MicroRNA-101 attenuates pulmonary fibrosis by inhibiting fibroblast proliferation and activation

Circulating MicroRNAs in Idiopathic Pulmonary Fibrosis: A Narrative Review

Idiopathic pulmonary fibrosis (IPF) is a chronic, deathly disease with no recognized effective cure as yet. Furthermore, its diagnosis and differentiation from other diffuse interstitial diseases remain a challenge. Circulating miRNAs have been measured in IPF and have proven to be an adequate option as biomarkers for this disease. These miRNAs, released into the circulation outside the cell through exosomes and proteins, play a crucial role in the pathogenic pathways and mechanisms involved in IPF development. This review focuses on the serum/plasma miRNAs reported in IPF that have been validated by real-time PCR and the published evidence regarding the fibrotic process. First, we describe the mechanisms by which miRNAs travel through the circulation (contained in exosomes and bound to proteins), as well as the mechanism by which miRNAs perform their function within the cell. Subsequently, we summarize the evidence concerning miRNAs reported in serum/plasma, where we find contradictory functions in some miRNAs (dual functions in IPF) when comparing the findings in vitro vs. in vivo. The most relevant finding, for instance, the levels of miRNAs let-7d and miR-21 reported in the serum/plasma in IPF, correspond to those found in studies in lung fibroblasts and the murine bleomycin model, reinforcing the usefulness of these miRNAs as future biomarkers in IPF.

Noncoding RNA network crosstalk in organ fibrosis

Fibrosis is a process involving excessive accumulation of extracellular matrix components, the severity of which interferes with the function of the organ in question. With the advances in RNA sequencing and in-depth molecular studies, a large number of current studies have pointed out the irreplaceable role of non-coding RNAs (ncRNAs) in the pathophysiological development of organ fibrosis. Here, by summarizing the results of a large number of studies on the interactions between ncRNAs, some studies have found that long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs), among others, are able to act as sponges or decoy decoys for microRNAs (miRNAs), act as competing endogenous RNAs (ceRNAs) to regulate the expression of miRNAs, and subsequently act on different mRNA targets, playing a role in the development of fibrosis in a wide variety of organs, including the heart, liver, kidneys, and spleen. parenchymal organs, including heart, liver, kidney, and spleen, play important roles in the development of fibrosis. These findings elucidate the intricate involvement of the lncRNA/circRNA-miRNA-mRNA axis in the pathophysiological processes underpinning organ fibrosis, thereby enhancing our comprehension of the onset and progression of this condition. Furthermore, they introduce novel potential therapeutic targets within the realm of ncRNA-based therapeutics, offering avenues for the development of innovative drugs aimed at mitigating or reversing the effects of organ fibrosis.

Revisiting the role of MicroRNAs in the pathogenesis of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a prevalent chronic pulmonary fibrosis disease characterized by alveolar epithelial cell damage, fibroblast proliferation and activation, excessive extracellular matrix deposition, and abnormal epithelial-mesenchymal transition (EMT), resulting in tissue remodeling and irreversible structural distortion. The mortality rate of IPF is very high, with a median survival time of 2-3 years after diagnosis. The exact cause of IPF remains unknown, but increasing evidence supports the central role of epigenetic changes, particularly microRNA (miRNA), in IPF. Approximately 10% of miRNAs in IPF lung tissue exhibit differential expression compared to normal lung tissue. Diverse miRNA phenotypes exert either a pro-fibrotic or anti-fibrotic influence on the progression of IPF. In the context of IPF, epigenetic factors such as DNA methylation and long non-coding RNAs (lncRNAs) regulate differentially expressed miRNAs, which in turn modulate various signaling pathways implicated in this process, including transforming growth factor-β1 (TGF-β1)/Smad, mitogen-activated protein kinase (MAPK), and phosphatidylinositol-3-kinase/protein kinase B (PI3K/AKT) pathways. Therefore, this review presents the epidemiology of IPF, discusses the multifaceted regulatory roles of miRNAs in IPF, and explores the impact of miRNAs on IPF through various pathways, particularly the TGF-β1/Smad pathway and its constituent structures. Consequently, we investigate the potential for targeting miRNAs as a treatment for IPF, thereby contributing to advancements in IPF research.

Effects of Natural Products through Inhibiting Endoplasmic Reticulum Stress on Attenuation of Idiopathic Pulmonary Fibrosis

With ever-increasing intensive studies of idiopathic pulmonary fibrosis (IPF), significant progresses have been made. Endoplasmic reticulum stress (ERS)/unfolded protein reaction (UPR) is associated with the development and progression of IPF, and targeting ERS/UPR may be beneficial in the treatment of IPF. Natural product is a tremendous source of new drug discovery, and accumulating studies have reported that many natural products show potential therapeutic effects for IPF via modulating one or more branches of the ERS signaling pathway. Therefore, this review focuses on critical roles of ERS in IPF development, and summarizes herbal preparations and bioactive compounds which protect against IPF through regulating ERS.

A transcriptomics-based investigation of the mechanism of pulmonary fibrosis induced by nickel oxide nanoparticles

Nickel oxide nanoparticles (NiONPs) are an emerging nanomaterial, which poses a huge threat to the health of workplace population. Nanoparticles induce pulmonary fibrosis, and its mechanisms are associated with noncoding RNAs (ncRNAs). However, ncRNAs and competing endogenous RNA (ceRNA) networks which involved in NiONP-induced pulmonary fibrosis are still unclear. This study aimed to identify ncRNA-related ceRNA networks and investigate the role of the Wnt/β-catenin pathway in pulmonary fibrosis. Male Wistar rats were intratracheally instilled with 0.015, 0.06, and 0.24 mg/kg NiONPs twice a week for 9 weeks. First, we found there were 93 circularRNAs (circRNAs), 74 microRNAs (miRNAs), 124 long non-coding RNAs (lncRNAs), and 1675 messenger RNAs (mRNAs) differentially expressed through microarray analysis. Second, we constructed ceRNA networks among lncRNAs/circRNAs, miRNAs and mRNAs and identified two ceRNA networks (lncMelttl16/miR-382-5p/Hsd17b7 and circIqch/miR-181d-5p/Stat1) after real time-quantitative polymerase chain reaction (RT-qPCR) validation. Furthermore, based on Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses, ncRNAs were found to be involved in biological processes and signaling pathways related to pulmonary fibrosis. KEGG analysis showed that NiONPs activated the Wnt/β-catenin pathway in rats. In vitro, HFL1 cells were treated with 0, 50, 100, and 200 μg/mL NiONPs for 24 h. We found that NiONPs induced collagen deposition and Wnt/β-catenin pathway activation. Moreover, a blockade of Wnt/β-catenin pathway alleviated NiONP-induced collagen deposition. In conclusion, these observations suggested that ncRNAs were crucial in pulmonary fibrosis development and that the Wnt/β-catenin pathway mediated the deposition of collagen.

Genetic deficiency of the transcription factor NFAT1 confers protection against fibrogenic responses independent of immune influx

Idiopathic pulmonary fibrosis (IPF) is marked by unremitting matrix deposition and architectural distortion. Multiple profibrotic pathways contribute to the persistent activation of mesenchymal cells (MCs) in fibrosis, highlighting the need to identify and target common signaling pathways. The transcription factor nuclear factor of activated T cells 1 (NFAT1) lies downstream of second messenger calcium signaling and has been recently shown to regulate key profibrotic mediator autotaxin (ATX) in lung MCs. Herein, we investigate the role of NFAT1 in regulating fibroproliferative responses during the development of lung fibrosis. Nfat1-/--deficient mice subjected to bleomycin injury demonstrated improved survival and protection from lung fibrosis and collagen deposition as compared with bleomycin-injured wild-type (WT) mice. Chimera mice, generated by reconstituting bone marrow cells from WT or Nfat1-/- mice into irradiated WT mice (WT→WT and Nfat1-/-→WT), demonstrated no difference in bleomycin-induced fibrosis, suggesting immune influx-independent fibroprotection in Nfat1-/- mice. Examination of lung tissue and flow sorted lineageneg/platelet-derived growth factor receptor alpha (PDGFRα)pos MCs demonstrated decreased MC numbers, proliferation [↓ cyclin D1 and 5-ethynyl-2'-deoxyuridine (EdU) incorporation], myofibroblast differentiation [↓ α-smooth muscle actin (α-SMA)], and survival (↓ Birc5) in Nfat1-/- mice. Nfat1 deficiency abrogated ATX expression in response to bleomycin in vivo and MCs derived from Nfat1-/- mice demonstrated decreased ATX expression and migration in vitro. Human IPF MCs demonstrated constitutive NFAT1 activation, and regulation of ATX in these cells by NFAT1 was confirmed using pharmacological and genetic inhibition. Our findings identify NFAT1 as a critical mediator of profibrotic processes, contributing to dysregulated lung remodeling and suggest its targeting in MCs as a potential therapeutic strategy in IPF.NEW & NOTEWORTHY Idiopathic pulmonary fibrosis (IPF) is a fatal disease with hallmarks of fibroblastic foci and exuberant matrix deposition, unknown etiology, and ineffective therapies. Several profibrotic/proinflammatory pathways are implicated in accelerating tissue remodeling toward a honeycombed end-stage disease. NFAT1 is a transcriptional factor activated in IPF tissues. Nfat1-deficient mice subjected to chronic injury are protected against fibrosis independent of immune influxes, with suppression of profibrotic mesenchymal phenotypes including proliferation, differentiation, resistance to apoptosis, and autotaxin-related migration.

A mechanism by which gut microbiota elevates permeability and inflammation in obese/diabetic mice and human gut

OBJECTIVE

Ample evidence exists for the role of abnormal gut microbiota composition and increased gut permeability ('leaky gut') in chronic inflammation that commonly co-occurs in the gut in both obesity and diabetes, yet the detailed mechanisms involved in this process have remained elusive.

