miR-30a as Potential Therapeutics by Targeting TET1 through Regulation of Drp-1 Promoter Hydroxymethylation in Idiopathic Pulmonary 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.

miR-141-3p attenuates inflammation and oxidative stress-induced pulmonary fibrosis in ARDS via the Keap1/Nrf2/ARE signaling pathway

The present research aimed to investigate the effects and mechanisms of microRNA (miR)-141-3p on pulmonary fibrosis of acute respiratory distress syndrome (ARDS). A rat ARDS model was established by the intratracheal drip of 10 mg/kg lipopolysaccharide (LPS). miR-141-3p and Kelch-like ECH-associated protein 1 (Keap1) expression was detected using RT-qPCR assay. Inflammatory factors in bronchoalveolar lavage fluid (BALF) and lung tissues were measured with enzyme-linked immunosorbent assay (ELISA). Lung fibrosis was evaluated using Masson's trichrome staining and hydroxyproline assay kits. Tissue oxidative stress marker levels were assessed by a commercial kit. Protein variations in the EMT pathway and Keap1/nuclear factor-erythroid 2-related factor 2 (Nrf2)/antioxidant response element (ARE) pathway were investigated by Western blot analysis. Targeting relationship verified by dual-luciferase reporter assay. The expression of miR-141-3p was significantly upregulated in LPS-induced ARDS rats, while Keap1 was downregulated. Overexpression of miR-141-3p decreased the levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, superoxide dismutase (SOD), and glutathione (GSH) while elevating malondialdehyde (MDA) expression in LPS-induced ARDS rats. Elevation of miR-141-3p reduced fibrosis scores, enhanced E-cadherin protein expression, and decreased vimentin and α-SMA protein expression in LPS-induced ARDS rats. This elevation of miR-141-3p also upregulated Nrf2, heme oxygenase-1 (HO-1), and NAD(P)H:quinone oxido-reductase-1 (NQO1) proteins levels. Moreover, Keap1 overexpression reversed the inhibitory effects of miR-141-3p on LPS-triggered inflammation, oxidative stress, and fibrosis. miR-141-3p may attenuate inflammation and oxidative stress-induced pulmonary fibrosis in ARDS via the Keap1/Nrf2/ARE signaling pathway. Our study provides new ideas for the treatment of ARDS.

The interactions of subcellular organelles in pulmonary fibrosis induced by carbon black nanoparticles: a comprehensive review

Owing to the widespread use and improper emissions of carbon black nanoparticles (CBNPs), the adverse effects of CBNPs on human health have attracted much attention. In toxicological research, carbon black is frequently utilized as a negative control because of its low toxicity and poor solubility. However, recent studies have indicated that inhalation exposure to CBNPs could be a risk factor for severe and prolonged pulmonary inflammation and fibrosis. At present, the pathogenesis of pulmonary fibrosis induced by CBNPs is still not fully elucidated, but it is known that with small particle size and large surface area, CBNPs are more easily ingested by cells, leading to organelle damage and abnormal interactions between organelles. Damaged organelle and abnormal organelles interactions lead to cell structure and function disorders, which is one of the important factors in the development and occurrence of various diseases, including pulmonary fibrosis. This review offers a comprehensive analysis of organelle structure, function, and interaction mechanisms, while also summarizing the research advancements in organelles and organelle interactions in CBNPs-induced pulmonary fibrosis.

Identification of idiopathic pulmonary fibrosis hub genes and exploration of the mechanisms of action of Jinshui Huanxian formula

Idiopathic pulmonary fibrosis (IPF) is a common and heterogeneous chronic disease, and the mechanism of Jinshui Huanxian formula (JHF) on IPF remains unclear. For a total of 385 lung normal tissue samples from the Gene Expression Omnibus database, 37,777,639 gene pairs were identified through microarray and RNA-seq platforms. Using the individualized differentially expressed gene (DEG) analysis algorithm RankComp (FDR < 0.01), we identified 344 genes as DEGs in at least 95 % (n = 81) of the IPF samples. Of these genes, IGF1, IFNGR1, GLI2, HMGCR, DNM1, KIF4A, and TNFRSF11A were identified as hub genes. These genes were verified using quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) in mice with pulmonary fibrosis (PF) and MRC-5 cells, and they were highly effective at classifying IPF samples in the independent dataset GSE134692 (AUC = 0.587-0.788) and mice with PF (AUC = 0.806-1.000). Moreover, JHF ameliorated the pathological changes in mice with PF and significantly reversed the changes in hub gene expression (KIF4A, IFNGR1, and HMGCR). In conclusion, a series of IPF hub genes was identified, and validated in an independent dataset, mice with PF, and MRC-5 cells. Moreover, the abnormal gene expression was normalized by JHF. These findings provide guidance for further exploration of the pathogenesis and treatment of IPF.

