Emerging role of extracellular vesicles in lung injury and inflammation

Oncoprotein-induced transcript 3 protein-enriched extracellular vesicles promotes NLRP3 ubiquitination to alleviate acute lung injury after cardiac surgery

Acute lung injury (ALI) including acute respiratory distress syndrome (ARDS) is a major complication and increase the mortality of patients with cardiac surgery. We previously found that the protein cargoes enriched in circulating extracellular vesicles (EVs) are closely associated with cardiopulmonary disease. We aimed to evaluate the implication of EVs on cardiac surgery-associated ALI/ARDS. The correlations between "oncoprotein-induced transcript 3 protein (OIT3) positive" circulating EVs and postoperative ARDS were assessed. The effects of OIT3-overexpressed EVs on the cardiopulmonary bypass (CPB) -induced ALI in vivo and inflammation of human bronchial epithelial cells (BEAS-2B) were detected. OIT3 enriched in circulating EVs is reduced after cardiac surgery with CPB, especially with postoperative ARDS. The "OIT3 positive" EVs negatively correlate with lung edema, hypoxemia and CPB time. The OIT3-overexpressed EVs can be absorbed by pulmonary epithelial cells and OIT3 transferred by EVs triggered K48- and K63-linked polyubiquitination to inactivate NOD-like receptor protein 3 (NLRP3) inflammasome, and restrains pro-inflammatory cytokines releasing and immune cells infiltration in lung tissues, contributing to the alleviation of CPB-induced ALI. Overexpression of OIT3 in human bronchial epithelial cells have similar results. OIT3 promotes the E3 ligase Cbl proto-oncogene B associated with NLRP3 to induce the ubiquitination of NLRP3. Immunofluorescence tests reveal that OIT3 is reduced in the generation from the liver sinusoids endothelial cells (LSECs) and secretion in liver-derived EVs after CPB. In conclusion, OIT3 enriched in EVs is a promising biomarker of postoperative ARDS and a therapeutic target for ALI after cardiac surgery.

Hybrid biomineralized nanovesicles to enhance inflamed lung biodistribution and reduce side effect of glucocorticoid for ARDS therapy

Acute respiratory distress syndrome (ARDS) is a critical illness characterized by severe lung inflammation. Improving the delivery efficiency and achieving the controlled release of anti-inflammatory drugs at the lung inflammatory site are major challenges in ARDS therapy. Taking advantage of the increased pulmonary vascular permeability and a slightly acidic-inflammatory microenvironment, pH-responsive mineralized nanoparticles based on dexamethasone sodium phosphate (DSP) and Ca2+ were constructed. By further biomimetic modification with M2 macrophage membranes, hybrid mineralized nanovesicles (MM@LCaP) were designed to possess immunomodulatory ability from the membranes and preserve the pH-sensitivity from core nanoparticles for responsive drug release under acidic inflammatory conditions. Compared with healthy mice, the lung/liver accumulation of MM@LCaP in inflammatory mice was increased by around 5.5 times at 48 h after intravenous injection. MM@LCaP promoted the polarization of anti-inflammatory macrophages, calmed inflammatory cytokines, and exhibited a comprehensive therapeutic outcome. Moreover, MM@LCaP improved the safety profile of glucocorticoids. Taken together, the hybrid mineralized nanovesicles-based drug delivery strategy may offer promising ideas for enhancing the efficacy and reducing the toxicity of clinical drugs.

Light-induced Extracellular Vesicle Adsorption

The role of extracellular vesicles (EVs) in human health and disease has garnered considerable attention over the past two decades. However, while several types of EVs are known to interact dynamically with the extracellular matrix and there is great potential value in producing high-fidelity EV micropatterns, there are currently no label-free, high-resolution, and tunable platform technologies with this capability. We introduce Light-induced Extracellular Vesicle Adsorption (LEVA) as a powerful solution to rapidly advance the study of matrix- and surface-bound EVs and other particles. The versatility of LEVA is demonstrated using commercial GFP-EV standards, EVs from glioblastoma bioreactors, and E. coli outer membrane vesicles (OMVs), with the resulting patterns used for single EV characterization, single cell migration on migrasome-mimetic trails, and OMV-mediated neutrophil swarming. LEVA will enable rapid advancements in the study of matrix- and surface-bound EVs and other particles, and should encourage researchers from many disciplines to create novel diagnostic, biomimetic, immunoengineering, and therapeutic screening assays.

A large-scale production of mesenchymal stem cells and their exosomes for an efficient treatment against lung inflammation

Mesenchymal stem cells (MSCs) and their produced exosomes have demonstrated inherent capabilities of inflammation-guided targeting and inflammatory modulation, inspiring their potential applications as biologic agents for inflammatory treatments. However, the clinical applications of stem cell therapies are currently restricted by several challenges, and one of them is the mass production of stem cells to satisfy the therapeutic demands in the clinical bench. Herein, a production of human amnion-derived MSCs (hMSCs) at a scale of over 1 × 109 cells per batch was reported using a three-dimensional (3D) culture technology based on microcarriers coupled with a spinner bioreactor system. The present study revealed that this large-scale production technology improved the inflammation-guided migration and the inflammatory suppression of hMSCs, without altering their major properties as stem cells. Moreover, these large-scale produced hMSCs showed an efficient treatment against the lipopolysaccharide (LPS)-induced lung inflammation in mice models. Notably, exosomes collected from these large-scale produced hMSCs were observed to inherit the efficient inflammatory suppression capability of hMSCs. The present study showed that 3D culture technology using microcarriers coupled with a spinner bioreactor system can be a promising strategy for the large-scale expansion of hMSCs with improved anti-inflammation capability, as well as their secreted exosomes.

Exosome-mediated regulation of inflammatory pathway during respiratory viral disease

Viruses have developed many mechanisms by which they can stimulate or inhibit inflammation and cause various diseases, including viral respiratory diseases that kill many people every year. One of the mechanisms that viruses use to induce or inhibit inflammation is exosomes. Exosomes are small membrane nanovesicles (30-150 nm) released from cells that contain proteins, DNA, and coding and non-coding RNA species. They are a group of extracellular vesicles that cells can take up to produce and mediate communication. Intercellular effect exosomes can deliver a broad confine of biological molecules, containing nucleic acids, proteins, and lipids, to the target cell, where they can convey therapeutic or pathogenic consequences through the modulation of inflammation and immune processes. Recent research has shown that exosomes can deliver entire virus genomes or virions to distant target cells, then the delivered viruses can escape the immune system and infect cells. Adenoviruses, orthomyxoviruses, paramyxoviruses, respiratory syncytial viruses, picornaviruses, coronaviruses, and rhinoviruses are mostly related to respiratory diseases. In this article, we will first discuss the current knowledge of exosomes. We will learn about the relationship between exosomes and viral infections, and We mention the inflammations caused by viruses in the airways, the role of exosomes in them, and finally, we examine the relationship between the viruses as mentioned earlier, and the regulation of inflammatory pathways that play a role in causing the disease.

NOBILETIN AMELIORATES HEATSTROKE-INDUCED ACUTE LUNG INJURY BY INHIBITING FERROPTOSIS VIA P53/SLC7A11 PATHWAY

ABSTRACT

The molecular mechanism for nobiletin's protective effect against heatstroke-induced acute lung injury (HS-ALI) remains largely unknown. Previous research has demonstrated that ferroptosis is an important pathogenic event in HS-ALI. Nobiletin is a natural polymethoxylated flavonoid. Herein, we investigated the potential contribution of nobiletin to HS-ALI by inhibiting ferroptosis. Heat stress was used to induce HS-ALI in mice, and mouse lung epithelial-12 (MLE-12) cells were stimulated by heat stress in vitro . Nobiletin was administrated by gavage for 2 h before HS induction. Biochemical kits, immunofluorescence staining, and western blotting were performed on the markers of ferroptosis. Our results showed that nobiletin administration significantly attenuated HS-induced lung injury and ferroptosis. Moreover, nobiletin pretreatment significantly reversed HS-induced p53 upregulation in vivo and in vitro . Pretreatment with a p53 agonist, tenovin-6, partly abolished the protective effect of nobiletin in mice with HS-ALI. Meanwhile, p53 knockdown significantly increased GPX4 and SLC7A11 expression levels compared with the HS group in HS-induced MLE-12 cells. Subsequently, nobiletin ameliorated HS-induced MLE-12 cells ferroptosis by activating the SLC7A11/GPX4 pathway, whereas p53 overexpression effectively abolished the protective effect of nobiletin. Taken together, our findings reveal that nobiletin attenuates HS-ALI by inhibiting ferroptosis through the p53/SLC7A11 pathway, indicating it to be a potential therapeutic agent for HS-ALI prevention and treatment.

