Intercellular interactions between mast cells and fibroblasts promote pro-inflammatory signaling

Area of Science:

• Immunology
• Cell Biology
• Inflammation Research

Background:

• Mechanisms underlying acute exacerbations in chronic inflammatory diseases remain unclear.
• Interleukin-8 (IL-8) is a crucial chemoattractant for neutrophils in acute inflammatory lesions.

Purpose of the Study:

• To investigate the role of fibroblast-mast cell interactions in short-term IL-8 release.
• To elucidate the cellular and molecular mechanisms driving IL-8 secretion in co-cultures.

Main Methods:

• Co-culture of human gingival fibroblasts with human mast cells (HMC).
• Quantification of IL-8 concentration using ELISA.
• Assessment of intercellular communication via calcein-dye transfer and gap junction inhibition (β-glycyrrhetinic acid).

Main Results:

• HMC-fibroblast co-cultures exhibited >8-fold higher IL-8 secretion compared to individual cell types.
• IL-8 secretion required intercellular contact, was serum-enhanced, and blocked by gap junction inhibitors.
• Hyaluronic acid on fibroblasts promoted IL-8 secretion; mast cell activation significantly increased fibroblast IL-8 production.

Conclusions:

• Mast cells adhere to fibroblasts, promoting IL-8 secretion through gap junction communication.
• This interaction enhances neutrophil chemotaxis, contributing to inflammatory responses.
• Fibroblast-mast cell crosstalk is a significant pathway for initiating acute inflammatory responses.