Funded Projects

Epidural/spinal administration of analgesics such as opioids, ziconotide and local anesthetics have profound efficacy in some of the most intractable pain conditions such as severe neuropathic pain after failed back surgery, cancer pain and post-operative pain after major abdominal/thoracic surgeries. Contulakin G (CGX) is a snail venom derived peptide that has homology with mammalian neurotensin and was shown to be safe in humans in preliminary studies. A small pilot study demonstrated CGX?s analgesic effect in some patients with spinal cord injury-associated pain. Preliminary findings from mechanistic studies in rodents identified neurotensin receptor 2 (NTSR2) as the mediator for analgesic effects of CGX. This project aims to validate spinal NTSR2 as an analgesic target utilizing three species (rat, mice and human), and two pain models (neuropathic pain and post-surgical pain). The project will utilize pharmacological and gene editing tools such as CRISPR-Cas9 and will include assessment of both sensory and affective measures of pain. A two-site parallel confirmation study is designed based on multisite clinical trials to further authenticate spinal NTSR2 as an analgesic target. Successful completion of this project could lead to the development of a non-opioid spinal analgesic that has high translational potential.

A more thorough understanding of neuropathic pain is critical for developing new target-specific medications. Researchers know that peripheral nerve injury changes various cell processes that affect two ion channels linked with chronic pain. Preliminary studies indicate that molecular changes known as phosphorylation to the collapsin response mediator protein 2 (CRMP2), one of five intracellular phosphoproteins, promotes abnormal excitability in the brain region that contributes to neuropathic pain. This project aims to develop small molecule inhibitors of CRMP2 phosphorylation as potential therapeutics for pain.

The research team has developed ultrasonic drug uncaging for neuroscience, in which neuromodulatory agents are uncaged from ultrasound-sensitive biocompatible and biodegradable drug-loaded nanocarriers. This project will clinically translate ultrasonic ketamine uncaging for chronic pain therapy. In the UG3 phase, the research team will scale our nanoparticle production processes to human scales and adapt them to pharmaceutical standards. In the UH3 phase, they will complete a first-in-human evaluation of the safety and efficacy of ultrasonic ketamine uncaging by quantifying how much ketamine is released relative to the ultrasound dose and assessing whether the uncaged ketamine can modulate the sensitivity and affective response to pain, in patients suffering from chronic osteoarthritic pain. This project aims to yield a novel, noninvasive, non-opioid therapy for chronic pain that maximizes the therapeutic efficacy of ketamine over its side effects, by targeting its action to a critical hub of pain processing.

Current medications for chronic pain are largely ineffective and rely heavily on opioids, one contributor to the nation’s opioid crisis. The endocannabinoid system that consists of cannabinoid receptors (CB1R and CB2R) and their endogenous ligands is a natural pathway in the human body and has emerged as an alternative target for developing new pain medications with few side effects. Current molecules that bind to CB1R in the brain and spinal cord have psychoactive side effects, limiting their therapeutic use for treating chronic pain. This study aims to develop new molecules to bind to CB1R tightly and selectively, are metabolically stable, and are also unable to enter the brain.

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 research seeks to develop a high-resolution spinal cord stimulation therapy for treating chronic neuropathic pain of the lower extremities, groin, and lower back. Systems that use wireless communication methods require robust strategies to prevent various forms of cyberattacks on implantable devices. The focus of this project's research will be to develop a new cybersecurity risk-reduced architecture for Bluetooth low-energy implant communication.

There is currently no recognized way of accurately predicting who will recover from post-traumatic headache (PTH) during the acute phase following concussion and who will go on to develop persistent post-traumatic headache (PPTH), a condition that is difficult to treat effectively. Clinical experience suggests that early treatment is most effective, before headache patterns become persistent, but treating all patients with PTH would expose some patients to unnecessary treatment. Clinicians lack the information needed to make informed treatment decisions. Therefore, the study goals are to develop a prognostic biomarker signature for PPTH using clinical data and structural and functional brain neuroimaging and to assess the predictive accuracy of an ensemble biomarker signature for the early identification of patients at high risk for PPTH. This study can be translated into clinical practice and integrated into PTH clinical trials for early identification of those individuals who are at high risk for PPTH.

The goal of this project is to generate data and reagents that help uncover critical functions of the poorly characterized members of ion channels. It focuses on co-perturbation of ion channel genes and their interacting genetic components as opposed to singly altering ion channel genes in mouse models. This approach will validate our proteomics approaches in the most definitive manner: in vivo. We see in vivo exploration as an essential step to evaluate ion channel function. Our major aims include mapping ion channel interactions and complexes using a high-throughput proteomics platform at UCSF. These data will be interrogated using integrative approaches established by the Monarch Initiative, where biochemical interactions will be validated and prioritized for further study. Another major aim is function-centric: We use mouse models for elucidation of human disease mechanisms, where we embrace a genetic interaction scheme to uncover ion channel redundancy and polygenic effects.

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.

Multi-protein complexes have emerged as a mechanism for spatiotemporal specificity and efficiency in the function and regulation of cellular signals. 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 AKAP79/150. We will probe complexes containing AKAP79/150 and three different channels critical to nervous function: KCNQ/Kv7, TRPV1, and CaV1.2. We will use"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. We hypothesize that AKAP79/150 brings several of these channels together to enable functional coupling, which we will examine by patch-clamp electrophysiology of the neurons. Since all three of these channels bind to AKAP79/150, we hypothesize that they co-assemble into complexes in neurons and that they are dynamically regulated by other cellular signals.

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.

Neck pain is the fourth leading cause of disability and also a significant cause of cervicogenic headaches. Many of the currently available neck pain treatments are invasive with associated risks and complications, particularly because of the complex anatomy. Magnetic resonance guided focused ultrasound, a novel, completely noninvasive technique, can precisely target spinal facet joints to help ameliorate neck pain, potentially transforming the current practices. The goal of this study is to develop a cervical spine-specific device and demonstrate its safety and efficacy on targeting cervical sensory fibers and the third occipital nerve. The results of these studies will provide an understanding on how to best use this technology for chronic neck pain as well as a basis for translation into human use.