MicroRNA-29b Mediates Lung Mesenchymal-Epithelial Transition and Prevents Lung Fibrosis in the Silicosis Model

RELA-mediated upregulation of LINC03047 promotes ferroptosis in silica-induced pulmonary fibrosis via SLC39A14

Long non-coding RNAs play a key role in silicosis, a fatal fibrotic lung disease, and there is an urgent need to develop new treatment targets. Long intergenic non-protein-coding RNA 3047 (LINC03047) is associated with cancer, but its role and mechanism in the progression of silicosis require further elucidation. This study investigated the function of LINC03047 in the epithelial-mesenchymal transition (EMT) during silicosis progression. LINC03047 expression was upregulated in SiO2-treated BEAS-2B and A549 cells, promoting SiO2-induced ferroptosis and subsequent EMT. Moreover, knockdown of LINC03047 significantly decreased the expression of solute carrier family 39 member 14 (SLC39A14), a ferrous iron transporter, and inhibition of SLC39A14 alleviated the ferroptosis and EMT caused by LINC03047 overexpression. We further investigated that NF-κB p65 (RELA) was critical for LINC03047 transcription in SiO2-treated BEAS-2B and A549 cells. In vivo experiments showed that SLC39A14 deficiency improved SiO2-induced lipid peroxidation and EMT. Collectively, our study reveals the function of the RELA/LINC03047/SLC39A14 axis in SiO2-induced ferroptosis and EMT, thereby contributing to the identification of novel drug targets for silicosis therapy.

Downregulation of microRNA-29b in cancer and fibrosis: molecular insights and clinical implications

MicroRNA-29b (miR-29b) is known for its therapeutic potential as an antifibrotic and anticancer agent. In fibrotic conditions, miR-29b inhibits fibrogenesis by downregulating crucial regulators such as collagens, extracellular matrix proteins and the transforming growth factor-β pathway. Similarly, in cancer, it acts as a tumor suppressor by downregulating various oncogenes and signaling pathways involved in cancer progression, such as Wnt-β-catenin, p38-mitogen-activated protein kinase and nuclear factor-κB. However, the upregulation of these pathways suppresses miR-29b, contributing to fibrosis and cancer development. Preclinical research and clinical trials have shown that delivering exogenous miR-29b mimics can restore its expression, attenuating tumorigenesis and fibrogenesis. This review discusses miR-29b's potential and its possible therapeutic development for cancer and fibrotic disorders.

Long non-coding RNA H19 mediates the miR-29b/transforming growth factor-β1/Drosophila mothers against decapentaplegic 3 signalling pathway to promote bladder fibrosis in diabetic rats

PURPOSE

Diabetic bladder fibrosis is a common comorbidity. Altered expression of some long non-coding RNAs (LncRNAs) has been associated with bladder fibrosis. LncRNA H19 has been reported to regulate bladder cancer through miR-29b. However, the action mechanism of LncRNA H19 in bladder fibrosis is unclear.

METHODS

In vitro, human bladder smooth muscle cells (HBSMCs) were cultured with transforming growth factor-β1 (TGF-β1) for 48 h to construct cell model of bladder fibrosis. HBSMCs were then transfected with si-LncRNA H19, si-NC, miR-29b-mimic, mimic-NC, or miR-29b-inhibitor. In vivo, Sprague-Dawley (SD) rats were given a high-sucrose-high-fat (HSHF) diet for 4 weeks and injected with streptozotocin (STZ, 50 mg/kg) to induce bladder fibrosis model in diabetic rats, followed by injection of lentiviral particles knocking down LncRNA H19 expression, empty vector, or miR-29b-inhibitor, respectively.

RESULTS

LncRNA H19 was up-regulated in TGF-β1-induced HBSMC fibrosis and STZ-induced diabetic rat bladder fibrosis, whereas miR-29b was down-regulated. si-LncRNA H19 reduced blood glucose levels and improved histopathological damage of bladder tissue in rats. In addition, si-LncRNA H19 or miR-29b-mimic increased the expression of E-cadherin, but decreased the expression of N-cadherin, vimentin, fibronectin (FN) in bladder tissues, and HBSMCs. si-LncRNA H19 reduced TGF-β1/p-drosophila mothers against decapentaplegic 3 (Smad3) protein in HBSMCs and in rat bladder tissues, while miR-29b-inhibitor reversed the effect of si-LncRNA H19.

CONCLUSION

This study indicated that LncRNA H19 may inhibit bladder fibrosis in diabetic rats by targeting miR-29b via the TGF-β1/Smad3 signalling pathway.

Increased m6A-RNA methylation and demethylase FTO suppression is associated with silica-induced pulmonary inflammation and fibrosis

Silicosis is a severe worldwide occupational hazard, characterized with lung tissue inflammation and irreversible fibrosis caused by crystalline silicon dioxide. As the most common and abundant internal modification of messenger RNAs or noncoding RNAs, N6-methyladenosine (m6A) methylation is dysregulated in the chromic period of silicosis. However, whether m6A modification is involved in the early phase of silica-induced pulmonary inflammation and fibrosis and its specific effector cells remains unknown. In this study, we established a pulmonary inflammation and fibrosis mouse model by silica particles on day 7 and day 28. Then, we examined the global m6A modification level by m6A dot blot and m6A RNA methylation quantification kits. The key m6A regulatory factors were analyzed by RTqPCR, Western blot, and immunohistochemistry (IHC) in normal and silicosis mice. The results showed that the global m6A modification level was upregulated in silicosis lung tissues with the demethylase FTO suppression after silica exposure for 7 days and 28 days. METTL3, METTL14, ALKBH5, and other m6A readers had no obvious differences between the control and silicosis groups. Then, single-cell sequencing analysis revealed that thirteen kinds of cells were recognized in silicosis lung tissues, and the mRNA expression of FTO was downregulated in epithelial cells, endothelial cells, fibroblasts, and monocytes. These results were further confirmed in mouse lung epithelial cells (MLE-12) exposed to silica and in the peripheral blood mononuclear cells of silicosis patients. In conclusion, the high level of global m6A modification in the early stage of silicosis is induced by the downregulation of the demethylase FTO, which may provide a novel target for the diagnosis and treatment of silicosis.

microRNA-141-3p mediates epithelial cell proliferation, apoptosis, and epithelial-mesenchymal transition and alleviates pulmonary fibrosis in mice via Spred2

OBJECTIVE

This study probed the mechanism of microRNA (miR)-141-3p in the progression of pulmonary fibrosis (PF).

METHODS

Mice were intratracheally administered with bleomycin (BLM) to establish a PF mouse model. To investigate the effects of miR-141-3p/Spred2 on PF in mice, PF mice received tail vein injections with agomir-141-3p and/or adenovirus vectors overexpressing Spred2 one week after BLM treatment. Then, the pathological changes of lung tissues were analyzed with H&E and Masson's trichrome staining and hydroxyproline contents in lung tissues were measured. For cell experiments, after loss- and gain-of-function assays, the role of miR-141-3p/Spred2 in the apoptosis and viability of TGF-β1-stimulated MLE-12 cells was examined by flow cytometry and CCK-8 assay. miR-141-3p, Spred2, COl 1, and α-SMA expression was determined in cells and mice. Then, the binding of miR-141-3p to Spred2 was tested with a dual-luciferase reporter assay.

