Funded Projects

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.  

Chronic focal neuropathic pain, which includes pain etiologies such as radiculopathy and radiculitis, focal peripheral neuropathies, and low back pain, affects as many as 25 million patients annually in the United States. Chronic focal neuropathic pain is maintained by genome-wide transcription regulation in the dorsal root ganglia (DRG) / spinal cord network. The transcription factors driving this regulation constitute a promising class of targets with the potential to alter the course of pain with a single treatment. DNA decoys are oligonucleotides that specifically inhibit the activity of certain transcription factors. AYX2 binds and inhibits Krüppel-like transcription factors (KLF) in the DRG-spinal cord. The goal of this Phase 1 proposal is to advance AYX2 toward an IND submission, allowing for human clinical trials. We propose in Aim 1 to characterize AYX2 pharmacokinetics in the cerebrospinal fluid and plasma and its distribution in the DRG, spinal cord and brain following an IT injection. With this information, AYX2 will be tested in a panel of complementary toxicology studies in Aim 2 to allow for final IND-enabling studies, supported by Phase 2 of the grant. This research will accelerate development of AYX2 as a novel drug candidate for the non-opioid treatment of pain.

Disruptions in make-up of the microbiome are associated with disorders characterized by chronic pain and inflammation, such as rheumatoid arthritis and fibromyalgia. The gut microbiome has immune and metabolic effects, and human gut-derived bacteria may be a source of novel, safe, and non-addictive pain treatments. However, connections between gut and pain signals, known as the “gut–pain axis,” are still poorly understood. This study aims to identify human-gut-native bacteria that i) interact with known pain targets in lab studies, ii) test their activity and analgesic/anti-inflammatory potential in an animal model, and iii) develop a computational approach to predict microbial-genetic effects on pain signals.

Approximately 20% of patients who undergo surgery develop chronic pain, or Chronic Postsurgical Pain (CPSP). CPSP is highly associated with impaired functional recovery and persistent opioid use and dependence, and current standard postoperative multimodal analgesia is only moderately effective for its prevention. This study aims to determine whether the use of ketamine during and/or after surgery prevents Post-Mastectomy Pain Syndrome (PMPS), one of the most common CPSP conditions. Ketamine is a low-risk treatment option that is easy to implement in a wide range of clinical settings. If successful, this treatment could improve postoperative pain management in individuals undergoing mastectomy and help combat the opioid epidemic.

Neuropathic pain conditions are exceedingly difficult to treat, and novel non-opioid analgesics are desperately needed. Receptomic and unbiased transcriptomic approaches recently identified the orphan G-protein coupled receptor (oGPCR), GPR160, as a major oGPCR whose transcript is significantly increased in the dorsal horn of the spinal cord (DH-SC) ipsilateral to nerve injury, in a model of traumatic nerve-injury induced neuropathic pain caused by constriction of the sciatic nerve in rats (CCI). De-orphanization of GPR160 led to the identification of cocaine- and amphetamine-regulated transcript peptide (CARTp) as a ligand which activates pathways crucial to persistent pain sensitization. This project will test the hypothesis that CARTp/GPR160 signaling in the spinal cord is essential for the development and maintenance of neuropathic pain states. It will also validate GPR160 as a non-opioid receptor target for therapeutic intervention in neuropathic pain, and characterize GPR160 coupling and downstream molecular signaling pathways underlying chronic neuropathic pain.

This study aims to address critical gaps and unmet therapeutic needs of chronic low back pain (CLBP) patients using a next-generation deep brain stimulation (DBS) device with directional steering capability to engage networks known to mediate the affective component of CLBP. Researchers will utilize patient-specific probabilistic tractography to target the subgenual cingulate cortex (SCC) to engage the major fiber pathways mediating the affective component of chronic pain. The objective is to conduct an exploratory first-in-human clinical trial of SCC DBS for treatment of medically refractory CLBP. The research team aims to: (1) assess the preliminary efficacy of DBS of SCC in treatment of medically refractory CLBP; (2) demonstrate the safety and feasibility of SCC DBS for CLBP; and (3) develop diffusion tensor imaging–based blueprints of response to SCC DBS for CLBP.

