Consideration of the role of MALAT1 long noncoding RNA and catalytic component of RNA-induced silencing complex (Argonaute 2, AGO2) in autism spectrum disorders: Yes, or no?

Autism spectrum disorders (ASD) are complex neurodevelopmental impairments in which dysregulation of long noncoding RNAs (lncRNAs) has been indicated. LncRNAs tend to play role in constituting comprehensive networks of ribonucleoprotein complexes including argonautes. Here, we aimed to study the expressions of MALAT1, a highly conserved lncRNA, and AGO2 gene, encoding the catalytic component of the RNA-induced silencing complex (RISC), in ASD patients. In this case-control study, peripheral whole blood samples were gathered from 30 ASD patients and 41 healthy controls and expression level of genes were matured by quantitative Taq-Man real-time PCR. we found an increase in MALAT1 expression, which was statistically insignificant. Moreover, the AGO2 expression revealed a decrease that did not reach a level of significance. There was a significant and direct correlation between expression levels of MALAT1 and AGO2 (r = 0.427, P < 0.0001). Eventually, MALAT1 and AGO2 correlations with patients' age did not show a significant difference. These findings provide clues that although we have indicated a significant direct correlation between MALAT1 lncRNA and AGO2, implying their interactive network, there should be a reconsideration regarding their role in ASD development based on whole blood samples because the altered expressions were not strong enough to be significant. Further investigations employing larger sample sizes and specific leukocytes subsets separately could profoundly strengthen these findings.