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

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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.