Funded Projects

Voltage-gated sodium channels such as Nav1.7, Nav1.8, and Nav1.9 transmit pain signals in nerve fibers and are molecular targets for pain therapy. While Nav channels have been validated as pharmacological targets for the treatment of pain, available therapies are limited due to incomplete efficacy and significant side effects. Taking advantage of recent advances in structural biology and computational-based protein design, this project aims to develop antibodies to attach to Nav channels and freeze them in an inactive state. These antibodies can then be further developed as novel treatments for chronic pain.

Identification of new targets and mechanisms underlying chronic neuropathic pain is essential for the discovery of novel treatments and preventative tactics for better neuropathic pain management. A recent exploration of next-generation RNA sequencing identified a large, native, full-length long noncoding RNA (lncRNA) in mouse and human dorsal root ganglion (DRG). It was named as nerve injury-specific lncRNA (NIS-lncRNA), since its expression was found increased in injured DRGs, in response to peripheral nerve injury, but not in response to inflammation. Preliminary findings revealed that blocking the nerve injury-induced increases in DRG NIS-lncRNA levels ameliorated neuropathic pain. This project will validate NIS-lncRNA as a therapeutic target in animal models of neuropathic pain and in cell-based functional assays utilizing human DRG neurons. Completion of this proposal will advance neuropathic pain management and might provide a novel, non-opioid pain therapeutic target.

 Chronic persistent post-operative pain (CPOP) is a devastating outcome from any type of surgical procedure. Its incidence is anywhere between 20-85% depending on the type of surgery, with thoracotomies showing one of the highest annual incidences of 30-60%. Given that millions of patients (approximately 23 million yearly based on incidence) are affected by CPOP, the results are increased direct medical costs, increased indirect medical costs due to decreased productivity, and associated negative effects on an individual’s physical functioning, psychological state, and quality of life. Given these extensive public health and economic consequences there is a resurgence of research in the area of preventative analgesia.  The goal of this project is to evaluate a novel small molecule antagonist of MD2-TLR4, DT-001 in preclinical models of surgical pain representative of persistent post-operative pain. In collaboration with University of California, San Diego, DT-001 will be evaluated for its ability to block the development of neuropathic pain states. These studies will evaluate dose escalating efficacy of DT001 in rats in formalin and spinal nerve injury (SNI) models using both intrathecal and intravenous routes of administration. Tissues will be preserved to assess functional effects on relevant pain centers for analysis by Raft. With demonstration of efficacy, these studies will determine the optimal dose and route of administration of DT001 and guide a development path to IND and eventually clinical trials.

Neck pain is the fourth leading cause of disability and also a significant cause of cervicogenic headaches. Many of the currently available neck pain treatments are invasive with associated risks and complications, particularly because of the complex anatomy. Magnetic resonance guided focused ultrasound, a novel, completely noninvasive technique, can precisely target spinal facet joints to help ameliorate neck pain, potentially transforming the current practices. The goal of this study is to develop a cervical spine-specific device and demonstrate its safety and efficacy on targeting cervical sensory fibers and the third occipital nerve. The results of these studies will provide an understanding on how to best use this technology for chronic neck pain as well as a basis for translation into human use.

Neuropathic pain is characterized by neuronal hyperexcitability and spontaneous activity, properties associated with activity of hyperpolarization-activated, cyclic nucleotide-regulated (HCN1-4) channels, the source of the pacemaker current, Ih. Inhibition of HCN1-mediated Ih elicits marked antihyperalgesia in multiple animal models of neuropathic pain, including models for direct nerve injury and chemotherapy-induced peripheral neuropathy, and does so with little or no disruption to either normal pain processing or baseline behaviors and activities. The overall objective is to develop a peripherally restricted HCN1 inverse-agonist as a therapeutic for neuropathic pain. Researchers have generated a novel small molecule that combines an antihyperalgesic HCN1 inhibitor with a motif that controls distribution and membrane presentation and is a potential non-opioid antihyperalgesic treatment for peripheral neuropathic pain.

Chronic pain from tissue injury often stems from long-term changes in spinal cord circuits that change nerve sensation. Reversing these changes may provide better pain therapeutics. Previous work in animal models showed that activating G protein-coupled receptor 37 (GPR37) dampens nerve signal intensity after long-term stimulation and alleviates pain behavioral responses. This project aims to validate GPR37 in the spinal cord as a useful target for new treatments for neuropathic pain. The work will facilitate screening and identification of new molecules that activate GPR37, which can then be tested for efficacy and safety in further research in animal models of pain.

