{ "type": "Document", "metadata": { "doi": "10.7554/eLife.103784", "title": "Impaired excitability of fast-spiking neurons in a novel mouse model of KCNC1 epileptic encephalopathy", "authors": [ "Wengert et al." ] }, "children": [ { "type": "ClaimGraph", "identifier": "wengert-2026-kcnc1-claims", "children": [ { "type": "Claim", "identifier": "a421v-kv31-membrane-trafficking-impaired", "role": "empirical", "children": [ { "type": "Text", "value": "The ratio of membrane to cytosolic Kv3.1 immunofluorescence intensity is significantly reduced in PV-INs from juvenile (P24–33) Kcnc1-A421V/+ mice compared to WT controls (n=48 vs n=49 cells, N=5 vs N=6 mice), indicating that impaired trafficking to the cell surface contributes to the loss of K+ current density." } ], "epistemicStrength": "strong", "relations": [ { "xref": "prediction-kv31-surface-expression-reduced", "relationType": "claimrel:tests" }, { "xref": "prediction-kv31-surface-expression-reduced", "relationType": "cito:confirms" }, { "xref": "hypothesis-a421v-causes-kv31-lof", "relationType": "cito:confirms" }, { "xref": "pv-ins-reduced-k-current-density", "relationType": "cito:supports" }, { "xref": "pv-ins-reduced-k-current-density", "relationType": "cito:extends" } ], "metadata": { "uuid": "ba388b6b-662d-4f09-b481-11f90f7057dc", "concepts": [ "Kv3.1", "membrane trafficking", "immunohistochemistry", "PV interneurons", "subcellular localization" ] } }, { "type": "Claim", "identifier": "a421v-mice-die-before-122d", "role": "empirical", "children": [ { "type": "Text", "value": "All Kcnc1-A421V/+ knock-in mice die before 122 days of age, while wild-type littermates survive significantly longer (Mantel-Cox p<0.001; n=33 mutant, n=46 wild-type)." } ], "epistemicStrength": "strong", "relations": [ { "xref": "prediction-seizures-and-sudep", "relationType": "cito:confirms" }, { "xref": "hypothesis-pv-dysfunction-drives-encephalopathy", "relationType": "cito:confirms" } ], "metadata": { "uuid": "e2edfcd1-ec01-4ec7-ba36-01ab26290d69", "concepts": [ "KCNC1", "A421V", "survival", "mortality", "knock-in mouse" ] } }, { "type": "Claim", "identifier": "a421v-spatial-learning-working-memory-impaired", "role": "empirical", "children": [ { "type": "Text", "value": "Young adult Kcnc1-A421V/+ mice (P35–65) exhibit significantly longer escape latencies during Barnes maze acquisition (most pronounced on day 2) and a significantly reduced percentage of spontaneous alternations in the Y-maze, indicating impairment in both spatial learning and spatial working memory, with long-term memory retention intact." } ], "epistemicStrength": "strong", "relations": [ { "xref": "prediction-cognitive-deficits", "relationType": "claimrel:tests" }, { "xref": "prediction-cognitive-deficits", "relationType": "cito:confirms" }, { "xref": "hypothesis-pv-dysfunction-drives-encephalopathy", "relationType": "cito:confirms" }, { "xref": "inhibitory-dysfunction-progresses-to-adulthood", "relationType": "claimrel:requires" } ], "metadata": { "uuid": "ae5f131c-edc3-4345-96c1-2f43609dbb3e", "concepts": [ "cognitive function", "spatial learning", "working memory", "Barnes maze", "Y-maze", "KCNC1" ] } }, { "type": "Claim", "identifier": "a421v-weight-reduced-milestones-normal", "role": "empirical", "children": [ { "type": "Text", "value": "Kcnc1-A421V/+ mice show significantly reduced body and brain weight relative to WT littermates, but display no detectable abnormalities in gross developmental milestones (fur appearance, eye opening, ear canal opening, incisor eruption, motor benchmarks) assessed at P5–15." } ], "epistemicStrength": "strong", "relations": [ { "xref": "a421v-spatial-learning-working-memory-impaired", "relationType": "cito:disagreesWith" }, { "xref": "a421v-mice-die-before-122d", "relationType": "cito:supports" } ], "metadata": { "uuid": "b7a7c44d-b512-45b8-a790-a1b2c3b216e7", "concepts": [ "body weight", "brain weight", "developmental milestones", "early postnatal development", "KCNC1" ] } }, { "type": "Claim", "identifier": "alt-inhibitory-dysfunction-present-juvenile", "role": "hypothesis", "children": [ { "type": "Text", "value": "Inhibitory dysfunction in Kcnc1-A421V/+ mice is already established at the juvenile stage (P16-21) rather than emerging with age, so the phenotype is developmentally static rather than progressive." } ], "stance": "rejects", "metadata": { "uuid": "8f0f1866-b184-4166-8ed7-97af70a45e88", "concepts": [ "developmental progression", "inhibitory dysfunction", "alternative explanation" ] } }, { "type": "Claim", "identifier": "excitatory-neurons-unaffected-adult", "role": "control", "children": [ { "type": "Text", "value": "Excitatory neurons from adult (P32–42) Kcnc1-A421V/+ mice show no significant differences from WT in AP firing frequency across current injection magnitudes, and show no significant alterations in passive membrane properties or single AP properties (Table 2), with the sole exception of reduced rheobase (*p=0.023) whose functional significance is uncertain." } ], "epistemicStrength": "moderate", "relations": [ { "xref": "prediction-excitatory-neurons-spared", "relationType": "claimrel:tests" }, { "xref": "pv-in-inhibitory-synapse-altered-adult", "relationType": "cito:confirms" }, { "xref": "prediction-excitatory-neurons-spared", "relationType": "cito:confirms" }, { "xref": "excitatory-neurons-unaffected-juvenile", "relationType": "cito:extends" } ], "metadata": { "uuid": "3df55d45-b8a0-42c6-9807-0323c08e8815", "concepts": [ "excitatory neurons", "cell-type selectivity", "adult", "intrinsic excitability", "null result" ] } }, { "type": "Claim", "identifier": "excitatory-neurons-unaffected-juvenile", "role": "control", "children": [ { "type": "Text", "value": "No significant differences in synaptic transmission or intrinsic excitability are observed in excitatory neurons at juvenile stage (P16-21), indicating the Kcnc1-A421V variant selectively impairs inhibitory PV-INs rather than excitatory neurons." } ], "epistemicStrength": "moderate", "relations": [ { "xref": "prediction-excitatory-neurons-spared", "relationType": "claimrel:tests" }, { "xref": "pv-ins-reduced-k-current-density", "relationType": "cito:confirms" }, { "xref": "pv-ins-impaired-maximal-firing", "relationType": "cito:confirms" }, { "xref": "prediction-excitatory-neurons-spared", "relationType": "cito:confirms" } ], "metadata": { "uuid": "52b1301c-8ece-44c1-b25c-53e20013391d", "concepts": [ "excitatory neurons", "cell-type selectivity", "juvenile", "synaptic transmission", "specificity" ] } }, { "type": "Claim", "identifier": "hypothesis-a421v-causes-kv31-lof", "role": "hypothesis", "children": [ { "type": "Text", "value": "The recurrent missense variant KCNC1-p.Ala421Val (A421V) in the Kv3.1 voltage-gated potassium channel causes a loss of channel function via impaired delivery of channel protein to the plasma membrane (a trafficking defect), rather than via altered gating or conductance of channels that do reach the surface. The hypothesis predicts that in heterozygous expression — the genetic configuration of human disease — a measurable reduction in surface Kv3.1 should accompany a reduction in voltage-gated K+ current density, while voltage-dependence of activation and activation kinetics of the remaining current should be preserved. The trafficking-deficit account is favoured over a pure gating account because Kv3.1 channels are obligate tetramers: a dominant- negative trafficking effect of the mutant subunit on heteromeric tetramers can parsimoniously explain the larger-than-50% current loss observed in heterozygous cells." } ], "panel": [ "hypothesis" ], "relations": [ { "xref": "prediction-pv-in-k-current-reduced", "relationType": "claimrel:entails" }, { "xref": "prediction-kv31-surface-expression-reduced", "relationType": "claimrel:entails" } ], "metadata": { "uuid": "6b95034b-bded-485f-b080-2e7db1856e34", "concepts": [ "KCNC1", "A421V", "Kv3.1", "loss-of-function", "membrane trafficking", "dominant-negative" ], "displayClaim": "KCNC1-A421V is a Kv3.1 loss-of-function variant whose primary lesion is impaired surface trafficking of the channel — not altered gating or conductance.", "shortClaim": "KCNC1-A421V is a Kv3.1 loss-of-function variant driven by impaired surface trafficking." } }, { "type": "Claim", "identifier": "hypothesis-pv-dysfunction-drives-encephalopathy", "role": "hypothesis", "children": [ { "type": "Text", "value": "Cell-autonomous loss of Kv3.1 function in PV-INs is sufficient to drive the network-level developmental and epileptic encephalopathy phenotype of KCNC1 disease. Specifically, the impaired fast-spiking capacity of PV-INs reduces effective perisomatic inhibition of cortical excitatory neurons, causing increased excitatory network activity, hypersynchronous discharges, and clinically apparent seizures with premature lethality (SUDEP), as well as cognitive deficits attributable to disrupted PV-IN-dependent learning and plasticity. The hypothesis predicts that the inhibitory failure should manifest in vivo as elevated excitatory firing during low-arousal states, paroxysmal hypersynchronous discharges in mutants only, spontaneous convulsive seizures, and SUDEP — recapitulating the human KCNC1 DEE phenotype. It further predicts that synaptic-level inhibitory dysfunction may emerge progressively, if PV-IN spike output is impaired before terminal release machinery accumulates compensatory or pathological adaptations." } ], "panel": [ "hypothesis" ], "relations": [ { "xref": "prediction-network-hyperexcitability-in-vivo", "relationType": "claimrel:entails" }, { "xref": "prediction-seizures-and-sudep", "relationType": "claimrel:entails" }, { "xref": "prediction-cognitive-deficits", "relationType": "claimrel:entails" }, { "xref": "prediction-progressive-synaptic-failure", "relationType": "claimrel:entails" } ], "metadata": { "uuid": "61e1a6da-52f8-426d-83bd-dd6f4cfa96fb", "concepts": [ "epileptic encephalopathy", "PV interneurons", "perisomatic inhibition", "network excitability", "SUDEP", "cognitive deficit" ], "displayClaim": "Cell-autonomous Kv3.1 LOF in PV-INs is sufficient to drive the KCNC1 DEE phenotype: reduced inhibition → network hyperexcitability → seizures, SUDEP, and cognitive deficits.", "shortClaim": "Cell-autonomous Kv3.1 loss in PV interneurons is sufficient to cause the KCNC1 DEE phenotype." } }, { "type": "Claim", "identifier": "hypothesis-pv-in-selective-vulnerability", "role": "hypothesis", "children": [ { "type": "Text", "value": "Because Kv3.1 is strongly and selectively expressed in fast-spiking neurons that rely on rapid action-potential repolarization to sustain high firing rates, haploinsufficient