Generation of ESC-derived Mouse Airway Epithelial Cells Using Decellularized Lung Scaffolds

Summary

This protocol efficiently directs mouse embryonic stem cell-derived definitive endoderm to mature airway epithelial cells. This differentiation technique uses 3-dimensional decellularized lung scaffolds to direct lung lineage specification, in a defined, serum-free culture setting.

Abstract

Lung lineage differentiation requires integration of complex environmental cues that include growth factor signaling, cell-cell interactions and cell-matrix interactions. Due to this complexity, recapitulation of lung development in vitro to promote differentiation of stem cells to lung epithelial cells has been challenging. In this protocol, decellularized lung scaffolds are used to mimic the 3-dimensional environment of the lung and generate stem cell-derived airway epithelial cells. Mouse embryonic stem cell are first differentiated to the endoderm lineage using an embryoid body (EB) culture method with activin A. Endoderm cells are then seeded onto decellularized scaffolds and cultured at air-liquid interface for up to 21 days. This technique promotes differentiation of seeded cells to functional airway epithelial cells (ciliated cells, club cells, and basal cells) without additional growth factor supplementation. This culture setup is defined, serum-free, inexpensive, and reproducible. Although there is limited contamination from non-lung endoderm lineages in culture, this protocol only generates airway epithelial populations and does not give rise to alveolar epithelial cells. Airway epithelia generated with this protocol can be used to study cell-matrix interactions during lung organogenesis and for disease modeling or drug-discovery platforms of airway-related pathologies such as cystic fibrosis.

Introduction

Directed differentiation of pluripotent cells to the lung lineage is dependent on precise signaling events in the microenvironment ^1,2. Due to the dynamic nature of this process it has been challenging to mimic the precise events of lung organogenesis in vitro. Recent reports have used step-wise lineage restriction strategies with soluble growth factor supplementation of two-dimensional cultures to achieve lung differentiation^3-8. In step-wise differentiation protocols, pluripotent cells, whether embryonic stem cells (ESC) or induced pluripotent stem cells, were first differentiated to the definitive endoderm germ layer. Endodermal cells....

Protocol

Animal experiments were carried out in accordance with the Animal Care Committee guidelines of the Hospital for Sick Children Research Institute.

1. Scaffold Preparation

1. Decellularization of lungs
   1. Euthanize adult Wistar rats using CO₂ chamber. Place animal in the chamber and start 100% CO₂ exposure at a fill rate of 10-30% of chamber volume per minute.
      1. Observe animal for unconsciousness; this will occur after approximately 2-3 min. If unconsciousness does not occur in this time period, check fill rate and chamber seal. Following unconsciousness, observe animal for faded eye color and lack of respiratio....

Results

As outlined in this protocol, robust differentiation of definitive endoderm to mature airway epithelial cells can be achieved using extended culture of seeded cells on decellularized lung scaffold sections. It is recommended that decellularized scaffolds be characterized to ensure (1) host cells are completely removed, and (2) extracellular matrix proteins are preserved prior to using scaffolds for differentiation. Decellularization can be assessed using tissue staining with hematoxylin a.......

Discussion

The protocol described here generates mature ESC-derived airway epithelia using only natural lung scaffolds to direct differentiation with no other supplementation. This culture setup is defined, serum-free, inexpensive, and reproducible. No growth factor supplementation of base differentiation media is required. Previously published methods for generating stem cell-derived lung epithelial cells have used 2-dimensional strategies with growth factor supplementation to promote lineage restriction^3,4,8,18,19. The.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Reagents
Perfusion solution	Sigma	H0777	10 U/ml heparin
Perfusion solution	Gibco	14170112	dissolved in Hank's balanced salt solution (HBSS-)
Decellularization solution	BioShop	CHA003	8 mM CHAPS
Decellularization solution	Sigma	E9884	25 mM EDTA
Decellularization solution	BioShop	SOD002	1 M NaCl
Decellularization solution	Gibco	14190-144	dissolved in PBS
Benzonase nuclease	Novagen	70664-3	90 U/ml Benzonase nuclease
Benzonase nuclease	Gibco	14190-144	diluted in PBS
Antimicrobial solution	Gibco	15140	200 U/ml penicillin streptomycin
Antimicrobial solution	Gibco	15290	25 μg/ml amphotericin B
Antimicrobial solution	Gibco	14190-144	diluted in PBS
Trypsinization	Gibco	12605-028	TrypLE
Serum free differentiation media (SFDM)	Gibco	IMDM 2440-053, F12 11765-054	3:1 ratio of IMDM and Ham’s modified F12 medium
Serum free differentiation media (SFDM)	Gibco	12587-010	B27 supplement (50x dilution)
Serum free differentiation media (SFDM)	Gibco	17502-048	N2 supplement (100x dilution)
Serum free differentiation media (SFDM)	Gibco	15260-037	0.05% (Fraction V) bovine serum albumin
Serum free differentiation media (SFDM)	Gibco	35050-061	200 mM Glutamax
Serum free differentiation media (SFDM)	Sigma	M6145	4 μM monothioglycerol
Serum free differentiation media (SFDM)	Sigma	A4403	0.05 mg/ml ascobic acid
Endoderm induction	R&D	338-AC/CF	Activin A
Antibodies
CDH1	BD Biosciences	610181	Mouse, non-conjugated, 1:100
C-KIT	BD Biosciences	558163	Rat, PE-Cy7, 1:100
CXCR4	BD Biosciences	558644	Rat, APC, 1:100
KRT5	Abcam	ab24647	Rabbit, non-conjugated, 1:1,000
NKX2-1	Abcam	ab76013	Rabbit, non-conjugated, 1:200
Laminin	Novus Biologicals	NB300-144	Rabbit, non-conjugated, 1:200
SCGB1A1	Santa Cruz	sc-9772	Goat, non-conjugated, 1:1,000
SOX2	R&D Systems	AF2018	Goat, non-conjugated, 1:400
TRP63	Santa Cruz	sc-8431	Mouse, non-conjugated, 1:200
TUBB4A	BioGenex	MU178-UC	Mouse, non-conjugated, 1:500
Goat IgG	Invitrogen	A-11055	Donkey, Alexa Fluor 488, 1:200
Mouse IgG	Invitrogen	A-21202	Donkey, Alexa Fluor 488, 1:200
Mouse IgG	Invitrogen	A-31571	Donkey, Alexa Fluor 647, 1:200
Rabbit IgG	Invitrogen	A-21206	Donkey, Alexa Fluor 488, 1:200
Rabbit IgG	Invitrogen	A-31573	Donkey, Alexa Fluor 647, 1:200
Other Materials
Low adherent plates	Nunc	Z721050	Low cell binding plates,  6 wells
Air-liquid interface membranes	Whatman	110614	Hydrophobic Nucleopore membrane, 8 μm pore size
Vibratome	Leica	VT1200S	Leica Vibratome
Tissue Adhesive	Ted Pella	10033	Pelco tissue adhesive