Pain signals originate predominantly in a subset of peripheral sensory neurons that harbor a distinct subset of voltage-gated sodium (NaV) channels; however, current NaV channel blockers, such as local anesthetics, are non-selective and also block NaV channels vital for function of the heart, muscle, and central nervous system. Genetic studies have identified human NaV1.7, NaV1.8, and NaV1.9 channel subtypes as key players in pain signaling and as major contributors to action potential generation in peripheral neurons. ProTx-II is a highly potent and moderately selective peptide toxin that inhibits human NaV1.7 activation. This study will optimize ProTx-II selectivity, potency, and stability by exploiting the new structures of ProTx-II—human NaV1.7 channel complexes, advances in rational peptide optimization, and rigorous potency and efficacy screens to generate high-affinity, selective inhibitors of human NaV1.7, NaV1.8, and NaV1.9 channels that can define a new class of biologics to treat pain.

Multidisciplinary chronic pain treatments show incomplete recovery at the population level because of significant heterogeneity on the individual level in the high impact chronic pain population. Subgroups of individuals either completely respond, do not change, or even worsen following pain management. Therefore, diagnostic biomarker signatures are needed to differentiate high impact chronic pain from low impact chronic pain. This study aims to develop prognostic biomarkers to predict the disease trajectory for individuals with musculoskeletal high-impact chronic pain. These biomarker signatures will integrate central nervous system (CNS), multi-?omic?, sensory, functional, psychosocial, and demographic domains into detection algorithms. Biomarker signatures from the proposed research are intended to facilitate risk and treatment stratification for clinical trial design and to facilitate treatment decisions in clinical practice for patients with musculoskeletal chronic pain.

MNK-eIF4E signaling is activated in nociceptors upon exposure to pain or peripheral nerve injury, promoting cytokines and growth factors and increasing nociceptor excitability, which leads to neuropathic pain. Genetic or pharmacological inhibition of MNK signaling blocks and reverses nociceptor hyperexcitability as well as behavioral signs of neuropathic pain. A clinical phase drug for cancer shows strong specificity as an MNK inhibitor but requires optimization because MNK inhibition in the central nervous system (CNS) may lead to depression, an unacceptable side effect for a neuropathic pain drug. The research team plans a targeted medicinal chemistry and screening campaign directed at generating a MNK-inhibitor-based neuropathic pain treatment with the goal of restricting its CNS penetration while retaining potency, specificity, and in vivo bioavailability and efficacy.

Most of the 200k Americans who undergo thoracotomy each year receive opiates to reduce postoperative pain because clinicians have few non-addictive, cost-effective choices to control the severe pain patients often experience in the first two weeks after surgery. Managing pain post-thoracotomy is critical to enable patients to take deep breaths and remove (via coughing) lung secretions that otherwise significantly increase risk of pneumonia and collapsed lung, hospital re-admission and morbidity. The most severe pain associated with thoracotomy is transmitted along the intercostal nerves, but no long-term analgesic or nerve block device exists that can provide safe and effective long-term reduction of pain. A reversible, patient-controlled, non- addictive, intercostal nerve block device would reduce suffering due to thoracotomy, broken ribs and herpes zoster. In this Phase I project, the team will develop a minimally invasive thermal nerve block device that can control nerve conduction by gently warming and cooling a short nerve segment between room temperature and warm water temperature. This novel approach is based on the discovery that warm and cool temperature mechanisms of nerve block are different and additive, enabling moderate-temperature nerve block by cycling neural tissues slightly above and below body temperature. Reversible thermal nerve blocks represent a completely new approach to managing pain.  

Taxanes are among the most effective chemotherapeutic agents and are frequently used in the treatment of early stage and metastatic breast cancer. However, they are known to produce a pain condition known as Chemotherapy-Induced Peripheral Neuropathic Pain (CIPNP). CIPNP is one of the primary reasons a patient receives a limited dose of taxane. No diagnostic tool exists to identify patients that will develop CIPNP in response to taxane therapy. Biomarker signatures associated with taxane-induced neuropathic pain will be developed to: 1) identify patients at risk for developing debilitating taxane neuropathic pain before chemotherapy is initiated; and 2) to identify patients already on treatment who are at risk of developing neuropathic pain and need dosing adjustments to prevent CIPNP symptoms. This biomarker signature will be used to detect CIPNP-susceptible patients early and personalize their taxane therapy to minimize CIPNP while optimizing the therapeutic taxane dosing.

The use of a pain imaging technology would allow for objective efficacy data (both pre-clinically and in clinical trials), and reduce costs by enabling smaller sample sizes due to more homogeneous populations; i.e. with a particular “pain signal,” and more accurate measurement of analgesic effects. This research team recently invented a novel positron emission tomography (PET) imaging agent as a tool to address these issues in pain care and therapy development. Although the ability of PET to detect pathological changes for (early) disease detection is widely used in cancer and neurological diseases, it has not yet been used for pain indications. The goals of this project are: 1) to change the evaluation of (experimental) pain therapies, and 2) the standard of care in pain assessment through molecular imaging. The proposed study is designed to determine the feasibility of our imaging agent to objectively measure pain in rodents. This will set the stage for a Phase II study that further develops this agent into a tool for quantifying pain/analgesia.