Faculty Bibliography

BACKGROUND:Oral cancer causes intense pain at the primary site, and such pain can impair oral functions. However, the underlying mechanisms for oral cancer pain are still not fully understood. In the present study, it is investigated whether programmed cell death protein 1 (PD-1) is involved in the development of oral cancer pain. METHODS:RMP1-14, a specific anti-PD-1 antibody, was injected into spinal trigeminal nucleus caudalis (Sp5C) and measured pain behaviors using von Frey filaments and dolognawmeter. Western blotting and immunofluorescence staining were performed to analyze the expression of PD-1 and tumor necrosis factor alpha (TNFα) in the Sp5C. RESULTS:It was observed that the PD-1 antibody significantly inhibited mechanical hypersensitivity and functional allodynia in our oral cancer pain mouse model. Moreover, we found that TNFα was highly upregulated in the Sp5C following the induction of oral cancer pain and that intra-Sp5C injection of the PD-1 antibody diminished the upregulation of TNFα. It was found that genetic deletion of TNFα or its receptor antagonism synergized the analgesic effect of PD-1 antibody on oral cancer pain. CONCLUSION/CONCLUSIONS:Our results suggest that PD-1 in the Sp5C contributes to oral cancer pain by altering TNFα signaling in the trigeminal nociceptive system, and PD-1 could be targeted to develop a novel approach for oral cancer pain management.

INTRODUCTION/UNASSIGNED:Patients with oral cancer often experience intense functional pain due to mechanical stimulation at the cancer site. The role of mechanosensitive ion channels in oral cancer pain, such as TRPV4, is not fully understood. OBJECTIVES/UNASSIGNED:Our objective was to investigate the role of Schwann cell TRPV4 in oral cancer pain. METHODS/UNASSIGNED:imaging, and patch-clamp electrophysiology. The effect of TRPV4 activation on Schwann cell responses to mechanical stimulation was evaluated using a piezo stimulator. Conditioned media (CM) from TRPV4-activated Schwann cells were injected into the mouse paw to evaluate the contribution of TRPV4 in Schwann cells to mechanical hypersensitivity. RESULTS/UNASSIGNED:responses and whole-cell membrane currents in human Schwann cells. Mechanoactivated currents in human Schwann cells were inhibited by the TRPV4 antagonist HC-067047. Schwann cell CM induced mechanical hypersensitivity in mice, which was blocked by pre-treatment with HC-067047. CONCLUSION/UNASSIGNED:TRPV4 activation plays a role in mediating mechanically induced pain of oral cancer.

BACKGROUND/UNASSIGNED:Essential tremor (ET) is characterized by often disabling action tremors. No pharmacological agent has been developed specifically for symptomatic treatment. Anecdotal reports describe tremor improvement with cannabis, but no evidence exists to support these claims. We conducted a phase Ib/II double-blind, placebo-controlled, crossover pilot trial in participants with ET to investigate tolerability, safety, and efficacy of Tilray TN-CT120 LM, an oral pharmaceutical-grade formulation containing tetrahydrocannabinol (THC) 5 mg and cannabidiol (CBD) 100 mg. Our objectives were to determine if short-term THC/CBD exposure improved tremor amplitude and was tolerated. METHODS/UNASSIGNED:Participants with ET were randomized (1:1) to receive either TN-CT120 LM or placebo. Dose titration, driven by tolerability, was attempted every 2-3 days to three capsules daily maximum. Participants remained on the highest tolerated dose for two weeks before returning to complete assessments. After completing the first arm, participants titrated off the agent, underwent a three-week washout, and then returned for the same procedures with the alternate compound. The primary endpoint was tremor amplitude change from baseline using digital spiral assessment. Secondary endpoints explored safety and tolerability. RESULTS/UNASSIGNED:Among thirteen participants screened, seven were eligible and enrolled. Five completed all visits; one withdrew following a serious adverse event, and another did not tolerate the lowest dose. Intent-to-treat analyses performed for six participants did not reveal significant effects on primary or secondary endpoints. CONCLUSIONS/UNASSIGNED:This pilot trial did not detect any signals of efficacy of THC/CBD in ET. Although preliminary due to the small sample size, our data do not support anecdotal reports of cannabinoid effectiveness for ET. HIGHLIGHTS/UNASSIGNED:This double-blind, randomized, placebo-controlled efficacy and tolerability pilot trial did not detect any signals of efficacy of oral cannabidiol and tetrahydrocannabinol in reducing essential tremor amplitude using either digital outcome measures or clinical rating scales. The oral cannabinoids were well-tolerated by most (five out of seven) participants.

