The RNA-activation platform to treat X-linked disease in a locus-specific manner.

描述(由申请人提供)：拟议的研究将开发通过应用于我的实验室开发的原始“核糖核酸激活”技术的技术创新来上调X连锁基因的方法(rna-a；正在申请专利，PCT-US2011-065939)。如果成功，这种下一代RNA-a方法学将有可能治愈数十种难治的X连锁疾病，如Rett综合征、脆性X综合征和Duchenne肌营养不良症。在制药行业，目前的治疗策略几乎完全集中在蛋白质和microRNA靶标上。然而，lncRNA具有蛋白质和小RNA所不具备的时间和空间特异性，而且与疾病相关的突变更多地发生在非编码空间，而不是编码空间。治疗策略可能同样有效地针对长非编码RNA(LncRNA)。事实上，设计针对特定部位顺式作用的lncRNA的药物将绕过通过小分子影响表观遗传复合体一般活性的多效性效应。第一代RNA-一种策略，通过破坏多聚梳抑制复合体2(PRC2)与以其为靶点的lncRNA之间的结合，重新唤醒表观遗传沉默的基因。RNA-a技术实现了与RNAi相反的效果，并已被证明在临床前测试中对各种疾病基因有效。然而，X连锁疾病基因并不适用于RNA-a，这可能是因为X染色体失活(XCI)导致了许多额外的异染色质层。XCI是哺乳动物的剂量补偿机制，在这种机制下，雌性细胞中的一条X染色体被沉默，以平衡雄性细胞的基因表达。我的实验室在过去的16年里一直致力于XCI的研究，最近发现了与XCI沿着不活跃的X染色体(Xi)传播有关的X连锁元件。根据这些发现，我们假设有可能有选择地重新唤醒特定的XI基因座，而不需要重新激活大部分或全部XI。事实上，重新激活整个XI将是不可取的，因为我们已经证明，全球X-重新激活会导致癌症。因此，治疗X连锁疾病需要一种特定的基因激活方法。有了XCI如何传播的新知识，设想的下一代RNA-a技术有可能做到这一点。由于我们在XCI和RNA-a方面的专业知识，我的实验室处于独特的地位，可以进一步开发RNA-一种以特定于基因座的方式解锁xi基因表达的技术。在这里，我们建议通过利用XI上的基因特异性控制元件来重新激活模型疾病基因MECP2来实现这一点。

DESCRIPTION (provided by applicant): The proposed research will develop methods of upregulating X-linked genes through technical innovations applied to the original "RNA-activation" technology developed in my laboratory (RNA-a; patent pending, PCT- US2011-065939). If successful, this next-generation RNA-a methodology will have the potential to cure dozens of intractable X-linked diseases such as Rett syndrome, Fragile X syndrome, and Duchenne muscular dystrophy. In the pharmaceutical industry, current therapeutic strategies focus almost exclusively on protein and microRNA targets. Yet, lncRNAs confer a temporal and spatial specificity not possible with proteins and small RNAs, and disease-associated mutations occur more often in noncoding than coding space. Therapeutic strategies might be as effectively targeted at long noncoding RNAs (lncRNA). Indeed, designing drugs against site-specific cis-acting lncRNAs would circumvent the pleiotropic effects plaguing modalities that general activities of epigenetic complexes via small molecules. The first-generation RNA-a strategy reawakens epigenetically silenced genes by disrupting binding between Polycomb repressive complex 2 (PRC2) and the lncRNA that targets it to the locus of interest. The RNA-a technology achieves the opposite of RNAi and has proven efficacious for various disease genes in preclinical testing. However, X-linked disease genes have not been amenable to RNA-a, likely because of many additional layers of heterochromatin resulting from X- chromosome inactivation (XCI). XCI is the mechanism of dosage compensation in mammals in which one X- chromosome is silenced in female cells to balance gene expression with male cells. My laboratory has specialized in the study of XCI for the past 16 years and recently discovered X-linked elements involved in the spreading of XCI along the inactive X chromosome (Xi). From these discoveries, we hypothesize that it should be possible to selectively reawaken specific Xi loci, without reactivating most or all of the Xi. Indeed, reactivating the entire Xi would be undesirable, as we have shown that global X-reactivation results in cancer. Thus, treating X-linked diseases requires a locus-specific approach to gene activation. With newfound knowledge of how XCI spreads, the envisioned next-generation RNA-a technology has the potential to do this. Because of our expertise in XCI and RNA-a, my lab is in a unique position to further develop the RNA-a technology to unlock expression of Xi genes in a locus-specific manner. Herein we propose to achieve this by leveraging gene-specific control elements along the Xi to reactivate the model disease gene, MECP2.