DESIGN

In this study, we substantiate the causal role of the gut microbiota by use of faecal conditioned media along with faecal microbiota transplantation. Using untargeted and comprehensive approaches, we discovered the mechanism by which the obese microbiota instigates gut permeability, inflammation and abnormalities in glucose metabolism.

RESULTS

We demonstrated that the reduced capacity of the microbiota from both obese mice and humans to metabolise ethanolamine results in ethanolamine accumulation in the gut, accounting for induction of intestinal permeability. Elevated ethanolamine increased the expression of microRNA-miR-101a-3p by enhancing ARID3a binding on the miR promoter. Increased miR-101a-3p decreased the stability of zona occludens-1 (Zo1) mRNA, which in turn, weakened intestinal barriers and induced gut permeability, inflammation and abnormalities in glucose metabolism. Importantly, restoring ethanolamine-metabolising activity in gut microbiota using a novel probiotic therapy reduced elevated gut permeability, inflammation and abnormalities in glucose metabolism by correcting the ARID3a/miR-101a/Zo1 axis.

CONCLUSION

Overall, we discovered that the reduced capacity of obese microbiota to metabolise ethanolamine instigates gut permeability, inflammation and glucose metabolic dysfunctions, and restoring ethanolamine-metabolising capacity by a novel probiotic therapy reverses these abnormalities.

TRIAL REGISTRATION NUMBER

NCT02869659 and NCT03269032.

MicroRNA-9-1 Attenuates Influenza A Virus Replication via Targeting Tankyrase 1

An unstable influenza genome leads to the virus resistance to antiviral drugs that target viral proteins. Thus, identification of host factors essential for virus replication may pave the way to develop novel antiviral therapies. In this study, we investigated the roles of the poly(ADP-ribose) polymerase enzyme, tankyrase 1 (TNKS1), and the endogenous small noncoding RNA, miR-9-1, in influenza A virus (IAV) infection. Increased expression of TNKS1 was observed in IAV-infected human lung epithelial cells and mouse lungs. TNKS1 knockdown by RNA interference repressed influenza viral replication. A screen using TNKS1 3'-untranslation region (3'-UTR) reporter assays and predicted microRNAs identified that miR-9-1 targeted TNKS1. Overexpression of miR-9-1 reduced influenza viral replication in lung epithelial cells as measured by viral mRNA and protein levels as well as virus production. miR-9-1 induced type I interferon production and enhanced the phosphorylation of STAT1 in cell culture. The ectopic expression of miR-9-1 in the lungs of mice by using an adenoviral viral vector enhanced type I interferon response, inhibited viral replication, and reduced susceptibility to IAV infection. Our results indicate that miR-9-1 is an anti-influenza microRNA that targets TNKS1 and enhances cellular antiviral state.

Cellular microRNAs target SARS-CoV-2 spike protein and restrict viral replication

MicroRNAs (miRNAs) regulate gene expression posttranscriptionally and are implicated in viral replication and host tropism. miRNAs can impact the viruses either by directly interacting with the viral genome or modulating host factors. Although many miRNAs have predicted binding sites in the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) viral RNA genome, little experimental validation has been done. We first identified 492 miRNAs that have binding site(s) on the spike (S) viral RNA by a bioinformatics prediction. We then validated the selected 39 miRNAs by examining S-protein levels after coexpressing the S-protein and a miRNA into the cells. Seven miRNAs were found to reduce the S-protein levels by more than 50%. Among them, miR-15a, miR-153, miR-298, miR-508, miR-1909, and miR-3130 also significantly reduced SARS-CoV-2 viral replication. SARS-CoV-2 infection decreased the expression levels of miR-298, miR-497, miR-508, miR-1909, and miR-3130, but had no significant effects on miR-15a and miR-153 levels. Intriguingly, the targeting sequences of these miRNAs on the S viral RNA showed sequence conservation among the variants of concern. Our results suggest that these miRNAs elicit effective antiviral defense against SARS-CoV-2 by modulating S-protein expression and are likely targeting all the variants. Thus, the data signify the therapeutic potential of miRNA-based therapy for SARS-CoV-2 infections.NEW & NOTEWORTHY MicroRNAs can impact viruses either by directly interacting with the virus genome or by modulating host factors. We identified that cellular miRNAs regulate effective antiviral defense against SARS-CoV-2 via modulating spike protein expression, which may offer a potential candidate for antiviral therapy.

Delivery of anti-microRNA-21 by lung-targeted liposomes for pulmonary fibrosis treatment

Idiopathic pulmonary fibrosis (IPF) is a chronic lung disorder with a low survival rate. Pulmonary fibrosis is one of the complications of COVID-19 and has a high prevalence in COVID-19 patients. Currently, no effective therapies other than lung transplantation are available to cure IPF and post-COVID-19 pulmonary fibrosis. MicroRNAs are small non-coding RNAs that mediate the development and progression of pulmonary fibrosis, thus making them potent drug candidates for this serious disease. MicroRNA-21 (miR-21) promotes not only the differentiation of fibroblasts to myofibroblasts but also epithelial-mesenchymal transition, both of which have been proposed as fundamental processes in pulmonary fibrosis development. Delivery of anti-miR-21 to block the miR-21-associated fibrogenic pathways represents a promising therapy for pulmonary fibrosis. However, microRNA treatment is challenged by quick degradation of RNA in blood, poor cellular uptake, and off-target effects. To overcome these challenges, we developed a lung-targeted, cationic liposome formulation to encapsulate anti-miR-21, enhance its delivery efficiency, and improve the therapeutic efficacy. We optimized the liposome formulation and demonstrated the anti-fibrotic effects using both in vitro and in vivo lung fibrosis models. Our results showed that anti-miR-21 delivered by cationic liposomes suppressed myofibroblast differentiation, reduced the synthesis of extracellular matrix, and inhibited fibrosis progression.

Downregulation of fibrosis related hsa-miR-29c-3p in human CAKUT

Congenital anomalies of the kidney and urinary tract (CAKUT) represent structural and functional urinary system malformations and take place as one of the most common congenital malformations with an incidence of 1:500. Ureteral obstruction-induced hydronephrosis is associated with renal fibrosis and chronic kidney diseases in the pediatric CAKUT. We aimed to construct interaction network of previously bioinformatically associated miRNAs with CAKUT differentially expressed genes in order to prioritize those associated with fibrotic process and to experimentally validate the expression of selected miRNAs in CAKUT patients compared to control group. We constructed interaction network of hsa-miR-101-3p, hsa-miR-101-5p and hsa-miR-29c-3p that showed significant association with fibrosis. The top enriched molecular pathway was extracellular matrix-receptor interaction (adjusted p = .0000263). We experimentally confirmed expression of three miRNAs (hsa-miR-29c-3p, hsa-miR-101-3p and hsa-miR-101-5p) in obstructed ureters (ureteropelvic junction obstruction and primary obstructive megaureter) and vesicoureteral reflux. The hsa-miR-29c-3p was shown to have lower expression in both patient groups compared to controls. Relative levels of hsa-miR-101-5p and hsa-miR-101-3p showed significant positive correlations in both groups of patients. Statistically significant correlation was observed between hsa-miR-101 (-3p and -5p) and hsa-miR-29c-3p only in the obstructed group. The significant downregulation of anti-fibrotic hsa-miR-29c-3p in obstructive CAKUT could explain activation of genes involved in fibrotic processes. As miRNAs are promising candidates in therapeutic approaches our results need further measurement of fibrotic markers or assessment of extent of fibrosis and functional evaluation of hsa-miR-29c.

Systematic review of overlapping microRNA patterns in COVID-19 and idiopathic pulmonary fibrosis

BACKGROUND

Pulmonary fibrosis is an emerging complication of SARS-CoV-2 infection. In this study, we speculate that patients with COVID-19 and idiopathic pulmonary fibrosis (IPF) may share aberrant expressed microRNAs (miRNAs) associated to the progression of lung fibrosis.

OBJECTIVE

To identify miRNAs presenting similar alteration in COVID-19 and IPF, and describe their impact on fibrogenesis.

METHODS

A systematic review of the literature published between 2010 and January 2022 (PROSPERO, CRD42022341016) was conducted using the key words (COVID-19 OR SARS-CoV-2) AND (microRNA OR miRNA) or (idiopathic pulmonary fibrosis OR IPF) AND (microRNA OR miRNA) in Title/Abstract.

RESULTS

Of the 1988 references considered, 70 original articles were appropriate for data extraction: 27 studies focused on miRNAs in COVID-19, and 43 on miRNAs in IPF. 34 miRNAs were overlapping in COVID-19 and IPF, 7 miRNAs presenting an upregulation (miR-19a-3p, miR-200c-3p, miR-21-5p, miR-145-5p, miR-199a-5p, miR-23b and miR-424) and 9 miRNAs a downregulation (miR-17-5p, miR-20a-5p, miR-92a-3p, miR-141-3p, miR-16-5p, miR-142-5p, miR-486-5p, miR-708-3p and miR-150-5p).

CONCLUSION

Several studies reported elevated levels of profibrotic miRNAs in COVID-19 context. In addition, the balance of antifibrotic miRNAs responsible of the modulation of fibrotic processes is impaired in COVID-19. This evidence suggests that the deregulation of fibrotic-related miRNAs participates in the development of fibrotic lesions in the lung of post-COVID-19 patients.

