RETRACTED: Exosomal miR-22-3p from human umbilical cord blood-derived mesenchymal stem cells protects against lipopolysaccharid-induced acute lung injury

Extracellular vesicles derived from mesenchymal stem cells ameliorate sulfur mustard-induced lung injury by regulating apoptosis via miR-146a-5p

Sulfur mustard (SM) is an extremely toxic chemical warfare agent. Although SM-induced toxicity has long been studied, due to its complexity, the characterization of the precise molecular pathway it targets has been remaining an ongoing area of research. Extracellular vesicles derived from human umbilical cord mesenchymal stem cells (hucMSC-EVs) are natural substances that participate in intercellular communication by delivering microRNA to target cells. Importantly, the microRNA content in EVs can be modified. MiR-146a-5p delivered by EVs were utilized and hucMSCs were further modified with miR-146a-5p mimics or inhibitors to collect EVs that over-(miR-146a-5p+-EVs) or underexpress (miR-146a-5p--EVs) miR-146a-5p. Transcriptome sequencing was used to identify potential mediators of the effects of miR-146a-5p delivered by hucMSC-EVs. Our results showed that hucMSC-EVs reduced SM-induced lung injury by mitigating apoptosis. These effects were enhanced by miR-146a-5p+-EVs and weakened by miR-146a-5p--EVs. Meanwhile, the relationship between apoptosis enhancing nuclease (AEN) and miR-146a-5p was discovered, a novel target of miR-146a-5p. Our study showed that hucMSC-EVs ameliorating sulfur mustard induced lung injury through miR-146a-5p, and AEN was one of the functional molecules in this process.

Human Umbilical Cord Mesenchymal Stem Cell Exosome-derived miR-335-5p Alleviated Lipopolysaccharide-induced Acute Lung Injury by Regulating the m6A Level of ITGβ4 Gene

BACKGROUND

Acute lung injury (ALI) is a serious complication that may accompany severe pneumonia in children. Derived from human umbilical cord mesenchymal stem cell exosome (HucMSC-Exo) can contribute to the regeneration of damaged lung tissue. This study aims to investigate the impact of HucMSC-Exo on ALI and its potential mechanisms.

METHODS

Firstly, RT-qPCR was performed to assess the expression of miR-335-5p. Subsequently, Pearson correlation analysis was performed to examine the correlation between METTL14 and miR-335-5p, as well as the correlation between METTL14 and ITGβ4, while RNA immunoprecipitation (RIP) was used to determine the m6A modification level of ITGβ4. Additionally, molecular biology techniques were employed to evaluate the expression of glycolysis-related factors. Definitively, an LPS-induced ALI model was established to investigate the effect of miR-335-5p on mice lung tissue.

RESULTS

miR-335-5p was found to be highly expressed in HucMSC-Exo. Transfection with miR-335-5p mimics resulted in increased glucose uptake. Pearson correlation analysis revealed a negative correlation between METTL14 and miR-335-5p, as well as between METTL14 and ITGβ4. The m6A level of ITGβ4 was elevated in ALI. Overexpression of METTL14 was found to reduce the expression of ITGβ4 and glucose levels, while overexpression of ITGβ4 reversed the effects of METTL14 overexpression. In vivo, results demonstrated that miR-335-5p could improve the extent of lung tissue lesions and reduce glycolytic levels.

CONCLUSION

This study revealed the mechanism by which miR-335-5p derived from HucMSC-Exo could alleviate LPS-induced ALI by regulating the m6A modification of ITGβ4, providing a new direction for the treatment of ALI.

Fabrication of blended nanofibrous cardiac patch transplanted with TGF-β3 and human umbilical cord MSCs-derived exosomes for potential cardiac regeneration after acute myocardial infarction

Acute myocardial infarction (AMI) is a common cardiovascular condition that progressively results in heart failure. In the present study, we have designed to load transforming growth factor beta 3 (TGF-β3) and cardio potential exosomes into the blended polycaprolactone/type I collagen (PCL/COL-1) nanofibrous patch (Exo@TGF-β3@NFs) and examined its feasibility for cardiac repair. The bioactivity of the developed NFs towards the migration and proliferation of human umbilical vein endothelial cells was determined using in vitro cell compatibility assays. Additionally, Exo@TGF-β3/NFs showed up-regulation of genes involved in angiogenesis and mesenchymal differentiations in vitro. The in vivo experiments performed 4 weeks after transplantation showed that the Exo@TGF-β3@NFs had a higher LV ejection fraction and fraction shortening functions. Subsequently, it has been determined that Exo@TGF-β3@NFs significantly reduced AMI size and fibrosis and increased scar thickness. The developed NFs approach will become a useful therapeutic approach for the treatment of AMI.

