Radiation-induced Pulmonary Fibrosis Research Articles

Rosmarinic Acid Alleviates Radiation-Induced Pulmonary Fibrosis by Downregulating the tRNA N7-Methylguanosine Modification-Regulated Fibroblast-to-Myofibroblast Transition Through the Exosome Pathway

Rosmarinic Acid Alleviates Radiation-Induced Pulmonary Fibrosis by Downregulating the tRNA N7-Methylguanosine Modification-Regulated Fibroblast-to-Myofibroblast Transition Through the Exosome Pathway

DNA-PKcs/AKT1 inhibits epithelial-mesenchymal transition during radiation-induced pulmonary fibrosis by inducing ubiquitination and degradation of Twist1.

Radiation-induced pulmonary fibrosis (RIPF) is a chronic, progressive, irreversible lung interstitial disease that develops after radiotherapy. Although several previous studies have focused on the mechanism of epithelial-mesenchymal transition (EMT) in lung epithelial cells, the essential factors involved in this process remain poorly understood. The DNA-dependent protein kinase catalytic subunit (DNA-PKcs) exhibits strong repair capacity when cells undergo radiation-induced damage; whether DNA-PKcs regulates EMT during RIPF remains unclear. To investigate the role and molecular mechanism of DNA-PKcs in RIPF and provide an important theoretical basis for utilising DNA-PKcs-targeted drugs for preventing RIPF. DNA-PKcs knockout (DPK-/-) mice were generated via the Cas9/sgRNA technique and subjected to whole chest ionizing radiation (IR) at a 20Gy dose. Before whole chest IR, the mice were intragastrically administered the DNA-PKcs-targeted drug VND3207. Lung tissues were collected at 1 and 5 months after IR. The expression of DNA-PKcs is low in pulmonary fibrosis (PF) patients. DNA-PKcs deficiency significantly exacerbated RIPF by promoting EMT in lung epithelial cells. Mechanistically, DNA-PKcs deletion by shRNA or inhibitor NU7441 maintained the protein stability of Twist1. Furthermore, AKT1 mediated the interaction between DNA-PKcs and Twist1. High Twist1 expression and EMT-associated changes caused by DNA-PKcs deletion were blocked by insulin-like growth factor-1 (IGF-1), an AKT1 agonist. The radioprotective drug VND3207 prevented IR-induced EMT and alleviated RIPF in mice by stimulating the kinase activity of DNA-PKcs. Our study clarified the critical role and mechanism of DNA-PKcs in RIPF and showed that it could be a potential target for preventing RIPF.

The Preventive Effect of Endostar on Radiation-induced Pulmonary Fibrosis.

Radiation-induced pulmonary fibrosis (RIPF) is a long-term complication of thoracic radiotherapy without effective treatment available. This study aimed to establish a RIPF mouse model and explore the therapeutic effects and mechanisms of recombinant human endostatin (Endostar). C57BL/6 mice received a 16-Gy dose of X-rays to the whole thorax with or without the administration of Endostar for 24 weeks. Radiation-induced body weight loss was partially attenuated by Endostar (P<0.05). Endostar significantly reduced alveolar inflammation (P<0.05) and pulmonary fibrosis (P<0.001), as indicated by a decrease in the expression levels of collagen I and collagen IV in lung tissue (both P<0.001). Angiogenesis (as shown by CD31 immunohistochemistry) was also decreased (P<0.01). In irradiated mice, Endostar inhibited the transforming growth factor-β1 (TGF-β1)/drosophila mothers against the decapentaplegic 3 (Smad3)/extracellular regulated protein kinases (ERK) signaling pathway (all P<0.05). In vitro, Endostar treatment decreased the radiation-induced expression of TGF-β1, vascular endothelial growth factor (VEGF), p-Smad3, and p-ERK in alveolar epithelial cells and vascular endothelial cells (all P<0.05). Endostar could alleviate RIPF through decreased antiangiogenic activity and inhibition of the TGF-β1/Smad3/ERK pathway.

