Quantifying NF-κB Activation by Flow Cytometry of IκBα Degradation

Area of Science:

• Immunology
• Cellular Biology
• Molecular Biology

Background:

• Nuclear factor-κB (NF-κB) is a key pro-inflammatory transcription factor central to immune responses.
• Directly measuring active, nuclear NF-κB via flow cytometry is challenging due to antibody limitations.
• Assessing NF-κB activation is critical for understanding inflammatory processes and developing targeted therapies.

Purpose of the Study:

• To develop and validate a flow cytometry assay for quantifying NF-κB activation.
• To indirectly measure NF-κB activation by assessing the degradation of its inhibitor, IκBα.
• To provide a reproducible method for medium-to-high-throughput analysis of NF-κB activity in immune cells.

Main Methods:

• A flow cytometry protocol was established to quantify the intracellular levels of IκBα.
• The assay measures the decrease in IκBα as an indicator of NF-κB pathway activation.
• The protocol was validated using human primary regulatory T cells stimulated with TNFR2 agonists.

Main Results:

• The developed flow cytometry assay successfully detected IκBα degradation in response to inflammatory stimuli.
• The assay demonstrated utility in human primary regulatory T cells, T cells, and THP-1 cell-derived macrophages.
• The protocol provides a reliable method for assessing NF-κB activation across different immune cell types.

Conclusions:

• This protocol offers a robust and reproducible method for measuring NF-κB activation via IκBα degradation using flow cytometry.
• The assay is adaptable for various immune cells and inflammatory triggers, facilitating broader research applications.
• This technique enhances the ability to study inflammatory responses and screen potential immunomodulatory agents.