Publications by authors named "Lindsay H Burns"

Simufilam is a novel oral drug candidate in Phase 3 clinical trials for Alzheimer's disease (AD) dementia. This small molecule binds an altered form of filamin A (FLNA) that occurs in AD. This drug action disrupts FLNA's aberrant linkage to the α7 nicotinic acetylcholine receptor (α7nAChR), thereby blocking soluble amyloid beta (Aβ)'s signaling via α7nAChR that hyperphosphorylates tau.

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Implicated in both aging and Alzheimer's disease (AD), mammalian target of rapamycin (mTOR) is overactive in AD brain and lymphocytes. Stimulated by growth factors such as insulin, mTOR monitors cell health and nutrient needs. A small molecule oral drug candidate for AD, simufilam targets an altered conformation of the scaffolding protein filamin A (FLNA) found in AD brain and lymphocytes that induces aberrant FLNA interactions leading to AD neuropathology.

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The decades-old cholinergic hypothesis of Alzheimer's disease (AD) led to clinical testing and FDA approval of acetylcholinesterase inhibitor drugs. Subsequently, the α7 nicotinic acetylcholine receptor (α7nAChR) was proposed as a new drug target for enhancing cholinergic neurotransmission. Nearly simultaneously, soluble amyloid β (Aβ ) was shown to bind α7nAChR with picomolar affinity to activate kinases that hyperphosphorylate tau, the precursor to tau-containing tangles.

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Epilepsy treatments for patients with mechanistic target of rapamycin (mTOR) disorders, such as tuberous sclerosis complex (TSC) or focal cortical dysplasia type II (FCDII), are urgently needed. In these patients, the presence of focal cortical malformations is associated with the occurrence of lifelong epilepsy, leading to severe neurological comorbidities. Here, we show that the expression of the actin cross-linking protein filamin A (FLNA) is increased in resected cortical tissue that is responsible for seizures in patients with FCDII and in mice modeling TSC and FCDII with mutations in phosphoinositide 3-kinase (PI3K)-ras homolog enriched in brain (Rheb) pathway genes.

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Objective: This study examined the nasal abuse deterrence of REMOXY ER, a novel high-viscosity extended-release oxycodone formulation.

Design: An Institutional Review Board-approved, single-center, randomized, double-blind, placebo, and active-controlled, four-way crossover study of intranasal REMOXY ER gel, manipulated or intact, and ground oxycodone immediate-release (IR). An open label extension examined pharmacokinetics of OxyContin® ER in the first 20 subjects.

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Objective: These in vitro studies compared abuse-deterrent properties of REMOXY ER (extended-release oxycodone), a novel, high-viscosity gel formulation, versus the two currently marketed ER oxycodone formulations.

Methods: Tampering methods were tailored to each product to maximize oxycodone release with the least complexity, time, and effort, based on the physical/chemical properties of each formulation. Oral abuse was simulated by extracting oxycodone from each manipulated formulation in Common Ingestible Liquids and in Advanced Solvents (not ingestible and requiring additional separation).

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We show that amyloid-β (Aβ) triggers a conformational change in the scaffolding protein filamin A (FLNA) to induce FLNA associations with α7-nicotinic acetylcholine receptor (α7nAChR) and toll-like receptor 4 (TLR4). These aberrant associations respectively enable Aβ's toxic signaling via α7nAChR to hyperphosphorylate tau protein, and TLR4 activation to release inflammatory cytokines. PTI-125 is a small molecule that preferentially binds altered FLNA and restores its native conformation, restoring receptor and synaptic activities and reducing its α7nAChR/TLR4 associations and downstream pathologies.

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Alzheimer's disease (AD) is a neurodegenerative disease with proteopathy characterized by abnormalities in amyloid beta (Aβ) and tau proteins. Defective amyloid and tau propagate and aggregate, leading to eventual amyloid plaques and neurofibrillary tangles. New data show that a third proteopathy, an altered conformation of the scaffolding protein filamin A (FLNA), is critically linked to the amyloid and tau pathologies in AD.

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PTI-125 is a novel compound demonstrating a promising new approach to treating Alzheimer's disease (AD), characterized by neurodegeneration and amyloid plaque and neurofibrillary pathologies. We show that the toxic signaling of amyloid-β(42) (Aβ(42)) by the α7-nicotinic acetylcholine receptor (α7nAChR), which results in tau phosphorylation and formation of neurofibrillary tangles, requires the recruitment of the scaffolding protein filamin A (FLNA). By binding FLNA with high affinity, PTI-125 prevents Aβ(42)'s toxic cascade, decreasing phospho-tau and Aβ aggregates and reducing the dysfunction of α7nAChRs, NMDARs, and insulin receptors.

