Funded Projects

Neuropathic pain is a debilitating and complex medical condition for which safe and non-addictive treatment options are urgently needed. Preliminary studies have found that lysophosphatidic acid receptor 5 (LPA5) is present in areas of the body that signal pain, including at high levels in rodent models of neuropathic pain. This project will use genetic and pharmacological approaches to determine whether blocking LPA5 signaling reduces neuropathic pain toward future testing in humans.  

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.

Despite the need for non-opioid treatments for chronic pain, few alternative treatment approaches exist. Transcutaneous auricular neurostimulation (tAN) is a safe and effective treatment for pain during opioid withdrawal; however, researchers do not understand how tAN reduces pain, which limits its clinical use. A better understanding of how tAN affects neurophysiological processes to provide pain relief would likely expand tAN development and use. This interdisciplinary project will conduct research in both healthy adults and those with chronic pain to explain the neurochemical and neurophysiological mechanisms for tAN-based pain relief, and also help optimize treatments and their use.

Cholecystokinin B receptor (CCKBR) is a molecule found in the brain that helps regulate anxiety and depression but also influences the development of tolerance to opioids. CCKBR levels are also increased in models of nerve injury-induced (neuropathic) pain. Therefore, targeting CCKBR may offer a new approach to treating neuropathic pain and the associated anxiety and depression. Researchers have developed mouse antibodies that can inactivate CCKBR. However, to be usable in humans without causing an immune response, these antibodies need to be modified to include more human sequences. This project will use a fragment of the CCKBR antibody, modify it with the addition of human antibody sequences, and then select the clones that bind most strongly and specifically to human CCKBR. These will then be tested in cell and animal models of neuropathic pain to identify the most promising candidates for further evaluation in humans.

This project focuses on identifying and validating a new central analgesic circuit in the brain, based on a highly innovative hypothesis that the strong analgesic effects of general anesthesia (GA) are in part carried out by GA-mediated activation of the endogenous analgesic circuits. Preliminary discovery studies found that a subset of GABAergic neurons located in the central amygdala (CeA) become strongly activated and express high levels of the immediate early gene Fos under GA (hereafter referred to as CeAGA neurons). Furthermore, activation of these neurons exert profound pain-suppressing effects in an acute pain model and a chronic orofacial neuropathic pain model in mice. Based on these exciting preliminary findings, this project will identify and validate CeAGA neurons’ analgesic functions utilizing multiple mouse pain models. Identification of these shared common pathways that need to be suppressed by specific subtypes of CeAGA analgesic neurons will be highly critical for developing precise CeAGA-targeted therapies to treat chronic pain.

The primary goal of the PRECISION Human Pain network and its participating centers is to generate comprehensive datasets of molecular signatures and cellular function phenotypes or signatures of various cell types that underlie transmission and processing of pain signals in humans. To maximize the impact of the data generated through this effort, it is vital to standardize and integrate all data generated by the various centers and make these data available in a meaningful way to the larger scientific community. As the Data Coordination and Integration Center, this project will support the network to curate, harmonize, and effectively integrate center-generated datasets as well as provide operational support for the network and conduct educational and outreach efforts.

Although opioid-based analgesics have been proven effective in reducing the intensity of pain for many neuropathic pain conditions, their clinical utility is grossly limited due to the substantial risks involved in such therapy, including nausea, constipation, physical dependence, tolerance, and respiratory depression. Cumulative evidence suggests that human Mas-related G protein-coupled receptor X1 (MRGPRX1) is a promising target for pain with limited side effects due to its restricted expression in nociceptors within the peripheral nervous system; however, direct activation of MRGPRX1 at peripheral terminals is expected to induce itch side effects, limiting the therapeutic utility of orthosteric MRGPRX1 agonists. This finding led to the exploration of positive allosteric modulators (PAMs) of MRGPRX1 to potentiate the effects of the endogenous agonists at the central terminals of sensory neurons without activating peripheral MRGPRX1. An intrathecal injection of a prototype MRGPRX1 PAM, ML382, effectively attenuated evoked, persistent, and spontaneous pain without causing itch side effects. The goal of this study is to develop a CNS-penetrant small-molecule MRGPRX1 PAM that can be given orally to treat neuropathic pain conditions.

Natural products, which are substances found in nature and made by living organisms, have been used in the past as good sources for developing new medications. Natural products isolated from marine bacteria that attach to the pain-signaling protein sigma-2 receptor (also known as transmembrane protein 97 [TMEM97]), may serve as a starting point to create new, non-opioid pain medications. This project will use chemistry and biology approaches to refine such natural products as a treatment for neuropathic 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.

Infants exposed to opioids during pregnancy can develop neonatal opioid withdrawal syndrome (NOWS). To date, clinicians generally use subjective evaluation to determine if an infant has NOWS, how severe the condition is, and if the infant needs treatment with or without medications. This project will evaluate whether an objective physiologic measure—continuous measurement of oxygen levels in the infant’s blood—can be used to develop a scoring system for assessing NOWS severity. The project will also develop and test a device to continuously monitor blood oxygen levels in the infants.

Chronic pain results in long-term changes throughout the central nervous system. These include abnormal structure and function of the frontal cortex region of the brain, which relays pain messages and also the common pain-related conditions depression, anxiety, and cognitive impairment. Peripheral nerve injury results in widespread and long-lasting changes to DNA in the frontal cortex. DNA methylation, in which chemical tags are attached to DNA, is one way the body controls the activity of genes over time. This control occurs via proteins that recognize tagged DNA, and some of these proteins do not work properly in the frontal cortex many months after nerve injury. These changes occur after nerve injury and are linked to mechanical sensitivity. This project will determine this DNA-binding protein is a good target for finding new medications for chronic pain. 

Up to 5 percent of adolescents suffer from high-impact chronic musculoskeletal (MSK) pain, and only about 50 percent with chronic MSK pain who present for treatment recover. Current treatments for chronic MSK pain are suboptimal and have been tied to the opioid crisis. Discovery of robust markers of the recovery versus persistence of pain and disability is essential to develop more resourceful and patient-specific treatment strategies, requiring measurements across multiple dimensions in the same patient cohort in combination with a suitable computational analysis pipeline. Preliminary data has implicated novel candidates for neuroimaging, immune, quantitative sensory, and psychological markers for discovery. In addition, a standardized specimen collection, processing, storage, and distribution system is in place, along with expertise in machine learning approaches to extract reliable and prognostic bio-signatures from a large and complex data set. This project will facilitate risk stratification and a resourceful selection of patients who are likely to respond to current multidisciplinary pain treatment approaches.

The development of non-addictive pain therapeutics can help counter opioid addiction and benefit patients, including those who suffer from neuropathic pain, in particular diabetic neuropathic pain (DNP). This project’s goal is to develop a safe, efficacious, and non-addictive small-molecule drug that activates Kv7 voltage-gated potassium channels to address overactive neuronal activity in DNP. Researchers will discover Kv7 activators that favor Kv7 isoforms altered in DNP and found in dorsal root ganglia, decrease off-target side effects observed with the use of earlier non-biased Kv7 activators, and optimize the absorption, distribution, metabolism, excretion, and toxicity profiles of these activators. This screening paradigm is intended to establish a clinic-ready, well-tolerated, and widely effective product to treat neuropathic pain.