Pulmonary microRNA profiling: implications in upper lobe predominant lung disease

Multipotent adult progenitor cells prevent functional impairment and improve development in inflammation driven detriment of preterm ovine lungs

Background

Perinatal inflammation increases the risk for bronchopulmonary dysplasia in preterm neonates, but the underlying pathophysiological mechanisms remain largely unknown. Given their anti-inflammatory and regenerative capacity, multipotent adult progenitor cells (MAPC) are a promising cell-based therapy to prevent and/or treat the negative pulmonary consequences of perinatal inflammation in the preterm neonate. Therefore, the pathophysiology underlying adverse preterm lung outcomes following perinatal inflammation and pulmonary benefits of MAPC treatment at the interface of prenatal inflammatory and postnatal ventilation exposures were elucidated.

Methods

Instrumented ovine fetuses were exposed to intra-amniotic lipopolysaccharide (LPS 5 mg) at 125 days gestation to induce adverse systemic and peripheral organ outcomes. MAPC (10 × 106 cells) or saline were administered intravenously two days post LPS exposure. Fetuses were delivered preterm five days post MAPC treatment and either killed humanely immediately or mechanically ventilated for 72 h.

Results

Antenatal LPS exposure resulted in inflammation and decreased alveolar maturation in the preterm lung. Additionally, LPS-exposed ventilated lambs showed continued pulmonary inflammation and cell junction loss accompanied by pulmonary edema, ultimately resulting in higher oxygen demand. MAPC therapy modulated lung inflammation, prevented loss of epithelial and endothelial barriers and improved lung maturation in utero. These MAPC-driven improvements remained evident postnatally, and prevented concomitant pulmonary edema and functional loss.

Conclusion

In conclusion, prenatal inflammation sensitizes the underdeveloped preterm lung to subsequent postnatal inflammation, resulting in injury, disturbed development and functional impairment. MAPC therapy partially prevents these changes and is therefore a promising approach for preterm infants to prevent adverse pulmonary outcomes.

Three-dimensional analysis reveals a high incidence of lung adenocarcinoma in the upper region

PURPOSE

The lung is a unique organ with a ventilation-perfusion mismatch, which can cause inhomogeneous incidence rates of lung cancer depending on the location in the lung. We aimed to evaluate the incidence of lung adenocarcinoma in each lobe by analyzing the incidence per unit volume, to evaluate the incidence without being affected by differences in the size of each lobe or in the size of the lungs between individuals.

METHODS

The number of adenocarcinomas in each lobe was counted. Lung volumes were measured using a three-dimensional computer workstation. The tumor incidence per unit volume was analyzed based on the number of tumors in each lobe.

RESULTS

The number of tumors per unit volume was 0.467 in the right upper lobe (RUL), 0.182 in the right middle lobe, 0.209 in the right lower lobe, 0.306 in the left upper segment (LUS), 0.083 in the left lingular segment, and 0.169 in the left lower lobe. The tumor incidence rate of RUL + LUS was 2.269 times that of the other lobes, a value that was significantly higher when using the bootstrap method (p < 0.001).

CONCLUSIONS

The incidence of adenocarcinoma per unit volume in both upper lobes was higher than that in other lobes.

Extracellular vesicles secreted by primary human bronchial epithelial cells reduce Pseudomonas aeruginosa burden and inflammation in cystic fibrosis mouse lung

Cystic fibrosis (CF) results in a reduction in the volume of airway surface liquid, increased accumulation of viscous mucus, persistent antibiotic-resistant lung infections that cause chronic inflammation, and a decline in lung function. More than 50% of adults with CF are chronically colonized by Pseudomonas aeruginosa (P. aeruginosa), the primary reason for morbidity and mortality in people with CF (pwCF). Although highly effective modulator therapy (HEMT) is an important part of disease management in CF, HEMT does not eliminate P. aeruginosa or lung inflammation. Thus, new treatments are required to reduce lung infection and inflammation in CF. In a previous in vitro study, we demonstrated that primary human bronchial epithelial cells (HBECs) secrete extracellular vesicles (EVs) that block the ability of P. aeruginosa to form biofilms by reducing the abundance of several proteins necessary for biofilm formation as well as enhancing the sensitivity of P. aeruginosa to β-lactam antibiotics. In this study, using a CF mouse model of P. aeruginosa infection, we demonstrate that intratracheal administration of EVs secreted by HBEC reduced P. aeruginosa lung burden and several proinflammatory cytokines including IFN-γ, TNF-α, and MIP-1β in bronchoalveolar lavage fluid (BALF), even in the absence of antibiotics. Moreover, EVs decreased neutrophils in BALF. Thus, EVs secreted by HBEC reduce the lung burden of P. aeruginosa, decrease inflammation, and reduce neutrophils in a CF mouse model. These results suggest that HBEC via the secretion of EVs may play an important role in the immune response to P. aeruginosa lung infection.NEW & NOTEWORTHY Our findings show that extracellular vesicles secreted by primary human bronchial epithelial cells significantly reduce Pseudomonas aeruginosa burden, inflammation, and weight loss in a cystic fibrosis mouse model of infection.

