Safe, Rapid Telomere Extension to Prevent and Treat Hypertension

描述（由申请人提供）：我们最近展示了一种新的、独特的端粒延长药物：核苷修饰的编码端粒酶的mRNA。我们的mRNA药物在6天内延长了端粒，其长度大约是正常人平均15年衰老过程中端粒缩短的量，而且我们的药物是短暂的，几天内就会被翻转。独特的是，这种方法有可能实现安全的端粒延长治疗，因为它可以如此迅速地延长端粒，以至于治疗可以很短（几天），在短暂的治疗结束后，正常的抗癌端粒缩短机制仍然完好无损。我们的药物不与基因组整合，不具有免疫原性，因为它含有与最近发现的成熟哺乳动物mRNA相同的修饰核苷，并且可以编码端粒酶的形式，避免翻译后调节，即使在缓慢循环的细胞群（如一些祖细胞）中也能使端粒延长。我们和我们的合作者正在将我们的药物应用于由短端粒介导的几种与年龄相关的疾病：高血压和心力衰竭（Cooke和Blau实验室），免疫衰老（Weyand实验室）和血管性痴呆（Yesavage实验室）（见支持信）。这些应用都将通过这个项目得到促进：在这里，我们建议通过优化静脉给药和证明其安全性和有效性，开始将我们的药物转化为人类研究。为了优化我们药物的静脉注射，我们将比较目前最好的和最先进的RNA载体。2007年发现，在人体内，外泌体通过包括血液在内的体液在细胞间转运mRNA， 2011年，自体外泌体通过静脉注射的方式传递核酸。我们将测试自体外泌体作为静脉给药的载体。我们将在短端粒mterc缺失的高血压小鼠模型中，使用我们最好的静脉给药方法延长血管内皮细胞端粒，以预防或治疗高血压。高血压是心力衰竭的主要危险因素，端粒短的小鼠同时表现出高血压和心力衰竭，而在人类中，端粒短可以预测这两种情况。在端粒短的小鼠和人类中，高血压的一个关键致病机制是衰老的内皮细胞产生过多的内皮素-1，我们（库克实验室）已经证明，端粒延长可以防止内皮细胞衰老。因此，有强有力的证据支持我们的药物延长内皮细胞端粒有助于预防或治疗高血压的假设。我们还将通过定量免疫反应、肿瘤形成和对短端粒高血压小鼠寿命的影响来测试我们药物的安全性。如果成功，这项工作将启动我们和我们的合作者将我们的快速、安全的端粒延长疗法用于预防和治疗高血压和其他与年龄相关的疾病的临床翻译（见支持信）。

DESCRIPTION (provided by applicant): We recently demonstrated a novel, uniquely-enabling drug for telomere extension: nucleoside-modified mRNA encoding telomerase. Our mRNA drug extends telomeres in six days by approximately the amount by which telomeres shorten over 15 years of normal human aging on average, and our drug is transient, being turned over within a few days. Uniquely, this approach has the potential to enable safe telomere extension therapy, because it extends telomeres so rapidly that the treatment can be very brief (a few days), leaving the normal anti-cancer telomere-shortening mechanism intact immediately after the brief treatment ends. Our drug does not integrate with the genome, is non-immunogenic as it comprises the same modified nucleosides recently discovered to comprise mature mammalian mRNA, and can encode forms of telomerase which avoid post- translational regulation enabling telomere extension even in slowly-cycling cell populations such as some progenitors. We and our collaborators are applying our drug to several age-related conditions mediated by short telomeres: hypertension and heart failure (Cooke and Blau labs), immunosenescence (Weyand lab), and vascular dementia (Yesavage lab) (see supporting letters). Each of these applications will be facilitated by this project: here we propose to initiate translation of our drug toward human studies by optimizing its intravenous delivery and demonstrating its safety and efficacy. To optimize i.v. delivery of our drug we will compare the best current and cutting-edge RNA vehicles. In 2007 it was discovered that in the human body, exosomes transport mRNA between cells via body fluids including blood, and in 2011 autologous exosomes were used to deliver nucleic acid via i.v. injection. We will test autologous exosomes as vehicles for i.v. delivery of our drug. We will use our best i.v. delivery method to extend telomeres of vascular endothelial cells to prevent or treat hypertension in the short-telomere mTERC-null mouse model of hypertension. Hypertension is the major risk factor in heart failure, and mice with short telomeres exhibit both hypertension and heart failure, and short telomeres predict both conditions in humans. In both mice with short telomeres and in humans, a key causative mechanism of hypertension is excess endothelin-1 production by senescent endothelial cells, and we (the Cooke lab) have shown that telomere extension prevents endothelial cell senescence. Thus there is strong evidence supporting the hypothesis that extension of endothelial cell telomeres by our drug will help prevent or treat hypertension. We will also test the safety of our drug by quantifying immune response, tumor formation, and effect on lifespan in the short-telomere hypertensive mice. If successful, this work will initiate translation of our rapid, safe telomere extension therapy toward the clinic for prevention and treatment of hypertension and other age-related conditions by us and our collaborators (see supporting letters).