Exosome miR-371b-5p promotes proliferation of lung alveolar progenitor type II cells by using PTEN to orchestrate the PI3K/Akt signaling

Harmonising cellular conversations: decoding the vital roles of extracellular vesicles in respiratory system intercellular communications

Extracellular vesicles (EVs) released by various cells play crucial roles in intercellular communication within the respiratory system. This review explores the historical context and significance of research into extracellular vesicles. Categorised into exosomes (sized 30-150 nm), microvesicles (sized 50-1000 nm) and apoptotic bodies (sized 500-2000nm), based on their generation mechanisms, extracellular vesicles carry diverse cargoes of biomolecules, including proteins, lipids and nucleic acids. Respiratory ailments are the primary contributors to both mortality and morbidity across various populations globally, significantly impacting public health. Recent studies have underscored the pivotal role of extracellular vesicles, particularly their cargo content, in mediating intercellular communication between lung cells in respiratory diseases. This comprehensive review provides insights into extracellular vesicle mechanisms and emphasises their significance in major respiratory conditions, including acute lung injury, COPD, pulmonary hypertension, pulmonary fibrosis, asthma and lung cancer.

Particular exosomal micro-RNAs and gastrointestinal (GI) cancer cells' roles: Current theories

A diverse range of gastrointestinal tract disorders are called gastrointestinal (GI) malignancies. The transformation of normal cells into precursor cells, precursor cells into premalignant cells, and premalignant cells into cancerous cells is facilitated by the interaction of many modifiable and non-modifiable risk factors. Developing relevant therapy alternatives based on a better knowledge of the illness's aetiology is essential to enhance patient outcomes. The exosome is crucial in regulating intercellular interaction because it may send molecular signals to nearby or distant cells. Exosomes produced from cancer can introduce a variety of chemicals and vast concentrations of microRNA (miRNA) into the tumour microenvironment. These miRNAs significantly impact immunological evasion, metastasis, apoptosis resistance, and cell growth. Exosomal miRNAs, or exosomal miRNAs, are essential for controlling cancer resistance to apoptosis, according to mounting data. Exosomal miRNAs function as an interaction hub between cancerous cells and the milieu around them, regulating gene expression and various signalling pathways. Our research examines the regulatory function of exosomal miRNAs in mediating interactions between cancer cells and the stromal and immunological cells that make up the surrounding milieu.

Cell-derived biomimetic nanoparticles for the targeted therapy of ALI/ARDS

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are common clinical critical diseases with high morbidity and mortality. Especially since the COVID-19 outbreak, the mortality rates of critically ill patients with ARDS can be as high as 60%. Therefore, this problem has become a matter of concern to respiratory critical care. To date, the main clinical measures for ALI/ARDS are mechanical ventilation and drug therapy. Although ventilation treatment reduces mortality, it increases the risk of hyperxemia, and drug treatment lacks safe and effective delivery methods. Therefore, novel therapeutic strategies for ALI/ARDS are urgently needed. Developments in nanotechnology have allowed the construction of a safe, efficient, precise, and controllable drug delivery system. However, problems still encounter in the treatment of ALI/ARDS, such as the toxicity, poor targeting ability, and immunogenicity of nanomaterials. Cell-derived biomimetic nanodelivery drug systems have the advantages of low toxicity, long circulation, high targeting, and high bioavailability and show great therapeutic promises for ALI/ARDS owing to their acquired cellular biological features and some functions. This paper reviews ALI/ARDS treatments based on cell membrane biomimetic technology and extracellular vesicle biomimetic technology, aiming to achieve a significant breakthrough in ALI/ARDS treatments.

Distinct serum exosomal miRNA profiles detected in acute and asymptomatic dengue infections: A community-based study in Baiyun District, Guangzhou

Background

In recent years, research on exosomal miRNAs has provided new insights into exploring the mechanism of viral infection and disease prevention. This study aimed to investigate the serum exosomal miRNA expression profile of dengue-infected individuals through a community survey of dengue virus (DENV) infection.

Methods

A seroprevalence study of 1253 healthy persons was first conducted to ascertain the DENV infection status in Baiyun District, Guangzhou. A total of 18 serum samples, including 6 healthy controls (HC), 6 asymptomatic DENV infections (AsymptDI), and 6 confirmed dengue fever patients (AcuteDI), were collected for exosome isolation and then sRNA sequencing. Through bioinformatics analysis, we discovered distinct serum exosomal miRNA profiles among the different groups and identified differentially expressed miRNAs (DEMs). These findings were further validated by qRT-PCR.

Results

The community survey of DENV infection indicated that the DENV IgG antibody positivity rate among the population was 11.97 % in the study area, with asymptomatic infected individuals accounting for 93.06 % of the anti-DENV IgG positives. The age and Guangzhou household registration were associated with DENV IgG antibody positivity by logistic regression analysis. Distinct miRNA profiles were observed between healthy individuals and DENV infections. A total of 1854 miRNAs were identified in 18 serum exosome samples from the initial analysis of the sequencing data. Comparative analysis revealed 23 DEMs comprising 5 upregulated and 18 downregulated miRNAs in the DENV-infected group (mergedDI). In comparison to AcuteDI, 18 upregulated miRNAs were identified in AsymptDI. Moreover, functional enrichment of the predicted target genes of DEMs indicated that these miRNAs were involved in biological processes and pathways related to cell adhesion, focal adhesion, endocytosis, and ECM-receptor interaction. Eight DEMs were validated by qRT-PCR.

Conclusion

The Baiyun District of Guangzhou exhibits a notable proportion of asymptomatic DENV infections as suggested in other research, highlighting the need for enhanced monitoring and screening of asymptomatic persons and the elderly. Differential miRNA expression among healthy, symptomatic and asymptomatic DENV-infected individuals suggests their potential as biomarkers for distinguishing DENV infection and offers new avenues of investigating the mechanisms underlying DENV asymptomatic infections.

Mesenchymal stem cells and their extracellular vesicles as emerging therapeutic tools in the treatment of ischemic stroke

Ischemic stroke (IS) is a neurological condition characterized by severe long-term consequences and an unfavorable prognosis for numerous patients. Despite advancements in stroke treatment, existing therapeutic approaches possess certain limitations. However, accumulating evidence suggests that mesenchymal stem/stromal cells (MSCs) hold promise as a potential therapy for various neurological disorders, including IS, owing to their advantageous properties, such as immunomodulation and tissue regeneration. Additionally, MSCs primarily exert their therapeutic effects through the release of extracellular vesicles (EVs), highlighting the significance of their paracrine activities. These EVs are small double-layered phospholipid membrane vesicles, carrying a diverse cargo of proteins, lipids, and miRNAs that enable effective cell-to-cell communication. Notably, EVs have emerged as attractive substitutes for stem cell therapy due to their reduced immunogenicity, lower tumorigenic potential, and ease of administration and handling. Hence, this review summarizes the current preclinical and clinical studies performed to investigate the safety and therapeutic potential of MSCs and their EVs derived from different sources, including bone marrow, adipose tissue, umbilical cord blood, and Wharton's jelly in IS.