Perspective for Studying the Relationship of miRNAs with Transposable Elements

Transposable elements are important sources of miRNA, long non-coding RNAs genes, and their targets in the composition of protein-coding genes in plants and animals. Therefore, the detection of expression levels of specific non-coding RNAs in various tissues and cells in normal and pathological conditions may indicate a programmed pattern of transposable elements' activation. This reflects the species-specific composition and distribution of transposable elements in genomes, which underlie gene regulation in every cell division, including during aging. TEs' expression is also regulated by epigenetic factors (DNA methylation, histone modifications), SIRT6, cytidine deaminases APOBEC3, APOBEC1, and other catalytic proteins, such as ERCC, TREX1, RB1, HELLS, and MEGP2. In evolution, protein-coding genes and their regulatory elements are derived from transposons. As part of non-coding regions and introns of genes, they are sensors for transcriptional and post-transcriptional control of expression, using miRNAs and long non-coding RNAs, that arose from transposable elements in evolution. Methods (Orbld, ncRNAclassifier) and databases have been created for determining the occurrence of miRNAs from transposable elements in plants (PlanTE-MIR DB, PlaNC-TE), which can be used to design epigenetic gene networks in ontogenesis. Based on the data accumulated in the scientific literature, the presence of 467 transposon-derived miRNA genes in the human genome has been reliably established. It was proposed to create an updated and controlled online bioinformatics database of miRNAs derived from transposable elements in healthy individuals, as well as expression changes of these miRNAs during aging and various diseases, such as cancer and difficult-to-treat diseases. The use of the information obtained can open new horizons in the management of tissue and organ differentiation to aging slow down. In addition, the created database could become the basis for clarifying the mechanisms of pathogenesis of various diseases (imbalance in the activity of transposable elements, reflected in changes in the expression of miRNAs) and designing their targeted therapy using specific miRNAs as targets. This article provides examples of the detection of transposable elements-derived miRNAs involved in the development of specific malignant neoplasms, aging, and idiopathic pulmonary fibrosis.

The molecular mechanisms of remodeling in asthma, COPD and IPF with a special emphasis on the complex role of Wnt5A

INTRODUCTION

Chronic inflammatory lung diseases are a common cause of suffering and death. Chronic obstructive pulmonary disease (COPD) is the reason for 6% of all deaths worldwide. A total of 262 million people are affected by asthma and 461,000 people died in 2019. Idiopathic pulmonary fibrosis (IPF) is diagnosed in 3 million people worldwide, with an onset over the age of 50 with a mean survival of only 24-30 months. These three diseases have in common that remodeling of the lung tissue takes place, which is responsible for an irreversible decline of lung function. Pathological lung remodeling is mediated by a complex interaction of different, often misguided, repair processes regulated by a variety of mediators. One group of these, as has recently become known, are the Wnt ligands. In addition to their well-characterized role in embryogenesis, this group of glycoproteins is also involved in immunological and structural repair processes. Depending on the combination of the Wnt ligand with its receptors and co-receptors, canonical and noncanonical signaling cascades can be induced. Wnt5A is a mediator that is described mainly in noncanonical Wnt signaling and has been shown to play an important role in different inflammatory diseases and malignancies.

OBJECTIVES

In this review, we summarize the literature available regarding the role of Wnt5A as an immune modulator and its role in the development of asthma, COPD and IPF. We will focus specifically on what is known about Wnt5A concerning its role in the remodeling processes involved in the chronification of the diseases.

CONCLUSION

Wnt5A has been shown to be involved in all three inflammatory lung diseases. Since the ligand affects both structural and immunological processes, it is an interesting target for the treatment of lung diseases whose pathology involves a restructuring of the lung tissue triggered in part by an inflammatory immune response.

E2F1 regulates miR-215-5p to aggravate paraquat-induced pulmonary fibrosis via repressing BMPR2 expression

Background

Pulmonary fibrosis is considered to be an irreversible lung injury, which can be caused by paraquat (PQ) poisoning. MiRNAs have been demonstrated crucial roles in pulmonary fibrosis caused by numerous approaches including PQ induction. The purpose of this study was to investigate the role and the underlying mechanism of miR-215 in PQ-induced pulmonary fibrosis.

Methods

The cell and animal models of pulmonary fibrosis were established through PQ intervention. Cell viability was performed to test by MTT assay. Immunofluorescence assay was used to detect COL1A1 expression and its location. The relationships among E2F1, miR-215-5p, and BMPR2 were validated by dual luciferase reporter gene assay, chromatin immunoprecipitation and RNA-binding protein immunoprecipitation. Lung morphology was evaluated by hematoxylin and eosin staining.

Results

MiR-215-5p was upregulated in PQ-induced pulmonary fibrosis in vitro and in vivo. MiR-215-5p silencing relieved PQ-induced pulmonary fibrosis progression by enhancing cell viability and reducing the expression of fibrosis-related markers (COL1A1, COL3A1, and α-SMA). Mechanistically, miR-215-5p directly targeted BMRP2. BMPR2 knockdown abolished the suppressive effects of miR-215-5p knockdown on PQ-induced pulmonary fibrosis. In addition, E2F1 interacted with miR-215-5p promoter and positively regulated miR-215-5p expression. E2F1 downregulation reduced miR-215-5p level and promoted BMPR2 level via regulating TGF-β/Smad3 pathway, and then suppressed PQ-induced pulmonary fibrosis, whereas these effects were compromised by miR-215-5p sufficiency.

Conclusion

MiR-215-5p was activated by E2F1 to repress BMPR2 expression and activate TGF-β/Smad3 pathway, which aggravated PQ-induced pulmonary fibrosis progression. Targeting the E2F1/miR-215-5p/BMPR2 axis might be a new approach to alleviate PQ-induced pulmonary fibrosis.

A lung targeted miR-29 mimic as a therapy for pulmonary fibrosis

BACKGROUND

MicroRNAs are non-coding RNAs that negatively regulate gene networks. Previously, we reported that systemically delivered miR-29 mimic MRG-201 reduced fibrosis in animal models, supporting the consideration of miR-29-based therapies for idiopathic pulmonary fibrosis (IPF).

METHODS

We generated MRG-229, a next-generation miR-29 mimic based on MRG-201 with improved chemical stability due to additional sugar modifications and conjugation with the internalization moiety BiPPB (PDGFbetaR-specific bicyclic peptide)1. We investigated the anti-fibrotic efficacy of MRG-229 on TGF-β1 treated human lung fibroblasts (NHLFs), human precision cut lung slices (hPCLS), and in vivo bleomycin studies; toxicology was assessed in two animal models, rats, and non-human primates. Finally, we examined miR-29b levels in a cohort of 46 and 213 patients with IPF diagnosis recruited from Yale and Nottingham Universities (Profile Cohort), respectively.

FINDINGS

The peptide-conjugated MRG-229 mimic decreased expression of pro-fibrotic genes and reduced collagen production in each model. In bleomycin-treated mice, the peptide-conjugated MRG-229 mimic downregulated profibrotic gene programs at doses more than ten-fold lower than the original compound. In rats and non-human primates, the peptide-conjugated MRG-229 mimic was well tolerated at clinically relevant doses with no adverse findings observed. In human peripheral blood from IPF patients decreased miR-29 concentrations were associated with increased mortality in two cohorts potentially identified as a target population for treatment.

INTERPRETATION

Collectively, our results provide support for the development of the peptide-conjugated MRG-229 mimic as a potential therapy in humans with IPF.

FUNDING

This work was supported by NIH NHLBI grants UH3HL123886, R01HL127349, R01HL141852, U01HL145567.

Silencing lncRNA Snhg6 mitigates bleomycin-induced pulmonary fibrosis in mice via miR-26a-5p/TGF-β1-smads axis

Idiopathic pulmonary fibrosis (IPF) is an interstitial pulmonary disease with slow onset and high mortality. Epithelial-mesenchymal transition (EMT) is a significant condition for tissue fibrosis, and lncRNA-Snhg6 (small nucleolar RNA host gene 6) is related to EMT in some cancer cells, but its role in pulmonary fibrosis remains obscure. Here, we found that TGF-β1 and Snhg6 were up-regulated in lung tissues of BLM-induced lung fibrosis mouse, and Snhg6 expression was significantly increased in primary lung fibroblasts after BLM treatment. Snhg6 knockdown notably alleviated the pulmonary dysfunction, and the increase of fibrosis area and collagen deposition induced by BLM. MiR-26a-5p was downregulated in BLM-induced fibrotic lung tissues, and it was negatively regulated by Snhg6. Silencing Snhg6 markedly alleviated the TGF-β1-induced increase in fibrotic marker expression, cell proliferation, migration and differentiation, as well as the nuclear transport of p-Smad2/3 by modulating miR-26a-5p expression in mouse lung fibroblasts. Moreover, overexpressing Snhg6-induced collagen accumulation and fibroblast activation in fibroblasts, which was reversed by treatment with miR-26a-5p mimic or oxymatrine (an inhibitor of TGF-β1-Smads pathway). Interestingly, silencing Snhg6 in vivo mitigated BLM-driven pulmonary fibrosis by regulating the miR-26a-5p/TGF-β1-Smads axis. Our data revealed that Snhg6 contributed to the process of BLM-driven lung fibrosis in mouse by modulating the miR-26a-5p/TGF-β1-Smads axis, suggesting that Snhg6 might be a therapeutic target for lung fibrosis.

Emerging role of different DNA methyltransferases in the pathogenesis of cancer

DNA methylation is one of the most essential epigenetic mechanisms to regulate gene expression. DNA methyltransferases (DNMTs) play a vital role in DNA methylation in the genome. In mammals, DNMTs act with some elements to regulate the dynamic DNA methylation patterns of embryonic and adult cells. Conversely, the aberrant function of DNMTs is frequently the hallmark in judging cancer, including total hypomethylation and partial hypermethylation of tumor suppressor genes (TSGs), which improve the malignancy of tumors, aggravate the ailment for patients, and significantly exacerbate the difficulty of cancer therapy. Since DNA methylation is reversible, currently, DNMTs are viewed as an important epigenetic target for drug development. However, the impression of DNMTs on cancers is still controversial, and therapeutic methods targeting DNMTs remain under exploration. This review mainly summarizes the relationship between the main DNMTs and cancers as well as regulatory mechanisms and clinical applications of DNMTs in cancer and highlights several forthcoming strategies for targeting DNMTs.