or dominant-negative loss of Kv3.1 should produce a cell-type- specific impairment that targets parvalbumin-positive (PV+) GABAergic interneurons while leaving excitatory neurons (which do not express Kv3.1 at functionally relevant levels) intact. Within the population of fast-spiking neurons, the magnitude of impairment should grade with the relative dependence on Kv3.1 versus the partially redundant Kv3.2 subunit: cells with predominant Kv3.1 expression and minimal Kv3.2 compensation (cortical superficial PV-INs, reticular thalamic nucleus PV-INs) should show the largest deficit, while cells with greater Kv3.2 expression (deep-layer cortical PV-INs) should show milder phenotypes." } ], "panel": [ "hypothesis" ], "relations": [ { "xref": "prediction-pv-in-firing-impaired", "relationType": "claimrel:entails" }, { "xref": "prediction-excitatory-neurons-spared", "relationType": "claimrel:entails" }, { "xref": "prediction-impairment-grades-with-kv31-dependence", "relationType": "claimrel:entails" } ], "metadata": { "uuid": "9b4806b8-4b5f-44cd-a04b-a2acc45cffb3", "concepts": [ "PV interneurons", "cell-type specificity", "Kv3.1", "Kv3.2", "fast-spiking", "selective vulnerability" ], "displayClaim": "Kv3.1 loss-of-function should selectively impair fast-spiking PV-INs that depend on Kv3.1 for high-frequency firing, sparing excitatory neurons; impairment magnitude should grade with the Kv3.1:Kv3.2 expression ratio across cell populations.", "shortClaim": "Kv3.1 loss selectively impairs fast-spiking PV-INs, sparing excitatory neurons." } }, { "type": "Claim", "identifier": "in-vivo-hypersynchronous-discharges-mutant-only", "role": "empirical", "children": [ { "type": "Text", "value": "Paroxysmal hypersynchronous discharges in the neuropil calcium signal are observed in 7 of 7 Kcnc1-A421V/+ mice examined in vivo (>P50) by two-photon GCaMP imaging, but never in WT mice (N=5), each discharge coinciding with a brief diffuse twitch of the facial musculature and bilateral limbs consistent with myoclonic seizures." } ], "epistemicStrength": "strong", "relations": [ { "xref": "prediction-network-hyperexcitability-in-vivo", "relationType": "claimrel:tests" }, { "xref": "prediction-network-hyperexcitability-in-vivo", "relationType": "cito:confirms" }, { "xref": "hypothesis-pv-dysfunction-drives-encephalopathy", "relationType": "cito:confirms" }, { "xref": "a421v-mice-die-before-122d", "relationType": "cito:supports" } ], "metadata": { "uuid": "2d6bb516-6c05-4a2f-bb64-9e9142bbf326", "concepts": [ "hypersynchronous discharge", "two-photon calcium imaging", "in vivo", "neuropil", "myoclonic seizures", "KCNC1" ] } }, { "type": "Claim", "identifier": "in-vivo-pv-minus-transient-frequency-increased", "role": "empirical", "children": [ { "type": "Text", "value": "During quiet rest, PV– (excitatory) cells in Kcnc1-A421V/+ mice show significantly increased calcium transient frequency (mean 1.63 vs 1.17 transients/min in WT; n=1041 vs 885 cells), while PV+ cell transient frequency is not significantly changed but PV+ transient amplitude is reduced (mean 0.40 vs 0.48 dF/F0), consistent with decreased perisomatic inhibition in vivo." } ], "epistemicStrength": "moderate", "relations": [ { "xref": "prediction-network-hyperexcitability-in-vivo", "relationType": "claimrel:tests" }, { "xref": "prediction-network-hyperexcitability-in-vivo", "relationType": "cito:confirms" }, { "xref": "hypothesis-pv-dysfunction-drives-encephalopathy", "relationType": "cito:confirms" }, { "xref": "pv-ins-impaired-maximal-firing", "relationType": "cito:supports" }, { "xref": "in-vivo-hypersynchronous-discharges-mutant-only", "relationType": "cito:extends" } ], "metadata": { "uuid": "890a5223-4eb7-4dd0-a112-42e195398da1", "concepts": [ "in vivo calcium imaging", "PV interneurons", "excitatory neurons", "calcium transients", "network excitability", "perisomatic inhibition" ] } }, { "type": "Claim", "identifier": "inhibitory-dysfunction-progresses-to-adulthood", "role": "synthesis", "children": [ { "type": "Text", "value": "Inhibitory neurotransmission shows no significant alterations at juvenile stage (P16-21) but exhibits altered function by young adulthood (P32-42), indicating progressive deterioration of inhibitory circuit function in Kcnc1-A421V/+ mice." } ], "epistemicStrength": "moderate", "relations": [ { "xref": "pv-in-inhibitory-synapse-intact-juvenile", "relationType": "claimrel:interprets" }, { "xref": "pv-in-inhibitory-synapse-altered-adult", "relationType": "claimrel:interprets" }, { "xref": "prediction-progressive-synaptic-failure", "relationType": "cito:confirms" } ], "metadata": { "uuid": "a2af2706-be34-44a7-b65b-6a11ae98c2a8", "concepts": [ "progressive deterioration", "inhibitory neurotransmission", "juvenile", "young adult", "developmental progression" ], "shortClaim": "Inhibitory dysfunction in Kcnc1-A421V/+ mice emerges progressively by young adulthood." } }, { "type": "Claim", "identifier": "kcnc1-wet-lab-primary-claims", "role": "methodological", "children": [ { "type": "Text", "value": "All primary claims about Kcnc1-A421V/+ phenotype (survival, potassium current, firing frequency, inhibitory dysfunction) require the proprietary knock-in mouse model and wet-lab measurements; these claims cannot be reproduced from deposited data alone — they require the mouse colony and