An In Vitro Fluorescence-Based Assay to Measure Plasma Membrane Resealing Efficiency

Abstract

Source: Lam, J. G., et al. High-throughput Measurement of Plasma Membrane Resealing Efficiency in Mammalian Cells. J. Vis. Exp. (2019).

This video demonstrates an assay to study the plasma membrane resealing efficiency in mammalian cells. The cells are exposed to a bacterial pore-forming toxin, which forms pores in the cell membrane. In the presence of extracellular calcium ions, the pore causes calcium influx, inducing membrane-resealing events. The resealing efficiency is assessed using DNA-binding propidium iodide dye, which only enters cells without a resealed membrane.

Protocol

1. Preparation Cell Plating Note: Human cervical epithelial cells, HeLa and HeLa expressing Histone 2B-GFP (H2B-GFP), were used in this protocol, but this assay can be adapted to other mammalian cells. Detach adherent cells from a 75 cm2 cell culture flask by washing the cells with 2 mL of Trypsin-EDTA 0.25%. Replace the used trypsin with 2 mL of fresh trypsin-EDTA 0.25%. Incubate the cells at 37 ˚C for 5 min until the cells have …

Representative Results

Figure 1: Experimental design. The flow diagram depicts a representative plate design configured to test the effect of seven test conditions in comparison to control non-treated cells. Additional controls should be included if appropriate, as for example drug vehicles. Cells are plated (plate 1) 24 h prior to the experiment. On the day of the experiment, cells in plate 1 are washed with M1 or M2 …

Materials

SpectraMax i3x Multi-Mode Microplate Reader	Molecular Devices	i3x
MiniMax 300 Imaging cytometer	Molecular Devices	5024062
TO-PRO-3	ThermoFisher Scientific	T3605
Propidium Iodide	ThermoFisher Scientific	P3566
HeLa	ATCC	CCL2
HeLa H2B-GFP	Millipore	SCC117
Trypsin-EDTA 0.25%	ThermoFisher Scientific	25200056
96-well Corning flat bottom black polystyrene tissue culture treated plate	Corning	3603
Hanks' balanced Salts	Sigma-Aldrich	H4891
EGTA	ISC BioExpress	0732-100G
HEPES	Fisher Scientific	BP310-500
D-(+)-Glucose, HybriMax	Sigma-Aldrich	G5146-1KG