汉恒生物-AAV8-大鼠大脑-2.pdfAAV作为基因治疗的传递体一直备受关注，而不同血清型的组织特

文件名称: 汉恒生物-AAV8-大鼠大脑-2.pdf

所属分类: 其它

开发工具:

文件大小: 2mb

下载次数: 0

上传时间: 2019-09-04

提供者: liumi*****

下载 (2mb)

不能下载？报告错误

详细说明：AAV作为基因治疗的传递体一直备受关注，而不同血清型的组织特异性也是大家关心的重点。ACCEPTED MANUSCRIPT actin depolymerization ac cuIn cytoskeleton spine shrinkage stress p-cofillinV miR-134个> P-Limk1 Synaptic plasticity (reduced synaptic strength) depression-like behaviors The hypothesis of molecular mechanisms underlying the modulatory effects of miR-134 on neuroplasticity and depression-like behaviors. ACCEPTED MANUSCRIPT MiR-134 modulates chronic stress-induced structural plasticity and depression-like behaviors via downregulation of limk1/cofilin signaling in rats liqin Fan, Xiuzhi zhu, Qiqi song, Peng Wang, Zhuxi Liu, Shu Yan Yu* 1. Department of Physiology, Shandong University, School of Medicine, Wenhuaxilu road, Jinan, Shandong Province, 250012, PR China 2. Shandong Provincial Key Laboratory of Mental Disorders, School of Medicine, Wenhuaxilu Road, Jinan, Shandong Province, 250012, PR China Corresponding author: Shu Yan Yu E-mail address: shuyanyu(asdu. edu.cn Tel:+86-0531-88383902:fax:+86-0531-88382502 ACCEPTED MANUSCRIPT Abstract Increasing evidence has suggested that depression is a neuropsychiatric condition associated with neuroplasticity within specific brain regions. However, the mechanisms by which neuroplasticity exerts its effects in depression remain largely uncharacterized. In the present study we show that chronic stress effectively induces depression-like behaviors in rats, an effect which was associated with structural changes in dendritic spines and synapse abnormalities within neurons of the ventromedial prefrontal cortex(vmPFC). Moreover, unpredictable chronic mild stress (UCMS) exposure significantly increased the expression of miR-134 within the vInPFC, an effect which was paralleled with a decrease in the levels of expression and phosphorylation of the synapse-associated proteins, LIM-domain kinase I(Limk1) and cofilin. An intracerebral infusion of the adenovirus associated virus (AAV)-miR-134-sponge into the vmPFC of stressed rats, which blocks mir-134 function, significantly ameliorated neuronal structural abnormalities, biochemical changes and depression-like behaviors. Chronic administration of ginsenoside rgl (40 mg/kg, 5 weeks), a potential neuroprotective agent extracted from ginseng, ignificantly ameliorated the behavioral and biochemical changes induced by UCMS exposure. These results suggest that mir-134-mediated dysregulation of structural plasticity may be related to the display of depression-like behaviors in stressed rats The neuroprotective effects of ginsenoside rgl, which produces an antidepressant like effect in this model of depression, appears to result from modulation of the miR-134 signaling pathway within the vmPFC ACCEPTED MANUSCRIPT Key words: Structural plasticity; miR-134: Ventromedial prefrontal cortex Depression; Ginsenoside Rgl Introduction Depression, which is associated with notable alterations in neural activities within specific brain circuits, is considered a major neuropsychiatric disorder in contemporary society (Vaidya and Duman 2001; Mayberg 2003). Recently, the ventromedial prefrontal cortex (vmPFC) has emerged as the important brain region in the pathogenesis of depression(Holmes and Wellman 2009; McLaughlin et al. 2009 Radley et al. 2006). Although the functional changes within the vmPFC as related to depression have yet to be fully elucidated, the reciprocal pathways that exist between the vmPFC and other critical structures associated with depression suggest some potential relationships. In specific, the connections involving the vmPFC with that of the hippocampus and amygdala, insinuate its involvement in deficits of executive functions such as memory, cognition and reward-related processes, as well as emotional dysregulation among other stress-related behaviors in rodents. In further support for a significant role of the vmPFC in depression are results obtained from neuroimaging studies which revealed that reductions of vmPfc activity were associated with depression (Takahashi et aL. 2004 ). Moreover, alterations in the structure and function of dendrites were also found within the vmPFC in response to chronic stress in animal models(Cook et al. 2004, Goldwater et al. 2009). These ACCEPTED MANUSCRIPT findings demonstrate that modulations in the plasticity of vmPFC neurons are associated with modifications in brain circuity related to depression. However, the molecular mechanisms underlying these neuronal plasticity processes within the vmPFC and how depression-inducing stressors leads to these changes have yet to be investigated In the mammalian nervous system, microRNAs have been suggested to regulate the translation of messenger RNAs, and thereby play critical roles in neuronal development, differentiation and plasticity(lacoangeli et al. 2010; Presutti et al. 2006) For example, miR-124, which was found to be preferentially expressed in neurons represents an important regulator for the temporal progression of adult neurogenesis Cheng et al. 2009), while mir-132 appears to be critical for the formation and plasticity of neuronal connections ( Pathania et al. 2012). It has been hypothesized that miRNAs can repress the translation of synaptically localized mRNAs until these neurons are exposed to the appropriate