RNF2 mediates pulmonary fibroblasts activation and proliferation by regulating mTOR and p16-CDK4-Rb1 signaling pathway

BACKGROUND

Pulmonary fibrosis (PF) is a chronic, progressive interstitial lung disease with unknown etiology, associated with increasing morbidity and pessimistic prognosis. Pulmonary fibroblasts (PFbs) are the key effector cells of PF, in which abnormal activation and proliferation is an important pathogenesis of PF. Ring finger protein 2 (RNF2), is identified as the catalytic subunit of poly-comb repressive complex 1, which is closely related to occurrence and development of lung cancer, but its function in PF has not been revealed. In this paper, we sought to identify the regulatory role of RNF2 in lung fibrogenesis and its underlying mechanisms.

METHODS

The expression of RNF2 in lung fibrosis tissue (human and Bleomycin-induced mouse) and cell model (TGF-β1-induced HFL1 cells) was examined by immunoblotting analysis and immunofluorescence. Western blot, qRT-PCR were performed to evaluate the expression of pro-fibrogenic cytokines (including α-SMA, ECM and MMPs/ TIMPs) induced by TGF-β1 in HFL1 cells. Cell proliferation, cycle progression and apoptosis were examined by fow cytometric. Molecular interactions were tested by Co-IP assays.

RESULTS

RNF2 expression was elevated in PF tissues compared to normal adjacent tissues and in PFbs (HFL1) induced by TGF-β1. Furthermore, knockdown of RNF2 could evidently inhibit the abnormal expression of pro-fibrogenic cytokines (including α-SMA, ECM and MMPs/TIMPs) induced by TGF-β1 in HFL1 cells. Functionally, RNF2 silencing could significantly suppress TGF-β1-induced anomalous proliferation, cell cycle progression, apoptosis and autophagy in HFL1 cells. Mechanistically, RNF2 deficiency could effectively inhibit the abnormal activation of mTOR signaling pathway in TGF-β1-induced HFL1 cells, and mTOR pathway had feedback regulation on the expression of RNF2. Further studies RNF2 could regulate the phosphorylation level of RB1 through interacting with p16 to destroy the binding of p16 and CDK4 competitively. Simultaneously, overexpression of RNF2 could show the opposite results.

CONCLUSIONS

These results indicated that RNF2 is a potent pro-fibrogenic molecule for PFbs activation and proliferation through mTOR and p16-CDK4-Rb signaling pathways, and RNF2 inhibition will be a potential therapeutic avenue for treating PF.

Comprehensive Analysis of Potential ceRNA Network and Different Degrees of Immune Cell Infiltration in Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) is a leading cause of death in critically ill patients due to hypoxemic respiratory failure. The specific pathogenesis underlying ARDS has not been fully elucidated. In this study, we constructed a triple regulatory network involving competing endogenous RNA (ceRNA) to investigate the potential mechanism of ARDS and evaluated the immune cell infiltration patterns in ARDS patients. Overall, we downloaded three microarray datasets that included 60 patients with sepsis-induced ARDS and 79 patients with sepsis alone from the public Gene Expression Omnibus (GEO) database and identified differentially expressed genes (DEGs, including 9 DElncRNAs, 9 DEmiRNAs, and 269 DEmRNAs) by R software. The DEGs were subjected to the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) for functional enrichment analysis, and a protein–protein interaction (PPI) network was generated for uncovering interactive relationships among DEmRNAs. Then, a ceRNA network that contained 5 DElncRNAs, 7 DEmiRNAs, and 71 DEmRNAs was established according to the overlapping genes in both DEGs and predicted genes by public databases. Finally, we identified the TUG1/miR-140-5p/NFE2L2 pathway as the hub pathway in the whole network through Cytoscape. In addition, we evaluated the distribution of 22 subtypes of immune cells and recognized three differentially expressed immune cells in patients with sepsis-induced ARDS by “Cell Type Identification by Estimating Relative Subsets of Known RNA Transcripts (CIBERSORT)” algorithm, namely, naive B cells, regulatory T cells, and eosinophils. Correlations between differentially expressed immune cells and hub genes in the ceRNA network were also performed. In conclusion, we demonstrated a new potential regulatory mechanism underlying ARDS (the TUG1/miR-140-5p/NFE2L2 ceRNA regulatory pathway), which may help in further exploring the pathogenesis of ARDS.

lncRNA NEAT1 promotes hypoxia-induced inflammation and fibrosis of alveolar epithelial cells via targeting miR-29a/NFATc3 axis

The objective of the present study was to explore the function and mechanism of long noncoding RNA (lncRNA) nuclear paraspeckle assembly transcript 1 (NEAT1) in pulmonary fibrosis (PF) progression. HPAEpic cells and A549 cells were exposed to hypoxic conditions to establish an in vitro model. Cell apoptosis was detected by TUNEL assay, and inflammatory cytokine levels were detected by ELISA. Gene and protein expression levels were identified by qRT-PCR and Western blot assays, respectively. The interaction among NEAT1, miR-29a, and NFATc3 was identified by dual-luciferase reporter and RNA pull-down assays. In hypoxia-treated cells, hypoxia markers (HIF-1α and HIF-2α), cytokines (TNF-α, IL-1β, and IL-6) and fibrotic markers (α-SMA, collagen I and collagen III) were significantly enhanced. Consistently, the expression levels of NEAT1 and NFATc3 were increased, but miR-29a was decreased in hypoxia-stimulated cells. Knockdown of NEAT1 significantly decreased cell apoptosis and the releases of TNF-α, IL-1β, and IL-6 as well as reduced the levels of α-SMA, collagen I, and collagen III. Moreover, NEAT1 positively regulated NFATc3 expression by directly targeting miR-29a. Functional experiments showed that the anti-apoptotic, anti-inflammatory, and anti-fibrotic effects mediated by NETA1 silencing were impeded by miR-29a inhibition or NFATc3 overexpression in hypoxia-stimulated HPAEpic and A549 cells. Collectively, these data demonstrated that NEAT1 knockdown inhibited hypoxia-induced cell apoptosis, inflammation, and fibrosis by targeting the miR-29a/NFATc3 axis in PF, suggesting that NEAT1 might be a potential therapeutic target for relieving PF progression.

Role of MicroRNAs in Signaling Pathways Associated with the Pathogenesis of Idiopathic Pulmonary Fibrosis: A Focus on Epithelial-Mesenchymal Transition

Idiopathic pulmonary fibrosis (IPF) is a chronic and progressive disease with high mortality and unclear etiology. Previous evidence supports that the origin of this disease is associated with epigenetic alterations, age, and environmental factors. IPF initiates with chronic epithelial lung injuries, followed by basal membrane destruction, which promotes the activation of myofibroblasts and excessive synthesis of extracellular matrix (ECM) proteins, as well as epithelial-mesenchymal transition (EMT). Due to miRNAs’ role as regulators of apoptosis, proliferation, differentiation, and cell-cell interaction processes, some studies have involved miRNAs in the biogenesis and progression of IPF. In this context, the analysis and discussion of the probable association of miRNAs with the signaling pathways involved in the development of IPF would improve our knowledge of the associated molecular mechanisms, thereby facilitating its evaluation as a therapeutic target for this severe lung disease. In this work, the most recent publications evaluating the role of miRNAs as regulators or activators of signal pathways associated with the pathogenesis of IPF were analyzed. The search in Pubmed was made using the following terms: “miRNAs and idiopathic pulmonary fibrosis (IPF)”; “miRNAs and IPF and signaling pathways (SP)”; and “miRNAs and IPF and SP and IPF pathogenesis”. Additionally, we focus mainly on those works where the signaling pathways involved with EMT, fibroblast differentiation, and synthesis of ECM components were assessed. Finally, the importance and significance of miRNAs as potential therapeutic or diagnostic tools for the treatment of IPF are discussed.

Molecular genetics of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a severe progressive interstitial lung disease with a prevalence of 2 to 29 per 100,000 of the world’s population. Aging is a significant risk factor for IPF, and the mechanisms of aging (telomere depletion, genomic instability, mitochondrial dysfunction, loss of proteostasis) are involved in the pathogenesis of IPF. The pathogenesis of IPF consists of TGF-β activation, epithelial-mesenchymal transition, and SIRT7 expression decrease. Genetic studies have shown a role of mutations and polymorphisms in mucin genes (MUC5B), in the genes responsible for the integrity of telomeres (TERC, TERC, TINF2, DKC1, RTEL1, PARN), in surfactant-related genes (SFTPC, SFTPCA, SFTPA2, ABCA3, SP-A2), immune system genes (IL1RN, TOLLIP), and haplotypes of HLA genes (DRB1*15:01, DQB1*06:02) in IPF pathogenesis. The investigation of the influence of reversible epigenetic factors on the development of the disease, which can be corrected by targeted therapy, shows promise. Among them, an association of a number of specific microRNAs and long noncoding RNAs was revealed with IPF. Therefore, dysregulation of transposons, which serve as key sources of noncoding RNA and affect mechanisms of aging, may serve as a driver for IPF development. This is due to the fact that pathological activation of transposons leads to violation of the regulation of genes, in the epigenetic control of which microRNA originating from these transposons are involved (due to the complementarity of nucleotide sequences). Analysis of the MDTE database (miRNAs derived from Transposable Elements) allowed the detection of 12 different miRNAs derived in evolution from transposons and associated with IPF (miR-31, miR-302, miR-326, miR-335, miR-340, miR-374, miR-487, miR-493, miR-495, miR-630, miR-708, miR-1343). We described the relationship of transposons with TGF-β, sirtuins and telomeres, dysfunction of which is involved in the pathogenesis of IPF. New data on IPF epigenetic mechanisms can become the basis for improving results of targeted therapy of the disease using noncoding RNAs.

