Funded Projects

Chronic pain diminishes the quality of life for millions of patients, and new drugs that have better efficacy and/or fewer side effects are needed. A promising target is the sphingosine-1-phosphate (S1P) receptor system, which mediates central nervous system (CNS) neuromodulatory functions. FTY720-phosphate, the active metabolite of FTY720 (FTY), acts as an agonist at four of the five S1P receptors (S1P1, 3, 4, 5). We propose that the S1P1 receptor is a target for treatment of neuropathic pain. We will test whether S1P1 receptors mediate anti-hyperalgesic effects in a mouse neuropathic pain model. The specific aims are to: 1) determine the role of S1P1Rs in alleviation of neuropathic pain by S1PR ligands; 2) determine the role of FTY-induced S1PR adaptation in FTY-mediated reversal of neuropathic pain; and 3) determine the role of S1P and S1P1 receptors in spinal glia in CCI-induced neuropathic pain and its reversal by FTY.

Therapeutic virtual reality (VR) has emerged as a promising and evidence-based treatment modality for musculoskeletal pain, including chronic low back pain (cLBP). Users of VR wear a pair of goggles with a close-proximity stereoscopic screen that creates a sensation of being transported into lifelike, three-dimensional worlds. By stimulating the visual cortex while engaging other senses, VR modulates the user’s processing of nociceptive stimuli. Functional magnetic resonance imaging (fMRI) of the brain reveals that VR has similar effects on the sensory and insular cortex as opioids, and head-to-head trials show that VR achieves similar or greater analgesia as hydromorphone. Since there are few data regarding long-term efficacy and safety of VR in cLBP, this study will measure patient-reported outcomes, biometric outcomes, and opioid use in nonspecific cLBP patients under various experimental conditions using VR therapy.

Non-steroidal anti-inflammatory drugs (NSAIDs) are a first line pharmacologic pain therapy for chronic musculoskeletal pain, and rheumatoid arthritis (RA) and moderate to severe osteoarthritis (OA) specifically. However, insufficient pain relief by NSAID monotherapy has encouraged the use of combination therapy. Combinations of NSAIDs plus weak opioids are widely used although objective evidence for efficacy is limited and they have many adverse events.  A growing body of evidence suggests that ?2/?3 subtype-selective positive allosteric modulators (PAM) of the ?- aminobutyric acid A receptor (GABAAR) may effectively restore central pain regulatory mechanisms thus providing effective relief of chronic pain with reduced prevalence and severity of side-effects.  Based on these promising preliminary studies and considerable supporting literature data, the research team will test the hypothesis that combination dosing of TPA-023B with an NSAID will work synergistically to suppress the acute and chronic pain components of chronic musculoskeletal pain. 

This study will (1) test pharmacologic and behavioral strategies to improve OUD pharmacotherapy treatment retention and to improve outcomes among patients who have been successfully stabilized on OUD medications and want to stop medication and (2) identify predictors of successful outcome and develop a stage model of relapse risk.

The chronic low back pain (cLBP) subgroup with comorbid depression or anxiety disorders, known as high negative affect (NA), needs better non-opioid, comprehensive pain treatment options. Data shows that the combination of antidepressants (AD) and fear avoidance physical therapy is more efficacious at improving pain, function, depression, and anxiety in cLBP patients with high NA than each treatment alone or a control condition. Research also finds that an enhanced fear avoidance rehabilitation protocol (EFAR; fear avoidance-based physical therapy, pain education, and motivational messaging) further improves outcomes. To address the unmet needs of cLBP patients with high NA, this study will test in a randomized trial whether the combination of AD and EFAR is more effective than each treatment alone at relieving pain, improving function, combating depression, and preventing opioid misuse. This multimodal combination approach of pharmacotherapy and behavioral therapy is novel to the field and has the potential to shift current treatment paradigms.

Although there are effective prevention and treatment programs and services to address opioid misuse, opioid use disorder (OUD), and overdose, gaps remain between those needing and those receiving prevention and treatment, in part because of a need to better understand how to make these programs and services most effective at a local level. The National Institutes of Health (NIH) and the Substance Abuse and Mental Health Services Administration (SAMHSA) launched the HEALing Communities Study to generate evidence about how tools for preventing and treating opioid misuse and OUD are most effective at the local level. This multisite implementation research study will test the impact of an integrated set of evidence-based practices across health care, behavioral health, justice, and other community-based settings. The goal of the study is to reduce opioid-related overdose deaths by 40 percent over three years. As the Data Coordinating Center, RTI will provide coordination and facilitate communications to unite the HEALing Communities Study research centers into a cohesive research cooperative.