The mammalian brain orchestrates goal-directed behavior through complex interactions between multiple memory systems, with the striatum and hippocampus playing pivotal interrelated roles. A central open question is the extent to which distinct memory signals from these systems drive learning to achieve desired goals and, once those are learned, maintain performance. Here, we used an MRI-compatible platform to obtain whole-brain functional imaging of head-fixed mice as they learn to perform a lick go/no-go odor discrimination task from the naïve state to task proficiency. Behaving mouse functional MRI (fMRI) acquired over a period of several days allowed us to characterize distributed activity as the animals learned the task, demonstrating differential involvement of the striatal and hippocampal memory systems accounting for correct and incorrect task responses. A consideration of the contribution of striatal sub-regions revealed that the responses of the dorsal striatum were correlated with improvement in reaction time, while responses in the ventral striatum were correlated with learning the task and maintaining task performance. In contrast, the dorsal hippocampus showed depressed responses to correct licks to the target odor (hits) and increased responses to incorrect licks to the non-target odor (false alarms). False alarms that were correlated with positive hippocampal responses had longer reaction times and emerged after the mouse learned the task, implicating the hippocampus in driving false memory responses. These results show that behaviorally beneficial actions were correlated with the striatum with a competing involvement of the hippocampus driving erroneous actions, setting the stage to study circuit-based mechanisms of false memory in the mouse.

A long-standing theory for Alzheimer's disease (AD) has been that deterioration of synapses and depressed neuronal activity is a major contributing factor. We review the increasing evidence, in humans and in mouse models, that show that there is often neuronal hyperactivity at early stages rather than decreased activity. We discuss studies in mouse models showing that hyperexcitability can occur long before plaque deposition and memory impairment. In mouse models, a generator of the hyperactivity appears to be the dentate gyrus. We present evidence, based on mouse models, that inhibition of muscarinic cholinergic receptors or medial septal cholinergic neurons can prevent hyperactivity. Therefore, we hypothesize the novel idea that cholinergic neurons are overly active early in the disease, not depressed. In particular we suggest the medial septal cholinergic neurons are overly active and contribute to hyperexcitability. We further hypothesize that the high activity of cholinergic neurons at early ages ultimately leads to their decline in function later in the disease. We review the effects of a prenatal diet that increases choline, the precursor to acetylcholine and modulator of many other functions. In mouse models of AD, maternal choline supplementation (MCS) reduces medial septal cholinergic pathology, amyloid accumulation and hyperexcitability, especially in the dentate gyrus, and improves cognition.

INTRODUCTION/UNASSIGNED:have recently been identified as an ultra-rare cause of pediatric neurodevelopmental disorders (NDDs). However, the neurological and behavioral manifestations, genotype-phenotype correlations, and underlying disease mechanisms remain poorly understood due to the limited number of reported families. METHODS/UNASSIGNED:We describe a cohort of families presenting with microcephaly, global developmental delay, speech impairment, seizures and/or EEG abnormalities, movement disorders and severe behavioral disorders. Clinical assessments and brain imaging studies were conducted over a 10-year follow-up period. Genetic analysis was performed via whole-exome sequencing (WES), and structural modeling was used to investigate the functional impact of the identified variants. RESULTS/UNASSIGNED:-tubulin heterodimer formation, impairing binding stability at this critical interaction site. DISCUSSION/UNASSIGNED:-tubulin interactions.