RESULTS

There were abnormally upregulated Spred2 and downregulated miR-141-3p in lung tissues of PF mice. TGF-β1 decelerated viability and augmented apoptosis and COl 1 and α-SMA expression in MLE-12 cells. Spred2 knockdown diminished apoptosis and α-SMA and COl 1 expression while enhancing proliferation in TGF-β1-treated MLE-12 cells. Mechanistically, Spred2 was a target gene of miR-141-3p. miR-141-3p upregulation accelerated proliferation and repressed apoptosis and α-SMA and COl 1 expression in TGF-β1-treated MLE-12 cells, which was nullified by further overexpressing Spred2. miR-141-3p alleviated PF in mice by targeting Spred2.

CONCLUSION

miR-141-3p negatively modulates Spred2 to promote proliferation and repress epithelial-mesenchymal transition and apoptosis of epithelial cells, as well as ameliorating PF in mice.

Animal models of silicosis: fishing for new therapeutic targets and treatments

Silicosis as an occupational lung disease has been present in our lives for centuries. Research studies have already developed and implemented many animal models to study the pathogenesis and molecular basis of the disease and enabled the search for treatments. As all experimental animal models used to date have their advantages and disadvantages, there is a continuous search for a better model, which will not only accelerate basic research, but also contribute to clinical aspects and drug development. We review here, for the first time, the main animal models developed to date to study silicosis and the unique advantages of the zebrafish model that make it an optimal complement to other models. Among the main advantages of zebrafish for modelling human diseases are its ease of husbandry, low maintenance cost, external fertilisation and development, its transparency from early life, and its amenability to chemical and genetic screening. We discuss the use of zebrafish as a model of silicosis, its similarities to other animal models and the characteristics of patients at molecular and clinical levels, and show the current state of the art of inflammatory and fibrotic zebrafish models that could be used in silicosis research.

MiR-148a-3p within HucMSC-Derived Extracellular Vesicles Suppresses Hsp90b1 to Prevent Fibroblast Collagen Synthesis and Secretion in Silica-Induced Pulmonary Fibrosis

Silicosis is a fatal occupational respiratory disease caused by the prolonged inhalation of respirable silica. The core event of silicosis is the heightened activity of fibroblasts, which excessively synthesize extracellular matrix (ECM) proteins. Our previous studies have highlighted that human umbilical cord mesenchymal stem cell-derived extracellular vesicles (hucMSC-EVs) hold promise in mitigating silicosis and the significant role played by microRNAs (miRNAs) in this process. Delving deeper into this mechanism, we found that miR-148a-3p was the most abundant miRNA of the differential miRNAs in hucMSC-EVs, with the gene heat shock protein 90 beta family member 1 (Hsp90b1) as a potential target. Notably, miR-148a-3p's expression was downregulated during the progression of silica-induced pulmonary fibrosis both in vitro and in vivo, but was restored after hucMSC-EVs treatment (p < 0.05). Introducing miR-148a-3p mimics effectively hindered the collagen synthesis and secretion of fibroblasts induced by transforming growth factor-β1 (TGF-β1) (p < 0.05). Confirming our hypothesis, Hsp90b1 was indeed targeted by miR-148a-3p, with significantly reduced collagen activity in TGF-β1-treated fibroblasts upon Hsp90b1 inhibition (p < 0.05). Collectively, our findings provide compelling evidence that links miR-148a-3p present in hucMSC-EVs with the amelioration of silicosis, suggesting its therapeutic potential by specifically targeting Hsp90b1, thereby inhibiting fibroblast collagen activities. This study sheds light on the role of miR-148a-3p in hucMSC-EVs, opening avenues for innovative therapeutic interventions targeting molecular pathways in pulmonary fibrosis.

Single-cell transcriptome sequencing-based analysis: probing the mechanisms of glycoprotein NMB regulation of epithelial cells involved in silicosis

Chronic exposure to silica can lead to silicosis, one of the most serious occupational lung diseases worldwide, for which there is a lack of effective therapeutic drugs and tools. Epithelial mesenchymal transition plays an important role in several diseases; however, data on the specific mechanisms in silicosis models are scarce. We elucidated the pathogenesis of pulmonary fibrosis via single-cell transcriptome sequencing and constructed an experimental silicosis mouse model to explore the specific molecular mechanisms affecting epithelial mesenchymal transition at the single-cell level. Notably, as silicosis progressed, glycoprotein non-metastatic melanoma protein B (GPNMB) exerted a sustained amplification effect on alveolar type II epithelial cells, inducing epithelial-to-mesenchymal transition by accelerating cell proliferation and migration and increasing mesenchymal markers, ultimately leading to persistent pulmonary pathological changes. GPNMB participates in the epithelial-mesenchymal transition in distant lung epithelial cells by releasing extracellular vesicles to accelerate silicosis. These vesicles are involved in abnormal changes in the composition of the extracellular matrix and collagen structure. Our results suggest that GPNMB is a potential target for fibrosis prevention.

Dulaglutide Ameliorates Intrauterine Adhesion by Suppressing Inflammation and Epithelial-Mesenchymal Transition via Inhibiting the TGF-β/Smad2 Signaling Pathway

Intrauterine adhesion (IUA) is a common gynecological disease with limited therapeutic options. Dulaglutide is a long-acting glucagon-like peptide-1 (GLP-1) analog with some anti-fibrotic and anti-inflammatory properties; however, its action on IUA remains uncertain. The purpose of the experiments in this study was to explore the effect of dulaglutide on IUA and to elucidate its mechanism to provide new ideas for the clinical treatment of IUA. An IUA mouse model was established via mechanical curettage and inflammation induction; mice received subcutaneous injection with three doses of dulaglutide once a day for two weeks (treatment) or equal amounts of sterile ddH₂O (control), and sham-operated mice were treated similarly to the control mice. Mice were sacrificed, and uterine tissues were subjected to hematoxylin and eosin (H&E) and Masson's trichrome staining for histomorphological and pathological analyses and real-time quantitative polymerase chain reaction (RT-qPCR) and Western blotting (WB) for gene and protein expression analyses. Dulaglutide improved the shape of the uterine cavity, increased endometrial thickness and the number of glands, and significantly reduced the area of collagen fiber deposition in the endometrium. It significantly reduced collagen type I A 1 (COL1A1), interleukin-1beta (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), C-C motif chemokine ligand 2 (CCL2), F4/80 (macrophage), vimentin and transforming growth factor-beta (TGF-β) mRNA levels and COL1A1, IL-1β, IL-6, TNF-α, F4/80, vimentin, E-cadherin, TGF-β, and p-Smad2 protein expression levels. This study demonstrates that dulaglutide reduces inflammatory responses by inhibiting M1 macrophage polarization and inflammatory factor release and may ameliorate fibrosis by inhibiting epithelial-mesenchymal transition (EMT) via TGF-β/Smad2 signaling.

MiR-26a-5p from HucMSC-derived extracellular vesicles inhibits epithelial mesenchymal transition by targeting Adam17 in silica-induced lung fibrosis

Silicosis is one of several potentially fatal occupational pathologies caused by the prolonged inhalation of respirable crystalline silica. Previous studies have shown that lung epithelial-mesenchymal transition (EMT) plays a significant role in the fibrosis effect of silicosis. Human umbilical cord mesenchymal stem cells-derived Extracellular vesicles (hucMSC-EVs) have attracted great interest as a potential therapy of EMT and fibrosis-related diseases. However, the potential effects of hucMSC-EVs in inhibiting EMT in silica-induced fibrosis, as well as its underlying mechanisms, remain largely unknown. In this study, we used the EMT model in MLE-12 cells and observed the effects and mechanism of hucMSC-EVs inhibition of EMT. The results revealed that hucMSC-EVs can indeed inhibit EMT. MiR-26a-5p was highly enriched in hucMSC-EVs but was down-regulated in silicosis mice. We found that miR-26a-5p in hucMSC-EVs was over-expressed after transfecting miR-26a-5p expressing lentivirus vectors into hucMSCs. Subsequently, we explored if miR-26a-5p, attained from hucMSC-EVs, was involved in inhibiting EMT in silica-induced lung fibrosis. Our findings suggested that hucMSC-EVs could deliver miR-26a-5p into MLE-12 cells and cause the inhibition of the Adam17/Notch signalling pathway to ameliorate EMT in silica-induced pulmonary fibrosis. These findings might represent a novel insight into treating silicosis fibrosis.