Diagnostic and therapeutic value of EVs in lungs diseases and inflammation

Extracellular vesicles (EVs) are membrane-derived messengers which have been playing an important role in the inflammation and pathogenesis of lung diseases. EVs contain varieties of DNA, RNA, and membrane receptors through which they work as a delivery system for bioactive molecules as well as intracellular communicators. EV signaling mediates tumor progression and metastasis. EVs are linked with many diseases and perform a diagnostic role in lung injury and inflammation so are used to diagnose the severity of diseases. EVs containing a variety of biomolecules communicate with the recipient cells during pathophysiological mechanisms thereby acquiring the attention of clinicians toward the diagnostic and therapeutic potential of EVs in different lung diseases. In this review, we summarize the role of EVs in inflammation with an emphasis on their potential as a novel candidate in the diagnostics and therapeutics of chronic obstructive pulmonary disease, asthma, and sarcoidosis.

Extracellular vesicles in bacterial and fungal diseases - Pathogenesis to diagnostic biomarkers

Intercellular communication among microbes plays an important role in disease exacerbation. Recent advances have described small vesicles, termed as "extracellular vesicles" (EVs), previously disregarded as "cellular dust" to be vital in the intracellular and intercellular communication in host-microbe interactions. These signals have been known to initiate host damage and transfer of a variety of cargo including proteins, lipid particles, DNA, mRNA, and miRNAs. Microbial EVs, referred to generally as "membrane vesicles" (MVs), play a key role in disease exacerbation suggesting their importance in pathogenicity. Host EVs help coordinate antimicrobial responses and prime the immune cells for pathogen attack. Hence EVs with their central role in microbe-host communication, may serve as important diagnostic biomarkers of microbial pathogenesis. In this review, we summarize current research regarding the roles of EVs as markers of microbial pathogenesis with specific focus on their interaction with host immune defence and their potential as diagnostic biomarkers in disease conditions.

Emodin Ameliorates Severe Acute Pancreatitis-Associated Acute Lung Injury in Rats by Modulating Exosome-Specific miRNA Expression Profiles

Background

Numerous preclinical investigations have exhibited the beneficial impact of emodin (EMO) on the management of severe acute pancreatitis (SAP)-associated acute lung injury (ALI). However, the potential of EMO to mitigate organ damage through the modulation of exosome (Exo)-specific miRNA expression profiles remains unclear.

Methods

The SAP rat model was established by retrograde injection of 5% sodium taurocholate into the pancreatic bile duct. Rats received intragastric administration of EMO at 2 h and 12 h post-modeling. Plasma and bronchoalveolar lavage fluid (BALF)-derived exosomes were isolated and purified from SAP rats treated with EMO. The therapeutic effects of these Exos in SAP rats were assessed using hematoxylin-eosin staining and measurement of inflammatory factor levels. MicroRNA (miRNA) sequencing was conducted on plasma and BALF-derived Exos, and rescue experiments were performed to investigate the function of NOVEL miR-29a-3p in the treatment of SAP using EMO.

Results

EMO exhibits ameliorative effects on pancreatic and lung injury and inflammation in rats with SAP. Plasma/BALF-derived Exos from EMO-treated SAP rats also have therapeutic effects on SAP rats. The miRNA expression profile of plasma and BALF-derived Exos in SAP rats underwent significant changes upon exposure to EMO. In particular, 34 differentially expressed miRNAs (DEmiRNAs) were identified when comparing BALF-SAP+EMO-Exo and BALF-SAP-Exo. 39 DEmiRNAs were identified when comparing plasma-SAP+EMO-Exo to plasma-SAP-Exo. We found that SAP rats treated with Exos derived from BALF exhibited a more potent therapeutic response than those treated with Exos derived from plasma. EMO may rely on NOVEL-rno-miR-29a-3p expression to prevent pulmonary injury in SAP rats.

Conclusion

The mechanism of action of EMO is observed to have a significant impact on the miRNA expression profile of Exos derived from plasma and BALF in SAP rats. NOVEL-rno-miR-29a-3p, which is specific to Exos, and is derived from BALF, may play a crucial role in the therapeutic efficacy of EMO.

Identification of genetic biomarkers, drug targets and agents for respiratory diseases utilising integrated bioinformatics approaches

Respiratory diseases (RD) are significant public health burdens and malignant diseases worldwide. However, the RD-related biological information and interconnection still need to be better understood. Thus, this study aims to detect common differential genes and potential hub genes (HubGs), emphasizing their actions, signaling pathways, regulatory biomarkers for diagnosing RD and candidate drugs for treating RD. In this paper we used integrated bioinformatics approaches (such as, gene ontology (GO) and KEGG pathway enrichment analysis, molecular docking, molecular dynamic simulation and network-based molecular interaction analysis). We discovered 73 common DEGs (CDEGs) and ten HubGs (ATAD2B, PPP1CB, FOXO1, AKT3, BCR, PDE4D, ITGB1, PCBP2, CD44 and SMARCA2). Several significant functions and signaling pathways were strongly related to RD. We recognized six transcription factor (TF) proteins (FOXC1, GATA2, FOXL1, YY1, POU2F2 and HINFP) and five microRNAs (hsa-mir-218-5p, hsa-mir-335-5p, hsa-mir-16-5p, hsa-mir-106b-5p and hsa-mir-15b-5p) as the important transcription and post-transcription regulators of RD. Ten HubGs and six major TF proteins were considered drug-specific receptors. Their binding energy analysis study was carried out with the 63 drug agents detected from network analysis. Finally, the five complexes (the PDE4D-benzo[a]pyrene, SMARCA2-benzo[a]pyrene, HINFP-benzo[a]pyrene, CD44-ketotifen and ATAD2B-ponatinib) were selected for RD based on their strong binding affinity scores and stable performance as the most probable repurposable protein-drug complexes. We believe our findings will give readers, wet-lab scientists, and pharmaceuticals a thorough grasp of the biology behind RD.

The elucidation of plasma lipidome profiles during severe influenza in a mouse model

Although influenza virus infection has been shown to affect lipid metabolism, details remain unknown. Therefore, we elucidated the kinetic lipid profiles of mice infected with different doses of influenza virus A/Puerto Rico/8/34 (H1N1) (PR8) by measuring multiple lipid molecular species using untargeted lipidomic analysis. C57BL/6 male mice were intranasally infected with PR8 virus at 50 or 500 plaque-forming units to cause sublethal or lethal influenza, respectively. Plasma and tissue samples were collected at 1, 3, and 6 days post-infection (dpi), and comprehensive lipidomic analysis was performed using high-performance liquid chromatography-linear trap quadrupole-Orbitrap mass spectrometry, as well as gene expression analyses. The most prominent feature of the lipid profile in lethally infected mice was the elevated plasma concentrations of phosphatidylethanolamines (PEs) containing polyunsaturated fatty acid (PUFA) at 3 dpi. Furthermore, the facilitation of PUFA-containing phospholipid production in the lungs, but not in the liver, was suggested by gene expression and lipidomic analysis of tissue samples. Given the increased plasma or serum levels of PUFA-containing PEs in patients with other viral infections, especially in severe cases, the elevation of these phospholipids in circulation could be a biomarker of infection and the severity of infectious diseases.