Circulating miRNA expression in extracellular vesicles is associated with specific injuries after multiple trauma and surgical invasiveness

Introduction

Two trauma treatment principles are Early Total Care (ETC), and Damage Control Orthopedics (DCO). Cellular mechanisms that underlie the connection between treatment type, its systemic effects, and tissue regeneration are not fully known. Therefore, this study aimed to: 1) profile microRNA (miRNA) expression in plasma derived Extracellular Vesicles (EVs) from a porcine multiple trauma model at different timepoints, comparing two surgical treatments; and 2) determine and validate the miRNA's messengerRNA (mRNA) targets.

Methods

The porcine multiple trauma model consisted of blunt chest trauma, liver laceration, bilateral femur fractures, and controlled haemorrhagic shock. Two treatment groups were defined, ETC (n=8), and DCO (n=8). Animals were monitored under Intensive Care Unit-standards, blood was sampled at 1.5, 2.5, 24, and 72 hours after trauma, and EVs were harvested from plasma. MiRNAs were analysed using quantitative Polymerase Chain Reaction arrays. MRNA targets were identified in silico and validated in vivo in lung and liver tissue.

Results

The arrays showed distinct treatment specific miRNA expression patterns throughout all timepoints, and miRNAs related to the multiple trauma and its individual injuries. EV-packed miRNA expression in the ETC group was more pro-inflammatory, indicating potentially decreased tissue regenerative capacities in the acute post-traumatic phase. In silico target prediction revealed several overlapping mRNA targets among the identified miRNAs, related to inflammation, (pulmonary) fibrosis, and Wnt-signalling. These were, among others, A Disintegrin and Metalloproteinase domain-containing protein 10, Collagen Type 1 Alpha 1 Chain, Catenin Beta Interacting Protein 1, and Signal Transducers and Activators of Transcription 3. Validation of these mRNA targets in the lung showed significant, treatment specific deregulations which matched the expression of their upstream miRNAs. No significant mRNA deregulations were observed in the liver.

Discussion

This study showed treatment specific, EV-packed miRNA expression patterns after trauma that correlated with mRNA expressions in the lungs, target organs over distance. A systemic response to the increased surgical trauma in the ETC group was identified, with various miRNAs associated with injuries from the trauma model, and involved in (systemic) inflammation, tissue regeneration. EV-transported miRNAs demonstrated a clear role in multiple trauma, warranting further research into tissue-tissue talk and therapeutic applications of EVs after trauma.

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.

Mesenchymal stem cells and their derived exosomes for ALI/ARDS: A promising therapy

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) is a serious clinical syndrome with a high morbidity and mortality. Presently, therapeutic approaches for ALI/ARDS primarily revolve around symptomatic supportive care encompassing mechanical ventilation and fluid management. Regrettably, the prognosis for most ALI/ARDS patients remains bleak due to the absence of effective treatment strategies. Even survivors of ALI/ARDS may have long-term pulmonary dysfunction and cognitive impairment. The quality of life has been seriously compromised. The emergence of mesenchymal stem cells (MSCs) and their exosomes has opened up an expansive realm of potential and optimism for addressing the plight of ALI/ARDS patients, as MSCs and their derived exosomes exhibit multifaceted capabilities, including anti-inflammatory properties, facilitation of tissue repair and regeneration, and apoptosis inhibition. Therefore, future research should focus on the possible mechanisms of MSCs and their derived exosomes for the treatment of ALI/ARDS and open up new avenues for their clinical applications.

Advances of mesenchymal stem cells and their derived extracellular vesicles as a promising therapy for acute respiratory distress syndrome: from bench to clinic

Acute respiratory distress syndrome (ARDS) is an acute inflammatory lung injury characterized by diffuse alveolar damage. The period prevalence of ARDS was 10.4% of ICU admissions in 50 countries. Although great progress has been made in supportive care, the hospital mortality rate of severe ARDS is still up to 46.1%. Moreover, up to now, there is no effective pharmacotherapy for ARDS and most clinical trials focusing on consistently effective drugs have met disappointing results. Mesenchymal stem cells (MSCs) and their derived extracellular vesicles (EVs) have spawned intense interest of a wide range of researchers and clinicians due to their robust anti-inflammatory, anti-apoptotic and tissue regeneration properties. A growing body of evidence from preclinical studies confirmed the promising therapeutic potential of MSCs and their EVs in the treatment of ARDS. Based on the inspiring experimental results, clinical trials have been designed to evaluate safety and efficacy of MSCs and their EVs in ARDS patients. Moreover, trials exploring their optimal time window and regimen of drug administration are ongoing. Therefore, this review aims to present an overview of the characteristics of mesenchymal stem cells and their derived EVs, therapeutic mechanisms for ARDS and research progress that has been made over the past 5 years.

