Multiple sclerosis (MS) is an immune-mediated, demyelinating and neurodegenerative disease of the central nervous system. After traumatic brain injury, it is the leading cause of neurology disability in young adults. Considerable advances have been made in identifying genes involved in MS but the genetic and phenotypic complexity associated with this disease significantly hinders any progress.
A novel class of small ribo nucleic acid (RNA) molecules, microRNAs (miRNAs) has acquired much attention because they regulate the expression of up to 30% of protein-coding genes and may play a pivotal role in the development of many, if not all, complex diseases.
Seven published studies investigated miRNAs from peripheral blood mononuclear cells, CD4+, CD8+ T cell, B lymphocytes, peripheral blood leukocytes, whole blood and brain astrocytes with MS risk. The absence of MS studies investigating plasma miRNA prompted the current investigation of identifying a circulating miRNA signature in MS. We conducted a microarray analysis of over 900 known miRNA transcripts from plasma samples collected from four MS individuals and four sex-aged and ethnicity matched healthy controls.
We identified six plasma miRNA (miR-614, miR-572, miR-648, miR-1826, miR-422a and miR-22) that were significantly up-regulated and one plasma miRNA (miR-1979) that was significantly down-regulated in MS individuals. Both miR-422a and miR-22 have previously been implicated in MS. The present study is the first to show a circulating miRNA signature involved in MS that could serve as a potential prognostic and diagnostic biomarker for MS.
Our genes are what makes use who we are. This genetic code of DNA is read and converted into RNA which is then read to produce amino acids that make up the protiens. Whilst variability can come from different variants of the genetic code for a protien, variation can come after the code has been translated into amino acids and protiens such as adding sugars to the molecule. A new class of regulators of this process is called microRNA. We are beginning to unravel what they do, but we know that they can regulate immune responses and can influence the development of disease in mice as shown in 2011. We too have data on this.
What this microRNA signature means is not clear and alot more samples need to be looked at before one could seriously consider them to be real biomarkers.
However, microRNA can be made and are called small interfering RNA (siRNA) and have the potential to be drug-like molecules to silence protiens. This is a new tool for scientists to control protein function but can be used as therapeutics but thats for another day.