Foxm1 transcription factor is required for lung fibrosis and epithelial-to-mesenchymal transition

Regulation of FOXM1 by HDAC3 Inhibition Ameliorates Macrophage Endoplasmic Reticulum stress and Apoptosis in Mycobacterium tuberculosis Infection

Mycobacterium tuberculosis (Mtb) infection may induce significant damage to the host lung tissues. Endoplasmic reticulum stress (ERS) and apoptosis of macrophages are considered key factors affecting the survival and pathogenicity of intracellular Mtb. Forkhead box M1 (FOXM1) is closely implicated in lung diseases. This study aimed to investigate the role of FOXM1 in Mtb infection and the involvement of histone deacetylase 3 (HDAC3) in this process. An in vitro Mtb infection model was established by infecting RAW264.7 macrophages with Mtb H37Ra. The results showed that RAW264.7 macrophages subjected to Mtb infection showed upregulated expressions of ERS markers and FOXM1. FOXM1 overexpression further elevated the levels of ERS and apoptosis markers, pro-inflammatory cytokines, and reactive oxygen species in Mtb-infected macrophages. FOXM1 could bind to the promoter of TXNIP and activate its transcription. Knockdown of TXNIP suppressed the effects of Mtb infection on macrophages, while upregulation of FOXM1 completely abolished the effects of TXNIP knockdown. HDAC3 inhibitor effectively diminished the effects of FOXM1 upregulation on Mtb-infected macrophages. In conclusion, inhibition of HDAC3 may reduce ERS and apoptosis of Mtb-infected macrophages by regulating the FOXM1/TXNIP axis.

Mechanistic insights into the treatment of pulmonary fibrosis with bioactive components from traditional chinese medicine via matrix stiffness-mediated EMT

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a progressive interstitial lung disease with limited therapeutic options. Our previous research has shown that the Jinshui Huanxian formula (JHF) is effective in treating IPF. However, the biomechanical mechanisms of its refined components, known as the effective-component compatibility of JHF II (ECC-JHF II), are not well understood.

PURPOSE

This study aims to explore how bioactive components from traditional Chinese medicine (TCM) impact the biomechanical progression of pulmonary fibrosis.

STUDY DESIGN AND METHODS

A mouse model of pulmonary fibrosis was established by a single intratracheal instillation of bleomycin (Bleomycin). Pulmonary function, pathological changes, collagen deposition, lung tissue stiffness, and EMT markers were evaluated at the end of the study. Polyethylene glycol hydrogels with adjustable stiffness were used to mimic both normal and pathological lung conditions. The effects of ECC-JHF II on matrix stiffness-mediated EMT were assessed by quantitative real-time PCR, western blot, and immunofluorescence. The biomechanical mechanisms underlying ECC-JHF II on EMT and pulmonary fibrosis were verified both in vivo and in vitro.

RESULTS

ECC-JHF II significantly improved bleomycin (Bleomycin)-induced pulmonary fibrosis in mice, manifested as increased tidal volume and 50 % tidal volume expiratory flow, reduced lung tissue stiffness, and decreased EMT markers. Histopathological analysis showed reduced inflammation, alveolar damage, and collagen deposition. In vitro, ECC-JHF II reversed the EMT phenotypic transition induced by substrate stiffness, demonstrated by the upregulation of E-cadherin, occludin, and zonula occluden-1, and the downregulation of N-cadherin, vimentin, caldesmon 1 and tropomyosin 1. Moreover, ECC-JHF II could inhibit integrin/ROCK/MRTF signaling in vitro and in vivo. Silencing integrin β1 or activating it with pyrintegrin further confirmed the role of integrin β1 in the mechanotransduction pathway and the efficacy of ECC-JHF II.

CONCLUSION

Taken together, the findings of this study indicate that ECC-JHF II exerts a therapeutic effect on pulmonary fibrosis through the attenuation of lung tissue stiffness and inhibition of EMT, potentially via the integrin/ROCK/MRTF signaling pathway.

The Reparative Effect of FOXM1 in Pulmonary Disease

FOXM1, a key member of the FOX transcription factor family, maintains cell homeostasis by accurately controlling diverse biological processes, such as proliferation, cell cycle progression, differentiation, DNA damage repair, tissue homeostasis, angiogenesis, apoptosis, redox signaling, and drug resistance. In recent years, an increasing number of studies have focused on the role of FOXM1 in the occurrence of multiple diseases and various pathophysiological processes. In the field of pulmonary diseases, FOXM1 has a certain reparative effect by promoting cell proliferation, regulating cell cycle, antifibrosis, participating in inflammation regulation, and synergizing with other signaling pathways. On the basis of the repair properties of FOXM1, this review explores its therapeutic potential in acute lung injury/acute respiratory distress syndrome, asthma, chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis, pulmonary arterial hypertension, lung cancer, and other lung diseases, with the goal of providing a new perspective for the analysis of FOXM1-related mechanism of action and the expansion of clinical treatment strategies.

HNRNPC mediates lymphatic metastasis of cervical cancer through m6A-dependent alternative splicing of FOXM1

Cervical cancer (CCa) patients with lymph node (LN) metastasis face poor prognoses and have limited treatment options. Aberrant N6-methyladenosine (m6A) modification of RNAs are known to promote tumor metastasis, but their role in CCa remains unclear. Our study reveals that HNRNPC, an alternative splicing (AS) factor and m6A reader, increases tumor-related variants through m6A-dependent manner, thereby promoting lymphatic metastasis in CCa. We found that HNRNPC overexpression correlates with lymphatic metastasis and poorer prognoses in CCa patients. Functionally, knocking down HNRNPC markedly inhibited the migration and invasion of several CCa cell lines, while supplementing HNRNPC restored the malignant phenotypes of these cells. Mechanistically, HNRNPC regulates exon skipping of FOXM1 by binding to its m6A-modified motif. Mutating the m6A site on FOXM1 weakened the interaction between HNRNPC and FOXM1 pre-RNA, leading to a reduction in the metastasis-related FOXM1-S variant. In conclusion, our findings demonstrate that m6A-dependent alternative splicing mediated by HNRNPC is essential for lymphatic metastasis in CCa, potentially providing novel clinical markers and therapeutic strategies for patients with advanced CCa.

Senescent lung-resident mesenchymal stem cells drive pulmonary fibrogenesis through FGF-4/FOXM1 axis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is an age-related disease featured with abnormal fibrotic response and compromised lung function. Cellular senescence is now considered as an essential driving mechanism for IPF. Given the poor knowledge of the mechanisms underpinning IPF progression, understanding the cellular processes and molecular pathways is critical for developing effective therapies of IPF.

METHODS

Lung fibrosis was induced using bleomycin in C57BL/6 mice. Cellular senescence was measured by immunofluorescence. The effects of FGF-4 on fibroblast activation markers and signaling molecules were assessed with western blot and qPCR.

RESULTS

We demonstrated elevated abundance of senescent mesenchymal stem cells (MSCs) in IPF lung tissues, which was tightly correlated with the severity of pulmonary fibrosis in vivo. In addition, senescent MSCs could effectively induce the phenotype of pulmonary fibrosis both in vitro and in vivo. To further confirm how senescent MSCs regulate IPF progression, we demonstrate that FGF-4 is significantly elevated in senescent MSCs, which can induce the activation of pulmonary fibroblasts. In vitro, FGF-4 can activate Wnt signaling in a FOXM1-dependent manner. Inhibition of FOXM1 via thiostrepton effectively impairs FGF-4-induced activation of pulmonary fibroblast and dramatically suppresses the development of pulmonary fibrosis.

CONCLUSION

These findings reveal that FGF-4 plays a crucial role in senescent MSCs-mediated pulmonary fibrogenesis, and suggests that strategies aimed at deletion of senescent MSCs or blocking the FGF-4/FOXM1 axis could be effective in the therapy of IPF.

Transcriptional Levels of Intercellular Junction Proteins in an Alveolar Epithelial Cell Line Exposed to Irradiation or Bleomycin

We performed a comparative study of the effects of X-ray irradiation and bleomycin on the mRNA levels of E-cadherin and tight junction proteins (claudin-3, claudin-4, claudin-18, ZO-2, and occludin) in an alveolar epithelial cell line L2. Irradiation decreased claudin-4 levels and increased occludin levels, while the levels of other mRNAs remained unchanged. Bleomycin increased the expression levels of all proteins examined except claudin-3. Irradiation and bleomycin have different effects on the expression level of intercellular junction proteins, indicating different reactions triggered in alveolar epithelial cells and a great prospects of further comparative studies.

