Two microRNAs (miRNAs) thought to regulate immune genes are found at lower levels in the blood of those with MS than in unaffected individuals.
ANZgene investigators found lower expression of two miRNAs — miR-17 and miR-20a — in individuals with relapsing remitting, secondary progressive and primary progressive MS.
Meanwhile, the team’s follow-up experiments indicated that these miRNAs curb the expression of genes involved in activating T cells in the immune system — genes that also tend to be more highly expressed in MS blood samples. As such, they argued, the newly identified miRNAs may prove useful for those looking to come up with new MS treatments.
“In all MS sub-types miR-17 and miR-20a were significantly under-expressed in MS,” corresponding author Rodney Scott, a medical genetics researcher at the University of Newcastle in Australia, and his colleagues wrote. “The same T cell activation genes are also up-regulated in MS whole blood [messenger RNA], suggesting these miRNAs or their analogues may provide useful targets for new therapeutic approaches.”
From the 26 up-regulated miRNAs in MS, the researchers narrowed in on two miRNAs with the most pronounced differences between cases and controls: miR-17 and miR-20a, miRNAs implicated in immune function.
Their results suggest that miR-17 and miR-20a down-regulation is linked to enhanced messenger RNA levels for some of the same T cell related genes that get over-expressed in MS patient blood samples.
Based on these findings, the researchers believe miR-17 and miR-20a might contribute to MS development. And regardless of whether the miRNAs directly contribute to the disease, they added, it may be possible to tweak immune related gene levels in MS by targeting these sorts of regulatory miRNAs.
“Even if the miRNAs under-expressed in MS were not directly contributing to the immune cell signature observed in MS whole blood, the excessive T cell activation signature seen in MS and other autoimmune diseases suggest agents which can reduce this activity may be therapeutically beneficial,” the team concluded.
Source: GenomeWeb (12/08/10)