The Ex Vivo Culture and Pattern Recognition Receptor Stimulation of Mouse Intestinal Organoids

Summary

Here, a protocol to harvest, maintain, and treat mouse small intestinal organoids with pathogen associated molecular patterns (PAMPs) and Listeria monocytogenes is described, as well as emphasis on gene expression and proper normalization techniques for protein.

Abstract

Primary intestinal organoids are a valuable model system that has the potential to significantly impact the field of mucosal immunology. However, the complexities of the organoid growth characteristics carry significant caveats for the investigator. Specifically, the growth patterns of each individual organoid are highly variable and create a heterogeneous population of epithelial cells in culture. With such caveats, common tissue culture practices cannot be simply applied to the organoid system due to the complexity of the cellular structure. Counting and plating based solely on cell number, which is common for individually separated cells, such as cell lines, is not a reliable method for organoids unless some normalization technique is applied. Normalizing to total protein content is made complex due to the resident protein matrix. These characteristics in terms of cell number, shape and cell type should be taken into consideration when evaluating secreted contents from the organoid mass. This protocol has been generated to outline a simple procedure to culture and treat small intestinal organoids with microbial pathogens and pathogen associated molecular patterns (PAMPs). It also emphasizes the normalization techniques that should be applied when protein analysis are conducted after such a challenge.

Introduction

The ability to harvest and culture primary organoids have been described for small intestine, colon, pancreas, liver and brain and are exciting advances germane to understanding a more physiologically representative phenomena for tissue biology^1-5. The first methods describing the culture and maintenance of small intestinal organoids was reported by Sato et al. out of the lab of Hans Clevers¹. Prior to this method, harvesting and culture of primary intestinal epithelial cells proved to be limited and ineffective in sustaining epithelial cell growth. Methods included dissociation of tissue via incubation with enzymes, such as collagenase ....

Protocol

All research was approved and conducted under Virginia Tech IACUC guidelines

1. Prepare R-Spondin1 Conditioned Media From HEK293T-Rspo1 Cell Line

1. Generation of HEK293T-Rspondin1 cells has been previously described¹⁰. Seed HEK293T-Rspondin1 secreting cells at 5-10% confluency, approximately 8 x 10⁵-1.7 x 10⁶ cells, in a T-175 flask with 40 ml of 1x Dulbecco's Modified Eagle Medium (DMEM) + 10% Fetal Bovine Serum (FBS) as the growth media, and incubate at 37 °C + 5% CO₂.  
   NOTE: The growth media for the HEK293T-Rspondin1 secreting cells will serve as R-spondin1 conditioned media. R-spond....

Results

When following this protocol to cultivate intestinal organoids, characteristic sphere shaped organoids will be present after harvesting. The addition of R-spondin1 conditioned media daily will initiate the growth and budding of the organoids. The growth of organoids is shown in Figure 1A-F, and is representative of intestinal organoids on days 1, 2, 4, 5, 6 and day 14. Figure 1F represents the non-homogeneous growth chara.......