Invasive FoxM1 phosphorylated by PLK1 induces the polarization of tumor-associated macrophages to promote immune escape and metastasis, amplified by IFITM1

BACKGROUND

Understanding the mechanism behind immune cell plasticity in cancer metastasis is crucial for identifying key regulators. Previously we found that mitotic factors regulate epithelial-mesenchymal transition, but how these factors convert to metastatic players in the tumor microenvironment (TME) is not fully understood.

METHODS

The clinical importance of mitotic factors was analyzed by heatmap analysis, a KM plot, and immunohistochemistry in lung adenocarcinoma (LUAD) patients. Immunoprecipitation, LC-MS/MS, kinase assay, and site-directed mutagenesis were performed for the interaction and phosphorylation. A tail-vein injection mouse model, Transwell-based 3D culture, microarray analysis, coculture with monocytes, and chromatin immunoprecipitation assays were used to elucidate the function of phosphorylated FoxM1 in metastasis of TME.

RESULTS

The phosphorylated FoxM1 at Ser25 by PLK1 acquires the reprogramming ability to stimulate the invasive traits in cancer and influence immune cell plasticity. This invasive form of p-FoxM1 upregulates the expression of IL1A/1B, VEGFA, and IL6 by direct activation, recruiting monocytes and promoting the polarization of M2d-like tumor-associated macrophages (TAMs). Upregulation of PD-L1 in LUAD having phosphomimetic FoxM1 facilitates immune evasion. In invasive LUAD with phosphomimetic FoxM1, IFITM1 is the most highly expressed through the activation of the STING-TBK1-IRF3 signaling, which enhances FoxM1-mediated signaling. Clinically, higher expression of FOXM1, PLK1, and IFITM1 is inversely correlated with the survival rate of advanced LUAD patients, providing a promising therapeutic strategy for the treatment of LUAD.

CONCLUSION

FoxM1-based therapy would be a potential therapeutic strategy for LUAD to reduce TAM polarization, immune escape, and metastasis, since FoxM1 functions as a genetic reprogramming factor reinforcing LUAD malignancy in the TME.

Tissue fibrosis induced by radiotherapy: current understanding of the molecular mechanisms, diagnosis and therapeutic advances

Cancer remains the leading cause of death around the world. In cancer treatment, over 50% of cancer patients receive radiotherapy alone or in multimodal combinations with other therapies. One of the adverse consequences after radiation exposure is the occurrence of radiation-induced tissue fibrosis (RIF), which is characterized by the abnormal activation of myofibroblasts and the excessive accumulation of extracellular matrix. This phenotype can manifest in multiple organs, such as lung, skin, liver and kidney. In-depth studies on the mechanisms of radiation-induced fibrosis have shown that a variety of extracellular signals such as immune cells and abnormal release of cytokines, and intracellular signals such as cGAS/STING, oxidative stress response, metabolic reprogramming and proteasome pathway activation are involved in the activation of myofibroblasts. Tissue fibrosis is extremely harmful to patients' health and requires early diagnosis. In addition to traditional serum markers, histologic and imaging tests, the diagnostic potential of nuclear medicine techniques is emerging. Anti-inflammatory and antioxidant therapies are the traditional treatments for radiation-induced fibrosis. Recently, some promising therapeutic strategies have emerged, such as stem cell therapy and targeted therapies. However, incomplete knowledge of the mechanisms hinders the treatment of this disease. Here, we also highlight the potential mechanistic, diagnostic and therapeutic directions of radiation-induced fibrosis.

DOCK2 Promotes Asthma Development by Eliciting Airway Epithelial-Mesenchymal Transition

Epithelial-mesenchymal transition (EMT) contributes to airway remodeling, a predominant feature of asthma. DOCK2 (dedicator of cytokinesis 2) is an innate immune signaling molecule involved in vascular remodeling. However, it is unknown if DOCK2 plays a role in airway remodeling during asthma development. In this study, we found that DOCK2 is highly induced in both normal human bronchial epithelial cells treated with house dust mite (HDM) extract and human asthmatic airway epithelium. DOCK2 is also upregulated by TGF-β1 (transforming growth factor β1) during EMT of human bronchial epithelial cells. Importantly, knockdown of DOCK2 inhibits, and overexpression of DOCK2 promotes, TGF-β1-induced EMT. Consistently, DOCK2 deficiency suppresses the EMT of airway epithelium, attenuates the subepithelial fibrosis, and improves pulmonary function in HDM-induced asthmatic lungs. These data suggest that DOCK2 plays an important role in EMT and asthma development. Mechanistically, DOCK2 interacts with transcription factor FoxM1 (forkhead box M1), which enhances FoxM1 binding to mesenchymal marker gene promoters and further promotes mesenchymal marker gene transcription and expression, leading to EMT. Taken together, our study identifies DOCK2 as a novel regulator for airway EMT in an HDM-induced asthma model, thus providing a potential therapeutic target for treatment of asthma.

Macrophage Implication in IPF: Updates on Immune, Epigenetic, and Metabolic Pathways

Idiopathic pulmonary fibrosis (IPF) is a lethal interstitial lung disease of unknown etiology with a poor prognosis. It is a chronic and progressive disease that has a distinct radiological and pathological pattern from common interstitial pneumonia. The use of immunosuppressive medication was shown to be completely ineffective in clinical trials, resulting in years of neglect of the immune component. However, recent developments in fundamental and translational science demonstrate that immune cells play a significant regulatory role in IPF, and macrophages appear to be among the most crucial. These highly plastic cells generate multiple growth factors and mediators that highly affect the initiation and progression of IPF. In this review, we will provide an update on the role of macrophages in IPF through a systemic discussion of various regulatory mechanisms involving immune receptors, cytokines, metabolism, and epigenetics.

FOXM1a Isoform of Oncogene FOXM1 Is a Tumor Suppressor Suppressed by hnRNP C in Oral Squamous Cell Carcinoma

FOXM1 is an oncogenic transcriptional factor and includes several isoforms generated by alternative splicing. Inclusion of alternative exon 9 produces FOXM1a, a transcriptionally inactive isoform. However, the role of FOXM1a in tumorigenesis remains unknown. In addition, the regulatory mechanisms of exon 9 splicing are also unclear. In the present study, we found that overexpression of FOXM1a significantly reduced cell proliferation and colony formation of oral squamous cell carcinoma (OSCC) cell proliferation in vitro. Importantly, OSCC cells with FOXM1a overexpression showed significantly slower tumor formation in nude mice. Moreover, we identified a U-rich exonic splicing suppressor (ESS) which is responsible for exon 9 skipping. Splicing factor heterogeneous nuclear ribonucleoprotein C (hnRNP C) can bind to the ESS and suppress exon 9 inclusion and FOXM1a expression. Silence of hnRNP C also significantly suppresses OSCC cell proliferation. HnRNP C is significantly co-expressed with FOXM1 in cancers. Our study uncovered a novel regulatory mechanism of oncogene FOXM1 expression in OSCC.

mRNA Levels of Epithelial and Mesenchymal Markers in Lung Epithelial Cell Lines

Background

Epithelial-mesenchymal transition (EMT) is an important physiologic process that determines the outcome of lung tissue healing after injury. Stimuli and molecular cascades inducing EMT lead to up-regulation of the mesenchymal-specific genes in the alveolar epithelial cells and to down-regulation of the genes coding for epithelial markers. Alveolar epithelial cell lines are commonly used as in vitro models to study processes occurring in the lung tissue. The aim of this study is to quantify and compare mRNA expression levels of epithelial and mesenchymal markers in a number of lung epithelial cell lines.

Methods

Lung epithelial cell lines L2, R3/1 and RLE-6TN were cultured. Repeated mRNA isolation, reverse transcription, and quantitative PCR with primers to epithelial (E-cadherin, occludin, and ZO-2) and mesenchymal (α-SMA, collagen III, and vimentin) markers were performed.

Results

First, our study revealed a higher level of epithelial transcripts in the RLE-6TN cell line compared to L2 and R3/1 cells. Secondly, we have found simultaneous mRNA expression of both epithelial (E-cadherin, occludin and ZO-2) and mesenchymal (α-SMA, collagen III and vimentin) markers in all cell lines studied.

