This video demonstrates a simple technique for retinoic acid-induced neurogenesis in P19 mouse embryonic carcinoma cells. Retinoic acid activates transcription factors and triggers gene expression for neuronal differentiation.
Protocol
1. Aggregate Generation
Add 5 µL of RA (retinoic acid) (1 mM stock dissolved in 99.8% ethanol, stored at -20 °C) to the 10 mL of Differentiation Medium and mix well (final concentration of 0.5 µM RA). NOTE: RA is light-sensitive. A low concentration of ethanol does not affect cell differentiation.
Add 10 mL of Differentiation Medium (with RA) to the 100 mm non-treated culture dish (dedicated to suspension culture).
Seed the 1 x 106 cells in the 100 mm dish (Dish surface area 56.5 cm2).
Put the flask with cells into the incubator at 37 °C and 5% CO2 for 2 days to promote aggregate formation.
After 2 days, exchange the Differentiation Medium. Aspirate medium containing aggregates using a 10 mL pipette and transfer to a 15 mL tube at RT.
Allow the aggregates to settle by gravity for 1.5 min at RT.
Discard the supernatant.
Add a fresh 10 mL of Differentiation Medium with 0.5 µM RA using a 10 mL serological pipette. CAUTION: Do not pipette the cell aggregates up and down.
Seed the aggregates into a new 100 mm non-treated culture dish (dedicated to suspension culture).
Place the plate in the incubator (at 37 °C and 5% CO2) for 2 days.
2. Aggregates Dissociation
Aspirate the cell aggregates using a 10 mL pipette.
Transfer the aggregates to a 15 mL tube. Allow the cell aggregates to settle by gravity for 1.5 min.
Remove the supernatant.
Wash the aggregates with DMEM alone (serum- and antibiotic-free).
Allow the cell aggregates to settle by gravity sedimentation for 1.5 min at RT.
Aspirate the supernatant and add 2 mL of trypsin-EDTA (0.25%).
Place the cell aggregates into a water bath (37 °C) for 10 min. Agitate the aggregates gently every 2 min by tapping with a hand.
Stop the trypsinization process by adding 4 mL of Maintenance Medium.
Pipette the aggregates up and down 20 times using a 1 mL pipette.
Centrifuge cells for 5 min at 200 x g and RT.
Remove the supernatant and resuspend the cell pellet in 5 mL of Maintenance Medium.
Determine the cell number with a cell counter.
3. Plating Cells
Add 3 mL per well of Maintenance Medium to a 6-well plate.
Seed cells in the 6-well culture plate at a density of 0.5 x 106/well.
Incubate at 37 °C with 5% CO2 concentration.
Disclosures
The authors have nothing to disclose.
Materials
DMEM high glucose (4.5 g/L) with L-glutamine
Lonza
BE12-604Q
Ethanol 99.8%
Chempur
CHEM*613964202
Fetal Bovine Serum (FBS)
EURx
E5050-03
Penicillin/Streptomycin 10K/10K
Lonza
DE17-602E
Phosphate Buffered Saline (PBS), 1x concentrated without calcium and magnesium ions
Lonza
BE17- 517Q
Retinoic acid
Sigma- Aldrich
R2625-50MG
Dissolved in 99.8% ethanol; store in -20 °C up to 6 months
Trypsin 0.25% – EDTA in HBSS, without calcium and magnesium ions,with Phenol Red