Funded Projects

Neuropilin 1 receptor (NRP1) is a protein receptor that is active in neurons and is hypothesized to be a key mediator of sensory neuron sensitization that can lead to pain. This project will study the cellular mechanisms by which NRP1 leads to sensitization and which cell types—sensory neurons, microglia, or both—are responsible for NRP1’s role in pain. The findings can help validate NRP1 in sensory neurons and the spinal cord as a target to treat pain following nerve injury.

G protein-coupled receptors (GPCRs) are the largest family of transmembrane signaling proteins and play important roles in inflammation and pain. GPCR signaling is fast and temporary, making it hard to measure in clinical studies of potential drugs to interfere with the signaling. This research is using selectively designed nanoparticles to stimulate or block GPCRs toward identifying new treatments for oral cancer pain. This award will use a new nanoformulation approach to understand how nanoparticles affect nerve function by i) testing the effects of continuous release of a GPCR inhibitor in an oral cancer microenvironment and ii) investigating the influence of various physicochemical characteristics of nanoparticles on nerve function in an oral cancer microenvironment.

There is an urgent need to find new ways to treat chronic pain through better targeting of underlying biological processes. Research shows that flexible synapses within the amygdala brain region play a role in the progression of pain from acute to chronic, but the details are not fully understood. The receptor glutamate delta 1 helps to form and maintain synapses in the amygdala in inflammatory and neuropathic pain. This project will study how the shape and characteristics of glutamate delta 1 affect pain conditions that involve the amygdala, toward informing future development of pain medications. 

A major recent advancement for the field of pain research is the recognition of immune system dysregulation as a contributor to the most serious adverse consequences of pain from injury. Accumulating data from clinical and laboratory studies place the activation of B lymphocytes at the center of much of this work, particularly with respect to chronic pain and disability-related outcomes. Validation of this B cell hypothesis could lead directly to trials testing the efficacy of novel or existing immunomodulating agents on posttraumatic pain. To achieve these goals a well-validated core mouse model of limb fracture will be employed with additional studies to be conducted in incisional and nerve injury models to broaden the assessment of B cell mediated effects on pain. Age and sex will be included as variables to enhance rigor.

Spinal cord injury (SCI) impairs sensory transmission and leads to chronic, debilitating neuropathic pain. While our understanding of the development of chronic pain has improved, the available therapeutics provide limited relief. We will examine the peripheral immune and inflammatory response. Secondary inflammation in response to SCI is a series of temporally ordered events: an acute, transient upregulation of chemokines, followed by the recruitment of monocytes/macrophages and generation of an inflammatory environment at the lesion site in the spinal cord, but also surrounding primary nociceptors in the dorsal root ganglia (DRG). These events precede neuropathic pain development. Previous work indicates that after SCI, macrophage presence in the DRG correlates with neuropathic pain. We propose to study: 1) whether the phenotype of macrophages that infiltrate the DRG is different than those that persist chronically after SCI and 2) how manipulation of macrophage phenotype affects nociceptor activity and pain development.

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.

Spinal cord injury (SCI) impairs sensory transmission leading to chronic, debilitating neuropathic pain. While our understanding of the molecular basis underlying the development of chronic pain has improved, the available therapeutics provide limited relief. In the lab, we have shown the timing of exercise is critical to meaningful sensory recovery. Early administration of a sustained locomotor exercise program in spinal cord–injured rats prevents the development of neuropathic pain, while delaying similar locomotor training until pain was established was ineffective at ameliorating it. The time elapsed since the injury occurred also indicates the degree of inflammation in the dorsal horn. We have previously shown that chronic SCI and the development of neuropathic pain correspond with robust increases in microglial activation and the levels of pro-inflammatory cytokines. This proposal seeks to lengthen the therapeutic window where rehabilitative exercise can successfully suppress neuropathic pain by pharmacologically reducing inflammation in dorsal root ganglia.

The research team developed an in vitro multi-component joint on a chip (microJoint), in which engineered osteochondral complexes, synovium, and adipose tissues were integrated. This study will introduce sensory innervation into the microJoint and a neuron-containing microfluidic ally will be developed to innervate the microJoint. The osteoarthritis (OA) model will be created in the Neu-microJoint system. The research team will assess activation and/or sensitization of nociceptive afferents with electrophysiology, as well as neurite outgrowth. They will mechanically insult the Neu-microJoint and assess the emergence of “pain” in response to prolonged mechanical stress. Researchers will assess the impact of drugs used clinically for management of OA on OA models and will then use “omic” approaches to identify new biomarkers and therapeutic targets. Researchers will assess the impact of opioids—which they hypothesize will increase the rate of joint degeneration and potentiate the release of pain-producing mediators—on neural activity in the presence and absence of joint injury, as well as the integrity of all joint elements.

Researchers will develop a novel transcranial focused ultrasound (tFUS) device for pain treatment and establish its effectiveness for treating sickle cell disease (SCD) pain in humanized mice. The tFUS will target the specific cortical regions involved in SCD pain using a novel non-invasive electrophysiological source imaging technique. The project’s goals have several aims. Aim 1: Develop tFUS devices for pain treatment. The mouse-scale system will be designed to validate the therapeutic effect of stimulating the anticipated cortical targets. This will inform development of the simpler human-scale system, which will use models of the skull to select cost-effective transducers to reach the targets. Aim 2: Evaluate tFUS effectiveness and optimize stimulation parameters in an SCD mice model. Researchers will determine effective tFUS parameters to chronically reduce SCD pain in mice and validate this using behavioral measures. Aim 3: Use electrophysiological source imaging to target and trigger closed-loop tFUS in animal models. This aim also includes performing safety studies to prepare for human trials. The project will develop a transformative, noninvasive tFUS device to effectively and safely treat pain in SCD. 

Chronic pain is a debilitating condition for which there is a pressing need for safe, effective treatments. Neurostimulation therapies that target nerve structures such as the dorsal root ganglion (DRG) and the spinal cord, have shown promising results for treating chronic pain, but researchers don’t know how they work. This project focuses on two prevailing models used to explain the therapeutic effects of neurostimulation: the gate-control model in which pain signals are blocked from reaching the brain and the T-junction filtering model in which pain signals are blocked from reaching the spinal cord. Strategies will include innovative behavioral, electrophysiological, imaging, and computational modeling techniques. The results of these studies will help explain why neurostimulation therapies work and potentially offer new treatment strategies for improved pain relief.

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.

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.  

This project will identify molecular characteristics of human sensory neurons and non-neuronal cells from the human dorsal root ganglia. This structure located outside the spinal cord is integrally involved in communicating pain signals to and from the brain. The research will use molecular approaches to characterize tissues obtained from organ donors and in patients who experience chronic pain. The findings will also help generate a connectivity map, or “connectome,” of nerve cell connections between the dorsal root ganglia of the spinal cord and the brain.