Conclusions

Our data indicate that at the transcriptional level the L2, R3/1, and RLE-6TN cell lines are at one of the intermediate stages of EMT, which opens new possibilities for the study of EMT on cell lines. Determination of the direction of changes in epithelial and mesenchymal markers will make it possible to establish the factors responsible for both EMT and reverse mesenchymal-epithelial transition.

Long non-coding RNAs in non-small cell lung cancer: implications for EGFR-TKI resistance

Non-small cell lung cancer (NSCLC) is one of the most common types of malignant tumors as well as the leading cause of cancer-related deaths in the world. The application of epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitors (TKIs) has dramatically improved the prognosis of NSCLC patients who harbor EGFR mutations. However, despite an excellent initial response, NSCLC inevitably becomes resistant to EGFR-TKIs, leading to irreversible disease progression. Hence, it is of great significance to shed light on the molecular mechanisms underlying the EGFR-TKI resistance in NSCLC. Long non-coding RNAs (lncRNAs) are critical gene modulators that are able to act as oncogenes or tumor suppressors that modulate tumorigenesis, invasion, and metastasis. Recently, extensive evidence demonstrates that lncRNAs also have a significant function in modulating EGFR-TKI resistance in NSCLC. In this review, we present a comprehensive summary of the lncRNAs involved in EGFR-TKI resistance in NSCLC and focus on their detailed mechanisms of action, including activation of alternative bypass signaling pathways, phenotypic transformation, intercellular communication in the tumor microenvironment, competing endogenous RNAs (ceRNAs) networks, and epigenetic modifications. In addition, we briefly discuss the limitations and the clinical implications of current lncRNAs research in this field.

The therapeutic effect of exosomal lncRNA MSTRG.91634.7 on mitochondrial dysfunction during SiO2-induced lung fibrosis

Long-term silica (SiO₂) exposure led to irreversible lung fibrosis, in which epithelial-mesenchymal transition (EMT) played an essential role. A novel lncRNA MSTRG.91634.7 in the peripheral exosomes of silicosis patients was reported in our previous study, which could remold the pathological process of silicosis. However, whether its regulatory role on the development of silicosis was related to EMT process is unclear, and its mechanism remains to be further studied. In this study, up-regulating lncRNA MSTRG91634.7 restricted SiO₂-activated EMT and restored mitochondrial homeostasis binding to PINK1 in vitro. Moreover, overexpressing PINK1 could inhibit SiO₂-activated EMT in pulmonary inflammation and fibrosis in mice. Meanwhile, PINK1 contributed to restoring the SiO₂-induced mitochondrial dysfunction in mice lung. Our results revealed that exosomal lncRNA MSTRG.91634.7 from macrophages could restore mitochondrial homeostasis to restrict the SiO₂-activated EMT by binding to PINK1 during pulmonary inflammation and fibrosis due to SiO₂ exposure.

FOXM1: Functional Roles of FOXM1 in Non-Malignant Diseases

Forkhead box (FOX) proteins are a wing-like helix family of transcription factors in the DNA-binding region. By mediating the activation and inhibition of transcription and interactions with all kinds of transcriptional co-regulators (MuvB complexes, STAT3, β-catenin, etc.), they play significant roles in carbohydrate and fat metabolism, biological aging and immune regulation, development, and diseases in mammals. Recent studies have focused on translating these essential findings into clinical applications in order to improve quality of life, investigating areas such as diabetes, inflammation, and pulmonary fibrosis, and increase human lifespan. Early studies have shown that forkhead box M1 (FOXM1) functions as a key gene in pathological processes in multiple diseases by regulating genes related to proliferation, the cell cycle, migration, and apoptosis and genes related to diagnosis, therapy, and injury repair. Although FOXM1 has long been studied in relation to human diseases, its role needs to be elaborated on. FOXM1 expression is involved in the development or repair of multiple diseases, including pulmonary fibrosis, pneumonia, diabetes, liver injury repair, adrenal lesions, vascular diseases, brain diseases, arthritis, myasthenia gravis, and psoriasis. The complex mechanisms involve multiple signaling pathways, such as WNT/β-catenin, STAT3/FOXM1/GLUT1, c-Myc/FOXM1, FOXM1/SIRT4/NF-κB, and FOXM1/SEMA3C/NRP2/Hedgehog. This paper reviews the key roles and functions of FOXM1 in kidney, vascular, lung, brain, bone, heart, skin, and blood vessel diseases to elucidate the role of FOXM1 in the development and progression of human non-malignant diseases and makes suggestions for further research.

Mesenchymal cells in the Lung: Evolving concepts and their role in fibrosis

Mesenchymal cells in the lung are crucial during development, but also contribute to the pathogenesis of fibrotic disorders, including idiopathic pulmonary fibrosis (IPF), the most common and deadly form of fibrotic interstitial lung diseases. Originally thought to behave as supporting cells for the lung epithelium and endothelium with a singular function of producing basement membrane, mesenchymal cells encompass a variety of cell types, including resident fibroblasts, lipofibroblasts, myofibroblasts, smooth muscle cells, and pericytes, which all occupy different anatomic locations and exhibit diverse homeostatic functions in the lung. During injury, each of these subtypes demonstrate remarkable plasticity and undergo varying capacity to proliferate and differentiate into activated myofibroblasts. Therefore, these cells secrete high levels of extracellular matrix (ECM) proteins and inflammatory cytokines, which contribute to tissue repair, or in pathologic situations, scarring and fibrosis. Whereas epithelial damage is considered the initial trigger that leads to lung injury, lung mesenchymal cells are recognized as the ultimate effector of fibrosis and attempts to better understand the different functions and actions of each mesenchymal cell subtype will lead to a better understanding of why fibrosis develops and how to better target it for future therapy. This review summarizes current findings related to various lung mesenchymal cells as well as signaling pathways, and their contribution to the pathogenesis of pulmonary fibrosis.

Epigenetic Control of Cancer Cell Proliferation and Cell Cycle Progression by HNRNPK via Promoting Exon 4 Inclusion of Histone Code Reader SPIN1

Heterogeneous nuclear ribonucleoprotein K (HNRNPK, hnRNP K), a multifunctional RNA/DNA binding protein, mainly regulates transcription, translation and RNA splicing, and then plays oncogenic roles in many cancers. However, the related mechanisms remain largely unknown. Here, we found that HNRNPK can partially epigenetically regulate cancer cell proliferation via increasing transcription and exon 4-inclusion of SPIN1, an important oncogenic histone code reader. This exon 4 skipping event of SPIN1 generates a long non-coding RNA, followed by the downregulation of SPIN1 protein. SPIN1 is one of the most significantly co-expressed genes of HNRNPK in thirteen TCGA cancers. Our further studies revealed HNRNPK knockdown significantly inhibited cell growth and cell cycle progression in oral squamous cell carcinoma (OSCC) cells and promoted cell apoptosis. Overexpression of SPIN1 was able to partially rescue the growth inhibition triggered by HNRNPK knockdown. Moreover, CCND1 (Cyclin D1), a key cell cycle regulator and oncogene, epigenetically up-regulated by SPIN1, was also positively regulated by HNRNPK. In addition, we discovered that HNRNPK promoted SPIN1 exon 4 inclusion by interacting with an intronic splicing enhancer in intron 4. Collectively, our study suggests a novel epigenetic regulatory pathway of HNRNPK in OSCC, mediated by controlling the transcription activity and alternative splicing of SPIN1 gene.

Monophosphoryl lipid A ameliorates radiation-induced lung injury by promoting the polarization of macrophages to the M1 phenotype

Background

Radiation-induced lung injury (RILI) often occurs during clinical chest radiotherapy and acute irradiation from accidental nuclear leakage. This study explored the role of monophosphoryl lipid A (MPLA) in RILI.

Materials and Methods

The entire thoracic cavity of C57BL/6N mice was irradiated at 20 Gy with or without pre-intragastric administration of MPLA. HE staining, Masson trichrome staining, and TUNEL assay were used to assess lung tissue injury after treatment. The effect of irradiation on the proliferation of MLE-12 cells was analyzed using the Clonogenic assay. The effect of MPLA on the apoptosis of MLE-12 cells was analyzed using flow cytometry. Expression of γ-H2AX and epithelial-mesenchymal transition (EMT) markers in MLE-12 cells was detected by immunofluorescence and Western blot, respectively.