The Binding of Pseudomonas aeruginosa to Cystic Fibrosis Bronchial Epithelial Model Cells Alters the Composition of the Exosomes They Produce Compared to Healthy Control Cells

Cystic fibrosis (CF) is a genetic disease that causes dehydration of the surface of the airways, increasing lung infections, most frequently caused by Pseudomonas aeruginosa. Exosomes are nanovesicles released by cells that play an essential role in intercellular communication, although their role during bacterial infections is not well understood. In this article, we analyze the alterations in exosomes produced by healthy bronchial epithelial and cystic fibrosis cell lines caused by the interaction with P. aeruginosa. The proteomic study detected alterations in 30% of the species analyzed. In healthy cells, they mainly involve proteins related to the extracellular matrix, cytoskeleton, and various catabolic enzymes. In CF, proteins related to the cytoskeleton and matrix, in addition to the proteasome. These differences could be related to the inflammatory response. A study of miRNAs detected alterations in 18% of the species analyzed. The prediction of their potential biological targets identified 7149 genes, regulated by up to 7 different miRNAs. The identification of their functions showed that they preferentially affected molecules involved in binding and catalytic activities, although with differences between cell types. In conclusion, this study shows differences in exosomes between CF and healthy cells that could be involved in the response to infection.

Mechanisms and Effects of Macrophage Polarization and Its Specifics in Pulmonary Environment

Macrophages are a specific group of cells found in all body tissues. They have specific characteristics in each of the tissues that correspond to the functional needs of the specific environment. These cells are involved in a wide range of processes, both pro-inflammatory and anti-inflammatory ("wound healing"). This is due to their specific capacity for so-called polarization, a phenotypic change that is, moreover, partially reversible compared to other differentiated cells of the human body. This promises a wide range of possibilities for its influence and thus therapeutic use. In this article, we therefore review the mechanisms that cause polarization, the basic classification of polarized macrophages, their characteristic markers and the effects that accompany these phenotypic changes. Since the study of pulmonary (and among them mainly alveolar) macrophages is currently the focus of scientific interest of many researchers and these macrophages are found in very specific environments, given mainly by the extremely high partial pressure of oxygen compared to other locations, which specifically affects their behavior, we will focus our review on this group.

Non-Coding RNAs in Pulmonary Diseases: Comparison of Different Airway-Derived Biosamples

Due to their structural conservation and functional role in critical signalling pathways, non-coding RNA (ncRNA) is a promising biomarker and modulator of pathological conditions. Most research has focussed on the role of microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs). These molecules have been investigated both in a cellular and an extracellular context. Sources of ncRNAs may include organ-specific body fluids. Therefore, studies on ncRNAs in respiratory diseases include those on sputum, bronchoalveolar lavage fluid (BALF) and exhaled breath condensate (EBC). It is worth identifying the limitations of these biosamples in terms of ncRNA abundance, processing and diagnostic potential. This review describes the progress in the literature on the role of ncRNAs in the pathogenesis and progression of severe respiratory diseases, including cystic fibrosis, asthma and interstitial lung disease. We showed that there is a deficit of information on lncRNAs and circRNAs in selected diseases, despite attempts to functionally bind them to miRNAs. miRNAs remain the most well-studied, but only a few investigations have been conducted on the least invasive biosample material, i.e., EBC. To summarise the studies conducted to date, we also performed a preliminary in silico analysis of the reported miRNAs, demonstrating the complexity of their role and interactions in selected respiratory diseases.

Human Umbilical Cord Mesenchymal Stem Cell-Derived Exosome Repairs Endometrial Epithelial Cells Injury Induced by Hypoxia via Regulating miR-663a/CDKN2A Axis

Aim

Thin endometrium remains a severe clinical challenge with no effective therapy to date. We aimed at exploring the role and molecular mechanism of human umbilical cord mesenchymal stem cell- (hucMSC-) derived exosomes (hucMSC-Ex) in repairing hypoxic injury of endometrial epithelial cells (EECs).

Methods

Exosomes were harvested from the conditioned medium of hucMSC and characterized using western blot, transmission electron microscopy (TEM), flow cytometry, and nanoparticle tracking analysis (NTA). EECs were subjected to hypoxic conditions before cocultured with hucMSC-Ex. Cell viability, apoptosis, and migration were determined with CCK-8, flow cytometry, and wound healing assay, respectively. Apoptosis/EMT-related proteins were detected by western blot. The miRNA profiling was determined by RNA sequencing. The expression of miR-663a and CDKN2A was measured by qRT-PCR. MiR-663a in EECs was overexpressed by transfecting with miR-663a mimics.

Results

Mesenchymal stem cells (MSCs) markers CD73, CD90, and CD106 were positively expressed in hucMSCs. Exosome isolated from hucMSC expressed CD63 and TSG101, and were 100-150 nm in diameter. HucMSC-Ex promoted cell proliferation inhibited by hypoxia. And hucMSC-Ex also inhibited hypoxia-induced apoptosis, migration, and EMT of EECs by upregulating the expression of Bcl-2 and E-cadherin and downregulating Bax and N-cadherin levels. Further, bioinformatics research found that hucMSC-Ex coculture can significantly upregulate the expression of miR-663a and decrease the expression of CDKN2A in hypoxia-induced EECs. Furthermore, miR-663a overexpression inhibited CDKN2A expression and increased the expression of Bcl-2 and E-cadherin in hypoxia-induced EECs.

Conclusions

HucMSC-Ex promoted cell proliferation, inhibited cell apoptosis, migration, and EMT in hypoxia-induced EECs, thereby alleviating hypoxia-induced EECs injury, which may be related to its regulation of miR-663a/CDKN2A expression. Our study indicated that hucMSC-Ex might benefit for repairing thin endometrium.