Research progress of extracellular vesicles and exosomes derived from mesenchymal stem cells in the treatment of oxidative stress-related diseases

There is growing evidence that mesenchymal stem cell-derived extracellular vesicles and exosomes can significantly improve the curative effect of oxidative stress-related diseases. Mesenchymal stem cell extracellular vesicles and exosomes (MSC-EVs and MSC-Exos) are rich in bioactive molecules and have many biological regulatory functions. In this review, we describe how MSC-EVs and MSC-Exos reduce the related markers of oxidative stress and inflammation in various systemic diseases, and the molecular mechanism of MSC-EVs and MSC-Exos in treating apoptosis and vascular injury induced by oxidative stress. The results of a large number of experimental studies have shown that both local and systemic administration can effectively inhibit the oxidative stress response in diseases and promote the survival and regeneration of damaged parenchymal cells. The mRNA and miRNAs in MSC-EVs and MSC-Exos are the most important bioactive molecules in disease treatment, which can inhibit the apoptosis, necrosis and oxidative stress of lung, heart, kidney, liver, bone, skin and other cells, and promote their survive and regenerate.

EFFECT OF EXOSOMES DERIVED FROM BONE MARROW MESENCHYMAL STEM CELLS ON PROGRAMMED CELL DEATH IN BLAST-INDUCED LUNG INJURY IN RATS

ABSTRACT

Blast lung injuries (BLIs) are frequent because of industrial accidents and terrorist groups. Bone marrow mesenchymal stem cells (BMSCs) and exosomes derived from BMSCs (BMSCs-Exo) have become a hot topic in modern biology because of their significance in damage healing, immune regulation, and gene therapy. The aim of this study is to investigate the effect of BMSCs and BMSCs-Exo on BLI in rats caused by gas explosion. Here, BMSCs and BMSCs-Exo were transplanted into BLI rats via tail vein and then evaluated pathological alterations, oxidative stress, apoptosis, autophagy, and pyroptosis in the lung tissue. Through histopathology and changes in malondialdehyde (MDA) and superoxide dismutase (SOD) contents, we discovered that oxidative stress and inflammatory infiltration in the lungs were significantly reduced by BMSCs and BMSCs-Exo. After treatment with BMSCs and BMSCs-Exo, apoptosis-related proteins, such as cleaved caspase-3 and Bax, were significantly decreased, and the ratio of Bcl-2/Bax was significantly increased; the level of pyroptosis-associated proteins, including NLRP3, GSDMD-N, cleaved caspase-1, IL-1β, and IL-18, were decreased; autophagy-related proteins, beclin-1 and LC3, were downregulated while P62 was upregulated; the number of autophagosomes was decreased. In summary, BMSCs and BMSCs-Exo attenuate BLI caused by gas explosion, which may be associated with apoptosis, aberrant autophagy, and pyroptosis.

miRNA-Guided Regulation of Mesenchymal Stem Cells Derived from the Umbilical Cord: Paving the Way for Stem-Cell Based Regeneration and Therapy

The human body is an abundant source of multipotent cells primed with unique properties that can be exploited in a multitude of applications and interventions. Mesenchymal stem cells (MSCs) represent a heterogenous population of undifferentiated cells programmed to self-renew and, depending on their origin, differentiate into distinct lineages. Alongside their proven ability to transmigrate toward inflammation sites, the secretion of various factors that participate in tissue regeneration and their immunoregulatory function render MSCs attractive candidates for use in the cytotherapy of a wide spectrum of diseases and conditions, as well as in different aspects of regenerative medicine. In particular, MSCs that can be found in fetal, perinatal, or neonatal tissues possess additional capabilities, including predominant proliferation potential, increased responsiveness to environmental stimuli, and hypoimmunogenicity. Since microRNA (miRNA)-guided gene regulation governs multiple cellular functions, miRNAs are increasingly being studied in the context of driving the differentiation process of MSCs. In the present review, we explore the mechanisms of miRNA-directed differentiation of MSCs, with a special focus on umbilical cord-derived mesenchymal stem cells (UCMSCs), and we identify the most relevant miRNAs and miRNA sets and signatures. Overall, we discuss the potent exploitations of miRNA-driven multi-lineage differentiation and regulation of UCMSCs in regenerative and therapeutic protocols against a range of diseases and/or injuries that will achieve a meaningful clinical impact through maximizing treatment success rates, while lacking severe adverse events.

MicroRNA-22-3p in human umbilical cord mesenchymal stem cell-secreted exosomes inhibits granulosa cell apoptosis by targeting KLF6 and ATF4-ATF3-CHOP pathway in POF mice

BACKGROUND

Human umbilical cord mesenchymal stem cells (hUCMSCs)-derived exosomes carrying microRNAs (miRNAs) have promising therapeutic potential in various disorders, including premature ovarian failure (POF). Previous evidence has revealed the low plasma level of miR-22-3p in POF patients. Nevertheless, exosomal miR-22-3p specific functions underlying POF progression are unclarified.

