Yang Yang, Hu Zhiying, Du Xiaoxue, Davies Henry, Huo Xue, Fang Marong
Institute of Neuroscience, Zhejiang University School of MedicineHangzhou, China.
Department of Obstetrics and Gynecology, Hangzhou Red Cross HospitalHangzhou, China.
Front Neurosci. 2017 Jul 25;11:428. doi: 10.3389/fnins.2017.00428. eCollection 2017.
In the clinic selective serotonin reuptake inhibitors (SSRIs), like Fluoxetine, remain the primary treatment for major depression. It has been suggested that miR-16 regulates serotonin transporters (SERT) via raphe nuclei and hippocampal responses to antidepressants. However, the underlying mechanism and regulatory pathways are still obtuse. Here, a chronic unpredicted mild stress (CUMS) depression model in rats was established, and then raphe nuclei miR-16 and intragastric Fluoxetine injections were administered for a duration of 3 weeks. An open field test and sucrose preference quantification displayed a significant decrease in the CUMS groups when compare to the control groups, however these changes were attenuated by both miR-16 and Fluoxetine treatments. A dual-luciferase reporter assay system verified that hsa-miR-16 inhibitory effects involve the targeting of 3'UTR on the 5-HTT gene. Expression levels of miR-16 and BDNF in the hippocampus were examined with RT-PCR, and it was found that increased 5-HT2a receptor expression induced by CUMS can be decreased by miR-16 and Fluoxetine administration. Immunofluorescence showed that expression levels of neuron NeuN and MAP-2 in CUMS rats were lower. Apoptosis and autophagy levels were evaluated separately through relative expression of Bcl-2, Caspase-3, Beclin-1, and LC3II. Furthermore, CUMS was found to decrease levels of hippocampal mTOR, PI3K, and AKT. These findings indicate that apoptosis and autophagy related pathways could be involved in the effectiveness of antidepressants, in which miR-16 participates in the regulation of, and is likely to help integrate rapid therapeutic strategies to alleviate depression clinically. These findings indicate that miR-16 participates in the regulation of apoptosis and autophagy and could account for some part of the therapeutic effect of SSRIs. This discovery has the potential to further the understanding of SSRIs and accelerate the development of new treatments for depression.
在临床上，选择性5-羟色胺再摄取抑制剂（SSRI），如氟西汀，仍然是重度抑郁症的主要治疗药物。有研究表明，miR-16通过中缝核和海马对抗抑郁药的反应来调节5-羟色胺转运体（SERT）。然而，其潜在机制和调控途径仍不清楚。在此，建立了大鼠慢性不可预测轻度应激（CUMS）抑郁模型，然后对中缝核注射miR-16并灌胃给予氟西汀，持续3周。旷场试验和蔗糖偏好定量显示，与对照组相比，CUMS组显著降低，然而，miR-16和氟西汀治疗均减弱了这些变化。双荧光素酶报告基因检测系统证实，hsa-miR-16的抑制作用涉及靶向5-HTT基因的3'UTR。用RT-PCR检测海马中miR-16和脑源性神经营养因子（BDNF）的表达水平，发现CUMS诱导的5-HT2a受体表达增加可通过给予miR-16和氟西汀而降低。免疫荧光显示，CUMS大鼠中神经元NeuN和微管相关蛋白2（MAP-2）的表达水平较低。通过Bcl-2、半胱天冬酶-3（Caspase-3）、Beclin-1和微管相关蛋白轻链3-II（LC3II）的相对表达分别评估凋亡和自噬水平。此外，发现CUMS会降低海马中雷帕霉素靶蛋白（mTOR）、磷脂酰肌醇-3激酶（PI3K）和蛋白激酶B（AKT）的水平。这些发现表明，凋亡和自噬相关途径可能参与抗抑郁药的疗效，其中miR-16参与其调节，并且可能有助于整合快速治疗策略以在临床上缓解抑郁症。这些发现表明，miR-16参与凋亡和自噬的调节，并且可能是SSRI治疗效果的一部分原因。这一发现有可能进一步加深对SSRI的理解，并加速抑郁症新治疗方法的开发。
