Spatial Single Cell Profiling Using Imaging Mass Cytometry: Inflammatory Versus Penetrating Crohn's Disease

Area of Science:

• Immunology
• Gastroenterology
• Cell Biology

Background:

• Fistula formation is a significant complication in Crohn's disease (CD).
• The precise role of immune cells in CD fistula pathogenesis is not fully understood.
• Comparing immune cell compartments in CD fistulas versus CD colitis is crucial for understanding disease mechanisms.

Purpose of the Study:

• To compare the immune cell compartment in Crohn's disease (CD) fistulas with CD colitis and non-inflamed controls.
• To elucidate the spatial context and interactions of immune cells within CD fistulas.
• To identify potential therapeutic targets for CD complications.

Main Methods:

• Utilized a 36-marker panel for imaging mass cytometry (IMC) on paraffin-embedded tissue.
• Analyzed samples from CD fistula tracts (n=11), CD colitis (n=10), and controls (n=12).
• Employed computational methods for cell segmentation, clustering, and spatial analysis, complemented by multiplex immunofluorescence.

Main Results:

• CD fistulas exhibited increased neutrophils, effector cytotoxic T cells, and inflammatory macrophages, with decreased regulatory T cells compared to controls and colitis.
• Neutrophils in CD fistulas showed higher expression of matrix metalloproteinase 9 (MMP9), linked to extracellular matrix remodeling.
• Spatial analysis revealed a strong association between MMP9+ neutrophils and effector cytotoxic T cells in both CD fistulas and colitis.

Conclusions:

• This study provides the first highly multiplexed single-cell analysis of the immune cell compartment in CD fistulas.
• It links immune cell dynamics, particularly MMP9+ neutrophils, to extracellular matrix remodeling in CD fistulas.
• Findings offer insights into cellular interactions and potential therapeutic strategies for CD complications.