MicroRNAs: master regulators in host-parasitic protist interactions

MicroRNAs (miRNAs) are a group of small non-coding RNAs present in a wide diversity of organisms. MiRNAs regulate gene expression at a post-transcriptional level through their interaction with the 3' untranslated regions of target mRNAs, inducing translational inhibition or mRNA destabilization and degradation. Thus, miRNAs regulate key biological processes, such as cell death, signal transduction, development, cellular proliferation and differentiation. The dysregulation of miRNAs biogenesis and function is related to the pathogenesis of diseases, including parasite infection. Moreover, during host-parasite interactions, parasites and host miRNAs determine the probability of infection and progression of the disease. The present review is focused on the possible role of miRNAs in the pathogenesis of diseases of clinical interest caused by parasitic protists. In addition, the potential role of miRNAs as targets for the design of drugs and diagnostic and prognostic markers of parasitic diseases is also discussed.

The interaction between ETS transcription factor family members and microRNAs: A novel approach to cancer therapy

In cancer biology, ETS transcription factors promote tumorigenesis by mediating transcriptional regulation of numerous genes via the conserved ETS DNA-binding domain. MicroRNAs (miRNAs) act as posttranscriptional regulators to regulate various tumor-promoting or tumor-suppressing factors. Interactions between ETS factors and miRNAs regulate complex tumor-promoting and tumor-suppressing networks. This review discusses the progress of ETS factors and miRNAs in cancer research in detail. We focused on characterizing the interaction of the miRNA/ETS axis with competing endogenous RNAs (ceRNAs) and its regulation in posttranslational modifications (PTMs) and the tumor microenvironment (TME). Finally, we explore the prospect of ETS factors and miRNAs in therapeutic intervention. Generally, interactions between ETS factors and miRNAs provide fresh perspectives into tumorigenesis and development and novel therapeutic approaches for malignant tumors.

Vincristine Promotes Transdifferentiation of Fibroblasts Into Myofibroblasts via P38 and ERK Signal Pathways

Background: Vincristine (VCR) is used in the clinic as an anti-tumor drug. VCR can cause pulmonary fibrosis (PF), leading to respiratory failure. The transformation of fibroblasts into myofibroblasts may play a key role in PF. The present study attempted to reveal the molecular mechanism of VCR-induced PF and the possible involvement of the mitogen-activated protein kinase (MAPK) signaling pathway.

Methods: Human embryonic lung fibroblasts (HELFs) were treated with different concentrations of VCR. Inhibitors of extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 MAPK were added to HELFs. Cell proliferation state was assessed using cell counting kit-8 and by directly counting the number of cells. The expressions of vimentin and α-smooth muscle actin (α-SMA) were investigated using western blot and immunofluorescence analyses. Activation of ERK and P38 was estimated by the expression of phosphorylated p38 MAPK (p-p38), p38 MAPK, phosphorylated ERK1/2 (p-ERK1/2) and ERK1/2 using western blot analysis. Enzyme-linked immunosorbent assay was used to estimate the level of collagen I in cell culture supernatants.

Results: Results showed that VCR promoted cellular proliferation, secretion of collagen I and the expression of vimentin and α-SMA. High expression of p-p38 and p-ERK1/2 was associated with the activation of the MAPK signaling pathway. MAPK inhibitors SB203580 and PD98059 suppressed the expression of the above proteins.

Conclusion: Our study revealed that VCR could promote the differentiation of fibroblasts into myofibroblasts by regulating the MAPK signal pathway, which may be a promising way to treat VCR-induced PF.

Adiponectin inhibits the activation of lung fibroblasts and pulmonary fibrosis by regulating the nuclear factor kappa B (NF-κB) pathway

Idiopathic pulmonary fibrosis (IPF) is a common pulmonary interstitial disease with a high mortality rate. Adiponectin (APN) is reportedly an effective therapy for fibrosis-related diseases. This study aimed to investigate the potential effects of APN on IPF. Male BALB/c mice were injected with bleomycin (BLM) and treated with different doses of APN (0.1, 0.25, and 0.5 mg/kg). The body weights of the mice were recorded. Immunohistochemical, hematoxylin and eosin, and Masson staining were performed to evaluate pulmonary histopathological changes. Enzyme-linked immunosorbent assay (ELISA) and western blotting were performed to assess tissue inflammation. The human lung fibroblasts HELF were stimulated with TGF-β1 and treated with different doses of APN (2.5, 5, and 10 μg/ml). Cell proliferation, inflammation, and fibrosis were determined by MTT assay, EdU assay, colony formation assay, ELISA, and western blotting. APN significantly attenuated BLM-induced body weight loss, alveolar destruction, and collagen fiber accumulation in mice (p < 0.05). APN decreased the expression of α-SMA and collagen I and reduced the concentration of TNF-α, IL-6, IL-1β, and IL-18 in lung tissues (p < 0.05). In TGF-β1-treated HELF cells, cell proliferation and colony formation were inhibited by APN (p < 0.05). Additionally, the expression of α-SMA, collagen I, and pro-inflammatory cytokines were suppressed by APN (p < 0.05). APN inhibited the phosphorylation of IκB and nuclear translocation of p65. In conclusion, these findings suggest that APN is an effective agent for controlling IPF progression. The antifibrotic effects of APN might be mediated via inhibiting the NF-κB signaling pathway.

miRNAs Contained in Extracellular Vesicles Cargo Contribute to the Progression of Idiopathic Pulmonary Fibrosis: An In Vitro Aproach

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive lung disease. Lesions in the lung epithelium cause alterations in the microenvironment that promote fibroblast accumulation. Extracellular vesicles (EVs) transport proteins, lipids, and nucleic acids, such as microRNAs (miRNAs). The aim of this study was to characterize the differentially expressed miRNAs in the cargo of EVs obtained from the LL97 and LL29 fibroblast cell lines isolated from IPF lungs versus those derived from the CCD19 fibroblast cell line isolated from a healthy donors. We characterized EVs by ultracentrifugation, Western blotting, and dynamic light scattering. We identified miRNAs by small RNA-seq, a total of 1144 miRNAs, of which 1027 were known miRNAs; interestingly, 117 miRNAs were novel. Differential expression analysis showed that 77 miRNAs were upregulated and 68 were downregulated. In addition, pathway enrichment analyses from the Gene Ontology and Kyoto Encyclopedia of Genomes identified several miRNA target genes in the categories, cell proliferation, regulation of apoptosis, pathways in cancer, and proteoglycans in cancer. Our data reveal that miRNAs contained in EVs cargo could be helpful as biomarkers for fibrogenesis, diagnosis, and therapeutic intervention of IPF.

Therapeutic effects of eperisone on pulmonary fibrosis via preferential suppression of fibroblast activity

Although the exact pathogenesis of idiopathic pulmonary fibrosis (IPF) is still unknown, the transdifferentiation of fibroblasts into myofibroblasts and the production of extracellular matrix components such as collagen, triggered by alveolar epithelial cell injury, are important mechanisms of IPF development. In the lungs of IPF patients, apoptosis is less likely to be induced in fibroblasts than in alveolar epithelial cells, and this process is involved in the pathogenesis of IPF. We used a library containing approved drugs to screen for drugs that preferentially reduce cell viability in LL29 cells (lung fibroblasts from an IPF patient) compared with A549 cells (human alveolar epithelial cell line). After screening, we selected eperisone, a central muscle relaxant used in clinical practice. Eperisone showed little toxicity in A549 cells and preferentially reduced the percentage of viable LL29 cells, while pirfenidone and nintedanib did not have this effect. Eperisone also significantly inhibited transforming growth factor-β1-dependent transdifferentiation of LL29 cells into myofibroblasts. In an in vivo study using ICR mice, eperisone inhibited bleomycin (BLM)-induced pulmonary fibrosis, respiratory dysfunction, and fibroblast activation. In contrast, pirfenidone and nintedanib were less effective than eperisone in inhibiting BLM-induced pulmonary fibrosis under this experimental condition. Finally, we showed that eperisone did not induce adverse effects in the liver and gastrointestinal tract in the BLM-induced pulmonary fibrosis model. Considering these results, we propose that eperisone may be safer and more therapeutically beneficial for IPF patients than current therapies.

Integrated single-cell transcriptome analysis reveals heterogeneity of esophageal squamous cell carcinoma microenvironment

The tumor microenvironment is a highly complex ecosystem of diverse cell types, which shape cancer biology and impact the responsiveness to therapy. Here, we analyze the microenvironment of esophageal squamous cell carcinoma (ESCC) using single-cell transcriptome sequencing in 62,161 cells from blood, adjacent nonmalignant and matched tumor samples from 11 ESCC patients. We uncover heterogeneity in most cell types of the ESCC stroma, particularly in the fibroblast and immune cell compartments. We identify a tumor-specific subset of CST1⁺ myofibroblasts with prognostic values and potential biological significance. CST1⁺ myofibroblasts are also highly tumor-specific in other cancer types. Additionally, a subset of antigen-presenting fibroblasts is revealed and validated. Analyses of myeloid and T lymphoid lineages highlight the immunosuppressive nature of the ESCC microenvironment, and identify cancer-specific expression of immune checkpoint inhibitors. This work establishes a rich resource of stromal cell types of the ESCC microenvironment for further understanding of ESCC biology.

