Preparation of Pancreatic Acinar Cells for the Purpose of Calcium Imaging, Cell Injury Measurements, and Adenoviral Infection

Summary

We describe a reproducible method of preparing mouse pancreatic acinar cells from a mouse for the purpose of examining acinar cell calcium signals and cellular injury with physiologically and pathologically relevant stimuli. A method for adenoviral infection of these cells is also provided.

Abstract

The pancreatic acinar cell is the main parenchymal cell of the exocrine pancreas and plays a primary role in the secretion of pancreatic enzymes into the pancreatic duct. It is also the site for the initiation of pancreatitis. Here we describe how acinar cells are isolated from whole pancreas tissue and intracellular calcium signals are measured. In addition, we describe the techniques of transfecting these cells with adenoviral constructs, and subsequently measuring the leakage of lactate dehydrogenase, a marker of cell injury, during conditions that induce acinar cell injury in vitro. These techniques provide a powerful tool to characterize acinar cell physiology and pathology.

Introduction

Dynamic changes in cytosolic calcium are necessary for both physiological and pathological acinar cell events. These divergent effects of calcium are thought to result from distinct spatial and temporal patterns of calcium signaling ¹. For example, enzyme and fluid secretion from the acinar cell are linked to calcium spikes from a restricted region of the apical pole where secretion takes place ². In contrast, a global calcium wave followed by intense non-oscillatory calcium signals is associated with early pathological events which lead to acute pancreatitis ^3,4. These include intra-acinar protease activation, reduced enzyme s....

Protocol

1. Preparing Pancreatic Acinar Cells for Calcium Imaging

1. Prepare HEPES incubation buffer containing 20 mM HEPES, 95 mM NaCl, 4.7 mM KCl, 0.6 mM MgCl₂, 1.3 mM CaCl₂, 10 mM glucose, 2 mM glutamine, and 1 × minimum Eagle's medium non-essential amino acids. Adjust the final solution to pH 7.4 with NaOH.
2. Prepare a BSA incubation buffer by adding BSA (1% w/v final) to 25 ml of the HEPES incubation buffer (described above).
3. Prepare a collagenase digestion buffer by adding 1.1 mg/ml (200 Units/ml) type-4 collagenase and 1 mg/ml soybean trypsin inhibitor to 6 ml of BSA incubation buffer (described above).
4. Aci....

Results

An example of acinar cell calcium measurements in response to physiologic stimuli is provided in Figure 3. Acinar cells were loaded with the calcium dye Fluo-4 and perfused with the acetylcholine analogue carbachol (CCh; 1 μM)) ⁸. Cells responded in the form of a calcium wave which initiates in the apical region and propagates to the basolateral region ^3,9. Representative tracings shown in Figure 3B demonstrate the typical peak-plateau pattern commonly observed with.......

Discussion

The cell isolation method and subsequent assays depicted here represent powerful tools with which to study the physiological and pathophysiological features of the exocrine pancreas. The method for isolating dispersed pancreatic acinar cells was first described by Amsterdam and Jamieson in 1972 ¹¹. The methods presented here have been adapted from more recent isolation methods described by Van Acker and colleagues ¹². Although these techniques are highly reproducible and easily learned, there.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Mice	NCI	N/A	Male 20-30 grams; virtually any strain should yield comparable results.
HEPES	American Bioanalytical	AB00892
Sodium Chloride	J.T. Baker	3624-05
Potassium Chloride	J.T. Baker	3040-01
Magnesium Chloride	Sigma	M-8266
Calcium Chloride	Fischer	C79
Dextrose	J.T. Baker	1916-01
L-Glutamine	Sigma	G-8540
1X minimum Eagle's medium non-essential amino acid mixture	Gibco	11140-050
Sodium Hydroxide	EM	SX0593
Bovine Serum Albumin	Sigma	A7906
Collagenase	Worthington	4188
Soybean Trypsin Inhibitor	Sigma	T-9003
Carbon Dioxide	Matheson Gas	124-38-9
125 ml Erlenmeyer plastic flask	Crystalgen	26-0005
Dissection kit	Fine Science Tools	14161-10
70% Ethanol	LabChem	LC222102
P1000, P100, P10 pipettes	Gilson	FA10005P
Weighing boat	Heathrow Scientific	HS1420A
Plastic transfer pipettes	USA Scientific	1020-2500
15 ml conical tubes	BD Falcon	352095
50 ml conical tubes	BD Falcon	352070
1.5 ml micro-centrifuge tube	Fisher	05-408-129
0.65 ml micro-centrifuge tube	VWR	20170-293
22 x 22 mm glass coverslips	Fisher	032811-9
Nitric Acid	Fischer	A483-212
Hydrochloric Acid	Fischer	A142-212
Deionized water	N/A	N/A
18 x 18 mm coverslips	Fischer	021510-9
Laboratory film	Parafilm	PM-996
Fluo-4AM	Invitrogen	F14201
Dimethylsulfoxide	Sigma	D2650
Luer lock	Becton Dickinson	932777
60 ml syringe	BD Bioscience	DG567805
23 ¾ gauge needle	BD Bioscience	9328270
PE50 tubing	Clay Adam	PE50-427411
Flat head screwdriver	N/A	N/A
DMEM F-12, no Phenol Red	Gibco	21041-025
30.5 gauge needle	BD Bioscience	305106
5 CC syringe	BD Bioscience	309603
25 ml Erlenmeyer flask	Fischer	FB50025
Nylon mesh filter	Nitex	03-150/38	150 um pore size
48 well tissue culture plate	Costar	3548
96 well tissue culture plate	Costar	3795
6 well tissue culture plate	Costar	3506
Liquid nitrogen	Matheson Gas	7727-37-9
Cytotoxicity assay kit	Promega	G1782
Adeno-GFP	N/A	N/A	Gift from J. Williams
Equipment
Ring stand with clamps	United Scientific	SET462
Perifusion chamber	N/A	N/A	Designed by S.Z.H and colleagues at Yale University
Vacuum line	Manostat	72-100-000
Water bath with shaker	Precision Scientific	51220076
Confocal microscope	Zeiss	LSM 710
BioTek Synergy H1 plate reader	BioTek	11-120-534
Tissue culture hood	Nuaire	NU-425-600
Tissue culture Incubator	Thermo	3110