What is the research about?

Children with Rett syndrome lose multiple thinking, learning, and movement abilities beginning at 6 to 18 months of age.  As they get older, they are often unable to learn new skills. They have problems with digestion, and with the heart, muscles, and bones. This study looked at whether or not the immune system could play a role in these symptoms.


What did the researchers do?

Scientists looked at mouse cells with the genetic mutation associated with Rett Syndrome (the MeCP2 gene). They then looked at the activities of macrophages in these cells. Macrophages are termed the 'big eaters' of the immune system. They live in every tissue of the body, where they clear up the debris from tissue damage or infection. Although they remove disease-causing cells, they also play a role in creating inflammation, and in degenerative diseases.


What did the researchers find?

The researchers found that the genes responsible for making the macrophages were not performing their normal functions. Instead, they were making the disease-causing process worse. The researchers likened the activity to “being in a car with only a gas pedal” -- there is nothing to stop the process, as would usually happen in the course of daily life. The problem with the macrophages is that they are too sensitive to the signals and stimuli they receive in everyday situations. The macrophages end up causing damage to tissue, instead of protecting it. In the process, the macrophages, themselves, then die off.  The authors believe that a treatment for this oversensitivity could be found and that it might slow down the progression of Rett syndrome.


Take home message

This study found evidence that the immune system is involved in the progression of the symptoms of Rett syndrome.  The researchers believe it is possible that the oversensitivity of the macrophages in cells with the MeCP2 mutation can be targeted for treatment.


Notes

NOTE: The original Research Report was written by J. C. Cronk, and associates, and was published in Immunity. 2015.