Beyond Macromolecules: Extracellular Vesicles as Regulators of Inflammatory Diseases

Inflammation is the defense mechanism of the immune system against harmful stimuli such as pathogens, toxic compounds, damaged cells, radiation, etc., and is characterized by tissue redness, swelling, heat generation, pain, and loss of tissue functions. Inflammation is essential in the recruitment of immune cells at the site of infection, which not only aids in the elimination of the cause, but also initiates the healing process. However, prolonged inflammation often brings about several chronic inflammatory disorders; hence, a balance between the pro- and anti-inflammatory responses is essential in order to eliminate the cause while producing the least damage to the host. A growing body of evidence indicates that extracellular vesicles (EVs) play a major role in cell-cell communication via the transfer of bioactive molecules in the form of proteins, lipids, DNA, RNAs, miRNAs, etc., between the cells. The present review provides a brief classification of the EVs followed by a detailed description of how EVs contribute to the pathogenesis of various inflammation-associated diseases and their implications as a therapeutic measure. The latter part of the review also highlights how EVs act as a bridging entity in blood coagulation disorders and associated inflammation. The findings illustrated in the present review may open a new therapeutic window to target EV-associated inflammatory responses, thereby minimizing the negative outcomes.

Engineered Extracellular Vesicles Derived from Dermal Fibroblasts Attenuate Inflammation in a Murine Model of Acute Lung Injury

Acute respiratory distress syndrome (ARDS) represents a significant burden to the healthcare system, with ≈200 000 cases diagnosed annually in the USA. ARDS patients suffer from severe refractory hypoxemia, alveolar-capillary barrier dysfunction, impaired surfactant function, and abnormal upregulation of inflammatory pathways that lead to intensive care unit admission, prolonged hospitalization, and increased disability-adjusted life years. Currently, there is no cure or FDA-approved therapy for ARDS. This work describes the implementation of engineered extracellular vesicle (eEV)-based nanocarriers for targeted nonviral delivery of anti-inflammatory payloads to the inflamed/injured lung. The results show the ability of surfactant protein A (SPA)-functionalized IL-4- and IL-10-loaded eEVs to promote intrapulmonary retention and reduce inflammation, both in vitro and in vivo. Significant attenuation is observed in tissue damage, proinflammatory cytokine secretion, macrophage activation, influx of protein-rich fluid, and neutrophil infiltration into the alveolar space as early as 6 h post-eEVs treatment. Additionally, metabolomics analyses show that eEV treatment causes significant changes in the metabolic profile of inflamed lungs, driving the secretion of key anti-inflammatory metabolites. Altogether, these results establish the potential of eEVs derived from dermal fibroblasts to reduce inflammation, tissue damage, and the prevalence/progression of injury during ARDS via nonviral delivery of anti-inflammatory genes/transcripts.

Advances in the Therapeutic Applications of Plant-Derived Exosomes in the Treatment of Inflammatory Diseases

Plant-derived exosomes (PLDEs) are small extracellular vesicles that encapsulate proteins, nucleic acids and lipids, and they are usually involved in intercellular communication and molecular transport in plants. PLDEs are widely used in the therapy of diseases due to their abundance and easy availability. The diverse roles of PLDEs, which include transportation of drugs, acting as biomarkers for diagnosis of diseases and their roles in different therapies, suggest that there is a need to fully understand all the mechanisms involved in order to provide the optimum conditions for their therapeutic use. This review summarizes the biogenesis, components and functions of PLDEs and focuses on their use as therapeutic agents in the treatment of inflammatory diseases. It also explores new ideas for novel approaches in which PLDEs could potentially help patients with inflammatory diseases in the future.

Potential of extracellular vesicles for early prediction of severity and potential risk stratification in critical inflammatory diseases

Some acute inflammatory diseases are often exacerbated during or after hospitalization, leading to some severe manifestations like systemic inflammatory response syndrome, multiple organ failure, and high mortality. Early clinical predictors of disease severity are urgently needed to optimize patient management for better prognosis. The existing clinical scoring system and laboratory tests cannot circumvent the problems of low sensitivity and limited specificity. Extracellular vesicles (EVs) are heterogeneous nanosecretory vesicles containing various biomolecules related to immune regulation, inflammation activation, and inflammation-related complications. This review provides an overview of EVs as inflammatory mediators, inflammatory signaling pathway regulators, promoters of inflammatory exacerbation, and markers of severity and prognosis. Currently, although relevant biomarkers are clinically available or are in the preclinical research stage, searching for new markers and detection methods is still warranted, as the problems of low sensitivity/specificity, cumbersome laboratory operation and high cost still plague clinicians. In-depth study of EVs might open a door in the search for novel predictors.

Label-free microfluidic cell sorting and detection for rapid blood analysis

Blood tests are considered as standard clinical procedures to screen for markers of diseases and health conditions. However, the complex cellular background (>99.9% RBCs) and biomolecular composition often pose significant technical challenges for accurate blood analysis. An emerging approach for point-of-care blood diagnostics is utilizing "label-free" microfluidic technologies that rely on intrinsic cell properties for blood fractionation and disease detection without any antibody binding. A growing body of clinical evidence has also reported that cellular dysfunction and their biophysical phenotypes are complementary to standard hematoanalyzer analysis (complete blood count) and can provide a more comprehensive health profiling. In this review, we will summarize recent advances in microfluidic label-free separation of different blood cell components including circulating tumor cells, leukocytes, platelets and nanoscale extracellular vesicles. Label-free single cell analysis of intrinsic cell morphology, spectrochemical properties, dielectric parameters and biophysical characteristics as novel blood-based biomarkers will also be presented. Next, we will highlight research efforts that combine label-free microfluidics with machine learning approaches to enhance detection sensitivity and specificity in clinical studies, as well as innovative microfluidic solutions which are capable of fully integrated and label-free blood cell sorting and analysis. Lastly, we will envisage the current challenges and future outlook of label-free microfluidics platforms for high throughput multi-dimensional blood cell analysis to identify non-traditional circulating biomarkers for clinical diagnostics.

Thrombotic storm in coronavirus disease 2019: from underlying mechanisms to its management

Introduction. Coronavirus disease 2019 (COVID-19) identified in December 2019 in Wuhan, China, is associated with high mortality rates worldwide.Hypothesis/Gap Statement. Thrombotic problems, such as coagulopathy, are common in COVID-19 patients. Despite anticoagulation, thrombosis is more common in patients in the intensive care unit and patients with more severe disease. Although the exact mechanisms of coagulopathy in COVID-19 patients are still unclear, studies showed that overactivation of the renin-angiotensin system (RAS), cytokine storm, endothelial damage, formation of neutrophil extracellular traps (NETs), and also extracellular vesicles (EVs) in response to COVID-19 induced inflammation can lead to systemic coagulation and thrombosis.Aim. The management of COVID-19 patients requires the use of basic and readily available laboratory markers, both on admission and during hospitalization. Because it is critical to understand the pathophysiology of COVID-19 induced coagulopathy and treatment strategies, in this review we attempt to explain the underlying mechanism of COVID-19 coagulopathy, its diagnosis, and the associated successful treatment strategies.Conclusion. The exact mechanisms behind COVID-19-related coagulopathy are still unclear, but several studies revealed some mechanisms. More research is needed to determine the best anticoagulant regimen and to study other therapeutic options.

Therapeutic use of calpeptin in COVID-19 infection

This perspective considers the benefits of the potential future use of the cell permeant calpain inhibitor, calpeptin, as a drug to treat severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. Recent work has reported calpeptin’s capacity to inhibit entry of the virus into cells. Elsewhere, several drugs, including calpeptin, were found to be able to inhibit extracellular vesicle (EV) biogenesis. Unsurprisingly, because of similarities between viral and EV release mechanisms, calpeptin has also been shown to inhibit viral egress. This approach, identifying calpeptin, through large-scale screening studies as a candidate drug to treat COVID-19, however, has not considered the longer term likely benefits of calpain inhibition, post-COVID-19. This perspective will reflect on the capacity of calpeptin for treating long COVID by inhibiting the overproduction of neutrophil extracellular traps potentially damaging lung cells and promoting clotting, together with limiting associated chronic inflammation, tissue damage and pulmonary fibrosis. It will also reflect on the tolerated and detrimental in vivo side-effects of calpain inhibition from various preclinical studies.