METHODS

A cisplatin induced POF mouse model and in vitro murine ovarian granulosa cell (mOGC) model were established. Exosomes derived from miR-22-3p-overexpressed hUCMSCs (Exos-miR-22-3p) were isolated. CCK-8 assay and flow cytometry were utilized for measuring mOGC cell viability and apoptosis. RT-qPCR and western blotting were utilized for determining RNA and protein levels. The binding ability between exosomal miR-22-3p and Kruppel-like factor 6 (KLF6) was verified using luciferase reporter assay. Hematoxylin-eosin staining, ELISA, and TUNEL staining were performed for examining the alteration of ovarian function in POF mice.

RESULTS

Exos-miR-22-3p enhanced mOGC viability and attenuated mOGC apoptosis under cisplatin treatment. miR-22-3p targeted KLF6 in mOGCs. Overexpressing KLF6 reversed the above effects of Exos-miR-22-3p. Exos-miR-22-3p ameliorated cisplatin-triggered ovarian injury in POF mice. Exos-miR-22-3p repressed ATF4-ATF3-CHOP pathway in POF mice and cisplatin-treated mOGCs.

CONCLUSION

Exosomal miR-22-3p from hUCMSCs alleviates OGC apoptosis and improves ovarian function in POF mouse models by targeting KLF6 and ATF4-ATF3-CHOP pathway.

Therapeutic role of adipose-derived mesenchymal stem cells-derived extracellular vesicles in rats with obstructive sleep apnea hypopnea syndrome

Background

Obstructive sleep apnea hypopnea syndrome (OSAHS) is an underestimated sleep disorder that leads to multiple organ damages, including lung injury (LI). This paper sought to analyze the molecular mechanism of extracellular vesicles (EVs) from adipose-derived mesenchymal stem cells (ADSCs) in OSAHS-induced lung injury (LI) via the miR-22-3p/histone lysine demethylase 6 B (KDM6B)/high mobility group AT-hook 2 (HMGA2) axis.

Methods

ADSCs and ADSCs-EVs were separated and characterized. Chronic intermittent hypoxia (CIH) was used to mimic OSAHS-LI, followed by ADSCs-EVs treatment and hematoxylin and eosin staining, TUNEL, ELISA, and assays of inflammation and oxidative stress (MPO/ROS/MDA/SOD). The CIH cell model was established and treated with ADSCs-EVs. Cell injury was assessed by the assays of MTT, TUNEL, ELISA, and others. Levels of miR-22-3p, KDM6B, histone H3 trimethylation at lysine 27 (H3K27me3), and HMGA2 were determine by RT-qPCR or Western blot analysis. The transfer of miR-22-3p by ADSCs-EVs was observed by fluorescence microscopy. Gene interactions were analyzed by dual-luciferase assay or chromatin immunoprecipitation.

Results

ADSCs-EVs effectively alleviated OSAHS-LI by reducing lung tissue injury, apoptosis, oxidative stress, and inflammation. In vitro, ADSCs-EVs increased cell viability and reduced apoptosis, inflammation and oxidative stress. ADSCs-EVs delivered enveloped miR-22-3p into pneumonocytes to upregulate miR-22-3p expression, inhibit KDM6B expression, increase H3K27me3 levels on the HMGA2 promoter, and decrease HMGA2 mRNA levels. Overexpression of KDM6B or HMGA2 attenuated the protective role of ADSCs-EVs in OSAHS-LI.

Conclusion

ADSCs-EVs transferred miR-22-3p to pneumonocytes and reduced apoptosis, inflammation, and oxidative stress through KDM6B/HMGA2, mitigating OSAHS-LI progression.

Comprehensive analysis to identify the influences of SARS-CoV-2 infections to inflammatory bowel disease

BACKGROUND

Coronavirus disease 2019 (COVID-19) and inflammatory bowel disease (IBD) are both caused by a disordered immune response and have direct and profound impacts on health care services. In this study, we implemented transcriptomic and single-cell analysis to detect common molecular and cellular intersections between COVID-19 and IBD that help understand the linkage of COVID-19 to the IBD patients.

METHODS

Four RNA-sequencing datasets (GSE147507, GSE126124, GSE9686 and GSE36807) from Gene Expression Omnibus (GEO) database are extracted to detect mutual differentially expressed genes (DEGs) for IBD patients with the infection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) to find shared pathways, candidate drugs, hub genes and regulatory networks. Two single-cell RNA sequencing (scRNA-eq) datasets (GSE150728, PRJCA003980) are used to analyze the immune characteristics of hub genes and the proportion of immune cell types, so as to find common immune responses between COVID-19 and IBD.

