1. Establishment of Gastric Organoid Culture
Note: This protocol can be used for the isolation of gastric glands from mouse or human tissue. It is advised to use tissue of approximately 1 cm². Human tissue can be obtained from gastric resections or biopsies.
2. Passage of Gastric Organoid Culture Before Microinjection.
Note: Every type of organoid culture has its own doubling time. Mouse intestinal as well as gastric cultures are usually split 1:5 every 5-7 days. Human intestinal cultures are split 1:5 every 10-12 days. Human gastric cultures are split 1:5 every 14 days. If initiated from single cells, human gastric organoids may also take 20 days to form properly. It is a good sign if budding structures surround the central lumen. In this protocol, organoids are split in 4 well plates for microinjection. Maintenance of organoids follows the same protocol, but can use any other cell culture plate, such as standard 24 well cell culture plates.
3. Microinjection of Organoid Culture.
Note: This protocol can be used to microinject bacteria into organoids. It may be helpful to start the injection with organoids that are more permissive to microinjection. For example, mouse gastric organoids can grow into very large cystic organoids that are easy to target.
This protocol allows isolation of gastric glands (Figure 2). Glands are seeded into basement matrix, which solidifies as drop within a well, providing a 3 dimensional framework rich in laminin and collagen to allow the glands grow into organoids (Figure 3). Organoids typically start as small cysts and within 12-16 days, they expand into spheres with a diameter of 50-300 µm (Figure 4). Some organoids will stay cystic, some will develop small buddings. The latter is usually a sign of a healthy growing culture. In this protocol one well of a 24 well plate is used for 100 glands, 50 µl of basement matrix and 500 µl of medium. However, this can be up- or downscaled.
The success of the microinjection can readily be observed under the stereomicroscope as the cloudy, bacterial solution fills the organoid (Figure 5). After adequate incubation time, organoids can be processed for any analysis method desired. For example, organoids can be embedded in paraffin, sections can be cut and stained using standard immunohistochemistry techniques. Microscopic analysis of immunostained organoids demonstrate successful injection of the bacteria (Figure 6).
Figure 1. Image of Pasteur pipette used for passage of organoids. In each panel, the upper pipette is before, the lower pipette after narrowing by fire. Scale in upper and right panels is cm and mm. Please click here to view a larger version of this figure.
Figure 2. Representative image of isolated human gastric glands. Scale bar 100 µm. Please click here to view a larger version of this figure.
Figure 3. Scheme of wells and representative image of human gastric organoids. Isolated human gastric glands were dispensed in basement matrix and placed as drops into wells of a 24 well plate. Lower left: Overview of a representative well 11 days after seeding. Lower right: Enlargement of the indicated area. Scale bar 100 µm. Gastric mouse organoids expand faster18. Please click here to view a larger version of this figure.
Figure 4. Typical growth of human gastric organoids. Glands were seeded into basement matrix and images of the same organoid were taken over a period of 12 days. Scale bar 100 µm Please click here to view a larger version of this figure.
Figure 5. Microinjection of gastric organoids. Stereoscope images of a gastric organoid before (left) and during (right) microinjection of bacteria into the lumen. Bacteria are visible as cloud inside the organoid. Scale bar 200 µm. Please click here to view a larger version of this figure.
Figure 6. Immunostained organoids. Human gastric organoids were microinjected with H. pylori. After 4 hr, organoids were fixed in paraformaldehyde and embedded in paraffin. Sections were stained using antibodies targeting the bacterial protein Cytotoxicity associated gene A (CagA) according to standard histology methods25. Upper left: Image of a representative organoid. Lower panel: Higher magnification of the boxed area. Upper right: Higher magnification of the boxed area with a single bacterium close to the epithelial cells. Please click here to view a larger version of this figure.
