Funded Projects

Persistent pain states arising from inflammatory conditions, such as in arthritis, diabetes, HIV, and chemotherapy, exhibit a common feature in the release of damage-associated molecular pattern molecules, which can activate toll-like receptor-4 (TLR4). Previous studies suggest that TLR4 is critical in mediating the transition from acute to persistent pain. TLR4 as well as other inflammatory receptors localize to lipid raft microdomains on the plasma membrane. We have found that the secreted apoA-I binding protein (AIBP) accelerates cholesterol removal, disrupts lipid rafts, prevents TLR4 dimerization, and inhibits microglia inflammatory responses. We propose that AIBP targets cholesterol removal to lipid rafts harboring activated TLR4. The aims of this proposal are to: 1) determine whether AIBP targets lipid rafts harboring activated TLR4; 2) test whether AIBP reduces glial activation and neuroinflammation in mouse models of neuropathic pain; and 3) identify the origin and function of endogenous AIBP in the spinal cord.

We propose to develop a safe and effective nonopioid analgesic to treat neuropathic pain that targets an isoform of the voltage-gated sodium ion channel, NaV1.7. Voltage-gated sodium channels are involved in the transmission of nociceptive signals from their site of origin in the peripheral terminals of DRG neurons to the synaptic terminals in the dorsal horn. NaV1.7 is the most abundant tetrodotoxin-sensitive sodium channel in small diameter myelinated and unmyelinated afferents, where it has been shown to modulate excitability and set the threshold for action potentials. Development of systemic NaV1.7 inhibitors has been complicated by the challenge of achieving selectivity over other NaV isoforms expressed throughout the body. We have discovered a series of potent, state-independent NaV1.7 inhibitors that exhibit >1000-fold selectivity over other human isoforms. Work conducted under this program will support advancement of a lead candidate into clinical development as a therapeutic for neuropathic pain.

Effective development of non-addictive therapies for pain requires animal models that reflect the human condition. Unfortunately, currently used models have limitations and have not always done a good job of predicting what will work in human patients. This project will refine a new way of measuring pain-related behaviors in mice that takes advantage of more natural mouse behavior and is less influenced by experimenter biases and artifacts. The research will verify that the promising results hold up in several different types of pain and that different classes of clinically used pain medications are effective. They will also make sure the data can be reproduced by an outside laboratory. If successful, this will support the use of this new read-out for future pain therapy development.

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.

Epidural/spinal administration of analgesics such as opioids, ziconotide and local anesthetics have profound efficacy in some of the most intractable pain conditions such as severe neuropathic pain after failed back surgery, cancer pain and post-operative pain after major abdominal/thoracic surgeries. Contulakin G (CGX) is a snail venom derived peptide that has homology with mammalian neurotensin and was shown to be safe in humans in preliminary studies. A small pilot study demonstrated CGX?s analgesic effect in some patients with spinal cord injury-associated pain. Preliminary findings from mechanistic studies in rodents identified neurotensin receptor 2 (NTSR2) as the mediator for analgesic effects of CGX. This project aims to validate spinal NTSR2 as an analgesic target utilizing three species (rat, mice and human), and two pain models (neuropathic pain and post-surgical pain). The project will utilize pharmacological and gene editing tools such as CRISPR-Cas9 and will include assessment of both sensory and affective measures of pain. A two-site parallel confirmation study is designed based on multisite clinical trials to further authenticate spinal NTSR2 as an analgesic target. Successful completion of this project could lead to the development of a non-opioid spinal analgesic that has high translational potential.

This project supports a post-baccalaureate trainee develop skills needed to pursue a career in clinical pain research. The research will use molecular tools to study nerve, joint, muscle, and fascia tissues from individuals with chronic low back pain who had spine surgery. The research will include working with patients, designing clinical studies, and sharing results. 

Postoperative pain is a major contributor to the current opioid epidemic. Novel objective measures capable of personalizing pain care will enhance medical precision in prevention and treatment of postoperative pain. This project seeks to discover and validate a novel biosignature of the human pain experience, based on underlying IL-1 family cytokine activity and associated brain endogenous opioid function, that is readily quantifiable and clinically translatable to prevention and treatment of postoperative pain states. Specific aims will assess whether the novel biosignature will predict 1) experimentally induced pain during an experimental nociceptive pain challenge; 2) postoperative pain states with accuracy >75%, accounting for a wide range of variance in the human pain experience; and 3) postoperative pain states in an expanded clinically enriched sample.

Cerebral palsy (CP), the leading cause of childhood disabilities in the United States, refers to a group of neurological disorders that appear in infancy or early childhood and permanently affect body movement and muscle coordination. The experience of pain is one of the most common, poorly understood, and inadequately treated conditions in CP, impairing health and quality of life for both patients and caregivers. To understand why pain and motor dysfunction occur together, a model that accurately replicates both is needed. This project will validate an established, rabbit model of CP motor dysfunction for use in studying and developing effective treatments for CP-associated pain.

This project will use state-of-the-art technologies to analyze individual cells to characterize how human pain receptors communicate pain between the human dorsal root ganglia and the brain – including how the signals vary across diverse populations. This research will generate useful, high-quality human data about pain for further analysis and re-use by other scientific teams, toward identifying and prioritizing novel therapeutic targets for pain.

Endometriosis is an often-painful disorder in which uterine tissue grows outside the uterus. Treatment of endometriosis-associated pain involves use of opioids in many women. This project aims to study a culprit gene thought to be involved with the disorder (capillary morphogenesis gene or CMG2) as a target for new, nonopioid pain medications. The research will also clarify how CMG2 s affects endometriosis-associated pain to test the effects of new medications for endometriosis pain.

An extensive literature provides compelling evidence that selective antagonists or negative allosteric modulators (NAMs) of the metabotropic glutamate (mGlu) receptor, mGlu5, have exciting potential as a novel approach for treatment of multiple pain conditions that could provide sustained antinociceptive activity without the serious adverse effects and abuse liability associated with opioids. Researchers have developed a novel series of highly selective mGlu5 NAMs that are structurally unrelated to previous compounds, have properties for further development, and avoid the formation of toxic metabolites that were associated with previous mGlu5 NAMs. Based on existing preclinical models, as well as clinical trial data showing efficacy of an mGlu5 NAM in migraine patients, researchers anticipate that their compounds will have broad-spectrum analgesic activity in patients with a variety of chronic pain conditions.

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.

There is an urgent unmet need for more efficacious analgesics that act via a non-opioid pathway. Mitogen Activated Protein Kinase-interacting kinase 2 (MNK2) is an enzyme that has been implicated in pain signaling, and there is compelling evidence that inhibiting MNK2 has significant pain-reducing effects with few side-effects. Since MNK2 selective inhibitors have not yet been identified, selective inhibition of MNK2 with a small molecule has not been possible. The development of such compounds will enable studies that will illuminate key differences between MNK2 and MNK1. More importantly, from a therapeutic standpoint, highly selective MNK2 inhibitors may prove to have enhanced efficacy and a more favorable side-effect profile than molecules that inhibit both MNK2 and MNK1. This project will support the design and synthesis of at least one MNK2 inhibitor, with >100-fold selectivity over MNK1, that may be developed into a lead compound for treating neuropathic pain.