Role of extracellular vesicles in lung diseases

ABSTRACT

Extracellular vesicles (EVs) are anuclear particles composed of lipid bilayers that contain nucleic acids, proteins, lipids, and organelles. EVs act as an important mediator of cell-to-cell communication by transmitting biological signals or components, including lipids, proteins, messenger RNAs, DNA, microRNAs, organelles, etc, to nearby or distant target cells to activate and regulate the function and phenotype of target cells. Under physiological conditions, EVs play an essential role in maintaining the homeostasis of the pulmonary milieu but they can also be involved in promoting the pathogenesis and progression of various respiratory diseases including chronic obstructive pulmonary disease, asthma, acute lung injury/acute respiratory distress syndrome, idiopathic pulmonary fibrosis (IPF), and pulmonary artery hypertension. In addition, in multiple preclinical studies, EVs derived from mesenchymal stem cells (EVs) have shown promising therapeutic effects on reducing and repairing lung injuries. Furthermore, in recent years, researchers have explored different methods for modifying EVs or enhancing EVs-mediated drug delivery to produce more targeted and beneficial effects. This article will review the characteristics and biogenesis of EVs and their role in lung homeostasis and various acute and chronic lung diseases and the potential therapeutic application of EVs in the field of clinical medicine.

Impact of Air Pollution in Airway Diseases: Role of the Epithelial Cells (Cell Models and Biomarkers)

Biomedical research is multidisciplinary and often uses integrated approaches performing different experimental models with complementary functions. This approach is important to understand the pathogenetic mechanisms concerning the effects of environmental pollution on human health. The biological activity of the substances is investigated at least to three levels using molecular, cellular, and human tissue models. Each of these is able to give specific answers to experimental problems. A scientific approach, using biological methods (wet lab), cell cultures (cell lines or primary), isolated organs (three-dimensional cell cultures of primary epithelial cells), and animal organisms, including the human body, aimed to understand the effects of air pollution on the onset of diseases of the respiratory system. Biological methods are divided into three complementary models: in vitro, ex vivo, and in vivo. In vitro experiments do not require the use of whole organisms (in vivo study), while ex vivo experiments use isolated organs or parts of organs. The concept of complementarity and the informatic support are useful tools to organize, analyze, and interpret experimental data, with the aim of discussing scientific notions with objectivity and rationality in biology and medicine. In this scenario, the integrated and complementary use of different experimental models is important to obtain useful and global information that allows us to identify the effect of inhaled pollutants on the incidence of respiratory diseases in the exposed population. In this review, we focused our attention on the impact of air pollution in airway diseases with a rapid and descriptive analysis on the role of epithelium and on the experimental cell models useful to study the effect of toxicants on epithelial cells.

The emerging therapeutic potential of extracellular vesicles in trauma

Traumatic injury is a major cause of morbidity and mortality worldwide, despite significant advances in treatments. Most deaths occur either very early, through massive head trauma/CNS injury or exsanguination (despite advances in transfusion medicine), or later after injury often through multiple organ failure and secondary infection. Extracellular vesicles (EVs) are known to increase in the circulation after trauma and have been used to limited extent as diagnostic and prognostic markers. More intriguingly, EVs are now being investigated as both causes of pathologies post trauma, such as trauma-induced coagulopathy, and as potential treatments. In this review, we highlight what is currently known about the role and effects of EVs in various aspects of trauma, as well as exploring current literature from investigators who have begun to use EVs therapeutically to alter the physiology and pathology of traumatic insults. The potential effectiveness of using EVs therapeutically in trauma is supported by a large number of experimental studies, but there is still some way to go before we understand the complex effects of EVs in what is already a complex disease process.

microRNA-19b-3p-containing extracellular vesicles derived from macrophages promote the development of atherosclerosis by targeting JAZF1

Atherosclerosis has been regarded as a major contributor to cardiovascular disease. The role of extracellular vesicles (EVs) in the treatment of atherosclerosis has been increasingly reported. In this study, we set out to investigate the effect of macrophages‐derived EVs (M‐EVs) containing miR‐19b‐3p in the progression of atherosclerosis, with the involvement of JAZF1. Following isolation of EVs from macrophages, the M‐EVs were induced with ox‐low density lipoprotein (LDL) (ox‐LDL‐M‐EVs), and co‐cultured with vascular smooth muscle cells (VSMCs). RT‐qPCR and western blot assay were performed to determine the expression of miR‐19b‐3p and JAZF1 in M‐EVs and in VSMCs. Lentiviral infection was used to overexpress or knock down miR‐19b‐3p. EdU staining and scratch test were conducted to examine VSMC proliferation and migration. Dual‐luciferase gene reporter assay was performed to examine the relationship between miR‐19b‐3p and JAZF1. In order to explore the role of ox‐LDL‐M‐EVs carrying miR‐19b‐3p in atherosclerotic lesions in vivo, a mouse model of atherosclerosis was established through high‐fat diet induction. M‐EVs were internalized by VSMCs. VSMC migration and proliferation were promoted by ox‐LDL‐M‐EVs. miR‐19b‐3p displayed upregulation in ox‐LDL‐M‐EVs. miR‐19b‐3p was transferred by M‐EVs into VSMCs, thereby promoting VSMC migration and proliferation. mir‐19b‐3p targeted JAZF1 to decrease its expression in VSMCs. Atherosclerosis lesions were aggravated by ox‐LDL‐M‐EVs carrying miR‐19b‐3p in ApoE^−/− mice. Collectively, this study demonstrates that M‐EVs containing miR‐19b‐3p accelerate migration and promotion of VSMCs through targeting JAZF1, which promotes the development of atherosclerosis.

Extracellular Vesicles and Alveolar Epithelial-Capillary Barrier Disruption in Acute Respiratory Distress Syndrome: Pathophysiological Role and Therapeutic Potential

Extracellular vesicles (EVs) mediate intercellular communication by transferring genetic material, proteins and organelles between different cells types in both health and disease. Recent evidence suggests that these vesicles, more than simply diagnostic markers, are key mediators of the pathophysiology of acute respiratory distress syndrome (ARDS) and other lung diseases. In this review, we will discuss the contribution of EVs released by pulmonary structural cells (alveolar epithelial and endothelial cells) and immune cells in these diseases, with particular attention to their ability to modulate inflammation and alveolar-capillary barrier disruption, a hallmark of ARDS. EVs also offer a unique opportunity to develop new therapeutics for the treatment of ARDS. Evidences supporting the ability of stem cell-derived EVs to attenuate the lung injury and ongoing strategies to improve their therapeutic potential are also discussed.

Inflammatory alveolar macrophage-derived microvesicles damage lung epithelial cells and induce lung injury

Emerging evidence has demonstrated that several microvesicles (MVs) are secreted in bronchoalveolar lavage fluid (BALF) during the pathogenesis of acute lung injury/acute respiratory distress syndrome (ALI/ARDS). However, the impact of alveolar macrophage (AM)-derived MVs on epithelial cells and their in vivo effects on ALI/ARDS require further exploration. In this study, MVs were isolated from BALF of mice or mouse alveolar macrophage (MHS) cells by sequential centrifugation and then delivered to epithelial cells or mice. Enzyme-linked immunosorbent assay revealed that BALF-derived MVs (BALF-MVs) and MHS-derived MVs (AM-MVs) were rich in tumor necrosis factor-α (TNF-α) at the early stage of lung injury. In vitro, both inflammatory BALF-MVs and AM-MVs decreased the expression of α subunit of epithelial sodium channel (α-ENaC), γ-ENaC, and Na⁺,K⁺-ATPase α1 and β1 in lung epithelial cells. However, antibodies against TNF-α inhibited the effects of inflammatory AM-MVs in epithelial cells. In vivo, the inflammatory AM-MVs, delivered intratracheally to mice, impaired lung tissues and increased the injury score. They also resulted in decreased alveolar fluid clearance and increased lung wet weight/dry weight ratio. Furthermore, inflammatory AM-MVs downregulated the α-ENaC, γ-ENaC, and Na⁺,K⁺-ATPase α1 and β1 levels in lung tissues. According to our results, inflammatory AM-derived MVs may potentially contribute to lung injury and pulmonary edema, thereby indicating a potential novel therapeutic approach against ALI/ARDS based on AM-MVs.