Tiny Guides, Big Impact: Focus on the Opportunities and Challenges of miR-Based Treatments for ARDS

Acute Respiratory Distress Syndrome (ARDS) is characterized by lung inflammation and increased membrane permeability, which represents the leading cause of mortality in ICUs. Mechanical ventilation strategies are at the forefront of supportive approaches for ARDS. Recently, an increasing understanding of RNA biology, function, and regulation, as well as the success of RNA vaccines, has spurred enthusiasm for the emergence of novel RNA-based therapeutics. The most common types of RNA seen in development are silencing (si)RNAs, antisense oligonucleotide therapy (ASO), and messenger (m)RNAs that collectively account for 80% of the RNA therapeutics pipeline. These three RNA platforms are the most mature, with approved products and demonstrated commercial success. Most recently, miRNAs have emerged as pivotal regulators of gene expression. Their dysregulation in various clinical conditions offers insights into ARDS pathogenesis and offers the innovative possibility of using microRNAs as targeted therapy. This review synthesizes the current state of the literature to contextualize the therapeutic potential of miRNA modulation. It considers the potential for miR-based therapeutics as a nuanced approach that incorporates the complexity of ARDS pathophysiology and the multifaceted nature of miRNA interactions.

Extracellular vesicles from Pneumocystis carinii-infected rats impair fungal viability but are dispensable for macrophage functions

Pneumocystis spp. are host obligate fungal pathogens that can cause severe pneumonia in mammals and rely heavily on their host for essential nutrients. The lack of a sustainable in vitro culture system poses challenges in understanding their metabolism, and the acquisition of essential nutrients from host lungs remains unexplored. Transmission electron micrographs show that extracellular vesicles (EVs) are found near Pneumocystis spp. within the lung. We hypothesized that EVs transport essential nutrients to the fungi during infection. To investigate this, EVs from P. carinii- and P. murina-infected rodents were biochemically and functionally characterized. These EVs contained host proteins involved in cellular, metabolic, and immune processes as well as proteins with homologs found in other fungal EV proteomes, indicating that Pneumocystis may release EVs. Notably, EV uptake by P. carinii indicated their potential involvement in nutrient acquisition and a possibility for using engineered EVs for efficient therapeutic delivery. However, EVs added to P. carinii in vitro did not show increased growth or viability, implying that additional nutrients or factors are necessary to support their metabolic requirements. Exposure of macrophages to EVs increased proinflammatory cytokine levels but did not affect macrophages' ability to kill or phagocytose P. carinii. These findings provide vital insights into P. carinii and host EV interactions, yet the mechanisms underlying P. carinii's survival in the lung remain uncertain. These studies are the first to isolate, characterize, and functionally assess EVs from Pneumocystis-infected rodents, promising to enhance our understanding of host-pathogen dynamics and therapeutic potential.IMPORTANCEPneumocystis spp. are fungal pathogens that can cause severe pneumonia in mammals, relying heavily on the host for essential nutrients. The absence of an in vitro culture system poses challenges in understanding their metabolism, and the acquisition of vital nutrients from host lungs remains unexplored. Extracellular vesicles (EVs) are found near Pneumocystis spp., and it is hypothesized that these vesicles transport nutrients to the pathogenic fungi. Pneumocystis proteins within the EVs showed homology to other fungal EV proteomes, suggesting that Pneumocystis spp. release EVs. While EVs did not significantly enhance P. carinii growth in vitro, P. carinii displayed active uptake of these vesicles. Moreover, EVs induced proinflammatory cytokine production in macrophages without compromising their ability to combat P. carinii. These findings provide valuable insights into EV dynamics during host-pathogen interactions in Pneumocystis pneumonia. However, the precise underlying mechanisms remain uncertain. This research also raises the potential for engineered EVs in therapeutic applications.

The Patent Landscape of mTOR and PTEN Targets

BACKGROUND

PTEN and mTOR signaling have many roles, including antiinflammatory, immunosuppressant and cancer.

OBJECTIVE

US patents were retrieved to show the current landscape of the mTOR and PTEN targets.

METHODS

PTEN and mTOR targets were analyzed by patent analysis. The U.S. granted patents from January 2003 to July 2022 were performed and analyzed.

RESULTS

The results showed that the mTOR target was more attractive in drug discovery than the PTEN target. Our findings indicated that most large global pharmaceutical companies focused the drug discovery related to the mTOR target. The present study demonstrated that mTOR and PTEN targets showed more applications in biological approaches compared to BRAF and KRAS targets. The chemical structures of the inhibitors of the mTOR target demonstrated some similar features to those of the inhibitors of KRAS targets.

CONCLUSION

At this stage, the PTEN target may not be an ideal target subjected to new drug discovery. The present study was the first one which demonstrated that the group of O=S=O may play a critical role in the chemical structures of mTOR inhibitors. It was the first time to show that a PTEN target may be suitably subjected to new therapeutic discovery efforts related to biological applications. Our findings provide a recent insight into therapeutic development for mTOR and PTEN targets.

Exosomal MicroRNAs: An Emerging Important Regulator in Acute Lung Injury

Acute lung injury (ALI) is a clinically life-threatening form of respiratory failure with a mortality of 30%-40%. Acute respiratory distress syndrome is the aggravated form of ALI. Exosomes are extracellular lipid vesicles ubiquitous in human biofluids with a diameter of 30-150 nm. They can serve as carriers to convey their internal cargo, particularly microRNA (miRNA), to the target cells involved in cellular communication. In disease states, the quantities of exosomes and the cargo generated by cells are altered. These exosomes subsequently function as autocrine or paracrine signals to nearby or distant cells, regulating various pathogenic processes. Moreover, exosomal miRNAs from multiple stem cells can provide therapeutic value for ALI by regulating different signaling pathways. In addition, changes in exosomal miRNAs of biofluids can serve as biomarkers for the early diagnosis of ALI. This study aimed to review the role of exosomal miRNAs produced by different sources participating in various pathological processes of ALI and explore their potential significance in the treatment and diagnosis.

Extracellular Vesicles from Pneumocystis carinii -Infected Rats Impair Fungal Viability but are Dispensable for Macrophage Functions

Pneumocystis spp. are host obligate fungal pathogens that can cause severe pneumonia in mammals and rely heavily on their host for essential nutrients. The lack of a sustainable in vitro culture system poses challenges in understanding their metabolism and the acquisition of essential nutrients from host lungs remains unexplored. Transmission electron micrographs show Extracellular Vesicles (EVs) are found near Pneumocystis spp. within the lung. We hypothesized that EVs transport essential nutrients to the fungi during infection. To investigate this, EVs from P. carinii and P. murina infected rodents were biochemically and functionally characterized. These EVs contained host proteins involved in cellular, metabolic, and immune processes as well as proteins with homologs found in other fungal EV proteomes, indicating Pneumocystis may release EVs. Notably, EV uptake by P. carinii indicated their potential involvement in nutrient acquisition and indicate a possibility for using engineered EVs for efficient therapeutic delivery. However, EVs added to P. carinii in vitro , did not show increased growth or viability, implying that additional nutrients or factors are necessary to support their metabolic requirements. Exposure of macrophages to EVs increased proinflammatory cytokine levels, but did not affect macrophages' ability to kill or phagocytose P. carinii . These findings provide vital insights into P. carinii and host EV interactions, yet the mechanisms underlying P. carinii 's survival in the lung remain uncertain. These studies are the first to isolate, characterize, and functionally assess EVs from Pneumocystis -infected rodents, promising to enhance our understanding of host-pathogen dynamics and therapeutic potential.