789: Integrin antagonism to mitigate radiation-induced pulmonary fibrosis: iDISCO-based 3-D SHG imaging

789: Integrin antagonism to mitigate radiation-induced pulmonary fibrosis: iDISCO-based 3-D SHG imaging

Targeted lung therapy with rosmarinic acid encapsulated in PLGA microspheres for radiation-induced pulmonary fibrosis

Radiation-induced pulmonary fibrosis (RIPF) is a frequent complication among individuals affected by nuclear accidents and patients undergoing chest radiation therapy for tumors. However, the availability of effective drugs for prevention and treatment of RIPF remains limited. Rosmarinic acid (RA), which displays inhibitory properties against RIPF, suffers from poor targeting in previous drug studies. To overcome this issue and achieve optimal therapeutic effects, continuous administration over several days is usually employed. In this study, we developed PLGA microspheres with an average size of 17 μm and drug loading efficiency of 24.97 % (±0.97 %), loaded with RA (RA/PLGAMS) using the membrane emulsification method. By controlling the size of microspheres in the pulmonary capillaries, we achieved lung targeting of microspheres, and based on the release of drugs as PLGA degrades, the residence time of drugs in the body is prolonged. And it was confirmed by in vivo imaging and SEM imaging that PLGAMS could exist in the lungs for at least 7 days. Our results demonstrated successful targeting of the lungs in a mouse model and sustained release of RA encapsulated in the PLGA microspheres. Notably, under the same administration conditions, the therapeutic efficacy of PLGA-encapsulated RA surpassed that of ordinary RA. We observed decreased expression of inflammatory factors, reduced M2 macrophage polarization, and weakened epithelial mesenchymal transformation following our treatment, which might explain the radiation damage alleviating effect of RA. After treatment, it was shown that the deep inspiratory capacity of the mice improved by 57.8 %, and WB showed a decrease of 52.4 % and 28.3 % in the expression of epithelial mesenchymal transition related proteins (TGF-β1 and α-SMA). In summary, PLGA microspheres offer a promising drug delivery system and treatment strategy for radiation-induced pulmonary fibrosis.

Thoracic Proton Minibeam Radiation Therapy: Tissue Preservation and Survival Advantage Over Conventional Proton Therapy

PurposeProton Minibeam Radiotherapy (pMBRT) is an innovative radiation therapy approach that highly modulates the spatial dimension of the dose delivery using narrow, parallel, and submillimetric proton beamlets. pMBRT has proven its remarkable healthy tissue preservation in the brain and skin. This study assesses the potential advantages of pMBRT for thoracic irradiations compared to conventional radiotherapy in terms of normal tissue toxicity. The challenge here was the influence of respiratory motion on the typical peak and valley dose patterns of pMBRT and its potential biological impact. Methods and materialsthe whole thorax of naïve C57BL/6 mice received one fraction of high dose (18 Gy) pMBRT or conventional proton therapy (CPT) without any respiratory control. The development of radiation-induced pulmonary fibrosis was longitudinally monitored using cone-beam computed tomography. Anatomopathological analysis was carried out at 9 months post-irradiation and focused on the reaction of the lungs’ parenchyma and the response of cell types involved in the development of radiation-induced fibrosis and lung regeneration as Alveolar Type II (AT2) epithelial cells, club cells, and macrophages. ResultspMBRT has milder effects on survival, skin reactions, and lung fibrosis compared to CPT. The pMBRT-induced lung changes were more regional and less severe, with evidence of potential reactive proliferation of AT2 epithelial cells and less extensive depletion of club cells and macrophage invasion than the more damaging effects observed in CPT. ConclusionpMBRT appears suitable to treat moving targets, holding a significant ability to preserve healthy lung tissue, even without respiratory control or precise targeting.

Development of a Radiation-induced Pulmonary Fibrosis Partial Body Irradiation Model in C57BL/6 Mice.