RESULTS

A total of 121 common DEGs were identified among four RNA-seq datasets, and were all involved in the functional enrichment analysis related to inflammation and immune response. Transcription factors-DEGs interactions, miRNAs-DEGs coregulatory networks, and protein-drug interactions were identified based on these datasets. Protein-protein interactions (PPIs) was built and 59 hub genes were identified. Moreover, scRNA-seq of peripheral blood monocyte cells (PBMCs) from COVID-19 patients revealed a significant increase in the proportion of CD14+ monocytes, in which 38 of 59 hub genes were highly enriched. These genes, encoding inflammatory cytokines, were also highly expressed in inflammatory macrophages (IMacrophage) of intestinal tissues of IBD patients.

CONCLUSIONS

We conclude that COVID-19 may promote the progression of IBD through cytokine storms. The candidate drugs and DEGs-regulated networks may suggest effective therapeutic methods for both COVID-19 and IBD.

Exosomes derived from human umbilical cord mesenchymal stem cells protect against papain-induced emphysema by preventing apoptosis through activating VEGF-VEGFR2-mediated AKT and MEK/ERK pathways in rats

Introduction

Chronic obstructive pulmonary disease (COPD) is a leading cause of high mortality and heavy burden in the world. Unfortunately, emphysema, as an important component of COPD, has no curative treatments currently. Recently, human umbilical cord mesenchymal stem cells-derived exosomes (hUCMSC-Ex) constitute a promising alternative approach for tissue regeneration and repair. However, the roles of hUCMSC-Ex in emphysema and its mechanism are largely unknown. Here, we investigated the effect and the action mechanism of hUCMSC-Ex in repairing emphysema induced by papain in rats.

Methods

SD rats were used to establish a papain-induced emphysema model and estimate the effect and mechanism of hUCMSC-Ex treatment. H&E staining and mean linear intercept (MLI) were used to evaluate the hUCMSC-Ex effect on emphysema. Western blotting, TUNEL and miRNA-seq were used to investigate the molecular mechanisms of hUCMSC-Ex treatment in models of papain-induced emphysema.

Results

Papain treatment led to typical emphysema, while hUCMSC-Ex reversed emphysematous changes effectively. Apoptosis of endothelial cells and other types of cells were observed in models, while hUCMSC-Ex effectively prevented their apoptosis. hUCMSC-Ex repressed active caspase-3, activated VEGF-VEGFR2-mediated AKT pathway and MEK/ERK pathway in emphysematous lungs. Notably, several miRNAs, such as hsa-miR-10a-5p and hsa-miR-146a-5p, were target related to the roles of hUCMSC-Ex in papain-induced emphysema through VEGF-VEGFR2-mediated AKT and MEK/ERK pathways.

Conclusions

hUCMSC-Ex effectively rescued the papain-induced emphysema injury through VEGF-VEGFR2-mediated AKT pathway and MEK/ERK pathway.

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Exosomes from human umbilical cord mesenchymal stem cells (hUCMSC-Ex) pro protect against papain-injured emphysema in rats.

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hUCMSC-Ex prevent lung cells apoptosis by activating VEGF-VEGFR2-mediated AKT and MEK/ERK pathways.

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Several miRNAs, such as hsa-miR-10a-5p, were target related to the roles of hUCMSC-Ex.

Milk-Derived miR-22-3p Promotes Proliferation of Human Intestinal Epithelial Cells (HIECs) by Regulating Gene Expression

MicroRNA (miRNA) is small non-coding RNA involved in gene silencing and post-transcriptional regulation of gene expression. Milk exosomes are microvesicles containing microRNAs (miRNAs). miR-22-3p (miR-22) is plentiful in human milk exosomes and may contribute to intestinal development since milk exosomes and microRNAs are resistant to gastrointestinal digestion in infants. After miR-22 mimics were transfected to human intestinal crypt-like epithelial cells (HIECs) using Lipofectamine for 24 h, RNA was isolated for microarray assay. Microarray results show that miR-22 markedly regulates gene expression, and the roles of miR-22 include promotion of proliferation, regulation of immune functions, and inhibition of apoptosis. Based on the microarray results and miR-22 predicted target genes, CCAAT/enhancer-binding protein δ (C/EBPδ) may be an important direct target of miR-22. C/EBPδ is a transcription factor that regulates numerous biological processes including cell proliferation. In miR-22 transfected HIECs, expression of the C/EBPδ gene was significantly inhibited. Silencing of the C/EBPδ gene by siRNA resulted in increased proliferation of HIECs. A luciferase assay showed that miR-22 specifically binds to the 3'-untranslated region of C/EBPδ mRNA. In summary, milk-derived miR-22 promotes intestinal proliferation by modifying gene expression, and C/EBPδ may be an important target for miR-22 involved in this effect.

