Generation of Lymphocytic Microparticles and Detection of their Proapoptotic Effect on Airway Epithelial Cells

Summary

Cell membrane–shed microparticles (MPs) are active biological vesicles that can be isolated and their pathophysiological effects investigated in various models. Here we describe a method for generating MPs derived from T lymphocytes (LMPs) and for demonstrating their proapoptotic effect on airway epithelial cells.

Abstract

Interest in the biological roles of cell membrane–derived vesicles in cell–cell communication has increased in recent years. Microparticles (MPs) are one such type of vesicles, ranging in diameter from 0.1 μm to 1 μm, and typically shed from the plasma membrane of eukaryotic cells undergoing activation or apoptosis. Here we describe the generation of T lymphocyte–derived microparticles (LMPs) from apoptotic CEM T cells stimulated with actinomycin D. LMPs are isolated through a multistep differential centrifugation process and characterized using flow cytometry. This protocol also presents an in situ cell death detection method for demonstrating the proapoptotic effect of LMPs on bronchial epithelial cells derived from mouse primary respiratory bronchial tissue explants. Methods described herein provide a reproducible procedure for isolating abundant quantities of LMPs from apoptotic lymphocytes in vitro. LMPs derived in this manner can be used to evaluate the characteristics of various disease models, and for pharmacology and toxicology testing. Given that the airway epithelium offers a protective physical and functional barrier between the external environment and underlying tissue, use of bronchial tissue explants rather than immortalized epithelial cell lines provides an effective model for investigations requiring airway tract tissue.

Introduction

Microparticles (MPs) are biologically active submicron membrane vesicles released following cell activation or apoptosis. MPs are derived from both healthy and damaged cells and are implicated in many physiological and pathological processes.¹ MPs have been detected not only in human plasma, but also in inflammatory and apoptotic tissue. The biological utility of cell membrane–derived MPs has been demonstrated in various settings, including cell signalling models and as pharmacological tools.^2,3 We previously demonstrated that LMPs derived from T lymphocytes following actinomycin D stimulation (to induce apoptosis) suppress angiogenesis and....

Protocol

NOTE: Male C57BL/6 mice (5–7 weeks old) are from Charles River Laboratories International, Inc. (St-Constant, Quebec, Canada.) and manipulated according to protocols approved by the CHU Sainte-Justine Animal Care Committee. Mouse bronchial tissue explants provide a good source of primary bronchial epithelial cells for investigating the proapoptotic effects of LMPs on epithelial cells. This protocol describes the in vitro generation of LMPs, as well as a method for detecting apoptotic epithelial cells on LMPs-treated bronchial tissue explants. This protocol consists of 3 sections.

1. LMPs Production and Characterization

Results

LMPs were characterized with annexin V staining¹⁰ by fluorescence-activated cell sorting (FACS) analysis and gated using 1 µm beads in which 97% of MPs (≤1 µm) were annexin-V-Cy5 positive (Figure 1A and 1B). Typically, about 2.5 mg of LMPs were obtained following this protocol. Bronchial tissue explants from C57BL/6 mice were subjected to vehicle and LMPs treatment. Histopathological analysis of bronchial sections revealed the effect of LMPs on the structural integrity of the bronchial epithel.......

Discussion

MPs are active mediators of intercellular cross talk and their study is promising in many areas of science.¹¹ This study presented a detailed protocol for in vitro large-scale generation of LMPs derived from an apoptotic T cell line. These MPs express a large repertoire of lymphocyte molecules and are biologically implicated in the regulation of cellular and tissue homeostasis. However, LMPs derived from different sources may be biologically different.^4,9,12,13

