Efficient Differentiation of Pluripotent Stem Cells to NKX6-1+ Pancreatic Progenitors

Summary

Here we describe a 4-stage protocol to differentiate human embryonic stem cells to NKX6-1⁺ pancreatic progenitors in vitro. This protocol can be applied to a variety of human pluripotent stem cell lines.

Abstract

Pluripotent stem cells have the ability to self renew and differentiate to multiple lineages, making them an attractive source for the generation of pancreatic progenitor cells that can be used for the study of and future treatment of diabetes. This article outlines a four-stage differentiation protocol designed to generate pancreatic progenitor cells from human embryonic stem cells (hESCs). This protocol can be applied to a number of human pluripotent stem cell (hPSC) lines. The approach taken to generate pancreatic progenitor cells is to differentiate hESCs to accurately model key stages of pancreatic development. This begins with the induction of the definitive endoderm, which is achieved by culturing the cells in the presence of Activin A, basic Fibroblast Growth Factor (bFGF) and CHIR990210. Further differentiation and patterning with Fibroblast Growth Factor 10 (FGF10) and Dorsomorphin generates cells resembling the posterior foregut. The addition of Retinoic Acid, NOGGIN, SANT-1 and FGF10 differentiates posterior foregut cells into cells characteristic of pancreatic endoderm. Finally, the combination of Epidermal Growth Factor (EGF), Nicotinamide and NOGGIN leads to the efficient generation of PDX1⁺/NKX6-1⁺ cells. Flow cytometry is performed to confirm the expression of specific markers at key stages of pancreatic development. The PDX1⁺/NKX6-1⁺ pancreatic progenitors at the end of stage 4 are capable of generating mature β cells upon transplantation into immunodeficient mice and can be further differentiated to generate insulin-producing cells in vitro. Thus, the efficient generation of PDX1⁺/NKX6-1⁺ pancreatic progenitors, as demonstrated in this protocol, is of great importance as it provides a platform to study human pancreatic development in vitro and provides a source of cells with the potential of differentiating to β cells that could eventually be used for the treatment of diabetes.

Introduction

The prevalence of diabetes is increasing and according to the Canadian Diabetes Association, it is estimated that over 11 million individuals in Canada are diabetic or prediabetic, with 5-10% of these individuals having type 1 diabetes (T1D)¹. T1D is an autoimmune disease that is caused by the destruction of the insulin producing β cells that are located within the Islets of Langerhans. Currently, individuals living with T1D require exogenous sources of insulin². Despite advances in insulin therapy, T1D patients continue to have a difficult time regulating their blood glucose levels and continue to suffer both hypo-....

Protocol

1. Preparation of Solutions and Media

NOTE: Prepare all media for cell culture in a sterile environment. Media has to be made and used immediately. Reagent details are provided in the Materials Table.

1. Differentiation Media
   1. Prepare Day 0 Differentiation Media: RPMI Medium with 1% Glutamine, 2 µM CHIR 99021, 100 ng/ml Activin A, 10⁴ M MTG.
   2. Prepare Day 1-2 Differentiation Media: RPMI Medium with 1% Glutamine, 100 ng/ml Activin A, 10⁴ M MTG, 5 ng/ml bFGF, 50 µg/ml Ascorbic Acid.
   3. Prepare Day 3-5 Differentiation Media: RPMI Medium with ....

Results

Efficient generation of pancreatic progenitors relies on the proper growth and maintenance of undifferentiated cells followed by the precise addition of specific signaling molecules during the differentiation protocol, as illustrated in the schematic in Figure 1A. On day 0, undifferentiated cells should be 80-95% confluent and colonies should have defined edges (Figure 1A). During Stage 1, the media will likely appear cloudy since cell death is quite comm.......

Discussion

Successfully generating NKX6-1⁺ pancreatic progenitors from hPSCs in vitro relies on the use of high quality cultures of hPSCs and directed differentiation involving the precise regulation of specific signaling pathways that govern key developmental stages during pancreatic development. Although this protocol can be used to induce robust expression of NKX6-1 across a variety of hPSC lines as previously shown³, to ensure efficient NKX6-1 generation the following considerations s.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Media and cytokines
1-Thioglycerol (MTG)	Sigma	M6145
Activin A	R&D	338-AC/CF
Ascorbic Acid	Sigma	A4544
B-27 Supplement	Life Technologies	12587-010
BD Cytofix/Cytoperm Buffer	BD Bioscience	554722
BD Perm/Wash buffer, 1x	BD Bioscience	554723
bFGF	R&D	233-FB
CHIR990210	Tocris	4423a
Dulbecco’s Modified Eagle Medium (DMEM)	Life Technologies	11995
DNase I	VWR	80510-412
Dorsomorphin	Sigma	P5499
EGF	R&D	236-EG
Fetal Bovine Serum (FBS)	Wisent	88150
FGF10	R&D	345-FG
Gelatin from porcine skin	Sigma	G1890
Glutamine	Life Technologies	25030
Nicotinamide	Sigma	NO636
NOGGIN	R&D	3344-NG
Penicillin/Streptomycin	Life Technologies	15070-063
Retinoic acid	Sigma	R2625
RPMI Medium 1640	Life Technologies	11875
SANT-1	Tocris	1974
TrypLE Express Enzyme (1x), phenol red	Life Technologies	12605-010
Name	Company	Catalogue Number	Comments
Antibodies for flow cytometry (working dilutions)
CD117 PE (1:100)	Life Technologies	CD11705
CXCR4 APC (1:50)	BD  Bioscience	551966
Donkey Anti-Mouse IgG (H+L), Alexa Fluor 647 conjugate (1:400)	Life Technologies	A-31571
Donkey Anti-Goat IgG (H+L), Alexa Fluor 488 (1:400)	Jackson ImmunoResearch Laboratories Inc.	705-546-147
Isotype Control Mouse IgG	Jackson ImmunoResearch Laboratories Inc.	015-000-003
Isotype Control Goat IgG	R&D	AB-108-C
NKX6-1 (1:2,000)	DSHB	F55A10
PDX1 (1:100)	R&D	AF2419