Overreliance on opioids to treat chronic pain has been a contributor to the increase in individuals experiencing opioid addiction. This project aims to develop an innovative treatment approach for chronic pain that targets the cannabinoid receptor 1 (CB1R) to block the sensation of pain. The approach seeks to identify molecules that interact with a different part of the CBR1 receptor than do endocannabinoids and the primary active component of cannabis, tetrahydrocannabinol. Molecules that bind to and activate CBR1 in this different way (at an “allosteric” site) may produce nerve signaling that might differ from the effects of cannabis and endocannabinoids. This redirection of signaling pathways could help eliminate the risk of adverse effects observed with natural cannabinoids and other CBR1-binding molecules. The goal of this project is to identify a CB1R allosteric molecule, conduct studies toward obtaining federal permission to develop it as a medication, and to test it in a Phase I clinical study.

Many non-opioid drugs target G Protein-Coupled Receptors (GPCRs), a family of proteins involved in many pathophysiological processes including pain, fail during clinical trials for unknown reasons. A recent study found GPCRs not only function at the surface of nerve cells but also within a cell compartment called the endosome, where their sustained activity drives pain. This study will build upon this finding and test whether the clinical failure of drugs targeting plasma membrane GPCRs is related to their inability to target and engage endomsomal GPCRs (eGPCRs). This study will use stimulus-responsive nanoparticles (NP) to encapsulate non-opioid drugs and selectively target eGPCR dyads to investigate how eGCPRs generate and regulate sustained pain signals in neuronal subcellular compartments. This study will also validate eGCPRs as therapeutic targets for treatment of chronic inflammatory, neuropathic and cancer pain. Using NPs to deliver non-opioid drugs, individually or in combinations, directly into specific compartments in nerve cells could be a potential strategy for new pain therapies.

It is unclear what changes in the brain mediate the development of chronic pain from acute pain and how chronic pain may change responses to opioid reward for the altered liability of opioid abuse under chronic pain. Preliminary studies have found that Dnmt3a, a DNA methyltransferase that catalyzes DNA methylation for gene repression, is significantly downregulated in the brain in a time-dependent manner during the development of chronic pain and after repeated opioid treatment. This project will investigate whether Dnmt3a acts as a key protein in the brain for the development of chronic pain, and whether Dnmt3a could be a novel epigenetic target for the development of new drugs and therapeutic options for the treatment of chronic pain while decreasing abuse liability of opioids.

Chronic pain is a major health burden associated with immense economic and social costs. Predictive biomarkers that can identify individuals at risk of developing severe and persistent pain, which is associated with worse disability and greater reliance on opioids, would promote aggressive, early intervention that could halt the transition to chronic pain. The applicant’s team uncovered evidence of a unique cortical biomarker signature that predicts pain susceptibility (severity and duration). This biomarker signature could be capable of predicting the severity of pain experienced by an individual minutes to months in the future, as well as the duration of pain (time to recovery). Analytical validation of this biomarker will be conducted in healthy participants using a standardized model of the transition to sustained myofascial temporomandibular pain. Specifically the biomarker signature will be tested for its ability to predict an individual’s pain sensitivity, pain severity, and pain duration and will perform initial clinical validation.

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.

Inhaled nitrous oxide, N₂O, is used in emergency departments in Europe to treat pain associated with sickle cell disease as well as for labor, painful fractures, and to manage serious gynecological pain. It is not a viable therapeutic option for home use for reasons such as poor dosing control, potential inhalation equipment issues, and variability in patient ventilation and lung absorption. This project seeks to optimize, characterize, and develop an oral formulation of N₂O that could be used by patients at home for unpredictable and severe episodes of pain associated sickle cell disease. Once developed, the new oral formulation of N₂O will be evaluated to determine whether it or an optimized version is ready for more clinical testing.