Epigenetic hallmarks in pulmonary fibrosis: New advances and perspectives

Epigenetics indicates that certain phenotypes of an organism can undergo heritable changes in the absence of changes in the genetic DNA sequence. Many studies have shown that epigenetic patterns play an important role in the lung and lung diseases. Pulmonary fibrosis (PF) is also a type of lung disease. PF is an end-stage change of a large group of lung diseases, characterized by fibroblast proliferation and massive accumulation of extracellular matrix, accompanied by inflammatory injury and histological destruction, that is, structural abnormalities caused by abnormal repair of normal alveolar tissue. It causes loss of lung function in patients with multiple complex diseases, leading to respiratory failure and subsequent death. However, current treatment options for IPF are very limited and no drugs have been shown to significantly prolong the survival of patients. Therefore, based on a systematic understanding of the disease mechanisms of PF, this review integrates the role of epigenetics in the development and course of PF, describes preventive and potential therapeutic targets for PF, and provides a theoretical basis for further exploration of the mechanisms of PF.

MiR-30a inhibits silica dust-induced epithelial-mesenchymal transition by targeting Snail

The mechanism of action of MicroRNA-30a(miR-30a) and Snail, a transcription factor, in silica(SiO2) dust-induced pulmonary EMT and secondary pulmonary fibrosis remains elusive. In this study, the cellular EMT model induced by the stimulation of A549 cells with SiO2 was established. A549 cells were transfected with miR-30a mimic and miR-30a inhibitor and the SNAIL gene was silenced to examine the mechanism of miR-30a targeting Snail to regulate silica dust-induced EMT. The results showed that 50 μg/mL SiO2 stained A549 cells for 24 h could induce EMT in A549 cells. Exposure of A549 cells to SiO2 dust decreased miR-30a expression, as well as mRNA and protein expression levels of E-cad. Conversely, SiO2 exposure increased mRNA and protein expression levels of α-SMA, vimentin, and Snail. The miR-30a mimic upregulated mRNA and protein expression levels of E-cadherin in SiO2-induced A549 cells, while downregulating mRNA and protein expression levels of α-SMA, vimentin and Snail. MiR-30a inhibitors have the opposite effect. Silencing the SNAIL gene, followed by SiO2 dust-induced stimulation of A549 cells, could enhance mRNA and protein expression levels of E-cad, whereas those of α-SMA and vimentin were reduced. Altogether, we found that miR-30a directly targeted Snail and inhibited its expression, thereby delaying silica induced pulmonary EMT.

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.

A Proof-of-Concept Analysis of Plasma-Derived Exosomal microRNAs in Interstitial Pulmonary Fibrosis Secondary to Antisynthetase Syndrome

Antisynthetase syndrome (ASSD) is an autoimmune disease characterized by the positivity of autoantibodies against different aminoacyl transfer RNA (tRNA) synthetases. Morbidity and mortality of this disease are highly affected by interstitial lung disease (ILD) which is present in about 80% of patients. In this study, we investigated possible differences in 84 immune-related circulating miRNAs between ASSD patients with and without ILD; we enrolled 15 ASSD patients, 11 with ILD (ILD+) and 4 without ILD (ILD-), and 5 patients with idiopathic pulmonary fibrosis (IPF) as an additional control group. All patients were at disease onset and not on therapy at the time of inclusion. Differentially expressed miRNAs were identified in plasma-derived exosomes, using an miRNA PCR array (MIHS-111ZG, Qiagen, Hilden, Germany); miR-30a-5p and miR-29c-3p were upregulated in ASSD-ILD patients compared to patients without lung involvement (adjusted p-value < 0.05). IPF patients showed higher miR-29c-3p expression levels with respect to both ASSD and ASSD-ILD (p = 0.0005), whereas levels of miR-30a-5p were not different. miR-29c-3p and miR-30a-5p are overexpressed in ASSD-ILD+ patients compared with ILD−. These miRNAs are involved in the regulation of inflammation and fibrosis through their action on NF-κB and TGF-β1. Although the mechanistic role of these miRNAs in ASSD-ILD development has to be elucidated, we suggest that their exosome levels could be useful in identifying patients at risk of ILD.

