Intranasal Delivery of Telomerase Reverse Transcriptase mRNA for Therapy ofTraumatic Brain Injury

摘要 据估计，美国每年约有300万例创伤性脑损伤(TBI)病例。 脑外伤可导致严重的精神和运动功能障碍或死亡。没有有效的方法 改善中重度颅脑损伤后认知能力的治疗。许多新的药理学方法可以治疗 脑外伤治疗效果不够好。基因疗法可以提供一种无法满足的解决方案，可以预防几种 神经退行性疾病，包括脑外伤。信使核糖核酸疗法/疫苗的最新进展吸引了 由于他们有能力解决未得到满足的临床需求，因此受到了极大的关注。例如，迅速发展的 新冠肺炎基因疫苗帮助控制了世界范围内的疫情。有效的信使核糖核酸疗法需要 脂质纳米粒(LNP)载体可保护信使核糖核酸免于降解。端粒，重复的非编码DNA 序列在组织修复和衰老中起着关键作用。脑内端粒缩短是血液引起的 血流障碍和细胞死亡相关的炎症，并影响组织再生能力。亚基的催化亚基 端粒酶是一种在细胞分裂过程中负责维持端粒长度的酶，是一种端粒酶 逆转录酶(TERT)。TL功能障碍与神经炎性和神经退行性变有关 并建议将其作为TBI结果的标志。此外，TERT被证明在 神经元的存活和认知，保护免受氧化应激和阻止神经元的凋亡。而TERT 是神经系统疾病的潜在靶点，目前还没有研究评估RNA疗法在脑损伤中解决TL的作用 目前还没有报告。在这里，我们提出了一种用于脑外伤治疗的变革性治疗方法，其中包括鼻内治疗。 (In)TERT mRNA-LNP脑内递送。LNP在到达靶向TBI组织的过程中保护mRNA。最直接的 我们的工作重点是大脑的正常功能受到冲击对头部造成的损害。我们的数据 表明IN传递LNP绕过了血脑屏障，增强了药物向大脑的转运。我们的团队已经 研究表明，TERT mRNA在体内外均能增强TL，改善其他退行性疾病的预后 条件。我们还表明，在我们的脑损伤中，端粒缩短和TERT水平降低 老鼠模型。 我们的方法可能会从根本上改变脑外伤以及其他脑部疾病的治疗方法。在这 探索性项目，我们的中心假设是，在管理TERT mRNA将使暂时 端粒酶逆转录酶在脑外伤后认知功能恢复中的表达我们的具体目标是： (1)mRNA-LNP的设计、鉴定及体外生物相容性：四个TERT-mRNA-LNP系统将被 设计、表征和评估不同脑细胞的体外；(2)评估生物分布和 脑内注射TERT mRNA-LNPs对小鼠脑损伤模型的治疗作用 影响，CCI)。小鼠脑内报告基因和荧光标记LNP的生物分布 TBI将 被执行。有效性将基于TERT水平、TL、行为测试和免疫标记物进行测试。 这一探索性项目可能是开发急需的脑损伤治疗方法的第一步。

ABSTRACT It is estimated that annually ~3 million Traumatic brain injury (TBI) cases occur in the U.S. Moderate to severe TBI can cause significant impairments in mental and motor functions or death. There are no effective therapies to improve cognitive abilities after moderate-severe TBI. Many novel pharmacological approaches for TBI therapy are not effective enough. Gene therapy can provide an unmet solution in protecting against several neurodegenerative disorders, including TBI. Recent advances in mRNA therapeutics/ vaccines have drawn significant attention due to their ability to tackle unmet clinical needs. For instance, the prompt development of COVID-19 mRNA vaccines aided in controlling the pandemics worldwide. Efficient mRNA therapies require a Lipid Nanoparticles (LNP) carrier to protect mRNA from degradation. Telomeres, repetitive non-coding DNA sequences, have a pivotal role in tissue repair and aging. Telomere shortening in the brain results from blood flow impairment and cell-death related inflammation and affects tissue regeneration ability. A catalytic subunit of telomerase, an enzyme responsible for maintaining telomere length (TL) during cell division, is telomerase reverse transcriptase (TERT). TL dysfunction has been implicated in neuroinflammatory and neurodegenerative processes and proposed as a marker for TBI outcomes. Additionally, TERT was shown to be important in neuronal survival and cognition, protecting from oxidative stress and blocking neuronal apoptosis. While TERT is a potential target in neurological disorders, no studies evaluating RNA therapy to address TL in TBI were reported yet. Here we propose a transformational therapeutic approach for TBI therapy which includes intranasal (IN) TERT mRNA- LNP delivery to the brain. LNP protect mRNA en route to the target TBI tissue. The immediate focus of our work is an impairment in the brain's normal function caused by an impact to the head. Our data show that IN delivery of LNP bypasses BBB, enhancing drug transport to the brain. Our teams have demonstrated that TERT mRNA can enhance TL in vitro and in vivo improving prognosis in other degenerative conditions. We have also shown that there is a shortening of telomeres and reduction in TERT levels in our TBI mouse model. Our approach may radically change therapy for TBI, as well as other brain disorders. In this exploratory project, our central hypothesis is that IN administration of TERT mRNA will enable temporary expression of TERT in the affected brain tissue restoring cognitive functions after TBI. Our Specific aims are: (1) Design, characterization, and biocompatibility of mRNA-LNP in vitro: four TERT-mRNA-LNP systems will be designed, characterized, and assessed in vitro with various brain cells; (2) Evaluate the biodistribution and therapeutic efficiency of IN administration of TERT mRNA-LNPs in a mouse model of TBI (Controlled cortical impact, CCI). Biodistribution of reporter mRNA and fluorescently labeled LNP in the brains of mice with TBI will be performed. Efficiency will be tested based on TERT levels, TL, behavioral tests, and immunological markers. This exploratory project can be the first step in the development of a much-needed therapy for TBI.