Scientists have discovered a new form of communication between
cells - by sending 'genetic messages'.
The work, by a team at the Medical Research Council's National
Institute for Medical Research (NIMR; now part of the Francis
Crick Institute) and colleagues at Imperial College London,
holds great promise for preventing inflammatory diseases such as
asthma, colitis and autoimmune diseases.
Dr Mark Wilson of NIMR explained: "Cells must communicate with
each other in the body to coordinate responses.
"In this breakthrough study, we have identified that cells send
specific genetic material to other cells, instructing them to stop
proliferating and stop secreting proteins."
The genetic messages are in the form of micro RNAs (miRNAs) -
small strands of RNA that don't code for genes but instead regulate
the expression of other genes. miRNAs regulate gene expression by
binding to messenger RNA molecules (which are direct copies of
genes) and preventing them from being translated into proteins.
The scientists generated 'recipient' cells that were deficient
in miRNAs and grew these cells in the laboratory together with
so-called 'sender' cells, which had miRNAs. They found that the
recipient cells acquired miRNAs from the sender cells, showing that
the genetic messages were being transferred between cells.
The team went on to identify that miRNAs are packaged into
exosomes, small round structures which protect the miRNAs while in
transit, and are delivered directly to inflammatory cells. By
studying a model of colitis, an inflammatory disease affecting the
gut, they found that this form of communication was important for
cells to prevent inflammatory cells from causing intestinal
disease.
Dr Wilson said: "Although these are very early days, if we
identify how these genetic messages are regulated, both from the
sender and by the receiver, we can manipulate this line of
communication by directly targeting cells with miRNAs. This has
implications for preventing inflammatory responses or enhancing
immunity."
The findings also have much wider implications in biology. In
particular, this new mechanism of communication may have
implications for the development of cell-based therapies for cancer
and degenerative disorders such as multiple sclerosis, as well as
inflammatory diseases.
The paper, MicroRNA-Containing T-Regulatory-Cell-Derived Exosomes Suppress
Pathogenic T Helper 1 Cells, is published inImmunity.