The Emerging Role of Extracellular Vesicles Detected in Different Biological Fluids in COPD

The pathogenesis of chronic obstructive pulmonary disease (COPD) is characterized by complex cellular and molecular mechanisms, not fully elucidated so far. It involves inflammatory cells (monocytes/macrophages, neutrophils, lymphocytes), cytokines, chemokines and, probably, new players yet to be clearly identified and described. Chronic local and systemic inflammation, lung aging and cellular senescence are key pathological events in COPD development and progression over time. Extracellular vesicles (EVs), released by virtually all cells both as microvesicles and exosomes into different biological fluids, are involved in intercellular communication and, therefore, represent intriguing players in pathobiological mechanisms (including those characterizing aging and chronic diseases); moreover, the role of EVs as biomarkers in different diseases, including COPD, is rapidly gaining recognition. In this review, after recalling the essential steps of COPD pathogenesis, we summarize the current evidence on the roles of EVs collected in different biological mediums as biomarkers in COPD and as potential players in the specific mechanisms leading to disease development. We will also briefly review the data on EV as potential therapeutic targets and potential therapeutic agents.

Extracellular Vesicles as Central Mediators of COPD Pathophysiology

Chronic obstructive pulmonary disease (COPD) is a complex, heterogeneous, smoking-related disease of significant global impact. The complex biology of COPD is ultimately driven by a few interrelated processes, including proteolytic tissue remodeling, innate immune inflammation, derangements of the host-pathogen response, aberrant cellular phenotype switching, and cellular senescence, among others. Each of these processes are engendered and perpetuated by cells modulating their environment or each other. Extracellular vesicles (EVs) are powerful effectors that allow cells to perform a diverse array of functions on both adjacent and distant tissues, and their pleiotropic nature is only beginning to be appreciated. As such, EVs are candidates to play major roles in these fundamental mechanisms of disease behind COPD. Furthermore, some such roles for EVs are already established, and EVs are implicated in significant aspects of COPD pathogenesis. Here, we discuss known and potential ways that EVs modulate the environment of their originating cells to contribute to the processes that underlie COPD.

Expression of the microRNA-30 family in pulmonary arterial hypertension and the role of microRNA-30d-5p in the regulation of pulmonary arterial smooth muscle cell toxicity and apoptosis

The biological processes of pulmonary artery vascular smooth muscle cells (PA-SMCs) and pulmonary artery endothelial cells in pulmonary arterial hypertension (PAH) are generally abnormal, with increased levels of proliferation and reduced levels of apoptosis. Although microRNAs (miRNAs/miRs) participate in a number of biological processes in a variety of diseases, such as tumors and infections, studies on the association between miRNAs and PAH are limited. In the present study, blood samples were collected from 6 patients with patent ductus arteriosus. The experimental group included 3 patients with severe PAH, while the control group included 3 patients without PAH. Microarray technology was used to detect the presence of any associated miRNAs. Moreover, a rat PAH model was established via left lung resection followed by monocrotaline injection, involving a total of 8 rats in the PAH group and 8 untreated rat in the control group. Reverse transcription-quantitative PCR was performed to verify the expression levels of the miR-30 family in the animal model. miR-30d-5p mimics and anti-miR-30d-5p were transfected into primary cultured PA-SMCs. Levels of cytotoxicity and cell apoptosis were examined, and Notch-3 expression levels were studied using western blotting. The results of the present study demonstrated that miR-30d-5p expression was downregulated in both patient blood and animal models of the PAH group compared with control groups. In primary cultured PA-SMCs, overexpression of miR-30d-5p attenuated the platelet-derived growth factor-induced toxicity of PA-SMCs, while knockdown of miR-30d-5p resulted in the increased toxicity of PA-SMCs compared with control group. The apoptosis rate of PA-SMCs increased with the overexpression of miR-30d-5p compared with control group. Moreover, the expression levels of Notch-3 in the miR-30d-5p group were significantly reduced compared with the anti-miR-30d-5p and miR-NC groups. In total, 10 circulating miRNAs that may be associated with PAH were discovered in the present study. Moreover, the expression of the miR-30 family was verified in animal models in vivo, and seven miRNAs in this family were discovered that may be associated with PAH. Additionally, miR-30d-5p was downregulated in both patients with PAH and animal models compared with control groups. Thus, the results of the present study demonstrated that the regulatory mechanism underlying PA-SMCs may be via the Notch-3 signaling pathway.

Exposure to extracellular vesicles from Pseudomonas aeruginosa result in loss of DNA methylation at enhancer and DNase hypersensitive site regions in lung macrophages

Various pathogens use differing strategies to evade host immune response including modulating the host's epigenome. Here, we investigate if EVs secreted from P. aeruginosa alter DNA methylation in human lung macrophages, thereby potentially contributing to a dysfunctional innate immune response. Using a genome-wide DNA methylation approach, we demonstrate that P. aeruginosa EVs alter certain host cell DNA methylation patterns. We identified 1,185 differentially methylated CpGs (FDR < 0.05), which were significantly enriched for distal DNA regulatory elements including enhancer regions and DNase hypersensitive sites. Notably, all but one of the 1,185 differentially methylated CpGs were hypomethylated in association with EV exposure. Significantly hypomethylated CpGs tracked to genes including AXL, CFB and CCL23. Gene expression analysis identified 310 genes exhibiting significantly altered expression 48 hours post P. aeruginosa EV treatment, with 75 different genes upregulated and 235 genes downregulated. Some CpGs associated with cytokines such as CSF3 displayed strong negative correlations between DNA methylation and gene expression. Our infection model illustrates how secreted products (EVs) from bacteria can alter DNA methylation of the host epigenome. Changes in DNA methylation in distal DNA regulatory regions in turn can modulate cellular gene expression and potential downstream cellular processes.

