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

描述（由申请人提供）：拟进行的研究将通过对我实验室开发的原始“RNA-a激活”技术（RNA-a；专利申请中，PCT- US2011-065939）的技术创新，开发上调X-linked基因的方法。如果成功，这种下一代RNA-a方法将有可能治愈数十种难治性X连锁疾病，如Rett综合征、脆性X综合征和杜氏肌营养不良症。在制药行业，目前的治疗策略几乎完全集中在蛋白质和microRNA靶点上。然而，lncrna赋予了蛋白质和小rna不可能具有的时间和空间特异性，并且与疾病相关的突变更常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链非编码rna （lncRNA）。事实上，设计针对位点特异性顺式作用lncrna的药物将绕过表观遗传复合物通过小分子进行一般活动的多效效应模式。第一代RNA-a策略通过破坏Polycomb suppression complex 2 （PRC2）与靶向其感兴趣位点的lncRNA之间的结合，重新唤醒表观遗传沉默基因。RNA-a技术实现了与RNAi相反的功能，并在临床前测试中被证明对多种疾病基因有效。然而，X连锁疾病基因不适合RNA-a，可能是因为X染色体失活（XCI）导致许多额外的异染色质层。XCI是哺乳动物剂量补偿机制，雌性细胞中的一条X染色体沉默以平衡与雄性细胞的基因表达。我的实验室在过去的16年里专门研究XCI，最近发现了参与XCI沿失活X染色体（Xi）扩散的X连锁元件。根据这些发现，我们假设应该有可能选择性地重新唤醒特定的Xi位点，而无需重新激活大部分或全部Xi。事实上，重新激活整个Xi是不可取的，因为我们已经证明，全局x重新激活会导致癌症。因此，治疗x连锁疾病需要一种基因激活的位点特异性方法。随着新发现的XCI如何传播的知识，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，我的实验室处于一个独特的位置，可以进一步开发RNA-a技术，以位点特异性的方式解锁Xi基因的表达。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来实现这一目标。

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.