Results

MPLA attenuated early pneumonitis and late pulmonary fibrosis after thoracic irradiation and reversed radiation-induced EMT in C57 mice. MPLA further promoted proliferation and inhibited apoptosis of irradiated MLE-12 cells in vitro. Mechanistically, the radioprotective effect of MPLA was mediated by exosomes secreted by stimulated macrophages. Macrophage-derived exosomes modulated DNA damage in MLE-12 cells after irradiation. MPLA promoted the polarization of RAW 264.7 cells to the M1 phenotype. The exosomes secreted by M1 macrophages suppressed EMT in MLE-12 cells after irradiation.

Conclusion

MPLA is a novel treatment strategy for RILI. Exosomes derived from macrophages are key to the radioprotective role of MPLA in RILI.

Peripheral vascular remodeling during ischemia

About 230 million people worldwide suffer from peripheral arterial disease (PAD), and the prevalence is increasing year by year. Multiple risk factors, including smoking, dyslipidemia, diabetes, and hypertension, can contribute to the development of PAD. PAD is typically characterized by intermittent claudication and resting pain, and there is a risk of severe limb ischemia, leading to major adverse limb events, such as amputation. Currently, a major progress in the research field of the pathogenesis of vascular remodeling, including atherosclerosis and neointima hyperplasia has been made. For example, the molecular mechanisms of endothelial dysfunction and smooth muscle phenotype switching have been described. Interestingly, a series of focused studies on fibroblasts of the vessel wall has demonstrated their impact on smooth muscle proliferation and even endothelial function via cell-cell communications. In this review, we aim to focus on the functional changes of peripheral arterial cells and the mechanisms of the pathogenesis of PAD. At the same time, we summarize the progress of the current clinical treatment and potential therapeutic methods for PAD and shine a light on future perspectives.

Lung Pneumonitis and Fibrosis in Cancer Therapy: A Review on Cellular and Molecular Mechanisms

Fibrosis and pneumonitis are the most important side effects of lung tissue following cancer therapy. Radiotherapy and chemotherapy by some drugs, such as bleomycin, can induce pneumonitis and fibrosis. Targeted therapy and immunotherapy also may induce pneumonitis and fibrosis to a lesser extent compared to chemotherapy and radiotherapy. Activation of lymphocytes by immunotherapy or infiltration of inflammatory cells such as macrophages, lymphocytes, neutrophils, and mast cells following chemo/radiation therapy can induce pneumonitis. Furthermore, the polarization of macrophages toward M2 cells and the release of anti-inflammatory cytokines stimulate fibrosis. Lung fibrosis and pneumonitis may also be potentiated by some other changes such as epithelial-mesenchymal transition (EMT), oxidative stress, reduction/oxidation (redox) responses, renin-angiotensin system, and the upregulation of some inflammatory mediators such as a nuclear factor of kappa B (NF-κB), inflammasome, cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS). Damages to the lung vascular system and the induction of hypoxia also can induce pulmonary injury following chemo/radiation therapy. This review explains various mechanisms of the induction of pneumonitis and lung fibrosis following cancer therapy. Furthermore, the targets and promising agents to mitigate lung fibrosis and pneumonitis will be discussed.

Human alveolar progenitors generate dual lineage bronchioalveolar organoids

Mechanisms of epithelial renewal in the alveolar compartment remain incompletely understood. To this end, we aimed to characterize alveolar progenitors. Single-cell RNA-sequencing (scRNA-seq) analysis of the HTII-280⁺/EpCAM⁺ population from adult human lung revealed subclusters enriched for adult stem cell signature (ASCS) genes. We found that alveolar progenitors in organoid culture in vitro show phenotypic lineage plasticity as they can yield alveolar or bronchial cell-type progeny. The direction of the differentiation is dependent on the presence of the GSK-3β inhibitor, CHIR99021. By RNA-seq profiling of GSK-3β knockdown organoids we identified additional candidate target genes of the inhibitor, among others FOXM1 and EGF. This gives evidence of Wnt pathway independent regulatory mechanisms of alveolar specification. Following influenza A virus (IAV) infection organoids showed a similar response as lung tissue explants which confirms their suitability for studies of sequelae of pathogen-host interaction.

Wnt Site Signaling Inhibitor Secreted Frizzled‐Related Protein 3 Protects Mitral Valve Endothelium From Myocardial Infarction–Induced Endothelial‐to‐Mesenchymal Transition

Background

The onset and mechanisms of endothelial‐to‐mesenchymal transition (EndMT) in mitral valve (MV) leaflets following myocardial infarction (MI) are unknown, yet these events are closely linked to stiffening of leaflets and development of ischemic mitral regurgitation. We investigated whether circulating molecules present in plasma within days after MI incite EndMT in MV leaflets.

Methods and Results

We examined the onset of EndMT in MV leaflets from 9 sheep with inferior MI, 8 with sham surgery, and 6 naïve controls. Ovine MVs 8 to 10 days after inferior MI displayed EndMT, shown by increased vascular endothelial cadherin/α‐smooth muscle actin–positive cells. The effect of plasma on EndMT in MV endothelial cells (VECs) was assessed by quantitative polymerase chain reaction, migration assays, and immunofluorescence. In vitro, post‐MI plasma induced EndMT marker expression and enhanced migration of mitral VECs; sham plasma did not. Analysis of sham versus post‐MI plasma revealed a significant drop in the Wnt signaling antagonist sFRP3 (secreted frizzled‐related protein 3) in post‐MI plasma. Addition of recombinant sFRP3 to post‐MI plasma reversed its EndMT‐inducing effect on mitral VECs. RNA‐sequencing analysis of mitral VECs exposed to post‐MI plasma showed upregulated FOXM1 (forkhead box M1). Blocking FOXM1 reduced EndMT transcripts in mitral VECs treated with post‐MI plasma. Finally, FOXM1 induced by post‐MI plasma was downregulated by sFRP3.

Conclusions

Reduced sFRP3 in post‐MI plasma facilitates EndMT in mitral VECs by increasing the transcription factor FOXM1. Restoring sFRP3 levels or inhibiting FOXM1 soon after MI may provide a novel strategy to modulate EndMT in the MV to prevent ischemic mitral regurgitation and heart failure.

Inflammogenic effect of polyacrylic acid in rat lung following intratracheal instillation

Background

Some organic chemicals are known to cause allergic disorders such as bronchial asthma and hypersensitivity pneumonitis, and it has been considered that they do not cause irreversible pulmonary fibrosis. It has recently been reported, however, that cross-linked acrylic acid-based polymer, an organic chemical, might cause serious interstitial lung diseases, including pulmonary fibrosis. We investigated whether or not intratracheal instillation exposure to cross-linked polyacrylic acid (CL-PAA) can cause lung disorder in rats.

Methods

Male F344 rats were intratracheally instilled with dispersed CL-PAA at low (0.2 mg/rat) and high (1.0 mg/rat) doses, and were sacrificed at 3 days, 1 week, 1 month, 3 months and 6 months after exposure to examine inflammatory and fibrotic responses and related gene expressions in the lungs. Rat lungs exposed to crystalline silica, asbestos (chrysotile), and NiO and CeO2 nanoparticles were used as comparators.

Results

Persistent increases in total cell count, neutrophil count and neutrophil percentage, and in the concentration of the cytokine-induced neutrophil chemoattractant (CINC)-1, CINC-2 and C-X-C motif chemokine 5 (CXCL5), which correlated with lung tissue gene expression, were observed in bronchoalveolar lavage fluid (BALF) from 3 days until at least 1 month following CL-PAA intratracheal instillation. Persistent increases in heme oxygenase-1 (HO-1) in the lung tissue were also observed from 3 days to 6 months after exposure. Histopathological findings of the lungs demonstrated that extensive inflammation at 3 days was greater than that in exposure to silica, NiO nanoparticles and CeO2 nanoparticles, and equal to or greater than that in asbestos (chrysotile) exposure, and the inflammation continued until 1 month. Fibrotic changes also progressed after 1 month postexposure.

