Funded Projects

An important step for identifying new, non-addictive chronic pain treatments is the search for new, non-opioid molecular targets that reflect the human condition. Recent findings show an increase in levels of two proteins (calcium channel alpha-2delta-1 subunit and thrombospondin) in sensory and spinal cord neurons after nerve injury. This increase is associated with the development of neuropathic pain. This project will determine if chronic injury to key nerve fibers involved in pain cause changes in rat behavior that indicate altered mood. These nerve fibers include the trigeminal nerve that communicates pain, touch, and temperature sensations from the face to the brain and the L5/6 spinal nerves often associated with back and leg pain. This research will also test whether small protein-like molecules (peptides) that block calcium channel alpha-2delta-1 subunit and thrombospondin also block the mood-related behaviors.

Postoperative ileus (POI) following gastrointestinal (GI) surgery leads to significant patient morbidity and prolonged hospitalizations. Recent studies have demonstrated that intestinal manipulation and surgical trauma activate inflammatory macrophages (M?) and release inflammatory mediators such as nitric oxide (NO) to inhibit intestinal smooth muscle cells in POI. Intestinal M? are a highly heterogeneous and dynamic population in the innate immune system. Preliminary studies show that transient receptor potential vanilloid 4 (TRPV4) channel, a molecular sensor of tissue damage and inflammation, is exclusively expressed by the F4/80+/CD206+ intestinal anti-inflammatory M2 M?. Activation of TRPV4 produces an intestinal contractile response and improves GI transit in a mouse model of POI. The current proposal aims to elucidate the cellular and molecular mechanisms underlying the activation of TRPV4 in the intestinal M2 M?.

Previous studies found that African American (AA) and low socioeconomic status (SES) patients are less likely to receive guideline-concordant pain care relative to White and high SES patients. According to research and theory, enhancing clinician perspective-taking is a promising strategy for improving the care of AA and low SES patients. We have developed an innovative methodology that utilizes computer-simulated patients and environments to assess, understand, and remediate pain treatment disparities. Our approach allows for the intervention to be individually tailored to each trainee, thereby enhancing its impact. It also allows for individual trainees to gain exposure to a greater range of racially and socioeconomically diverse patients than can normally be obtained in traditional training settings. We hypothesize that our perspective-taking intervention will increase trainees’ knowledge of their own biases, enhance trainees’ empathy toward patients, and reduce trainees’ anxiety/threat toward patients, and that these changes will reduce pain treatment disparities.

Data suggest that members of minority groups are more likely to develop chronic pain and to have greater pain burden. We will identify a set of promising intervention targets for reducing or eliminating racial/ethnic pain disparities. We will interview adult survivors of serious physical injury, comprised of roughly equal proportions of African-Americans (AA), Latinos, and non-Latino Whites (NLW), and examine their medical records for information on injury severity and medication use in-hospital. Our aims are to determine whether: 1) AA and Latino physical injury survivors experience more severe pain relative to NLW; 2) AA and Latino injury survivors experience greater pain burden relative to NLW counterparts; 3) differences in pain severity burden are linked to a set of target candidates for interventions; and (4) pain outcomes in at-risk minority groups can be linked to a set of target candidates for group-tailored interventions to reduce pain severity and pain burden.

The System of Safety (SOS) represents an opportunity to study the implementation of best practice suicide-related care processes that embody the Zero Suicide Essential Elements of Care across emergency departments, inpatient medical and behavioral health units, and primary care clinics associated with a large healthcare system. This effectiveness trial will use a stepped wedge design across a total of 39 clinical units. Aim 1 will measure suicide risk screening and screening's impact on risk identification. Aim 2 will measure the effective implementation of clinician-administered interventions, such as safety planning with means restriction counseling, on suicide, suicide attempts, and suicide-related acute healthcare. Exploratory aims will examine mechanisms of action, moderators, economics, and population effects of the intervention. This study's innovative approach positions it for a significant impact on the fields of suicide prevention, CQI, and effectiveness trial design and analysis.

The project will address gaps in both risk identification and clinical management by utilizing comprehensive clinical data from a mature health information exchange containing more than 2.3 million patients across the spectrum of clinical care (hospitals, primary care, specialty care, community health centers, urgent care) to develop a statistically robust method to measure suicide risk associated with prescription opioid use. First, the team will couple data fusion techniques with machine learning-based approaches in identifying the clinical and demographic characteristics associated with elevated risk of suicidal behavior among prescription opioid users. Second, the team will develop clinical profiles of patients with higher risk of suicidal behavior associated with prescription opioids, and to incorporate these profiles in a clinical decision support platform that can be used for identification and intervention at the point of care. The clinical decision support tool developed under this proposal will provide a generalizable platform that could be extended to other more conventional opioid related outcomes such as OUD and overdose.