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.

Expression of Selected microRNAs in Migraine: A New Class of Possible Biomarkers of Disease?

Preliminary but convergent findings suggest a role for microRNAs (miRNAs) in the generation and maintenance of chronic pain and migraine. Initial observations showed that serum levels of miR-382-5p and miR-34a-5p expression were increased in serum during the migraine attack, with miR-382-5p increasing in the interictal phase as well. By contrast, miR-30a-5p levels were lower in migraine patients compared to healthy controls. Of note, antimigraine treatments proved to be capable of influencing the expression of these miRNAs. Altogether, these observations suggest that miRNAs may represent migraine biomarkers, but several points are yet to be elucidated. A major concern is that these miRNAs are altered in a broad spectrum of painful and non-painful conditions, and thus it is not possible to consider them as truly “migraine-specific” biomarkers. We feel that these miRNAs may represent useful tools to uncover and define different phenotypes across the migraine spectrum with different treatment susceptibilities and clinical features, although further studies are needed to confirm our hypothesis. In this narrative review we provide an update and a critical analysis of available data on miRNAs and migraines in order to propose possible interpretations. Our main objective is to stimulate research in an area that holds promise when it comes to providing reliable biomarkers for theoretical and practical scientific advances.

miR-21 Exerts Anti-proliferative and Pro-apoptotic Effects in LPS-induced WI-38 Cells via Directly Targeting TIMP3

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease, which was caused by a complex interplay of inflammatory responses and chronic damage. miR-21 is increased in patients with IPF, but its function in the embryonic lung-derived diploid fibroblasts cells subjected to LPS is elusive. miRNA expression profile was obtained from GEO database and target genes of miRNAs were forecasted by TargetScan. To mimic the LPS-induced injury, different concentrations of LPS were applied to treat WI-38 cells. Functional in vitro experiments were conducted to examine the role of miR-21 and TIMP3. Luciferase report assay was performed to verify the relationship between miR-21 and TIMP3. qRT-PCR, western blotting, and ELISA were conducted to detect the levels of the related miRNAs, proteins, and inflammatory factors. miR-21 presented higher levels in interstitial pneumonia patients and LPS-induced WI-38 cells. Overexpression of miR-21 was negatively correlated with the proliferative capability of LPS-treated WI-38 cells. miR-21 directly targets TIMP3. TIMP3 restored the suppressive impact of miR-21 mimic on the proliferation, while TIMP3 alleviated the promoting impact of miR-21 mimic on the apoptosis of WI-38 cells treated by LPS. miR-21 inhibited Bcl-2 but increased Bax, cleaved caspase-3, and cleaved caspase-9. Besides, miR-21 elevated the levels of IL-6 and IL-β but reduced the IL-10, which were weakened by TIMP3. Totally, miR-21 aggravated the LPS-induced lung injury and modulated inflammatory responses by targeting TIMP3.

Role of Non-Coding RNAs in Post-Transcriptional Regulation of Lung Diseases

Non-coding RNAs (ncRNAs), notably microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), have recently gained increasing consideration because of their versatile role as key regulators of gene expression. They adopt diverse mechanisms to regulate transcription and translation, and thereby, the function of the protein, which is associated with several major biological processes. For example, proliferation, differentiation, apoptosis, and metabolic pathways demand fine-tuning for the precise development of a specific tissue or organ. The deregulation of ncRNA expression is concomitant with multiple diseases, including lung diseases. This review highlights recent advances in the post-transcriptional regulation of miRNAs and lncRNAs in lung diseases such as asthma, chronic obstructive pulmonary disease, cystic fibrosis, and idiopathic pulmonary fibrosis. Further, we also discuss the emerging role of ncRNAs as biomarkers as well as therapeutic targets for lung diseases. However, more investigations are required to explore miRNAs and lncRNAs interaction, and their function in the regulation of mRNA expression. Understanding these mechanisms might lead to early diagnosis and the development of novel therapeutics for lung diseases.

