ORIGINAL RESEARCH article
Front. Immunol.
Sec. Autoimmune and Autoinflammatory Disorders : Autoimmune Disorders
This article is part of the Research TopicHunting for Inflammation Mediators: Identifying Novel Biomarkers for Autoimmune and Autoinflammatory DiseasesView all 16 articles
S100A8/S100A9 through PAD4 activation of neutrophil extracellular traps promotes granulomatous lobular mastitis
Provisionally accepted
- Nanjing University Medical School Affiliated Nanjing Drum Tower Hospital, Nanjing, China
Select one of your emails
You have multiple emails registered with Frontiers:
Notify me on publication
Please enter your email address:
If you already have an account, please login
You don't have a Frontiers account ? You can register here
Background: Granulomatous lobular mastitis (GLM) is a nonspecific chronic inflammatory breast disorder with an obscure etiology and pathogenesis. Neutrophil extracellular traps (NETs), which are extracellular web-like structures composed of decondensed chromatin and granular proteins released by activated neutrophils, disrupt normal tissue architecture and perpetuate inflammatory responses. The aim of the present study was to explore the role of NETs in GLM and the underlying regulatory mechanisms. Methods: Neutrophils were isolated from the blood of GLM patients and healthy controls (HCs) to assess NET formation. The presence of NETs in GLM tissues was detected using Western blot, immunohistochemistry, and immunofluorescence analyses. A mouse model of GLM was established to determine whether the inhibition of NET production, which is dependent on S100A8/S100A9, alleviates mammary gland inflammation. The potential mechanisms and therapeutic implications were further explored through in vitro and in vivo assays. Results: NETs were significantly increased in GLM tissues, as characterized by elevated levels of citrullinated histone H3 (CitH3) and myeloperoxidase (MPO). S100A8/S100A9 was highly expressed in GLM and demonstrated significant diagnostic value alongside NET markers. Mechanistically, S100A8/S100A9 promoted NETosis through interactions with peptidylarginine deiminase 4 (PAD4). Both paquinimod (an S100A8/S100A9 inhibitor) and Cl-amidine (a PAD4 inhibitor) effectively suppressed NET formation in vitro. In the GLM mouse model, both inhibitors reduced mammary gland inflammation, NET accumulation, and tissue damage. Conclusions: The present findings indicated that NETs contribute to the pathogenesis of GLM. S100A8/S100A9 plays a critical role in promoting NET formation via PAD4 activation. Targeting this axis with paquinimod effectively inhibits NETosis and alleviates GLM, suggesting a promising therapeutic strategy for GLM and other inflammatory diseases.
Keywords: Granulomatous lobular mastitis, neutrophil extracellular traps, S100A8/S100A9, Paquinimod, pad4
Received: 24 Jul 2025; Accepted: 29 Nov 2025.
Copyright: © 2025 Zhu, yu, Wang, Sun, Wang, Ma and Yao. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Yongzhong Yao
Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.