Conclusion

Our results suggested that CL-PAA potentially causes strong neutrophil inflammation in the rat and human lung.

miR-138 inhibits epithelial-mesenchymal transition in silica-induced pulmonary fibrosis by regulating ZEB2

Silica dust is a common pollutant in the occupational environment, such as coal mines. Inhalation of silica dust can cause progressive pulmonary fibrosis and then silicosis. Silicosis is still one of the most harmful occupational diseases in the world, so the study of its pathogenesis is necessary for the treatment of silicosis. In this study, we constructed a mouse model of pulmonary fibrosis via intratracheal instillation of silica particles and identified the decreased expression of miR-138 in fibrotic lung tissues of mice. Moreover, the overexpression of miR-138 retarded the process of epithelial-mesenchymal transition (EMT) in a mouse model of silica particles exposure and epithelial cells stimulated by silica particles. Further studies showed that ZEB2 was one of the potential targets of miR-138, and the up-regulation of miR-138 reduced ZEB2 levels in mouse lung tissues and in epithelial cells. We next found that the expression levels of ɑ-SMA and Vimentin were significantly increased and E-cadherin levels were decreased after transfection with miR-138 inhibitor in epithelial cells. However, these effects were abated by the knockdown of ZEB2. Consistently, the increased migration ability of epithelial cells by miR-138 inhibitor transfection was also reversed by the knockdown of ZEB2. Collectively, we revealed that miR-138 significantly targeted ZEB2, thus inhibited the EMT process and mitigated the development of pulmonary fibrosis. miR-138 may be a potential target for the treatment of pulmonary fibrosis.

Silencing of long non-coding RNA KCNQ1OT1 alleviates LPS-induced lung injury by regulating the miR-370-3p/FOXM1 axis in childhood pneumonia

Purpose

Long non-coding RNAs (lncRNAs) play important roles in the development of pneumonia. We aimed to explore the role of the lncRNA KCNQ1OT1 in pneumonia and its underlying mechanisms.

Methods

The expression of KCNQ1OT1, FOXM1, and miR-370-3p was detected in the serum of 24 children with pneumonia and in 24 healthy controls. Normal human embryonic lung-derived diploid fibroblasts (WI-38 cells) were stimulated with LPS (10 μg/mL) to simulate the cellular model of pneumonia, and cell viability, apoptosis, and inflammation were analysed. Dual luciferase reporter and/or RNA binding protein immunoprecipitation assays were performed to test the relationship between miR-370-3p and KCNQ1OT1/FOXM1. Mice were intratracheally administered LPS (5 mg/kg) to induce an in vivo model of pneumonia, and pathological injury and inflammation were analysed.

Results

The expression of KCNQ1OT1 and FOXM1 was up-regulated, and miR-370-3p was down-regulated in the serum of children with pneumonia, LPS-treated WI-38 cells, and in lung tissues of LPS-treated mice. Silencing of KCNQ1OT1 or overexpression of miR-370-3p suppressed cell apoptosis and inflammation and facilitated cell viability in LPS-treated WI-38 cells. KCNQ1OT1 directly targets miR-370-3p and negatively regulates its expression. FOXM1 was targeted by miR-370-3p and negatively modulated by miR-370-3p. In addition, silencing of KCNQ1OT1 mitigated LPS-induced lung injury and inflammation in mice. The protective effects of KCNQ1OT1 silencing in LPS-treated WI-38 cells and mice were reversed by silencing of miR-370-3p or overexpression of FOXM1.

Conclusion

Silencing of KCNQ1OT1 alleviates LPS-induced lung injury by regulating the miR-370-3p/FOXM1 axis in pneumonia.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01609-0.

The Anticancer Effects of FDI-6, a FOXM1 Inhibitor, on Triple Negative Breast Cancer

Triple-negative breast cancer (TNBC) presents an important clinical challenge, as it does not respond to endocrine therapies or other available targeting agents. FOXM1, an oncogenic transcriptional factor, has reported to be upregulated and associated with poor clinical outcomes in TNBC patients. In this study, we investigated the anti-cancer effects of FDI-6, a FOXM1 inhibitor, as well as its molecular mechanisms, in TNBC cells. Two TNBC cell lines, MDA-MB-231 and HS578T, were used in this study. The anti-cancer activities of FDI-6 were evaluated using various 2D cell culture assays, including Sulforhodamine B (SRB), wound healing, and transwell invasion assays together with 3D spheroid assays, mimicking real tumour structural properties. After treatment with FDI-6, the TNBC cells displayed a significant inhibition in cell proliferation, migration, and invasion. Increased apoptosis was also observed in the treated cells. In addition, we found that FDI-6 lead to the downregulation of FOXM1 and its key oncogenic targets, including CyclinB1, Snail, and Slug. Interestingly, we also found that the FDI-6/Doxorubicin combination significantly enhanced the cytotoxicity and apoptotic properties, suggesting that FDI-6 might improve chemotherapy treatment efficacy and reduce unwanted side effects. Altogether, FDI-6 exhibited promising anti-tumour activities and could be developed as a newly effective treatment for TNBC.

Inhibiting HDAC3 (Histone Deacetylase 3) Aberration and the Resultant Nrf2 (Nuclear Factor Erythroid-Derived 2-Related Factor-2) Repression Mitigates Pulmonary Fibrosis

[Figure: see text].

foxm1 Modulates Cell Non-Autonomous Response in Zebrafish Skeletal Muscle Homeostasis

foxm1 is a master regulator of the cell cycle, contributing to cell proliferation. Recent data have shown that this transcription factor also modulates gene networks associated with other cellular mechanisms, suggesting non-proliferative functions that remain largely unexplored. In this study, we used CRISPR/Cas9 to disrupt foxm1 in the zebrafish terminally differentiated fast-twitching muscle cells. foxm1 genomic disruption increased myofiber death and clearance. Interestingly, this contributed to non-autonomous satellite cell activation and proliferation. Moreover, we observed that Cas9 expression alone was strongly deleterious to muscle cells. Our report shows that foxm1 modulates a muscle non-autonomous response to myofiber death and highlights underreported toxicity to high expression of Cas9 in vivo.

Mechanism of Dandelion Sterol in Treating Pulmonary Fibrosis Through Transforming Growth Factor-β Signaling Pathway

Background: The paper aimed to elucidate the molecular mechanism of Dandelion sterol in the treatment of pulmonary fibrosis, to study its effect on EMT of lung epithelial cells, and to find its target and downstream signaling pathways. Material and methods: The effects of Dandelion sterol on parathyroid (PQ)-induced EMT in lung epithelial cells were studied by immunofluorescence method. Immunohistochemistry and western-blot methods were used to verify that Dandelion sterol inhibited TGF-β1-induced EMT at the cellular level in animals, demonstrating that Dandelion sterol targets TGF-β1 to exert an anti-pulmonary fibrosis effect. Results: Dandelion sterol significantly inhibited PQ-induced migration and invasion of lung epithelial cells, and also inhibited the induced EMT. Dandelion sterol had a proper binding activity with the lung fibrosis-inducing factor TGF-β1. Dandelion sterol inhibited the TGF-β1-induced EMT process, and acted to treat pulmonary fibrosis by inhibiting the TGF-β1/Smad3 signaling pathway. Conclusion: Dandelion sterol can inhibit the pulmonary fibrosis by inhibiting the EMT process of lung epithelial cells through targeting the TGF- β1/Smad signaling pathway.

Applications and therapeutic mechanisms of action of mesenchymal stem cells in radiation-induced lung injury

Radiation-induced lung injury (RILI) is one of the most common complications associated with radiotherapy, characterized by early-stage radiation pneumonia and subsequent radiation pulmonary fibrosis. However, effective therapeutic strategies for RILI are currently lacking. Recently, an increasing number of studies reported that mesenchymal stem cells (MSCs) can enhance the regeneration of damaged tissue, modulate the inflammatory response, reduce the levels of fibrotic cytokines and reactive oxygen species, and inhibit epithelial-mesenchymal transformation. Interestingly, MSCs can also exert immunosuppressive effects, which highlights a new potential therapeutic activity of MSCs for managing RILI. Here, we reviewed the potential applications and therapeutic mechanisms of action of MSCs in RILI, which will represent a good compendium of information for researchers in this field.

Ginsenoside Rg3 inhibits pulmonary fibrosis by preventing HIF-1α nuclear localisation

Background

Excessive fibroblast proliferation during pulmonary fibrosis leads to structural abnormalities in lung tissue and causes hypoxia and cell injury. However, the mechanisms and effective treatment are still limited.

Methods

In vivo, we used bleomycin to induce pulmonary fibrosis in mice. IHC and Masson staining were used to evaluate the inhibitory effect of ginsenoside Rg3 in pulmonary fibrosis. In vitro, scanning electron microscopy, transwell and wound healing were used to evaluate the cell phenotype of LL 29 cells. In addition, biacore was used to detect the binding between ginsenoside Rg3 and HIF-1α.

