Funded Projects

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.

This International Cooperative Biodiversity Group application aims to discover and develop small molecule drug leads from cultured marine microbes and diverse coral reef organisms collected from Fiji and the Solomon Islands. Drug discovery efforts will focus on four major disease areas of relevance to the United States and low- and middle-income countries: infectious disease, including tuberculosis and drug-resistant pathogens; neglected tropical diseases, including hookworms and roundworms; cancer; and neurodegenerative and central nervous system disorders. Screening in these therapeutic areas will be performed in collaboration with two major pharmaceutical companies, two highly respected academic groups, and various testing centers and government resources that are available to facilitate drug discovery and development. The acquisition of source material for this program will be linked to biotic surveys, informed by ecological investigations addressing the chemical mediation of biotic interactions, and enriched using ecology-based strategies designed to maximize secondary metabolite production and detection.

The Philippine Mollusk Symbiont International Cooperative Biodiversity Group harnesses the vast biodiversity of the Philippines to discover new drugs to treat bacterial infections, parasitic infections, pain, and other neurological conditions and cancer, all of which are serious health problems in both the Philippines and the United States. The Republic of the Philippines represents a unique nexus of exceptional biodiversity, dense human population with pressing societal needs, consequent urgent need for conservation, and government commitment to education and technology to harness national human and natural resources for a sustainable future. Mollusks are one of the most diverse groups of marine animals, and their associated bacteria represent an unexplored trove of chemical diversity. Researchers will use an increasing understanding of the interactions between mollusk symbionts and their hosts to discover the most novel and useful molecules. The project will document and describe Philippine mollusk biodiversity and support training and infrastructure that provide the foundation for conservation of Philippine biodiversity.

An International Cooperative Biodiversity Group with an interdisciplinary leadership team of physicians, pharmacologists, evolutionary biologists, and chemists will discover and develop therapeutic agents produced by Brazilian symbiotic bacteria. The team will target three therapeutic areas: 1) infectious fungal pathogens, 2) Chagas disease and leishmaniasis, and 3) cancers of the blood. All three areas represent major threats to human health that need to be addressed with new therapeutic agents. Internationally, invasive fungal diseases kill more people than malaria or TB, while Chagas disease imposes a special burden on Brazil, killing as many Brazilians as TB. Leishmaniasis has now passed Chagas disease in the Brazilian population. Despite major improvements in cancer chemotherapy, cancer is projected to result in 8 million deaths internationally this year (13% of all deaths, WHO) and an estimated 13 million per year by 2030.

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?.

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.

The clinical utility of opioids for pain treatment is limited by its risk for developing opioid usage disorders (OUD). These untoward effects impose a severe burden on society and present difficult therapeutic challenges for clinicians. We propose to extend our cerebral organoid MPS to facilitate the investigation of neuronal response to opioids and identify cellular and molecular signatures in patients vulnerable to OUD. We have assembled a team with complementary expertise in clinical characterization of OUD, cerebral organoid MPS modeling, single cell RNA-seq technology, and functional characterization of neurons in a mesolimbic reward system to test the hypothesis that midbrain MPS is a clinically relevant pre-clinical model for study of opioid usage disorder.

This project will design and test optimized temporal patterns of stimulation to improve the efficacy of commercially available spinal cord stimulation (SCS) systems to treat chronic neuropathic pain. Researchers will build upon a validated biophysical model of the effects of SCS on sensory signal processing in neurons within the dorsal horn of the spinal cord to better understand how to improve the electrical stimulus patterns applied to the spinal cord. They will use sensitivity analyses to determine the robustness of stimulation patterns to variations in electrode positioning, selectivity of stimulation, and biophysical properties of the dorsal horn neural network. Researchers will demonstrate improvements from these new stimulus patterns by 1) measuring their effects on pain-related behavioral outcomes in a rat model of chronic neuropathic pain and by 2) quantifying the effects of optimized temporal patterns on spinal cord neuron activity. The outcome will be mechanistically derived and validated stimulus patterns that are significantly more efficacious than the phenomenologically derived standard of care patterns; these patterns could be implemented with either a software update or minor hardware modifications to existing SCS products.