With the current volatile geopolitical climate, the threat of nuclear assault is high. Exposure to ionizing radiation from either nuclear incidents or radiological accidents often lead to major harmful consequences to human health. Depending on the absorbed dose, the symptoms of the acute radiation syndrome and delayed effects of acute radiation exposure (DEARE) can appear within hours, weeks to months. The lung is a relatively radiosensitive organ with manifestation of radiation pneumonitis as an acute effect, followed by apparent fibrosis in weeks or even months. A recently developed, first-of-its-kind murine model for partial-body irradiation (PBI) injury, which can be used to test potential countermeasures against multi-organ damage such as gastrointestinal (GI) tract and lungs was used for irradiation, with 2.5% bone marrow spared (BM2.5-PBI) from radiation exposure. Long-term damage to lungs from radiation was evaluated using µ-CT scans, pulmonary function testing, histopathological parameters and molecular biomarkers. Pulmonary fibrosis was detected by ground glass opacity observed in µ-CT scans of male and female C57BL/6J mice 6-7 months after BM2.5-PBI. Lung mechanics assessments pertaining to peripheral airways suggested fibrotic lungs with stiffer parenchymal lung tissue and reduced inspiratory capacity in irradiated animals 6-7 months after BM2.5-PBI. Histopathological evaluation of the irradiated lungs revealed presence of focal and diffuse pleural, and parenchymal inflammatory and fibrotic lesions. Fibrosis was confirmed by elevated levels of collagen when compared to lungs of age-matched naïve mice. These findings were validated by findings of elevated levels of pro-fibrotic biomarkers and reduction in anti-inflammatory proteins. In conclusion, a long-term model for radiation-induced pulmonary fibrosis was established, and countermeasures could be screened in this model for survival and protection/mitigation or recovery from radiation-induced pulmonary damage.

SLC15A3 plays a crucial role in pulmonary fibrosis by regulating macrophage oxidative stress.

Idiopathic pulmonary fibrosis (IPF) is a fatal and irreversible disease with few effective treatments. Alveolar macrophages (AMs) are involved in the development of IPF from the initial stages due to direct exposure to air and respond to external oxidative damage (a major inducement of pulmonary fibrosis). Oxidative stress in AMs plays an indispensable role in promoting fibrosis development. The oligopeptide histidine transporter SLC15A3, mainly expressed on the lysosomal membrane of macrophages and highly expressed in the lung, has proved to be involved in innate immune and antiviral signaling pathways. In this study, we demonstrated that during bleomycin (BLM)- or radiation-induced pulmonary fibrosis, the recruitment of macrophages induced an increase of SLC15A3 in the lung, and the deficiency of SLC15A3 protected mice from pulmonary fibrosis and maintained the homeostasis of the pulmonary microenvironment. Mechanistically, deficiency of SLC15A3 resisted oxidative stress in macrophages, and SLC15A3 interacted with the scaffold protein p62 to regulate its expression and phosphorylation activation, thereby regulating p62-nuclear factor erythroid 2-related factor 2 (NRF2) antioxidant stress pathway protein, which is related to the production of reactive oxygen species (ROS). Overall, our data provided a novel mechanism for targeting SLC15A3 to regulate oxidative stress in macrophages, supporting the therapeutic potential of inhibiting or silencing SLC15A3 for the precautions and treatment of pulmonary fibrosis.

The Sphingolipid-Modulating Drug Opaganib Protects against Radiation-Induced Lung Inflammation and Fibrosis: Potential Uses as a Medical Countermeasure and in Cancer Radiotherapy.

