Actin networks modulate heterogeneous NF-κB dynamics in response to TNFα

Area of Science:

• Cell Biology
• Molecular Biology
• Cancer Research

Background:

• The transcription factor RELA is crucial for immune and stress responses.
• RELA is frequently upregulated in pancreatic ductal adenocarcinoma (PDAC) tumors.
• Understanding RELA dynamics in PDAC is vital for therapeutic strategies.

Purpose of the Study:

• To investigate the dynamics of endogenous RELA-GFP in PDAC cell lines using live single-cell imaging.
• To explore the relationship between F-actin dynamics and RELA heterogeneity in PDAC.
• To elucidate the regulatory mechanisms of RELA activation by TNFα in PDAC.

Main Methods:

• Live single-cell imaging of RELA-GFP dynamics.
• Bayesian analysis of single-cell datasets.
• RNA-sequencing (RNA-seq) for gene expression analysis.
• siRNA-mediated gene depletion.
• Characterization of NF-κB/IκB protein interactions.

Main Results:

• TNFα stimulation caused rapid, sustained nuclear translocation of RELA in PDAC cells.
• RELA heterogeneity was predicted to depend on F-actin dynamics.
• RELA upregulated actin regulators NUAK2 and ARHGAP31, forming a negative feedback loop.
• NF-κB/IκB proteins interact with RELA in PDAC cells.

Conclusions:

• A novel interdependence exists between the F-actin network and NF-κB pathway signaling in PDAC.
• RELA translocation dynamics are regulated by a feedback loop involving actin regulators.
• These findings offer insights into PDAC pathogenesis and potential therapeutic targets.