Regulation of airway immunity by epithelial miRNAs

The airway epithelium is essential to protect the host from inhaled pathogens and particles. It maintains immune homeostasis and mediates tissue repair after injury. Inflammatory diseases of the airways are associated with failure of epithelial functions, including loss of barrier integrity that results in increased tissue permeability and immune activation; excessive mucus secretion and impaired mucociliary clearance that leads to airflow obstruction and microbial overgrowth; and dysregulation of cellular signals that promotes inflammation and alters tissue structure and airway reactivity. MicroRNAs play crucial roles in mounting appropriate cellular responses to environmental stimuli and preventing disease, using a common machinery and mechanism to regulate gene expression in epithelial cells, immune cells of hematopoietic origin, and other cellular components of the airways. Respiratory diseases are accompanied by dramatic changes in epithelial miRNA expression that drive persistent immune dysregulation. In this review, we discuss responses of the epithelium that promote airway immunopathology, with a focus on miRNAs that contribute to the breakdown of essential epithelial functions. We emphasize the emerging role of miRNAs in regulation of epithelial responses in respiratory health and their value as diagnostic and therapeutic targets.

The role of exosomes from BALF in lung disease

Exosomes are released from a variety of immune cells and nonimmune cells, the phospholipid vesicle bilayer membrane structure actively secreted into tissues. Recently, exosomes were demonstrated to be effectively delivered proteins, cholesterol, lipids, and amounts of DNA, mRNA, and noncoding RNAs to a target cell or tissue from a host cell. These can be detected in blood, urine, exhaled breath condensates, bronchoalveolar lavage fluid (BALF), ascites, and cerebrospinal fluid. BALF is a clinical examination method for obtaining alveolar cells and biochemical components, reflecting changes in the lungs, so it is also called liquid biopsy. Exosomes from BALF become a new method for intercellular communication and well‐documented in various pulmonary diseases. In chronic obstructive pulmonary disease (COPD), BALF exosomes can predict the degree of COPD damage and serve as an effective monitoring indicator for airflow limitation and airway remodeling. It also mediates antigen presentation in the airways to the adaptive immune system as well as costimulatory effects. Furthermore, BALF exosomes from acute lung injury and infective diseases are closely related to various infections and lack of oxygen status. BALF exosomes play an important role in the diagnosis and prognosis of lung cancer. The effect of immunomodulatory role for BALF exosomes in adaptive and innate immune responses has been studied in sarcoidosis. The intercellular communication in the microenvironment of BALF exosomes in pulmonary fibrosis and lung remodeling have been studied. In this review, we summarize the novel findings of exosomes in BALF, executed function by protein, miRNA, DNA cytokine, and so on in several pulmonary diseases.

Let-7b-5p in vesicles secreted by human airway cells reduces biofilm formation and increases antibiotic sensitivity of P. aeruginosa

Pseudomonas aeruginosa is an opportunistic pathogen that forms antibiotic-resistant biofilms, which facilitate chronic infections in immunocompromised hosts. We have previously shown that P. aeruginosa secretes outer-membrane vesicles that deliver a small RNA to human airway epithelial cells (AECs), in which it suppresses the innate immune response. Here, we demonstrate that interdomain communication through small RNA-containing membrane vesicles is bidirectional and that microRNAs (miRNAs) in extracellular vesicles (EVs) secreted by human AECs regulate protein expression, antibiotic sensitivity, and biofilm formation by P. aeruginosa Specifically, human EVs deliver miRNA let-7b-5p to P. aeruginosa, which systematically decreases the abundance of proteins essential for biofilm formation, including PpkA and ClpV1-3, and increases the ability of beta-lactam antibiotics to reduce biofilm formation by targeting the beta-lactamase AmpC. Let-7b-5p is bioinformatically predicted to target not only PpkA, ClpV1, and AmpC in P. aeruginosa but also the corresponding orthologs in Burkholderia cenocepacia, another notorious opportunistic lung pathogen, suggesting that the ability of let-7b-5p to reduce biofilm formation and increase beta-lactam sensitivity is not limited to P. aeruginosa Here, we provide direct evidence for transfer of miRNAs in EVs secreted by eukaryotic cells to a prokaryote, resulting in subsequent phenotypic alterations in the prokaryote as a result of this interdomain communication. Since let-7-family miRNAs are in clinical trials to reduce inflammation and because chronic P. aeruginosa lung infections are associated with a hyperinflammatory state, treatment with let-7b-5p and a beta-lactam antibiotic in nanoparticles or EVs may benefit patients with antibiotic-resistant P. aeruginosa infections.

MicroRNA Expression in Extracellular Vesicles from Nasal Lavage Fluid in Chronic Rhinosinusitis

Extracellular vesicles (EVs) are nanovesicles of endocytic origin released by cells and found in human bodily fluids. EVs contain both mRNA and microRNA (miRNA), which can be shuttled between cells, indicating their role in cell communication. This study investigated whether nasal secretions contain EVs and whether these EVs contain RNA. EVs were isolated from nasal lavage fluid (NLF) using sequential centrifugation. EVs were characterized and EV sizes were identified by transmission electron microscopy (TEM). In addition, EV miRNA expression was different in the chronic rhinosinusitis without nasal polyp (CRSsNP) and chronic rhinosinusitis with nasal polyp (CRSwNP) groups. The Kyoto encyclopedia gene and genome database (KEGG) database was used to identify pathways associated with changed miRNAs in each analysis group. Twelve miRNAs were differentially expressed in NLF-EVs of CRS patients versus HCs. In addition, eight miRNAs were differentially expressed in NLF-EVs of CRSwNP versus CRSsNP patients. The mucin-type O-glycan biosynthesis was a high-ranked predicted pathway in CRS patients versus healthy controls (HCs), and the Transforming growth factor beta (TGF-β) signaling pathway was a high-ranked predicted pathway in CRSwNP versus CRSsNP patients. We demonstrated the presence of and differences in NLF-EV miRNAs between CRS patients and HCs. These findings open up a broad and novel area of research on CRS pathophysiology as driven by miRNA cell communication.