Fibrosis is a chronic pathology resulting from excessive deposition of extracellular matrix components that leads to the loss of tissue function. Pulmonary fibrosis can follow a variety of diverse insults including ischemia, respiratory infection, or exposure to ionizing radiation. Consequently, treatments that attenuate the development of debilitating fibrosis are in desperate need across a range of conditions. Sphingolipid metabolism is a critical regulator of cell proliferation, apoptosis, autophagy, and pathologic inflammation, processes that are all involved in fibrosis. Opaganib (formerly ABC294640) is the first-in-class investigational drug targeting sphingolipid metabolism for the treatment of cancer and inflammatory diseases. Opaganib inhibits key enzymes in sphingolipid metabolism, including sphingosine kinase-2 and dihydroceramide desaturase, thereby reducing inflammation and promoting autophagy. Herein, we demonstrate in mouse models of lung damage following exposure to ionizing radiation that opaganib significantly improved long-term survival associated with reduced lung fibrosis, suppression of granulocyte infiltration, and reduced expression of IL-6 and TNFα at 180 days after radiation. These data further demonstrate that sphingolipid metabolism is a critical regulator of fibrogenesis, and specifically show that opaganib suppresses radiation-induced pulmonary inflammation and fibrosis. Because opaganib has demonstrated an excellent safety profile during clinical testing in other diseases (cancer and COVID-19), the present studies support additional clinical trials with this drug in patients at risk for pulmonary fibrosis.

The transcription factor GATA3 positively regulates NRP1 to promote radiation-induced pulmonary fibrosis

Radiation-Induced Pulmonary Fibrosis (RIPF) frequently arises as a delayed complication following radiation therapy for thoracic cancers, encompassing lung, breast, and esophageal malignancies. Characterized by a relentless and irreversible accumulation of extracellular matrix (ECM) proteins within the lung parenchyma, RIPF presents a significant clinical challenge. While the modulation of gene expression by transcription factors is a recognized aspect in various pathologies, their specific role in the context of RIPF has been less clear. This study elucidates that ionizing radiation prompts the translocation of the transcription factor GATA3 into the nucleus. This translocation facilitates GATA3's binding to the NRP1 promoter, thereby enhancing the transcription and subsequent translation of NRP1. Further investigations demonstrate that the TGF-β pathway agonist, SRI-011381, can mitigate the effects of NRP1 knockdown on epithelial-mesenchymal transition (EMT) and ECM deposition, suggesting a pivotal role of the GATA3/NRP1/TGF-β axis in the pathogenesis of RIPF. In conclusion, our findings not only underscore the critical involvement of GATA3 in RIPF but also highlight the GATA3/NRP1/TGF-β signaling pathway as a promising target for therapeutic intervention in RIPF management.

Inhibition of TGFβ1 activation prevents radiation-induced lung fibrosis.

Radiotherapy is the main treatment modality for thoracic tumours, but it may induce pulmonary fibrosis. Currently, the pathogenesis of radiation-induced pulmonary fibrosis (RIPF) is unclear, and effective treatments are lacking. Transforming growth factor beta 1 (TGFβ1) plays a central role in RIPF. We found that activated TGFβ1 had better performance for radiation pneumonitis (RP) risk prediction by detecting activated and total TGFβ1 levels in patient serum. αv integrin plays key roles in TGFβ1 activation, but the role of αv integrin-mediated TGFβ1 activation in RIPF is unclear. Here, we investigated the role of αv integrin-mediated TGFβ1 activation in RIPF and the application of the integrin antagonist cilengitide to prevent RIPF. ItgavloxP/loxP ;Pdgfrb-Cre mice were generated by conditionally knocking out Itgav in myofibroblasts, and wild-type mice were treated with cilengitide or placebo. All mice received 16Gy of radiation or underwent a sham radiation procedure. Lung fibrosis was measured by a modified Ashcroft score and microcomputed tomography (CT). An enzyme-linked immunosorbent assay (ELISA) was used to measure the serum TGFβ1 concentration, and total Smad2/3 and p-Smad2/3 levels were determined via Western blotting. Conditional Itgav knockout significantly attenuated RIPF (p<.01). Hounsfield units (HUs) in the lungs were reduced in the knockout mice compared with the control mice (p<.001). Conditional Itgav knockout decreased active TGFβ1 secretion and inhibited fibroblast p-Smad2/3 expression. Exogenous active TGFβ1, but not latent TGFβ1, reversed these reductions. Furthermore, cilengitide treatment elicited similar results and prevented RIPF. The present study revealed that conditional Itgav knockout and cilengitide treatment both significantly attenuated RIPF in mice by inhibiting αv integrin-mediated TGFβ1 activation. Activated TGFβ1 has a superior capacity in predicting radiation pneumonitis (RP) risk and plays a vital role in the development of radiation-induced pulmonary fibrosis (RIPF). Conditional knock out Itgav in myofibroblasts prevented mice from developing RIPF. Cilengitide alleviated the development of RIPF by inhibiting αv integrin-mediated TGFβ1 activation and may be used in targeted approaches for preventing RIPF.