associated equipment (patch-clamp, 2P calcium imaging)." } ], "epistemicStrength": "strong", "relations": [ { "xref": "pv-ins-reduced-k-current-density", "relationType": "cito:usesMethodIn" }, { "xref": "pv-ins-impaired-maximal-firing", "relationType": "cito:usesMethodIn" }, { "xref": "pv-in-ap-waveform-altered-downstroke-apd50", "relationType": "cito:usesMethodIn" }, { "xref": "a421v-kv31-membrane-trafficking-impaired", "relationType": "cito:usesMethodIn" }, { "xref": "layer-v-pv-ins-subtle-impairment", "relationType": "cito:usesMethodIn" }, { "xref": "rtn-neurons-impaired-excitability", "relationType": "cito:usesMethodIn" }, { "xref": "excitatory-neurons-unaffected-juvenile", "relationType": "cito:usesMethodIn" }, { "xref": "excitatory-neurons-unaffected-adult", "relationType": "cito:usesMethodIn" }, { "xref": "pv-in-inhibitory-synapse-intact-juvenile", "relationType": "cito:usesMethodIn" }, { "xref": "pv-in-inhibitory-synapse-altered-adult", "relationType": "cito:usesMethodIn" }, { "xref": "in-vivo-hypersynchronous-discharges-mutant-only", "relationType": "cito:usesMethodIn" }, { "xref": "in-vivo-pv-minus-transient-frequency-increased", "relationType": "cito:usesMethodIn" }, { "xref": "spontaneous-seizures-and-sudep-kcnc1", "relationType": "cito:usesMethodIn" }, { "xref": "a421v-mice-die-before-122d", "relationType": "cito:usesMethodIn" }, { "xref": "a421v-spatial-learning-working-memory-impaired", "relationType": "cito:usesMethodIn" }, { "xref": "a421v-weight-reduced-milestones-normal", "relationType": "cito:usesMethodIn" } ], "metadata": { "uuid": "e61d53f9-f821-48eb-8392-f02acef3d444", "concepts": [ "wet lab", "knock-in mouse", "reproduction barrier", "primary claims" ] } }, { "type": "Claim", "identifier": "layer-v-pv-ins-subtle-impairment", "role": "empirical", "children": [ { "type": "Text", "value": "Layer V neocortical PV-INs from juvenile (P16–21) Kcnc1-A421V/+ mice show more subtle abnormalities than layer II-IV PV-INs: AP frequency reduction is confined to the largest current injection magnitudes (***p<0.001 for genotype × current injection interaction), consistent with the higher relative expression of Kv3.2 vs Kv3.1 in deeper cortical layers." } ], "epistemicStrength": "strong", "relations": [ { "xref": "pv-ins-impaired-maximal-firing", "relationType": "cito:disagreesWith" }, { "xref": "prediction-impairment-grades-with-kv31-dependence", "relationType": "claimrel:tests" }, { "xref": "prediction-impairment-grades-with-kv31-dependence", "relationType": "cito:confirms" }, { "xref": "hypothesis-pv-in-selective-vulnerability", "relationType": "cito:confirms" }, { "xref": "pv-ins-impaired-maximal-firing", "relationType": "cito:extends" }, { "xref": "inhibitory-dysfunction-progresses-to-adulthood", "relationType": "cito:supports" } ], "metadata": { "uuid": "d6e81203-d9f1-4344-97d0-48ec7b6afe39", "concepts": [ "layer V", "PV interneurons", "cell-type specificity", "Kv3.1 vs Kv3.2", "laminar differences" ] } }, { "type": "Claim", "identifier": "prediction-cognitive-deficits", "role": "prediction", "children": [ { "type": "Text", "value": "If PV-IN dysfunction in Kcnc1-A421V/+ mice impairs the inhibitory circuits underlying cortical learning and plasticity, then mutant mice should show measurable cognitive deficits in tasks that depend on PV-IN-supported processes — specifically spatial learning (Barnes maze, with deficits most evident during the acquisition phase) and spatial working memory (Y-maze spontaneous alternation). The deficit should be specific (not attributable to locomotor or exploratory confounds) and should recapitulate the moderate-to-severe developmental delay seen in human KCNC1 DEE patients. Long-term memory retention (Barnes maze probe trial) may or may not be intact, depending on whether the deficit is in learning rate or memory storage." } ], "panel": [ "prediction" ], "relations": [ { "xref": "hypothesis-pv-dysfunction-drives-encephalopathy", "relationType": "cito:citesAsSourceDocument" } ], "metadata": { "uuid": "3ea91341-e08d-4f0b-86fc-604dd4b1ebd6", "concepts": [ "prediction", "cognitive deficit", "spatial learning", "working memory", "Barnes maze", "Y-maze" ], "displayClaim": "Kcnc1-A421V/+ mice should show specific cognitive deficits in spatial learning (Barnes maze acquisition) and working memory (Y-maze) without locomotor confounds." } }, { "type": "Claim", "identifier": "prediction-excitatory-neurons-spared", "role": "prediction", "children": [ { "type": "Text", "value": "If the A421V variant exerts its cellular effect specifically through Kv3.1 — which is not expressed at functionally relevant levels in cortical excitatory neurons — then excitatory neurons in Kcnc1-A421V/+ mice should be functionally spared: voltage-gated K+ current density, intrinsic excitability (firing-frequency vs current-injection relationship), AP waveform parameters, and synaptic transmission should not differ significantly from WT. The null result must hold at both juvenile and adult stages to exclude both cell-autonomous and secondary network effects on excitatory cells. This is the negative-control half of the cell-type specificity test." } ], "panel": [ "prediction" ], "relations": [ { "xref": "hypothesis-pv-in-selective-vulnerability", "relationType": "cito:citesAsSourceDocument" } ], "metadata": { "uuid": "e216fbcf-8d86-4470-9206-c27a0b4a04f7", "concepts": [ "prediction", "excitatory neurons", "cell-type specificity", "null result", "negative control" ], "displayClaim": "Excitatory neurons should show no significant impairment of K+ current, firing, AP waveform, or synaptic transmission at either juvenile or adult stages." } }, { "type": "Claim", "identifier": "prediction-impairment-grades-with-kv31-dependence", "role": "prediction", "children": [ { "type": "Text", "value": "If the impairment is specifically Kv3.1-mediated, then within the population of fast-spiking PV-INs the magnitude of phenotype should grade with the relative expression of Kv3.1 versus the partially redundant Kv3.2 subunit. Specifically, superficial neocortical PV-INs (layer II–IV; predominantly Kv3.1) should show the largest deficit; deep neocortical PV-INs (layer V; greater Kv3.2 expression) should show milder deficits confined to the highest current injections; and reticular thalamic nucleus (RTN) PV-INs (predominantly Kv3.1 and Kv3.3, no Kv3.2 compensation) should also show impairment but with a phenotype shaped by their distinctive rebound firing physiology. This graded prediction is a stronger discriminator of mechanism than a single-population test, because alternative mechanisms (generic PV vulnerability, generic neocortical defect) cannot easily produce a Kv3.1:Kv3.2- ratio-aligned gradient." } ], "panel": [ "prediction" ], "relations": [ { "xref": "hypothesis-pv-in-selective-vulnerability", "relationType": "cito:citesAsSourceDocument" } ], "metadata": { "uuid": "757e5bfc-b456-48a1-b49a-e662e2e69a30", "concepts": [ "prediction", "laminar gradient", "Kv3.1 vs Kv3.2", "reticular thalamic nucleus", "mechanistic specificity" ], "displayClaim": "Phenotype magnitude across PV-IN populations should grade with Kv3.1 dependence: superficial cortical (largest), layer V (mildest), RTN (intermediate, distinctive rebound-firing pattern)." } }, { "type": "Claim", "identifier": "prediction-kv31-surface-expression-reduced", "role": "prediction", "children": [ { "type": "Text", "value": "If the A421V variant impairs Kv3.1 surface trafficking — rather than channel gating per se — then heterozygous Kcnc1-A421V/+ PV-INs should show a measurable reduction in the membrane-localized fraction of Kv3.1 protein, accompanied by relative enrichment of cytosolic Kv3.1 (likely in the endoplasmic reticulum). Quantitatively, the membrane:cytosol fluorescence intensity ratio measured by immunohistochemistry should be significantly lower in mutant PV-INs. As a corollary, the voltage-dependence of activation and the activation kinetics of the residual K+ current should not differ between WT and mutant, because the channels that do reach the surface are predominantly WT homotetramers (or contain functional channels with normal gating)." } ], "panel": [ "prediction" ], "relations": [ { "xref": "hypothesis-a421v-causes-kv31-lof", "relationType": "cito:citesAsSourceDocument" } ], "metadata": { "uuid": "f80417c3-ece7-4792-9e83-0b3f92d26ac2", "concepts": [ "prediction", "membrane trafficking", "immunohistochemistry", "voltage-dependence", "activation kinetics", "Kv3.1" ], "displayClaim": "If A421V is a trafficking lesion, mutant PV-INs should show reduced membrane:cytosol Kv3.1 ratio with preserved voltage-dependence and gating kinetics of the residual current." } }, { "type": "Claim", "identifier": "prediction-network-hyperexcitability-in-vivo", "role": "prediction", "children": [ { "type": "Text", "value": "If PV-IN dysfunction reduces effective perisomatic inhibition in vivo, then awake Kcnc1-A421V/+ mice should show measurable signatures of cortical hyperexcitability by two-photon calcium imaging: (i) paroxysmal hypersynchronous neuropil discharges not present in WT, reflecting brief network-wide bursts of activity, and (ii) elevated calcium transient frequency in PV-negative (excitatory) cells during low-arousal states, reflecting tonic disinhibition. These signatures should be state-dependent — present during quiet rest, when tonic inhibition normally dominates — and may be masked or compensated during active arousal states (e.g. running) when other modulatory inputs dominate cortical state." } ], "panel": [ "prediction" ], "relations": [ { "xref": "hypothesis-pv-dysfunction-drives-encephalopathy", "relationType": "cito:citesAsSourceDocument" } ], "metadata": { "uuid": "6830e27e-2b1a-4d64-a35f-cb2ce47f0871", "concepts": [ "prediction", "in vivo calcium imaging", "hypersynchronous discharge", "perisomatic inhibition", "network hyperexcitability", "state-dependence" ], "displayClaim": "Awake Kcnc1-A421V/+ mice should show two-photon signatures of cortical disinhibition: paroxysmal hypersynchronous discharges (mutant-only) and elevated PV-negative cell activity during quiet rest." } }, { "type": "Claim", "identifier": "prediction-progressive-synaptic-failure", "role": "prediction", "children": [ { "type": "Text", "value": "If PV-IN spike output is impaired from juvenile stages but the synaptic terminal release machinery requires further developmental maturation (or accumulates pathological adaptations) to manifest a measurable phenotype, then PV-IN→excitatory unitary inhibitory synaptic transmission should be normal at juvenile stages (P16–21) and altered at young adult stages (P32–42). The adult alteration should