2020 Mitchell Max Awardee:
Dr. Ana Moreno
CEO, Navega Therapeutics
Ana Moreno, PhD, Navega Therapeutics, San Diego, CA
Ana Moreno received a bachelor’s in Biosystems Engineering from the University of Arizona with a focus on biosensors; and a master’s and doctorate in Bioengineering from the University of California San Diego, with a research focus on developing CRISPR-Cas9 platforms to broaden their applications to also include genome regulation. Her work included the first published work to demonstrate the in vivo use of a nuclease-null Cas9 (dCas9) that resulted in a phenotypic improvement, specifically in a mouse model of retinitis pigmentosa. In addition, Moreno also demonstrated the utility of dCas9 in prevention and amelioration of chronic pain. For her graduate work, Moreno received CONACYT and UCMEXUS fellowships and the Engelson PhD Thesis Award. In 2018, Moreno founded Navega Therapeutics, a startup tackling the opioid epidemic via gene therapies for chronic pain, where she is the CEO.
ABSTRACT:
Repression of Sodium Channels via a Gene Therapy for Treatment of Chronic Neuropathic Pain
Ana M. Moreno, Fernando Aleman, Tony Yaksh, Prashant Mali
Navega Therapeutics, Inc.
Significance: Chronic pain affects between 19-50% of the world population, with over 100 million people in the US alone. Current treatments consist mainly of opioids, which present severe side effects and risk of addiction. This burgeoning health crisis demands urgent development of alternative non-addictive methods to manage pain. A therapeutic alternative to opioids that is effective and long lasting would therefore alter the current paradigm.
Background: The human genome encodes genes that can confer protection to unnecessary pain. There are nine voltage gated sodium channel subtypes, of which NaV1.7, NaV1.8, NaV1.9 have been implicated in nociceptive transmission and/or contribution to the hyperexcitability in primary afferent nociceptive and sympathetic neurons. Previous studies have demonstrated that reduction of NaV1.7, NaV1.8, and NaV1.9 activity leads to reduced inflammatory or neuropathic pain. In addition, characterization of mutations in these channels have confirmed a causative link of these channels to human pain disorders. Since the discovery of the relationship between humans with NaV1.7 (SCN9A) mutations and congenital insensitivity to pain, this sodium channel has been an attractive target for developing chronic pain therapies. However, efforts to develop selective small molecule inhibitors have been hampered due to the high sequence identity between NaV subtypes, and in fact, many small-molecule drugs targeting NaV1.7 have failed due to side-effects caused by lack of specificity. Antibodies have faced a similar situation since there is a tradeoff between selectivity and potency due to the binding to a specific (open or close) conformation of the channel. Thus, no drug targeting this gene has reached the final phase of clinical trials. In our proof of concept in mice, we have successfully repressed NaV1.7 in the Dorsal Root Ganglia (DRGs). We delivered a variant of CRISPR-Cas9 system without nuclease activity (dCas9) and a guide-RNA (gRNA) targeting NaV1.7 into mice via AAV9 to enable pain relief for weeks. This project utilizes a novel way of targeting NaV genes via epigenome repression instead of genome edition, for non-addictive and long-term pain relief without permanent changes in the genome, lowering potential side effects.
Objective: We have developed a non-permanent gene therapy via CRISPR-dCas9 to target pain that is nonaddictive, highly specific, and long-lasting. During this Phase I SBIR, we will 1) test additional pain targets in vitro, and 2) evaluate the new targets in vivo in mice models of inflammatory and neuropathic pain. In addition, we will initiate our toxicology studies in mice. At the end of this Phase I work, we will know the efficacy and safety of our candidates to perform IND-enabling toxicology studies in Phase II.
Specific Aims:
Aim 1: In vitro optimization of gRNA designs. Apart from the NaV1.7 channel, other sodium channels have been involved in pain signaling, mainly NaV1.8 and NaV1.9. By taking advantage of single and dual gene targeting via multiple gRNAs, we will be testing single and dual inhibition of NaV channels to determine which one shows higher efficacy. We hypothesize that targeting two NaV channels will increase pain relief, and thus, will
require lower dosage.
Aim 2: In vivo evaluation of new targets. The best constructs from Aim 1 will be tested in adult male and female mice and compared to a negative control (non-targeting gRNA) and a positive control (Gabapentin) in a neuropathic (mononeuropathy) nerve ligation pain model (Chung’s model) and a Carrageenan induced inflammatory pain model.
Conclusions: These studies will help determine whether single NaV knockdown (1.7, 1.8, 1.9), or a combination of these is more effective to ameliorate pain in an inflammatory and/or neuropathic pain rodent models and assess sex differences. Unlike small-molecules or antibodies which would be very difficult to design for multiple-gene targeting, our precision medicine approach takes the advantage of being able to specifically target single or multiple genes.