CF monocyte-derived macrophages have an attenuated response to extracellular vesicles secreted by airway epithelial cells

Mutations in CFTR alter macrophage responses, for example, by reducing their ability to phagocytose and kill bacteria. Altered macrophage responses may facilitate bacterial infection and inflammation in the lungs, contributing to morbidity and mortality in cystic fibrosis (CF). Extracellular vesicles (EVs) are secreted by multiple cell types in the lungs and participate in the host immune response to bacterial infection, but the effect of EVs secreted by CF airway epithelial cells (AEC) on CF macrophages is unknown. This report examines the effect of EVs secreted by primary AEC on monocyte-derived macrophages (MDM) and contrasts responses of CF and wild type (WT) MDM. We found that EVs generally increase pro-inflammatory cytokine secretion and expression of innate immune genes in MDM, especially when EVs are derived from AEC exposed to Pseudomonas aeruginosa and that this effect is attenuated in CF MDM. Specifically, EVs secreted by P. aeruginosa exposed AEC (EV-PA) induced immune response genes and increased secretion of proinflammatory cytokines, chemoattractants, and chemokines involved in tissue repair by WT MDM, but these effects were less robust in CF MDM. We attribute attenuated responses by CF MDM to differences between CF and WT macrophages because EVs secreted by CF AEC or WT AEC elicited similar responses in CF MDM. Our findings demonstrate the importance of AEC EVs in macrophage responses and show that the Phe508del mutation in CFTR attenuates the innate immune response of MDM to EVs.

Electroacupuncture Inhibits Autophagy of Neuron Cells in Postherpetic Neuralgia by Increasing the Expression of miR-223-3p

Postherpetic neuralgia (PHN) is a complication of herpes zoster viral infection. Its main manifestations are continuous or intermittent burning-like and electroshock-like pain in the affected nerves. Electroacupuncture (EA) is widely used in clinical treatment and exerts effects in alleviating neuropathic pain. In this study, we investigated the effect and underlying mechanism of EA on PHN. Sprague-Dawley rats were treated with resiniferatoxin (RTX) to establish a PHN model and subjected to EA and/or miR-223-3p overexpression (OV) or interference. Mechanical withdrawal latency was measured as an indication of pain sensitivity. Hematoxylin-eosin staining and transmission electron microscopy were performed to observe neuron cell morphology and autophagic vacuoles, respectively. ELISA was performed to detect reactive oxygen species (ROS) production and the levels of tumor necrosis factor- (TNF-) α, inducible nitric oxide synthase (iNOS), interleukin- (IL-) 6, and IL-10. Changes in autophagy and apoptosis-related miRNAs were detected by immunofluorescence and qRT-PCR, respectively. In RTX-treated rats, OV and EA reduced pain sensitivity, decreased the number of eosinophils, and increased that of nerve cells. ROS generation and the levels of TNF-α and iNOS were significantly reduced, while those of IL-6 and IL-10 were increased. OV and EA induced fewer autophagic vacuoles than those in the model group. The expression of autophagy-related protein microtubule-associated protein 1 light chain 3-II, ATG9, and Rab1 was decreased by OV and EA, whereas that of P62 was increased. qRT-PCR revealed that miR-223-3p expression in the model group decreased but was increased by EA. EA inhibits neuron cell autophagy in PHN by increasing miR-223-3p expression.

Neutrophil-derived trail is a proinflammatory subtype of neutrophil-derived extracellular vesicles

Aims: Extracellular vesicles (EVs) are membrane-derived vesicles that mediate intercellular communications. Neutrophils produce different subtypes of EVs during inflammatory responses. Neutrophil-derived trails (NDTRs) are generated by neutrophils migrating toward inflammatory foci, whereas neutrophil-derived microvesicles (NDMVs) are thought to be generated by neutrophils that have arrived at the inflammatory foci. However, the physical and functional characteristics of neutrophil-derived EVs are incompletely understood. In this study, we aimed to investigate the differences between NDTRs and NDMVs. Methods: The generation of neutrophil-derived EVs were visualized by live-cell fluorescence images and the physical characteristics were further analyzed using nanotracking analysis assay, scanning electron microscopic analysis, and marker expressions. Functional characteristics of neutrophil-derived EVs were analyzed using assays for bactericidal activity, monocyte chemotaxis, phenotype polarization of macrophages, and miRNA sequencing. Finally, the effects of neutrophil-derived EVs on the acute and chronic inflammation were examined in vivo. Results: Both EVs share similar characteristics including stimulators, surface marker expression, bactericidal activity, and chemoattractive effect on monocytes via MCP-1. However, the integrin-mediated physical interaction was required for generation of NDTRs whereas NDMV generation was dependent on PI3K pathway. Interestingly, NDTRs contained proinflammatory miRNAs such as miR-1260, miR-1285, miR-4454, and miR-7975, while NDMVs contained anti-inflammatory miRNAs such as miR-126, miR-150, and miR-451a. Although both EVs were easily uptaken by monocytes, NDTRs enhanced proinflammatory macrophage polarization whereas NDMVs induced anti-inflammatory macrophage polarization. Moreover, NDTRs showed protective effects against lethality in a murine sepsis model and pathological changes in a murine chronic colitis model. Conclusion: These results suggest that NDTR is a proinflammatory subtype of neutrophil-derived EVs distinguished from NDMV.