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 is a debilitating affliction present in 26% of diabetic patients, with substantial impact on the quality of life. Despite this significant impact and prevalence, current therapies for painful diabetic neuropathy (PDN) are only partially effective, and the molecular mechanisms underlying neuropathic pain in diabetes are not well understood. Our long-term goal is to elucidate the molecular mechanisms responsible for PDN in order to provide targets for the development of therapeutic agents. Our objective is to identify the molecular cascade linking CXCR4/SDF-1 chemokine signaling to DRG nociceptor hyper-excitability, neuropathic pain, and small fiber degeneration. Our aims will determine: 1) the ion-channel current profile of the nociceptor hyper-excitable state produced by CXCR4/SDF-1 signaling in PDN; 2) the gene expression profile of the nociceptor hyper-excitable state produced by CXCR4/SDF-1 signaling in PDN; and 3) the specific features of nociceptor mitochondrial dysfunction produced by CXCR4/SDF-1 signaling in PDN.

This project aims to develop a next-generation noninvasive neuromodulation system for non-addictive pain treatments. The research team will build an integrated system that uses magnetic resonance image-guided focused ultrasound (MRgFUS) stimulation to target pain regions and circuits in the brain with high precision. The system will use MR imaging to locate three pain targets commonly used in clinical pain treatments, to stimulate those targets with ultrasound, and to monitor responses of nociceptive pain circuits using a functional MRI readout. Three collaborating laboratories will tackle the goals of this project: (Aim 1) Develop focused ultrasound technology for neuromodulation in humans, compatible with the high magnetic fields in an MRI scanner. (Aim 2) Develop MRI technology to find neuromodulation targets, compatible with focused ultrasound transducers. (Aim 3) Validate the complete MRgFUS neuromodulation system in brain pain regions in nonhuman primates. By the end of the project, the research team will have a fully developed and validated MRgFUS system that is ready for pilot clinical trials in pain management.

Masticatory and spontaneous pain associated with temporomandibular joint disorders (TMJD) is a significant contributor to orofacial pain, and current treatments for TMJD pain are unsatisfactory. Pain-related transient receptor potential (TRP) channels, expressed by trigeminal ganglion (TG) sensory neurons, have been implicated in both acute and chronic pain and represent possible targets for anti-pain strategies. Using bite force metrics, we found TMJ inflammation-induced masticatory pain to be significantly, but not fully, reversed in Trpv4 knockout mice, suggesting the residual pain might be mediated by other pain-TRPs. Our gene expression studies demonstrated that TRPV1 and TRPA1 were up-regulated in the TG in response to TMJ inflammation in a Trpv4-dependent manner. We hypothesize that TRPV1 and TRPA1, like TRPV4, contribute to TMJ pain. Our specific aims will examine the contribution of TRPV1, TRPV4, and TRPA1 to pathogenesis of TMJD pathologic pain including assessment of the role of neurogenic inflammation.

Up to 5 percent of adolescents suffer from high-impact chronic musculoskeletal (MSK) pain, and only about 50 percent with chronic MSK pain who present for treatment recover. Current treatments for chronic MSK pain are suboptimal and have been tied to the opioid crisis. Discovery of robust markers of the recovery versus persistence of pain and disability is essential to develop more resourceful and patient-specific treatment strategies, requiring measurements across multiple dimensions in the same patient cohort in combination with a suitable computational analysis pipeline. Preliminary data has implicated novel candidates for neuroimaging, immune, quantitative sensory, and psychological markers for discovery. In addition, a standardized specimen collection, processing, storage, and distribution system is in place, along with expertise in machine learning approaches to extract reliable and prognostic bio-signatures from a large and complex data set. This project will facilitate risk stratification and a resourceful selection of patients who are likely to respond to current multidisciplinary pain treatment approaches.