extracellular stimuli, which will then result in the formation, maturation and/or plasticity of the synapse(bredy et al. 2011; Higuchi et aL. 2016). MiR-134, a brain-specific microrna which is mainly localized to the synapto-dendritic compartment of ncurons, has been suggested to negatively regulate dendritic spine development and plasticity(Schratt et al. 2006). Findings from recent studies have also demonstrated that mir-134 negatively regulates hippocampal synaptic plasticity to result in cognitive deficits by inhibiting mRNAs of plasticity-associated proteins such as Lim-domain-containing protein kinasel (Limk1) (Liu ct al. 2017). Limkl is considered to function as a positive regulator of actin ACCEPTED MANUSCRIPT filament dynamics via its capacity to inhibit cofilin activity, the key actin depolymerizing factor located in postsynaptic sites. The phosphorylation of LimkI which subsequently phosphorylates and inhibits the activity of cofilin, prevents the cleavage of filamentous actin, thereby stabilizing the actin cytoskeleton and spine sizes(Bamburg 1999, Gunning et al. 2015; Sarmiere and Bamburg 2002). It has been reported that a limki deficiency leads to abnormalities in dendritic spine structure and synaptic transmission efficiency in Limkl knockout mice effects similar to that found with miR-134 overexpression(Meng et al. 2002). Moreover, studies in rats have demonstrated that stress produces a long-term inhibition of limkI mrNA translation, an effect which is critical for changes in synaptic plasticity. Interestingly, both of these alterations are ameliorated with antidepressant treatment(Nava et al. 2017). Thus, when subjected to stress, the mir-134-mediated reductions in Limk1 phosphorylation levels may be responsible for the de-phosphorylation of cofilin, thereby resulting in depolymerization of actin filaments in post-synaptic sites to induce morphological changes in dendritic spines. However, whether such mechanisms are involved in the dysregulation of neuronal structural plasticity within the vmPFC as induced by chronic stress to produce depression-like behaviors are unknown Recently, traditional herbal medicines have become novel pharmacological tools for use in the treatment of various neurological disorders. The benefits of these agents reside in their neuroprotective effects and high safety margins (Nemeroff 2007; Van der Watt et al. 2008 ) Ginsenoside rgl, the active principle ingredient of the herb ACCEPTED MANUSCRIPT Panax ginseng, is now being investigated as a valuable neuroprotective agent in the treatment of Alzheimer's disease and other neurodegenerative disorders( zhang et al 2012, Song et al. 2013). It has also been reported that ginsenoside rgl shows significant neuroprotective effects in a variety of cognitive and memory deficit animal models(Wang et al. 2014; Zhu et al. 2014). In addition, findings from recent studies have revealed that ginsenoside rgl could also function as an antidepressant through its ability to reverse the decreases in hippocampal bdnf protein levels in mice subjected to chronic stress (Jiang et aL. 2012). Studies within our laboratory have shown that chronic treatment of ginsenoside rgl significantly ameliorated depression-like behaviors in rats, possibly via activating the CREB-BDNF signaling pathway, a crucial regulator in protecting and sustaining the normal structure and function of neurons (Zhu et al. 2016; Liu et al. 2016). Recent evidence has implicated that ginsenoside Rgl promotes the neural differentiation of mouse ldipose-derived stem cells via upregulation of miRNA-124 expression (Dong et al 2017), as well as by promoting angiogenesis, possibly through the modulation of mirna-214 or mirNA-23a expression( Chan et al. 2009: Kwok et al. 2015) Therefore, these results suggest that the neuroprotective effects of ginsenoside rg might serve as the basis to explain its antidepressant effects. However, detailed characterization of the neuronal mechanisms underlying neuronal structural and functional plasticity in depression and thus the antidepressant-like effects of ginsenoside Rglis remains to be explored Therefore, in the present study, we first investigated whether treatment with ACCEPTED MANUSCRIPT ginsenoside rgl could prevent the neuronal structural changes and depression-like behaviors induced by UCMs exposure in rats. To explore some of the underlying mechanisms of the neuroprotective and antidepressant-like effects of ginsenoside rgl the regulatory roles of miR-134 upon the structural plasticity-related proteins, Limk 1 and cofilin, were examined within the vmPFC, a crucial brain region involved in the pathogenesis of depression in the UCMs animal model 2. Materials and methods 2. 1. Animals Male Wistar rats(160-180g) were obtained from the Shandong University Animal entre. all procedures were approved by the shandong university Animal Care and Use Committee and were performed in accordance with the National Institutes of Health Guide for the Care and Use of Laboratory Animals(National Research Council, 1996). Animals were housed under standard laboratory conditions and allowed to adapt to these conditions for 7-8 days prior to use in the experiments Behavioral tests were performed in the dark phase of the light/dark cycle. All efforts were made to minimize the pain and numbers of the animals used in the experiments 2.2. Drugs and treatment

(系统自动生成,下载前可以参看下载内容)