Nintedanib Mitigates Radiation-Induced Pulmonary Fibrosis by Suppressing Epithelial Cell Inflammatory Response and Inhibiting Fibroblast-to-Myofibroblast Transition.

Radiation-induced pulmonary fibrosis (RIPF) represents a serious complication observed in individuals undergoing thoracic radiation therapy. Currently, effective interventions for RIPF are unavailable. Prior research has demonstrated that nintedanib, a Food and Drug Administration (FDA)-approved anti-fibrotic agent for idiopathic pulmonary fibrosis, exerts therapeutic effects on chronic fibrosing interstitial lung disease. This research aimed to investigate the anti-fibrotic influences of nintedanib on RIPF and reveal the fundamental mechanisms. To assess its therapeutic impact, a mouse model of RIPF was established. The process involved nintedanib administration at various time points, both prior to and following thoracic radiation. In the RIPF mouse model, an assessment was conducted on survival rates, body weight, computed tomography features, histological parameters, and changes in gene expression. In vitro experiments were performed to discover the mechanism underlying the therapeutic impact of nintedanib on RIPF. Treatment with nintedanib, administered either two days prior or four weeks after thoracic radiation, significantly alleviated lung pathological changes, suppressed collagen deposition, and improved the overall health status of the mice. Additionally, nintedanib demonstrated significant mitigation of radiation-induced inflammatory responses in epithelial cells by inhibiting the PI3K/AKT and MAPK signaling pathways. Furthermore, nintedanib substantially inhibited fibroblast-to-myofibroblast transition by suppressing the TGF-β/Smad and PI3K/AKT/mTOR signaling pathways. These findings suggest that nintedanib exerts preventive and therapeutic effects on RIPF by modulating multiple targets instead of a single anti-fibrotic pathway and encourage the further clinical trials to determine the efficacy of nintedanib in patients with RIPF.

Bufotalin attenuates pulmonary fibrosis via inhibiting Akt/GSK-3β/β-catenin signaling pathway

Idiopathic pulmonary fibrosis (IPF) is a chronic interstitial lung disease with no cure. Bufotalin (BT), an active component extracted from Venenum Bufonis, has been prescribed as a treatment for chronic inflammatory diseases. However, whether BT has antifibrotic properties has never been investigated. In this study, we report on the potential therapeutic effect and mechanism of BT on IPF. BT was shown to attenuate lung injury, inflammation, and fibrosis as well as preserve pulmonary function in bleomycin (BLM)-induced pulmonary fibrosis model. We next confirmed BT's ability to inhibit TGF-β1-induced epithelial-mesenchymal transition (EMT) and myofibroblast activation (including differentiation, proliferation, migration, and extracellular matrix production) in vitro. Furthermore, transcriptional profile analysis indicated the Wnt signaling pathway as a potential target of BT. Mechanistically, BT effectively prevented β-catenin from translocating into the nucleus to activate transcription of profibrotic genes. This was achieved by blunting TGF-β1-induced increases in phosphorylated Akt Ser437 (p-Akt S437) and phosphorylated glycogen synthase kinase (GSK)-3β Ser9 (p-GSK-3β S9), thereby reactivating GSK-3β. Additionally, the antifibrotic effects of BT were further validated in another in vivo model of radiation-induced pulmonary fibrosis. Collectively, these data demonstrated the potent antifibrotic actions of BT through inhibition of Akt/GSK-3β/β-catenin axis downstream of TGF-β1. Thus, BT could be a potential option to be further explored in IPF treatment.