Extracellular Vesicles from Pseudomonas aeruginosa Suppress MHC-Related Molecules in Human Lung Macrophages

Pseudomonas aeruginosa, a Gram-negative bacterium, is one of the most common pathogens colonizing the lungs of cystic fibrosis patients. P. aeruginosa secrete extracellular vesicles (EVs) that contain LPS and other virulence factors that modulate the host's innate immune response, leading to an increased local proinflammatory response and reduced pathogen clearance, resulting in chronic infection and ultimately poor patient outcomes. Lung macrophages are the first line of defense in the airway innate immune response to pathogens. Proper host response to bacterial infection requires communication between APC and T cells, ultimately leading to pathogen clearance. In this study, we investigate whether EVs secreted from P. aeruginosa alter MHC Ag expression in lung macrophages, thereby potentially contributing to decreased pathogen clearance. Primary lung macrophages from human subjects were collected via bronchoalveolar lavage and exposed to EVs isolated from P. aeruginosa in vitro. Gene expression was measured with the NanoString nCounter gene expression assay. DNA methylation was measured with the EPIC array platform to assess changes in methylation. P. aeruginosa EVs suppress the expression of 11 different MHC-associated molecules in lung macrophages. Additionally, we show reduced DNA methylation in a regulatory region of gene complement factor B (CFB) as the possible driving mechanism of widespread MHC gene suppression. Our results demonstrate MHC molecule downregulation by P. aeruginosa-derived EVs in lung macrophages, which is consistent with an immune evasion strategy employed by a prokaryote in a host-pathogen interaction, potentially leading to decreased pulmonary bacterial clearance.

MiRNA Expression Profile in the Airways is Altered during Pulmonary Exacerbation in Children with Cystic Fibrosis-A Preliminary Report

MicroRNAs are small non-coding RNAs that regulate immune response and inflammation. We assumed that miRNAs may be involved in the immune response during cystic fibrosis pulmonary exacerbations (CFPE) and that altered expression profile in the airways and blood may underlie clinical outcomes in CF pediatric patients. Methods: We included 30 pediatric patients diagnosed with cystic fibrosis. The biologic material (blood, sputum, exhaled breath condensate) was collected during pulmonary exacerbation and in stable condition. The miRNA expression profile from blood and sputum (n = 6) was done using the next-generation sequencing. For validation, selected four miRNAs were analyzed by qPCR in exosomes from sputum supernatant and exhaled breath condensate (n = 24). NGS analysis was done in Base Space, correlations of gene expression with clinical data were done in Statistica. Results: The miRNA profiling showed that four miRNAs (miR-223, miR-451a, miR-27b-3p, miR-486-5p) were significantly altered during pulmonary exacerbation in CF patients in sputum but did not differ significantly in blood. MiRNA differently expressed in exhaled breath condensate (EBC) and sputum showed correlation with clinical parameters in CFPE. Conclusion: MiRNA expression profile changes in the airways during pulmonary exacerbation in CF pediatric patients. We suggest that miRNA alterations during CFPE are restricted to the airways and strongly correlate with clinical outcome.

Exosomal miRNA signatures of pancreatic lesions

BACKGROUND

Pancreatic and peri-pancreatic neoplasms encompass a variety of histotypes characterized by a heterogeneous prognostic impact. miRNAs are considered efficient candidate biomarkers due to their high stability in tissues and body fluids. We applied Nanostring profiling of circulating exosomal miRNAs to distinct pancreatic lesions in order to establish a source for biomarker development.

METHODS

A series of 140 plasma samples obtained from patients affected by pancreatic ductal adenocarcinoma (PDAC, n = 58), pancreatic neuroendocrine tumors (PanNET, n = 42), intraductal papillary mucinous neoplasms (IPMN, n = 20), and ampulla of Vater carcinomas (AVC, n = 20) were analyzed. Comprehensive miRNA profiling was performed on plasma-derived exosomes. Relevant miRNAs were validated by qRT-PCR and in situ hybridization (ISH).

RESULTS

Lesion specific miRNAs were identified through multiple disease comparisons. Selected miRNAs were validated in the plasma by qRT-PCR and at tissue level by ISH. We leveraged the presence of clinical subtypes with each disease cohort to identify miRNAs that are differentially enriched in aggressive phenotypes.

CONCLUSIONS

This study shows that pancreatic lesions are characterized by specific exosomal-miRNA signatures. We also provide the basis for further explorations in order to better understand the relevance of these signatures in pancreatic neoplasms.

Viral strategies predisposing to respiratory bacterial superinfections

Acute respiratory infections are amongst the leading causes of childhood morbidity and mortality globally. Viruses are the predominant cause of such infections, but mixed etiologies with bacteria has for decades raised the question of the interplay between them in causality and determination of the outcome of such infections. In this review, we examine recent microbiological, biochemical, and immunological advances that contribute to elucidating the mechanisms by which infections by specific viruses enable bacterial infections in the airway, and exacerbate them. We analyze specific domains in which viruses play such facilitating role including enhancement of bacterial adhesion by unmasking cryptic receptors and upregulation of adhesion proteins, disruption of tight junction integrity favoring paracellular transmigration of bacteria and loss of epithelial barrier integrity, increased availability of nutrient, such as mucins and iron, alteration of innate and adaptive immune responses, and disabling defense against bacteria, and lastly, changes in airway microbiome that render the lung more vulnerable to pathogens. Separate exhaustive analysis of each domain focuses on individuals with cystic fibrosis (CF), in whom viruses may play a key role in paving the way for the primary injury that leads to permanence of bacterial pathogens, viruses may then serve as triggers for "CF exacerbations"; these constituting the signature and ultimately the outcome determinants of these patients.

Targeting airway inflammation in cystic fibrosis

Introduction: The major cause of morbidity and mortality in patients with cystic fibrosis (CF) is lung disease. Inflammation in the CF airways occurs from a young age and contributes significantly to disease progression and shortened life expectancy. Areas covered: In this review, we discuss the key immune cells involved in airway inflammation in CF, the contribution of the intrinsic genetic defect to the CF inflammatory phenotype, and anti-inflammatory strategies designed to overcome what is a critical factor in the pathogenesis of CF lung disease. Review of the literature was carried out using the MEDLINE (from 1975 to 2018), Google Scholar and The Cochrane Library databases. Expert opinion: Therapeutic interventions specifically targeting the defective CF transmembrane conductance regulator (CFTR) protein have changed the clinical landscape and significantly improved the outlook for CF. As survival estimates for people with CF increase, long-term management has become an important focus, with an increased need for therapies targeted at specific elements of inflammation, to complement CFTR modulator therapies.

