Myotonic dystrophy type 1 (DM1) is the most common form of adult-onset
muscular dystrophy, which is characterised by progressive muscle wasting
and the discovery of reliable blood-based biomarkers could be useful for
the disease progress monitoring. There have been some reports showing
that the presence of specific miRNAs in blood correlates with DM1. In
one of these, our group identified four muscle-specific miRNAs, miR-1,
miR-133a, miR-133b and miR-206, which correlated with the progression of
muscle wasting observed in DM1 patients. The levels of the four
muscle-specific miRNAs were elevated in the serum of DM1 patients
compared to healthy participants and were also elevated in the serum of
progressive muscle wasting DM1 patients compared to disease-stable DM1
patients. The aim of this work was to characterise the ontology of these
four muscle-specific miRNAs in the blood circulation of DM1 patients.
Here we show that the four muscle-specific miRNAs are encapsulated
within exosomes isolated from DM1 patients. Our results show for the
first time, the presence of miRNAs encapsulated within exosomes in blood
circulation of DM1 patients. More interestingly, the levels of the four
exosomal muscle-specific miRNAs are associated with the progression of
muscle wasting in DM1 patients. We propose that exosomal muscle-specific
miRNAs may be useful molecular biomarkers for monitoring the progress of
muscle wasting in DM1 patients. There has been a growing interest
regarding the clinical applications of exosomes and their role in
prognosis and therapy of various diseases and the above results
contribute towards this way