An Intestinal Gut Organ Culture System for Analyzing Host-Microbiota Interactions

Summary

This article presents a unique method for analyzing host-microbiome interactions using a novel gut organ culture system for ex vivo experiments.

Abstract

The structure of the gut tissue facilitates close and mutualistic interactions between the host and the gut microbiota. These cross-talks are crucial for maintaining local and systemic homeostasis; changes to gut microbiota composition (dysbiosis) associate with a wide array of human diseases. Methods for dissecting host-microbiota interactions encompass an inherent tradeoff among preservation of physiological tissue structure (when using in vivo animal models) and the level of control over the experiment factors (as in simple in vitro cell culture systems). To address this tradeoff, Yissachar et al. recently developed an intestinal organ culture system. The system preserves a naive colon tissue construction and cellular mechanisms and it also permits tight experimental control, facilitating experimentations that cannot be readily performed in vivo. It is optimal for dissecting short-term responses of various gut components (such as epithelial, immunological and neuronal elements) to luminal perturbations (including anaerobic or aerobic microbes, whole microbiota samples from mice or humans, drugs and metabolites). Here, we present a detailed description of an optimized protocol for organ culture of multiple gut fragments using a custom-made gut culture device. Host responses to luminal perturbations can be visualized by immunofluorescence staining of tissue sections or whole-mount tissue fragments, fluorescence in-situ hybridization (FISH), or time-lapse imaging. This system supports a wide array of readouts, including next-generation sequencing, flow cytometry, and various cellular and biochemical assays. Overall, this three-dimensional organ culture system supports the culture of large, intact intestinal tissues and has broad applications for high-resolution analysis and visualization of host-microbiota interactions in the local gut environment.

Introduction

The intestine is a highly complex organ containing a wide range of cell types (epithelial cells, immune system cells, neurons, and more) organized in a particular structure that allows cells to interact and communicate with one another and with the luminal content (microbiota, food, etc.)¹. Currently, the research toolbox available for analyzing host-microbiota interactions includes in vitro cell cultures and in vivo animal models². In vivo animal models provide a physiological tissue construction³ but with poor experimental control and limited ability to manipulate the ....

Protocol

This protocol follows the animal care guidelines approved by the ethics committee for animal welfare.

1. Experiment preparation

1. Fabrication of the gut organ culture device (3 days)
   1. Using a 3D printer, print the reusable plastic molds for the organ culture device (the device has 6 wells, with 24 small and large holes, and for the device cover lid) (3D files attached).
      NOTE: These plastic molds may be used for fabrication of numerous devices.
   2. Insert the.......

Discussion

This article describe an optimized protocol for ex vivo gut organ cultures that Yissachar et al. have recently developed (published⁹ and unpublished data). The gut organ culture system supports multiplexed culture of intact intestinal fragments while maintaining luminal flow. It provides full control over the intra- and extra-luminal environment (including stimulation dose, exposure time and flow rate) and preserves the naïve intestinal tissue structure and its cellular complexity

Materials

Name	Company	Catalog Number	Comments
Device
18 Gauge Blunt Needle	Mcmaster	75165a754
22 Gauge Blunt Needle	Mcmaster	75165a758
All Purpose Adhesive Selant 100% Silicone	DAP	688
Cubic Vacuum Desiccator VDC-21+ 2 Shelves		AAAD4021
Glass Slide 1 mm Thick	Corning	2947-75X50
Mini Incubator im-10		AAH24315K
MPC 301E Vacuum PUMP		VI-412711
Plastic Quick Turn Tube Coupling Plugs	Mcmaster	51525k121
plastic Quick Turn Tube Coupling Sockets	Mcmaster	52525k211
Sylgard 184 Silicone Elastomer	Dow		Polydimethylsiloxane, PDMS
Tubing	Mcmaster	6516t11
Zortrax M200	Zortrax		Zortrax Z-SUITE, Autodesk Fusion 360
Zortrax M200 Materials: z-ultrat	Zortrax
Medium
B27 Supplement (50x), Serum Free	Thermo Fisher Scientific	17504044
HEPES Buffer (1M)	Thermo Fisher Scientific	15630056
Iscove's Mod Dulbecco's Medium With Phenol Red (1x)	Thermo Fisher Scientific	12440061
Knock-Out Serum	Thermo Fisher Scientific	10828028
N2 Supplement (100x)	Thermo Fisher Scientific	A1370701
Non Essential Amino Acid (100x)	Thermo Fisher Scientific	11140035
Surgical Tools
Large Scissors	Aseltech	11-00-10
Sharp Forceps	F.S.T	11297-10
Silk Braided Surgical Thread	SMI	8010G
Straight Scissors	F.S.T	14091-09
Thin Forceps	F.S.T	11051-10
Organ System
0.1 µm Filter	Life Gene
0.22 µm Filter	Life Gene
5 mL Luer Lock Syringe	B-D	309649
Greenough Stereo Microscope	ZEISS	Stemi 305
Recirculating Precision Air Heater "CUBE"		CUBE-2-LIS
Syringe Pump	new era pump systems inc	nep-ne-1600-em