Dataset Information

In vivo therapeutic success of MicroRNA-155 antagomir in a mouse model of pulmonary fibrosis induced by bleomycin.

ABSTRACT:

Background/aims

MicroRNAs (miRNAs) play critical regulatory roles in the pathogenesis of pulmonary fibrosis. The aim of this study was to explore whether miRNA antagomirs could serve as potential therapeutic agents in interstitial lung diseases.

Methods

A mouse model of pulmonary fibrosis was established by intratracheal injection of bleomycin (BLM). Using microarray analysis, up-regulated miRNAs were identified during the development of pulmonary fibrosis. miR-155 was chosen as the candidate miRNA. Fifteen mice were then randomized into the following three groups: BLM + antagomiR-155 group, treated with BLM plus intravenously injected with antagomiR-155; BLM group, treated with intratracheal BLM plus phosphate-buffered saline (PBS); and a control group, treated with PBS only. Lung tissues were collected for histopathological analysis, hydroxyproline measurement, and Western blotting. Enzyme-linked immunosorbent assays were used for the measurement of cytokines associated with pulmonary fibrosis.

Results

Histological changes and hydroxyproline levels induced by BLM were significantly inhibited by antagomiR-155. The levels of interleukin 4 (IL-4) and transforming growth factor-β (TGF-β) expression were increased after BLM treatment. However, miR-155 silencing decreased the expression of IL-4, TGF-β, and interferon-γ. TGF-β-activated kinase 1/mitogen-activated protein kinase kinase kinase 7 (MAP3K7)-binding protein 2 (TAB2) of the mitogen-activated protein kinase (MAPK) signaling pathway, was activated by BLM and inhibited by in vivo silencing of miR-155 via antagomiR-155.

Conclusion

In vivo treatment with antagomiR-155 alleviated the pathological changes induced by BLM and may be a promising therapeutic strategy for pulmonary fibrosis.

SUBMITTER: Sun X

PROVIDER: S-EPMC8009162 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Pulmonary fibrosis is a disease characterized by inflammatory cell infiltration, scar formation, deposition of extracellular matrix, alveolar epithelial cell injury and hyperplasia. To determine if alterations in microRNA expression contribute to these phenotypes, microRNA expression profiling of the lungs from bleomycin treated C57Bl/6J mice, relative to that of untreated controls, was undertaken. Mice were treated at 8 weeks old with 100 Units/kg of bleomycin delivered subcutaneously with osmotic minipumps. At 42 days post treatment mice were euthanized and lung microRNA isolated. We identified 11 microRNA's to be significantly differentially expressed (FDR threshold of 0.01) in the lungs of bleomycin treated mice and confirmed these data with real time PCR measurements. These included bleomycin upregulated miR-34a, 335-5p, 207, 21, 301a, 146b, 199a-5p, and 449a and bleomycin downregulated miR-151-3p, 26a and 676. We have previously shown that 1558 genes are differentially expressed in the lungs of bleomycin treated mice. Of the 1412 targets of upregulated microRNAs, 142 were confirmed to be downregulated in the gene expression profile (GEP). Of the 583 targets of downregulated microRNAs, 53 were confirmed to be upregulated in the gene expression profile. Pathway analysis of the microRNA targets and GEP overlapping genes indicated that altered microRNA expression is associated with cellular development, cellular growth, cellular proliferation and changed tissue/cell morphology. Specific pathways include HGF signaling, Cholecystokinin/Gastrin-mediated signaling, Endothelin-1 signaling, RAR activation, Phospholipase C signaling and IGF1 signaling. We conclude that altered microRNA expression is a feature of pulmonary fibrosis which putatively influences components of the altered airway disease. Two condition study, C57Bl/6J mice treated with 100 Units/kg bleomycin and untreated controls. Biological replicated n =3 for each group. Left lung tissue.

Project description:BackgroundIdiopathic pulmonary fibrosis is a disease characterized by alveolar epithelial cell injury, inflammatory cell infiltration and deposition of extracellular matrix in lung tissue. As mouse models of bleomycin-induced pulmonary fibrosis display many of the same phenotypes observed in patients with idiopathic pulmonary fibrosis, they have been used to study various aspects of the disease, including altered expression of microRNAs.ResultsIn this work, microRNA expression profiling of the lungs from treated C57BL/6J mice, relative to that of untreated controls, was undertaken to determine which alterations in microRNAs could in part regulate the fibrosis phenotype induced by bleomycin delivered through mini-osmotic pumps. We identified 11 microRNAs, including miR-21 and miR-34a, to be significantly differentially expressed (P < 0.01) in lungs of bleomycin treated mice and confirmed these data with real time PCR measurements. In situ hybridization of both miR-21 and miR-34a indicated that they were expressed in alveolar macrophages. Using a previously reported gene expression profile, we identified 195 genes to be both predicted targets of the 11 microRNAs and of altered expression in bleomycin-induced lung disease of C57BL/6J mice. Pathway analysis with these 195 genes indicated that altered microRNA expression may be associated with hepatocyte growth factor signaling, cholecystokinin/gastrin-mediated signaling, and insulin-like growth factor (IGF-1) signaling, among others, in fibrotic lung disease. The relevance of the IGF-1 pathway in this model was then demonstrated by showing lung tissue of bleomycin treated C57BL/6J mice had increased expression of Igf1 and that increased numbers of Igf-1 positive cells, predominantly in macrophages, were detected in the lungs.ConclusionsWe conclude that altered microRNA expression in macrophages is a feature which putatively influences the insulin-like growth factor signaling component of bleomycin-induced pulmonary fibrosis.