We’ve all had things come back and haunt us—like our high school yearbook picture (the horror!). Now, researchers in Germany say they hypothesize that the same thing could happen with a chromosome 19 miRNA cluster. These miRNAs appear to dampen a mother’s immune response to a developing fetus, but the researchers think that this “immunomodulatory” function may come back later in life to spur on thyroid nodules, autoimmune disorders, and maybe even cancer.
Previous research has shown that structural rearrangements of chromosomal band 19q13 are common in thyroid adenomas and adenomatous goiters. The important region was narrowed down to the chromosome 19 microRNA cluster (C19MC), the largest human miRNA cluster.
Normally, only embryonic stem cells and then the placenta express these miRNAs during development in utero. The miRNAs wind up getting kicked out of the placenta in vesicles called exosomes. These packages of miRNAs can suppress T-cell signaling of the immune system, possibly preventing the fetus from being rejected as a foreign growth.
The German group hypothesizes that these same miRNAs, packaged in exosomes, come back later in life to protect thyroid goiter and adenoma cells from immune attack. They say that this region of chromosome 19 also has been implicated in various cancers.
The team proposes some experimental directions. Then, they wrap up by saying that if the hypothesis is true, it could hold lots of promise for the clinic, including treatments for autoimmune diseases, the prevention of transplant rejection, and cancers.
Check out the full hypothesis at Molecular Cytogenetics, May 2012.