Altered microRNA expression profile during epithelial wound repair in bronchial epithelial cells

Secretome Analysis of Human Nasal Fibroblast Identifies Proteins That Promote Wound Healing

Conditioned medium from cultured fibroblast cells is recognized to promote wound healing and growth through the secretion of enzymes, extracellular matrix proteins, and various growth factors and cytokines. The objective of this study was to profile the secreted proteins present in nasal fibroblast conditioned medium (NFCM). Nasal fibroblasts isolated from human nasal turbinates were cultured for 72 h in Defined Keratinocytes Serum Free Medium (DKSFM) or serum-free F12: Dulbecco's Modified Eagle's Medium (DMEM) to collect conditioned medium, denoted as NFCM_DKSFM and NFCM_FD, respectively. SDS-PAGE was performed to detect the presence of protein bands, followed by MALDI-TOF and mass spectrometry analysis. SignalP, SecretomeP, and TMHMM were used to identify the secreted proteins in conditioned media. PANTHER Classification System was performed to categorize the protein according to protein class, whereas STRING 10 was carried out to evaluate the predicted proteins interactions. SDS-PAGE results showed the presence of various protein with molecular weight ranging from ~10 kDa to ~260 kDa. Four protein bands were identified using MALDI-TOF. The analyses identified 104, 83, and 7 secreted proteins in NFCM_FD, NFCM_DKSFM, and DKSFM, respectively. Four protein classes involved in wound healing were identified, namely calcium-binding proteins, cell adhesion molecules, extracellular matrix proteins, and signaling molecules. STRING10 protein prediction successfully identified various pathways regulated by secretory proteins in NFCM. In conclusion, this study successfully profiled the secreted proteins of nasal fibroblasts and these proteins are predicted to play important roles in RECs wound healing through various pathways.

Interleukin-33-Dependent Accumulation of Regulatory T Cells Mediates Pulmonary Epithelial Regeneration During Acute Respiratory Distress Syndrome

Acute respiratory distress syndrome (ARDS) triggered mostly by infection, is a syndrome that involves respiratory failure. ARDS induces strong local infiltration of regulatory T cells (Treg cells) in the lungs, and Treg cells were recently highlighted as being related to the repair of various tissue. However, at present, there is still a lack of adequate evidence showing the impact of Treg cells on pulmonary regeneration during ARDS. Here, we verified that Treg cells are strongly induced in ARDS mice and Treg depletion results in impaired lung repair. Moreover, Treg cells show high expression of ST2, a cellular receptor for the tissue alarmin IL-33, which is strongly upregulated in the lung during ARDS. In addition, we demonstrated that IL-33 signaling is crucial for Treg cell accumulation, and ST2-blocked mice show a decrease in the Treg cell population. Critically, transfer of exogenous IL-33 into Treg depleted mice restored Treg cells and facilitated lung regeneration by promoting alveolar type II cell (AEC2) recovery in ARDS, with elevated neutrophils infiltration and upregulated TGF-β1 release. These results emphasized the importance of IL-33 in accelerating the expansion of pulmonary Treg cells and promoting their activity to mediate pulmonary epithelial regeneration during ARDS in a TGF-β1-dependent manner.

Tectorigenin regulates migration, invasion, and apoptosis in dexamethasone-induced human airway epithelial cells through up-regulating miR-222-3p

Glucocorticoids (GCs) can effectively control airway inflammation, but can also cause airway epithelial injury. Tectorigenin, a type of isoflavone isolated from various medicinal plants, has hypolipidemic activity, hepatoprotective, and antioxidant effects. We aimed to investigate whether Tectorigenin can repair GCs-induced airway epithelial injury. Airway epithelial cell line (9HTE cells) were treated with dexamethasone (Dex), Tectorigenin, or further transfected, then cell viability, migration, and invasion were examined by Cell Counting Kit (CCK-8), wound healing, and Transwell assays. The expressions of potential miRNAs related to the effect of Tectorigenin were detected by quantitative polymerase chain reaction (qPCR). Expressions of poptosis-related proteins Bcl-2-associated protein-X (Bax), B-cell lymphoma-2 (Bcl-2), Cleaved Caspase-3, and related to Mitorgen-activated protein kinase (MAPK) signaling pathway serine/threonine kinase (Raf1), extracellular signal-regulated kinase kinase 1/2 (MEK1/2), and extracellular signal-regulated kinase 1/2 (ERK1/2) were detected by Western blot. Dex inhibited the cell viability, migration and invasion by promoting Bax and Cleaved Caspase-3 expressions (p <.001) and by inhibiting the expressions of Bcl-2 and miR-222-3p (p <.001). Then, 10 μmol/L Tectorigenin itself did not affect cell viability but could inhibit the effect of Dex on cell viability, migration, and invasion. Tectorigenin up-regulated the expressions of miR-222-3p, Bcl-2, p-Raf1, p-MEK1/2, and p-ERK1/2 (p <.01), but down-regulated the expressions of Bax and Cleaved Caspase-3 (p <.05) in Dex-induced cells. MiR-222-3p inhibitor reversed the antagonistic effect of Tectorigenin on Dex. The study demonstrates that Tectorigenin inhibits apoptosis of Dex-induced 9HTE cells by up-regulating the expression of miR-222-3p, which involves with the MAPK pathway.