Differential expression profile of microRNAs in the lung tissues of coal workers with pneumoconiosis and patients with silicosis

The purpose of this study was to characterize the microRNA (miRNA) profile of the lung tissues from coal workers' pneumoconiosis (CWP) and silicosis and to analyze the changes in downstream genes, biological processes, and signaling pathways based on the differently expressed miRNAs. Lung tissues from three CWP patients, eight silicosis patients, and four healthy controls were collected and analyzed for their miRNA profiles using Affymetrix® GeneChip® miRNA Arrays. Differentially expressed miRNAs (DEMs) were identified between the different groups. The miRanda and TargetScan databases were used to predict the putative target genes, and volcano and heat maps were drawn. Gene ontology (GO) and Kyoto encyclopedia of genes and genomes (KEGG) pathway enrichment analyses were then performed to screen the DEMs-associated biological process and signaling pathways, respectively. Further identification with a comprehensive literature research involving particle exposure, fibrosis, inflammation and lung cancer were used to further screen DEMs of CWP and silicosis. Microarray data showed that 375 and 88 miRNAs were differentially expressed in CWP and silicosis lung tissues compared with healthy lung tissues, while 34 miRNAs were differentially expressed in CWP compared with silicosis lung tissues. The GO and KEGG pathway analyses showed that, the target genes were mainly enriched in the TGF-β, MAPK, p53 and other signal pathways. These results provided insight into the miRNA-related underlying mechanisms of CWP and silicosis, and they provided new clues for miRNAs as biomarkers for the diagnosis and differential diagnosis of these two diseases.

Human umbilical cord mesenchymal stem cell-derived extracellular vesicles alleviated silica induced lung inflammation and fibrosis in mice via circPWWP2A/miR-223-3p/NLRP3 axis

Silicosis is a progressive inflammatory disease with poorly defined mechanisms and limited therapeutic options. Recent studies found that microRNAs (miRNAs) and circular RNAs (circRNAs) were involved in the development of respiratory diseases; however, the function of non-coding RNAs in silicosis was still needed to be further explored. We found that miR-223-3p was significantly decreased in macrophages and lung tissues of mice after silica treatment, which were consistent with the results of GEO database microarray analysis. Notably, NLRP3 is a target gene downstream of miR-223-3p. And circular RNA PWWP2A (circPWWP2A) was significantly elevated after silica stimulation. To elucidate the role of these RNAs in silica-induced inflammation in macrophages and lung tissues, we investigated the upstream molecular mechanisms of circPWWP2A on the inflammatory response. The inhibitory effect of miR-223-3p on its target NLRP3 was suppressed by circPWWP2A, which led to lung fibrosis. Our study found that circPWWP2A could adsorb miR-223-3p to regulate NLRP3 after silica stimulation in pulmonary fibrosis. And our results revealed that the circPWWP2A-miR-223-3p-NLRP3 axis was potentially instrumental in managing silica-induced inflammation and fibrosis. Previous studies have demonstrated that human umbilical cord mesenchymal stem cell-derived extracellular vesicles (hucMSC-EVs) exhibit anti-inflammatory and anti-fibrotic effects in multiple organs. However, the potential effectiveness of hucMSC-EVs against silicosis or the underlying mechanisms of their biological outcomes remains unclear. Therefore, we used 3D culture technology to extract hucMSC-EVs and observed their effects in macrophages and lung tissues, respectively. According to the EVmiRNA database, miR-223-3p was abundant in MSC-EVs. In addition, hucMSC-EVs may modulate lung function, reduce the secretion of inflammatory factors (NLRP3, IL-1β, IL-18 and cleaved Caspase-1) and attenuate the deposition of fibrosis-related factors (Collagen Ⅰ, Collagen Ⅲ, fibronectin and α-SMA). In vitro results evinced that hucMSC-EVs reduced the inflammatory response of macrophages and restricted the activation and proliferation of fibroblasts. Moreover, our study showed that hucMSCs-EVs acted as a mediator to transfer miR-223-3p to suppress circPWWP2A, thereby alleviating pulmonary fibrosis through the NLRP3 signaling pathway. These data may provide potentially novel strategies for investigating the pathogenesis of silicosis and developing novel treatments for this disease.

Preclinical Mouse Model of Silicosis

Silicosis is an untreatable occupational lung disease caused by chronic inhalation of crystalline silica. Cyclical release and reuptake of silica particles by macrophages and airway epithelial cells causes repeated tissue damage, characterized by widespread inflammation and progressive diffuse fibrosis. While inhalation is the main route of entry for silica particles in humans, most preclinical studies administer silica via the intratracheal route. In vivo mouse models of lung disease are valuable tools required to bridge the translational gap between in vitro cell culture and human disease. This chapter describes a mouse model of silicosis which mimics clinical features of human silicosis, as well as methods for intranasal instillation of silica and disease analysis. Lung tissue can be collected for histological assessment of silica particle distribution, inflammation, structural damage, and fibrosis in sections stained with hematoxylin and eosin or Masson's trichrome. This approach can be extended to other chronic fibrotic lung diseases where inhalation of small damaging particles such as pollutants causes irreversible disease.

The Immunological Microenvironment and the Emerging Role of Stem Cells Therapy in Peyronie's Disease: A Systematic Narrative Review

Current literature has indicated that Peyronie's disease (PD) could be initiated by microtrauma and the subsequent inflammation episodes that follow. PD could be sorted into acute or chronic status, and it can differ when selecting the clinical therapeutics. PD would cause pain and penile deformity to diseased men and impair their erectile function. Occasionally, surgical revision of the penis might be needed to correct the penile curvature. We find that there are limited effective options of intra-lesion injections for the PD plaques. By searching the databases and screening the literature with the PRISMA 2020 guideline, we observed that several preclinical studies that applied stem cell therapy in treating PD were fruitful in the acute phase. Although in the chronic phase of PD, erectile parameters were not significantly improved, and therefore, future studies might be better elevated in certain aspects, such as the sites selected for harvesting stem cells or changing the centrifugation forces. In this review, we concluded the contemporary understanding of inflammatory microenvironments in PD, the stem cell therapy in PD, and our perspectives on future studies. We concluded that there may be great potential in stem cell therapy for treating both acute and chronic phases PD.