Results

Here, we found that bleomycin induces the activation of the HIF-1α/TGFβ1 signalling pathway and further enhances the migration and proliferation of fibroblasts through the epithelial mesenchymal transition (EMT). In addition, molecular docking and biacore results indicated that ginsenoside Rg3 can bind HIF-1α. Therefore, Ginsenoside Rg3 can slow down the progression of pulmonary fibrosis by inhibiting the nuclear localisation of HIF-1α.

Conclusions

This finding suggests that early targeted treatment of hypoxia may have potential value in the treatment of pulmonary fibrosis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-021-01426-5.

FOXM1 and Cancer: Faulty Cellular Signaling Derails Homeostasis

Forkhead box transcription factor, FOXM1 is implicated in several cellular processes such as proliferation, cell cycle progression, cell differentiation, DNA damage repair, tissue homeostasis, angiogenesis, apoptosis, and redox signaling. In addition to being a boon for the normal functioning of a cell, FOXM1 turns out to be a bane by manifesting in several disease scenarios including cancer. It has been given an oncogenic status based on several evidences indicating its role in tumor development and progression. FOXM1 is highly expressed in several cancers and has also been implicated in poor prognosis. A comprehensive understanding of various aspects of this molecule has revealed its role in angiogenesis, invasion, migration, self- renewal and drug resistance. In this review, we attempt to understand various mechanisms underlying FOXM1 gene and protein regulation in cancer including the different signaling pathways, post-transcriptional and post-translational modifications. Identifying crucial molecules associated with these processes can aid in the development of potential pharmacological approaches to curb FOXM1 mediated tumorigenesis.

Mesenchymal Stem Cells for Mitigating Radiotherapy Side Effects

Radiation therapy for cancers also damages healthy cells and causes side effects. Depending on the dosage and exposure region, radiotherapy may induce severe and irreversible injuries to various tissues or organs, especially the skin, intestine, brain, lung, liver, and heart. Therefore, promising treatment strategies to mitigate radiation injury is in pressing need. Recently, stem cell-based therapy generates great attention in clinical care. Among these, mesenchymal stem cells are extensively applied because it is easy to access and capable of mesodermal differentiation, immunomodulation, and paracrine secretion. Here, we summarize the current attempts and discuss the future perspectives about mesenchymal stem cells (MSCs) for mitigating radiotherapy side effects.

Scarred Lung. An Update on Radiation-Induced Pulmonary Fibrosis

Radiation-induced pulmonary fibrosis is a common severe long-time complication of radiation therapy for tumors of the thorax. Current therapeutic options used in the clinic include only supportive managements strategies, such as anti-inflammatory treatment using steroids, their efficacy, however, is far from being satisfactory. Recent studies have demonstrated that the development of lung fibrosis is a dynamic and complex process, involving the release of reactive oxygen species, activation of Toll-like receptors, recruitment of inflammatory cells, excessive production of nitric oxide and production of collagen by activated myofibroblasts. In this review we summarized the current state of knowledge on the pathophysiological processes leading to the development of lung fibrosis and we also discussed the possible treatment options.

FoxM1 promotes Wnt/β-catenin pathway activation and renal fibrosis via transcriptionally regulating multi-Wnts expressions

The activation of Wnt/β‐catenin pathway plays a pivotal role in promoting renal fibrosis. The activation of Wnt/β‐catenin pathway relies on the binding of Wnts to Frizzled receptors on cell membrane. However, the factor regulating Wnts production remains unclear. Here, we demonstrated that transcriptional factor FoxM1 was significantly increased in obstructed kidneys and patients' kidneys with fibrosis. The up‐regulation of FoxM1 mainly distributed in tubular epithelial cells. Pharmacological inhibition of FoxM1 down‐regulated multi‐Wnts elevation in UUO mice and attenuated renal fibrosis. In cultured renal tubular epithelial cells, overexpression of FoxM1 promoted 8 Wnts expression, while knock‐down on FoxM1‐suppressed multi‐Wnts including Wnt1, Wnt2b and Wnt3 expression induced by Ang II. Chromatin immunoprecipitation PCR confirmed that FoxM1 bound to Wnt1, Wnt2b, Wnt3 promoters and luciferase assay further identified that the transcriptions of Wnt1, Wnt2b and Wnt3 were regulated by FoxM1. Thus, our findings show that multi‐Wnt family members were regulated by transcriptional factor FoxM1. FoxM1 might be a key switch for activating β‐catenin pathway and renal fibrosis. Therefore, FoxM1 might be a potential therapeutic target in manipulating renal fibrosis.

Silencing of CASC8 inhibits non-small cell lung cancer cells function and promotes sensitivity to osimertinib via FOXM1

In a meta-analysis, the long noncoding RNA cancer susceptibility candidate 8 (CASC8) was found to be a cancer susceptibility gene closely related to lung cancer, but its functions in lung cancer are unknown. In the Cancer Genome Atlas database, the expression of CASC8 was significantly higher in non-small cell lung cancer than in adjacent normal tissues, and high expression of CASC8 was associated with poor prognosis in patients with lung adenocarcinoma. Silencing CASC8 inhibited proliferation, migration, and invasion in non-small cell lung cancer cell lines. Silencing CASC8 also promoted sensitivity to osimertinib through Forkhead box M1 (FOXM1). Therefore, this pathway can be exploited in patients with lung cancer resistant to targeted therapies. Our study revealed for the first time that silencing CASC8 inhibited the proliferation, migration, and invasion of non-small cell lung cancer cells and promoted their sensitivity to osimertinib, suggesting that CASC8 is closely related to the occurrence and development of non-small cell lung cancer. This may provide insight into mechanisms of treatment for non-small cell lung cancer.

MiRNA-155-5p inhibits epithelium-to-mesenchymal transition (EMT) by targeting GSK-3β during radiation-induced pulmonary fibrosis

Radiation-induced pulmonary fibrosis (RIPF) is a major lung complication in using radiotherapy to treat thoracic diseases. MicroRNAs (miRNAs) are reported to be the therapeutic targets for many diseases. However, the miRNAs involved in the pathogenesis of RIPF are rarely studied as potential therapeutic targets. Alveolar epithelial cells participate in RIPF formation by undergoing epithelial-mesenchymal transition (EMT). Here we demonstrated the critical role of miR-155-5p in radiation-induced EMT and RIPF. Using the previously established EMT cell model, we found that miR-155-5p was significantly down-regulated through high-throughput sequencing. Irradiation could decrease the expression of miR-155-5p in intro and in vivo, and it was inversely correlated to RIPF formation. Ectopic miR-155-5p expression inhibited radiation-induced-EMT in vitro and in vivo. Knockdown of glycogen synthase kinase-3β (GSK-3β), the functional target of miR-155-5p, reversed the induction of EMT and enhanced the phosphorylation of p65, a subunit of NF-κB, which were mediated by the down-regulation of miR-155-5p. Moreover, our finding demonstrated that ectopic miR-155-5p expression alleviated RIPF in mice by the GSK-3β/NF-κB pathway. Thus, radiation downregulates miR-155-5p in alveolar epithelial cells that induces EMT, which contributes to RIPF using GSK-3β/NF-κB pathway. Our observation provides further understanding on the regulation of RIPF and identifies potential therapeutic targets.

Mucosa-Associated Lymphoid Tissue Lymphoma Translocation 1 Inhibitor as a Novel Therapeutic Tool for Lung Injury

Pulmonary fibrosis is a progressive disease characterized by lung remodeling due to excessive deposition of extracellular matrix. In this study, the bleomycin experimental model of pulmonary fibrosis was employed to investigate the anti-fibrotic and immunomodulatory activity of the inhibition of MALT1 protease activity. Mice received a single intra-tracheal administration of bleomycin (1 mg/kg) in the presence or absence of MI-2, a selective MALT1 inhibitor, (a dose of 30 mg/kg administered intra-peritoneally 1 h after bleomycin and daily until the end of the experiment). Seven days after bleomycin instillation mice were sacrificed and bronchoalveolar lavage fluid analysis, measurement of collagen content in the lung, histology, molecular analysis and immunohistochemistry were performed. To evaluate mortality and body weight gain a subset of mice was administered daily with MI-2 for 21 days. Mice that received MI-2 showed decreased weight loss and mortality, inflammatory cells infiltration, cytokines overexpression and tissue injury. Moreover, biochemical and immunohistochemical analysis displayed that MI-2 was able to modulate the excessive production of reactive oxygen species and the inflammatory mediator upregulation induced by bleomycin instillation. Additionally, MI-2 demonstrated anti-fibrotic activity by reducing transforming growth factor-β (TGF-β), α-smooth muscle actin (α-SMA) and receptor associated factor 6 (TRAF6) expression. The underlying mechanisms for the protective effect of MI-2 bleomycin induced pulmonary fibrosis may be attributed to its inhibition on NF-κB pathway. This is the first report showing the therapeutic role of MALT1 inhibition in a bleomycin model of pulmonary fibrosis, thus supporting further preclinical and clinical studies.