Exosomes: Potential Next-Generation Nanocarriers for the Therapy of Inflammatory Diseases

Inflammatory diseases are common pathological processes caused by various acute and chronic factors, and some of them are autoimmune diseases. Exosomes are fundamental extracellular vesicles secreted by almost all cells, which contain a series of constituents, i.e., cytoskeletal and cytosolic proteins (actin, tubulin, and histones), nucleic acids (mRNA, miRNA, and DNA), lipids (diacylglycerophosphates, cholesterol, sphingomyelin, and ceramide), and other bioactive components (cytokines, signal transduction proteins, enzymes, antigen presentation and membrane transport/fusion molecules, and adhesion molecules). This review will be a synopsis of the knowledge on the contribution of exosomes from different cell sources as possible therapeutic agents against inflammation, focusing on several inflammatory diseases, neurological diseases, rheumatoid arthritis and osteoarthritis, intestinal bowel disease, asthma, and liver and kidney injuries. Current knowledge indicates that the role of exosomes in the therapy of inflammation and in inflammatory diseases could be distinctive. The main limitations to their clinical translation are still production, isolation, and storage. Additionally, there is an urgent need to personalize the treatments in terms of the selection of exosomes; their dosages and routes of administration; and a deeper knowledge about their biodistribution, type and incidence of adverse events, and long-term effects of exosomes. In conclusion, exosomes can be a very promising next-generation therapeutic option, superior to synthetic nanocarriers and cell therapy, and can represent a new strategy of effective, safe, versatile, and selective delivery systems in the future.

Connection between Radiation-Regulating Functions of Natural Products and miRNAs Targeting Radiomodulation and Exosome Biogenesis

Exosomes are cell-derived membranous structures primarily involved in the delivery of the payload to the recipient cells, and they play central roles in carcinogenesis and metastasis. Radiotherapy is a common cancer treatment that occasionally generates exosomal miRNA-associated modulation to regulate the therapeutic anticancer function and side effects. Combining radiotherapy and natural products may modulate the radioprotective and radiosensitizing responses of non-cancer and cancer cells, but there is a knowledge gap regarding the connection of this combined treatment with exosomal miRNAs and their downstream targets for radiation and exosome biogenesis. This review focuses on radioprotective natural products in terms of their impacts on exosomal miRNAs to target radiation-modulating and exosome biogenesis (secretion and assembly) genes. Several natural products have individually demonstrated radioprotective and miRNA-modulating effects. However, the impact of natural-product-modulated miRNAs on radiation response and exosome biogenesis remains unclear. In this review, by searching through PubMed/Google Scholar, available reports on potential functions that show radioprotection for non-cancer tissues and radiosensitization for cancer among these natural-product-modulated miRNAs were assessed. Next, by accessing the miRNA database (miRDB), the predicted targets of the radiation- and exosome biogenesis-modulating genes from the Gene Ontology database (MGI) were retrieved bioinformatically based on these miRNAs. Moreover, the target-centric analysis showed that several natural products share the same miRNAs and targets to regulate radiation response and exosome biogenesis. As a result, the miRNA-radiomodulation (radioprotection and radiosensitization)-exosome biogenesis axis in regard to natural-product-mediated radiotherapeutic effects is well organized. This review focuses on natural products and their regulating effects on miRNAs to assess the potential impacts of radiomodulation and exosome biogenesis for both the radiosensitization of cancer cells and the radioprotection of non-cancer cells.

A Bibliometric Analysis of Mesenchymal Stem Cell-Derived Exosomes in Acute Lung Injury/Acute Respiratory Distress Syndrome from 2013 to 2022

BACKGROUND

Mesenchymal stem cell-derived exosomes (MSC-exosomes) have been found to effectively improve the systemic inflammatory response caused by acute lung injury and acute respiratory distress syndrome (ALI/ARDS), regulate systemic immune disorders, and help injured cells repair. The purpose of this study was to take a holistic view of the current status and trends of MSC-exosomes research in ALI/ARDS.

METHODS

Bibliometrix, Citespace and VOSviewer software were used for bibliometric analysis of the data. We analysed the world trends, country distribution, institution contribution, most relevant journals and authors, research hotspots, and research hotspots related to Coronavirus Disease 2019 (COVID-19) based on the data collected.

RESULTS

China possessed the largest number of publications, while the USA had the highest H-index and the number of citations. Both China and the USA had a high influence in this research field. The largest number of publications in the field of MSC-exosomes and ALI/ARDS were mainly from the University of California system. Stem Cell Research & Therapy published the largest number of papers in this scope. The author with the greatest contribution was LEE JW, and ZHU YG published an article in Stem Cell with the highest local citation score. The most frequent keyword and the latest research hotspot were "NF-κB" and "Coronavirus Disease 2019". Furthermore, our bibliometric analysis results demonstrated that MSC-exosomes intervention and treatment can effectively alleviate the inflammatory response caused by ALI/ARDS.

CONCLUSION

Our bibliometric study suggested the USA and China have a strong influence in this field. COVID-19-induced ALI/ARDS had become a hot topic of research.

Identification of the miRNAome in human fracture callus and nonunion tissues

Background

Nonunions remain a challenging post-traumatic complication that often leads to a financial and health burden that affects the patient's quality of life. Despite a wealth of knowledge about fracture repair, especially gene and more recently miRNA expression, much remains unknown about the molecular differences between normal physiological repair (callus tissue) and a nonunion. To probe this lack of knowledge, we embarked on a study that sought to identify and compare the human miRNAome of normal bone to that present in a normal fracture callus and those from two different classic nonunion types, hypertrophic and oligotrophic.

Methods

Normal bone and callus tissue samples were harvested during revision surgery from patients with physiological fracture repair and nonunions (hypertrophic and oligotrophic) and analyzed using histology. Also, miRNAs were isolated and screened using microarrays followed by bioinformatic analyses, including, differential expression, pathways and biological processes, as well as elucidation of target genes.

Results

Out of 30,424 mature miRNAs (from 203 organisms) screened via microarrays, 635 (∼2.1%) miRNAs were found to be upregulated and 855 (∼2.8%) downregulated in the fracture callus and nonunion tissues as compared to intact bone. As our tissue samples were derived from humans, we focused on the human miRNAs and out of the 4223 human miRNAs, 86 miRNAs (∼2.0%) were upregulated and 51 (∼1.2%) were downregulated. Although there were similarities between the three experimental samples, we also found specific miRNAs that were unique to individual samples. We further identified the predicted target genes from these differentially expressed miRNAs as well as the relevant biological processes, including specific signaling pathways that are activated in all three experimental samples.

Conclusion

Collectively, this is the first comprehensive study reporting on the miRNAome of intact bone as compared to fracture callus and nonunion tissues. Further, we identify specific miRNAs involved in normal physiological fracture repair as well as those of nonunions.

The translational potential of this article

The data generated from this study further increase our molecular understanding of the roles of miRNAs during normal and aberrant fracture repair and this knowledge can be used in the future in the development of miRNA-based therapeutics for skeletal regeneration.

Extracellular Vesicles' Role in the Pathophysiology and as Biomarkers in Cystic Fibrosis and COPD

In keeping with the extraordinary interest and advancement of extracellular vesicles (EVs) in pathogenesis and diagnosis fields, we herein present an update to the knowledge about their role in cystic fibrosis (CF) and chronic obstructive pulmonary disease (COPD). Although CF and COPD stem from a different origin, one genetic and the other acquired, they share a similar pathophysiology, being the CF transmembrane conductance regulator (CFTR) protein implied in both disorders. Various subsets of EVs, comprised mainly of microvesicles (MVs) and exosomes (EXOs), are secreted by various cell types that are either resident or attracted in the airways during the onset and progression of CF and COPD lung disease, representing a vehicle for metabolites, proteins and RNAs (especially microRNAs), that in turn lead to events as such neutrophil influx, the overwhelming of proteases (elastase, metalloproteases), oxidative stress, myofibroblast activation and collagen deposition. Eventually, all of these pathomechanisms lead to chronic inflammation, mucus overproduction, remodeling of the airways, and fibrosis, thus operating a complex interplay among cells and tissues. The detection of MVs and EXOs in blood and biological fluids coming from the airways (bronchoalveolar lavage fluid and sputum) allows the consideration of EVs and their cargoes as promising biomarkers for CF and COPD, although clinical expectations have yet to be fulfilled.