MiR-222-3p ameliorates glucocorticoid-induced inhibition of airway epithelial cell repair through down-regulating GILZ expression

GILZ expression is induced by glucocorticoids (GCs) and is involved in the mechanism of airway epithelial cell repair in patients with asthma. The present study aimed to investigate the role of miR-222-3p/GILZ pathway in treatment of airway epithelial cell repair by GCs. 9HTE cells were treated by 10 µmol/L dexamethasone (Dex) for 6, 12, and 24 hours (h). MiR-222-3p mimic and GILZ were used for cell transfection. Cell vitality, migration, and invasion were detected by methyl-thiazolyl tetrazolium (MTT), wound healing, and Transwell. The targeting relationship between miR-222-3p and GILZ was predicted by TargetScan and further confirmed by dual-luciferase reporter assay. The expressions of relative mRNAs or proteins were detected by Western blot and quantitative polymerase chain reaction (qPCR). The results showed that Dex treatment up-regulated the GILZ expression level but inhibited the levels of p-Raf1, p-MEK1/2, p-ERK1/2, and miR-222-3p of the cells, moreover, it also inhibited cell activity, migration, and invasion in a time-dependent manner. MiR-222-3p specifically targeted GILZ. MiR-222-3p mimic ameliorated the cell viability, migration, and invasion reduced by Dex treatment, increased the expression levels of p-Raf1 and p-MEK1/2, p-ERK1/2, and partially reversed the effects of GILZ overexpression on the above indexes. Moreover, GILZ showed the opposite effects to miR-222-3p. MiR-222-3p activated MAPK signaling pathway through inhibiting the GILZ expression, thus promoting the cell viability, migration, and invasion previously reduced by Dex.

Changes in miRNA Gene Expression during Wound Repair in Differentiated Normal Human Bronchial Epithelium

Purpose

Airway epithelium acts as a protective barrier against the particles from the inhaled air. Damage to the epithelium may result in loss of the barrier function. Epithelial repair in response to injury requires complex mechanisms, such as microRNA, small noncoding molecules, to regulate the processes involved in wound repair. We aimed to establish if the microRNA gene expression profile is altered during the airway epithelial repair in differentiated cells.

Methods

miRNA gene expression profile during the wound closure of differentiated normal human bronchial epithelium (NHBE) from one donor was analysed using quantitative real-time PCR. We have analysed the expression of 754 genes at five time points during a 48-hour period of epithelium repair using TaqMan Low Density Array.

Results

We found out that 233 miRNA genes were expressed in normal human bronchial epithelium. Twenty miRNAs were differentially expressed during the wound repair process, but only one (miR-455-3p) showed significance after FDR adjustment (p = 0.02). Using STEM, we have identified two clusters of several miRNA genes with similar expression profile. Pathway enrichment analysis showed several significant signaling pathways altered during repair, mainly involved in cell cycle regulation, proliferation, migration, adhesion, and transcription regulation.

Conclusions

miRNA expression profile is altered during airway epithelial repair of differentiated cells from one donor in response to mechanical injury in vitro, suggesting their potential role in wound repair.

Non-Coding RNAs in Pediatric Airway Diseases

Non-coding RNAs (ncRNAs) are involved in the regulation of numerous biological processes and pathways and therefore have been extensively studied in human diseases. Previous reports have shown that non-coding RNAs play a crucial role in the pathogenesis and aberrant regulation of respiratory diseases. The altered expression of microRNAs (miRNAs) and long non-coding RNAs in blood and also locally in sputum or exhaled breath condensate influences lung function, immune response, and disease phenotype and may be used for the development of biomarkers specific for airway disease. In this review, we provide an overview of the recent works studying the non-coding RNAs in airway diseases, with a particular focus on chronic respiratory diseases of childhood. We have chosen the most common chronic respiratory condition—asthma—and the most severe, chronic disease of the airways—cystic fibrosis. Study of the altered expression of non-coding RNAs in these diseases may be key to better understanding their pathogenesis and improving diagnosis, while also holding promise for the development of therapeutic strategies using the regulatory potential of non-coding RNAs.

