Activity-Dependent Regulation of PGC-1α in PV+ Interneurons Protocol
Phase 1: Primary Cortical Culture Preparation (Days 1-7)
Cell Culture: Dissect cortex from P14-P18 C57BL/6 mice (both sexes). Dissociate neurons via papain digestion (20 U/mL, 37°C, 30 min). Plate at density 80,000 cells/cm² on poly-D-lysine/laminin-coated 12-well plates. Culture in Neurobasal-A supplemented with B-27, 0.5 mM L-glutamine, and 1× penicillin/streptomycin. Maintain at 37°C, 5% CO₂.
PV+ Interneuron Identification: At DIV 14, verify PV+ interneuron population via immunocytochemistry: anti-parvalbumin (1:500, Abcam ab114246) and anti-GAD67 (1:200, Millipore MABN60). Count PV+ cells as percentage of DAPI+ nuclei (target: 15-25% PV+).
...Activity-Dependent Regulation of PGC-1α in PV+ Interneurons Protocol
Phase 1: Primary Cortical Culture Preparation (Days 1-7)
Cell Culture: Dissect cortex from P14-P18 C57BL/6 mice (both sexes). Dissociate neurons via papain digestion (20 U/mL, 37°C, 30 min). Plate at density 80,000 cells/cm² on poly-D-lysine/laminin-coated 12-well plates. Culture in Neurobasal-A supplemented with B-27, 0.5 mM L-glutamine, and 1× penicillin/streptomycin. Maintain at 37°C, 5% CO₂.
PV+ Interneuron Identification: At DIV 14, verify PV+ interneuron population via immunocytochemistry: anti-parvalbumin (1:500, Abcam ab114246) and anti-GAD67 (1:200, Millipore MABN60). Count PV+ cells as percentage of DAPI+ nuclei (target: 15-25% PV+).
Phase 2: Activity Manipulation Paradigm (Days 8-14)
Optogenetic Stimulation: Transduce neurons at DIV 7 with AAV9-CaMKIIa-ChrimsonR-tdTomato (Addgene #62722) or AAV9-CaMKIIa-eArchT3.0-eYFP (control). Apply 8 Hz light pulses (473 nm, 10 ms pulses, 5 s on/5 s off for 30 min/day) for 7 consecutive days.
Chemogenetic Modulation: For complementary experiments, apply DREADD hM3Dq (CNO, 5 μM) or hM4Di for 6 hours to modulate network activity. Measure spontaneous excitatory postsynaptic currents (sEPSCs) via patch clamp at DIV 14, 16, and 18.
Phase 3: PGC-1α Expression Analysis (Days 15-21)
Molecular Analysis: Extract protein at 4 timepoints (baseline DIV7, post-stimulation DIV14/16/18). Probe with anti-PGC-1α (1:500, Abcam ab191695) and anti-β-actin (1:5000). Quantify via western blot with HRP-conjugated secondary antibodies and chemiluminescent detection (GE ECL). Normalize PGC-1α signal to β-actin loading control.
Mitochondrial Function: Measure mitochondrial mass via MitoTracker Deep Red FM (100 nM, 30 min, 37°C) and MitoSOX Red (5 μM, 10 min) for superoxide detection. Analyze via flow cytometry (Attune NxT) or high-content imaging (IN Cell 2200).
Phase 4: Functional Validation (Days 22-28)
Respirometry: Measure oxygen consumption rate (OCR) via Seahorse XFe96 Analyzer. Sequence: oligomycin (1 μg/mL), FCCP (0.75 μM), rotenone/antimycin A (0.5 μM). Calculate basal respiration, max capacity, and spare respiratory capacity.
ATF4 Target Analysis: For mechanistic studies, include PGC-1α target gene panel: ATF4, ERR-α, NRF-1, NRF-2, and mitochondrial biogenesis markers (TFAM, COXI, ATP5A). Verify via qRT-PCR (ΔΔCt method).