Although effective, current pharmacotherapies for opioid use disorder (OUD) present serious limitations. For example, methadone, a mu opioid receptor (MOP) full agonist, has significant abuse liability and causes withdrawal after chronic use, while buprenorphine (Bup), an MOP partial agonist and kappa opioid receptor (KOP) antagonist, produces limited respiratory depression and is less effective than methadone in reducing drug use, craving, and relapse. To address the limitation of currently available MATs, this project uses a phased plan that will fast-track the IND development of a next-generation medication for OUD based on small-molecule compounds targeting the nociception opioid receptor (NOP)—with no misuse or dependence liability—that have shown promising efficacy in reducing oxycodone intake in rhesus monkeys trained to self-administer, with efficacies similar to that of buprenorphine. The project’s ultimate goal is to file an IND application for an NOP agonist as a promising new approach to treat illicit and prescription OUD that may offer an alternative to buprenorphine.

Although medications are available to treat opioid use disorder (OUD), adherence with treatment programs remains a problem. Nalmefene is an opioid receptor antagonist that was previously approved for treatment of opioid overdose–induced respiratory depression that has a longer duration of action than naloxone. AP007 is a unique formulation of nalmefene-loaded poly(lactic-co-glycolic acid) (PLGA) microparticles that when injected intramuscularly continually releases an effective dose of nalmefene and thus reduces opioid cravings in OUD patients. This group is developing AP007 and will have a lead formulation selected based on in vitro release kinetics data and in vivo pharmacokinetics data in rats. The objectives of the project are to determine safety and efficacy of AP007 in a swine opioid use/withdrawal model, preliminary safety in a first-in-human Phase 1 study, and preliminary efficacy in a Phase 2a multidose study. These results will be used to develop Phase 2 human and Phase 3 clinical studies.

The opioid overdose epidemic is increasingly affecting urban, poor and predominantly minority populations in the U.S., including Washington, D.C., as indicated by rapidly increasing overdoses clustered in medically underserved, economically disadvantaged, largely African American areas of the District and many of the nation’s other largest cities. This study seeks to (1) develop, implement and conduct a preliminary evaluation of an integrated, community-based collaborative care model, employing peer recovery coaches and telepsychiatry services, to improve utilization and effectiveness of MOUD in Federally Qualified Health Centers (FQHCs) and (2) use a community-based participatory research approach to develop, implement and conduct a preliminary evaluation of outreach, engagement and recovery support interventions in nontraditional community settings (e.g., grassroots community groups, churches or religious organizations, soup kitchens, black barber shops or nail or hair salons).

This proposal would address barriers to the NP’s ability to prescribe buprenorphine by incorporating waiver education into NP final semester curriculum. The initial eight hours of training would be provided to students in a face-to-face classroom setting or via live video streaming. The remaining 16 hours would be completed by the NP students through online modules offered by the AANP. Trained NP students would be eligible for one year of peer-to-peer mentorship and inclusion in the MUSC Project ECHO tele-mentoring for new providers. Outcomes to be tracked would be the number of NPs trained who obtain their waiver and the number of individuals treated with MOUD by the NPs trained. Secondary data collected would offer insight into wavier obtainment process and determine need for mentorship for newly waivered providers.

TWIK-related spinal cord K+ (TRESK) channel is abundantly expressed in all primary afferent neurons (PANs) in trigeminal ganglion (TG) and dorsal root ganglion (DRG), mediating background K+ currents and controlling the excitability of PANs. TRESK mutations cause migraine headache but not body pain in humans, suggesting that TG neurons are more vulnerable to TRESK dysfunctions. TRESK knock out (KO) mice exhibit more robust behavioral responses than wild-type controls in mouse models of trigeminal pain, especially headache. We will investigate the mechanisms through which TRESK dysfunction differentially affects TG and DRG neurons. Based on our preliminary finding that changes of endogenous TRESK activity correlate with changes of the excitability of TG neurons during estrous cycles in female mice, we will examine whether estrogen increases migraine susceptibility in women through inhibition of TRESK activity in TG neurons. We will test the hypothesis that frequent migraine attacks reduce TG TRESK currents.

Functional selectivity is a term used to describe the ability of drugs to differentially regulate the activity of multiple signaling cascades coupled to the receptor. The underlying mechanism for functional selectivity is based upon the formation of ligand-specific receptor conformations that are dependent upon ligand structure. Functional selectivity has the potential to revitalize the drug discovery/development process. Ligands with high efficacy for specific signaling pathways (or specific patterns of signaling) that mediate beneficial effects, and with minimal activity at pathways that lead to adverse effects, are expected to have improved therapeutic efficacy. We propose to demonstrate that ligand efficacy for specific signaling pathways associated with antinociception can be finely tuned by structural modifications to a ligand. We propose to use U50,488 and Salvinorin-A (Sal-A) as scaffolds to develop functionally selective analogs that maintain high efficacy for signaling pathways that lead to antinociception and minimize activity toward anti-antinociceptive signaling pathways.