Identification of circRNA expression profiles and the potential role of hsa_circ_0006916 in silicosis and pulmonary fibrosis

Circular RNAs (circRNAs) are emerging as novel regulators in the biological development of various diseases, but their expression profiles, functions and mechanisms in silicosis and pulmonary fibrosis remain largely unexplored. In this study, we constructed a mouse model of pulmonary fibrosis by intratracheal injection of silica particles and then performed transcriptome RNA sequencing of lung tissues. The results showed that 78 circRNAs, 39 miRNAs and 262 mRNAs were differentially expressed. Among them, five circRNAs, three miRNAs and four mRNAs were further selected, and their abnormal expression was verified in mouse fibrotic lung tissues by RT-qPCR assay. The circRNA-associated ceRNA network including 206 ceRNA triplets was constructed based on abnormally expressed circRNAs, miRNAs and mRNAs, and miR-199b-5p, miR-296-5p and miR-708-5p were identified as hub miRNAs connected to circRNAs and mRNAs. Subsequently, GO and KEGG pathway enrichment analyses were performed to detect the potential roles of differentially expressed mRNAs in pulmonary fibrosis, which were mainly involved in immune response, Th17 cell differentiation, NF-κB signaling pathway and PI3K-Akt signaling pathway. Furthermore, we identified that hsa_circ_0006916 was up-regulated in pulmonary fibrosis. To characterize the potential role of hsa_circ_0006916, we transfected siRNA targeting hsa_circ_0006916 into alveolar macrophages and found that knockdown of hsa_circ_0006916 significantly increased the expression levels of M1 molecules IL-1β and TNF-α and reduced the expression level of M2 molecule TGF-β1, indicating that hsa_circ_0006916 may play an important role in the activation of M1-M2 polarization effect in macrophages. Our results provided important evidence on the possible contribution of these abnormal circRNAs to the development of silicosis and pulmonary fibrosis.

The emerging role of epigenetic regulation in the progression of silicosis

Silicosis is one of the most severe occupational diseases worldwide and is characterized by silicon nodules and diffuse pulmonary fibrosis. However, specific treatments for silicosis are still lacking at present. Therefore, elucidating the pathogenesis of silicosis plays a significant guiding role for its treatment and prevention. The occurrence and development of silicosis are accompanied by many regulatory mechanisms, including epigenetic regulation. The main epigenetic regulatory mechanisms of silicosis include DNA methylation, non-coding RNA (ncRNA), and histone modifications. In recent years, the expression and regulation of genes related to silicosis have been explored at epigenetic level to reveal its pathogenesis further, and the identification of aberrant epigenetic markers provides new biomarkers for prediction and diagnosis of silicosis. Here, we summarize the studies on the role of epigenetic changes in the pathogenesis of silicosis to give some clues for finding specific therapeutic targets for silicosis.

The Role of miR-29s in Human Cancers—An Update

MicroRNAs (miRNAs) are small non-coding RNAs that directly bind to the 3’ untranslated region (3’-UTR) of the target mRNAs to inhibit their expression. The miRNA-29s (miR-29s) are suggested to be either tumor suppressors or oncogenic miRNAs that are strongly dysregulated in various types of cancer. Their dysregulation alters the expression of their target genes, thereby exerting influence on different cellular pathways including cell proliferation, apoptosis, migration, and invasion, thereby contributing to carcinogenesis. In the present review, we aimed to provide an overview of the current knowledge on the miR-29s biological network and its functions in cancer, as well as its current and potential applications as a diagnostic and prognostic biomarker and/or a therapeutic target in major types of human cancer.

Exosomal let-7i-5p from three-dimensional cultured human umbilical cord mesenchymal stem cells inhibits fibroblast activation in silicosis through targeting TGFBR1

Silicosis of pulmonary fibrosis (PF) is related to long-term excessive inhalation of silica. The activation of fibroblasts into myofibroblasts is the main terminal effect leading to lung fibrosis, which is of great significance to the study of the occurrence and development of silicosis fibrosis and its prevention and treatment. Exosomes derived from human umbilical cord mesenchymal stem cells (hucMSC-Exos) are considered to be a potential therapy of silica-induced PF, however, their exact mechanism remains unknown. Therefore, this study aims to explore whether hucMSC-Exos affect the activation of fibroblasts to alleviate PF. In this study, a three-dimensional (3D) method was applied to culture hucMSCs and MRC-5 cells (human embryonic lung fibroblasts), and exosomes were isolated from serum-free media, identified by nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM) and Western blotting analysis. Then, the study used an animal model of silica-induced PF to observe the effects of hucMSC-Exos and MRC-5-Exos on activation of fibroblasts. In addition, the activation of fibroblasts was analyzed by Western blotting analysis, wound healing, and migration assay with the treatment of hucMSC-Exos and MRC-5-Exos in NIH-3T3 cells (mouse embryonic fibroblasts). Furthermore, differential expression of microRNAs (DE miRNAs) was measured between hucMSCs-Exos and MRC-5-Exos by high throughput sequence. HucMSC-Exos inhibited the activation of fibroblasts in mice and NIH-3T3 cells. Let-7i-5p was significantly up-regulated in hucMSCs-Exos compared to MRC-5-Exos, which was related to silica-induced PF. Let-7i-5p of hucMSCs-Exos was responsible for the activation of fibroblasts by targeting TGFBR1. Meanwhile, Smad3 was also an important role in the activation of fibroblasts. The study demonstrates that hucMSCs-Exos act as a mediator that transfers let-7i-5p to inhibit the activation of fibroblasts, which alleviates PF through the TGFBR1/Smad3 signaling pathway. The mechanism has potential value for the treatment of silica-induced PF.

Current and prospective applications of exosomal microRNAs in pulmonary fibrosis (Review)

Pulmonary fibrosis (PF) is a chronic, progressive, irreversible and life‑threatening lung disease. However, the pathogenesis and molecular mechanisms of this condition remain unclear. Extracellular vesicles (EVs) are structures derived from the plasma membrane, with a diameter ranging from 30 nm to 5 µm, that play an important role in cell‑to‑cell communications in lung disease, particularly between epithelial cells and the pulmonary microenvironment. In particular, exosomes are a type of EV that can deliver cargo molecules, including endogenous proteins, lipids and nucleic acids, such as microRNAs (miRNAs/miRs). These cargo molecules are encapsulated in lipid bilayers through target cell internalization, receptor‑ligand interactions or lipid membrane fusion. miRNAs are single‑stranded RNA molecules that regulate cell differentiation, proliferation and apoptosis by degrading target mRNAs or inhibiting translation to modulate gene expression. The aim of the present review was to discuss the current knowledge available on exosome biogenesis, composition and isolation methods. The role of miRNAs in the pathogenesis of PF was also reviewed. In addition, emerging diagnostic and therapeutic properties of exosomes and exosomal miRNAs in PF were described, in order to highlight the potential applications of exosomal miRNAs in PF.

Epigenetic Changes and Functions in Pneumoconiosis

Pneumoconiosis is one of the most common occupational diseases in the world, and specific treatment methods of pneumoconiosis are lacking at present, so it carries great social and economic burdens. Pneumoconiosis, coronavirus disease 2019, and idiopathic pulmonary fibrosis all have similar typical pathological changes-pulmonary fibrosis. Pulmonary fibrosis is a chronic lung disease characterized by excessive deposition of the extracellular matrix and remodeling of the lung tissue structure. Clarifying the pathogenesis of pneumoconiosis plays an important guiding role in its treatment. The occurrence and development of pneumoconiosis are accompanied by epigenetic factors (e.g., DNA methylation and noncoding RNA) changes, which in turn can promote or inhibit the process of pneumoconiosis. Here, we summarize epigenetic changes and functions in the several kinds of evidence classification (epidemiological investigation, in vivo, and in vitro experiments) and main types of cells (macrophages, fibroblasts, and alveolar epithelial cells) to provide some clues for finding specific therapeutic targets for pneumoconiosis and even for pulmonary fibrosis.