Extracellular Vesicles in Pulmonary Fibrosis Models and Biological Fluids of Interstitial Lung Disease Patients: A Scoping Review

INTRODUCTION

Interstitial lung diseases (ILDs) are a heterogeneous group of diffuse parenchymal lung disorders characterized by the pathogenetic involvement of interstitium. Therefore, an elucidation of the etiology and pathogenesis as well as the identification of diagnostic and prognostic biomarkers of such diseases is more compelling than ever. It is of note that there is increasing evidence of the involvement of extracellular vesicles (EVs) in the pathogenesis of lung diseases including lung cancer, chronic obstructive pulmonary disease and pulmonary fibrosis. It has been speculated that EVs play a pivotal role as mediators of intercellular communication, as well as the highlighting of the role of EVs as co-operators in the development of lung diseases such as IPF.

METHODS

The present study aimed to carry out a systematic exploratory search of the literature (through the scoping review approach) to identify and systematize the main results of the pathogenetic role of EVs in pulmonary fibrosis models and biological fluids from ILD patients, including plasma, bronchoalveolar lavage (BAL) and sputum.

CONCLUSION

Fibroblast-to-mesenchymal differentiation, collagen and extracellular matrix deposition are key mechanisms in the development and progression of IPF. EV-coupled miRNA are important modulators of biological processes in terms of intercellular communication as shown in pulmonary fibrosis models as well as biofluids. The helpfulness of EVs as diagnostic and theranostic markers is worth further investigation. The evolving potential of EVs to translate effective EV-based therapies into clinical practice is of growing interest, due to the urgent need for novel therapeutic strategies for IPF patients.

N6-methyladenosine modification of CDH1 mRNA promotes PM2.5-induced pulmonary fibrosis via mediating epithelial mesenchymal transition

The association between ambient airborne fine particulate matter (PM2.5) exposure and respiratory diseases has been investigated in epidemiological studies. To explore the potential mechanism of PM2.5-induced pulmonary fibrosis, sixty mice were divided into 3 groups to expose to different levels of PM2.5 for 8 and 16 weeks: filtered air (FA), unfiltered air (UA) and concentrated PM2.5 air (CA), respectively. BEAS-2B cells were treated with 0, 25, 50 and 100 μg/ml PM2.5 for 24 h. The biomarkers of pulmonary fibrosis, epithelial-mesenchymal transition (EMT), N6-methyladenosine (m6A) modification and metabolism of mRNAs were detected to characterize the effect of PM2.5 exposure. The results illustrated that PM2.5 exposure induced pathological alteration and pulmonary fibrosis in mice. The expression of E-cadherin (E-cad) was decreased whereas vimentin and N-cadherin (N-cad) expression were increased in a dose- and time-dependent manner after PM2.5 exposure. Mechanistically, PM2.5 exposure increased the levels of METTL3-mediated m6A modification of CDH1 mRNA. As a target gene of miR-494-3p, YTHDF2 was up-regulated by miR-494-3p down-regulation and then recognized m6A-modified CDH1 mRNA to inhibit the E-cad expression, consequently induced the EMT progression after PM2.5 exposure. Our study indicated that PM2.5 exposure triggered EMT progression to promote the pulmonary fibrosis via miR-494-3p/YTHDF2 recognized and METTL3 mediated m6A modification.

Activated AMPK by metformin protects against fibroblast proliferation during pulmonary fibrosis by suppressing FOXM1

Pulmonary fibrosis (PF) is a progressive and devastating lung disease of unknown etiology, excessive fibroblast proliferation serves as a key event to promote PF. Transcription factor forkhead box M1 (FOXM1) is not only a well-known proto-oncogene, but also an essential driver of cell proliferation. Recently, 5'-AMP-activated protein kinase (AMPK) is reported to reduce the incidence of PF. However, it remains elusive whether have an underlying relationship between AMPK and FOXM1 in fibroblast proliferation-mediated PF. Here, the progression of lung fibroblast proliferation and the expression levels of AMPK and FOXM1 were observed by intratracheally instilled of bleomycin (BLM) and intraperitoneal injection of metformin in C57BL/6 J mice. Meanwhile, human fetal lung fibroblast1 (HFL1) cells were respectively treated with AMPK activator metformin or AMPK inhibitor Compound C, or FOXM1 depletion by transfected small interfering RNA (siRNA) to unveil roles of AMPK, FOXM1 and the link between them on platelet-derived growth factor (PDGF)-induced fibroblast proliferation. Our results demonstrated that AMPK activated by metformin could down-regulate FOXM1 and alleviate BLM-induced mouse PF model. In vitro, activation of AMPK attenuated PDGF-induced fibroblast proliferation accompanied by the down-regulation of FOXM1. In contrast, inhibition of AMPK enhanced PDGF-induced fibroblast proliferation along with activating FOXM1. These findings suggest that AMPK can ameliorate the progression of fibroblast proliferation during PF via suppressing the expression of FOXM1 and provide new insight into seek PF treatment approaches.

Epigenetic regulation in fibrosis progress

Fibrosis, a common process of chronic inflammatory diseases, is defined as a repair response disorder when organs undergo continuous damage, ultimately leading to scar formation and functional failure. Around the world, fibrotic diseases cause high mortality, unfortunately, with limited treatment means in clinical practice. With the development and application of deep sequencing technology, comprehensively exploring the epigenetic mechanism in fibrosis has been allowed. Extensive remodeling of epigenetics controlling various cells phenotype and molecular mechanisms involved in fibrogenesis was subsequently verified. In this review, we summarize the regulatory mechanisms of DNA methylation, histone modification, noncoding RNAs (ncRNAs) and N6-methyladenosine (m6A) modification in organ fibrosis, focusing on heart, liver, lung and kidney. Additionally, we emphasize the diversity of epigenetics in the cellular and molecular mechanisms related to fibrosis. Finally, the potential and prospect of targeted therapy for fibrosis based on epigenetic is discussed.

MicroRNAs in organ fibrosis: From molecular mechanisms to potential therapeutic targets

Fibrosis is caused by chronic tissue injury and characterized by the excessive deposition of extracellular matrix (ECM) that ultimately results in organ failure and death. Owing to lacking of effective treatment against tissue fibrosis, it causes a high morbidity and mortality worldwide. Thus, it is of great importance to find an effective therapy strategy for the treatment of fibrosis. MicroRNAs (miRNAs) play vital roles in many biological processes by targeting downstream genes. Numerous studies demonstrated that miRNAs served as biomarkers of various diseases, suggesting the potential therapeutic targets for diseases. It was recently reported that miRNAs played an important role in the development of organ fibrosis, which showed a promising prospect against fibrosis by targeting intervention. Here, we summarize the roles of miRNAs in the process of organ fibrosis, including liver, lung, heart and kidney, and highlight miRNAs being novel therapeutic targets for organ fibrosis.

Long Noncoding RNA FENDRR Inhibits Lung Fibroblast Proliferation via a Reduction of β-Catenin

Idiopathic Pulmonary Fibrosis (IPF) is a chronic, progressive, and usually lethal lung disease and it has been widely accepted that fibroblast proliferation is one of the key characteristics of IPF. Long noncoding RNAs (lncRNAs) play vital roles in the pathogenesis of many diseases. In this study, we investigated the role of lncRNA FENDRR on fibroblast proliferation. Human lung fibroblasts stably overexpressing FENDRR showed a reduced cell proliferation compared to those expressing the control vector. On the other hand, FENDRR silencing increased fibroblast proliferation. FENDRR bound serine-arginine rich splicing factor 9 (SRSF9) and inhibited the phosphorylation of p70 ribosomal S6 kinase 1 (PS6K), a downstream protein of the mammalian target of rapamycin (mTOR) signaling. Silencing SRSF9 reduced fibroblast proliferation. FENDRR reduced β-catenin protein, but not mRNA levels. The reduction of β-catenin protein levels in lung fibroblasts by gene silencing or chemical inhibitor decreased fibroblast proliferation. Adenovirus-mediated FENDRR transfer to the lungs of mice reduced asbestos-induced fibrotic lesions and collagen deposition. RNA sequencing of lung tissues identified 7 cell proliferation-related genes that were up-regulated by asbestos but reversed by FENDRR. In conclusion, FENDRR inhibits fibroblast proliferation and functions as an anti-fibrotic lncRNA.

The Pathogenic Role of Smooth Muscle Cell-Derived Wnt5a in a Murine Model of Lung Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a disease characterized by extensive fibrosis of the lung tissue. Wnt5a expression was observed to be upregulated in IPF and suggested to be involved in the progression of the disease. Interestingly, smooth muscle cells (SMC) are a major source of Wnt5a in IPF patients. However, no study has been conducted until now to investigate the precise role of smooth muscle-derived Wnt5a in IPF. Here, we used the bleomycin-induced lung fibrosis model in a conditional gene-deficient mouse, where the Wnt5a gene was excised from SMC. We show here that the excision of the Wnt5a gene in SMC led to significantly improved health conditions with minimized weight loss and improved lung function. This improvement was based on a significantly lower deposition of collagen in the lung with a reduced number of fibrotic foci in lung parenchyma. Furthermore, the bleomycin-induced cellular infiltration into the airways was not altered in the gene-deficient mice compared with wild-type mice. Thus, we demonstrate that the Wnt5a expression of SMC of the airways leads to aggravated fibrosis of the lung with poor clinical conditions. This aggravation was not an influence in the bleomycin-induced inflammatory processes but on the development of fibrotic foci in lung parenchyma and the deposition of collagen.