Functional and metabolic impairment in cigarette smoke-exposed macrophages is tied to oxidative stress

Cigarette smoke inhalation exposes the respiratory system to thousands of potentially toxic substances and causes chronic obstructive pulmonary disease (COPD). COPD is characterized by cycles of inflammation and infection with a dysregulated immune response contributing to disease progression. While smoking cessation can slow the damage in COPD, lung immunity remains impaired. Alveolar macrophages (AMΦ) are innate immune cells strategically poised at the interface between lungs, respiratory pathogens, and environmental toxins including cigarette smoke. We studied the effects of cigarette smoke on model THP-1 and peripheral blood monocyte derived macrophages, and discovered a marked inhibition of bacterial phagocytosis which was replicated in primary human AMΦ. Cigarette smoke decreased AMΦ cystic fibrosis transmembrane conductance regulator (CFTR) expression, previously shown to be integral to phagocytosis. In contrast to cystic fibrosis macrophages, smoke-exposed THP-1 and AMΦ failed to augment phagocytosis in the presence of CFTR modulators. Cigarette smoke also inhibited THP-1 and AMΦ mitochondrial respiration while inducing glycolysis and reactive oxygen species. These effects were mitigated by the free radical scavenger N-acetylcysteine, which also reverted phagocytosis to baseline levels. Collectively these results implicate metabolic dysfunction as a key factor in the toxicity of cigarette smoke to AMΦ, and illuminate avenues of potential intervention.

DNA Methylation Changes in Regional Lung Macrophages Are Associated with Metabolic Differences

A number of pulmonary diseases occur with upper lobe predominance, including cystic fibrosis and smoking-related chronic obstructive pulmonary disease. In the healthy lung, several physiologic and metabolic factors exhibit disparity when comparing the upper lobe of the lung to lower lobe, including differences in oxygenation, ventilation, lymphatic flow, pH, and blood flow. In this study, we asked whether these regional differences in the lung are associated with DNA methylation changes in lung macrophages that could potentially lead to altered cell responsiveness upon subsequent environmental challenge. All analyses were performed using primary lung macrophages collected via bronchoalveolar lavage from healthy human subjects with normal pulmonary function. Epigenome-wide DNA methylation was examined via Infinium MethylationEPIC (850K) array and validated by targeted next-generation bisulfite sequencing. We observed 95 CpG loci with significant differential methylation in lung macrophages, comparing upper lobe to lower lobe (all false discovery rate < 0.05). Several of these genes, including CLIP4, HSH2D, NR4A1, SNX10, and TYK2, have been implicated as participants in inflammatory/immune-related biological processes. Functionally, we identified phenotypic differences in oxygen use, comparing upper versus lower lung macrophages. Our results support a hypothesis that epigenetic changes, specifically DNA methylation, at a multitude of gene loci in lung macrophages are associated with metabolic differences regionally in lung.

Reactive Oxygen Species Drive Epigenetic Changes in Radiation-Induced Fibrosis

Radiation-induced fibrosis (RIF) develops months to years after initial radiation exposure. RIF occurs when normal fibroblasts differentiate into myofibroblasts and lay down aberrant amounts of extracellular matrix proteins. One of the main drivers for developing RIF is reactive oxygen species (ROS) generated immediately after radiation exposure. Generation of ROS is known to induce epigenetic changes and cause differentiation of fibroblasts to myofibroblasts. Several antioxidant compounds have been shown to prevent radiation-induced epigenetic changes and the development of RIF. Therefore, reviewing the ROS-linked epigenetic changes in irradiated fibroblast cells is essential to understand the development and prevention of RIF.

Identification of miRNA-rich vesicles in bronchoalveolar lavage fluid: Insights into the function and heterogeneity of extracellular vesicles

Despite emerging interest in the role of extracellular vesicle (EV)-containing microRNAs (EV-miRNAs), the existence of functional EV-miRNAs under patho-physiological conditions has been viewed with skepticism. Due to the heterogenicity of EVs, several barriers related to EV-miRNA research are to be explored before the in vivo function of EV-miRNAs can be thoroughly delineated. For example, it has been reported that far less than one copy of a given miRNA can be detected per exosome. In this study, we demonstrated that miRNA-rich-EVs exist and can be consistently isolated using differential centrifugation & density-gradient fractionation from bronchoalveolar lavage fluid (BALF) in vivo. The absolute number of this 'miRNA-rich'-EV population is only about 7.05 × 10⁹ per mouse (6% of total EVs). However, the RNA amount detected in this population of EVs represents approximately 39% of the total EV RNAs in the BALF. In contrast, the remaining populations of BALF EVs (76% of total EVs) contain extremely low concentrations of RNAs and miRNAs. The miRNA-rich-EVs in BALF are likely derived from alveolar epithelial type-I cells (ATIs). Notably, caveolin-1, a lipid raft protein, is exclusively detected in the miRNA-rich-EVs, suggesting the lipid raft protein as a biomarker of EV-miRNA enrichment. We further demonstrated that miRNAs contained in the ATI-EVs are actively delivered into alveolar macrophages, subsequently promoting inflammasome activation, neutrophil recruitment, and M1-macrophage polarization in response to P. aeruginosa pneumonia in vitro and in vivo. Collectively, we are the first to identify and characterize the miRNA-rich-EVs in BALF. These miRNA-rich EVs endorse pro-inflammatory responses in bacterial lung infection. Our study provides a novel insight into the development of biomarkers, therapeutic strategies and underlying mechanisms for lung pathology.