Research Progress of Epithelial-mesenchymal Transition Treatment and Drug Resistance in Colorectal Cancer

Colorectal cancer (CRC) is one of the most common malignancies in the world that seriously affects human health. Activation of epithelial-mesenchymal transition (EMT) is a physiological phenomenon during embryonic development that is essential for cell metastasis. EMT participates in various biological processes associated with trauma repair, organ fibrosis, migration, metastasis, and infiltration of tumor cells. EMT is a new therapeutic target for CRC; however, some patients with CRC develop resistance to some drugs due to EMT. This review focuses specifically on the status of treatments that target the EMT process and its role in the therapeutic resistance observed in patients with CRC.

miR-29b Regulates TGF-β1-Induced Epithelial-Mesenchymal Transition by Inhibiting Heat Shock Protein 47 Expression in Airway Epithelial Cells

Tissue remodeling contributes to ongoing inflammation and refractoriness of chronic rhinosinusitis (CRS). During this process, epithelial-mesenchymal transition (EMT) plays an important role in dysregulated remodeling and both microRNA (miR)-29b and heat shock protein 47 (HSP47) may be engaged in the pathophysiology of CRS. This study aimed to determine the role of miR-29b and HSP47 in modulating transforming growth factor (TGF)-β1-induced EMT and migration in airway epithelial cells. Expression levels of miR-29b, HSP47, E-cadherin, α-smooth muscle actin (α-SMA), vimentin and fibronectin were assessed through real-time PCR, Western blotting, and immunofluorescence staining. Small interfering RNA (siRNA) targeted against miR-29b and HSP47 were transfected to regulate the expression of EMT-related markers. Cell migration was evaluated with wound scratch and transwell migration assay. miR-29b mimic significantly inhibited the expression of HSP47 and TGF-β1-induced EMT-related markers in A549 cells. However, the miR-29b inhibitor more greatly induced the expression of them. HSP47 knockout suppressed TGF-β1-induced EMT marker levels. Functional studies indicated that TGF-β1-induced EMT was regulated by miR-29b and HSP47 in A549 cells. These findings were further verified in primary nasal epithelial cells. miR-29b modulated TGF-β1-induced EMT-related markers and migration via HSP47 expression modulation in A549 and primary nasal epithelial cells. These results suggested the importance of miR-29b and HSP47 in pathologic tissue remodeling progression in CRS.

Metformin Attenuates Silica-Induced Pulmonary Fibrosis by Activating Autophagy via the AMPK-mTOR Signaling Pathway

Long-term exposure to crystalline silica particles leads to silicosis characterized by persistent inflammation and progressive fibrosis in the lung. So far, there is no specific treatment to cure the disease other than supportive care. In this study, we examined the effects of metformin, a prescribed drug for type || diabetes on silicosis and explored the possible mechanisms in an established rat silicosis model in vivo, and an in vitro co-cultured model containing human macrophages cells (THP-1) and human bronchial epithelial cells (HBEC). Our results showed that metformin significantly alleviated the inflammation and fibrosis of lung tissues of rats exposed to silica particles. Metformin significantly reduced silica particle-induced inflammatory cytokines including transforming growth factor-β1 (TGF-β1), tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) in rat lung tissue and HBEC culture supernatant. The protein levels of Vimentin and α-smooth muscle actin (α-SMA) were significantly decreased by metfomin while expression level of E-cadherin (E-Cad) increased. Besides, metformin increased the expression levels of phosphorylated adenosine 5′-monophosphate (AMP)-activated protein kinase (p-AMPK), microtubule-associated protein (MAP) light chain 3B (LC3B) and Beclin1 proteins, and reduced levels of phosphorylated mammalian target of rapamycin (p-mTOR) and p62 proteins in vivo and in vitro. These results suggest that metformin could inhibit silica-induced pulmonary fibrosis by activating autophagy through the AMPK-mTOR pathway.

Analyzing the Effect of Vitronectin on Cell Growth and Mesenchymal-Epithelial Transition of Pulmonary Fibroblast Cells

PURPOSE

Vitronectin (VTN), a multifunctional glycoprotein, is involved in various biological and pathological processes. The purpose of this study was to explore the effect of VTN on mesenchymal-epithelial transition (MET) of pulmonary fibroblast cells.

METHODS

Lentivirus encoding for VTN-specific shRNA was constructed and infected into the cultured fibroblast WI-38 cells. Real-time PCR and Western blot were applied to examine the expression of VTN in WI-38 cells. MTT assay was used to assess cell proliferation. Western blot was conducted to examine the expression of MET-related and apoptosis-related proteins.

RESULTS

The knockdown of VTN significantly inhibited the growth of WI-38 cells compared to the control group. Meanwhile, knockdown of VTN remarkably increased the expression of Bax and Caspase 3 compared with the control group. Furthermore, knockdown of VTN significantly promoted the expression of E-cadherin in comparison to control group.

CONCLUSIONS

Knockdown of VTN promoted the expression of apoptosis-related factors, meanwhile, facilitated the MET process of fibroblast cells by regulating the expression of relevant factors. In sum, VTN performed a potential regulator in cell growth and MET of pulmonary fibroblast cells, which can be considered as a potential target for diagnose and therapy of relevant diseases.

circPTPN12/miR-21-5 p/∆Np63α pathway contributes to human endometrial fibrosis

Emerging evidence demonstrates the important role of circular RNAs (circRNAs) in regulating pathological processes in various diseases including organ fibrosis. Endometrium fibrosis is the leading cause of uterine infertility, but the role of circRNAs in its pathogenesis is largely unknown. Here, we provide the evidence that upregulation of circPTPN12 in endometrial epithelial cells (EECs) of fibrotic endometrium functions as endogenous sponge of miR-21-5 p to inhibit miR-21-5 p expression and activity, which in turn results in upregulation of ΔNp63α to induce the epithelial mesenchymal transition (EMT) of EECs (EEC-EMT). In a mouse model of endometrium fibrosis, circPTPN12 appears to be a cofactor of driving EEC-EMT and administration of miR-21-5 p could reverse this process and improve endometrial fibrosis. Our findings revealed that the dysfunction of circPTPN12/miR-21-5 p/∆Np63α pathway contributed to the pathogenesis of endometrial fibrosis.

The Roles of MicroRNAs and Extracellular Vesicles in the Pathogeneses of Idiopathic Pulmonary Fibrosis and Acute Respiratory Distress Syndrome

The lungs are the organs that work for gas exchange. The basic structure of the lungs is an alveolus, which consists of various types of parenchymal cells and bone marrow-derived cells. Therefore, because the lungs consist of various types of cells with various functions, communication among the different types of the cells should play important roles for the homeostasis and response to disease pathogens. In the past decades, researchers have focused on cytokines or adhesion molecules to reveal the intercellular communication for understanding the homeostasis and pathogenesis in the lungs. Recent investigations have revealed that an extracellular vesicle can move among cells for transferring substances including microRNAs in the vesicles as an intercellular messenger. MicroRNAs and extracellular vesicles are therefore attracting increasing attention from both translational and clinical researchers because these emerging intercellular communication tools seem to be useful for further understanding of the disease pathogenesis as well as the biomarkers for diagnosis and prognosis of the diseases including cancer and inflammatory diseases. This review article is an attempt to review studies about microRNAs and extracellular vesicles in terms of their roles in normal conditions and refractory diseases of the lungs such as idiopathic pulmonary fibrosis and acute respiratory distress syndrome including our recent study about pulmonary microvascular endothelial microparticles particles as the biomarker for diagnosis and prognosis of acute respiratory distress syndrome. This review also addresses the possibility of microRNAs and extracellular vesicles as new clinical tools for the diagnosis or treatment for these refractory respiratory diseases.

