Expression Analysis of BDNF Gene and BDNF-AS Long Noncoding RNA in Whole Blood Samples of Multiple Sclerosis Patients: Not Always a Negative Correlation between Them.

Multiple sclerosis (MS) is a chronic inflammatory disorder of the central nervous system (CNS), in which axonal damage is a deteriorative factor. Brain-Derived Neurotrophic Factor (BDNF) is described as a neuronal-survival gene, also capable of exerting pleiotropic effects on the immune cells. Here, we aimed to investigate expression levels of BDNF and its antisense RNA, BDNF-AS, in Iranian MS patients. Our case-control study was based on collecting 50 whole blood samples of relapsing-remitting MS patients and 50 healthy controls. Then, expression analysis of BDNF and BDNF-AS was performed by Real-time quantitative PCR. We found a strong and positive correlation between BDNF and BDNF-AS in MS patients. This is while no significant difference in BDNF and BDNF-AS expression levels was seen between MS patients and controls (p>0.05). A significant and strong positive correlation was found between the expression levels of BDNF-AS and BDNF (r=0.785, p<0.0001). Further, significant positive moderate correlations of BDNF and BDNF-AS with other lncRNAs (GSTT1-AS1 and IFNG-AS1) and genes (TNF and IFNG) were revealed (p<0.0001). Additionally, there was no correlation between the BDNF and BDNF-AS expressions and disease duration, age at onset, and Expanded Disability Status Scale of Kurtzke (EDSS) (p>0.05). BDNF and BDNF-AS expression levels revealed insignificant discrepancies in patients and controls. We found a strong and positive correlation between BDNF and BDNF-AS in MS patients, which is, based on previous studies, a quit novel finding and can be further discussed by future works to unravel its possible application in MS. We suggest evaluation of different leukocytes subsets separately along with large cohort studies comprising a higher number of individuals from different ages to unravel the effects of other possible aspects.