Regulatory T Cells: An Emerging Player in Radiation-Induced Lung Injury

Regulatory T cells (Tregs), which have long been recognized as essential regulators of both inflammation and autoimmunity, also impede effective antitumor immune response due to their immunosuppressive properties. Combined radiotherapy and immunotherapeutic interventions focusing on the removal of Tregs have recently garnered interest as a promising strategy to reverse immunosuppression. Meanwhile, Tregs are emerging as a key player in the pathogenesis of radiation-induced lung injury (RILI), a frequent and potentially life-threatening complication of thoracic radiotherapy. Recognition of the critical role of Tregs in RILI raises the important question of whether radiotherapy combined with Treg-targeting immunotherapy offers any beneficial effects in the protection of normal lung tissue. This present review focuses on the contributions of Tregs to RILI, with particular emphasis on the suspected differential role of Tregs in the pneumonitic phase and fibrotic phase of RILI. We also introduce recent progress on the potential mechanisms by which Tregs modulate RILI and the crosstalk among Tregs, other infiltrating T cells, fibrocytes, and resident epithelial cells driving disease pathogenesis. Finally, we discuss whether Tregs also hold promise as a potential target for immunotherapeutic interventions for RILI.

Calpain 9 as a therapeutic target in TGFβ-induced mesenchymal transition and fibrosis

Fibrosis is a common pathologic outcome of chronic disease resulting in the replacement of normal tissue parenchyma with a collagen-rich extracellular matrix produced by myofibroblasts. Although the progenitor cell types and cellular programs giving rise to myofibroblasts through mesenchymal transition can vary between tissues and diseases, their contribution to fibrosis initiation, maintenance, and progression is thought to be pervasive. Here, we showed that the ability of transforming growth factor-β (TGFβ) to efficiently induce myofibroblast differentiation of cultured epithelial cells, endothelial cells, or quiescent fibroblasts is dependent on the induced expression and activity of dimeric calpains, a family of non-lysosomal cysteine proteases that regulate a variety of cellular events through posttranslational modification of diverse substrates. siRNA-based gene silencing demonstrated that TGFβ-induced mesenchymal transition of a murine breast epithelial cell line was dependent on induction of expression of calpain 9 (CAPN9), an isoform previously thought to be restricted to the gastrointestinal tract. Mice lacking functional CAPN9 owing to biallelic targeting of Capn9 were viable and fertile but showed overt protection from bleomycin-induced lung fibrosis, carbon tetrachloride-induced liver fibrosis, and angiotensin II-induced cardiac fibrosis and dysfunction. A predicted loss-of-function allele of CAPN9 is common in Southeast Asia, with the frequency of homozygosity matching the prediction of Hardy-Weinberg equilibrium. Together with the highly spatially restricted pattern of CAPN9 expression under physiologic circumstances and the heartiness of the murine knockout, these data provide a strong signature for tolerance of therapeutic strategies for fibrosis aimed at CAPN9 antagonism.

Blocking C-Raf alleviated high-dose small-volume radiation-induced epithelial mesenchymal transition in mice lung

The goal of this study was to develop a potential druggable target for lung injury after SABR through the small animal model. Utilising the model, a radiation dose of 70 Gy or 90 Gy was focally (small volume) delivered to the left lung of mice. The highly expressed phosphorylation form of C-Raf was discovered through a protein array experiment, with the protein being extracted from the area of radiated mouse lung tissue, and was confirmed by IHC and western blot. C-Raf activation, along with morphological change and EMT (Epithelial to Mesenchymal Transition) marker expression, was observed after radiation to the mouse type II alveolar cell line MLE-12. C-Raf inhibitor GW5074 was able to reverse the EMT in cells effectively, and was found to be dependent on Twist1 expression. In the animal experiment, pretreatment of GW5074 alleviated EMT and lung injury after 70 Gy radiation was focally delivered to the lung of mice. Conclusively, these results demonstrate that C-Raf inhibitor GW5074 inhibits high-dose small-volume radiation-induced EMT via the C-Raf/Twist1 signalling pathway in mice. Therefore, pharmacological C-Raf inhibitors may be used effectively as inhibitors of SABR-induced lung fibrosis.

FOXM1 nuclear transcription factor translocates into mitochondria and inhibits oxidative phosphorylation

Forkhead box M1 (FOXM1), a nuclear transcription factor that activates cell cycle regulatory genes, is highly expressed in a majority of human cancers. The function of FOXM1 independent of nuclear transcription is unknown. In the present study, we found the FOXM1 protein inside the mitochondria. Using site-directed mutagenesis, we generated FOXM1 mutant proteins that localized to distinct cellular compartments, uncoupling the nuclear and mitochondrial functions of FOXM1. Directing FOXM1 into the mitochondria decreased mitochondrial mass, membrane potential, respiration, and electron transport chain (ETC) activity. In mitochondria, the FOXM1 directly bound to and increased the pentatricopeptide repeat domain 1 (PTCD1) protein, a mitochondrial leucine-specific tRNA binding protein that inhibits leucine-rich ETC complexes. Mitochondrial FOXM1 did not change cellular proliferation. Thus, FOXM1 translocates into mitochondria and inhibits mitochondrial respiration by increasing PTCD1. We identify a new paradigm that FOXM1 regulates mitochondrial homeostasis in a process independent of nuclear transcription.

Circ-MMP2 (circ-0039411) induced by FOXM1 promotes the proliferation and migration of lung adenocarcinoma cells in vitro and in vivo

Numerous reports have stated the significance of cellular events such as proliferation, migration and EMT (epithelial-mesenchymal transition) for cancer development, but the related molecular mechanism remains elusive. FOXM1 (forkhead box transcription M1) is a nuclear co-activator participating in lung adenocarcinoma (LUAD). Thus, this study tried to explain the function of FOXM1 and its downstream molecular mechanism in LUAD. We uncovered FOXM1 upregulation in LUAD and demonstrated that FOXM1 facilitated β-catenin nuclear translocation to activate the transcription of downstream genes. Moreover, we discovered that FOXM1 transcriptionally activated circ0039411 which derived from matrix metallopeptidase 2 (MMP2) (also named as circ-MMP2), while MMP2 is a known downstream target of β-catenin. As for functional investigation, knockdown of circ-0039411 suppressed the proliferation, migration and EMT in LUAD cells and also hindered in vivo growth and metastasis of LUAD tumor. Mechanistically, circ-0039411 enhanced the stability of FOXM1 mRNA by recruiting IGF2BP3 (insulin like growth factor 2 mRNA binding protein 3), thus forming a positive feedback loop. In conclusion, this study revealed that FOXM1-induced circ-MMP2 (circ-0039411) contributes to malignant behaviors of LUAD cells via relying on FOXM1, potentially infusing inspirations for the search of new molecular targets for LUAD treatment.

FoxM1 inhibition ameliorates renal interstitial fibrosis by decreasing extracellular matrix and epithelial-mesenchymal transition

FoxM1 is a transcriptional regulator involved in tumor development, pulmonary fibrosis, and cardiac fibrosis. However, its role in renal interstitial fibrosis (RIF) has yet to be elucidated. We established a TGF-β1-stimulated human proximal tubular epithelial cell (HK-2) model in vitro and a unilateral ureteral obstruction (UUO)-induced rat RIF model in vivo. FoxM1 inhibition was achieved by siRNA interference in vitro and by injecting thiostrepton into UUO-induced RIF rats in vivo. The degree of renal damage and fibrosis were determined by histological assessment via hematoxylin and eosin (H&E) staining. Immunohistochemistry, western blots, and qPCR were used to determine the expression levels of FoxM1, Collagen I, E-cadherin, α-SMA, and Snail1. Our results showed that FoxM1 inhibition could ameliorate RIF and reduce the deposition of Collagen I. H&E staining revealed that renal structural damage, inflammatory cell infiltration, and ECM deposition were significantly attenuated by thiostrepton treatment in the UUO rats. Furthermore, FoxM1 downregulation significantly suppressed epithelial-to-mesenchymal transition, as evidenced by decreased protein and mRNA expression levels of α-SMA and Snail1 and a significant increase in protein and mRNA expression levels of E-cadherin. Collectively, these results suggested that FoxM1 inhibition could be a novel therapeutic strategy for the treatment of RIF.