New Insights into Pathomechanisms and Treatment Possibilities for Lung Silicosis

Inhalation of silica particles is an environmental and occupational cause of silicosis, a type of pneumoconiosis. Development of the lung silicosis is a unique process in which the vicious cycle of ingestion of inhaled silica particles by alveolar macrophages and their release triggers inflammation, generation of nodular lesions, and irreversible fibrosis. The pathophysiology of silicosis is complex, and interactions between the pathomechanisms have not been completely understood. However, elucidation of silica-induced inflammation cascades and inflammation-fibrosis relations has uncovered several novel possibilities of therapeutic targeting. This article reviews new information on the pathophysiology of silicosis and points out several promising treatment approaches targeting silicosis-related pathways.

The Impact of Non-coding RNAs in the Epithelial to Mesenchymal Transition

Epithelial to mesenchymal transition (EMT) is a course of action that enables a polarized epithelial cell to undertake numerous biochemical alterations that allow it to adopt features of mesenchymal cells such as high migratory ability, invasive properties, resistance to apoptosis, and importantly higher-order formation of extracellular matrix elements. EMT has important roles in implantation and gastrulation of the embryo, inflammatory reactions and fibrosis, and transformation of cancer cells, their invasiveness and metastatic ability. Regarding the importance of EMT in the invasive progression of cancer, this process has been well studies in in this context. Non-coding RNAs (ncRNAs) have been shown to exert critical function in the regulation of cellular processes that are involved in the EMT. These processes include regulation of some transcription factors namely SNAI1 and SNAI2, ZEB1 and ZEB2, Twist, and E12/E47, modulation of chromatin configuration, alternative splicing, and protein stability and subcellular location of proteins. In the present paper, we describe the influence of ncRNAs including microRNAs and long non-coding RNAs in the EMT process and their application as biomarkers for this process and cancer progression and their potential as therapeutic targets.

Snail-mediated partial epithelial mesenchymal transition augments the differentiation of local lung myofibroblast

The pathogenesis of pulmonary fibrosis diseases is considered to be related with environmental exposures, but the exact mechanism is unclear and there are no effective treatments. The contribution of epithelial-mesenchymal transition (EMT) to lung fibrosis has been controversial. It was found that partial EMT might play a vital role in renal fibrosis. We also found that partial EMT might be involved in fibrosis diseases. In this study, we used a silicosis animal model of pulmonary fibrosis to observe whether partial EMT existed in pulmonary fibrosis disease and a co-culture system culturing fibroblasts and alveolar epithelial cells stimulated by TGF-β1 to evaluate the probable effects of partial EMT, thus determined the probable role of partial EMT in pulmonary fibrosis diseases. In vivo, the results revealed that partial EMT might exist in silica-induced lung fibrosis model and Snail which is a potent EMT inducer was involved during the process. In vitro, a co-culture system was used to evaluate the effects of EMT in murine alveolar epithelial type II (ATII) cells on the activation of underlying murine lung fibroblasts into myofibroblasts. The results showed that epithelial cells undergoing EMT promoted the differentiation of lung myofibroblast and this epithelial-mesenchymal crosstalk was mainly controlled by Snail. Following Snail silencing the EMT and the activation of NIH-3T3 into myofibroblast were obviously inhibited. It indicated that targeting this novel Snail might be a viable strategy for the treatment of lung fibrosis diseases.

Investigation of MicroRNA and transcription factor mediated regulatory network for silicosis using systems biology approach

Silicosis is a major health issue among workers exposed to crystalline silica. Genetic susceptibility has been implicated in silicosis. The present research demonstrates key regulatory targets and propagated network of gene/miRNA/transcription factor (TF) with interactions responsible for silicosis by integrating publicly available microarray data using a systems biology approach. Array quality is assessed with the Quality Metrics package of Bioconductor, limma package, and the network is constructed using Cytoscape. We observed and enlist 235 differentially expressed genes (DEGs) having up-regulation expression (85 nos) and down-regulation expression (150 nos.) in silicosis; and 24 TFs for the regulation of these DEGs entangled with thousands of miRNAs. Functional enrichment analysis of the DEGs enlighten that, the maximum number of DEGs are responsible for biological process viz, Rab proteins signal transduction (11 nos.) and Cellular Senescence (20 nos.), whereas IL-17 signaling pathway (16 nos.) and Signalling by Nuclear Receptors (14 nos.) etc. are Biological Pathway involving more DEGs. From the identified 1100 high target microRNA (miRNA)s involved in silicosis, 1055 miRNAs are found to relate with down-regulated genes and 847 miRNAs with up-regulated genes. The CDK19 gene (Up-regulated) is associated with 617 miRNAs whereas down-regulated gene ARID5B is regulated by as high as 747 high target miRNAs. In Prediction of Small-molecule signatures, maximum scoring small-molecule combinations for the DEGs have shown that CGP-60774 (with 20 combinations), alvocidib (with 15 combinations) and with AZD-7762 (24 combinations) with few other drugs having the high probability of success.

The Epithelial-to-Mesenchymal Transition as a Possible Therapeutic Target in Fibrotic Disorders

Fibrosis is a chronic and progressive disorder characterized by excessive deposition of extracellular matrix, which leads to scarring and loss of function of the affected organ or tissue. Indeed, the fibrotic process affects a variety of organs and tissues, with specific molecular background. However, two common hallmarks are shared: the crucial role of the transforming growth factor-beta (TGF-β) and the involvement of the inflammation process, that is essential for initiating the fibrotic degeneration. TGF-β in particular but also other cytokines regulate the most common molecular mechanism at the basis of fibrosis, the Epithelial-to-Mesenchymal Transition (EMT). EMT has been extensively studied, but not yet fully explored as a possible therapeutic target for fibrosis. A deeper understanding of the crosstalk between fibrosis and EMT may represent an opportunity for the development of a broadly effective anti-fibrotic therapy. Here we report the evidences of the relationship between EMT and multi-organ fibrosis, and the possible therapeutic approaches that may be developed by exploiting this relationship.

Mitochondrial microRNAs: A Putative Role in Tissue Regeneration

The most famous role of mitochondria is to generate ATP through oxidative phosphorylation, a metabolic pathway that involves a chain of four protein complexes (the electron transport chain, ETC) that generates a proton-motive force that in turn drives the ATP synthesis by the Complex V (ATP synthase). An impressive number of more than 1000 mitochondrial proteins have been discovered. Since mitochondrial proteins have a dual genetic origin, it is predicted that ~99% of these proteins are nuclear-encoded and are synthesized in the cytoplasmatic compartment, being further imported through mitochondrial membrane transporters. The lasting 1% of mitochondrial proteins are encoded by the mitochondrial genome and synthesized by the mitochondrial ribosome (mitoribosome). As a result, an appropriate regulation of mitochondrial protein synthesis is absolutely required to achieve and maintain normal mitochondrial function. Regarding miRNAs in mitochondria, it is well-recognized nowadays that several cellular mechanisms involving mitochondria are regulated by many genetic players that originate from either nuclear- or mitochondrial-encoded small noncoding RNAs (sncRNAs). Growing evidence collected from whole genome and transcriptome sequencing highlight the role of distinct members of this class, from short interfering RNAs (siRNAs) to miRNAs and long noncoding RNAs (lncRNAs). Some of the mechanisms that have been shown to be modulated are the expression of mitochondrial proteins itself, as well as the more complex coordination of mitochondrial structure and dynamics with its function. We devote particular attention to the role of mitochondrial miRNAs and to their role in the modulation of several molecular processes that could ultimately contribute to tissue regeneration accomplishment.