Extracellular vesicles in the pathogenesis and treatment of acute lung injury

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are common life-threatening lung diseases associated with acute and severe inflammation. Both have high mortality rates, and despite decades of research on clinical ALI/ARDS, there are no effective therapeutic strategies. Disruption of alveolar-capillary barrier integrity or activation of inflammatory responses leads to lung inflammation and injury. Recently, studies on the role of extracellular vesicles (EVs) in regulating normal and pathophysiologic cell activities, including inflammation and injury responses, have attracted attention. Injured and dysfunctional cells often secrete EVs into serum or bronchoalveolar lavage fluid with altered cargoes, which can be used to diagnose and predict the development of ALI/ARDS. EVs secreted by mesenchymal stem cells can also attenuate inflammatory reactions associated with cell dysfunction and injury to preserve or restore cell function, and thereby promote cell proliferation and tissue regeneration. This review focuses on the roles of EVs in the pathogenesis of pulmonary inflammation, particularly ALI/ARDS.

Advances in mesenchymal stromal cell therapy for acute lung injury/acute respiratory distress syndrome

Acute lung injury (ALI)/acute respiratory distress syndrome (ARDS) develops rapidly and has high mortality. ALI/ARDS is mainly manifested as acute or progressive hypoxic respiratory failure. At present, there is no effective clinical intervention for the treatment of ALI/ARDS. Mesenchymal stromal cells (MSCs) show promise for ALI/ARDS treatment due to their biological characteristics, easy cultivation, low immunogenicity, and abundant sources. The therapeutic mechanisms of MSCs in diseases are related to their homing capability, multidirectional differentiation, anti-inflammatory effect, paracrine signaling, macrophage polarization, the polarization of the MSCs themselves, and MSCs-derived exosomes. In this review, we discuss the pathogenesis of ALI/ARDS along with the biological characteristics and mechanisms of MSCs in the treatment of ALI/ARDS.

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.

The Extracellular MicroRNAs on Inflammation: A Literature Review of Rodent Studies

Inflammation is an indispensable biological process stimulated by infection and injuries. Inflammatory mechanisms related to extracellular vesicles (EVs), which are small membrane structures carrying various molecules, were summarized in this review. Emerging evidence from animal studies has highlighted the role of EVs in modulating inflammatory responses, by transporting various molecules involved in host defense. In this review, we have discussed the role of EV miRNAs in inflammation. Rodent studies associated with extracellular miRNAs in inflammatory diseases, published from 2012 to 2022, were explored from PUBMED, EMBASE, and MEDLINE. A total of 95 studies were reviewed. In summary, EV-associated miRNAs play a key role in various diseases, including organ injury, immune dysfunction, neurological disease, metabolic syndrome, vesicular disease, arthritis, cancer, and other inflammatory diseases. Diverse EV-associated miRNAs regulate inflammasome activation and pro- and anti-inflammatory cytokine levels by targeting genes.

Mesenchymal Stem Cells Attenuate Acute Lung Injury in Mice Partly by Suppressing Alveolar Macrophage Activation in a PGE2-Dependent Manner

Mesenchymal stem cells (MSCs) have been demonstrated to attenuate acute lung injury (ALI). We also found that they can suppress the activation of alveolar macrophages (AMs), which can partly account for their therapeutic effects. MSCs do not inherently own immunosuppressive effects, when co-cultured with inflammatory immune cells, MSCs can be activated by inflammatory cytokines and meanwhile exert immunosuppressive effects. In order to further research, RNA sequencing (RNA-seq) of MSCs cultured before and after co-culturing with activated macrophages was performed. The data suggested a total of 5268 differentially expressed genes (DEGs) along the process. We used the data of 2754 upregulated DEGs to develop a signaling network of genes and the transcription factors targeting them in order to predict the altered functions of MSCs after exposure to inflammatory stimuli. This constructed network revealed some critical target genes and potential roles of MSCs under inflammatory conditions. According to the network, Ptgs2 was assumed to be an important gene participating in the immunosuppressive effects of MSCs. We also identified significant increases in the expression of COX2 protein and the secretion of PGE2 from MSCs. The use of the COX2 inhibitor NS-398 restrained the secretion of PGE2 and reversed the suppression of macrophage activation by MSCs in vitro. In addition, a selective antagonist of PGE2 binding receptor (EP4 receptor), GW627368X, also reversed the inhibitory effects of MSCs on AMs and the protective effects in ALI mouse. In summary, the therapeutic effects of MSCs on ALI partly occur through suppressing AM activation via PGE2 binding to EP4 receptor.

