An Ex Vivo Gut Organ Culture System to Study Host-Microbiota Interactions

To study interactions between the host and the gut microbiota ex vivo, begin with a murine colon tissue free from specific gut-colonizing bacteria. Flush the tissue with a medium to remove the feces and transfer to a multi-well plate containing a suitable medium.

Concurrently, assemble the multi-well, ex vivo gut organ culture device. 

Each well of the device comprises two paired input and output ports — the first connecting to the colon lumen and the second providing a continuous supply of medium to the wells to maintain tissue viability.

Transfer the tissue to the device. Connect the colon's proximal and distal ends to the first pair of input and output ports. Start the luminal stimulant flow into the colon lumen and medium flow into the well.

The stimulant contains gut-colonizing bacteria that secrete mucus layer-degrading enzymes, allowing them to attach to underlying epithelial cells. This activates a signaling cascade that triggers resident dendritic cells to extend their dendrites between epithelial cells, capturing bacterial antigens and generating specific immune responses.

Consequently, naïve CD4+ T cells differentiate into Th17 cells.

The Th17 cells produce pro-inflammatory cytokines which activate other immune cells to combat the invading pathogens and maintain the integrity of the gut barrier.