What question did this study set out to answer?

To investigate the role of fibroblasts in mucin synthesis by airway epithelial cells derived from COPD patients.

April 11, 2026

Fibroblast crosstalk promotes mucin synthesis by COPD-derived airway epithelial cells

Key Points

To investigate the role of fibroblasts in mucin synthesis by airway epithelial cells derived from COPD patients.
Cultured primary bronchial epithelial cells from COPD patients at air-liquid interface with and without fibroblasts.
Assessed mRNA expression of mucociliary markers and inflammatory cytokines using qPCR.
Measured mucin release and cytokine levels in supernatant by ELISA.
Performed immunohistochemical staining on transwell inserts.
Co-cultured epithelial cells with fibroblasts and treated with IL-6 neutralizing antibody.
PBECs co-cultured with fibroblasts showed increased expression of MUC5B mRNA.
MUC5AC and MUC5B protein levels were higher in fibroblast co-cultures.
Fibroblasts exhibited elevated IL-6 expression when co-cultured with epithelial cells.
Blocking IL-6 reduced the increase in MUC5B expression in Calu-3 cells.
Findings indicate enhanced mucous cell differentiation due to fibroblast interactions.

Abstract

Chronic mucus hypersecretion (CMH) is a common feature of chronic obstructive pulmonary disease (COPD). One of the major factors contributing to CMH is excessive mucin release by the airway epithelium. We hypothesized that fibroblasts support mucociliary differentiation and promote epithelial mucin release. Primary bronchial epithelial cells (PBECs) from COPD patients with CMH were cultured at air-liquid interface (ALI) with and without primary airway fibroblasts (PAFs). mRNA expression of mucociliary markers and pro-inflammatory cytokines was assessed by qPCR. MUC5AC and MUC5B release in apical wash and pro-inflammatory IL-6, CXCL8 and CCL20 release in basolateral supernatant was measured by ELISA. Immunohistochemical staining was performed on paraffin-embedded transwell inserts using Alcian blue and acetylated α-tubulin. To assess the involvement of the pro-inflammatory mediator IL-6, co-cultures of Calu-3 epithelial cells and PAFs were treated with a neutralizing antibody against IL-6. Upon co-culture with PAFs, PBECs expressed more MUC5B mRNA and secreted higher levels of MUC5AC and MUC5B protein. These effects were accompanied by more pronounced mucous cell differentiation. PAFs expressed higher IL-6 mRNA and secreted more IL-6 upon co-culture with AECs, while IL-6 neutralization attenuated the increase in MUC5B expression by Calu-3 epithelial cells upon co-culture with PAFs. This study demonstrates that fibroblasts support mucous cell differentiation and epithelial mucin release in vitro, and that IL-6 signaling contributes to this fibroblast-driven MUC5B expression. These findings support the notion that stromal-epithelium crosstalk within the local niche may contribute to CMH in COPD.

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