Evaluation of microRNA expression in a sheep model for lung fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a chronic progressive fibroproliferative disorder that has one of the poorest prognoses amongst interstitial lung diseases. Recently, the finding of aberrant expression levels of miRNAs in IPF patients has drawn significant attention to the involvement of these molecules in the pathogenesis of this disease. Clarification of the differential expression of miRNAs in health and disease may identify novel therapeutic strategies that can be employed in the future to combat IPF. This study evaluates the miRNA expression profiles in a sheep model for lung fibrosis and compares them to the miRNA profiles of both IPF patients and the mouse bleomycin model for pulmonary fibrosis. Pathway enrichment analyses were performed on differentially expressed miRNAs to illustrate which biological mechanisms were associated with lung fibrosis.

RESULTS

We discovered 49 differentially expressed miRNAs in the sheep fibrosis model, in which 32 miRNAs were significantly down regulated, while 17 miRNAs were significantly upregulated due to bleomycin-induced lung injury. Moreover, the miRNA families miR-29, miR-26, miR-30, let-7, miR-21, miR-19, miR-17 and miR-199 were aberrantly expressed in both sheep and mouse models, with similar differential miRNAs expression observed in IPF cases. Importantly, 18 miRNAs were aberrantly expressed in both the sheep model and IPF patients, but not in mice.

CONCLUSION

Together with pathway enrichment analyses, these results show that the sheep model can potentially be used to characterize previously unrecognized biological pathways associated with lung fibrosis.

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.

Exosomes derived from induced pluripotent stem cells suppresses M2-type macrophages during pulmonary fibrosis via miR-302a-3p/TET1 axis

Idiopathic pulmonary fibrosis (PF) is a type of chronic lung disease. Here, we investigated the effect of induced pluripotent stem cell (iPSC)-derived exosomes (iPSC-exosomes) on M2-type macrophages which play a critical role in pulmonary fibrosis. Exosomes were purified from the conditioned medium of iPSCs. Mice models of pulmonary fibrosis were established by intratracheal instillation with 5 mg/kg bleomycin. Thereafter, the histopathological changes and collagen deposition were detected by HE and masson staining. Meanwhile the level of M2-type macrophages was elevated by immunofluorescence staining with F4/80 and Arg-1. Luciferase reporter assay was conducted to verify the binding of miR-302a-3p to ten-eleven translocation 1 (TET1). Our results showed that, after treatment with iPSC-exosomes, the pulmonary fibrosis induced by bleomycin was relieved, with less collagen deposition. In addition, the increased M2-type macrophages in PF mice were reduced upon treatment with iPSC-exosomes. Moreover, we found that the iPSC-exosomes showed higher level of miR-302a-3p. Interestingly, the level of miR-302a-3p in the lungs of PF mice was increased upon treatment with iPSC-exosomes. Furthermore, we verified that TET1 was a direct target of miR-302a-3p. Up-regulation of miR-302a-3p or TET1 silencing repressed M2-type macrophages. Down-regulation of miR-302a-3p abolished the beneficial effects of iPSC-exosomes on pulmonary fibrosis. Collectively, our study revealed that iPSC-exosomes delivered miR-302a-3p to suppress the M2-type macrophages via targeting TET1, thus mitigating pulmonary fibrosis. This study indicates that iPSC-exosomes may become a potential therapeutic agent for pulmonary fibrosis.

The function of non-coding RNAs in idiopathic pulmonary fibrosis

Non-coding ribonucleic acids (ncRNAs) are a diverse group of RNA molecules that are mostly not translated into proteins after transcription, including long non-coding RNAs (lncRNAs) with longer than 200 nucleotides non-coding transcripts and microRNAs (miRNAs) which are only 18–22 nucleotides. As families of evolutionarily conserved ncRNAs, lncRNAs activate and repress genes via a variety of mechanisms at both transcriptional and translational levels, whereas miRNAs regulate protein-coding gene expression mainly through mRNA silencing. ncRNAs are widely involved in biological functions, such as proliferation, differentiation, migration, angiogenesis, and apoptosis. Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease with a poor prognosis. The etiology of IPF is still unclear. Increasing evidence shows the close correlations between the development of IPF and aberrant expressions of ncRNAs than thought previously. In this study, we provide an overview of ncRNAs participated in pathobiology of IPF, seeking the early diagnosis biomarker and aiming for potential therapeutic applications for IPF.