Stem cell-based therapy for pulmonary fibrosis

Pulmonary fibrosis (PF) is a chronic and relentlessly progressive interstitial lung disease in which the accumulation of fibroblasts and extracellular matrix (ECM) induces the destruction of normal alveolar structures, ultimately leading to respiratory failure. Patients with advanced PF are unable to perform physical labor and often have concomitant cough and dyspnea, which markedly impair their quality of life. However, there is a paucity of available pharmacological therapies, and to date, lung transplantation remains the only possible treatment for patients suffering from end-stage PF; moreover, the complexity of transplantation surgery and the paucity of donors greatly restrict the application of this treatment. Therefore, there is a pressing need for alternative therapeutic strategies for this complex disease. Due to their capacity for pluripotency and paracrine actions, stem cells are promising therapeutic agents for the treatment of interstitial lung disease, and an extensive body of literature supports the therapeutic efficacy of stem cells in lung fibrosis. Although stem cell transplantation may play an important role in the treatment of PF, some key issues, such as safety and therapeutic efficacy, remain to be resolved. In this review, we summarize recent preclinical and clinical studies on the stem cell-mediated regeneration of fibrotic lungs and present an analysis of concerning issues related to stem cell therapy to guide therapeutic development for this complex disease.

Diagnostic Potential of microRNAs in Extracellular Vesicles Derived from Bronchoalveolar Lavage Fluid for Pneumonia—A Preliminary Report

Current clinical needs require the development and use of rapid and effective diagnostic indicators to accelerate the identification of pneumonia and the process of microbiological diagnosis. MicroRNAs (miRNAs) in extracellular vesicles (EVs) have become attractive candidates for novel biomarkers to evaluate the presence and progress of many diseases. We assessed their performance as biomarkers of pneumonia. Patients were divided into the pneumonia group (with pneumonia) and the control group (without pneumonia). We identified and compared two upregulated miRNAs in EVs derived from bronchoalveolar lavage fluid (BALF-EVs) between the two groups (P_{miR–17–5p} = 0.009; P_{miR–193a–5p} = 0.031). Interestingly, in cell-debris pellets and EVs-free supernatants derived from bronchoalveolar lavage fluid (BALF-cell-debris pellets and BALF-EVs-free supernatants), total plasma, and EVs derived from plasma (plasma-EVs), the expression of miR–17–5p and miR–193a–5p showed no difference between pneumonia group and control group. In vitro experiments revealed that miR–17–5p and miR–193a–5p were strikingly upregulated in EVs derived from macrophages stimulated by lipopolysaccharide. MiR–17–5p (area under the curve, AUC: 0.753) and miR–193a–5p (AUC: 0.692) in BALF-EVs are not inferior to procalcitonin (AUC: 0.685) in the diagnosis of pneumonia. Furthermore, miR–17–5p and miR–193a–5p in BALF-EVs had a significantly higher specificity compared to procalcitonin and could be served as a potential diagnostic marker. MiR–17–5p and miR–193a–5p in EVs may be involved in lung inflammation by influencing the forkhead box O (FoxO) signaling pathway and protein processing in endoplasmic reticulum. This study is one of the few studies which focused on the potential diagnostic role of miRNAs in BALF-EVs for pneumonia and the possibility to use them as new biomarkers for a rapid and early diagnosis.

microRNA Expression Profile of Purified Alveolar Epithelial Type II Cells

Alveolar type II (ATII) cells are essential for the maintenance of the alveolar homeostasis. However, knowledge of the expression of the miRNAs and miRNA-regulated networks which control homeostasis and coordinate diverse functions of murine ATII cells is limited. Therefore, we asked how miRNAs expressed in ATII cells might contribute to the regulation of signaling pathways. We purified "untouched by antibodies" ATII cells using a flow cytometric sorting method with a highly autofluorescent population of lung cells. TaqMan® miRNA low-density arrays were performed on sorted cells and intersected with miRNA profiles of ATII cells isolated according to a previously published protocol. Of 293 miRNAs expressed in both ATII preparations, 111 showed equal abundances. The target mRNAs of bona fide ATII miRNAs were used for pathway enrichment analysis. This analysis identified nine signaling pathways with known functions in fibrosis and/or epithelial-to-mesenchymal transition (EMT). In particular, a subset of 19 miRNAs was found to target 21 components of the TGF-β signaling pathway. Three of these miRNAs (miR-16-5p, -17-5p and -30c-5p) were down-modulated by TGF-β1 stimulation in human A549 cells, and concomitant up-regulation of associated mRNA targets (BMPR2, JUN, RUNX2) was observed. These results suggest an important role for miRNAs in maintaining the homeostasis of the TGF-β signaling pathway in ATII cells under physiological conditions.

Advances in the use of exosomes for the treatment of ALI/ARDS

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a critical clinical syndrome with high morbidity and mortality. Currently, the primary treatment for ALI/ARDS is mainly symptomatic therapy such as mechanical ventilation and fluid management. Due to the lack of effective treatment strategies, most ALI/ARDS patients face a poor prognosis. The discovery of exosomes has created a promising prospect for the treatment of ALI/ARDS. Exosomes can exert anti-inflammatory effects, inhibit apoptosis, and promote cell regeneration. The microRNA contained in exosomes can participate in intercellular communication and play an immunomodulatory role in ALI/ARDS disease models. This review discusses the possible mechanisms of exosomes in ALI/ARDS to facilitate the development of innovative treatments for ALI/ARDS.

PTEN: An Emerging Potential Target for Therapeutic Intervention in Respiratory Diseases

Phosphatase and tensin homolog deleted on chromosome 10 (PTEN) is a potent tumor suppressor that regulates several key cellular processes, including proliferation, survival, genomic integrity, migration, and invasion, via PI3K-dependent and independent mechanisms. A subtle decrease in PTEN levels or catalytic activity is implicated not only in cancer but also in a wide spectrum of other diseases, including various respiratory diseases. A systemic overview of the advances in the molecular and cellular mechanisms of PTEN involved in the initiation and progression of respiratory diseases may offer novel targets for the development of effective therapeutics for the treatment of respiratory diseases. In the present review, we highlight the novel findings emerging from current research on the role of PTEN expression and regulation in airway pathological conditions such as asthma/allergic airway inflammation, pulmonary hypertension (PAH), chronic obstructive pulmonary disease (COPD), idiopathic pulmonary fibrosis (IPF), and other acute lung injuries (ALI). Moreover, we discuss the clinical implications of PTEN alteration and recently suggested therapeutic possibilities for restoration of PTEN expression and function in respiratory diseases.

Microvesicles Derived from Human Umbilical Cord Mesenchymal Stem Cells Enhance Alveolar Type II Cell Proliferation and Attenuate Lung Inflammation in a Rat Model of Bronchopulmonary Dysplasia

Although it is known that exosomes derived from human umbilical cord mesenchymal stem cells (hUCMSCs) alleviate hyperoxic lung injury of bronchopulmonary dysplasia (BPD) in animal models, the role of microvesicles (MVs) derived from hUCMSCs in BPD is poorly defined. Furthermore, antenatal inflammation has been linked to high risk of BPD in preterm infants. The purpose of this study was to explore whether MVs derived from hUCMSCs can preserve lung structure and function in an antenatal lipopolysaccharide- (LPS-) induced BPD rat model and to clarify the underlying mechanism. We demonstrate that antenatal LPS induced alveolar simplification, altered lung function, and dysregulated pulmonary vasculature, which restored by hUCMSCs and MVs treatment. Furthermore, MVs were large vesicles with a diameter of 100-900 nanometers and mostly uptaken by alveolar epithelial type II cells (AT2) and macrophages. Compared with the LPS-exposed group, MVs restored the AT2 cell number and SP-C expression in vivo and promoted the proliferation of AT2 cells in vitro. MVs also restored the level of IL-6 and IL-10 in lung homogenate. Additionally, PTEN/AKT and MAPK pathways were associated with the protection of MVs. Taken together, this study suggests MVs derived from hUCMSCs improve lung architecture and function in an antenatal LPS-induced BPD rat model by promoting AT2 cell proliferation and attenuating lung inflammation; thus, MVs provide a promising therapeutic vehicle for BPD treatment.