Discussion

The culture and maintenance of intestinal organoids is a procedure that can be mastered by any individual with adequate tissue culture technique. There are subtleties in passaging when compared to growing cells in a more conventional monolayer, but these subtleties are not difficult to overcome. The critical steps of this method involve being able to grow the organoids to a high enough density for optimal seeding. Experiments must be scaled down with organoids as large seeding densities that can commonly be achieved with.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Fetal Bovine Serum (FBS)	Atlanta Biologicals	S11050	(Section 1,3,6) Or equivalent brand
Sorvall Legend XTR Centrifuge	Thermo		(Section 1,3)
DMEM	GE Healthcare	Sh30243.01	(Section 1,6) For Caco-2 and HEK293 Rspondin1 cells
HEK293T-Rspondin1 secreting cell line			(Section 1) Described and modified from Kim, K.A. et al. Lentiviral particles contained RSPO1(NM_138683) ORF cDNA cloned into a pReceiver-Lv105 backbone custom ordered and purchased from GeneCopoeia.
50 ml conical tube	Falcon	352070	(Section 1) Or equivalent brand
T-175 Flask	Corning	431079	(Section 1) Or equivalent brand
Protein Matrix	Corning	356231	(Section 2,3,4,5,6) Matrigel Growth Factor Reduced
HyClone Dulbecco's (DPBS)	GE Healthcare	SH30264.01	(Section 2,3)
DMEM/F12	Life Technologies	12634-010	(Section 2,3) Advanced DMEM/F12
Corning 24 Well TC Plates	Corning	3524	(Section 2)
N2 Supplement 100x	Life Technologies	17502-048	(Section 2)
B27 without vitamin A 50x	Life Technologies	12587-010	(Section 2)
Trizol	Life Technologies	15596-026	(Section 2)
Glutamine Supplement (Glutamax)	Life Technologies	35050-061	(Section 2) Can Combine with Advanced DMEM/ F12
HEPES (1 M)	Life Technologies	15630-080	(Section 2) Can Combine with Advanced DMEM/ F12
10ml Serological Pipet	Falcon	357551	(Section 2) Or equivalent brand
Murine Noggin	Peprotech	250-38	(Section 2) Stock = 100 mg/ml
N-Acetyl-L-cysteine	Sigma-Aldrich	A9165	(Section 2) Stock = 1M
Recombinant Mouse EGF	Biolegend	585608	(Section 2) Stock = 500 mg/ml
Rocker Variable	Bioexpres		(Section 3)
dissecting scissors			(Section 3)
forceps			(Section 3)
glass slides			(Section 3)
dissecting tweezers			(Section 3)
25 ml Serological Pipet	Falcon		(Section 3)
EDTA	Sigma-Aldrich	SLBB9821	(Section 3) 0.5M or alternative TC grade EDTA
Sterile Petri Dish 100mm x 15mm	Fisher	FB0875712	(Section 3) Or equal sized TC dish
1ml Syringe	Becton Dickinson	309659	(Section 4)
Precision Glide Needle	Becton Dickinson	305120	(Section 4) 23G x 1 1/4 (0.6mm x 30mm)
Flagellin from Bacillus subtilis	Invivogen	tlrl-bsfla	(Section 5,6)
Listeria monocytogenes	ATCC	19115	(Section 5,6) (Murray et al.)
Hemocytometer	Sigma-Aldrich	Z359629-1EA	(Section 5,6)Or equivalent brand
BBL Brain Heart Infusion Agar	Becton Dickinson	211065	(Section 5)
Bacto Brain Heart Infusion	Becton Dickinson	237500	(Section 5)
Caco-2	ATCC	HTB-37	(Section 6)
Trypsin	gibco	25200056	(section 6)
Methanol	Fisher	A412-4	(Section 6)
SpectraMax M5	Molecuar Devices		(Section 6)
96 Well Assay Plate	Corning	3603	(Section 6) Black Plate, Clear Bottom TC treated
Nuclear Staining Dye	Life Technologies	H1399	(section 6) Hoechst 33342
T-75 Flask	Corning	430641	(Section 6) Or equivalent brand
15 ml conical tube	Falcon	352096	(Section1,3) Or equivalent brand
1.7 ml polypropylene tube	Bioexpress	C-3262-1	Or equivalent brand
Quick-RNA MiniPrep	Zymo Research	R1054	Or equivalent brand
TNF-alpha	Applied Biosystems	Mm 00443260_g1	Taqman gene expression assay kit
IL-6	Applied Biosystems	(Mm 00446190_m1	Taqman gene expression assay kit
IL-1beta	Applied Biosystems	Mm 00434228_m1	Taqman gene expression assay kit
IL-18	Applied Biosystems	Mm 00434225_m1	Taqman gene expression assay kit
18s	Applied Biosystems	Hs 99999901_s1	Taqman gene expression assay kit
7500 Fast Real Time PCR System	Applied Biosystems
Nexus gradient Mastercycler	Eppendorf
TaqMan Fast Universal PCR Master Mix	Life Technologies	4352042
High Capacity cDNA Reverse Transcription Kit	Life Technologies/Applied Biosystems	4368814
Fast Optical 96-Well Reaction Plate, 0.1 mL	Life Technologies/Applied Biosystems	4346907
Recombinant Mouse R-Spondin 1 Protein	R&D Systems	3474-RS-050	500 ng/ml
chloroform	Sigma-Aldrich	C7559