Epithelial-Cell-Derived Extracellular Vesicles in Pathophysiology of Epithelial Injury and Repair in Chronic Rhinosinusitis: Connecting Immunology in Research Lab to Biomarkers in Clinics

Epithelial barrier disruption and failure of epithelial repair by aberrant epithelial-mesenchymal transition (EMT)-induced basal cells observed in nasal mucosa of chronic rhinosinusitis (CRS) are speculated to play important roles in disease pathophysiology. Microparticles (MPs) are a type of extracellular vesicle (EV) released by budding or shedding from the plasma membrane of activated or apoptotic cells. MPs are detected in nasal lavage fluids (NLFs) and are now receiving attention as potential biomarkers to evaluate the degree of activation of immune cells and injury of structural cells in nasal mucosa of subjects with sinus disease. There are three types of epithelial-cell-derived MPs, which are defined by the expression of different epithelial specific markers on their surface: EpCAM, E-cadherin, and integrin β6 (ITGB6). When these markers are on MPs that are also carrying canonical EMT/mesenchymal markers (Snail (SNAI1); Slug (SNAI2); alpha-smooth muscle actin (αSMA, ACTA2)) or pro- and anti-coagulant molecules (tissue factor (TF); tissue plasminogen activator (tPA); plasminogen activator inhibitor-1 (PAI-1)), they provide insight as to the roles of epithelial activation for EMT or regulation of coagulation in the underlying disease. In this review, we discuss the potential of epithelial MPs as research tools to evaluate status of nasal mucosae of CRS patients in the lab, as well as biomarkers for management and treatment of CRS in the clinic.

Emodin attenuates severe acute pancreatitis-associated acute lung injury by suppressing pancreatic exosome-mediated alveolar macrophage activation

Severe acute pancreatitis-associated acute lung injury (SAP-ALI) is a serious disease associated with high mortality. Emodin has been applied to alleviate SAP-ALI; however, the mechanism remains unclear. We report that the therapeutic role of emodin in attenuating SAP-ALI is partly dependent on an exosomal mechanism. SAP rats had increased levels of plasma exosomes with altered protein contents compared to the sham rats. These infused plasma exosomes tended to accumulate in the lungs and promoted the hyper-activation of alveolar macrophages and inflammatory damage. Conversely, emodin treatment decreased the plasma/pancreatic exosome levels in the SAP rats. Emodin-primed exosomes showed less pro-inflammatory effects in alveolar macrophages and lung tissues than SAP exosomes. In detail, emodin-primed exosomes suppressed the NF-κB pathway to reduce the activation of alveolar macrophage and ameliorate lung inflammation by regulating PPARγ pathway, while these effects were amplified/abolished by PPARγ agonist/antagonist. Blockage of pancreatic acinar cell exosome biogenesis also exhibited suppression of alveolar macrophage activation and reduction of lung inflammation. This study suggests a vital role of exosomes in participating inflammation-associated organ-injury, and indicates emodin can attenuate SAP-ALI by reducing the pancreatic exosome-mediated alveolar macrophage activation.

Exosome: Function and Application in Inflammatory Bone Diseases

In the skeletal system, inflammation is closely associated with many skeletal disorders, including periprosthetic osteolysis (bone loss around orthopedic implants), osteoporosis, and rheumatoid arthritis. These diseases, referred to as inflammatory bone diseases, are caused by various oxidative stress factors in the body, resulting in long-term chronic inflammatory processes and eventually causing disturbances in bone metabolism, increased osteoclast activity, and decreased osteoblast activity, thereby leading to osteolysis. Inflammatory bone diseases caused by nonbacterial factors include inflammation- and bone resorption-related processes. A growing number of studies show that exosomes play an essential role in developing and progressing inflammatory bone diseases. Mechanistically, exosomes are involved in the onset and progression of inflammatory bone disease and promote inflammatory osteolysis, but specific types of exosomes are also involved in inhibiting this process. Exosomal regulation of the NF-κB signaling pathway affects macrophage polarization and regulates inflammatory responses. The inflammatory response further causes alterations in cytokine and exosome secretion. These signals regulate osteoclast differentiation through the receptor activator of the nuclear factor-kappaB ligand pathway and affect osteoblast activity through the Wnt pathway and the transcription factor Runx2, thereby influencing bone metabolism. Overall, enhanced bone resorption dominates the overall mechanism, and over time, this imbalance leads to chronic osteolysis. Understanding the role of exosomes may provide new perspectives on their influence on bone metabolism in inflammatory bone diseases. At the same time, exosomes have a promising future in diagnosing and treating inflammatory bone disease due to their unique properties.

Diverse Effects of Exosomes on COVID-19: A Perspective of Progress From Transmission to Therapeutic Developments

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a new strain of coronavirus and the causative agent of the current global pandemic of coronavirus disease 2019 (COVID-19). There are currently no FDA-approved antiviral drugs for COVID-19 and there is an urgent need to develop treatment strategies that can effectively suppress SARS-CoV-2 infection. Numerous approaches have been researched so far, with one of them being the emerging exosome-based therapies. Exosomes are nano-sized, lipid bilayer-enclosed structures, share structural similarities with viruses secreted from all types of cells, including those lining the respiratory tract. Importantly, the interplay between exosomes and viruses could be potentially exploited for antiviral drug and vaccine development. Exosomes are produced by virus-infected cells and play crucial roles in mediating communication between infected and uninfected cells. SARS-CoV-2 modulates the production and composition of exosomes, and can exploit exosome formation, secretion, and release pathways to promote infection, transmission, and intercellular spread. Exosomes have been exploited for therapeutic benefits in patients afflicted with various diseases including COVID-19. Furthermore, the administration of exosomes loaded with immunomodulatory cargo in combination with antiviral drugs represents a novel intervention for the treatment of diseases such as COVID-19. In particular, exosomes derived from mesenchymal stem cells (MSCs) are used as cell-free therapeutic agents. Mesenchymal stem cell derived exosomes reduces the cytokine storm and reverse the inhibition of host anti-viral defenses associated with COVID-19 and also enhances mitochondrial function repair lung injuries. We discuss the role of exosomes in relation to transmission, infection, diagnosis, treatment, therapeutics, drug delivery, and vaccines, and present some future perspectives regarding their use for combating COVID-19.

The Potential Role of Extracellular Vesicles in COVID-19 Treatment: Opportunity and Challenge

SARS-CoV-2 infection has become an urgent public health concern worldwide, severely affecting our society and economy due to the long incubation time and high prevalence. People spare no effort on the rapid development of vaccine and treatment all over the world. Amongst the numerous ways of tackling this pandemic, some approaches using extracellular vesicles (EVs) are emerging. In this review, we summarize current prevalence and pathogenesis of COVID-19, involving the combination of SARS-CoV-2 and virus receptor ACE2, endothelial dysfunction and micro thrombosis, together with cytokine storm. We also discuss the ongoing EVs-based strategies for the treatment of COVID-19, including mesenchymal stem cell (MSC)-EVs, drug-EVs, vaccine-EVs, platelet-EVs, and others. This manuscript provides the foundation for the development of targeted drugs and vaccines for SARS-CoV-2 infections.