Regulatory T cells are a double-edged sword in pulmonary fibrosis

Pulmonary fibrosis (PF) is a chronic progressive interstitial lung disease. The pathogenesis of PF has not been clearly elucidated, and there is no obvious effective treatment to arrest the progression of PF to date. A long-term chronic inflammatory response and inappropriate repair process after lung injury are important causes and pathological processes of PF. As an influential type of the body's immune cells, regulatory T cells (Tregs) play an irreplaceable role in inhibiting the inflammatory response and promoting the repair of lung tissue. However, the exact roles of Tregs in the process of PF have not been clearly established, and the available literature concerning the roles of Tregs in PF are contradictory. First, Tregs can advance the progression of pulmonary fibrosis by secreting platelet-derived growth factor (PDGF), transforming growth factor-β (TGF-β) and other related factors, promoting epithelial-mesenchymal transition (EMT) and affecting the Th1 and Th2 balance, etc. Second, Tregs can inhibit PF by promoting the repair of epithelial cell damage, inhibiting the accumulation of fibroblasts, and strongly inhibiting the production and function of other related pro-inflammatory factors and pro-inflammatory cells. Accordingly, in this review, we focus on the multiple roles of Tregs in different models and different pulmonary fibrosis phases, thereby providing theoretical support for a better understanding of the multiple roles of these cells in PF and a theoretical basis for identifying targets for PF therapy.

Loss of FOXM1 in macrophages promotes pulmonary fibrosis by activating p38 MAPK signaling pathway

Idiopathic pulmonary fibrosis (IPF) is a chronic disease with high mortality and is refractory to treatment. Pulmonary macrophages can both promote and repress fibrosis, however molecular mechanisms regulating macrophage functions during fibrosis remain poorly understood. FOXM1 is a transcription factor and is not expressed in quiescent lungs. Herein, we show that FOXM1 is highly expressed in pulmonary macrophages within fibrotic lungs of IPF patients and mouse fibrotic lungs. Macrophage-specific deletion of Foxm1 in mice (myFoxm1-/-) exacerbated pulmonary fibrosis. Inactivation of FOXM1 in vivo and in vitro increased p38 MAPK signaling in macrophages and decreased DUSP1, a negative regulator of p38 MAPK pathway. FOXM1 directly activated Dusp1 promoter. Overexpression of DUSP1 in FOXM1-deficient macrophages prevented activation of p38 MAPK pathway. Adoptive transfer of wild-type monocytes to myFoxm1-/- mice alleviated bleomycin-induced fibrosis. Altogether, contrary to known pro-fibrotic activities in lung epithelium and fibroblasts, FOXM1 has anti-fibrotic function in macrophages by regulating p38 MAPK.

Tartrate-Resistant Acid Phosphatase 5/ACP5 Interacts with p53 to Control the Expression of SMAD3 in Lung Adenocarcinoma

Tartrate-resistant acid phosphatase 5 (TRAP/ACP5) has been shown to involve the development and prognosis of multiple tumors in previous studies; however, the mechanism in lung cancer is still unclear, and thus this study investigated the role of ACP5 in the progression of lung adenocarcinoma. After a series of in vitro and in vivo experiments, we observed that ACP5 expression was increased in lung adenocarcinomas (40/69, 57.97%); importantly, an increased ACP5 level was associated with patient age (p = 0.044) and lymph node metastasis (p = 0.0385). ACP5 overexpression significantly enhanced A549 and NCI-H1975 cell proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) and reduced cell apoptosis. Knocking down the expression of ACP5 could rescue the above cell phenotypes. Furthermore, enhancing ACP5 expression promoted lung adenocarcinoma cell hyperplasia and intrapulmonary metastasis in a mouse model. Additionally, mechanistic studies revealed that ACP5 might regulate p53 phosphorylation at Ser392, thereby enhancing the ubiquitination of p53, which then underwent degradation. Reducing the levels of p53 intensified the transcription of SMAD3, which promotes EMT in lung adenocarcinoma cells. In summary, the present study provides a theoretical basis and important scientific evidence on the key role of ACP5 in lung adenocarcinoma progression by inducing EMT via the regulation of p53/SMAD3 signaling.

Genetic variability of T cell responses in hypersensitivity pneumonitis identified using the BXD genetic reference panel

Hypersensitivity pneumonitis (HP) is an interstitial lung disease that may progress to fibrosis and significant risk of death. HP develops following repeated exposures to inhaled environmental antigens; however, only a fraction of the exposed population develops the disease, suggesting that host genetics contribute to disease susceptibility. We used the BXD family of mice with the Saccharopolyspora rectivirgula (SR) model of HP to investigate the role of genetics in susceptibility to HP. The BXD family is derived from a B6 mother and a D2 father and has been used to map susceptibility loci to numerous diseases. B6, D2, and BXD progeny strains were exposed to SR for 3 wk, and the development of HP was monitored. The B6 and D2 strains developed alveolitis; however, the cellular composition was neutrophilic in the D2 strain and more lymphocytic in the B6 strain. Hematoxylin-eosin staining of lung sections revealed lymphoid aggregates in B6 lungs, whereas D2 lungs exhibited a neutrophilic infiltration. Twenty-eight BXD strains of mice were tested, and the results reveal significant heritable variation for numbers of CD4⁺ or CD8⁺ T cells in the air spaces. There was significant genetic variability for lymphoid aggregates and alveolar wall thickening. We mapped a significant quantitative trait locus (QTL) on chromosome 18 for CD8⁺CD69⁺ T cells that includes cadherin 2 (Cdh2), an excellent candidate gene associated with epithelial-mesenchymal transition, which is upregulated in lungs of strains with HP. These results demonstrate that the BXD family is a valuable and translationally relevant model to identify genes contributing to HP and to devise early and effective interventions.

The implication of LncRNA MALAT1 in promoting chemo-resistance of laryngeal squamous cell carcinoma cells

Background

This study was aimed to evaluate the involvement of lncRNA MALAT1 in modifying chemo‐sensitivity of laryngeal squamous cell carcinoma (LSCC) cell lines.

Methods

Totally 108 pairs of tumor tissues and matched para‐tumor normal tissues were gathered from patients who were pathologically confirmed as LSCC. Meanwhile, LSCC cell lines, including TU686, TU177, AMC‐HN‐8, and LSC‐1, were purchased to evaluate their tolerance to cisplatin, 5‐fluorouracil, paclitaxel, and vincristine. Additionally, CCK‐8 assay, flow cytometry, transwell assay, and wound healing assay were implemented to assess the part of MALAT1 in modulating viability, apoptosis, invasion, and migration of LSCC cell lines.

Results

MALAT1 expression was higher in LSCC tissues than in adjacent normal tissues (P < .05), and LSCC patients who carried highly expressed MALAT1 demonstrated poorer 5‐year survival than ones with low MALAT1 expression (P < .05). For another, expression of MALAT1 was also unusually elevated within TU686, TU177, AMC‐HN‐8, and LSC‐1 cell lines as relative to NHBEC cell line (P < .05). The TU686 cell line therein excelled in resisting the growth‐curbing effects of 5‐fluorouracil (IC50 = 20.44 μmol/L), paclitaxel (IC50 = 35.86 μg/L), and vincristine (IC50 = 0.12 μmol/L), when compared with TU177, AMC‐HN‐8, and LSC‐1 cell line (P < .05). Moreover, there seemed great potential for over‐expressed MALAT1 to enhance the chemo‐resistance of both TU686 and LSC‐1 cell lines (P < .05). Not only that, silencing of MALAT1 tended to undermine the proliferative and metastatic power of TU686 and LSC‐1 cell lines (P < .05).

Conclusion

LncRNA MALAT1 counted in triggering tolerance of LSCC against chemo‐drugs by boosting metastasis and depressing apoptosis of tumor cells.