Molecular Insight into the Therapeutic Effects of Stem Cell-Derived Exosomes in Respiratory Diseases and the Potential for Pulmonary Delivery

Respiratory diseases are the cause of millions of deaths annually around the world. Despite the recent growth of our understanding of underlying mechanisms contributing to the pathogenesis of lung diseases, most therapeutic approaches are still limited to symptomatic treatments and therapies that only delay disease progression. Several clinical and preclinical studies have suggested stem cell (SC) therapy as a promising approach for treating various lung diseases. However, challenges such as the potential tumorigenicity, the low survival rate of the SCs in the recipient body, and difficulties in cell culturing and storage have limited the applicability of SC therapy. SC-derived extracellular vesicles (SC-EVs), particularly SC-derived exosomes (SC-Exos), exhibit most therapeutic properties of stem cells without their potential drawbacks. Similar to SCs, SC-Exos exhibit immunomodulatory, anti-inflammatory, and antifibrotic properties with the potential to be employed in the treatment of various inflammatory and chronic respiratory diseases. Furthermore, recent studies have demonstrated that the microRNA (miRNA) content of SC-Exos may play a crucial role in the therapeutic potential of these exosomes. Several studies have investigated the administration of SC-Exos via the pulmonary route, and techniques for SCs and SC-Exos delivery to the lungs by intratracheal instillation or inhalation have been developed. Here, we review the literature discussing the therapeutic effects of SC-Exos against respiratory diseases and advances in the pulmonary route of delivery of these exosomes to the damaged tissues.

Small Extracellular Vesicles Containing miR-34c Derived from Bone Marrow Mesenchymal Stem Cells Regulates Epithelial Sodium Channel via Targeting MARCKS

Epithelial sodium channel (ENaC) is a pivotal regulator of alveolar fluid clearance in the airway epithelium and plays a key role in the treatment of acute lung injury (ALI), which is mainly composed of the three homologous subunits (α, β and γ). The mechanisms of microRNAs in small extracellular vesicles (sEVs) derived from mesenchymal stem cell (MSC-sEVs) on the regulation of lung ion transport are seldom reported. In this study, we aimed at investigating whether miR-34c had an effect on ENaC dysfunction induced by lipopolysaccharide and explored the underlying mechanism in this process. Primarily, the effect of miR-34c on lung edema and histopathology changes in an ALI mouse model was investigated. Then the uptake of PKH26-labeled sEVs was observed in recipient cells, and we observed that the overexpression of miR-34c in MSC-sEVs could upregulate the LPS-inhibited γ-ENaC expression. The dual luciferase reporter gene assay demonstrated that myristoylated alanine-rich C kinase substrate (MARCKS) was one of target genes of miR-34c, the protein expression of which was negatively correlated with miR-34c. Subsequently, either upregulating miR-34c or knocking down MARCKS could increase the protein expression of phospho-phosphatidylinositol 3-kinase (p-PI3K) and phospho-protein kinase B (p-AKT), implying a downstream regulation pathway was involved. All of the above suggest that miR-34c in MSC-sEVs can attenuate edematous lung injury via enhancing γ-ENaC expression, at least partially, through targeting MARCKS and activating the PI3K/AKT signaling pathway subsequently.

Mechanisms governing the therapeutic effect of mesenchymal stromal cell-derived extracellular vesicles: A scoping review of preclinical evidence

Compelling evidence supports the therapeutic benefit of extracellular vesicles (EVs). EVs are nanostructures with a lipid bilayer membrane that are secreted by multiple cells, including mesenchymal stromal cells (MSCs), as means of cellular communication. MSC-EVs, resembling their MSC origin, carry protected immunomodulatory and pro-regenerative cargoes to targeted neighboring or distant cells and tissues. Though treatments focused on MSC-EVs have emerged as greatly versatile approaches to modulate multiple inflammatory-related conditions, crucial concerns, including the possibility of increasing therapeutic outcomes by pre-conditioning parental MSCs or engineering derived EVs and clarification of the most relevant mechanisms of action, remain. Here, we summarize the large amount of preclinical research surrounding the modulation of beneficial effects by MSC-EVs.

Differential Lung Protective Capacity of Exosomes Derived from Human Adipose Tissue, Bone Marrow, and Umbilical Cord Mesenchymal Stem Cells in Sepsis-Induced Acute Lung Injury