Gene therapy strategies for idiopathic pulmonary fibrosis: recent advances, current challenges, and future directions

Idiopathic pulmonary fibrosis (IPF) is a chronic disease in which the lungs become irreversibly scarred, leading to declining lung function. As currently available drugs do not cure IPF, there remains a great medical need for more effective treatments. Perhaps this need could be addressed by gene therapies, which offer powerful and versatile ways to attenuate a wide range of processes involved in fibrosis. Despite the potential benefits of gene therapy, no one has reviewed the current state of knowledge regarding its application for treating IPF. We therefore analyzed publications that reported the use of gene therapies to treat pulmonary fibrosis in animals, as clinical studies have not been published yet. In this review, we first provide an introduction on the pathophysiology of IPF and the most well-established gene therapy approaches. We then present a comprehensive evaluation of published animal studies, after which we provide recommendations for future research to address challenges with respect to the selection and use of animal models as well as the development of delivery vectors and dosage forms. Addressing these considerations will bring gene therapies one step closer to clinical testing and thus closer to patients.

In vivo therapeutic success of MicroRNA-155 antagomir in a mouse model of pulmonary fibrosis induced by bleomycin

BACKGROUND/AIMS

MicroRNAs (miRNAs) play critical regulatory roles in the pathogenesis of pulmonary fibrosis. The aim of this study was to explore whether miRNA antagomirs could serve as potential therapeutic agents in interstitial lung diseases.

METHODS

A mouse model of pulmonary fibrosis was established by intratracheal injection of bleomycin (BLM). Using microarray analysis, up-regulated miRNAs were identified during the development of pulmonary fibrosis. miR-155 was chosen as the candidate miRNA. Fifteen mice were then randomized into the following three groups: BLM + antagomiR-155 group, treated with BLM plus intravenously injected with antagomiR-155; BLM group, treated with intratracheal BLM plus phosphate-buffered saline (PBS); and a control group, treated with PBS only. Lung tissues were collected for histopathological analysis, hydroxyproline measurement, and Western blotting. Enzyme-linked immunosorbent assays were used for the measurement of cytokines associated with pulmonary fibrosis.

RESULTS

Histological changes and hydroxyproline levels induced by BLM were significantly inhibited by antagomiR-155. The levels of interleukin 4 (IL-4) and transforming growth factor-β (TGF-β) expression were increased after BLM treatment. However, miR-155 silencing decreased the expression of IL-4, TGF-β, and interferon-γ. TGF-β-activated kinase 1/mitogen-activated protein kinase kinase kinase 7 (MAP3K7)-binding protein 2 (TAB2) of the mitogen-activated protein kinase (MAPK) signaling pathway, was activated by BLM and inhibited by in vivo silencing of miR-155 via antagomiR-155.

CONCLUSION

In vivo treatment with antagomiR-155 alleviated the pathological changes induced by BLM and may be a promising therapeutic strategy for pulmonary fibrosis.

More than a Genetic Code: Epigenetics of Lung Fibrosis

At the end of the last century, genetic studies reported that genetic information is not transmitted solely by DNA, but is also transmitted by other mechanisms, named as epigenetics. The well-described epigenetic mechanisms include DNA methylation, biochemical modifications of histones, and microRNAs. The role of altered epigenetics in the biology of various fibrotic diseases is well-established, and recent advances demonstrate its importance in the pathogenesis of pulmonary fibrosis-predominantly referring to idiopathic pulmonary fibrosis, the most lethal of the interstitial lung diseases. The deficiency in effective medications suggests an urgent need to better understand the underlying pathobiology. This review summarizes the current knowledge concerning epigenetic changes in pulmonary fibrosis and associations of these changes with several cellular pathways of known significance in its pathogenesis. It also designates the most promising substances for further research that may bring us closer to new therapeutic options.

