GENOME-EDITING APPLICATIONS OF CRISPR-CAS9 TO treatment of depression; A PILOT animal model STUDY

Background and Aim : Major depressive disorder (MDD) is characterized by depressed mood, diminished interests, impaired cognitive function and vegetative symptoms. The lifetime prevalence of MDD is 20.6% and its heritability is estimated to be approximately 35% which along with environmental factors, are associated with the risk of developing MDD. Recently, the clustered regularly interspaced short palindromic repeats-CRISPR-associated protein 9 (CRISPR-Cas9) systems was developed, which improves sequence-specific gene editing in cell lines, organs, and animals. CRISPR system would selectively disrupt the targeted location without affecting other region of DNA. Several long non-coding RNAs (lncRNAs) were found associated with etiology of major depressive disorder.Methods : We set out to design and use a CRISPR system to disrupt expression of LncRNA named AK036791 in a mouse model of depression. Two group of male mouse were used (wild-type C57BL/6 mice, 7–8 weeks old, male, 20-25 g). The mouse model of depression produced by isolation model examined with forced swimming test. Test group were CRISPR/Cas9 knock-in mice model to induce doxycycline-regulated Cas9 induction that enables widespread gene disruption in multiple tissues and that limiting the duration of Cas9 expression. Then forced swimming test were conducted and expression level of AK036791 was assessed in nucleus accumbens of both groups by using quantitative time PCR.Results : Results showed 3 time decrease in expression level of AK036791 in nucleus accumbens of test group (p<003). Forced swimming test showed improvement of depression in test group in swimming(p<03) and climbing time(p<003).Conclusion : It seems that designed CRISPR/Cas9 could induce reduction of expression of genes that are involved in depression. CRISPR/Cas9 also can use for developing knock-in and knock-out mice that may help to shed light to molecular mechanisms of depression in central nervous system.