carry a presynaptic signature consistent with altered release dynamics — for example, increased uIPSC amplitude with reduced paired-pulse ratio (enhanced initial release probability with faster depression). The temporal dissociation is a refinement of the disease-mechanism hypothesis: it specifies that the inhibitory failure is developmentally emergent, not congenital, at the synaptic level." } ], "panel": [ "prediction" ], "relations": [ { "xref": "hypothesis-pv-dysfunction-drives-encephalopathy", "relationType": "cito:citesAsSourceDocument" } ], "metadata": { "uuid": "17e60029-7f39-40d7-b4ea-8b6f83179baa", "concepts": [ "prediction", "synaptic transmission", "paired-pulse ratio", "developmental progression", "juvenile vs adult" ], "displayClaim": "PV-IN→excitatory unitary inhibitory transmission should be intact at juvenile stages but altered at young adult stages — a developmentally emergent synaptic failure." } }, { "type": "Claim", "identifier": "prediction-pv-in-firing-impaired", "role": "prediction", "children": [ { "type": "Text", "value": "If Kv3.1 LOF selectively impairs the cell type that depends on it, then PV-INs in Kcnc1-A421V/+ mice should show reduced maximal sustained firing frequency, slower AP downstroke (reflecting impaired repolarization), and prolonged AP half-duration (APD50) under whole-cell current-clamp recording. Passive membrane properties (resting Vm, input resistance) and AP threshold should be preserved, because Kv3 channels operate at suprathreshold voltages and are not the dominant determinants of the resting state. The phenotype should be present at juvenile stages (P16–21), before any secondary network adaptations have occurred, as a cell-autonomous consequence of reduced Kv3.1 current." } ], "panel": [ "prediction" ], "relations": [ { "xref": "hypothesis-pv-in-selective-vulnerability", "relationType": "cito:citesAsSourceDocument" } ], "metadata": { "uuid": "26becfa9-773d-48d3-a7ba-b14998a9d145", "concepts": [ "prediction", "PV interneurons", "maximal firing", "AP waveform", "cell-autonomous", "juvenile" ], "displayClaim": "Kcnc1-A421V/+ PV-INs should show reduced maximal firing, slower AP downstroke, and prolonged APD50 — with preserved passive membrane properties — at juvenile stages." } }, { "type": "Claim", "identifier": "prediction-pv-in-k-current-reduced", "role": "prediction", "children": [ { "type": "Text", "value": "If KCNC1-A421V is a Kv3.1 loss-of-function variant, heterozygous PV-INs in the Kcnc1-A421V/+ knock-in mouse should show a quantitatively measurable reduction in voltage-gated potassium current density relative to WT littermates, measured by whole-cell or nucleated macropatch recording in the voltage range where Kv3 channels carry the dominant outward current (positive to ~0 mV). The reduction should be larger than the 50% expected from simple haploinsufficiency, because Kv3 channels function as obligate tetramers and a dominant-negative mutant subunit incorporated into heteromeric tetramers can disable more than half of channel surface delivery." } ], "panel": [ "prediction" ], "relations": [ { "xref": "hypothesis-a421v-causes-kv31-lof", "relationType": "cito:citesAsSourceDocument" } ], "metadata": { "uuid": "9205b93d-7a48-40b8-9bbb-290f859eaa61", "concepts": [ "prediction", "K+ current density", "PV interneurons", "heterozygous expression", "dominant-negative" ], "displayClaim": "Heterozygous Kcnc1-A421V/+ PV-INs should show reduced voltage-gated K+ current density, by an amount greater than 50% if the variant acts dominant-negatively." } }, { "type": "Claim", "identifier": "prediction-seizures-and-sudep", "role": "prediction", "children": [ { "type": "Text", "value": "If the inhibitory failure produced by Kv3.1 LOF is sufficient to drive the encephalopathy phenotype, then Kcnc1-A421V/+ mice should exhibit (i) spontaneous convulsive seizures captured on continuous video-EEG, (ii) seizure-induced sudden death (SUDEP) at high penetrance, and (iii) premature mortality with all mutants dying before reaching natural lifespan endpoints. The seizure types should match the spectrum reported in human KCNC1 DEE (myoclonic events, generalized tonic-clonic), and the SUDEP events should be preceded by tonic-clonic seizures with hindlimb extension — the canonical mouse SUDEP signature." } ], "panel": [ "prediction" ], "relations": [ { "xref": "hypothesis-pv-dysfunction-drives-encephalopathy", "relationType": "cito:citesAsSourceDocument" } ], "metadata": { "uuid": "c09c89af-97d8-41f2-9fb7-2aaa6ed339b6", "concepts": [ "prediction", "spontaneous seizures", "SUDEP", "premature mortality", "video-EEG", "translational fidelity" ], "displayClaim": "Kcnc1-A421V/+ mice should show spontaneous convulsive seizures, SUDEP events, and premature mortality recapitulating the human KCNC1 DEE phenotype." } }, { "type": "Claim", "identifier": "pv-in-ap-waveform-altered-downstroke-apd50", "role": "empirical", "children": [ { "type": "Text", "value": "PV-INs from Kcnc1-A421V/+ mice show significantly reduced AP downstroke velocity and prolonged AP half-duration (APD50) relative to WT at both juvenile (P16–21, **p=0.0012 downstroke; **p=0.0053 APD50) and adult (P32–42, **p=0.0051 downstroke; ***p<0.001 APD50) stages, while passive membrane properties are largely preserved." } ], "epistemicStrength": "strong", "relations": [ { "xref": "prediction-pv-in-firing-impaired", "relationType": "claimrel:tests" }, { "xref": "pv-ins-impaired-maximal-firing", "relationType": "claimrel:interprets" }, { "xref": "prediction-pv-in-firing-impaired", "relationType": "cito:confirms" }, { "xref": "pv-ins-impaired-maximal-firing", "relationType": "cito:supports" }, { "xref": "pv-ins-reduced-k-current-density", "relationType": "claimrel:requires" } ], "metadata": { "uuid": "04db8b33-39ce-43b1-8df4-63a156fbc874", "concepts": [ "action potential waveform", "downstroke velocity", "APD50", "Kv3.1", "PV interneurons", "repolarization" ] } }, { "type": "Claim", "identifier": "pv-in-inhibitory-synapse-altered-adult", "role": "empirical", "children": [ { "type": "Text", "value": "In adult (P32–42) Kcnc1-A421V/+ mice, PV-IN-mediated uIPSC magnitude is significantly increased relative to WT (**p<0.01 at 20 Hz, *p<0.05 at 40 and 80 Hz), and paired-pulse ratio (uIPSC2/uIPSC1) is significantly reduced across frequencies (*p<0.05), indicating developmentally emergent synaptic dysfunction in inhibitory neurotransmission." } ], "epistemicStrength": "strong", "relations": [ { "xref": "prediction-progressive-synaptic-failure", "relationType": "claimrel:tests" }, { "xref": "prediction-progressive-synaptic-failure", "relationType": "cito:confirms" }, { "xref": "hypothesis-pv-dysfunction-drives-encephalopathy", "relationType": "cito:confirms" }, { "xref": "pv-in-inhibitory-synapse-intact-juvenile", "relationType": "cito:extends" }, { "xref": "inhibitory-dysfunction-progresses-to-adulthood", "relationType": "cito:supports" } ], "metadata": { "uuid": "bd91acf8-a01d-4713-8382-8a0757cbd86a", "concepts": [ "inhibitory synaptic transmission", "uIPSC", "PV interneurons", "paired-pulse ratio", "adult", "Kv3.1", "synaptic depression" ] } }, { "type": "Claim", "identifier": "pv-in-inhibitory-synapse-intact-juvenile", "role": "empirical", "children": [ { "type": "Text", "value": "PV-IN-mediated inhibitory synaptic transmission is not significantly altered in juvenile (P16–21) Kcnc1-A421V/+ mice: failure rates, uIPSC magnitudes at 20/40/80 Hz, paired-pulse ratios, and synaptic latency are all not significantly different from WT (32.8% connection rate WT vs 34.9% Kcnc1-A421V/+; n=21/64 and 15/43 connected pairs respectively)." } ], "epistemicStrength": "strong", "relations": [ { "xref": "pv-in-inhibitory-synapse-altered-adult", "relationType": "cito:disagreesWith" }, { "xref": "prediction-progressive-synaptic-failure", "relationType": "claimrel:tests" }, { "xref": "alt-inhibitory-dysfunction-present-juvenile", "relationType": "claimrel:rulesOut" }, { "xref": "inhibitory-dysfunction-progresses-to-adulthood", "relationType": "cito:supports" } ], "metadata": { "uuid": "dbc34885-27d0-4b6e-afbb-6a34befb9b98", "concepts": [ "inhibitory synaptic transmission", "uIPSC", "PV interneurons", "paired-pulse ratio", "juvenile", "Kv3.1" ] } }, { "type": "Claim", "identifier": "pv-ins-impaired-maximal-firing", "role": "empirical", "children": [ { "type": "Text", "value": "PV-INs from Kcnc1-A421V/+ mice exhibit impaired maximal firing frequency in patch-clamp recordings compared to wild-type, consistent with Kv3.1 loss-of-function reducing the fast repolarization that enables high-frequency firing." } ], "epistemicStrength": "strong", "relations": [ { "xref": "excitatory-neurons-unaffected-juvenile", "relationType": "cito:disagreesWith" }, { "xref": "prediction-pv-in-firing-impaired", "relationType": "claimrel:tests" }, { "xref": "prediction-pv-in-firing-impaired", "relationType": "cito:confirms" }, { "xref": "hypothesis-pv-in-selective-vulnerability", "relationType": "cito:confirms" } ], "metadata": { "uuid": "894a5d58-bca8-4b16-b22b-76b64db1e3e5", "concepts": [ "Kv3.1", "maximal firing frequency", "PV interneurons", "excitability", "fast-spiking" ] } }, { "type": "Claim", "identifier": "pv-ins-reduced-k-current-density", "role": "empirical", "children": [ { "type": "Text", "value": "Parvalbumin-positive interneurons (PV-INs) in Kcnc1-A421V/+ mice show significantly reduced potassium current density in whole-cell patch-clamp recordings, consistent with loss-of-function of Kv3.1 channel." } ], "epistemicStrength": "strong", "relations": [ { "xref": "prediction-pv-in-k-current-reduced", "relationType": "claimrel:tests" }, { "xref": "prediction-pv-in-k-current-reduced", "relationType": "cito:confirms" }, { "xref": "hypothesis-a421v-causes-kv31-lof", "relationType": "cito:confirms" } ], "metadata": { "uuid": "b29d38ec-0fb8-4a7b-863e-470dd3eb378b", "concepts": [ "Kv3.1", "potassium current", "PV interneurons", "patch-clamp", "loss-of-function" ] } }, { "type": "Claim", "identifier": "rtn-neurons-impaired-excitability", "role": "empirical", "children": [ { "type": "Text", "value": "Parvalbumin-positive reticular thalamic nucleus (RTN) neurons from juvenile (P16–21) Kcnc1-A421V/+ mice generate fewer rebound APs in response to hyperpolarizing current and show attenuated frequency-current relationship (*p=0.0109), with significantly reduced AP downstroke velocity (*p=0.034) but preservation of other membrane properties." } ], "epistemicStrength": "strong", "relations": [ { "xref": "prediction-impairment-grades-with-kv31-dependence", "relationType": "claimrel:tests" }, { "xref": "prediction-impairment-grades-with-kv31-dependence", "relationType": "cito:confirms" }, { "xref": "hypothesis-pv-in-selective-vulnerability", "relationType": "cito:confirms" }, { "xref": "pv-ins-impaired-maximal-firing", "relationType": "cito:extends" } ], "metadata": { "uuid": "37d23efe-7e34-48aa-82ff-b7f3ef45751c", "concepts": [ "reticular thalamic nucleus", "RTN", "PV neurons", "Kv3.1", "rebound firing", "excitability" ] } }, { "type": "Claim", "identifier": "scope-a421v-knockin-mouse", "role": "scope", "children": [ { "type": "Text", "value": "All claims about the cellular, circuit, and behavioral phenotype derive from a specific experimental envelope: a novel transgenic mouse with conditional expression of the Kcnc1-A421V missense variant, used in the global heterozygous configuration (Kcnc1-A421V/+) achieved by crossing to Actb-Cre, and further crossed to Pvalb-tdTomato for PV-IN identification (triple transgenic for ex vivo electrophysiology). Patch-clamp electrophysiology is performed in two age windows (juvenile P16–21, young adult P32–42) on neocortex (predominantly somatosensory), with additional recordings in deep cortical layer V and reticular thalamic nucleus. In vivo two-photon calcium imaging uses AAV9-syn-jGCaMP8m or soma-tagged jGCaMP8m with S5E2-driven tdTomato for PV-ID, in awake head-fixed somatosensory cortex of mice >P50. Continuous video-EEG uses DSI wireless telemetry over 2–7 days at P24–48. Behavioral testing (Barnes maze, Y-maze) is performed at P35–65. Generalisation beyond the heterozygous knock-in configuration (e.g. to homozygous, conditional cell- type-restricted, or human-equivalent allelic series), beyond the C57BL/6J background, or beyond the specific age windows tested is not established by this paper. Verification path: G-Node deposit (https://doi.org/10.12751/g-node.bqni9h) contains the analyzed Excel summary for figs 3-7 electrophysiology; raw data plus other modalities require the 68 GiB ZIP." } ], "panel": [ "scope" ], "epistemicStrength": "strong", "relations": [ { "xref": "kcnc1-wet-lab-primary-claims", "relationType": "claimrel:scopes" }, { "xref": "a421v-mice-die-before-122d", "relationType": "claimrel:scopes" }, { "xref": "a421v-weight-reduced-milestones-normal", "relationType": "claimrel:scopes" }, { "xref": "a421v-spatial-learning-working-memory-impaired", "relationType": "claimrel:scopes" }, { "xref": "pv-ins-reduced-k-current-density", "relationType": "claimrel:scopes" }, { "xref": "a421v-kv31-membrane-trafficking-impaired", "relationType": "claimrel:scopes" }, { "xref": "pv-ins-impaired-maximal-firing", "relationType": "claimrel:scopes" }, { "xref": "pv-in-ap-waveform-altered-downstroke-apd50", "relationType": "claimrel:scopes" }, { "xref": "layer-v-pv-ins-subtle-impairment", "relationType": "claimrel:scopes" }, { "xref": "rtn-neurons-impaired-excitability", "relationType": "claimrel:scopes" }, { "xref": "excitatory-neurons-unaffected-juvenile", "relationType": "claimrel:scopes" }, { "xref": "excitatory-neurons-unaffected-adult", "relationType": "claimrel:scopes" }, { "xref": "pv-in-inhibitory-synapse-intact-juvenile", "relationType": "claimrel:scopes" }, { "xref": "pv-in-inhibitory-synapse-altered-adult", "relationType": "claimrel:scopes" }, { "xref": "inhibitory-dysfunction-progresses-to-adulthood", "relationType": "claimrel:scopes" }, { "xref": "in-vivo-hypersynchronous-discharges-mutant-only", "relationType": "claimrel:scopes" }, { "xref": "in-vivo-pv-minus-transient-frequency-increased", "relationType": "claimrel:scopes" }, { "xref": "spontaneous-seizures-and-sudep-kcnc1", "relationType": "claimrel:scopes" } ], "metadata": { "uuid": "33883d00-c963-41b8-a13d-ca9e2cb8b1b2", "concepts": [ "paradigm scope", "knock-in mouse", "heterozygous", "age windows", "somatosensory cortex", "reticular thalamic nucleus" ], "displayClaim": "All findings derive from the Kcnc1-A421V/+ heterozygous knock-in mouse on C57BL/6J, measured at P16-21 and P32-42 (ex vivo) and >P50 (in vivo); G-Node-deposited." } }, { "type": "Claim", "identifier": "spontaneous-seizures-and-sudep-kcnc1", "role": "empirical", "children": [ { "type": "Text", "value": "8 of 12 Kcnc1-A421V/+ mice exhibit convulsive spontaneous seizures on video-EEG (mean 0.62±0.24/day, duration 32.4±15.7 s) with zero seizures in 4/4 WT controls; 4 seizure-induced sudden death events are captured, each preceded by a generalized tonic-clonic seizure with hindlimb extension, recapitulating SUDEP in human KCNC1 DEE." } ], "epistemicStrength": "strong", "relations": [ { "xref": "prediction-seizures-and-sudep", "relationType": "claimrel:tests" }, { "xref": "a421v-mice-die-before-122d", "relationType": "claimrel:interprets" }, { "xref": "prediction-seizures-and-sudep", "relationType": "cito:confirms" }, { "xref": "hypothesis-pv-dysfunction-drives-encephalopathy", "relationType": "cito:confirms" }, { "xref": "a421v-mice-die-before-122d", "relationType": "cito:supports" }, { "xref": "in-vivo-hypersynchronous-discharges-mutant-only", "relationType": "cito:extends" } ], "metadata": { "uuid": "b066dc9f-dd75-43a8-9692-1005de9d2d30", "concepts": [ "spontaneous seizures", "SUDEP", "video-EEG", "generalized tonic-clonic", "KCNC1", "epileptic encephalopathy" ] } } ] } ], "title": [ { "type": "Text", "value": "Impaired excitability of fast-spiking neurons in a novel mouse model of KCNC1 epileptic encephalopathy" } ] }