Exosomes derived from three-dimensional cultured human umbilical cord mesenchymal stem cells ameliorate pulmonary fibrosis in a mouse silicosis model

Background

Silicosis is an occupational respiratory disease caused by long-term excessive silica inhalation, which is most commonly encountered in industrial settings. Unfortunately, there is no effective therapy to delay and cure the progress of silicosis. In the recent years, stem cell therapy has emerged as an attractive tool against pulmonary fibrosis (PF) owing to its unique biological characteristics. However, the direct use of stem cells remains limitation by many risk factors for therapeutic purposes. The exclusive utility of exosomes secreted from stem cells, rather than cells, has been considered a promising alternative to overcome the limitations of cell-based therapy while maintaining its advantages.

Methods and results

In this study, we first employed a three-dimensional (3D) dynamic system to culture human umbilical cord mesenchymal stem cell (hucMSC) spheroids in a microcarrier suspension to yield exosomes from serum-free media. Experimental silicosis was induced in C57BL/6J mice by intratracheal instillation of a silica suspension, with/without exosomes derived from hucMSC (hucMSC-Exos), injection via the tail vein afterwards. The results showed that the gene expression of collagen I (COL1A1) and fibronectin (FN) was upregulated in the silica group as compared to that in the control group; however, this change decreased with hucMSC-Exo treatment. The value of FEV0.1 decreased in the silica group as compared to that in the control group, and this change diminished with hucMSC-Exo treatment. These findings suggested that hucMSC-Exos could inhibit silica-induced PF and regulate pulmonary function. We also performed in vitro experiments to confirm these findings; the results revealed that hucMSC-Exos decreased collagen deposition in NIH-3T3 cells exposed to silica.

Conclusions

Taken together, these studies support a potential role for hucMSC-Exos in ameliorating pulmonary fibrosis and provide new evidence for improving clinical treatment induced by silica.

Supplementary information

The online version contains supplementary material available at 10.1186/s13287-020-02023-9.

Diagnostic and Therapeutic Implications of microRNAs in Non-Small Cell Lung Cancer

microRNAs (miRNAs), endogenous suppressors of target mRNAs, are deeply involved in every step of non-small cell lung cancer (NSCLC) development, from tumor initiation to progression and metastasis. They play roles in cell proliferation, apoptosis, angiogenesis, epithelial-to-mesenchymal transition, migration, invasion, and metastatic colonization, as well as immunosuppression. Due to their versatility, numerous attempts have been made to use miRNAs for clinical applications. miRNAs can be used as cancer subtype classifiers, diagnostic markers, drug-response predictors, prognostic markers, and therapeutic targets in NSCLC. Many challenges remain ahead of their actual clinical application; however, when achieved, the use of miRNAs in the clinic is expected to enable great progress in the diagnosis and treatment of patients with NSCLC.

Sodium tanshinone IIA sulfonate attenuates silica-induced pulmonary fibrosis in rats via activation of the Nrf2 and thioredoxin system

Silicosis is characterized by pulmonary fibrosis due to long-term inhalation of silica particles. Although the cause of this serious disease is known, its pathogenesis remains unclear and there are currently no specific treatments. Recent studies have shown that the anti-oxidant transcription factor Nrf2 is expressed at reduced levels in fibrotic foci, which may be related to disease progression. However, the molecular mechanisms by which this might occur have yet to be elucidated. Sodium tanshinone IIA sulfonate (STS), an extract of Salvia miltiorrhiza, is used in traditional Chinese medicine in the treatment of coronary heart disease. STS has been shown to play a strong anti-oxidative role in various organs. Here, we employed a rat model to explore the effects of STS on oxidative stress and the progression of fibrosis in silicosis. STS significantly reduced collagen deposition in the lungs, thereby antagonising silicosis. Immunohistochemical and immunofluorescence staining showed that Nrf2 was differentially expressed in lung cells during silica induced fibrosis, and chromatin immunoprecipitation-sequencing experiments demonstrated that Nrf2 promoted the expression of the antioxidant proteins thioredoxin and thioredoxin reductase. Our results suggest that the anti-fibrotic effects of STS may be related to upregulation of Nrf2 nuclear expression, especially in fibrotic lesions, and the promotion of thioredoxin and thioredoxin reductase expression. Our findings may open up new avenues for the development of STS as a treatment for silicosis.

A novel pathophysiological classification of silicosis models provides some new insights into the progression of the disease

Silicosis is caused by massive inhalation of silica-based particles, which leads to pulmonary inflammation, pulmonary fibrosis and lung dysfunction. Currently, the pathophysiological process of silicosis has not been well studied. Here, we defined the progression of silicosis as four stages by unsupervised clustering analysis: normal stage, inflammatory stage, progressive stage and fibrotic stage. Specifically, in normal stage, the lung function was normal, and no inflammation or fibrosis was detected in the lung tissue. Inflammatory stage showed a remarkable pulmonary inflammation but mild fibrosis and lung dysfunction. In progressive stage, significant lung dysfunction was observed, while pulmonary inflammation and fibrosis continued to deteriorate. Fibrotic stage revealed the most severe pulmonary fibrosis and lung dysfunction but no significant deterioration in inflammation. Since the common features were founded in both silicosis patients and rodents, we speculated that the pathophysiological processes of silicosis in patients might be similar to the rodents. Collectively, our new classification identified the process of silicosis, clarified the pathophysiological features of each stage, and provided some new insights for the progression of the disease.

miR-34a-5p Attenuates EMT through targeting SMAD4 in silica-induced pulmonary fibrosis

Silicosis is an incurable occupational disease, and its pathological feature is diffuse pulmonary fibrosis. Pulmonary epithelial-mesenchymal transition (EMT) is one of the important events in the pathogenesis of silicosis. Previous studies found that abnormal expression of various microRNAs (miRNAs) involved in the development of lung fibrosis. However, their roles in silicosis have not been elucidated. To research the biological effects of miR-34a in EMT process in silica-induced lung fibrosis, we established the silicosis model in mouse and miR-34a intervention in a cell model of TGF-β1 stimulated lung epithelial cells (A549). The results showed that miR-34a expression was down-regulated in the fibrotic lung tissue after silica treatment, and it was similarly expressed in A549 cells stimulated by TGF-β1. Meanwhile, silica-induced EMT process can increase expression of two mesenchymal markers, α-SMA and vimentin. Furthermore, overexpression miR-34a markedly inhibited EMT stimulated by TGF-β1. Mechanistically, SMAD4 was identified as the target of miR-34a. SMAD4 levels decreased in mRNA and protein levels in A549 cells upon miR-34a overexpression. In addition, the knockdown of SMAD4 blocked the EMT process. Taken together, miR-34a regulated EMT, which might be partially realized by targeting SMAD4. Our data might provide new insight into treatment targets for silica-induced pulmonary fibrosis.

miR-29b-3p protects cardiomyocytes against endotoxin-induced apoptosis and inflammatory response through targeting FOXO3A

Cardiac dysfunction represents a main component of death induced by sepsis in critical care units. And microRNAs (miRNAs) have been reported as important modulators or biomarkers of sepsis. However, the molecular detail of miRNAs involved in septic cardiac dysfunction remains unclear. Here we showed that endotoxin (lipopolysaccharide, LPS) significantly down-regulated expression of miR-29b-3p in heart. Increased expression of miR-29b-3p by lentivirus improved cardiac function and attenuated damage of cardiac induced by LPS in mice. Furthermore, overexpression or knockdown of miR-29b-3p showed its crucial roles on regulation of apoptosis and production of pro-inflammatory cytokines in NRCMs through directly targeting FOXO3A. miR-29b-3p ameliorates inflammatory damage likely via reducing activation of MAPKs and nuclear-translocation of NF-κB to block LPS-activated NF-κB signaling. Notably, miR-29b is also down-regulated in septic patients' plasma compared with normal subjects, indicating a potential clinical relevance of miR-29b. Taken together, our findings demonstrate that upregulation of miR-29b-3p can attenuate myocardial injury induced by sepsis via regulating FOXO3A, which provide a potential therapy target for interference of septic cardiac dysfunction.

