Epigenetic regulation in radiation-induced pulmonary fibrosis

Hydrogen therapy promotes macrophage polarization to the M2 subtype in radiation lung injury by inhibiting the NF-κB signalling pathway

Background

Radiotherapy has become a standard treatment for chest tumors, but a common complication of radiotherapy is radiation lung injury. Currently, there is still a lack of effective treatment for radiation lung injury.

Methods

A mouse model of radioactive lung injury (RILI) was constructed and then treated with different cycles of hydrogen inhalation. Lung function tests were performed to detect changes in lung function.HE staining was used to detect pathological changes in lung tissue. Immunofluorescence staining was used to detect the polarization of macrophages in lung tissue. Immunohistochemistry was used to detect changes in cytokine expression in lung tissues. Western Blot was used to detect the expression of proteins related to the NF-κB signalling pathway.

Results

Lung function test results showed that lung function decreased in the model group and improved in the treatment group.HE staining showed that inflammatory response was evident in the model group and decreased in the treatment group. Immunohistochemistry results showed that the expression of pro-inflammatory factors was significantly higher in the model group, and the expression of pro-inflammatory factors was significantly higher in the treatment group. The expression of pro-inflammatory factors in the treatment group was significantly lower than that in the model group, and the expression of anti-inflammatory factors in the treatment group was higher than that in the model group. Immunofluorescence showed that the expression of M1 subtype macrophages was up-regulated in the model group and down-regulated in the treatment group. The expression of M2 subtype macrophages was up-regulated in the treatment group relative to the model group. Western Blot showed that P-NF-κB p65/NF-κB p65 was significantly increased in the model group, and P-NF-κB p65/NF-κB p65 was decreased in the treatment group.

Conclusion

Hydrogen therapy promotes macrophage polarization from M1 to M2 subtypes by inhibiting the NF-κB signalling pathway, thereby attenuating the inflammatory response to radiation lung injury.

Epigenetic regulation of TGF-β pathway and its role in radiation response

PURPOSE

Transforming growth factor (TGF-β) plays a dual role in tumor progression as well as a pivotal role in radiation response. TGF-β-related epigenetic regulations, including DNA methylation, histone modifications (including methylation, acetylation, phosphorylation, ubiquitination), chromatin remodeling and non-coding RNA regulation, have been found to affect the occurrence and development of tumors as well as their radiation response in multiple dimensions. Due to the significance of radiotherapy in tumor treatment and the essential roles of TGF-β signaling in radiation response, it is important to better understand the role of epigenetic regulation mechanisms mediated by TGF-β signaling pathways in radiation-induced targeted and non-targeted effects.

CONCLUSIONS

By revealing the epigenetic mechanism related to TGF-β-mediated radiation response, summarizing the existing relevant adjuvant strategies for radiotherapy based on TGF-β signaling, and discovering potential therapeutic targets, we hope to provide a new perspective for improving clinical treatment.

High-Fat Diet Related Lung Fibrosis-Epigenetic Regulation Matters

Pulmonary fibrosis (PF) is an interstitial lung disease characterized by the destruction of the pulmonary parenchyma caused by excessive extracellular matrix deposition. Despite the well-known etiological factors such as senescence, aberrant epithelial cell and fibroblast activation, and chronic inflammation, PF has recently been recognized as a metabolic disease and abnormal lipid signature was observed both in serum and bronchoalveolar lavage fluid (BALF) of PF patients and mice PF model. Clinically, observational studies suggest a significant link between high-fat diet (HFD) and PF as manifested by high intake of saturated fatty acids (SFAs) and meat increases the risk of PF and mice lung fibrosis. However, the possible mechanisms between HFD and PF remain unclear. In the current review we emphasize the diversity effects of the epigenetic dysregulation induced by HFD on the fibrotic factors such as epithelial cell injury, abnormal fibroblast activation and chronic inflammation. Finally, we discuss the potential ways for patients to improve their conditions and emphasize the prospect of targeted therapy based on epigenetic regulation for scientific researchers or drug developers.

Mesenchymal Stem Cells in Radiation-Induced Pulmonary Fibrosis: Future Prospects

Radiation-induced pulmonary fibrosis (RIPF) is a general and fatal side effect of radiotherapy, while the pathogenesis has not been entirely understood yet. By now, there is still no effective clinical intervention available for treatment of RIPF. Recent studies revealed mesenchymal stromal cells (MSCs) as a promising therapy treatment due to their homing and differentiation ability, paracrine effects, immunomodulatory effects, and MSCs-derived exosomes. Nevertheless, problems and challenges in applying MSCs still need to be taken seriously. Herein, we reviewed the mechanisms and challenges in the applications of MSCs in treating RIPF.

The Promising Therapeutic Approaches for Radiation-Induced Pulmonary Fibrosis: Targeting Radiation-Induced Mesenchymal Transition of Alveolar Type II Epithelial Cells

Radiation-induced pulmonary fibrosis (RIPF) is a common consequence of radiation for thoracic tumors, and is accompanied by gradual and irreversible organ failure. This severely reduces the survival rate of cancer patients, due to the serious side effects and lack of clinically effective drugs and methods. Radiation-induced pulmonary fibrosis is a dynamic process involving many complicated and varied mechanisms, of which alveolar type II epithelial (AT2) cells are one of the primary target cells, and the epithelial-mesenchymal transition (EMT) of AT2 cells is very relevant in the clinical search for effective targets. Therefore, this review summarizes several important signaling pathways that can induce EMT in AT2 cells, and searches for molecular targets with potential effects on RIPF among them, in order to provide effective therapeutic tools for the clinical prevention and treatment of RIPF.