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Updated: Aug 15, 2026
Oropharyngeal Administration of Bleomycin in the Murine Model of Pulmonary Fibrosis
Published on: May 9, 2025
[AP-1 Decoy modulating MMP-2/TIMP-1 imbalance induced by bleomycin-A5 in pulmonary fibroblasts]
Wan-li Ma1, Hong Ye, Jian-bao Xin
1Department of Respiratory Medicine, Xiehe Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430022, China.
Objective:
To investigate the effect of AP-1 Decoy on matrix metalloproteinase 2 (MMP-2) and tissue inhibitor of metalloproteinase (TIMP-1) imbalance induced by bleomycin-A5 (BLM-A5) in pulmonary fibroblasts.
Methods:
Pulmonary fibroblasts were primary cultured, and transferred with AP-1 Decoy before treated with BLM-A5. MMPs activity in medium was determined by gelatin zymography. Protein content of TIMP-1 in medium was detected by ELISA. Expression of MMP-2 mRNA and TIMP-1 mRNA were determined by reverse transcriptase-polymerase chain reaction (RT-PCR).
Results:
BLM-A5 induced the increase in activity of MMP-2 at 12 h [A: (0.77 +/- 0.08) vs (0.65 +/- 0.07) P < 0.05], but it was suppressed by AP-1 Decoy [A: (0.68 +/- 0.05)]. BLM-A5 up-regulated the expression of protein and mRNA of TIMP-1 after 12 h, and 24 h [(39.3 +/- 4.3), (46.3 +/- 4.8) ng/ml vs (28.9 +/- 2.7), (31.6 +/- 2.4) ng/ml] and [Absorbance ratio to beta-actin: (0.94 +/- 0.13, 1.08 +/- 0.06) vs (0.76 +/- 0.07, 0.75 +/- 0.08)] (P < 0.05 or P < 0.01) but AP-1 Decoy modulated the up-regulation. All these indexes in AP-1 Decoy group had no significant difference in contrast to the normal group. Mutant AP-1 Decoy had not the same function as AP-1 Decoy on the expression of MMP-2 and TIMP-1 in pulmonary fibroblasts.
Conclusion:
AP-1 Decoy inhibits the increase in MMP-2 activity and the up-regulation of TIMP-1 induced by BLM-A5 in pulmonary fibroblasts.
Insights
AP-1 Decoy treatment inhibited bleomycin-A5-induced increases in matrix metalloproteinase-2 (MMP-2) activity and tissue inhibitor of metalloproteinase-1 (TIMP-1) expression in pulmonary fibroblasts. This suggests AP-1 Decoy may counteract fibrotic responses.
Area of Science:
- Pulmonary medicine
- Molecular biology
- Cell biology
Background:
- Bleomycin-A5 (BLM-A5) induces pulmonary fibrosis by disrupting the balance of matrix metalloproteinases (MMPs) and their inhibitors.
- Matrix metalloproteinase 2 (MMP-2) and tissue inhibitor of metalloproteinase 1 (TIMP-1) play crucial roles in extracellular matrix remodeling and fibrosis.
Purpose of the Study:
- To investigate the therapeutic potential of AP-1 Decoy in modulating MMP-2 and TIMP-1 imbalance caused by BLM-A5 in pulmonary fibroblasts.
- To determine if AP-1 Decoy can reverse the fibrotic effects induced by BLM-A5.
Main Methods:
- Primary pulmonary fibroblasts were cultured and treated with AP-1 Decoy before exposure to BLM-A5.
- MMP activity was assessed using gelatin zymography.
- TIMP-1 protein levels were quantified via ELISA.
- MMP-2 and TIMP-1 mRNA expression was analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR).
Main Results:
- BLM-A5 significantly increased MMP-2 activity and TIMP-1 expression (protein and mRNA) in pulmonary fibroblasts.
- AP-1 Decoy treatment suppressed the BLM-A5-induced increase in MMP-2 activity.
- AP-1 Decoy modulated the up-regulation of TIMP-1 expression, bringing levels back to normal.
- Mutant AP-1 Decoy did not exhibit the same inhibitory effects, confirming the specificity of AP-1 Decoy.
Conclusions:
- AP-1 Decoy effectively inhibits BLM-A5-induced MMP-2 activity and TIMP-1 up-regulation in pulmonary fibroblasts.
- AP-1 Decoy demonstrates potential as a therapeutic agent to counteract BLM-A5-induced pulmonary fibrosis by restoring protease-antiprotease balance.
