Gap junctional communication between murine macrophages and intestinal epithelial cell lines

Area of Science:

• Cell Biology
• Immunology
• Gastroenterology

Background:

• Inflammatory cells infiltrate the submucosa during intestinal inflammation.
• These cells are positioned near intestinal epithelial cell (IEC) basolateral membranes.
• Direct regulation of IEC function by inflammatory cells is possible.

Purpose of the Study:

• To determine if macrophages (M phi) are coupled by gap junctions to IEC lines.
• To investigate the mechanism of communication between macrophages and IECs.

Main Methods:

• Utilized flow cytometry to detect bi-directional dye transfer (calcein) between macrophages and IECs.
• Examined homocellular and heterocellular dye transfer in co-cultures.
• Assessed calcium wave propagation and electron microscopy for membrane apposition.

Main Results:

• Demonstrated bi-directional transfer of the fluorescent dye calcein between IECs and M phi.
• Showed that dye transfer and cell adhesion were dependent on IEC-M phi interaction and inhibited by heptanol.
• Observed propagation of calcium waves and close membrane appositions, indicative of gap junction formation.

Conclusions:

• Intestinal epithelial cells and macrophages are coupled by gap junctions.
• Gap junctional communication may be a mechanism for inflammatory cells to regulate IEC function.
• These findings offer insights into cell-to-cell communication in intestinal inflammation.