MicroRNA-328 is involved in wound repair process in human bronchial epithelial cells

Our aim was to investigate the role of microRNA on epithelial wound repair by global microRNA silencing. We have also analysed the influence of five miRNAs (miR-328, miR-342, miR-411, miR-609, miR-888, previously identified) on wound repair in 16HBE14o-bronchial epithelial cell line. Cells were transfected with siRNAs against human DROSHA and DICER1 or miRNA mimics or inhibitors. Wounding assays were performed and the cells were observed using time-lapse microscopy. The area of damage was calculated at chosen time points, followed by data analysis. Cells with silenced global miRNA expression showed a significantly slower repair rate compared to the control cells (p=0.001). For miR-328, we observed significantly delayed repair in cells transfected with the inhibitor compared to control (p=0.02). Global microRNA silencing significantly decreased the repair rate of airway epithelial cells in vitro, indicating an important role of miRNA in the regulation of wound repair and that miR-328, possibly involved in actin pathway, may be a potent modifier of this process.

Role of MicroRNA in the Lung's Innate Immune Response

The immune response to respiratory pathogens must be robust enough to defend the host yet properly constrained such that inflammation-induced tissue damage is avoided. MicroRNA (miRNA) are small noncoding RNA which posttranscriptionally influence gene expression. In this review, we discuss recent experimental evidence of the contribution of miRNA to the lung's response to bacterial and viral pathogens.

[Effects of fine particulate matter from on bronchial epithelial cells]

INTRODUCTION

Ambient air contains a variety of pollutants including solid particles. Human bronchial epithelial cells (HBEC) play a key role following inhalation of these toxic particles. In a cell culture system of HBEC, we investigated the effects of several fractions of Lyons air-derived particles on cell viability/proliferation and production of the inflammatory mediators IL-8 and TGF-β.

METHODS

Air particles were collected in Lyon (France) by filtration of the air and impaction on filters located on a tapered element oscillating microbalance. Several diameter-based fractions of particles were prepared. HBEC were then exposed to different concentrations of these fractions.

RESULTS

HBEC survival was not altered after 48hours of culture in the presence of particles regardless of their diameter and concentration. A dose-dependent inhibitory effect on cell growth was observed for all fractions. The particles caused an increase of both TGF-ß and Il-8 protein levels as a function of their diameters and/or concentrations.

CONCLUSION

Air-derived particle fractions exhibit both an inhibitory effect on cell proliferation and a pro-inflammatory activity on HBEC.

Airway epithelial repair in health and disease: Orchestrator or simply a player?

Epithelial cells represent the most important surface of contact in the body and form the first line of defence of the body to external environment. Consequently, epithelia have numerous roles in order to maintain a homeostatic defence barrier. Although the epithelium has been extensively studied over several decades, it remains the focus of new research, indicating a lack of understanding that continues to exist around these cells in specific disease settings. Importantly, evidence is emerging that airway epithelial cells in particular have varied complex functions rather than simple passive roles. One area of current interest is its role following injury. In particular, the epithelial-specific cellular mechanisms regulating their migration during wound repair remain poorly understood and remain an area that requires much needed investigation. A better understanding of the physiological, cellular and molecular wound repair mechanisms could assist in elucidating pathological processes that contribute to airway epithelial pathology. This review attempts to highlight migration-specific and cell-extracellular matrix (ECM) aspects of repair used by epithelial cells under normal and disease settings, in the context of human airways.

Downregulation of miRNAs during Delayed Wound Healing in Diabetes: Role of Dicer

Delayed wound healing is a major complication associated with diabetes and is a result of a complex interplay among diverse deregulated cellular parameters. Although several genes and pathways have been identified to be mediating impaired wound closure, the role of microRNAs (miRNAs) in these events is not very well understood. Here, we identify an altered miRNA signature in the prolonged inflammatory phase in a wound during diabetes, with increased infiltration of inflammatory cells in the basal layer of the epidermis. Nineteen miRNAs were downregulated in diabetic rat wounds (as compared with normal rat wound, d 7 postwounding) together with inhibited levels of the central miRNA biosynthesis enzyme, Dicer, suggesting that in wounds of diabetic rats, the decreased levels of Dicer are presumably responsible for miRNA downregulation. Compared with unwounded skin, Dicer levels were significantly upregulated 12 d postwounding in normal rats, and this result was notably absent in diabetic rats that showed impaired wound closure. In a wound-healing specific quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) array, 10 genes were significantly altered in the diabetic rat wound and included growth factors and collagens. Network analyses demonstrated significant interactions and correlations between the miRNA predicted targets (regulators) and the 10 wound-healing specific genes, suggesting altered miRNAs might fine-tune the levels of these genes that determine wound closure. Dicer inhibition prevented HaCaT cell migration and affected wound closure. Altered levels of Dicer and miRNAs are critical during delayed wound closure and offer promising targets to address the issue of impaired wound healing.