INTRODUCTION/UNASSIGNED:Individuals with Down syndrome (DS) exhibit neurological deficits throughout life including the development of in Alzheimer's disease (AD) pathology and cognitive impairment. At the cellular level, dysregulation in neuronal gene expression is observed in postmortem human brain and mouse models of DS/AD. To date, RNA-sequencing (RNA-seq) analysis of hippocampal neuronal gene expression including the characterization of discrete circuit-based connectivity in DS remains a major knowledge gap. We postulate that spatially characterized hippocampal neurons display unique gene expression patterns due, in part, to dysfunction of the integrity of intrinsic circuitry. METHODS/UNASSIGNED:We combined laser capture microdissection to microisolate individual neuron populations with single population RNA-seq analysis to determine gene expression analysis of CA1 and CA3 pyramidal neurons and dentate gyrus granule cells located in the hippocampus, a region critical for learning, memory, and synaptic activity. RESULTS/UNASSIGNED:The hippocampus exhibits age-dependent neurodegeneration beginning at ~6 months of age in the Ts65Dn mouse model of DS/AD. Each population of excitatory hippocampal neurons exhibited unique gene expression alterations in Ts65Dn mice. Bioinformatic inquiry revealed unique vulnerabilities and differences with mechanistic implications coinciding with onset of degeneration in this model of DS/AD. CONCLUSIONS/UNASSIGNED:These cell-type specific vulnerabilities may underlie degenerative endophenotypes suggesting precision medicine targeting of individual populations of neurons for rational therapeutic development.

BACKGROUND:Hemodialysis is a water-intense procedure, needing large quantities of water for preparation of small volumes of dialyzate. The resulting large volumes of reject water are usually discarded. With the rising water crisis both in the USA and the world, it is essential to understand water utilization and identify ways to minimize its utilization and maximize the use of the reject water. SUMMARY/CONCLUSIONS:Unfortunately, water from the city sources cannot be used to produce dialyzate unless it undergoes further purification. This results in a large amount of reject water, which can be from 50 to 70% of total water use, resulting in an enormous waste of resources. A review of solutions for water sustainability is broadly classified into solutions that decrease water utilization and solutions for increased reject water utilization. Those that are aimed at decreasing water utilization were mainly based in innovations in technology - examples are NxStage PureFlow™SL, Aquaboss by Braun and AquaBPlus by Fresenius, and those that focused on increased reuse of RO reject water rely on data that it can be safely utilized for various purposes such as irrigation and flushing toilets. These strategies can be cost-effective. Although the need for sustainability has been recognized, there needs to be further awareness and participation among nephrologists to further this cause. In addition, there need to be policies put forward by the government that could encourage sustainability. KEY MESSAGES/CONCLUSIONS:Hemodialysis continues to heavily tax the environment. Although the need for sustainability has been recognized, there still remains a lot of work that needs to be done. Further buy-in is needed from all participating entities - nephrologists, dialysis manufacturers and organizations, and the government in order to safeguard our limited resources.

The posterior "tail" region of the striatum receives dense innervation from sensory brain regions and is important for behaviors that require sensorimotor integration. The output neurons of the striatum, D1 and D2 striatal projection neurons (SPNs), which make up the direct and indirect pathways, are thought to play distinct functional roles, although it remains unclear if these neurons show cell-type-specific differences in their response to sensory stimuli. Here, we examine the strength of synaptic inputs onto D1 and D2 SPNs following the stimulation of upstream auditory pathways. We report that auditory-evoked depolarizations onto D1 SPN responses are stronger and faster. This is due to differences in feedforward inhibition, with fast-spiking interneurons forming stronger synapses onto D2 SPNs. Our results support a model in which differences in feedforward inhibition enable the preferential recruitment of D1 SPNs by auditory stimuli, positioning the direct pathway to initiate sound-driven actions.