Pulmonary involvement in systemic sclerosis: exploring cellular, genetic and epigenetic mechanisms

Systemic sclerosis (SSc) is a chronic progressive autoimmune disease characterized by immune inflammation, vasculopathy, and fibrosis. There are still numerous uncertainties in the understanding of disease initiation and progression. Pulmonary involvement in SSc, and particularly pulmonary fibrosis, is critical for all organ systems affections in this disease. This review is aimed to describe and analyze new findings in the pathophysiology of SSc-associated pulmonary involvement and to explore perspective diagnostic and therapeutic strategies. A myriad of cellular interactions is explored in the dynamics of progressive interstitial lung disease (ILD) and pulmonary hypertension (PH) in SSc. The role of exosomes, microvesicles, and apoptotic bodies is examined and the impact of micro and long non-coding RNAs, DNA methylation, and histone modification in SSc is discussed.

Mitochondria dysfunction and metabolic reprogramming as drivers of idiopathic pulmonary fibrosis

Idiopathic pulmonary fibrosis (IPF) is a devastating lung disease of unknown etiology. It is characterized by deposition of extracellular matrix proteins, like collagen and fibronectin in the lung interstitium leading to respiratory failure. Our understanding of the pathobiology underlying IPF is still incomplete; however, it is accepted that aging is a major risk factor in the disease while growing evidence suggests that the mitochondria plays an important role in the initiation and progression of pulmonary fibrosis. Mitochondria dysfunction and metabolic reprogramming had been identified in different IPF lung cells (alveolar epithelial cells, fibroblasts, and macrophages) promoting low resilience and increasing susceptibility to activation of profibrotic responses. Here we summarize changes in mitochondrial numbers, biogenesis, turnover and associated metabolic adaptations that promote disrepair and fibrosis in the lung. Finally, we highlight new possible therapeutic approaches focused on ameliorate mitochondrial dysfunction.

New perspectives on the role of Drp1 isoforms in regulating mitochondrial pathophysiology

Mitochondria are dynamic organelles constantly undergoing fusion and fission. A concerted balance between the process of mitochondrial fusion and fission is required to maintain cellular health under different physiological conditions. Mutation and dysregulation of Drp1, the major driver of mitochondrial fission, has been associated with various neurological, oncological and cardiovascular disorders. Moreover, when subjected to pathological insults, mitochondria often undergo excessive fission, generating fragmented and dysfunctional mitochondria leading to cell death. Therefore, manipulating mitochondrial fission by targeting Drp1 has been an appealing therapeutic approach for cytoprotection. However, studies have been inconsistent. Studies employing Drp1 constructs representing alternate Drp1 isoforms, have demonstrated differing impacts of these isoforms on mitochondrial fission and cell death. Furthermore, there are distinct expression patterns of Drp1 isoforms in different tissues, suggesting idiosyncratic engagement in specific cellular functions. In this review, we will discuss these inherent variations among human Drp1 isoforms and how they could affect Drp1-mediated mitochondrial fission and cell death.

Decreased MiR-30a promotes TGF-β1-mediated arachnoid fibrosis in post-hemorrhagic hydrocephalus

Background

Fibrosis in the ventricular system is closely associated with post-hemorrhagic hydrocephalus (PHH). It is characterized by an expansion of the cerebral ventricles due to CSF accumulation following intraventricular hemorrhage (IVH). The activation of transforming growth factor-β1 (TGF-β1) may be involved in thrombin-induced arachnoid fibrosis.

Methods

A rat model of PHH was established by injection of autologous non-anticoagulated blood from the right femoral artery into the lateral ventricles. Differential expression of miR-30a was detected in rat arachnoid cells by RNA sequencing. AP-1, c-Fos, and TRAF3IP2 were knocked down in primary arachnoid cells, and the degree of arachnoid fibrosis was assessed.