The miR-130a-3p/TGF-βRII Axis Participates in Inhibiting the Differentiation of Fibroblasts Induced by TGF-β1

Pulmonary fibrosis (PF) is a chronic progressive interstitial lung disease that has a poor prognosis. Abnormal activation of transforming growth factor-β1 (TGF-β1) plays a crucial role in fibroblast differentiation. Mesenchymal stem cells (MSCs) are currently being considered for the treatment of PF, but the regulatory mechanisms are poorly understood. We co-cultured bone marrow-derived MSCs and mouse lung fibroblasts (MLg) in the presence of TGF-β1, and studied the protein/mRNA expression of fibrosis markers and related signaling pathways. The effects of miR-130a-3p and TGF-β receptor II (TGF-βRII) on the differentiation of MLg induced by TGF-β1 were studied using immunofluorescence assay, Western blot, and quantitative real-time PCR techniques, respectively. Our results showed that MSCs reversed the overexpression of fibrosis markers and TGF-β1/Smad signaling pathway proteins and mRNAs after TGF-β1 treatment and increased the level of miR-130a-3p. TGF-βRII was identified as a target of miR-130a-3p and was evaluated by dual-luciferase reporter assay. The miR-130a-3p/TGF-βRII axis could suppress the differentiation of lung fibroblasts via the TGF-β1/Smad signaling pathway, thereby reducing the process of PF.

MicroRNAs in Transforming Growth Factor-Beta Signaling Pathway Associated With Fibrosis Involving Different Systems of the Human Body

Fibrosis, a major cause of morbidity and mortality, is a histopathological manifestation of many chronic inflammatory diseases affecting different systems of the human body. Two types of transforming growth factor beta (TGF-β) signaling pathways regulate fibrosis: the canonical TGF-β signaling pathway, represented by SMAD-2 and SMAD-3, and the noncanonical pathway, which functions without SMAD-2/3 participation and currently includes TGF-β/mitogen-activated protein kinases, TGF-β/SMAD-1/5, TGF-β/phosphatidylinositol-3-kinase/Akt, TGF-β/Janus kinase/signal transducer and activator of transcription protein-3, and TGF-β/rho-associated coiled-coil containing kinase signaling pathways. MicroRNA (miRNA), a type of non-coding single-stranded small RNA, comprises approximately 22 nucleotides encoded by endogenous genes, which can regulate physiological and pathological processes in fibrotic diseases, particularly affecting organs such as the liver, the kidney, the lungs, and the heart. The aim of this review is to introduce the characteristics of the canonical and non-canonical TGF-β signaling pathways and to classify miRNAs with regulatory effects on these two pathways based on the influenced organ. Further, we aim to summarize the limitations of the current research of the mechanisms of fibrosis, provide insights into possible future research directions, and propose therapeutic options for fibrosis.

Emerging drug delivery strategies for idiopathic pulmonary fibrosis treatment

Idiopathic pulmonary fibrosis (IPF) is a debilitating and fatal condition that causes severe scarring of the lungs. While the pathogenesis of IPF continues to be extensively studied and several factors have been considered, an exact cause has yet to be established. With inadequate treatment options and no cure available, overall disease prognosis is still poor. Existing oral therapies, pirfenidone and nintedanib, may attempt to improve the patients' quality of life by mitigating symptoms and slowing disease progression, however chronic doses and systemic deliveries of these drugs can lead to severe side effects. The lack of effective treatment options calls for further investigation of restorative as well as additional palliative therapies for IPF. Nanoparticle-based sustained drug delivery strategies can be utilized to ensure targeted delivery for site-specific treatment as well as long-acting therapy, improving overall patient compliance. This review provides an update on promising strategies for the delivery of anti-fibrotic agents, along with an overview of key therapeutic targets as well as relevant emerging therapies currently being evaluated for IPF treatment.

Association of MALAT1 and PVT1 Variants, Expression Profiles and Target miRNA-101 and miRNA-186 with Colorectal Cancer: Correlation with Epithelial-Mesenchymal Transition

The influence of PVT1 and MALAT1 variants on colorectal cancer (CRC) susceptibility and their impact on PVT1/miRNA-186/epithelial-mesenchymal transition (EMT) and MALAT1/miRNA-101/EMT axes in CRC are unknown. We investigated the influence of PVT1 rs13255292 and MALAT1 rs3200401 on the risk of CRC and adenomatous polyps (AP), their impact on the long noncoding RNAs PVT1 and MALAT1 expression and their target miRNA-186, miRNA-101/E-cadherin pathways, along with their potential as early CRC biomarkers. Overall, 280 individuals were recruited: 140 patients with CRC, 40 patients with AP, and 100 healthy volunteers. Genotyping and serum expression profiles were assessed using qPCR. The EMT biomarker, E-cadherin, was measured by ELISA. rs3200401 was associated with increased CRC risk, whereas rs13255292 was protective. Serum PVT1 and MALAT1 were upregulated in CRC and AP patients versus healthy controls, whereas, miRNA-186, miRNA-101 and E-cadherin were downregulated in CRC versus non-CRC groups. MALAT1 showed superior diagnostic potential for CRC and predicted CRC risk among non-CRC groups in the multivariate logistic analysis. PVT1, MALAT1, miRNA-186 and miRNA-101 levels were correlated with E-cadherin, tumor stage, lymph node and distant metastasis. E-cadherin was lost in metastatic vs. non-metastatic CRC. rs3200401CC genotype carriers showed higher E-cadherin levels than CC + CT carriers. rs3200401 was correlated with lymph node status. For the first time, rs13255292 and rs3200401 are potential genetic CRC predisposition markers, with rs3200401 possibly impacting the EMT process. Serum PVT1, MALAT1, miRNA-186 and miRNA-101 are novel non-invasive diagnostic biomarkers that could improve the clinical outcome of CRC.

MicroRNA‑101 inhibits renal tubular epithelial‑to‑mesenchymal transition by targeting TGF‑β1 type I receptor

MicroRNAs (miRNAs/miRs) are key regulators of renal interstitial fibrosis (RIF). The present study was designed to identify miRNAs associated with the development of RIF, and to explore the ability of these identified miRNAs to modulate the renal tubular epithelial‑to‑mesenchymal transition (EMT) process. To this end, miRNAs that were differentially expressed between normal and fibrotic kidneys in a rat model of mercury chloride (HgCl₂)‑induced RIF were detected via an array‑based approach. Bioinformatics analyses revealed that miR‑101 was the miRNA that was most significantly downregulated in the fibrotic renal tissue samples, and this was confirmed by RT‑qPCR, which also demonstrated that this miRNA was downregulated in transforming growth factor (TGF)‑β1‑treated human proximal tubular epithelial (HK‑2) cells. When miR‑101 was overexpressed, this was sufficient to reverse TGF‑β1‑induced EMT in HK‑2 cells, leading to the upregulation of the epithelial marker, E‑cadherin, and the downregulation of the mesenchymal marker, α‑smooth muscle actin. By contrast, the downregulation of miR‑101 using an inhibitor exerted the opposite effect. The overexpression of miR‑101 also suppressed the expression of the miR‑101 target gene, TGF‑β1 type I receptor (TβR‑I), and thereby impaired TGF‑β1/Smad3 signaling, while the opposite was observed upon miR‑101 inhibition. To further confirm the ability of miR‑101 to modulate EMT, the HK‑2 cells were treated with the TβR‑I inhibitor, SB‑431542, which significantly suppressed TGF‑β1‑induced EMT in these cells. Notably, miR‑101 inhibition exerted a less pronounced effect upon EMT‑related phenotypes in these TβR‑I inhibitor‑treated HK‑2 cells, supporting a model wherein miR‑101 inhibits TGF‑β1‑induced EMT by suppressing TβR‑I expression. On the whole, the present study demonstrates that miR‑101 is capable of inhibiting TGF‑β1‑induced tubular EMT by targeting TβR‑I, suggesting that it may be an important regulator of RIF.

MiRNA, a New Treatment Strategy for Pulmonary Fibrosis

Pulmonary fibrosis (PF) is the most common chronic, progressive interstitial lung disease, mainly occurring in the elderly, with a median survival of 2-4 years after diagnosis. Its high mortality rate attributes to the delay in diagnosis due to its generic symptoms, and more importantly, to the lack of effective treatments. MicroRNAs (miRNAs) are a class of small non-coding RNAs that are involved in many essential cellular processes, including extracellular matrix remodeling, alveolar epithelial cell apoptosis, epithelial-mesenchymal transition, etc. We summarized the dysregulated miRNAs in TGF-β signaling pathway-mediated PF in recent years with dual effects, such as anti-fibrotic let-7 family and pro-fibrotic miR-21 members. Therefore, this review will set out the latest application of miRNAs to provide a new direction for PF treatment.

miR‑320a‑3P alleviates the epithelial‑mesenchymal transition of A549 cells by activation of STAT3/SMAD3 signaling in a pulmonary fibrosis model

Pulmonary fibrosis (PF) is a common, chronic and incurable lung disease, in which the lungs become scarred over time. MicroRNAs (miRNAs/miRs) serve key roles in various biological processes, including cell proliferation, differentiation, apoptosis and the regulation of epithelial-mesenchymal transition (EMT) process. The aim of the present study was to investigate the underlying mechanism of miR-320a-3p as a potential therapeutic target for PF. Clinical samples and microarray datasets collected from various databases were used to evaluate the expression of miR-320a-3p in PF. A549 cells were used to construct an EMT model of PF. A dual-luciferase reporter assay system was used to identify target genes of miR-320a-3p. Western blot analysis and immunofluorescence staining were used to determine the roles of miR-320a-3p and its target genes in the EMT process in PF. The present study found that, compared with lung tissue of healthy control subjects, the expression of miR-320a-3p in lung tissue of PF patients was significantly reduced. The expression levels of miR-320a-3p decreased in TGF-β1-stimulated A549 cells in a time- and concentration-dependent manner. The overexpression of miR-320a-3p suppressed EMT markers induced by TGF-β1 in A549 cells and STAT3 was identified as a potential target gene of miR-320a-3p. Furthermore, the expression changes of miR-320a-3p and STAT3 were found to significantly affect the expression of phosphorylated SMAD3 in TGF-β1-stimulated A549 cells. Briefly, overexpression of miR-320a-3p could inhibit the EMT process in PF by downregulating STAT3 expression. The mechanism mediating these effects may partly involve crosstalk between the SMAD3 and STAT3.

