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Updated: Aug 31, 2026
Detection of Inflammasome Activation and Pyroptotic Cell Death in Murine Bone Marrow-derived Macrophages
Published on: May 21, 2018
Cathepsin B/NLRP3/GSDMD axis-mediated macrophage pyroptosis induces inflammation and fibrosis in systemic sclerosis
Chaofan Liu1, Jiaxuan Tang1, Shiying Liu1
1Department of Dermatology, Zhongshan Hospital, Fudan University, Shanghai, China.
Background:
Pyroptosis is a newly discovered type of programmed cell death associated with inflammatory and fibrotic diseases. Macrophages play an important role in inducing early immune inflammation in systemic sclerosis (SSc).
Objective:
To investigate the effect of macrophages pyroptosis on fibrosis of SSc.
Methods:
Pyroptosis/inflammatory markers in serum and skin of SSc patients were detected. Bleomycin (BLM) was subcutaneously injected to establish SSc mouse model. The levels of pyroptosis markers, dermal thickness and collagen deposition in skin were assessed before and after the administration of pyroptosis inhibitors, including MCC950, Disulfiram and necrosulfonamide (NSA). Human-derived monocyte-macrophage cell line (THP-1) or mouse bone marrow-derived macrophages (BMDMs) were primed with lipopolysaccharide (LPS) and stimulated by silicon dioxide (SiO2) to induce cell pyroptosis. Fibroblasts from patients with SSc were co-cultured with pyroptotic THP-1 cells, and the collagen production was assessed.
Results:
Pyroptotic/inflammatory proteins, including NLRP3, cleaved-Caspase (CASP)1, GSDMD-N terminal and IL-18 were increased in the serum, and ASC aggregation and GSDMD were elevated in macrophages in the skin of SSc patients. SSc mice showed increased pyroptosis markers, dermal thickness and collagen deposition in skins, which were alleviated by MCC950, Disulfiram and NSA. Pyroptosis of THP-1 cells and BMDMs was induced by LPS/SiO2, and it was reduced by the inhibitors of Cathepsin B, NLRP3, CASP1 and GSDMD. Co-culture with pyroptotic THP-1 cells increased the fibrotic proteins in fibroblasts, which were alleviated by pyroptosis inhibitors.
Conclusions:
SSc patients and BLM-induced mouse model presented increased pyroptosis. LPS/SiO2-induced macrophage pyroptosis promoted fibrosis of SSc through Cathepsin B/NLRP3/GSDMD pathway.
Insights
Pyroptosis, a programmed cell death, drives fibrosis in systemic sclerosis (SSc). Inhibiting this process in macrophages alleviates SSc symptoms and collagen deposition in a mouse model.
Area of Science:
- Immunology
- Cell Biology
- Pathology
Background:
- Pyroptosis is a programmed cell death pathway linked to inflammatory and fibrotic diseases.
- Macrophages are key in initiating early immune responses in systemic sclerosis (SSc).
Purpose of the Study:
- To investigate the role of macrophage pyroptosis in the development of SSc fibrosis.
- To assess the therapeutic potential of pyroptosis inhibitors in SSc.
Main Methods:
- Assessed pyroptosis and inflammatory markers in SSc patient serum and skin.
- Established an SSc mouse model using bleomycin (BLM) and treated with pyroptosis inhibitors (MCC950, Disulfiram, NSA).
- Induced pyroptosis in macrophage cell lines (THP-1, BMDMs) and co-cultured with SSc fibroblasts to evaluate collagen production.
Main Results:
- SSc patients and mice exhibited elevated pyroptosis markers (NLRP3, cleaved-CASP1, GSDMD, IL-18).
- Pyroptosis inhibitors reduced dermal thickness and collagen deposition in SSc mice.
- Inhibition of pyroptosis in macrophages decreased pro-fibrotic signaling in SSc fibroblasts.
Conclusions:
- Increased pyroptosis is evident in SSc patients and a BLM-induced mouse model.
- Macrophage pyroptosis promotes SSc fibrosis via the Cathepsin B/NLRP3/GSDMD pathway.
- Targeting pyroptosis offers a potential therapeutic strategy for SSc.