Chronic obstructive pulmonary disease and asthma: mesenchymal stem cells and their extracellular vesicles as potential therapeutic tools

Chronic lung diseases, such as chronic obstructive pulmonary disease (COPD) and asthma, are one of the most frequent causes of morbidity and mortality in the global. COPD is characterized by progressive loss of lung function through inflammation, apoptosis, and oxidative stress caused by chronic exposure to harmful environmental pollutants. Airway inflammation and epithelial remodeling are also two main characteristics of asthma. In spite of extensive efforts from researchers, there is still a great need for novel therapeutic approaches for treatment of these conditions. Accumulating evidence suggests the potential role of mesenchymal stem cells (MSCs) in treatment of many lung injuries due to their beneficial features including immunomodulation and tissue regeneration. Besides, the therapeutic advantages of MSCs are chiefly related to their paracrine functions such as releasing extracellular vesicles (EVs). EVs comprising exosomes and microvesicles are heterogeneous bilayer membrane structures loaded with various lipids, nucleic acids and proteins. Due to their lower immunogenicity, tumorigenicity, and easier management, EVs have appeared as favorable alternatives to stem cell therapies. Therefore, in this review, we provided an overview on the current understanding of the importance of MSCs and MSC-derived EVs from different sources reported in preclinical and clinical COPD and asthmatic models.

Many faces and functions of GSKIP: a temporospatial regulation view

Glycogen synthase kinase 3 (GSK3)-β (GSK3β) interaction protein (GSKIP) is one of the smallest A-kinase anchoring proteins that possesses a binding site for GSK3β. Recently, our group identified the protein kinase A (PKA)-GSKIP-GSK3β-X axis; knowledge of this axis may help us decipher the many roles of GSKIP and perhaps help explain the evolutionary reason behind the interaction between GSK3β and PKA. In this review, we highlight the critical and multifaceted role of GSKIP in facilitating PKA kinase activity and its function as a scaffolding protein in signaling pathways. We also highlight how these pivotal PKA and GSK3 kinases can control context-specific functions and interact with multiple target proteins, such as β-catenin, Drp1, Tau, and other proteins. GSKIP is a key regulator of multiple mechanisms because of not only its location at certain subcellular compartments but also its serial changes during the developmental process. Moreover, the involvement of critical upstream regulatory signaling pathways in GSKIP signaling in various cancers, such as miRNA (microRNA) and lncRNA (long noncoding RNA), may help in the identification of therapeutic targets in the era of precision medicine and personalized therapy. Finally, we emphasize on the model of the early stage of pathogenesis of Alzheimer Disease (AD). Although the model requires validation, it can serve as a basis for diagnostic biomarkers development and drug discovery for early-stage AD.

Autophagy regulates the effects of ADSC-derived small extracellular vesicles on acute lung injury

Small extracellular vesicles (sEVs) have been recognized to be more effective than direct stem cell differentiation into functional target cells in preventing tissue injury and promoting tissue repair. Our previous study demonstrated the protective effect of adipose-derived stem cells (ADSCs) on lipopolysaccharide (LPS)-induced acute lung injury and the effect of autophagy on ADSC functions, but the role of ADSC-derived sEVs (ADSC-sEVs) and autophagy-mediated regulation of ADSC-sEVs in LPS-induced pulmonary microvascular barrier damage remains unclear. After treatment with sEVs from ADSCs with or without autophagy inhibition, LPS-induced human pulmonary microvascular endothelial cell (HPMVECs) barrier damage was detected. LPS-induced acute lung injury in mice was assessed in vivo after intravenous administration of sEVs from ADSCs with or without autophagy inhibition. The effects of autophagy on the bioactive miRNA components of ADSC-sEVs were assessed after prior inhibition of cell autophagy. We found that ADSC-sEV effectively alleviated LPS-induced apoptosis, tight junction damage and high permeability of PMVECs. Moreover, in vivo administration of ADSC-sEV markedly inhibited LPS-triggered lung injury. However, autophagy inhibition, markedly weakened the therapeutic effect of ADSC-sEVs on LPS-induced PMVECs barrier damage and acute lung injury. In addition, autophagy inhibition, prohibited the expression of five specific miRNAs in ADSC-sEVs -under LPS-induced inflammatory conditions. Our results indicate that ADSC-sEVs protect against LPS-induced pulmonary microvascular barrier damage and acute lung injury. Autophagy is a positive mediator of sEVs function, at least in part through controlling the expression of bioactive miRNAs in sEVs.

MicroRNAs: Important Regulatory Molecules in Acute Lung Injury/Acute Respiratory Distress Syndrome

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is an overactivated inflammatory response caused by direct or indirect injuries that destroy lung parenchymal cells and dramatically reduce lung function. Although some research progress has been made in recent years, the pathogenesis of ALI/ARDS remains unclear due to its heterogeneity and etiology. MicroRNAs (miRNAs), a type of small noncoding RNA, play a vital role in various diseases. In ALI/ARDS, miRNAs can regulate inflammatory and immune responses by targeting specific molecules. Regulation of miRNA expression can reduce damage and promote the recovery of ALI/ARDS. Consequently, miRNAs are considered as potential diagnostic indicators and therapeutic targets of ALI/ARDS. Given that inflammation plays an important role in the pathogenesis of ALI/ARDS, we review the miRNAs involved in the inflammatory process of ALI/ARDS to provide new ideas for the pathogenesis, clinical diagnosis, and treatment of ALI/ARDS.

PTEN expression in human cumulus cells is associated with embryo development competence

Embryo quality determines the success of in vitro fertilization and embryo transfer (IVF-ET) treatment. Biomarkers for the evaluation of embryo quality have some limitations. Apoptosis in cumulus cells (CCs) is important for ovarian function. PTEN (phosphatase and tensin homolog) is a well known tumour suppressor gene that functions as a mediator of apoptosis and is crucial for mammalian reproduction. In the present study, we analyzed the expression level of PTEN in human CCs and aimed to investigate its association with embryo developmental competence in IVF treatment cycles. The PTEN mRNA level in CCs was measured using real-time fluorescence quantitative PCR. The association of the differential expression of PTEN with embryo quality was analyzed. Our data showed that PTEN mRNA levels were significantly decreased in CCs surrounding mature oocytes compared with immature oocytes. Similar changes were found in the analysis of fertilization and blastocyst formation. The speculation that the measurement of PTEN mRNA levels in human CCs would provide a useful tool for selecting oocytes with greater chances to implant into the uterus needs to be further verified through single-embryo transfer in the future. The proapoptotic mechanism of PTEN in human reproduction needs to be further studied.