Inflammation in cystic fibrosis: An update

Inflammation plays a critical role in cystic fibrosis (CF) lung pathology and disease progression making it an active area of research and important therapeutic target. In this review, we explore the most recent research on the major contributors to the exuberant inflammatory response seen in CF as well as potential therapeutics to combat this response. Absence of functional cystic fibrosis transmembrane conductance regulator (CFTR) alters anion transport across CF airway epithelial cells and ultimately results in dehydration of the airway surface liquid. The dehydrated airway surface liquid in combination with abnormal mucin secretion contributes to airway obstruction and subsequent infection that may serve as a trigger point for inflammation. There is also evidence to suggest that airway inflammation may be excessive and sustained relative to the infectious stimuli. Studies have shown dysregulation of both pro-inflammatory mediators such as IL-17 and pro-resolution mediators including metabolites of the eicosanoid pathway. Recently, CFTR potentiators and correctors have garnered much attention in the CF community. Although these modulators address the underlying defect in CF, their impact on downstream consequences such as inflammation are not known. Here, we review pre-clinical and clinical data on the impact of CFTR modulators on inflammation. In addition, we examine other cell types including neutrophils, macrophages, and T-lymphocytes that express CFTR and contribute to the CF inflammatory response. Finally, we address challenges in developing anti-inflammatory therapies and highlight some of the most promising anti-inflammatory drugs under development for CF.

Pre-Analytical Handling Conditions and Small RNA Recovery from Urine for miRNA Profiling

There are currently no standardized protocols for pre-analytical handling of urine to best preserve small RNA for miRNA profiling studies. miRNA is an attractive candidate as a potential biomarker because of the high level of stability in body fluids and its ability to be quantified on multiple high-throughput platforms. We present a comparison of small RNA recovery and stability in urine under alternate pre-analytical handling conditions and extend recommendations on what conditions optimize yield of miRNA from cell-free urine and urine extracellular vesicles (EVs). Using an affinity slurry for isolation of small RNA from urine, we found that urine samples held at room temperature (20°C) for up to 8 hours before processing yield the highest amounts of intact small RNAs from EVs. Some miRNA is lost from urine samples when held 2°C to 4°C and/or frozen before EV isolation, likely because of EV entrapment in uromodulin precipitates. However, we found that a simple 5-minute incubation of urine containing cold-induced precipitate at 37°C resolubilizes much of this precipitate and results in an increased recovery of EVs and miRNAs. Finally, small RNA integrity can be compromised when whole urine is held at 37°C for as little as 4 hours and is not conducive to efficient miRNA profiling.

MicroRNA regulatory networks reflective of polyhexamethylene guanidine phosphate-induced fibrosis in A549 human alveolar adenocarcinoma cells

Polyhexamethylene guanidine phosphate (PHMG-phosphate), an active component of humidifier disinfectant, is suspected to be a major cause of pulmonary fibrosis. Fibrosis, induced by recurrent epithelial damage, is significantly affected by epigenetic regulation, including microRNAs (miRNAs). The aim of this study was to investigate the fibrogenic mechanisms of PHMG-phosphate through the profiling of miRNAs and their target genes. A549 cells were treated with 0.75 μg/mL PHMG-phosphate for 24 and 48 h and miRNA microarray expression analysis was conducted. The putative mRNA targets of the miRNAs were identified and subjected to Gene Ontology analysis. After exposure to PHMG-phosphate for 24 and 48 h, 46 and 33 miRNAs, respectively, showed a significant change in expression over 1.5-fold compared with the control. The integrated analysis of miRNA and mRNA microarray results revealed the putative targets that were prominently enriched were associated with the epithelial-mesenchymal transition (EMT), cell cycle changes, and apoptosis. The dose-dependent induction of EMT by PHMG-phosphate exposure was confirmed by western blot. We identified 13 putative EMT-related targets that may play a role in PHMG-phosphate-induced fibrosis according to the Comparative Toxicogenomic Database. Our findings contribute to the comprehension of the fibrogenic mechanism of PHMG-phosphate and will aid further study on PHMG-phosphate-induced toxicity.

MiR-150 alleviates neuropathic pain via inhibiting toll-like receptor 5

MicroRNAs (miRNAs) are reported as vital participators in the pathophysiological course of neuropathic pain. However, the underlying mechanisms of the functional roles of miRNAs in neuropathic pain are largely unknown. This study was designed to explore the potential role of miR-150 in regulating the process of neuropathic pain in a rat model established by chronic sciatic nerve injury (CCI). Overexpression of miR-150 greatly alleviated neuropathic pain development and reduced inflammatory cytokine expression, including COX-2, interleukin IL-6, and tumor necrosis factor (TNF)-α in CCI rats. By bioinformatic analysis, 3'-untranslated region (UTR) of Toll-like receptor (TLR5) was predicted to be a target of miR-150. TLR5 commonly serves as an important regulator of inflammation. Overexpression of miR-150 significantly suppressed the expression of TLR5 in vitro and in vivo. Furthermore, upregulation of TLR5 decreased the miR-150 expression and downregulation of TLR5 increased miR-150, respectively. Overexpression of TLR5 significantly reversed the miR-150-induced suppressive effects on neuropathic pain. In conclusion, our current study indicates that miR-150 may inhibit neuropathic pain development of CCI rats through inhibiting TLR5-mediated neuroinflammation. Our findings suggest that miR-150 may provide a novel therapeutic target for neuropathic pain treatment.