Exosomes derived from human mesenchymal stem cells (hMSCs) have the capacity to regulate various biological events associated with sepsis-induced acute respiratory distress syndrome (ARDS), including cellular immunometabolism, the production of proinflammatory cytokines, allowing them to exert therapeutic effects. However, little is known about which type of hMSC-derived exosomes (hMSC-exo) is more effective and suitable for the treatment of sepsis-induced ARDS. The purpose of this study is to compare the efficacy of hMSC-derived exosomes from human adipose tissue (hADMSC-exo), human bone marrow (hBMMSC-exo), and human umbilical cord (hUCMSC-exo) in the treatment of sepsis-induced ARDS. We cocultured lipopolysaccharide- (LPS-) stimulated RAW264.7 macrophage cells with the three kinds of hMSCs and found that all hMSCs reduced the glycolysis level and the content of lactic acid in macrophages. Accordingly, the expression of proinflammatory cytokines also decreased. Notably, the protective effects of hMSCs from adipose tissue were more obvious than those of bone marrow and umbilical cord hMSCs. However, this protective effect was eliminated when an exosome inhibitor, GW4869, was added. Subsequently, we extracted and cocultured hMSC-derived exosomes with LPS-stimulated RAW264.7 cells and found that all three kinds of exosomes exerted a similar protective effect as their parental cells, with exosomes from adipose hMSCs showing the strongest protective effect. Finally, an experimental sepsis model in mice was established, and we found that all three types of hMSCs have obvious lung-protective effects, in reducing lung injury scores, lactic acid, and proinflammatory cytokine levels in the lung tissues and decreasing the total protein content and inflammatory cell count in the bronchoalveolar lavage fluid (BALF), and also can attenuate the systemic inflammatory response and improve the survival rate of mice. Intravenous injection of three types of hMSC-exo, in particular those derived from adipose hADMSCs, also showed lung-protective effects in mice. These findings revealed that exosomes derived from different sources of hMSCs can effectively downregulate sepsis-induced glycolysis and inflammation in macrophages, ameliorate the lung pathological damage, and improve the survival rate of mice with sepsis. It is worth noting that the protective effect of hADMSC-exo is better than that of hBMMSC-exo and hUCMSC-exo.

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.

Extracellular Vesicles: A New Paradigm for Cellular Communication in Perioperative Medicine, Critical Care, and Pain Management

Extracellular vesicles (EVs) play critical roles in many health and disease states, including ischemia, inflammation, and pain, which are major concerns in the perioperative period and in critically ill patients. EVs are functionally active, nanometer-sized, membrane-bound vesicles actively secreted by all cells. Cell signaling is essential to physiological and pathological processes, and EVs have recently emerged as key players in intercellular communication. Recent studies in EV biology have improved our mechanistic knowledge of the pathophysiological processes in perioperative and critical care patients. Studies also show promise in using EVs in novel diagnostic and therapeutic clinical applications. This review considers the current advances and gaps in knowledge of EVs in the areas of ischemia, inflammation, pain, and in organ systems that are most relevant to anesthesiology, perioperative medicine, critical care, and pain management. We expect the reader will better understand the relationship between EVs and perioperative and critical care pathophysiological states and their potential use as novel diagnostic and therapeutic modalities.

Recent Insight on the Non-coding RNAs in Mesenchymal Stem Cell-Derived Exosomes: Regulatory and Therapeutic Role in Regenerative Medicine and Tissue Engineering

Advances in the field of regenerative medicine and tissue engineering over the past few decades have paved the path for cell-free therapy. Numerous stem cell types, including mesenchymal stem cells (MSCs), have been reported to impart therapeutic effects via paracrine secretion of exosomes. The underlying factors and the associated mechanisms contributing to these MSC-derived exosomes' protective effects are, however, poorly understood, limiting their application in the clinic. The exosomes exhibit a diversified repertoire of functional non-coding RNAs (ncRNAs) and have the potential to transfer these biologically active transcripts to the recipient cells, where they are found to modulate a diverse array of functions. Altered expression of the ncRNAs in the exosomes has been linked with the regenerative potential and development of various diseases, including cardiac, neurological, skeletal, and cancer. Also, modulating the expression of ncRNAs in these exosomes has been found to improve their therapeutic impact. Moreover, many of these ncRNAs are expressed explicitly in the MSC-derived exosomes, making them ideal candidates for regenerative medicine, including tissue engineering research. In this review, we detail the recent advances in regenerative medicine and summarize the evidence supporting the altered expression of the ncRNA repertoire specific to MSCs under different degenerative diseases. We also discuss the therapeutic role of these ncRNA for the prevention of these various degenerative diseases and their future in translational medicine.

Exosome-inflammasome crosstalk and their roles in inflammatory responses

Inflammasome is a complex of multiple proteins found in cytoplasm of the cells activated by infectious and/or non-infectious stimuli. This complex involves caspase-1 activation, leading to unconventional secretion of interleukin-1β (IL-1β) and IL-18 and inflammatory cascade. Exosome is the nanoscale membrane-bound extracellular vesicle that plays significant roles in intercellular communications by carrying bioactive molecules, e.g., proteins, RNAs, microRNAs (miRNAs), DNAs, from one cell to the others. In this review, we provide the update information on the crosstalk between exosome and inflammasome and their roles in inflammatory responses. The effects of inflammasome activation on exosomal secretion are summarized. On the other hand, the (dual) effects of exosomes on inhibiting and promoting inflammasome activation are discussed. Finally, perspectives on therapeutic roles of exosomes in human diseases and future direction of the research on exosome-inflammasome crosstalk are provided.