M2 macrophages promote subconjunctival fibrosis through YAP/TAZ signalling

Abstract

Purpose

To evaluate the role of M2 macrophages in subconjunctival fibrosis after silicone implantation (SI) and investigate the underlying mechanisms.

Materials and methods

A model of subconjunctival fibrosis was established by SI surgery in rabbit eyes. M2 distribution and collagen deposition were evaluated by histopathology. The effects of M2 cells on the migration (using wound-scratch assay) and activation (by immunofluorescence and western blotting) of human Tenon’s fibroblasts (HTFs) were investigated.

Results

There were more M2 macrophages (CD68+/CD206+ cells) occurring in tissue samples around silicone implant at 2 weeks postoperatively. Dense collagen deposition was observed at 8 weeks after SI. In vitro experiment showed M2 expressed high level of CD206 and transforming growth factor-β1 (TGF-β1). The M2-conditioned medium promoted HTFs migration and the synthesis of collagen I and fibronectin. Meanwhile, M2-conditioned medium increased the protein levels of TGF-β1, TGF-βR II, p-Smad2/3, yes-associated protein (YAP), and transcriptional coactivator with PDZ-binding motif (TAZ). Verteporfin, a YAP inhibitor, suppressedTGF-β1/Smad2/3-YAP/TAZ pathway and attenuated M2-induced extracellular matrix deposition by HTFs.

Conclusions

TGF-β1/Smad2/3-YAP/TAZ signalling may be involved in M2-induced fibrotic activities in HTFs. M2 plays a key role in promoting subconjunctival fibrosis and can serve as an attractive target for anti-fibrotic therapeutics.

Keywords:

• Subconjunctival fibrosis
• macrophage
• M2 polarization
• YAP
• fibroblast

Authors contributions

Yiwei Wang: investigation, methodology, writing—original draft preparation and funding acquisition. Xingchen Geng: investigation, methodology, writing—original draft preparation. Zhihua Guo: investigation, methodology. Dandan Chu: investigation, methodology. Ruixing Liu: investigation, methodology. Boyuan Cheng: data curation and formal analysis. Haohao Cui: data curation and formal analysis. Chengcheng Li: data curation and formal analysis. Jingguo Li: conceptualization, funding acquisition, project administration, resources, supervision, validation, writing, review and editing. Zhanrong Li: conceptualization, funding acquisition, investigation, methodology, project administration, resources, supervision, validation, writing, review and editing.

Disclosure statement

The authors report no conflict of interest.

Data availability statement

The data that support the findings of this study are available from the corresponding author, Z. Li, upon reasonable request.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (82201190, 82371108 and 52173143), the Medical Science and Technology Project of Henan Province (SBGJ202103018) and the Basic Science Key Project of Henan Eye Hospital (20JCZD002, 23JCZD0031 and 22JCQN009).