide treatment; these peptides could thus also be involved in muscle wasting diseases like sarcopenia. Awaiting further in vivo confirmatory results on the biological effects of the quorum sensing peptides, these results already give a first indication of the (additional) causative role of quorum sensing peptides in the observed microbiome-host crosstalk phenomena. This may eventually lead to the development of novel (bio-)therapeutics.