U19NS126038

Site-Directed RNA Editing of Nav1.7 as a Novel Analgesic

Chronic pain is a leading cause of disability, affecting about one-third of adults worldwide, with a prevalence greater than heart disease, cancer, and diabetes combined. Misuse and abuse of opiates have led to a nationwide addiction and overdose crisis. Thus, there is an urgent need for alternative, non-addictive analgesics.

Non-selective voltage-gated sodium channel (Nav) blockers are among existing non-addictive FDA-approved drugs which can sometimes provide symptomatic relief for patients. However, their utility is limited by CNS and cardiac side effects. Genetic and functional studies of human pain disorders and animal models of pain have validated Nav1.7, a voltage-gated sodium channel that is preferentially expressed in peripheral neurons, as an attractive target for therapy.

Isoform-selective Nav blockers, however, are difficult to generate and those that have been tested in clinical trials are rapidly cleared from the body, limiting their effectiveness. Alternative approaches are needed. We propose a novel, non-addictive approach to treat chronic pain by editing the messages that encode Nav1.7 in order to alter its ion selectivity.

By changing a single lysine codon in the ion selectivity filter to arginine, the Na selective channel will become both Na+ and K+ selective, effectively creating a counter-current shunt that will dampen excitability. Site-Directed RNA Editing (SDRE) refers to novel mechanisms to generate programmed edits within RNAs. It relies on the ADAR (Adenosine Deaminase that Acts on RNA) enzymes, which are endogenously expressed in human cells, including sensory neurons.

Directed by a guide RNA (gRNA), SDRE systems convert precisely selected adenosines to inosine, a translational mimic for guanosine, which can recode specific amino acids. For use as an analgesic, editing mRNA is preferable to DNA because it is transient, thus limiting potential off-target effects, including malignant transformations. In addition, ADARs are endogenous while enzymes for DNA manipulation (e.g., Cas proteins) are not, thus SDRE will not be as immunogenic.

Compared to small molecule channel blockers, SDRE can be more specific because it relies on Watson-Crick base-pairing of gRNAs for targeting, and its effects are likely longer lasting because they will remain as long as the edited channels are expressed.

We propose to use SDRE to edit Nav1.7 K1395R to render the channel permeable to both Na+ and K+. We will generate efficient and specific reagents through an in vitro selection assay, and then test their efficacy in cells, human sensory neurons induced from pluripotent stem cells, and cultured mouse and human DRG neurons. For in vivo testing, we will construct a transgenic mouse model that is specifically designed to test SDRE reagents targeting human Nav1.7 with the goal of ameliorating inflammatory, migraine, and neuropathic pain.

The Marine Biological Laboratory

TO SUPPORT BASIC AND CLINICAL NEUROSCIENCE, BIOMEDICAL, BEHAVIORAL AND SOCIAL SCIENCE, EPIDEMIOLOGIC, HEALTH SERVICES AND HEALTH DISPARITY RESEARCH. TO DEVELOP NEW KNOWLEDGE AND APPROACHES RELATED TO THE PREVENTION, DIAGNOSIS, TREATMENT, ETIOLOGY, AND CONSEQUENCES OF DRUG ABUSE AND ADDICTION, INCLUDING HIV/AIDS. TO SUPPORT RESEARCH TRAINING AND RESEARCH SCIENTIST DEVELOPMENT. TO SUPPORT DISSEMINATION OF RESEARCH FINDINGS. SMALL BUSINESS INNOVATION RESEARCH (SBIR) LEGISLATION IS INTENDED TO EXPAND AND IMPROVE THE SBIR PROGRAMS TO EMPHASIZE AND INCREASE PRIVATE SECTOR COMMERCIALIZATION OF TECHNOLOGY DEVELOPED THROUGH FEDERAL SBIR RESEARCH AND DEVELOPMENT, INCREASE SMALL BUSINESS PARTICIPATION IN FEDERAL RESEARCH AND DEVELOPMENT, AND FOSTER AND ENCOURAGE PARTICIPATION OF SOCIALLY AND ECONOMICALLY DISADVANTAGED SMALL BUSINESS CONCERNS AND WOMEN-OWNED SMALL BUSINESS CONCERNS IN THE SBIR PROGRAM. THE LEGISLATION INTENDS THAT THE SMALL BUSINESS TECHNOLOGY TRANSFER (STTR) PROGRAM STIMULATE AND FOSTER SCIENTIFIC AND TECHNOLOGICAL INNOVATION THROUGH COOPERATIVE RESEARCH AND DEVELOPMENT CARRIED OUT BETWEEN SMALL BUSINESS CONCERNS AND RESEARCH INSTITUTIONS, FOSTER TECHNOLOGY TRANSFER BETWEEN SMALL BUSINESS CONCERNS AND RESEARCH INSTITUTIONS, TO INCREASE PRIVATE SECTOR COMMERCIALIZATION OF INNOVATIONS DERIVED FROM FEDERAL RESEARCH AND DEVELOPMENT, AND FOSTER AND ENCOURAGE PARTICIPATION OF SOCIALLY AND ECONOMICALLY DISADVANTAGED SMALL BUSINESS CONCERNS AND WOMEN-OWNED SMALL BUSINESS CONCERNS IN TECHNOLOGICAL INNOVATION.

93.279 - Drug Abuse and Addiction Research Programs

National Institute of Neurological Disorders and Stroke (NNDS) [HHS - NIH]

Massachusetts United States

State-Wide

HEAL Initiative: Analgesic Development Initial Translational Efforts [Small Molecules and Biologics] (U19 Clinical Trial Not Allowed) (RFA-NS-21-015)

Amendment Since initial award the End Date has been extended from 08/31/24 to 08/31/27 and the total obligations have increased 65% from $6,789,851 to $11,194,636.