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Binding a critical pentapeptide region on the scaffolding protein filamin A regulates signaling of mu opioid receptors (MORs) so that their activation should not result in the opioid tolerance, dependence and addiction associated with current opioid painkillers. Additionally, we show that compounds that bind this site on filamin A reduce release of inflammatory cytokines. PTI-609 is a new chemical entity that binds filamin A with picomolar affinity and also activates opioid receptors via a novel binding domain.

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Chronic morphine causes the mu opioid receptor (MOR) to switch its coupling from Gi/o to Gs, resulting in excitatory signaling via both Galphas and its Gbetagamma dimer. Ultra-low-dose naloxone (NLX) prevents this switch and attenuates opioid tolerance and dependence. This protective effect is mediated via a high-affinity interaction of NLX to a pentapeptide region in c-terminal filamin A (FLNA), a scaffolding protein interacting with MOR.

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Unlabelled: Both peripheral nerve injury and chronic opioid treatment can result in hyperalgesia associated with enhanced excitatory neurotransmission at the level of the spinal cord. Chronic opioid administration leads to a shift in mu-opioid receptor (MOR)-G protein coupling from G(i/o) to G(s) that can be prevented by cotreatment with an ultra-low-dose opioid antagonist. In this study, using lumbar spinal cord tissue from rats with L(5)/L(6) spinal nerve ligation (SNL), we demonstrated that SNL injury induces MOR linkage to G(s) in the damaged (ipsilateral) spinal dorsal horn.

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Ultra-low-dose opioid antagonists enhance opioid analgesia and reduce analgesic tolerance and dependence by preventing a G protein coupling switch (Gi/o to Gs) by the mu opioid receptor (MOR), although the binding site of such ultra-low-dose opioid antagonists was previously unknown. Here we show that with approximately 200-fold higher affinity than for the mu opioid receptor, naloxone binds a pentapeptide segment of the scaffolding protein filamin A, known to interact with the mu opioid receptor, to disrupt its chronic opioid-induced Gs coupling. Naloxone binding to filamin A is demonstrated by the absence of [(3)H]-and FITC-naloxone binding in the melanoma M2 cell line that does not contain filamin or MOR, contrasting with strong [(3)H]naloxone binding to its filamin A-transfected subclone A7 or to immunopurified filamin A.

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Unlabelled: Physical dependence or withdrawal is an expected effect of prolonged opioid therapy. Oxytrex (oxycodone + ultralow-dose naltrexone) is an investigational drug shown here to minimize physical dependence while providing strong analgesia with twice-daily dosing. In this 719-patient, double-blind, placebo- and active-controlled Phase III clinical trial in chronic low back pain, patients were randomized to receive placebo, oxycodone qid, or oxytrex qid or bid.

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We previously demonstrated that chronic morphine induces a change in G protein coupling by the mu opioid receptor (MOR) from Gi/o to Gs, concurrent with the instatement of an interaction between Gbetagamma and adenylyl cyclase types II and IV. These two signaling changes confer excitatory effects on the cell in place of the typical inhibition by opioids and are associated with morphine tolerance and dependence. Both signaling changes and these behavioral manifestations of chronic morphine are attenuated by cotreatment with ultra-low-dose naloxone.

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Ultra-low-dose opioid antagonists have been shown to enhance opioid analgesia and alleviate opioid tolerance and dependence. Our present studies in male Sprague-Dawley rats assessed the abuse potential of oxycodone+ultra-low-dose naltrexone (NTX) versus oxycodone alone. The lowest NTX dose (1 pg/kg/infusion), but not slightly higher doses (10 and 100 pg/kg/infusion), enhanced oxycodone (0.

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Rationale: Ultra-low-dose opioid antagonists enhance opiate analgesia and attenuate tolerance and withdrawal.

Objectives: To determine whether ultra-low-dose naltrexone (NTX) coadministration alters the rewarding effects of opiates or the aversive effects of opiate withdrawal.

Methods: We used the conditioned place preference (CPP) and conditioned place aversion (CPA) paradigms to assess whether ultra-low-dose NTX alters the acute rewarding effects of oxycodone or morphine, or the aversive aspect of withdrawal from either drug.

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Unlabelled: Oxytrex is a novel drug that combines oxycodone with ultralow-dose naltrexone, an opioid antagonist. Ultralow-dose opioid antagonists have been demonstrated to enhance and prolong opiate analgesia and alleviate opioid tolerance and withdrawal in rodents. This 3-week, Phase II clinical trial assessed safety and analgesic efficacy of Oxytrex in patients with moderate to severe pain from osteoarthritis.

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