Extracellular vesicle-mediated cellular crosstalk in lung repair, remodelling and regeneration

The unperturbed lung is highly quiescent, with a remarkably low level of cell turnover. However, once damaged, the lung shows an extensive regenerative capacity, with resident progenitor cell populations re-entering the cell cycle and differentiating to promote repair. This quick and dramatic repair response requires interactions among more than 40 different cell lineages in the lung, and defects in any of these processes can lead to various lung pathologies. Understanding the mechanisms of interaction in lung injury, repair and regeneration thus has considerable practical and therapeutic implications. Moreover, therapeutic strategies for replacing lung progenitor cells and their progeny through cell therapy have gained increasing attention. In the last decade, extracellular vesicles (EVs), including exosomes, have been recognised as paracrine mediators through the transfer of biological cargo. Recent work has revealed that EVs are involved in lung homeostasis and diseases. In addition, EVs derived from specific cells or tissues have proven to be a promising cell-free modality for the treatment of lung diseases. This review highlights the EV-mediated cellular crosstalk that regulates lung homeostasis and discusses the potential of EV therapeutics for lung regenerative medicine.

Healthy Serum-Derived Exosomes Improve Neurological Outcomes and Protect Blood–Brain Barrier by Inhibiting Endothelial Cell Apoptosis and Reversing Autophagy-Mediated Tight Junction Protein Reduction in Rat Stroke Model

Blood–brain barrier (BBB) dysfunction causing edema and hemorrhagic transformation is one of the pathophysiological characteristics of stroke. Protection of BBB integrity has shown great potential in improving stroke outcome. Here, we assessed the efficacy of exosomes extracted from healthy rat serum in protection against ischemic stroke in vivo and in vitro. Exosomes were isolated by gradient centrifugation and ultracentrifugation and exosomes were characterized by transmission electron microscopy (TEM) and nanoparticle tracking video microscope. Exosomes were applied to middle cerebral artery occlusion (MCAO) rats or brain microvascular endothelial cell line (bEnd.3) subjected to oxygen-glucose deprivation (OGD) injury. Serum-derived exosomes were injected intravenously into adult male rats 2 h after transient MCAO. Infarct volume and gross cognitive function were assessed 24 h after reperfusion. Poststroke rats treated with serum-derived exosomes exhibited significantly reduced infarct volumes and enhanced neurological function. Apoptosis was assessed via terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL) staining and the expression of B-cell lymphoma-2 (Bcl-2), Bax, and cleaved caspase-3 24 h after injury. Our data showed that serum exosomes treatment strikingly decreased TUNEL⁺ cells in the striatum, enhanced the ratio of Bcl-2 to Bax, and inhibited cleaved caspase-3 production in MCAO rats and OGD/reoxygenation insulted bEnd.3 cells. Under the consistent treatment, the expression of microtubule-associated protein 1 light chain 3B-II (LC3B-II), LC3B-I, and Sequestosome-1 (SQSTM1)/p62 was detected by Western blotting. Autolysosomes were observed via TEM. We found that serum exosomes reversed the ratio of LC3B-II to LC3B-I, prevented SQSTM1/p62 degradation, autolysosome formation, and autophagic flux. Together, these results indicated that exosomes isolated from healthy serum provided neuroprotection against experimental stroke partially via inhibition of endothelial cell apoptosis and autophagy-mediated BBB breakdown. Intravenous serum-derived exosome treatment may, therefore, provide a novel clinical therapeutic strategy for ischemic stroke.

Bone marrow mesenchymal stem cell-derived exosomal miR-34c-5p ameliorates RIF by inhibiting the core fucosylation of multiple proteins

Renal interstitial fibrosis (RIF) is an incurable pathological lesion in chronic kidney diseases. Pericyte activation is the major pathological characteristic of RIF. Fibroblast and macrophage activation are also involved in RIF. Studies have revealed that core fucosylation (CF), an important post-translational modification of proteins, plays a key role in pericyte activation and RIF by regulating multiple profibrotic signaling pathways as a hub-like target. Here, we reveal that mesenchymal stem cell (MSC)-derived exosomes reside specifically in the injured kidney and deliver microRNA (miR)-34c-5p to reduce cellular activation and RIF by inhibiting CF. Furthermore, we showed that the CD81-epidermal growth factor receptor (EGFR) ligand-receptor complex aids the entry of exosomal miR-34c-5p into pericytes, fibroblasts, and macrophages. Altogether, our findings reveal a novel role of MSC-derived exosomes in inhibiting multicellular activation via CF and provide a potential intervention strategy for renal fibrosis.

Exosomes-mediated phenotypic switch of macrophages in the immune microenvironment after spinal cord injury

Although accumulating evidence indicated that modulating macrophage polarization could ameliorate the immune microenvironment and facilitate the repair of spinal cord injury (SCI), the underlying mechanism of macrophage phenotypic switch is still poorly understood. Exosomes (Exos), a potential tool of cell-to-cell communication, may play important roles in cell reprogramming. Herein, we investigated the roles of macrophages-derived exosomes played for macrophage polarization in the SCI immune microenvironment. In this study, we found the fraction of M2 macrophages was markedly decreased after SCI. Moreover, the M2 macrophages-derived exosomes could increase the percentage of M2 macrophages, decrease that of M1 macrophages while the M1 macrophages-derived exosomes acted oppositely. According to the results of in silico analyses and molecular experiments verification, this phenotypic switch might be mediated by the exosomal miRNA-mRNA network, in which the miR-23a-3p/PTEN/PI3K/AKT axis might play an important role. In conclusion, our study suggests macrophage polarization that regulated by various interventions might be mediated by their own exosomes at last. Moreover, M2 macrophages-derived exosomes could promote M2 macrophage polarization via the potential miRNA-mRNA network. Considering its potential of modulating polarization, M2 macrophages-derived exosomes may be a promising therapeutic agent for SCI repair.

Roles and mechanisms of exosomal non-coding RNAs in human health and diseases

Exosomes play a role as mediators of cell-to-cell communication, thus exhibiting pleiotropic activities to homeostasis regulation. Exosomal non-coding RNAs (ncRNAs), mainly microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and circular RNAs (circRNAs), are closely related to a variety of biological and functional aspects of human health. When the exosomal ncRNAs undergo tissue-specific changes due to diverse internal or external disorders, they can cause tissue dysfunction, aging, and diseases. In this review, we comprehensively discuss the underlying regulatory mechanisms of exosomes in human diseases. In addition, we explore the current knowledge on the roles of exosomal miRNAs, lncRNAs, and circRNAs in human health and diseases, including cancers, metabolic diseases, neurodegenerative diseases, cardiovascular diseases, autoimmune diseases, and infectious diseases, to determine their potential implication in biomarker identification and therapeutic exploration.

Extracellular vesicles in acute respiratory distress syndrome: Recent developments from bench to bedside

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS), characterized by a large number of inflammatory cell aggregation and alveolar cell damage in pathophysiology, have extremely high morbidity and mortality in critically ill patients. In recent years, more and more studies have found that there are abundant extracellular vesicles (EVs) in animal models and patients with ALI/ARDS, and they play a critical role in the pathogenesis of lung injury. Clarifying the mechanisms of EVs in lung injury is of great significance in the diagnosis and treatment of ALI/ARDS. In this review, we will summarize the recent findings on the roles of EVs derived from different cells in ALI/ARDS, along with the formation, function, and related effects of EVs, and explore their potential clinical application for the diagnosis and treatment of ALI/ARDS.

MiRNA, a New Treatment Strategy for Pulmonary Fibrosis

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

miR-371b-5p promotes cell proliferation, migration and invasion in non-small cell lung cancer via SCAI

Objective: Multiple gene targets have been reported for treatment of non-small cell lung cancer (NSCLC), however, the accompanying genetic tolerance was reported increasingly. Therefore, it is important to find new biomarkers or therapeutic targets in treatment of NSCLC.

Methods: The expression levels of miR-371b-5p were detected by qRT-PCR in NSCLC tissues and cell lines. To evaluate the effect of miR-371b-5p on NSCLC progression, we first transfected the miR-371b-5p inhibitor for construction of the miR-371b-5p down-regulated cell model. Then the cell proliferation, migration, invasion and cell apoptosis were detected. In addition, the expression levels of adhesion factors were detected. The target gene of miR-371b-5p was identified by bioinformatics analysis, and rescue experiment was conducted to validate the effect of miR-371b-5p on proliferation, migration and invasion of NSCLC.