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Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
LMPs production and characterization
CEM T cells	ATCC	CCL-119
X-VIVO 15 medium	Cambrex, Walkersville	04-744Q
Flask T75	Sarstedt	83.1813.502
Flask T175	Sarstedt	83.1812.502
Actinomycin D	Sigma Chemical Co.	A9415-2mg
PBS	Lifetechnologies	14190-144
0.22 µm filter	Sarstedt	83.1826.001
Annexin-VCy5	BD Pharmagen	559933
FACS flow solution	BD Bio-sciences	342003
Fluorescent microbeads (1 µm)	Molecular Probes	T8880
Polysterene counting beads (7 µm)	Bangs laboratories	PS06N/6994
Polypropylene FACS tubes	Falcon	352058
1 ml pipet	Fisher	13-678-11B
5 ml pipet	Falcon	357543
25 ml pipet	Ultident	DL-357551
1.5 ml conical polypropylene micro tube	Sarstedt	72.690
15 ml conical polypropylene tube	Sarstedt	62.554.205
50 ml conical polypropylene tube	Sarstedt	62.547.205
50 ml high speed polypropylene copolymer tube	Nalgene	3119-0050
250 ml high speed polypropylene bottle	Beckman	356011
Protein assay (Bradford assay)	Bio-Rad Laboratories	500-0006
Protein assay standard II	Bio-Rad Laboratories	500-0007
Test tube 16 x 100	VWR	47729-576
Test tube 12 x 75	Ultident	170-14100005B
Cell incubator	Mandel	Heracell 150
Low speed centrifuge	IEC	Centra8R
High speed centrifuge	Beckman	Avanti J8
High speed rotor for 250ml bottle	Beckman	JLA16.250
High speed rotor for 50ml tube	Beckman	JA30.50
Fow cytometry	BD Bio-sciences	FACS Calibur
Spectrophotometer	Beckman	Series 600
Bronchial tissue explants and sections
C57BL/6 mice (5-7 weeks old)	Charles River Laboratories, Inc.
Mouse Airway PrimaCell™ System:	CHI Scientific, Inc.	2-82001
Rib-Back Carbon Steel Scalpel Blades	Becton Dickinson AcuteCare	371310	#10
Scalpel Handle	Fine Science Tools Inc.	10003-12	#7
phase-contrast inverted microscope	Olympus Optical CO., LTD.	CK2
high O2 gas mixture	VitalAire Canada Inc.
modular incubator chamber	Billups-Rothenberg Inc.	MIC-101
MaxQ 4000 incubated orbital shaker	Barnstead Lab-Line,	SHKA4000-7
12-well tissue culture plate	Becton Dickinson and Company	353043
Plastic tissue culture dishes (100 mm)	Sarstedt, Inc.	83.1802
Surgical scissors	Fine Science Tools Inc.	14060-09	Straight, sharp, 9cm longth
Half-curved Graefe forceps	Fine Science Tools Inc.	11052-10
humidified CO2 incubator	Mandel Scientific Company Inc.	SVH-51023421
Histopathological examination
formalin formaldehyde	Sigma-Aldrich, Inc.	HT5011
paraffin	Fisher scientific  International, Inc.	T555
ethyl alcohol	Merck KGaA, Darmstadt	EX0278-1
glutaraldehyde	Sigma-Aldrich, Inc.	G6403
Cacodylate	Sigma-Aldrich, Inc.	31533
microscope slides	VWR Scientific Inc.	48300-025	25x75 mm
Xylene	Fisher scientific  International, Inc.	X5-4
Mayer's hematoxylin	Sigma-Aldrich, Inc.	MHS16	Funnel with filter paper
HCl	Fisher scientific  International, Inc.	A144s-500
eosin	Sigma-Aldrich, Inc.	HT110116	Funnel with filter paper
Permount™ Mounting Medium	Thermo Fisher Scientific Inc.	SP15-100
glass coverslip	surgipath medical industries, Inc.	84503	24×24 #1
TUNEL detection kit	In Situ Cell Death Detection, POD	11 684 817 910
oven	Despatch Industries Inc.	LEB-1-20
rotary Microtome	Leica Microsystems Inc.	RM2145
filter paper	Whatman International Ltd.	1003150	#3
Microscope	Nikon Imaging Japan Inc.	E800
staining dish complete	Wheaton Industries, Inc.	900200	including dish, rack, cover
1.5 ml eppendorf tube	Sarstedt Inc.	72.69	39x10 mm
Orbital and Reciprocating Water Bath	ExpotechUSA	ORS200
phosphate buffered saline	GIBCO	14190-144
fume hood	Nicram RD Service	3707E