Silencing of long noncoding RNA H19 alleviates pulmonary injury, inflammation, and fibrosis of acute respiratory distress syndrome through regulating the microRNA-423-5p/FOXA1 axis

PURPOSE

This study aimed to explore the regulatory effects and mechanisms of long noncoding RNA H19 (H19) on pulmonary injury, inflammation, and fibrosis of acute respiratory distress syndrome (ARDS).

MATERIALS AND METHODS

A rat model of ARDS was established by intratracheal instillation of 2 mg/kg lipopolysaccharide (LPS). qRT-PCR was performed to detect the expression of H19, miR-423-5p, tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, IL-6, monocyte chemoattractant protein (MCP)-1, and vascular endothelial growth factor (VEGF). Histology score was assessed by hematoxylin-eosin (HE) staining. Enzyme-linked immunosorbent assay (ELISA) was used to detect the levels of proinflammatory cytokines and the content of VEGF in bronchoalveolar lavage fluid (BALF). The lung fibrosis was evaluated using western blot and Masson's trichrome staining. Dual-luciferase reporter gene assay was used for confirming the relationship between miR-423-5p and H19/FOXA1 in alveolar macrophage cells (MH-S) and alveolar epithelial cells (MLE-12). The regulatory effects of H19/miR-423-5p/FOXA1 axis on the inflammation and fibrosis were further analyzed in LPS-induced MH-S cells.

RESULTS

The expression of H19 and FOXA1 was significantly up-regulated, while the expression of miR-423-5p was down-regulated in LPS-induced ARDS rats. Silencing of H19 decreased the mRNA expression of TNF-α, IL-1β, IL-6, MCP-1, and VEGF, the contents of TNF-α, IL-1β, IL-6, and VEGF in BALF, and histology score in LPS-induced ARDS rats. H19 knockdown also reduced the fibrosis scores and the protein expression of vimentin and α-SMA, and elevated the protein expression of E-cadherin in LPS-induced ARDS rats. Furthermore, silencing of miR-423-5p and overexpression of FOXA1 reversed the inhibitory effects of si-H19 on the inflammation and fibrosis of LPS-induced MH-S cells.

CONCLUSIONS

Silencing of H19 relieved the pulmonary injury, inflammation and fibrosis of LPS-induced ARDS in rats. Silencing of H19 also alleviated the inflammation and fibrosis of LPS-induced MH-S cells through regulating the miR-423-5p/FOXA1 axis.

Ticagrelor Ameliorates Bleomycin-Induced Pulmonary Fibrosis in Rats by Inhibition of TGF-β1/Smad3 and PI3K/AKT/mTOR Pathways

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a serious disease with high mortality rate. Activation of transforming growth factor (TGF)-β1 production and signalling is considered the corner stone in the epithelial-mesenchymal transition (EMT) process. EMT plays a central role in development of fibrosis in many organs including the lungs. Activated platelets are an important source of TGF-β1 and play a pivotal role in EMT and fibrosis process. The antiplatelet, ticagrelor was previously found to inhibit the EMT in different types of cancer cells, but its ability to serve as an anti-pulmonary fibrosis (PF) agent was not previously investigated.

OBJECTIVE

In this study, we aim to investigate the potential ability of ticagrelor to ameliorate bleomycin-induced fibrosis in rats.

METHODS

PF was induced in rats by intratracheal BLM at a dose of 3 mg/kg. The effect of daily daily 20 mg/kg oral ticagrelor on different histological and biochemical parameters of fibrosis was investigated.

RESULTS

Our results revealed that ticagrelor can alleviate lung fibrosis. We found that ticagrelor inhibited TGF-β1 production and suppressed Smad3 activation and signaling pathway with subsequent inhibition of Slug and Snail. In addition, ticagrelor antagonized PI3K/AKT/mTOR pathway signaling. Moreover, ticagrelor inhibited the EMT that revealed by its ability to up-regulate the epithelial markers as E-cadherin (E-cad) and to decrease the expression of the mesenchymal markers as vimentin (VIM) and alpha-smooth muscle actin (α-SMA).

CONCLUSION

Our results suggest that the P2Y12 inhibitor, ticagrelor may have a therapeutic potential in reducing the progression of PF.

microRNA-186 in extracellular vesicles from bone marrow mesenchymal stem cells alleviates idiopathic pulmonary fibrosis via interaction with SOX4 and DKK1

Background

Previous reports have identified that human bone marrow mesenchymal stem cell-derived extracellular vesicles (BMSC-EVs) with their cargo microRNAs (miRNAs) are a promising therapeutic approach for the treatment of idiopathic pulmonary fibrosis (IPF). Therefore, we explored whether delivery of microRNA-186 (miR-186), a downregulated miRNA in IPF, by BMSC EVs could interfere with the progression of IPF in a murine model.

Methods

In a co-culture system, we assessed whether BMSC-EVs modulated the activation of fibroblasts. We established a mouse model of PF to evaluate the in vivo therapeutic effects of BMSC-EVs and determined miR-186 expression in BMSC-EVs by polymerase chain reaction. Using a loss-of-function approach, we examined how miR-186 delivered by BMSC-EVs affected fibroblasts. The putative relationship between miR-186 and SRY-related HMG box transcription factor 4 (SOX4) was tested using luciferase assay. Next, we investigated whether EV-miR-186 affected fibroblast activation and PF by targeting SOX4 and its downstream gene, Dickkopf-1 (DKK1).

Results

BMSC-EVs suppressed lung fibroblast activation and delayed IPF progression in mice. miR-186 was downregulated in IPF but enriched in the BMSC-EVs. miR-186 delivered by BMSC-EVs could suppress fibroblast activation. Furthermore, miR-186 reduced the expression of SOX4, a target gene of miR-186, and hence suppressed the expression of DKK1. Finally, EV-delivered miR-186 impaired fibroblast activation and alleviated PF via downregulation of SOX4 and DKK1.

Conclusion

In conclusion, miR-186 delivered by BMSC-EVs suppressed SOX4 and DKK1 expression, thereby blocking fibroblast activation and ameliorating IPF, thus presenting a novel therapeutic target for IPF.

The MIR155 host gene/microRNA-627/HMGB1/NF-κB loop modulates fibroblast proliferation and extracellular matrix deposition

Pulmonary fibrosis (PF), which is characterized by excessive matrix formation, may ultimately lead to irreversible lung damage and thus death. Fibroblast activation has been regarded as a central event during PF pathogenesis. In our previous study, we confirmed that the miR-627/high-mobility group box protein 1 (HMGB1)/Nuclear factor kappa beta (NF-κB) axis modulates transforming growth factor beta 1 (TGFβ1)-induced pulmonary fibrosis. In the present study, we investigated the upstream factors leading to miR-627 dysregulation in the process of pulmonary fibroblast activation and PF. The lncRNA MIR155 host gene (MIR155HG) was found to be abnormally upregulated in pulmonary fibrosis tissues and TGFβ1-stimulated normal human primary lung fibroblasts (NHLFs). By directly binding to miR-627, MIR155HG inhibited miR-627 expression. MIR155HG overexpression enhanced TGFβ1-induced increases in HMGB1 protein expression and p65 phosphorylation, NHLF proliferation, and extracellular matrix (ECM) deposition. In contrast, miR-627 overexpression attenuated the TGFβ1-induced changes in NHLFs and significantly reversed the effects of MIR155HG overexpression. Under TGFβ1 stimulation, miR-627 inhibition promoted, whereas JSH-23 treatment inhibited NF-κB activation; in NHLFs, NF-κB overexpression upregulated, whereas JSH-23 treatment downregulated MIR155HG expression. In tissue samples, HMGB1 protein levels and p65 phosphorylation were increased; MIR155HG was negatively correlated with miR-627 and positively correlated with HMGB1. In conclusion, we validated that the MIR155HG/miR-627/HMGB1/NF-κB axis formed a regulatory loop that modulates TGFβ1-induced NHLF activation. Considering the critical role of NHLF activation in PF pathogenesis, the NF-κB/MIR155HG/miR-627/HMGB1 regulatory loop could exert a vital effect on PF pathogenesis. Further in vivo and clinical investigations are required to confirm this model.

MicroRNA-206 inhibits influenza A virus replication by targeting tankyrase 2

Due to the frequent mutations, influenza A virus (IAV) becomes resistant to anti-viral drugs targeting influenza viral proteins. There are increasing interests in anti-viral agents that target host cellular proteins required for virus replication. Tankyrase (TNKS) has poly (ADP-ribose) polymerase activity and is a negative regulator of many host proteins. The objectives of this study are to study the role of TNKS2 in IAV infection, identify the microRNAs targeting TNKS2, and to understand the mechanisms involved. We found that TNKS2 expression was elevated in human lung epithelial cells and mouse lungs during IAV infection. Knock-down of TNKS2 by RNA interference reduced viral replication. Using a computation approach and 3'-untranslation regions (3'-UTR) reporter assay, we identified miR-206 as the microRNA that targeted TNKS2. Overexpression of miR-206 reduced viral protein levels and virus production in cell culture. The effect of miR-206 on IAV replication was strain-independent. miR-206 activated JNK/c-Jun signalling, induced type I interferon expression and enhanced Stat signalling. Finally, the delivery of an adenovirus expressing miR-206 into the lung of mice challenged with IAV increased type I interferon response, suppressed viral load in the lungs and increased survival. Our results indicate that miR-206 has anti-influenza activity by targeting TNKS2 and subsequently activating the anti-viral state.