Application of biomaterials in periodontal tissue repair and reconstruction in the presence of inflammation under periodontitis through the foreign body response: Recent progress and perspectives

Periodontitis would cause dental tissue damage locally. Biomaterials substantially affect the surrounding immune microenvironment through treatment-oriented local inflammatory remodeling in dental periodontitis. This remodeling process is conducive to wound healing and periodontal tissue regeneration. Recent progress in understanding the foreign body response (FBR) and immune regulation, including cell heterogeneity, and cell-cell and cell-material interactions, has provided new insights into the design criteria for biomaterials applied in treatment of periodontitis. This review discusses recent progress and perspectives in the immune regulation effects of biomaterials to augment or reconstruct soft and hard tissue in an inflammatory microenvironment of periodontitis.

Efficacy of mesenchymal stromal cells and cellular products in improvement of symptoms for COVID-19 and similar lung diseases

At the end of 2019, respiratory coronavirus diseases 2019 (COVID-19) appeared and spread rapidly in the world. Besides several mutations, the outcome of this pandemic was the death up to 15% of hospitalized patients. Mesenchymal stromal cell therapy as a therapeutic strategy seemed successful in treatment of several diseases. Not only mesenchymal stromal cells of several tissues, but also their secreted extracellular vesicles and even secretome indicated beneficial therapeutic function. All of these three options were studied for treatment of COVID-19 as well as those respiratory diseases that have similar symptom. Fortunately, most of the outcomes were promising and optimistic. In this paper, we review in-vivo and clinical studies which have been used different sources of mesenchymal stromal cell, secreted extracellular vesicles, and secretome to improve and treat symptoms of COVID-19 and similar lung diseases.

Hepatic stellate cell-derived exosomes modulate macrophage inflammatory response

BACKGROUND

Hepatic stellate cell (HSC) differentiation/activation is central to liver fibrosis and is innately linked to the immune response to liver injury. Exosomes (EXOs) are important means of communication between cell populations. This study sought to characterize EXO release from HSCs and the effect of HSC-EXOs on macrophage cytokine release/function.

METHODS

Liver from a rat fibrosis model was analyzed for EXO expression and localization. Quiescent and culture-activated rat and mouse HSCs and activated human HSCs were analyzed for microRNA expression. Mouse, rat, and human HSCs were culture-activated and EXOs purified from culture medium prior to addition to macrophages, and interleukin-6 (IL-6) and tumor necrosis factor-α (TNFα) mRNA and protein measured. The effect of activated HSC-EXOs on macrophage migration was assayed.

RESULTS

Activation of rat HSCs led to increased EXO production in vivo, an effect mirrored by in vitro rat HSC culture-activation. Culture activation of mouse and rat HSCs led to altered EXO microRNA profiles, with a similar microRNA profile detected in activated human HSCs. Addition of activated HSC-EXOs to macrophages stimulated IL-6 and TNFα mRNA expression and protein secretion in mouse and human macrophages, but not for rat HSC-EXO-macrophages. Addition of human EXOs to macrophages stimulated migration, effects mirrored by the direct addition of rhIL-6 and rhTNFα.

CONCLUSIONS

HSC-EXOs associate with macrophages and stimulate cytokine synthesis-release and macrophage migration. Constructing a comprehensive understanding of EXO interactions between liver cell populations in the setting of inflammation/fibrosis increases the potential for developing new diagnostic/therapeutic approaches.

Extracellular Vesicles as Potential Therapeutics for Inflammatory Diseases

Extracellular vesicles (EV) deliver cargoes such as nucleic acids, proteins, and lipids between cells and serve as an intercellular communicator. As it is revealed that most of the functions associated to EVs are closely related to the immune response, the important role of EVs in inflammatory diseases is emerging. EVs can be functionalized through EV surface engineering and endow targeting moiety that allows for the target specificity for therapeutic applications in inflammatory diseases. Moreover, engineered EVs are considered as promising nanoparticles to develop personalized therapeutic carriers. In this review, we highlight the role of EVs in various inflammatory diseases, the application of EV as anti-inflammatory therapeutics, and the current state of the art in EV engineering techniques.

Role of biomaterials in the diagnosis, prevention, treatment, and study of corona virus disease 2019 (COVID-19)

Recently emerged novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and the resulting corona virus disease 2019 (COVID-19) led to urgent search for methods to prevent and treat COVID-19. Among important disciplines that were mobilized is the biomaterials science and engineering. Biomaterials offer a range of possibilities to develop disease models, protective, diagnostic, therapeutic, monitoring measures, and vaccines. Among the most important contributions made so far from this field are tissue engineering, organoids, and organ-on-a-chip systems, which have been the important frontiers in developing tissue models for viral infection studies. Also, due to low bioavailability and limited circulation time of conventional antiviral drugs, controlled and targeted drug delivery could be applied alternatively. Fortunately, at the time of writing this paper, we have two successful vaccines and new at-home detection platforms. In this paper, we aim to review recent advances of biomaterial-based platforms for protection, diagnosis, vaccination, therapeutics, and monitoring of SARS-CoV-2 and discuss challenges and possible future research directions in this field.

Role of extracellular vesicles in chronic lung disease

To explore the role of extracellular vesicles (EVs) in chronic lung diseases.

EVs are emerging as mediators of intercellular communication and possible diagnostic markers of disease. EVs harbour cargo molecules including RNA, lipids and proteins that they transfer to recipient cells. EVs are intercellular communicators within the lung microenvironment. Due to their disease-specific cargoes, EVs have the promise to be all-in-one complex multimodal biomarkers. EVs also have potential as drug carriers in chronic lung disease.

Descriptive discussion of key studies of EVs as contributors to disease pathology, as biomarkers and as potential therapies with a focus on chronic obstructive pulmonary disorder (COPD), cystic fibrosis (CF), asthma, idiopathic pulmonary fibrosis and lung cancer.

We provide a broad overview of the roles of EV in chronic respiratory disease. Recent advances in profiling EVs have shown their potential as biomarker candidates. Further studies have provided insight into their disease pathology, particularly in inflammatory processes across a spectrum of lung diseases. EVs are on the horizon as new modes of drug delivery and as therapies themselves in cell-based therapeutics.

EVs are relatively untapped sources of information in the clinic that can help further detail the full translational nature of chronic lung disorders.

Therapeutic Potential of Mesenchymal Stem Cells and Their Products in Lung Diseases-Intravenous Administration versus Inhalation

The number of publications studying the therapeutic use of stem cells has steadily increased since 2000. Compared to other applications, there has been little interest in the evaluation of mesenchymal stem cells (MSCs) and MSC-derived products (mostly extracellular vesicles) for the treatment of respiratory diseases. Due to the lack of efficient treatments for acute respiratory distress syndrome caused by infections with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the action of MSCs has also been studied. This review describes mode of action and use of MSCs and MSC-derived products in the treatment of lung diseases including the respective advantages and limitations of the products. Further, issues related to standardized production are addressed. Administration by inhalation of MSCs, compared to intravenous injection, could decrease cell damage by shear stress, eliminate the barrier to reach target cells in the alveoli, prevent thrombus formation in the pulmonary vasculature and retention in filter for extracorporeal membrane oxygenation. There is more feasible to deliver extracellular vesicles than MSCs with inhalers, offering the advantage of non-invasive and repeated administration by the patient. Major obstacles for comparison of results are heterogeneity of the products, differences in the treatment protocols and small study cohorts.

