Investigation of miRNA expression levels in peripheral blood of males with cocaine use disorder

Many animal and cell studies have shown that microRNAs play important roles in the development and progression of drug addictions, including addiction to methamphetamine, cocaine, alcohol, and heroin. In the international literature, it is observed that there are a limited number of scientific studies investigating the effect of cocaine use disorder on microRNA level in human peripheral blood. However, the role of microRNAs as potential biomarkers in peripheral blood on cocaine addiction has not yet been discovered in our country. In this context, this study detected changes in the expression of some microRNAs (miR-9-5p, miR-26b-5p, miR-132-3p, and miR-134-5p) in the peripheral whole blood of cocaine addicts, which may play a role in the regulation of cocaine addiction aimed to identify candidate microRNAs. According to the international literature, this study is the first to analyze relevant microRNAs in the peripheral blood of cocaine addicted humans. In this study, 12 male individuals who were addicted to cocaine constituted the addict group, 11 individuals who were being treated for cocaine addiction constituted the treatment group and 16 healthy individuals without any substance addiction constituted the control group. Blood samples of dependent and treatment group individuals were collected from volunteers who applied to the Anatolia Clinic of Balıklı Rum Hospital for treatment and agreed to participate in the study. After isolation of total RNA from peripheral blood samples obtained from individuals, cDNA synthesis was performed with reverse transcriptase. The change in the expression of microRNAs was determined by the quantitative real-time PCR method. The ''fold change'' value in microRNA expression levels was determined according to 2- ΔΔCT. In statistical analyses, analyzes were made based on ΔCt values for the expression of microRNAs. One-way ANOVA test was used to analyze whether there was a difference in ΔCt values of candidate microRNAs between dependent, treatment and control groups. LSD test or Tamhane's T2 test was used as post-hoc test. In all analyses, p<0.05 was considered statistically significant. ROC analysis was used to assess the diagnostic adequacy of peripheral blood microRNAs. At the end of the study, it was determined that there was a significant difference between the dependent group and the treatment group only in terms of ΔCt values of miR-132-3p (p=0.003) and miR-134-5p (p=0.020). There was a significant difference between the dependent group and the treatment group in terms of ΔCt values of miR-9-5p (p=0.012), miR-26b-5p (0.009), miR-132-3p (p=0.026) and miR-134-5p (p=0.023), respectively. There was a significant difference between the treatment group and the control group only in terms of ΔCt values of miR-9-5p (p=0.019) and miR-26b-5p (0.024). When the ROC curve analyses were compared with the control group, the AUC value for miR-132-3p was found to be 0.778 and the AUC value for miR-134-5p was found to be 0.744 in the dependent group. These results suggest that miR-132-3p and miR-134-5p can be used as effective diagnostic parameters in individuals with cocaine addiction. With the results obtained in this study, it is thought that if similar findings are demonstrated by other studies in the future, microRNAs that may play a role in the pathology of cocaine addiction may be identified and these microRNAs may be a potential target in the treatment of cocaine addiction.