Results: Our findings revealed that the miR-371b-5p was overexpressed in NSCLC and could markedly promote the cell proliferation, migration and invasion. Expression levels of both intercellular adhesion molecule 1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were significantly down-regulated when treated by miR-371b-5p inhibitor. Moreover, dual-luciferase reporter assay showed that the miR-371b-5p targeted SCAI in regulation of cell proliferation, migration and invasion, and the expression of miR-371b-5p was negatively associated with SCAI in NSCLC tissues and cell lines. Rescue experiment revealed that the miR-371b-5p could rescue the effect of SCAI on cell proliferation, migration and invasion.

Conclusion: Our results suggest that the miR-371b-5p and SCAI may serve as novel prognostic biomarkers and therapeutic targets for NSCLC.

PTEN Expression in Human Granulosa Cells Is Associated with Ovarian Responses and Clinical Outcomes in IVF

The ovarian reserve determines the success of in vitro fertilization (IVF) and embryo transfer treatment. It predicts the ovarian response in controlled ovarian hyperstimulation cycles. Apoptosis in granulosa cells surrounding oocytes is important for ovarian function and has been closely associated with follicular atresia. PTEN (encoding phosphatase and tensin homolog) is a well-known tumor suppressor gene that functions as a mediator of apoptosis and is crucial for mammal reproduction. In the present study, we analyzed the expression level of PTEN in human granulosa cells and aimed to investigate its association with the ovarian response and clinical outcomes in IVF. Apoptosis in granulosa cells were analyzed using Annexin V-Allophycocyanin staining after PTEN short hairpin RNA lentivirus transfection. Real-time fluorescent quantitative PCR analysis showed that the PTEN transcript level was significantly higher in poor responders and significantly lower in high responders, compared with that in normal responders. However, PTEN expression in the pregnancy group decreased slightly, but not significantly, compared with that in the non-pregnancy group. The apoptosis rate of granulosa cells declined significantly after 24-h transfection of the PTEN-shRNA lentivirus. These results suggest a fundamental role of PTEN in the regulation of follicular development, and that it might be involved in the pathogenesis of follicular dysplasia and ovarian dysfunction.

BMSC-derived exosomes alleviate smoke inhalation lung injury through blockade of the HMGB1/NF-κB pathway

AIMS

To investigate the role of bone marrow mesenchymal stem cell (BMSC)-derived exosomes in smoke inhalation lung injury.

MAIN METHODS

In this study, we initially isolated exosomes from BMSCs and identified them by western blot and transmission electron microscopy. BMSC-derived exosomes were then used to treat in vitro and in vivo models of smoke inhalation lung injury. Pathologic alterations in lung tissue, the levels of inflammatory factors and apoptosis-related factors, and the expression of HMGB1 and NF-κB were determined to evaluate the therapeutic effect of BMSC-derived exosomes.

KEY FINDINGS

We found that BMSC-derived exosomes could alleviate the injury caused by smoke inhalation. Smoke inhalation increased the levels of inflammatory factors and apoptosis-related factors and the expression of HMGB1 and NF-κB, and these increases were reversed by BMSC-derived exosomes. HMGB1 overexpression abrogated the exosome-induced decreases in inflammatory factors, apoptosis-related factors and NF-κB.

SIGNIFICANCE

Collectively, these results indicate that BMSC-derived exosomes can effectively alleviate smoke inhalation lung injury by inhibiting the HMGB1/NF-κB pathway, suggesting that exosome, a noncellular therapy, is a potential therapeutic strategy for inhalation lung injury.

Stem cell derived exosomes-based therapy for acute lung injury and acute respiratory distress syndrome: A novel therapeutic strategy

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a common critical disease which can be caused by multiple pathological factors in clinic. However, feasible and effective treatment strategies of ALI/ARDS are limited. At present, the beneficial effect of stem cells (SCs)-based therapeutic strategies for ALI/ARDS can be attributed to paracrine. Exosomes, as a paracrine product, are regarded as a critical regulatory mediator. Furthermore, substantial evidence has indicated that exosomes from SCs can transmit bioactive components including genetic material and protein to the recipient cells and provide a protective effect. The protective role is played through a series of process including inflammation modulation, the reconstruction of alveolar epithelium and endothelium, and pulmonary fibrosis prevention. Therefore, SCs derived exosomes have the potential to be used for therapeutic strategies for ALI/ARDS. In this review, we discuss the present understanding of SCs derived exosomes related to ALI/ARDS and provide insights for developing a cell-free strategy for treating ALI/ARDS.

Exosomal miR-103a-3p ameliorates lipopolysaccharide-induced immune response in BEAS-2B cells via NF-κB pathway by targeting transducin β-like 1X related protein 1

Abnormal immune response contributes to pathophysiology of pneumonia and is recognized as a main factor for high incidence rate in children. The association between exosomes and inflammation has been reported in diverse cell types and diseases. The current study focuses on exploring the effects of exosomal miR-103a-3p on lipopolysaccharide (LPS)-induced inflammation, and investigates the underlying mechanisms. We proved that miR-103a-3p was lowly expressed in blood samples of pneumonia patients and LPS-induced lung cells, and overexpression of miR-103a-3p weaken the LPS-induced inflammation. Using luciferase reporter assay and immunoprecipitation assay, we demonstrated that miR-103a-3p directly binds to a specific region of transducin β-like 1X related protein 1 (TBL1XR1), mediating the NF-κB signalling pathway, thus regulating immune response. Taken together, our data revealed that miR-103a-3p functions as an anti-inflammatory gene in childhood pneumonia and can be applied as therapeutic targets for the treatment of childhood pneumonia in the future.

Lung-derived exosomes in phosgene-induced acute lung injury regulate the functions of mesenchymal stem cells partially via miR-28-5p

Accidental phosgene exposure can result in acute lung injury (ALI). Mesenchymal stem cells (MSCs) have been found to alleviate phosgene-induced ALI. However, the mechanism of MSCs underlying such protective effect remains largely unexplored. Exosomes, important components of microenvironment, are closely associated with intercellular information transfer. In the present study, we isolated lung exosomes in rats after phosgene exposure by ultracentrifugation and explored their effects on MSCs in vitro. ALI exosomes were elliptical in shape and 50-200 nm in size. ALI exosomes could promote proliferation and migration of MSCs. Moreover, ALI exosomes increased the secretion of IL-10, leading to enhanced immunoregulatory properties of MSCs. The paracrine factors, VEGF, HGF, LL-37 and Ang-1, were also augmented by ALI exosomes. However, ALI exosomes had no effect on differentiation of MSCs towards lung alveolar cells. To identify the effective miRNAs in ALI exosomes, we performed miRNA profile analysis. MiR-28-5p was considered as a possible effective molecule. We further studied the effect of miR-28-5p on MSCs. MiR-28-5p mimic promoted proliferation, migration, immunomodulation of MSCs. MiR-28-5p mimic promoted the paracrine of VEGF, HGF, LL-37 and Ang-1. Besides, we explored molecular mechanism of miR-28-5p in MSCs. PI3K/Akt signaling pathway was found significantly augmented by miR-28-5p mimic, indicating the activation in this process. Taken together, our findings could help identify the effects of lung-derived exosomes on MSCs, and the effective molecule in exosomes, miR-28-5p, activated MSCs through PI3K/Akt signaling pathway.

