Macrophage-Specific NF-κB Activation Dynamics Can Segregate Inflammatory Bowel Disease Patients

Area of Science:

• Immunology
• Molecular Biology
• Gastroenterology

Background:

• Inflammatory bowel disease (IBD) is heterogeneous, complicating treatment decisions.
• Nuclear Factor-kappa B (NF-κB) pathway activation is crucial in IBD pathogenesis.
• Patient-derived macrophages offer a model to study NF-κB dynamics in IBD.

Purpose of the Study:

• To develop and validate an in vitro assay to dynamically assess NF-κB activation in macrophages from IBD patients.
• To investigate if NF-κB activation patterns can distinguish between Crohn's disease (CD) and ulcerative colitis (UC) phenotypes.
• To explore the correlation between NF-κB activation, cytokine release, and clinical factors in IBD.

Main Methods:

• Lentiviral expression of NF-κB-regulated luciferase in patient-derived macrophages.
• Isolation of peripheral blood mononuclear cells (PBMCs) from frozen samples.
• Stimulation of macrophages and measurement of luciferase activity, cytokine concentrations, and p65 subunit localization.
• Clustering analysis of NF-κB response patterns.
• Correlation analysis with patient metadata including smoking status.

Main Results:

• Macrophage NF-κB activation patterns segregated IBD patients into three distinct clusters.
• Ulcerative colitis (UC) samples were primarily found in hypo-responsive clusters, while Crohn's disease (CD) samples were distributed across all clusters, with a higher proportion in hyper-responsive clusters.
• NF-κB activity correlated positively with released cytokine concentrations.
• CD patient macrophages showed increased p65 activation compared to controls; UC patient cells displayed shorter p65 nuclear localization duration.
• Smoking in CD patients correlated with hyper-activation of NF-κB.

Conclusions:

• Dynamic assessment of NF-κB activation in blood-derived macrophages can effectively differentiate IBD patient phenotypes.
• This approach holds potential for stratifying IBD patients for targeted therapy selection.
• NF-κB activation patterns may serve as a biomarker for disease phenotype and treatment response in IBD.