Medium | |||
HEPES | Invitrogen | 15630-056 | |
Advanced DMEM/F12 | Invitrogen | 12634-028 | |
Matrigel, GFR, phenol free | BD | 356231 | |
GlutaMAX | Invitrogen | 35050-079 | Stock concentration 200 mM, final concentration 2 mM |
B27 | Invitrogen | 17504-044 | Stock concentration 50 x, final concentration 1x |
N-Acetylcysteine | Sigma-Aldrich | A9165-5G | Stock concentration 500 mM, final concentration 1 mM |
Murine recombinant EGF | Invitrogen | PMG8043 | Stock concentration 500 µg/mL, final concentration 50 ng/mL |
Human recombinant FGF10 | Peprotech | 100-26 | Stock concentration 100 µg/mL, final concentration 200 ng/mL |
TGFβi A-83-01 | Tocris | 2939 | Stock concentration 500 µM, final concentration 2 µM |
Nicotinamide | Sigma-Aldrich | N0636 | Stock concentration 1 M, final concentration 10 mM |
[Leu15]-Gastrin | Sigma-Aldrich | G9145 | Stock concentration 100 µM, final concentration 1 nM |
RHOKi Y-27632 | Sigma-Aldrich | Y0503 | Stock concentration 10 mM, final concentration 10 µM |
Wnt3A conditioned medium | Stable cell line generated in the Clevers Lab. Final concentration 50%. Cells can be obtained from Hans Clevers. | ||
R-spondin1 conditioned medium | Stable cell line generated in the Kuo Lab. Final concentration 10%. Cell line can be obtained from Calvin Kuo, Stanford. | ||
Noggin conditioned medium | Stable cell line generated in the Clevers Lab. Final concentration 10%. Cells can be obtained from Hans Clevers. | ||
R-spondin3 | R&D | 3500-RS/CF | Alternative source for R-spondin. This has been tested on human intestine organoids (1 µg/mL), but not yet on gastric organoids. |
Noggin | Peprotech | 120-10 | Alternative source for noggin. This has been tested on human intestine organoids (100 ng/mL), but not yet on gastric organoids. |
TrypLE express | Life Technologies | 12605036 | Enzymatic dissociation solution |
CoolCell® Alcohol-Free Cell Freezing Containers | biocision | BCS-405 | |
Recovery Cell Culture Freezing Medium | Invitrogen | 12648-010 | |
Antibiotics | |||
Primocin | Invivogen | ant-pm-1 | An antibiotics composition agains bacteria and fungi. It is helpful after initiation of a culture. For long term culture you can switch to other antibiotics or none. |
Penicillin/Streptomycin | Invitrogen | 15140-122 | Stock concentration 10000/10000 U/mL, final concentration 100/100 U/mL. Can be used alternatively to Primocin in long term culture. |
기타 | |||
Tweezers | Neolabs | 2-1033 | Tweezers with fine tips are helpful for the removal of muscle layer from the tissue. |
4 Well Multidishes | Thermo Scientific | 144444 | You can use other Multidishes. These were particularly helpful for microinjections because they have a low outer rim and allow more mobility for the manipulator. |
Micromanipulator | Narishige | M-152 | |
Microinjector | Narishige | IM-5B | |
Stereomicroscope | Leica | MZ75 | |
Workbench | Clean Air | Custom made to fit the stereomicroscope in ML2 condition | |
Cappillaries | Harvard Apparatus | GC100T-10 | 1 mm outer diameter, 0,78 mm inner diameter. |
Micropipette Puller | Sutter Instruments | Flaming Brown Micropipette Puller | |
anti Cag A antibody | Santa Cruz | sc-25766 |
Recently infection biologists have employed stem cell derived cultures to answer the need for new and better models to study host-pathogen interactions. Three cellular sources have been used: Embryonic stem cells (ESC), induced pluripotent stem cells (iPSC) or adult stem cells. Here, culture of mouse and human gastric organoids derived from adult stem cells is described and used for infection with the gastric pathogen Helicobacter pylori. Human gastric glands are isolated from resection material, seeded in a basement matrix and embedded in medium containing growth factors epidermal growth factor (EGF), R-spondin, Noggin, Wnt, fibroblast growth factor (FGF) 10, gastrin and transforming growth factor (TGF) beta inhibitor. In these conditions, gastric glands grow into 3-dimensional organoids containing 4 lineages of the stomach. The organoids expand indefinitely and can be frozen and thawed similarly as cell lines. For infection studies, bacteria are microinjected into the lumen of the organoids. Infected organoids are processed for imaging. The described methods can be adapted to other organoids and infections with other bacteria, viruses or parasites. This allows the study of infection-induced changes in primary cells.
Recently infection biologists have employed stem cell derived cultures to answer the need for new and better models to study host-pathogen interactions. Three cellular sources have been used: Embryonic stem cells (ESC), induced pluripotent stem cells (iPSC) or adult stem cells. Here, culture of mouse and human gastric organoids derived from adult stem cells is described and used for infection with the gastric pathogen Helicobacter pylori. Human gastric glands are isolated from resection material, seeded in a basement matrix and embedded in medium containing growth factors epidermal growth factor (EGF), R-spondin, Noggin, Wnt, fibroblast growth factor (FGF) 10, gastrin and transforming growth factor (TGF) beta inhibitor. In these conditions, gastric glands grow into 3-dimensional organoids containing 4 lineages of the stomach. The organoids expand indefinitely and can be frozen and thawed similarly as cell lines. For infection studies, bacteria are microinjected into the lumen of the organoids. Infected organoids are processed for imaging. The described methods can be adapted to other organoids and infections with other bacteria, viruses or parasites. This allows the study of infection-induced changes in primary cells.
Recently infection biologists have employed stem cell derived cultures to answer the need for new and better models to study host-pathogen interactions. Three cellular sources have been used: Embryonic stem cells (ESC), induced pluripotent stem cells (iPSC) or adult stem cells. Here, culture of mouse and human gastric organoids derived from adult stem cells is described and used for infection with the gastric pathogen Helicobacter pylori. Human gastric glands are isolated from resection material, seeded in a basement matrix and embedded in medium containing growth factors epidermal growth factor (EGF), R-spondin, Noggin, Wnt, fibroblast growth factor (FGF) 10, gastrin and transforming growth factor (TGF) beta inhibitor. In these conditions, gastric glands grow into 3-dimensional organoids containing 4 lineages of the stomach. The organoids expand indefinitely and can be frozen and thawed similarly as cell lines. For infection studies, bacteria are microinjected into the lumen of the organoids. Infected organoids are processed for imaging. The described methods can be adapted to other organoids and infections with other bacteria, viruses or parasites. This allows the study of infection-induced changes in primary cells.