Pulmonary Silicosis Alters MicroRNA Expression in Rat Lung and miR-411-3p Exerts Anti-fibrotic Effects by Inhibiting MRTF-A/SRF Signaling

To identify potential therapeutic targets for pulmonary fibrosis induced by silica, we studied the effects of this disease on the expression of microRNAs (miRNAs) in the lung. Rattus norvegicus pulmonary silicosis models were used in conjunction with high-throughput screening of lung specimens to compare the expression of miRNAs in control and pulmonary silicosis tissues. A total of 70 miRNAs were found to be differentially expressed between control and pulmonary silicosis tissues. This included 41 miRNAs that were upregulated and 29 that were downregulated relative to controls. Among them, miR-292-5p, miR-155-3p, miR-1193-3p, miR-411-3p, miR-370-3p, and miR-409a-5p were found to be similarly altered in rat lung and transforming growth factor (TGF)-β1-induced cultured fibroblasts. Using miRNA mimics and inhibitors, we found that miR-1193-3p, miR-411-3p, and miR-370-3p exhibited potent anti-fibrotic effects, while miR-292-5p demonstrated pro-fibrotic effects in TGF-β1-stimulated lung fibroblasts. Moreover, we also found that miR-411-3p effectively reduced pulmonary silicosis in the mouse lung by regulating Mrtfa expression, as demonstrated using biochemical and histological assays. In conclusion, our findings indicate that miRNA expression is perturbed in pulmonary silicosis and suggest that therapeutic interventions targeting specific miRNAs might be effective in the treatment of this occupational disease.

MiR-411-3p alleviates Silica-induced pulmonary fibrosis by regulating Smurf2/TGF-β signaling

Occupational exposure to silica dust particles was the major cause of pulmonary fibrosis, and many miRNAs have been demonstrated to regulate target mRNAs in silicosis. In the present study, we found that a decreasing level of miR-411-3p in silicosis rats and lung fibroblasts induced by TGF-β1. Enlargement of miR-411-3p could inhibit the cell proliferation and migration in lung fibroblasts with TGF-β1 treatment and attenuate lung fibrosis in silicotic mice. In addition, a mechanistic study showed that miR-411-3p exert its inhibitory effect on Smad ubiquitination regulatory factor 2 (Smurf2) expression and decrease ubiquitination degradation of Smad7 regulated by smurf2, result in blocking of TGF-β/Smad signaling. We proposed that increased expression of miR-411-3p abrogates silicosis by blocking activation of TGF-β/Smad signaling through decreasing ubiquitination degradation effect of smurf2 on Smad7.

Exosomes derived from mesenchymal stem cells reverse EMT via TGF-β1/Smad pathway and promote repair of damaged endometrium

Background

Intrauterine adhesion (IUA) is one of the most serious complications in patients with endometrial repair disorder after injury. Currently, there is no effective treatment for IUA. Stem cell is the main candidate of new therapy, which functions mainly through paracrine mechanism. Stem-derived exosomes (Exo) play an important role in tissue injury. Here, we mainly aim to study the effect of bone marrow mesenchymal stem cell (BMSC)-derived Exo on repairing endometrium of IUA animal models and its effect on TGF-β1 induced EMT in endometrial epithelial cells (EECs).

Methods

Totally, 64 female rabbits were randomly divided into Sham operation group, model group, BMSC treatment group, and Exo treatment group. EMT in EECs was induced by TGF-β1. Then, EECs were treated with Exo (25 μg/ml, 50 μg/ml, 100 μg/ml) for 24 h. HE staining and Masson staining were used to evaluate the changes in glandular number and fibrosis area. The expression levels of CK19 and VIM were detected by immunohistochemistry. Western blotting was used to detect the expression of CK19, VIM, FSP-1, E-cadherin, TGF-β1, TGF-β1R, Smad 2, and P-Smad 2. RT-PCR was used to detect mRNA expression levels of CK19, VIM, FSP-1, E-cadherin, TGF-β1, TGF-β1R, and Smad 2.

Results

Compared with the model group, the number of endometrial glands was significantly increased and endometrial fibrosis area was significantly decreased in BMSC and Exo groups (P < 0.05). CK19 level significantly increased whereas VIM level significantly decreased after treatment of BMSCs and Exo (P < 0.05). Additionally, the expressions of TGF-β1, TGF-β1R, and Smad2 mRNA were all significantly decreased after BMSC and Exo treatment (P < 0.05). Besides, phosphorylation levels of TGF-β1, TGF-β1R, and Smad2 were also significantly decreased in BMSC and Exo treatment groups (P < 0.05). Furthermore, there was no significant difference between BMSC and Exo treatment groups (P > 0.05). EMT was induced in EECs by 60 ng/ml TGF-β1 for 24 h. After Exo treatment for 24 h, mRNA expressions of CK-19 and E-cadherin increased, while those of VIM, FSP-1, TGF-β1, and Smad2 decreased. Additionally, protein expressions of CK-19 and E-cadherin increased, while those of VIM, FSP-1, TGF-β1, Smad2, and P-Smad2 decreased.

Conclusions

BMSC-derived Exo is involved in the repair of injured endometrium, with similar effect to that of BMSC, and can reverse EMT in rabbit EECs induced by TGF-β1. BMSC-derived Exo may promote endometrial repair by the TGF-β1/Smad signaling pathway.

MicroRNA-26b-5p Inhibits Mouse Liver Fibrogenesis and Angiogenesis by Targeting PDGF Receptor-Beta

Here microRNAs (miRNAs) with potentially therapeutic effects were screened and explored during liver fibrogenesis and angiogenesis via targeting the important mediators. Chimera mice with EGFP⁺ bone marrow mesenchymal stromal cells (BMSCs) were fed with methionine-choline-deficient and high-fat (MCDHF) diet to induce liver injury. Increased expression of platelet-derived growth factor receptor-beta (PDGFR-β) was detected in MCDHF mice, with a positive correlation to fibrosis and angiogenesis markers. BMSCs contributed to the significant proportion of PDGFR-β⁺ cells in the fibrotic liver. MicroRNA-26b-5p (miR-26b-5p) was predicted to target PDGFR-β from three databases. The hepatic expression of miR-26b-5p was decreased in the fibrotic liver, with a negative correlation to PDGFR-β and fibrosis and angiogenesis markers. miR-26b-5p directly targeted PDGFR-β in TGF-β1-treated BMSCs by pull-down and lucifer reporter assays, which can be sponged by long non-coding RNA (lncRNA) maternally expressed gene 3 (lncMEG3). Microarray analysis revealed that miR-26b-5p overexpression affected a list of genes associated with fibrosis and angiogenesis. In vivo miR-26b-5p negatively regulated PDGFR-β expression and attenuated liver fibrosis and angiogenesis. Together, miR-26b-5p inhibits liver fibrogenesis and angiogenesis via directly targeting PDGFR-β and interacting with lncMEG3, which may represent an effective therapeutic strategy for liver fibrosis.