Long noncoding RNA AC114812.8 promotes the progression of bladder cancer through miR-371b-5p/FUT4 axis

Bladder cancer (BC) brings a heavy burden to afflicted patients worldwide. In order to find new diagnostic markers and therapeutic targets for this disease, we investigated the role of a novel lncRNA, AC114812.8, in bladder cancer progression. Clone formation and CCK-8 assays were used to detect the proliferative capacity of the cells, and the transwell assay was used to explore their invasion and migration abilities. Wound healing experiments were also used to detect cell migration. Luciferase reporter assays were used to investigate the interactions between lncRNA, target gene and miRNA. The expression of FUT4 and marker genes related to epithelial-mesenchymal transition was explored through western blot analysis. Our findings revealed that AC114812.8 was significantly upregulated in BC and could markedly facilitate the proliferation, migration, and invasion of bladder cancer cells both in vitro and in vivo. Furthermore, duel-luciferase reporter assay revealed that AC114812.8 could regulate the FUT4 expression level by sponging miR-371b-5p to facilitate BC progression. We detected the levels of EMT-related biomarkers in AC114812.8-overexpressing BC cells by western blot analysis and found that AC114812.8 could promote EMT process. Rescue experiments showed that miR-371b-5p could rescue the effect of AC114812.8 on proliferation and metastasis of BC. Our results suggest that AC114812.8 could be a novel prognostic biomarker and therapeutic target for bladder cancer.

miR-20a-5p regulates pulmonary surfactant gene expression in alveolar type II cells

MicroRNA (miRNA) critically controls gene expression in many biological processes, including lung growth and pulmonary surfactant biosynthesis. The present study was conducted to investigate whether miR‐20a‐5p had such regulatory functions on alveolar type II (AT‐II) cells. To accomplish this, miR‐20a‐5p–overexpressed and miR‐20a‐5p–inhibited adenoviral vectors were constructed and transfected into cultured AT‐II cells that were isolated from rat foetal lungs of 19 days' gestation. Transfection efficiency was confirmed by observing the fluorescence of green fluorescent protein (GFP) carried by the viral vector, whereas miR‐20a‐5p levels were verified by real‐time PCR. The CCK‐8 assay was used to compare the proliferation ability of AT‐II cells that had over‐ or underexpressed miR‐20a‐5p. The expression of surfactant‐associated proteins (SPs) and phosphatase and tensin homolog (PTEN) was measured by real‐time PCR and Western blotting. In AT‐II cells, transfection resulted in over‐ or under‐regulation of miR‐20a‐5p. While overexpression of miR‐20a‐5p promoted pulmonary surfactant gene expression, its underexpression inhibited it. Consistent with its role in negatively regulating the pulmonary surfactant gene, an opposite pattern was observed for miR‐20a‐5p regulation of PTEN. As a result, when miR‐20a‐5p was rendered overexpressed, PTEN was down‐regulated. By contrast, when miR‐20a‐5p was underexpressed, PTEN was up‐regulated. Neither overexpression nor underexpression of miR‐20a‐5p altered the cell proliferation. miR‐20a‐5p plays no role in proliferation of foetal AT‐II cells but is a critical regulator of surfactant gene expression. The latter appears to be achieved through a regulatory process that implicates expression of PTEN.

Cancer cell-derived exosomes promote cell proliferation and inhibit cell apoptosis of both normal lung fibroblasts and non-small cell lung cancer cell through delivering alpha-smooth muscle actin

This study aimed to investigate the effect of non-small cell lung cancer (NSCLC) cell-derived exosome on cell proliferation and apoptosis in normal lung fibroblast cells and NSCLC cells, and whether it regulates cell functions through delivering alpha-smooth muscle actin (ASMA). NSCLC exosomes were extracted from A549 cells, then cocultured with normal lung fibroblasts (HLF1 cells) and NSCLC cells (A549 cells). Blank ShRNA and ASMA ShRNA plasmids were transferred into HLF1 cells/A549 cells with or without NSCLC exosomes, which were divided into 4 groups accordingly: Negative control (NC) group, SH group, Exosome group and Exosome+SH group. Western blot, immunofluorescence, qPCR, CCK-8 and AV/PI were used to detect protein level, gene expression, cell proliferation and cell apoptosis, respectively. In HLF1 cells, cell proliferation was enhanced while cell apoptosis rate was inhibited in Exosome group compared with NC group; and cell proliferation was attenuated while cell apoptosis rate was raised in Exosome+SH group than Exosome group in rescue experiment; the expressions of apoptotic markers C-caspase3 and Bcl-2 also revealed the same trends. Additionally, in A549 cells, cell proliferation was also increased while cell apoptosis was inhibited in Exosome group compared with NC group; and cell proliferation was reduced while cell apoptosis rate was elevated in Exosome+SH group than Exosome group in rescue experiment. In conclusion, NSCLC derived exosomes promote cell proliferation and inhibit cell apoptosis in both normal lung fibroblasts and NSCLC cells by delivering ASMA.

miR‑371b‑5p inhibits endothelial cell apoptosis in monocrotaline‑induced pulmonary arterial hypertension via PTEN/PI3K/Akt signaling pathways

Pulmonary arterial hypertension (PAH) is a clinical hemodynamic syndrome. It is characterized by elevated PA pressure and pulmonary vascular resistance. In the present study, the role of microRNA (miRNA/miR)-371b-5p in monocrotaline-induced PAH and the underlying mechanisms were investigated. In a monocrotaline-induced PAH rat model, gene chip and reverse transcription-quantitative polymerase chain reaction were employed to measure miRNA expression levels. The results revealed that miR-371b-5p was downregulated in PAH rats compared with the control group. In addition, in vitro results demonstrated that an miR-371b-5p inhibitor reduced miR-371b-5p expression levels, increased apoptosis and reduced proliferation of pulmonary arterial endothelial cells (PAECs) in rats with monocrotaline-induced PAH. Furthermore, inhibition of miR-371b-5p induced phosphatase and tensin homolog (PTEN) protein expression and suppressed that of phosphoinositide 3-kinase (PI3K) and phosphorylated (p)-Akt in the PAECs. In addition, VO-OHpic, a PTEN inhibitor, reduced the protein expression levels of PTEN in the PAECs and inhibited the effects of anti-miR-371b-5p on cell apoptosis. In addition, LY294002, a PI3K inhibitor, reduced the PI3K and p-Akt protein expression in the PAECs and reversed the effects of miR-371b-5p overexpression on the apoptosis of PAECs in rats with monocrotaline-induced PAH. Collectively, the results of the present study indicate that, in this animal model of PAH, miR-371b-5p inhibits apoptosis of PAECs via PTEN/PI3K/Akt signaling pathways.

Modulation of miRNAs by Vitamin C in Human Bone Marrow Stromal Cells

MicroRNAs (miRNAs) are small (18–25 nucleotides), noncoding RNAs that have been identified as potential regulators of bone marrow stromal cell (BMSC) proliferation, differentiation, and musculoskeletal development. Vitamin C is known to play a vital role in such types of biological processes through various different mechanisms by altering mRNA expression. We hypothesized that vitamin C mediates these biological processes partially through miRNA regulation. We performed global miRNA expression analysis on human BMSCs following vitamin C treatment using microarrays containing human precursor and mature miRNA probes. Bioinformatics analyses were performed on differentially expressed miRNAs to identify novel target genes and signaling pathways. Our bioinformatics analysis suggested that the miRNAs may regulate multiple stem cell-specific signaling pathways such as cell adhesion molecules (CAMs), fatty acid biosynthesis and hormone signaling pathways. Furthermore, our analysis predicted novel stem cell proliferation and differentiation gene targets. The findings of the present study demonstrate that vitamin C can have positive effects on BMSCs in part by regulating miRNA expression.