Paclitaxel Aggravating Radiation-Induced Pulmonary Fibrosis Is Associated with the Down-Regulation of the Negative Regulatory Function of Spry2.

Paclitaxel (PTX) is capable of aggravating radiation-induced pulmonary fibrosis (RIPF), but the mechanism is unknown. Spry2 is a negative regulator of receptor tyrosine kinase-related Ras/Raf/extracellular signal regulated kinase (ERK) pathway. This experiment was aimed at exploring whether the aggravation of RIPF by PTX is related to Spry2. The RIPF model was established with C57BL/6 mice by thoracic irradiation, and PTX was administered concurrently. Western blot was used to detect the expression level of ERK signaling molecules and the distribution of Spry2 in the plasma membrane/cytoplasm. Co-immunoprecipitation (co-IP) and immunofluorescence were used to observe the colocalization of Spry2 with the plasma membrane and tubulin. The results showed that PTX-concurrent radiotherapy could aggravate fibrotic lesions in RIPF, downregulate the content of membrane Spry2, and upregulate the levels of p-c-Raf and p-ERK in lung tissue. It was found that knockdown of Spry2 in fibroblast abolished the upregulation of p-c-Raf and p-ERK by PTX. Both co-IP results and immunofluorescence staining showed that PTX increased the binding of Spry2 to tubulin, and microtubule depolymerizing agents could abolish PTX's inhibition of Spry2 membrane distribution and inhibit PTX's upregulation of Raf/ERK signaling. Both nintedanib and ERK inhibitor were effective in relieving PTX-exacerbated RIPF. Taken together, the mechanism of PTX's aggravating RIPF was related to its ability to enhance Spry2's binding to tubulin, thus attenuating Spry2's negative regulation on Raf/ERK pathway. SIGNIFICANCE STATEMENT: This study revealed that paclitaxel (PTX) concurrent radiation therapy exacerbates radiation-induced pulmonary fibrosis during the treatment of thoracic tumors, which is associated with PTX restraining Spry2 and upregulating the Raf/extracellular signal regulated kinase signaling pathway, and provided drug targets for mitigating this complication.

O-38 - PET/CT Imaging of avb6 Integrin to Monitor Radiation-Induced Pulmonary Fibrosis

O-38 - PET/CT Imaging of avb6 Integrin to Monitor Radiation-Induced Pulmonary Fibrosis

MiR-765 as a promising biomarker for low-dose radiation-induced pulmonary fibrosis

High-dose radiation (HDR) is widely used for cancer treatment, but the effectiveness of low-dose radiation (LDR) in the treatment of various diseases is controversial. Therefore, to safely utilize LDR for therapeutic purposes, further research on its numerous biological effects of LDR is required. Interest in the increased use of medical imaging devices or the effects of surrounding living environmental radiation on the human body, particularly on fibrosis, is rapidly increasing. Therefore, this study aimed to verify the relationship between LDR and pulmonary fibrosis by evaluating the changes in fibroblasts after LDR treatment and their associated signaling mechanisms. LDR increased the expression of fibrosis markers COL1A1 and α-SMA, cell proliferation, and migration by activating YAP1 and Twist in fibroblasts. Meanwhile, miRNA was employed as a tool to inhibit LDR-induced fibrosis and it was found that miR-765 simultaneously targeted COL1A1, α-SMA, and YAP1. At the cellular level, miR-765 reduced the proliferation and migration of fibroblasts by suppressing the expression of LDR-induced fibrosis factors COL1A1, α-SMA, and YAP1. The efficacy of miR-765 in vivo was confirmed using bleomycin (BLM)-induced fibrotic mouse model. The characteristics of pulmonary fibrosis were reduced after injection of miR-765-overexpressing cells into BLM-induced fibrotic mice. In addition, the suppression of miR-765 expression in the plasma of patients with pulmonary fibrosis confirmed the negative relationship between pulmonary fibrosis and miR-765 expression. Therefore, this study demonstrates that miR-765 is a potential novel diagnostic biomarker and major target for the development of therapeutic agents to inhibit pulmonary fibrosis.