Results

Decreased expression of miR-30a and increased expression of TRAF3IP2, TGF-β1, and α-SMA were detected in the arachnoid cells of PHH rat. Besides, overexpression of miR-30a targets TRAF3IP2 mRNA 3′UTR and inhibits the expression of TRAF3IP2, TGF-β1, and α-SMA in the primary arachnoid cells. Furthermore, TRAF3IP2 activates AP-1 to promote arachnoid fibrosis. The content of type I collagen in the primary arachnoid cells was reduced after the silencing of AP-1 and TRAF3IP2.

Conclusions

This study identified a miR-30a-regulated mechanism of arachnoid fibrosis, suggesting a previously unrecognized contribution of miR-30a to the pathogenesis of fibrosis in the ventricular system. These results might provide a new target for the clinical diagnosis and treatment of PHH.

miR-1285-3p Controls Colorectal Cancer Proliferation and Escape from Apoptosis through DAPK2

MicroRNAs are tiny but powerful regulators of gene expression at the post-transcriptional level. Aberrant expression of oncogenic and tumor-suppressor microRNAs has been recognized as a common feature of human cancers. Colorectal cancer represents a major clinical challenge in the developed world and the design of innovative therapeutic approaches relies on the identification of novel biological targets. Here, we perform a functional screening in colorectal cancer cells using a library of locked nucleic acid (LNA)-modified anti-miRs in order to unveil putative oncogenic microRNAs whose inhibition yields a cytotoxic effect. We identify miR-1285-3p and further explore the effect of its targeting in both commercial cell lines and primary colorectal cancer stem cells, finding induction of cell cycle arrest and apoptosis. We show that DAPK2, a known tumor-suppressor, is a novel miR-1285 target and mediates both the anti-proliferative and the pro-apoptotic effects of miR-1285 depletion. Altogether, our findings uncover a novel oncogenic microRNA in colorectal cancer and lay the foundation for further studies aiming at the development of possible therapeutic strategies based on miR-1285 targeting.

Exosomal miR-21 regulates the TETs/PTENp1/PTEN pathway to promote hepatocellular carcinoma growth

Background

As an important means of communication, exosomes play an important role in the development of hepatocellular carcinoma (HCC).

Methods

Bioinformatics analysis, dual-luciferase reporter assays, methylation-specific quantitative PCR, and ChIP-PCR analysis were used to gain insight into the underlying mechanism of miR-21 in HCC.

Results

The detection of miRNAs in exosomes of HCC showed that miR-21 expression in exosomes was positively correlated with the expression level of miR-21 in cells and negatively correlated with the expression of its target genes PTEN, PTENp1 and TETs. HCC cell-derived exosomes could increase miR-21 and p-Akt expression in HCC cells and downregulate the expression of PTEN, PTENp1 and TETs. MiR-21 inhibitors or PTENp1 overexpression vectors could weaken the effect of the abovementioned exosomes and simultaneously weaken their role in promoting cell proliferation and migration and inhibiting apoptosis. Further studies showed that miR-21 not only directly regulated the expression of PTEN, PTENp1 and TETs but also increased the methylation level of the PTENp1 promoter by regulating the expression of TETs, thereby inhibiting the expression of PTENp1 and further downregulating the expression of PTEN.

Conclusions

Exosomal miR-21 can regulate the expression of the tumor suppressor genes PTEN and PTENp1 in various ways and affect the growth of HCC cells.

New insights into the genetics and epigenetics of systemic sclerosis

Systemic sclerosis (SSc) is a severe autoimmune disease that is characterized by vascular abnormalities, immunological alterations and fibrosis of the skin and internal organs. The results of genetic studies in patients with SSc have revealed statistically significant genetic associations with disease manifestations and progression. Nevertheless, genetic susceptibility to SSc is moderate, and the functional consequences of genetic associations remain only partially characterized. A current hypothesis is that, in genetically susceptible individuals, epigenetic modifications constitute the driving force for disease initiation. As epigenetic alterations can occur years before fibrosis appears, these changes could represent a potential link between inflammation and tissue fibrosis. Epigenetics is a fast-growing discipline, and a considerable number of important epigenetic studies in SSc have been published in the past few years that span histone post-translational modifications, DNA methylation, microRNAs and long non-coding RNAs. This Review describes the latest insights into genetic and epigenetic contributions to the pathogenesis of SSc and aims to provide an improved understanding of the molecular pathways that link inflammation and fibrosis. This knowledge will be of paramount importance for the development of medicines that are effective in treating or even reversing tissue fibrosis.

