Search

The acid-sensing ion channel 1a (ASIC1a) is a trimeric ligand-gated ion channel. Its activation by protons results in influx of Na+ and, to a lesser extent, Ca2+ before the channel rapidly desensitizes. ASIC1a-mediated currents contribute to normal brain function, including long term potentiation, which is important for learning and memory. However, elevated activity of ASIC1a has been directly implicated in the pathogenesis of numerous disorders, such as ischemic brain injury, cancer, pain and Alzheimer's disease. Recent evidence suggests that during such pathological conditions, association with protein interaction partners can affect ASIC1a activity, thereby contributing to neuronal damage and cell death. Consequently, there is an increasing interest in understanding the regulation of ASIC1a by protein-interaction partners, which remain largely enigmatic. Here, we have used a combination of mass spectrometry, biochemistry and electrophysiology to identify a family of transporters that directly interacts with ASIC1a and regulates its function. Depending on the specific transporter isoform present in the channel-transporter complex, the activation of ASIC1a is either prolonged and potentiated or decreased. We anticipate this work to offer promising starting points for therapeutic targeting of ASIC1a-containing macromolecular complexes in various diseases.

The present disclosure relates to compounds which bind Ca2+/calmodulin dependent protein kinase II. It also relates to such compounds for use in the treatment of CNS disorders with sleep disturbances and acute brain injury.

Narcolepsy type 1 (NT1) is a neurological disorder caused by disruption of hypocretin (HCRT; or orexin) neurotransmission leading to fragmented sleep/wake states, excessive daytime sleepiness, and cataplexy (abrupt muscle atonia during wakefulness). Electroencephalography and electromyography (EEG/EMG) monitoring is the gold standard to assess NT1 phenotypical features in both humans and mice. Here, we evaluated the digital ventilated home-cage (DVC®) activity system as an alternative to detect NT1 features in two NT1 mouse models: the genetic HCRT-knockout (-KO) model, and the inducible HCRT neuron-ablation hcrt-tTA;TetO-DTA (DTA) model, including both sexes. NT1 mice exhibited an altered dark phase activity profile and increased state transitions, compared to the wild-type (WT) phenotype. An inability to sustain activity periods >40 min represented a robust activity-based NT1 biomarker. These features were observable within the first weeks of HCRT neuron degeneration in DTA mice. We also created a nest-identification algorithm to differentiate between inactivity and activity, inside and outside the nest as a sleep and wake proxy, respectively, showing significant correlations with EEG/EMG-assessed sleep/wake behavior. Lastly, we tested the sensitivity of the activity system to detect behavioral changes in response to interventions such as repeated saline injection and chocolate. Surprisingly, daily consecutive saline injections significantly reduced activity and increased nest time of HCRT-WT mice. Chocolate increased total activity in all mice, and increased the frequency of short out-of-nest inactivity episodes in HCRT-KO mice. We conclude that the DVC® system provides a useful tool for non-invasive monitoring of NT1 phenotypical features, and has the potential to monitor drug effects in NT1 mice., Narcolepsy type 1 (NT1) is a neurological disorder caused by disruption of hypocretin (HCRT; or orexin) neurotransmission leading to fragmented sleep/wake states, excessive daytime sleepiness, and cataplexy (abrupt muscle atonia during wakefulness). Electroencephalography and electromyography (EEG/EMG) monitoring is the gold standard to assess NT1 phenotypical features in both humans and mice. Here, we evaluated the digital ventilated home-cage (DVC®) activity system as an alternative to detect NT1 features in two NT1 mouse models: the genetic HCRT-knockout (-KO) model, and the inducible HCRT neuron-ablation hcrt-tTA;TetO-DTA (DTA) model, including both sexes. NT1 mice exhibited an altered dark phase activity profile and increased state transitions, compared to the wild-type (WT) phenotype. An inability to sustain activity periods >40 min represented a robust activity-based NT1 biomarker. These features were observable within the first weeks of HCRT neuron degeneration in DTA mice. We also created a nest-identification algorithm to differentiate between inactivity and activity, inside and outside the nest as a sleep and wake proxy, respectively, showing significant correlations with EEG/EMG-assessed sleep/wake behavior. Lastly, we tested the sensitivity of the activity system to detect behavioral changes in response to interventions such as repeated saline injection and chocolate. Surprisingly, daily consecutive saline injections significantly reduced activity and increased nest time of HCRT-WT mice. Chocolate increased total activity in all mice, and increased the frequency of short out-of-nest inactivity episodes in HCRT-KO mice. We conclude that the DVC® system provides a useful tool for non-invasive monitoring of NT1 phenotypical features, and has the potential to monitor drug effects in NT1 mice.