Regenerative Medicine in COVID-19 Treatment: Real Opportunities and Range of Promises

Novel coronavirus disease (COVID-19) has attracted much attention around the world due to its rapid transmission among humans and relatively high mortality rate. Studies are increasing to find the best therapeutic approach for the disease and its management. Regenerative medicine offers various cell-tissue therapeutics and related products, such as stem cell therapy, natural killer (NK) cell therapy, Chimeric antigen receptor (CAR) T cell therapy, exosomes, and tissue products. Interestingly, mesenchymal stem cells (MSCs) can reduce inflammatory symptoms and protect against cytokine storm, which critically contributes to the COVID-19 progression. Notably, having the potentials to exert cytotoxic effects on infected cells and induce interferon production probably make NK cells a candidate for COVID-19 cell therapy. Besides, exosomes are one of the crucial products of cells that can exert therapeutic effects through the induction of immune responses and neutralizing antibody titers. The paper aims to briefly consider current options for COVID-19 therapy to show that there is no specific cure for COVID-19, and then assess the real opportunities and range of promises regenerative medicine can provide for specific treatment of COVID-19. Graphical Abstract Therapeutic Potential of Regenerative Medicine against COVID19.

Intercellular Communication by Vascular Endothelial Cell-Derived Extracellular Vesicles and Their MicroRNAs in Respiratory Diseases

Respiratory diseases and their comorbidities, such as cardiovascular disease and muscle atrophy, have been increasing in the world. Extracellular vesicles (EVs), which include exosomes and microvesicles, are released from almost all cell types and play crucial roles in intercellular communication, both in the regulation of homeostasis and the pathogenesis of various diseases. Exosomes are of endosomal origin and range in size from 50 to 150 nm in diameter, while microvesicles are generated by the direct outward budding of the plasma membrane in size ranges of 100-2,000 nm in diameter. EVs can contain various proteins, metabolites, and nucleic acids, such as mRNA, non-coding RNA species, and DNA fragments. In addition, these nucleic acids in EVs can be functional in recipient cells through EV cargo. The endothelium is a distributed organ of considerable biological importance, and disrupted endothelial function is involved in the pathogenesis of respiratory diseases such as chronic obstructive pulmonary disease, pulmonary hypertension, and acute respiratory distress syndrome. Endothelial cell-derived EVs (EC-EVs) play crucial roles in both physiological and pathological conditions by traveling to distant sites through systemic circulation. This review summarizes the pathological roles of vascular microRNAs contained in EC-EVs in respiratory diseases, mainly focusing on chronic obstructive pulmonary disease, pulmonary hypertension, and acute respiratory distress syndrome. Furthermore, this review discusses the potential clinical usefulness of EC-EVs as therapeutic agents in respiratory diseases.

Human mesenchymal stromal cell source and culture conditions influence extracellular vesicle angiogenic and metabolic effects on human endothelial cells in vitro

BACKGROUND

Mesenchymal stem/stromal cell (MSC)-derived extracellular vesicles (EVs) are a possible cell-free alternative to MSCs because they retain the regenerative potential of MSCs, while still mitigating some of their limitations (such as the possible elicitation of host immune responses). The promotion and restoration of angiogenesis, however, is an important component in treating trauma-related injuries, and has not been fully explored with EVs. Herein, we describe the effects of monolayer adipose-derived EVs, spheroid adipose-derived EVs (SAd-EVs), monolayer bone marrow-derived EVs (MBM-EVs), and spheroid bone marrow-derived EVs (SBM-EVs) on human umbilical vein endothelial cell (HUVEC) tube formation and mitochondrial respiration.

METHODS

The successful isolation of EVs derived from adipose MSCs or bone marrow MSCs in monolayer or spheroid cultures was confirmed by NanoSight (particle size distribution) and Western blot (surface marker expression). The EV angiogenic potential was measured using a 24-hour HUVEC tube formation assay. The EV effects on HUVEC mitochondrial function were evaluated using the Seahorse respirometer machine.

RESULTS

The number of junctions, branches, and the average length of branches formed at 24 hours of tube formation were significantly affected by cell and culture type; overall adipose-derived EVs outperformed bone marrow-derived EVs, and spheroid-derived EVs outperformed monolayer-derived EVs. Additionally, adipose-derived EVs resulted in significantly increased HUVEC mitochondrial maximal respiration and adenosine triphosphate (ATP) production, while only MBM-EVs negatively impacted HUVEC proton leak.

CONCLUSION

Adipose-derived EVs promoted HUVEC tube formation significantly more than bone marrow-derived EVs, while also maximizing HUVEC mitochondria function. Results demonstrate that, as with MSC therapies, it is possible to tailor EV culture and production to optimize therapeutic potential.

LEVEL OF EVIDENCE

Basic or Foundational Research.

Extracellular Vesicles as Unique Signaling Messengers: Role in Lung Diseases

Extracellular vesicles (EVs) are lipid bilayer-enclosed extracellular particles carrying rich cargo such as proteins, lipids, and microRNAs with distinct characteristics of their parental cells. EVs are emerging as an important form of cellular communication with the ability to selectively deliver a kit of directional instructions to nearby or distant cells to modulate their functions and phenotypes. According to their biogenesis, EVs can be divided into two groups: those of endocytic origin are called exosomes and those derived from outward budding of the plasma membrane are called microvesicles (also known as ectosomes or microparticles). Under physiological conditions, EVs are actively involved in maintenance of pulmonary hemostasis. However, EVs can contribute to the pathogenesis of diseases such as chronic obstructive pulmonary disease, asthma, acute lung injury/acute respiratory distress syndrome, interstitial lung disease, and pulmonary arterial hypertension. EVs, especially those derived from mesenchymal/stromal stem cells, can also be beneficial and can curb the development of lung diseases. Novel technologies are continuously being developed to minimize the undesirable effects of EVs and also to engineer EVs so that they may have beneficial effects and can be used as therapeutic agents in lung diseases. © 2021 American Physiological Society. Compr Physiol 11:1351-1369, 2021.

Corrected Super-Resolution Microscopy Enables Nanoscale Imaging of Autofluorescent Lung Macrophages

Observing the cell surface and underlying cytoskeleton at nanoscale resolution using super-resolution microscopy has enabled many insights into cell signaling and function. However, the nanoscale dynamics of tissue-specific immune cells have been relatively little studied. Tissue macrophages, for example, are highly autofluorescent, severely limiting the utility of light microscopy. Here, we report a correction technique to remove autofluorescent noise from stochastic optical reconstruction microscopy (STORM) data sets. Simulations and analysis of experimental data identified a moving median filter as an accurate and robust correction technique, which is widely applicable across challenging biological samples. Here, we used this method to visualize lung macrophages activated through Fc receptors by antibody-coated glass slides. Accurate, nanoscale quantification of macrophage morphology revealed that activation induced the formation of cellular protrusions tipped with MHC class I protein. These data are consistent with a role for lung macrophage protrusions in antigen presentation. Moreover, the tetraspanin protein CD81, known to mark extracellular vesicles, appeared in ring-shaped structures (mean diameter 93 ± 50 nm) at the surface of activated lung macrophages. Thus, a moving median filter correction technique allowed us to quantitatively analyze extracellular secretions and membrane structure in tissue-derived immune cells.

Effects of mesenchymal stromal cell-conditioned media on measures of lung structure and function: a systematic review and meta-analysis of preclinical studies

BACKGROUND

Lung disease is a leading cause of morbidity and mortality. A breach in the lung alveolar-epithelial barrier and impairment in lung function are hallmarks of acute and chronic pulmonary illness. This review is part two of our previous work. In part 1, we demonstrated that CdM is as effective as MSCs in modulating inflammation. Herein, we investigated the effects of mesenchymal stromal cell (MSC)-conditioned media (CdM) on (i) lung architecture/function in animal models mimicking human lung disease, and (ii) performed a head-to-head comparison of CdM to MSCs.

METHODS

Adhering to the animal Systematic Review Centre for Laboratory animal Experimentation protocol, we conducted a search of English articles in five medical databases. Two independent investigators collected information regarding lung: alveolarization, vasculogenesis, permeability, histologic injury, compliance, and measures of right ventricular hypertrophy and right pulmonary pressure. Meta-analysis was performed to generate random effect size using standardized mean difference with 95% confidence interval.

RESULTS

A total of 29 studies met inclusion. Lung diseases included bronchopulmonary dysplasia, asthma, pulmonary hypertension, acute respiratory distress syndrome, chronic obstructive pulmonary disease, and pulmonary fibrosis. CdM improved all measures of lung structure and function. Moreover, no statistical difference was observed in any of the lung measures between MSCs and CdM.

