Interleukin-32α expression in human colonic subepithelial myofibroblasts.

Area of Science:

• Immunology
• Gastroenterology
• Cell Biology

Background:

• Interleukin-32 (IL-32) is a pro-inflammatory cytokine known to activate nuclear factor-kappa B (NF-κB).
• The expression and regulation of IL-32 isoforms, such as IL-32α, in specific cell types like colonic subepithelial myofibroblasts (SEMFs) remain to be fully elucidated.

Purpose of the Study:

• To investigate the expression of IL-32α in human colonic SEMFs.
• To determine the regulatory mechanisms, including signaling pathways, involved in IL-32α induction by inflammatory cytokines.

Main Methods:

• Isolation of SEMFs from normal human colon tissue.
• Analysis of IL-32α mRNA and protein expression using real-time PCR and Western blotting.
• Pharmacological inhibition of phosphatidylinositol 3-kinase (PI3K) and mitogen-activated protein kinase (MAPK) pathways, and blockade of NF-κB activation.

Main Results:

• IL-32α mRNA was constitutively expressed at low levels in SEMFs, with significant upregulation by IL-1β and TNF-α.
• IL-1β and TNF-α induced intracellular IL-32α protein accumulation, dependent on dose and time.
• PI3K and NF-κB signaling pathways were identified as critical mediators of IL-1β- and TNF-α-induced IL-32α mRNA expression, while MAPK pathways were not involved.

Conclusions:

• Human colonic SEMFs express IL-32α in response to inflammatory stimuli IL-1β and TNF-α.
• The induction of IL-32α expression in these cells is regulated by the PI3K and NF-κB signaling pathways.