Vocal fold fibroblasts immunoregulate activated macrophage phenotype

Abstract

Recent evidence suggests that fibroblasts play a critical role in regulating inflammation during wound healing because they express several inflammatory mediators in response to bacteria. The objective of this study was to analyze the effects of lipopolysaccaride (LPS) on the immunomodulatory properties of vocal fold fibroblasts (VFF) derived from polyps, scar and normal tissue co-cultured with macrophages, to provide insight into their interactions during the inflammatory process. Fibroblasts were co-cultured with CD14+ monocytes and after 7 days, wells were treated with LPS for 24 and 72 hours. Culture supernatants were collected and concentrations of TNF-α, IL-6, IL-8, IL-10, IL-12, IL-1β, and MCP-1 were quantified by ELISA. Normal VFF and CD14+ monocultures were used as controls. Twenty-four hours after LPS activation, macrophages co-cultured with polyp VFF had significantly increased expression of TNF-α, IL-1β, IL-12, and IL-10 compared to controls (p<0.0001). In contrast, macrophages co-cultured with scar VFF had significantly lower expression of TNF-α, IL-1β and IL-12 with significantly higher IL-10 compared to control (p<0.0001). After 72 hours, macrophages co-cultured with polyp VFF increased expression of TNF-α, IL-1β, IL-10, IL-6, IL-8, MCP-1 and TGF-β (p<0.01) and macrophages co-cultured with scar VFF significantly decreased their expression of IL-1β and IL-12 compared to control (p<0.0001). Scar VFF at both time points produced significantly lower levels of IL-8, MCP-1, IL-6 and TGF-β compared to controls (p<0.05). Based on our findings, VFF and macrophages secrete several inflammatory mediators that modify their diverse functions. Polyp and scar VFF may play a role in regulating abnormal inflammatory responses, which could result in excessive ECM deposition that disrupts the function of the vocal folds.

Dysregulated Macrophages Are Present in Bleomycin‐Induced Murine Laryngotracheal Stenosis

“…8, 13 Specific to the larynx, other investigators have demonstrated that AAM and fibroblast interaction promotes inflammation associated with vocal fold scarring. 6 …”

Alterations in macrophage polarization in injured murine vocal folds

“…Our results have clarified the distributional and phenotypic changes in macrophages in injured murine vocal folds. The interaction between vocal fold fibroblasts and macrophages was reported in in vitro conditions 26 ; further investigation about the function of macrophages is warranted for a better understanding of wound healing in vocal folds.…”

CD34‐positive fibroblasts in Reinke's edema

“…VFFs produce several inflammatory mediators and play a role in regulating abnormal inflammatory responses by suppressing proinflammatory cytokines and neutrophil recruitment, and interfering with macrophage activation . As mentioned above, VFFs meet the criteria of mesenchymal stem cells, which have immunosuppressive properties, including inhibition of monocyte differentiation, T and B lymphocyte proliferation, and NK cell function.…”

“…VFFs produce several inflammatory mediators 16,21,53 and play a role in regulating abnormal inflammatory responses by suppressing proinflammatory cytokines and neutrophil recruitment, and interfering with macrophage activation. 16,54 As mentioned above, VFFs meet the criteria of mesenchymal stem cells, which have immunosuppressive properties, including inhibition of monocyte differentiation, T and B lymphocyte proliferation, and NK cell function. Thus, it has been demonstrated that VFFs may regulate the immunophenotype of macrophages, which acquire an anti-inflammatory profile based on low CD16, high CD206, and low human leukocyte antigen-DR expression.…”