CONCLUSIONS

In this meta-analysis of animal models recapitulating human lung disease, CdM improved lung structure and function and had an effect size comparable to MSCs.

Immunosuppressive Effects of Mesenchymal Stem Cells-derived Exosomes

Mesenchymal stem cells (MSCs) have become important seed cells in therapy because of their immunosuppressive function and anti-inflammatory effects. MSCs exert immunosuppressive effects through direct contact or paracrine action. The paracrine functions of MSCs are at least partially mediated by exosomes, which are membrane vesicles, carrying abundant proteins, nucleic acids and other active molecules. MSC-exos have heterogeneity. The exosomes from different donors, tissues generations of MSCs carry different bioactive molecules. These cargos are transferred to recipient cells by endocytosis or binding to proteins on the receptor surface to mediate intercellular communication between different cell types and affect the functions of the recipient cells. Exosomes play an important role in the regulation of the immune system. Exosomes derived from MSCs (MSC-exos) carry immunomodulatory effectors or transmit active signal molecules to regulate the biological activities of immune cells and thus mediating immune suppression, especially on macrophages and T cells. Mitochondria and autophagy-related pathways are also associated with MSC-exos immunosuppressive effects. Graphical Abstract.

Mesenchymal Stem/Stromal Cells Therapy for Sepsis and Acute Respiratory Distress Syndrome

Sepsis and acute respiratory distress syndrome (ARDS) constitute devastating conditions with high morbidity and mortality. Sepsis results from abnormal host immune response, with evidence for both pro- and anti-inflammatory activation present from the earliest phases. The "proinflammatory" response predominates initially causing host injury, with later-phase sepsis characterized by immune cell hypofunction and opportunistic superinfection. ARDS is characterized by inflammation and disruption of the alveolar-capillary membrane leading to injury and lung dysfunction. Sepsis is the most common cause of ARDS. Approximately 20% of deaths worldwide in 2017 were due to sepsis, while ARDS occurs in over 10% of all intensive care unit patients and results in a mortality of 30 to 45%. Given the fact that sepsis and ARDS share some-but not all-underlying pathophysiologic injury mechanisms, the lack of specific therapies, and their frequent coexistence in the critically ill, it makes sense to consider therapies for both conditions together. In this article, we will focus on the therapeutic potential of mesenchymal stem/stromal cells (MSCs). MSCs are available from several tissues, including bone marrow, umbilical cord, and adipose tissue. Allogeneic administration is feasible, an important advantage for acute conditions like sepsis or ARDS. They possess diverse mechanisms of action of relevance to sepsis and ARDS, including direct and indirect antibacterial actions, potent effects on the innate and adaptive response, and pro-reparative effects. MSCs can be preactivated thereby potentiating their effects, while the use of their extracellular vesicles can avoid whole cell administration. While early-phase clinical trials suggest safety, considerable challenges exist in moving forward to phase III efficacy studies, and to implementation as a therapy should they prove effective.

Preconditioning with rHMGB1 ameliorates lung ischemia-reperfusion injury by inhibiting alveolar macrophage pyroptosis via the Keap1/Nrf2/HO-1 signaling pathway

BACKGROUND

Lung ischemia-reperfusion injury (LIRI) is a complex pathophysiological process that can lead to poor patient outcomes. Inflammasome-dependent macrophage pyroptosis contributes to organ damage caused by ischemia/reperfusion injury. Oxidative stress and antioxidant enzymes also play an important role in LIRI. In this study, we conducted experiments to investigate whether and how preconditioning with rHMGB1 could ameliorate LIRI in a mouse model.

METHODS

Adult male BALB/c mice were anesthetized, the left hilus pulmonis was clamped, and reperfusion was performed. rHMGB1 was administered via intraperitoneal injection before anesthesia, and brusatol was given intraperitoneally every other day before surgery. We measured pathohistological lung tissue damage, wet/dry mass ratios of pulmonary tissue, and levels of inflammatory mediators to assess the extent of lung injury. Alveolar macrophage pyroptosis was evaluated by measuring release of lactate dehydrogenase, caspase-1 expression was assessed using flow cytometry, and gasdermin-D expression was analyzed using immunofluorescent staining. Levels of oxidative stress markers and antioxidant enzymes were also analyzed.

RESULTS

Preconditioning with rHMGB1 significantly ameliorated lung injury induced by ischemia-reperfusion, based on measurements of morphology, wet/dry mass ratios, as well as expression of IL-1β, IL-6, NF-κB, and HMGB1 in lung tissues. It also alleviated alveolar macrophage pyroptosis, reduced oxidative stress and restored the activity of antioxidant enzymes. These beneficial effects were mediated at least in part by the Keap1/Nrf2/HO-1 pathway, since they were reversed by the pathway inhibitor brusatol.

CONCLUSIONS

Preconditioning with rHMGB1 may protect against LIRI by suppressing alveolar macrophage pyroptosis. This appears to involve reduction of oxidative stress and promotion of antioxidant enzyme activity via the Keap1/Nrf2/HO-1 pathway.

Macrolets: Outsized Extracellular Vesicles Released from Lipopolysaccharide-Stimulated Macrophages that Trap and Kill Escherichia coli

Macrophages release a variety of extracellular vesicles (EVs). Here we describe a previously unreported class of EVs that are released from macrophages in response to Escherichia coli endotoxin, lipopolysaccharide (LPS), that we have named "macrolets" since they are extruded as large "droplets" released from macrophages. Morphologically, macrolets are anuclear, bounded by a single lipid membrane and structurally dependent on an actin cytoskeleton. Macrolets are enriched in tetraspanins and separable on this basis from their parent macrophages. Macrolets are distinguished from classic exosomes by their larger size (10–30 μm), discoid shape, and the presence of organelles. Macrolets are rich in both interleukin 6 (IL-6) and interleukin 6 receptor (IL-6R),and are capable of trapping and killing E. coli in association with production of reactive oxygen species. Our observations offer insights into the mechanisms by which macrophage activities may be amplified in sites of infection, inflammation, and healing.

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Macrolets, outsized extracellular vesicles, release from LPS-stimulated macrophages

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Macrolets are rich in tetraspanin proteins such as CD81, CD63, and CD9

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Macrolets capture and internalize E. coli bacteria within acidic compartments

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Macrolets kill E. coli by a mechanism associated with production of ROS and superoxide

Effects of Mesenchymal Stem Cell Coculture on Human Lung Small Airway Epithelial Cells

Mesenchymal stem cells (MSCs) and their secreted extracellular vesicles have been used effectively in different lung disease animal models and clinical trials. Their specific beneficial effects, the potential differences between MSCs derived from different organs, and interactions between MSC products and target cells still need to be studied further. Therefore, we investigated the effects of secreted products of human MSCs derived from the bone marrow and adipose tissue on human lung small airway epithelial (AE) cells in vitro. AE cells were cocultured with MSCs in inserts that allowed the free exchange of medium but did not allow direct cell-to-cell contact. We examined the effects on AE cell viability, proliferation, cell numbers, expression of AE cell-specific genes, and CD54 (intercellular adhesion molecule 1 (ICAM1)) surface positivity, as well as the secretion/uptake of growth factors relevant for AE cell. We found that coculture increased the viability of AE cells. The majority of AE cells expressed CD54 on their surface, but the percentage of cells being positive for CD54 did not increase in coculture. However, ICAM1 gene expression was increased in coculture. Also, we observed increased gene expression of mucin (MUC1), a lung-enriched cell surface glycoprotein. These observed effects were the same between bone marrow and adipose tissue MSCs. However, MSCs derived from adipose tissue reduced angiopoietin concentrations in coculture, whereas those from the bone marrow did not. Conclusively, MSCs influenced AE cells positively by increasing their viability and affecting gene expression, with some effects being specific for the tissue origin of MSCs.