Two new structural studies of the GABA transporter subtype GAT1 reveal detailed snapshots of the GABA transport cycle, providing new mechanistic insights and blueprints for rational design of novel leads that target GABAergic systems.

Ca2+/calmodulin-dependent protein kinase II alpha (CaMKII alpha) is a brain-relevant kinase and an emerging drug target for ischemic stroke and neurodegenerative disorders. Despite reported CaMKII alpha inhibitors, their usefulness is limited by low subtype selectivity and brain permeability. (E)-2-(5-Hydroxy-5,7,8,9-tetrahydro-6H-benzo[7]annulen-6-ylidene)acetic acid (NCS-382) is structurally related to the proposed neuromodulator, gamma-hydroxybutyric acid, and is a brain-penetrating high nanomolar-affinity ligand selective for the CaMKII alpha hub domain. Herein, we report the first series of NCS-382 analogs displaying improved affinity and preserved brain permeability. Specifically, we present Ph-HTBA (1i) with enhanced mid-nanomolar affinity for the CaMKII alpha binding site and a marked hub thermal stabilization effect along with a distinct CaMKII alpha Trp403 flip upon binding. Moreover, Ph-HTBA has good cellular permeability and low microsomal clearance and shows brain permeability after systemic administration to mice, signified by a high Kp, uu value (0.85). Altogether, our study highlights Ph-HTBA as a promising candidate for CaMKII alpha-associated pharmacological interventions and future clinical development.

Novel gamma-aminobutyric acid (GABA) analogues 3-5, having a bicyclo[3.1.0]hexene, [4.1.0]heptane, or [4.1.0]heptene backbone, respectively, were designed from the bioactive form analysis of the previous inhibitor 2 with a bicyclo[3.1.0]hexane backbone. Compounds 3-5 and 2 were synthesized from a common 1,7-diene intermediate 6 using ring-closing metathesis (RCM) to construct the key bicyclo backbones. Compounds 3-5 strongly inhibit betaine/GABA transporter 1 (BGT1) uptake, but compound 4 stands out with its selective low micromolar potency.

The anesthetic effect of Alpinia galanga oil (AGO) has been reported. However, knowledge of its pathway in mammals is limited. In the present study, the binding of AGO and its key compounds, methyl eugenol, 1,8-cineole, and 4-allylphenyl acetate, to gamma-aminobutyric acid type A (GABA(A)) receptors in rat cortical membranes, was investigated using a [H-3]muscimol binding assay and an in silico modeling platform. The results showed that only AGO and methyl eugenol displayed a positive modulation at the highest concentrations, whereas 1,8-cineole and 4-allylphenyl acetate were inactive. The result of AGO correlated well to the amount of methyl eugenol in AGO. Computational docking and dynamics simulations into the GABA(A) receptor complex model (PDB: 6X3T) showed the stable structure of the GABA(A) receptor-methyl eugenol complex with the lowest binding energy of -22.16 kcal/mol. This result shows that the anesthetic activity of AGO and methyl eugenol in mammals is associated with GABA(A) receptor modulation. An oil-in-water nanoemulsion containing 20% w/w AGO (NE-AGO) was formulated. NE-AGO showed a significant increase in specific [H-3]muscimol binding, to 179% of the control, with an EC50 of 391 mu g/mL. Intracellular studies show that normal human cells are highly tolerant to AGO and the nanoemulsion, indicating that NE-AGO may be useful for human anesthesia.