Small extracellular vesicles from irradiated lung epithelial cells promote the activation of fibroblasts in pulmonary fibrosis

Background Alveolar epithelial injury and dysfunction are the risk factors for radiation-induced pulmonary fibrosis (RIPF). However, it is not clear about the relationship between RIPF and the small extracellular vesicles (sEV) secreted by irradiated alveolar epithelial cells. Based on the activation of fibroblasts, this study explored the role of sEV derived from alveolar epithelial cells in RIPF and the potential mechanisms. Methods Transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and western blotting were used to characterize sEV. Western blotting was used to detect fibrosis-associated proteins. Cell counts and transwell assays were used to evaluate the proliferation and migration ability of fibroblasts. RT-PCR was used to observe the extracellular matrix (ECM) synthesized by fibroblasts, miRNA changes in the sEV were determined by second-generation sequencing. Results TEM, NTA, and western blotting showed the extracellular vesicles with a double-layer membrane structure of approximately 100 nm in diameter. The sEV derived from irradiated A549, HBEC3-KT, and MLE12 cells upregulated FN1 and alpha-SMA proteins expression in fibroblasts and drove the fibroblast to myofibroblast transition, and the sEV from irradiated mouse bronchoalveolar lavage fluid (BALF) affirmed the same results. In addition, the sEV derived from irradiated alveolar epithelial cells significantly increased the migration ability of fibroblasts and the expression of extracellular matrix proteins such as FN1. The results of miRNA sequencing of sEV in BALF of rats with RIPF showed that the metabolic pathway may be important for miRNA to regulate the activation of fibroblasts. Conclusion The sEV derived from radiated pulmonary epithelial cells promote the activation, migration and extracellular matrix proteins expression of lung fibroblasts; miRNA in sEV may be an important molecular that affects the activation of lung fibroblasts.

Differential Oxidative Stress Responses in Type II Airway Epithelial Cells Impact Premature Senescence and Lung Fibrosis Susceptibility

Radiation-Induced Pulmonary Fibrosis (RIPF) is a late toxicity characterized by premature senescence in Type II airway epithelial cells (AECII) and accumulation of alternatively activated (M2) macrophages. Differential susceptibility to RIPF is observed across mouse strains. Based on our prior study of the effects of macrophage variation on RIPF, we hypothesized that intrinsic differences in AECII oxidative stress response across mouse strains also impact susceptibility to RIPF. Ten-week-old female mice from C57L, C57BL6 and C3H/HeN strains were exposed to thoracic irradiation (5x6 Gy, n>5 per group). Fifteen weeks after radiation, lung tissue was collected and examined with Masson-Trichrome staining (histologic changes) and β-galactosidase activity assay (senescence). AECII prepared from mice of each strain were exposed to irradiation. To assess differential gene expression, total RNA was extracted and assessed with a multiplex analysis platform and quantitative PCR. Senescence was assessed by β-galactosidase activity assay in primary AECII after irradiation or after co-culture with M2 macrophages polarized with IL13. Susceptibility to radiation-induced lung injury, survival, and premature AECII senescence vary by mouse strain: C57L (fibrosis-prone), C57BL6J (-intermediate) and C3H/HeN (-resistant). Enriched AECII from each strain exhibited differential expression of genes related to inflammatory responses including SASP production after irradiation. Minimal increased expression of Il1r1 was observed in irradiated and unirradiated AECII from C3H/HeN, however Il1rn levels were markedly elevated in response to irradiation. The expression of Thioredoxin (Txn) and Thioredoxin reductase 1 (Txnrd1) in AECII from C3H/HeN was significantly higher than those observed in other strains. In Vivo, C3H/HeN mouse lungs exhibited the least premature senescence in AECII after irradiation. Premature senescence in AECII irradiated In Vitro or co-cultured with superoxide anion-producing M2 macrophages was substantially less in AECII from C3H/HeN compared to other strains. A comparison of primary AECII from three different mouse strains identified intrinsic differences in expression of major inflammatory signaling (IL1R and IL1RN) and redox homeostasis status (TXN and TXNDR1) molecules. This study is the first to demonstrate that intrinsic differences in AECII impacts susceptibility to premature senescence and lung fibrosis after irradiation.