Paralleling overall population trends, opioid use has escalated among pregnant and postpartum women, particularly among those with co-occurring perinatal mood and anxiety disorders, yet treatment remains underutilized. Since 2008, health insurance coverage changes led to a dramatic expansion of behavioral health coverage by increasing coverage and extending federal parity protections to more than 60 million Americans. Characterizing the clinical and economic impacts of these unprecedented extensions of behavioral coverage on maternal and infant outcomes among women with perinatal opioid use, chronic pain, and suicidality with and without co-occurring perinatal mood and anxiety disorders will inform future policy and targeted interventions

Wound care procedures (WCPs), such as dressing changes, cause moderate to severe pain in 74% of patients, nearly half of whom experience severe pain. Mainstay recommendations to prevent pain during WCPs have focused on either administration of preventive and procedural analgesia or use of expensive, non-adherent dressings. However, it is unclear which patients to target for analgesia or expensive dressings, leading to their inappropriate over- or underuse. To achieve the aims of the study, a comprehensive set of wound, patient, and biological factors will be measured concurrently with pain during a dressing change among a sample of 450 inpatients with open wounds. A predictive model will be developed and biological mechanisms will be examined using logistic regression. The proposed study has the potential to make significant contributions because clinicians will be able to target those patients requiring preventive pain control, thereby eliminating the spiraling impact of painful procedures on nociceptor sensitization.

Many chronic pain conditions are dependent upon activity of the sympathetic nervous system. Sympathetic blockade is used clinically in chronic pain conditions, but the clinical and preclinical evidence for this practice is incomplete. We propose that certain pathological pain conditions require intact sympathetic innervation of the sensory nervous system at the level of the dorsal root ganglion (DRG) and that release of sympathetic transmitters enhances local inflammation and leads to pain. Our preliminary data show large, rapid, and long-lasting reduction of pain behaviors and inflammatory responses following a"microsympathectomy" (mSYMPX) in both neuropathic and inflammatory pain models. Our aims are to: 1) characterize the effects of mSYMPX on pain and on local inflammation in the DRG; 2) explore the molecular mechanisms for sympathetic regulation of inflammatory responses in the DRG; and 3) assess the functional role of sympathetic transmitters in the sympathetically mediated inflammatory responses in the DRG.

Multi-protein complexes have emerged as a mechanism for spatiotemporal specificity and efficiency in the function and regulation of myriad cellular signals. In particular, many ion channels are clustered either with the receptors that modulate them, or with other ion channels whose activities are linked. Often the clustering is mediated by scaffolding proteins, such as the AKAP79/150 protein that is a focus of this research. This research will focus on three different channels critical to nervous function. One is the"M-type" (KCNQ, Kv7) K+ channel that plays fundamental roles in the regulation of excitability in nerve and muscle. It is thought to associate with Gq/11- coupled receptors, protein kinases, calcineurin (CaN), calmodulin (CaM) and phosphoinositides via AKAP79/150. Another channel of focus is TRPV1, a nociceptive channel in sensory neurons that is also thought to be regulated by signaling proteins recruited by AKAP79/150. The third are L-type Ca2+ (CaV1.2) channels that are critical to synaptic plasticity, gene regulation and neuronal firing. This research will probe complexes containing AKAP79/150 and these three channels using"super-resolution" STORM imaging of primary sensory neurons and heterologously-expressed tissue-culture cells, in which individual complexes can be visualized at 10-20 nm resolution with visible light, breaking the diffraction barrier of physics. The researchers hypothesize that AKAP79/150 brings several of these channels together to enable functional coupling, which the researchers will examine by patch-clamp electrophysiology of the neurons. Förster resonance energy transfer (FRET) will also be performed under total internal reflection fluorescence (TIRF) or confocal microscopy, further testing for complexes containing KCNQ, TRPV1 and CaV1.2 channels. Since all three of these channels bind to AKAP79/150, the researchers hypothesize that they co-assemble into complexes in neurons, together with certain G protein-coupled receptors. Furthermore, the researchers hypothesize these complexes to not be static, but rather to be dynamically regulated by other cellular signals, which the researchers will examine using rapid activation of kinases or phosphatases. Several types of mouse colonies of genetically altered AKAP150 knock-out or knock-in mice will be utilized.

Migraine is the most common neurological disorder. Currently available treatments fail to effectively manage migraine in most patients. Development of new therapeutics has been slow due in large part to a poor understanding of the underlying pathology of migraine. Endogenous proteases, released in the meninges by resident mast cells, have been proposed as a potential driver of migraine pain via an action on protease activated receptor type 2 (PAR2). The central hypothesis is that PAR2 expression in nociceptors that project to the meninges plays a key role in the pathogenesis of migraine pain. The aims are to: 1) use the established PAR2 development pipeline to design new PAR2 antagonists with improved drug-like properties; 2) use pharmacological tools in a novel mouse migraine model to further understand the potential role of PAR2 in migraine; and 3) use mouse genetics to study the cell type–specific role of PAR2 in migraine pain.

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.

Neuropathic pain conditions are difficult to treat, and novel non-narcotic analgesics are desperately needed. The G protein-coupled receptor 160 (GPR160) has emerged as a novel target for analgesic development, as GPR160 in the spinal cord may play a role in the transition from acute to chronic pain. Cocaine- and Amphetamine-Regulated transcript peptide (CARTp) was identified as a ligand for GPR160. Blocking endogenous CARTp signaling in the spinal cord attenuates neuropathic pain, whereas intrathecal injection of CARTp evokes painful hypersensitivity in rodents through GPR160-dependent extracellular signal-regulated kinase (ERK) and cyclic AMP response element-binding pathways (CREB). This project will isolate and biochemically characterize GPR160 and establish methods for biochemical characterization of GPR160 interaction with CARTp activator. Researchers will miniaturize and optimize biochemical assay and scale up protein production for future high throughput biochemical screening to identify potent inhibitors of GPR160 activation. These studies are critical for defining the molecular mechanism of CARTp/GPR160 interactions and initiating large-scale screens for new inhibitors to develop novel therapeutics.