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.

This research project will investigate the cannabinoid receptor 2 protein (CB2R) as a novel therapeutic target for opioid-induced respiratory depression caused by fentanyl, oxycodone, and heroin. This study will shed light on how the endocannabinoid system in the brainstem works to control breathing under normal conditions and during opioid-induced respiratory depression. The research aims to determine whether activation of the CB2R with a brain-penetrant CB2R-binding molecule is safe and clinically useful for treating opioid overdose prevention and reversal. This research will pave the way for discovering new medications that activate CB2R to reduce opioid-related deaths.

This U54 Center will use translational research from brain to bedside as a tool for medication development in cocaine use disorder. Preclinical and early phase I clinical PK/PD data will provide information for go/no-go decisions on phase II–III clinical trials with medications that show promise for cocaine use disorder. The overall goal of this research is to create a center that can provide important preclinical and early phase I clinical data to NIDA and pharmaceutical industry partners on novel compounds for cocaine use disorder. The aims related to the theme of the center will be achieved through two cores and three projects: The Administrative Core serves as a general resource for the other projects and the Educational Core, including oversight of fiscal and compliance matters, and will oversee interactions with outside entities, including NIDA and the pharmaceutical industry. The Educational Core will focus on training translational researchers for medication development for addictions across the two institutions.

New and safe therapeutic targets for treating opioid use disorder are needed. One promising approach is to test drugs currently approved by the U.S. Food and Drug Administration that work independently of the body’s opioid system. The medication memantine targets N-methyl-D-aspartate (NMDA) receptors in the brain, which have been implicated in the development and maintenance of addiction. This project will study a miniature version of multiple memantine molecules bound together that attaches only to NMDA receptors that are not within nerve connections. The research will evaluate the safety, misuse potential, and effectiveness of this molecular assembly in preclinical models. 

This project will develop a human cell-based model of the afferent pain pathway in the dorsal horn of the spinal cord. The research team’s approach utilizes novel human pluripotent stem cell (hPSC)-derived phenotypes in a model that combines 3D organoid culture with microfabricated systems on an integrated, three-dimensional (3D) microelectrode array. Researchers will establish the feasibility of a physiologically relevant, human 3D model of the afferent pain pathway that will be useful for evaluation of candidate analgesic drugs. They will then improve the physiological relevance of the system by promoting neural network maturation before demonstrating the system’s utility in modeling adverse effects of opioids and screening compounds to validate the model. Completion of the study objective will establish novel protocols for deriving dorsal horn neurons from hPSCs and create the first human microphysiological model of the spinal cord dorsal horn afferent sensory pathway.

Tens of thousands of people die each year from opioid overdose. Many of these people began taking opioids for pain. A critical treatment goal is to reduce the development of opioid dependence either by enhancing opioid analgesia so lower doses can be used or by blocking withdrawal symptoms. Current pharmacological treatments in these two categories, although effective, present serious limitations. The recent finding that reducing the signaling through mu-delta opioid heterodimers appears to enhance opioid antinociception and reduce dependence suggests that a blocker of mixed mu-delta receptors (MDOR antagonist) could be effective in reducing dependence by limiting opioid tolerance and preventing opioid withdrawal. This research group has developed a compound with that characteristic, called D24M, which preliminary studies have shown could reduce opioid dependence by enhancing opioid antinociception, reducing opioid tolerance, or directly inhibiting opioid withdrawal. They propose to extend this research by investigating whether it can reduce chronic pain in an animal model that mimics the clinical situation of pain patients who transition to dependence. If these studies are successful, they could lead to the development of an optimized drug ready for Investigational New Drug (IND) application and enable translational and clinical testing.

The opioid crisis has underscored the urgency of alleviating patients’ chronic low back pain (cLBP) with effective therapies, including evidence-based nonpharmacologic approaches. Mindfulness-based stress reduction (MBSR) is now recommended by the American College of Physicians for initial treatment of cLBP. A pragmatic clinical trial (PCT) will inform health care decision makers about whether this program can be implemented in a real-life clinical setting and measure its impact on outcomes. The OPTIMUM (Optimizing Pain Treatment In Medical settings Using Mindfulness) program will integrate and test an evidence-based mindfulness clinical pain program for patients with cLBP in the primary care provider (PCP) setting. It will be conducted with three health care system sites. Four hundred and fifty persons ? 18 years of age with cLBP will be randomized to OPTIMUM + PCP Usual Care or PCP Usual Care.

There is evidence that combining mindfulness-based interventions and peer recovery support services with medication-assisted therapy (MAT) to treat opioid use disorders (OUD) reduces substance use, cravings, symptoms of depression and anxiety, and relapse rates, and improves treatment retention, and relationships with treatment providers and social supports. The goal of the present study is to determine the effectiveness of a mindfulness-based intervention that also utilizes peer mentors in addition to professional substance abuse therapists (the Minds and Mentors program [MiMP]) in improving adherence to MAT for OUD and reducing relapse rates in a sample of individuals with OUD who are also on MAT versus a 12-step facilitation (TSF) program. The study hypothesizes that participants in MiMP will demonstrate better adherence; reduced relapse and cravings (primary outcomes measures); reduced depression, anxiety, and stress; improved social support (secondary outcomes measures); and reduced cortisol levels and reactivity to drug cues (exploratory outcome measures).

Optogenetics is a method of controlling nerve or brain activity using light-sensitive cell receptors (opsins). Optogenetics has been used in brain research for decades, allowing researchers to understand the brain and its associated disorders by selectively turning on and off specific nerve cells. This project will develop and refine use of an opsin and a light-stimulation device to control nerve cells contributing to the sensation of 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.