Emetine dihydrochloride alleviated radiation-induced lung injury through inhibiting EMT.

Radiation-induced lung injury (RILI), divided into early radiation pneumonia (RP) and late radiation-induced pulmonary fibrosis (RIPF), is a common serious disease after clinical chest radiotherapy or nuclear accident, which seriously threatens the life safety of patients. There has been no effective prevention or treatment strategy till now. Epithelial-mesenchymal transition (EMT) is a key step in the occurrence and development of RILI. In this study, we demonstrated that emetine dihydrochloride (EDD) alleviated RILI through inhibiting EMT. We found that EDD significantly attenuated EMT-related markers, reduced Smad3 phosphorylation expression after radiation. Then, for the first time, we observed EDD alleviated lung hyperaemia and reduced collagen deposit induced by irradiation, providing protection against RILI. Finally, it was found that EDD inhibited radiation-induced EMT in lung tissues. Our study suggested that EDD alleviated RILI through inhibiting EMT by blocking Smad3 signalling pathways. In summary, our results indicated that EDD is a novel potential radioprotector for RILI.

Activation of Nrf2/ARE pathway by Anisodamine (654-2) for Inhibition of cellular aging and alleviation of Radiation-Induced lung injury

BackgroundRadiation-induced lung injury (RILI) is a common side effect of thoracic tumor radiotherapy, including early-stage radiation-induced lung injury (RP) and late-stage radiation-induced pulmonary fibrosis (RIPF). Currently, it is urgently needed to clarify the pathogenesis of RILI and find safe and effective RILI treatment methods. Irradiation causes DNA damage and oxidative stress in tissues and cells, induces cellular senescence, and promotes the occurrence and development of RILI. In recent years, Anisodamine (654-2) has shown potential therapeutic value in acute lung injury, acute kidney injury, chlamydial pneumonia, and COVID-19. However, there is currently no research on the mechanism of 654-2-mediated cellular senescence and its preventive and therapeutic effects on RILI. PurposeThis study aimed to investigate the protective effect and mechanism of 654-2 on X-ray-induced RILI. MethodsIn vivo experiments involved a mouse RILI model with 18 Gy X-ray irradiation. Mice were divided into control, model, medication (control + 654-2), and treatment (model + 654-2) groups. And mice in medication and treatment groups were intraperitoneal injection of 5 mg/kg 654-2 every other day until being sacrificed at week 6. In vitro experiments used MLE-12 cells irradiated with 16 Gy and divided into control, model, and model + 654-2（2 μM and 10 μM） groups. Various assays were performed to evaluate lung tissue morphology, fibrosis, apoptosis, cytokine expression, cellular senescence, protein expression, and antioxidant capacity. Results654-2 mitigated pulmonary pathological damage, inflammation, DNA damage, cellular senescence, and apoptosis in RILI mice and MLE-12 cells. It restored epithelial cell proliferation ability and enhanced antioxidant capacity. Additionally, 654-2 activated the Nrf2/ARE pathway, increased Nrf2 phosphorylation, and upregulated antioxidant gene expression. Inhibition of Nrf2 reversed the effects of 654-2 on ROS production, antioxidant capacity, and cell senescence. Conclusion654-2 can activate the Nrf2/ARE pathway, enhance cellular antioxidant capacity, and inhibit cellular senescence, thereby exerting a protective effect against RILI.