Protocol Code: SCF-CRO-ASSAY-N6K7-EPI-GMS-0001
Classification: GLP-Compatible Ion Channel, Neuronal, and Translational Assay Suite
I. OVERVIEW
This document provides CRO-executable assay protocols with exact experimental conditions for:
- Nav1.6 inhibition (patch-clamp)
- Kv7.2/7.3 activation (patch-clamp)
- Selectivity panel (Nav1.1, Nav1.5, hERG)
- Neuronal network activity (MEA)
- Multi-ion flux imaging
- Redox coupling validation
- Cytotoxicity & safety screens
All protocols are aligned for IND-enabling pharmacology.
II. ASSAY 1 — Nav1.6 PATCH-CLAMP (PRIMARY MoA)
Objective
Quantify inhibition of persistent and resurgent Na⁺ currents in Nav1.6-expressing cells.
System
- Cell line: HEK293 stably expressing human SCN8A (Nav1.6)
- Passage: ≤20
- Culture: DMEM + 10% FBS + G418 (500 µg/mL)
Solutions
External (Bath) Solution
- NaCl: 140 mM
- KCl: 4 mM
- CaCl₂: 2 mM
- MgCl₂: 1 mM
- HEPES: 10 mM
- Glucose: 10 mM
- pH: 7.4 (NaOH)
Internal (Pipette) Solution
- CsF: 120 mM
- NaCl: 10 mM
- EGTA: 10 mM
- HEPES: 10 mM
- pH: 7.2 (CsOH)
Recording Conditions
Parameter | Value |
Temperature | 22–24°C |
Holding potential | −80 mV |
Test pulse | −20 mV |
Pulse duration | 20 ms |
Sampling rate | 20 kHz |
Filter | 5 kHz |
Compound Testing
- Concentration range: 1 nM – 30 µM (8-point curve)
- Incubation: 3 minutes pre-application
- Replicates: n = 6 cells per concentration
Endpoints
- Peak current inhibition (%)
- Persistent current reduction (%)
- IC₅₀ calculation (nonlinear regression)
Acceptance Criteria
- Z’ factor ≥ 0.5
- Seal resistance ≥ 1 GΩ
- Series resistance < 10 MΩ
III. ASSAY 2 — Kv7.2/7.3 ACTIVATION (SECONDARY MoA)
System
- Cell line: CHO cells expressing KCNQ2/KCNQ3
- Culture: Ham’s F-12 + 10% FBS
Solutions
External
- KCl: 5 mM
- NaCl: 135 mM
- CaCl₂: 2 mM
- MgCl₂: 1 mM
- HEPES: 10 mM
- pH: 7.4
Internal
- KCl: 140 mM
- MgCl₂: 2 mM
- EGTA: 5 mM
- HEPES: 10 mM
- pH: 7.2
Recording Protocol
Parameter | Value |
Holding potential | −60 mV |
Step protocol | −60 → −20 mV |
Duration | 500 ms |
Sampling | 10 kHz |
Compound Testing
- Range: 10 nM – 30 µM
- Incubation: 5 minutes
- Positive control: Retigabine (10 µM)
Endpoints
- Current amplitude increase (%)
- EC₅₀
- Shift in activation curve (V½)
IV. ASSAY 3 — SELECTIVITY PANEL
Targets
- Nav1.1 (GABAergic preservation)
- Nav1.5 (cardiac safety)
- hERG (QT risk)
Conditions
- Same patch-clamp setup as Nav1.6
- Concentration: up to 30 µM
Acceptance Thresholds
Target | Threshold |
Nav1.1 | <20% inhibition @ 10 µM |
Nav1.5 | <10% inhibition @ 10 µM |
hERG | IC₅₀ > 10 µM |
V. ASSAY 4 — NEURONAL NETWORK ACTIVITY (MEA)
System
- Human iPSC-derived cortical neurons
- प्लेट density: 50,000 cells/well (48-well MEA plate)
Culture Conditions
- मीडिया: Neurobasal + B27 + Glutamax
- Maturation: 21 days in vitro (DIV21)
Recording Conditions
Parameter | Value |
तापमान | 37°C |
CO₂ | 5% |
Recording duration | 10 min baseline + 30 min post-dose |
Compound Testing
- Concentrations: 0.1 µM, 1 µM, 10 µM
- Vehicle: 0.1% DMSO
Endpoints
- Spike rate
- Burst frequency
- Network synchrony index
Expected Outcome
- ↓ burst frequency
- ↓ synchrony
- Stabilized firing pattern
VI. ASSAY 5 — MULTI-ION FLUX IMAGING
System
- Primary neurons or iPSC neurons
Indicators
Ion | Dye |
Ca²⁺ | Fluo-4 AM (5 µM) |
Na⁺ | SBFI-AM (10 µM) |
K⁺ | PBFI-AM (5 µM) |
Loading Conditions
- Incubation: 30 min at 37°C
- Wash: 3× with buffer
Imaging
Parameter | Value |
Microscope | Confocal |
Frame rate | 1–5 Hz |
Duration | 10–20 min |
Endpoints
- Ca²⁺ spike amplitude
- Na⁺ influx rate
- K⁺ clearance
VII. ASSAY 6 — REDOX & ELECTRON FLOW
System
- Live neurons
Measurements
Marker | Method |
NADH | Autofluorescence |
ROS | DCFDA (10 µM) |
Conditions
- Incubation: 30 min
- Temperature: 37°C
Endpoints
- ROS reduction (%)
- NADH/FAD ratio normalization
VIII. ASSAY 7 — CYTOTOXICITY
Assay
- CellTiter-Glo
Conditions
Parameter | Value |
Cell density | 10,000 cells/well |
Incubation | 24–72 hours |
Concentration | up to 100 µM |
Acceptance
- Cell viability ≥80% at 10 µM
IX. DATA ANALYSIS
Statistical Methods
- Nonlinear regression (IC₅₀, EC₅₀)
- ANOVA (multi-group comparisons)
- n ≥ 3 independent experiments
X. QUALITY CONTROL
Controls
Type | Example |
Positive | Retigabine (Kv7), Phenytoin (Nav) |
Negative | Vehicle (0.1% DMSO) |
Reproducibility Criteria
- CV < 20%
- Repeat across ≥3 batches
XI. CRO EXECUTION NOTES
Required Equipment
- Patch-clamp rigs (Axopatch / equivalent)
- MEA system (Axion Maestro)
- Confocal microscope
- Plate reader (luminescence)
Timeline per Assay
Assay | Duration |
Patch-clamp | 2–3 weeks |
MEA | 3–4 weeks |
Ion imaging | 2 weeks |
Toxicity | 1–2 weeks |
XII. INTEGRATED SCF LOGIC SUMMARY
Dual ion-channel validation → ion flux normalization → neuronal stabilization → translational readiness
MASTER REGISTRY INDEX
- SCF-CRO-ASSAY-N6K7-EPI-GMS-0001 — CRO Assay Protocols
- SCF-TLC-DPK-N6K7-EPI-GMS-0001 — Lead Candidate Dossier
- SCF-MCC-N6K7-EPI-GMS-0001 — Medicinal Chemistry Campaign
- SCF-ADP-N6K7-EPI-GMS-0001 — API Discovery Profile
- SCF-MOGEM-EPI-GMS-0001 — Electrophysiological Modeling
- SCF-SEF-MD-0001 — Synergistic Evaluation Framework
If you want next, I can generate:
- GLP-compliant study protocols (FDA submission format)
- CRO vendor selection + budget estimates
- Full IND module 4 (pharmacology/toxicology write-up)
- Digital twin simulation of assay outcomes