Bromwich, M. | bioRxiv Science

bioRxiv2025

Kv1.3 inhibition alleviates neuropathology via neuroinflammatory and resilience pathways in a mouse model of Aβ pathology

Inhibition of voltage-gated potassium channel Kv1.3 is a therapeutic strategy to curb microglia-mediated neuroinflammation in neurodegeneration, although the cellular and signaling mechanisms of disease-modification by Kv1.3 blockers are unclear. In this study, we delineate protective mechanisms of Kv1.3 blockade in a mouse model of Alzheimers disease (AD) pathology using comprehensive transcriptomics and proteomics profiling of brain, corresponding with neuropathological effects of two translationally relevant Kv1.3 blockers, namely small molecule PAP-1 and peptide ShK-223. Following 3 months of treatment, both molecules reduced Ab plaque burden. Single nuclear RNA seq (snRNA seq) of brain nuclei showed that PAP-1 disproportionately impacted oligodendrocytes and microglia and increased crosstalk between neurons and astrocytes with endothelial cells. In contrast, ShK-223 had pronounced effects on glutamatergic neurons and astrocytes. Both blockers increased expression of myelination genes in oligodendrocytes and synaptic genes in neurons. Neuroprotective effects of PAP-1 were further confirmed by bulk brain transcriptomics and proteomics whereby PAP-1 increased levels of synaptic, cognitive resilience and mitochondrial proteins, while decreasing glial and immune pathways including STAT1/3 phosphorylation. Using proximity labeling and co-immunoprecipitation, we found that Kv1.3 interacts with STAT1/3 in microglia. Using microglial cell lines and primary microglia, we discovered a preferential functional coupling between Kv1.3 and type 2 but not type 1 IFN signaling. Brain-level disease modification by Kv1.3 blockade was reflected in the cerebrospinal fluid (CSF) via reduced levels of neurofilament-light (NEFL) and resilience protein RPH3A, both of which are increased in human AD CSF. Together, this study demonstrates functional links between Kv1.3 channels and type 2 IFN signaling and reveals distinct cellular effects of Kv1.3 blockers in AD pathology that correspond with reduced neuropathology and neuroinflammation, augmentation of resilience and neuro-vascular pathways, along with biomarkers of therapeutic effect.

neuroscience↗

bioRxiv2023

Disease-causing Slack potassium channel mutations produce opposite effects on excitability of excitatory and inhibitory neurons

KCNT1 encodes the sodium-activated potassium channel Slack (KCNT1, KNa1.1), an important mediator of neuronal membrane excitability. Gain-of-function (GOF) mutations in humans lead cortical network hyperexcitability and seizures, as well as very severe intellectual disability. Using a mouse model of Slack GOF-associated epilepsy, we found that both excitatory and inhibitory neurons of the cerebral cortex have increased Na+-dependent K+ (KNa) currents and voltage-dependent sodium (NaV) currents. The characteristics of the increased KNa currents were, however, different in the two cell types such that the intrinsic excitability of excitatory neurons was enhanced but that of inhibitory neurons was suppressed. We further showed that the expression of NaV channel subunits, particularly that of NaV1.6, is upregulated and that the length of the axon initial segment (AIS) and of axonal NaV immunostaining is increased in both neuron types. We found that the proximity of the AIS to the soma is shorter in excitatory neurons than in inhibitory neurons of the mutant animals, potentially contributing to the different effects on membrane excitability. Our study on the coordinate regulation of KNa currents and the expression of NaV channels may provide a new avenue for understanding and treating epilepsies and other neurological disorders. In briefIn a genetic mouse model of Na+-activated K+ potassium channel gene Slack-related childhood epilepsy, Wu et al. show that a disease-causing gain-of-function (GOF) mutation R455H in Slack channel causes opposite effects on excitability of cortical excitatory and inhibitory neurons. In contrast to heterologous expression systems, they find that the increase in potassium current substantially alters the expression of sodium channel subunits, resulting in increased lengths of axonal initial segments. HighlightsGOF mutations in Slack potassium channel cause elevated outward K+currents and inward voltage-dependent Na+ (NaV) currents in cortical neurons Slack GOF does not alter the expression of Slack channel but upregulates the expression of NaV channel Slack GOF enhances the excitability of excitatory neurons but suppresses the firing of inhibitory interneurons Slack GOF alters the length of AIS in both excitatory and inhibitory neurons Proximity of AIS to the soma is different between excitatory neuron and inhibitory neuron

neuroscience↗