Downregulation of microRNA‑30a in bronchoalveolar lavage fluid from idiopathic pulmonary fibrosis patients

MicroRNAs (miRs) are short, highly conserved small noncoding RNA molecules with fundamental roles in regulating gene expression. To identify miR biomarkers associated with idiopathic pulmonary fibrosis (IPF), the expression pattern of miRs in exosomes from bronchoalveolar lavage fluid (BALF) of elderly patients with IPF were evaluated. High‑throughput quantitative detection of miR expression using a microarray indicated that miR‑125b, miR‑128, miR‑21, miR‑100, miR‑140‑3p and miR‑374b were upregulated in patients with IPF, while let‑7d, miR‑103, miR‑26 and miR‑30a‑5p were downregulated. The expression level of miR‑30a‑5p was further examined, and its potential target genes were predicted using target gene prediction analysis software. A direct regulatory association was confirmed between miR‑30a‑5p and TGF‑β activated kinase 1/MAP3K7 binding protein 3 (TAB3) via a dual‑luciferase reporter assay. Overexpression of miR‑30a‑5p decreased TAB3, α‑smooth muscle actin and fibronectin expression in A549 cells with or without transforming growth factor‑β1 treatment. The decreased expression of miR‑30a in the BALF of patients with IPF, along with the consequential increase in TAB3 expression, may be a crucial factor in IPF progression.

Regulation and Functional Significance of 5-Hydroxymethylcytosine in Cancer

Epigenetic modes of gene regulation are important for physiological conditions and its aberrant changes can lead to disease like cancer. 5-hydroxymethylcytosine (5hmC) is an oxidized form of 5-methylcytosine (5mC) catalyzed by Ten Eleven Translocation (TET) enzymes. 5hmC is considered to be a demethylation intermediate and is emerging as a stable and functional base modification. The global loss of 5hmC level is commonly observed in cancers and tumorigenic germline mutations in IDH, SDH and FH are found to be inhibiting TET activity. Although a global loss of 5hmC is characteristic in cancers, locus-specific 5hmC gain implicates selective gene expression control. The definitive role of 5hmC as a tumor suppressing or promoting modification can be deduced by identifying locus-specific 5hmC modification in different types of cancer. Determining the genes carrying 5hmC modifications and its selective variation will open up new therapeutic targets. This review outlines the role of global and locus-specific changes of 5hmC in cancers and the possible mechanisms underlying such changes. We have described major cellular factors that influence 5hmC levels and highlighted the significance of 5hmC in tumor micro environmental condition like hypoxia.

Interaction network of coexpressed mRNA, miRNA, and lncRNA activated by TGF‑β1 regulates EMT in human pulmonary epithelial cell

Noncoding RNAs (ncRNAs), such as microRNAs (miRNAs) and long noncoding RNAs (lncRNAs), play increasingly important roles in pathological processes involved in disease development. However, whether mRNAs interact with miRNAs and lncRNAs to form an interacting regulatory network in diseases remains unknown. In this study, the interaction of coexpressed mRNAs, miRNAs and lncRNAs during tumor growth factor-β1-activated (TGF-β1) epithelial-mesenchymal transition (EMT) was systematically analyzed in human alveolar epithelial cells. For EMT regulation, 24 mRNAs, 11 miRNAs and 33 lncRNAs were coexpressed, and interacted with one another. The interaction among coexpressed mRNAs, miRNAs and lncRNAs were further analyzed, and the results showed the lack of competing endogenous RNAs (ceRNAs) among them. The mutual regulation may be correlated with other modes, such as histone modification and transcription factor recruitment. However, the possibility of ceRNA existence cannot be ignored because of the generally low abundance of lncRNAs and frequent promiscuity of protein-RNA interactions. Thus, conclusions need further experimental identification and validation. In this context, disrupting many altered disease pathways remains one of the challenges in obtaining effective pathway-based therapy. The reason being that one specific mRNA, miRNA or lncRNA may target multiple genes that are potentially implicated in a disease. Nevertheless, the results of the present study provide basic mechanistic information, possible biomarkers and novel treatment strategies for diseases, particularly pulmonary tumor and fibrosis.