MicroRNA Cargo of Extracellular Vesicles from Alcohol-exposed Monocytes Signals Naive Monocytes to Differentiate into M2 Macrophages

The role of gut microbiota, exosomes, and their interaction in the pathogenesis of ALD

BACKGROUND

The liver disorders caused by alcohol abuse are termed alcoholic-related liver disease (ALD), including alcoholic steatosis, alcoholic steatohepatitis, alcoholic hepatitis, and alcoholic cirrhosis, posing a significant threat to human health. Currently, ALD pathogenesis has not been completely clarified, which is likely to be related to the direct damage caused by alcohol and its metabolic products, oxidative stress, gut dysbiosis, and exosomes.

AIMS

The existing studies suggest that both the gut microbiota and exosomes contribute to the development of ALD. Moreover, there exists an interaction between the gut microbiota and exosomes. We discuss whether this interaction plays a role in the pathogenesis of ALD and whether it can be a potential therapeutic target for ALD treatment.

KEY SCIENTIFIC CONCEPTS OF REVIEW

Chronic alcohol intake alters the diversity and composition of gut microbiota, which greatly contributes to ALD's progression. Some approaches targeting the gut microbiota, including probiotics, fecal microbiota transplantation, and phage therapy, have been confirmed to effectively ameliorate ALD in many animal experiments and/or several clinical trials. In ALD, the levels of exosomes and the expression profile of microRNA have also changed, which affects the pathogenesis of ALD. Moreover, there is an interplay between exosomes and the gut microbiota, which also putatively acts as a pathogenic factor of ALD.

Molecular regulators of alcoholic liver disease: a comprehensive analysis of microRNAs and long non-coding RNAs

Many biomolecules and signaling pathways are involved in the development of alcoholic liver disease (ALD). The molecular mechanisms of ALD are not fully understood and there is no effective treatment. Numerous studies have demonstrated the critical role of non-coding RNAs, including long non-coding RNAs (lncRNAs) and microRNAs (miRNAs), in ALD. miRNAs play an important regulatory role in the pathogenesis of ALD by controlling critical biological processes such as inflammation, oxidative stress, lipid metabolism, apoptosis and fibrosis. Among them, miR-155, miR-223 and miR-34a play a central role in these processes and influence the pathological process of ALD. In addition, lncRNAs are involved in regulating liver injury and repair by interacting with miRNAs to form a complex regulatory network. These findings help to elucidate the molecular mechanisms of ALD and provide a scientific basis for the development of new diagnostic markers and therapeutic targets. In this article, we review the roles and mechanisms of LncRNAs and miRNAs in ALD and their potential use as diagnostic markers and therapeutic targets.

Bioengineered extracellular vesicles: The path to precision medicine in liver diseases

Extracellular vesicles (EVs) are membrane-bound entities secreted by each cell, categorized as, exosomes, microvesicles or apoptotic bodies based on their size and biogenesis. They serve as promising vectors for drug delivery due to their capacity to carry diverse molecular signatures reflective of their cell of origin. EV research has significantly advanced since their serendipitous discovery, with recent studies focusing on their roles in various diseases and their potential for targeted therapy. In liver diseases, EVs are particularly promising for precision medicine, providing diagnostic and therapeutic potential in conditions such as metabolic dysfunction-associated steatotic liver disease and metabolic dysfunction-associated steatohepatitis, hepatocellular carcinoma, alcoholic liver disease, liver fibrosis, and acute liver failure. Despite challenges in isolation and characterization, engineered EVs have shown efficacy in delivering therapeutic agents with improved targeting and reduced side effects. As research progresses, EVs hold great promise to revolutionize precision medicine in liver diseases, offering targeted, efficient, and versatile therapeutic options. In this review, we summarize various techniques for loading EVs with therapeutic cargo including both passive and active methods, and the potential of bioengineered EVs loaded with various molecules, such as miRNAs, proteins, and anti-inflammatory drugs in ameliorating clinical pathologies of liver diseases.

Origin, Function, and Implications of Intestinal and Hepatic Macrophages in the Pathogenesis of Alcohol-Associated Liver Disease

Macrophages are members of the human innate immune system, and the majority reside in the liver. In recent years, they have been recognized as essential players in the maintenance of liver and intestinal homeostasis as well as key guardians of their respective immune systems, and they are increasingly being recognized as such. Paradoxically, they are also likely involved in chronic pathologies of the gastrointestinal tract and potentially in the alteration of the gut-liver axis in alcohol use disorder (AUD) and alcohol-associated liver disease (ALD). To date, the causal relationship between macrophages, the pathogenesis of ALD, and the immune dysregulation of the gut remains unclear. In this review, we will discuss our current understanding of the heterogeneity of intestinal and hepatic macrophages, their ontogeny, the potential factors that regulate their origin, and the evidence of how they are associated with the manifestation of chronic inflammation. We will also illustrate how the micro-environment of the intestine shapes the phenotypes and functionality of the macrophage compartment in both the intestines and liver and how they change during chronic alcohol abuse. Finally, we highlight the obstacles to current research and the prospects for this field.

The functional regulation between extracellular vesicles and the DNA damage responses

The DNA damage response (DDR) is a crucial regulatory mechanism for the survival of organisms, and irregularity of DDR may contribute to the development of various diseases, including tumors, making it is a prominent topic in therapeutic research. Extracellular vesicles (EVs), as important mediators of intercellular communication, have been extensively studied in recent years. Notably, an increasing number of studies have revealed a strong connection between DDR and EVs. On one hand, DNA damage affects the release of EVs and their compositional content; on the other hand, EVs can dictate cell survival or death by modulating DDR in both the parental and the recipient cells. This review outlines current progress in the inter-regulatory relationship between EVs and DDR, with special emphasis on the effects of EVs derived from various sources on DDR in recipient cells. In addition, the potential applications of EVs in research and tumor therapy are discussed.

Immunology and treatments of fatty liver disease

Alcoholic liver disease (ALD) and non-alcoholic fatty liver disease (NAFLD) are two major chronic liver diseases worldwide. The triggers for fatty liver can be derived from external sources such as adipose tissue, the gut, personal diet, and genetics, or internal sources, including immune cell responses, lipotoxicity, hepatocyte death, mitochondrial dysfunction, and extracellular vesicles. However, their pathogenesis varies to some extent. This review summarizes various immune mechanisms and therapeutic targets associated with these two types of fatty liver disease. It describes the gut-liver axis and adipose tissue-liver crosstalk, as well as the roles of different immune cells (both innate and adaptive immune cells) in fatty liver disease. Additionally, mitochondrial dysfunction, extracellular vesicles, microRNAs (miRNAs), and gastrointestinal hormones are also related to the pathogenesis of fatty liver. Understanding the pathogenesis of fatty liver and corresponding therapeutic strategies provides a new perspective for developing novel treatments for fatty liver disease.

Visium spatial transcriptomics and proteomics identifies novel hepatic cell populations and transcriptomic signatures of alcohol-associated hepatitis

BACKGROUND

Alcohol-associated hepatitis (AH) is the clinical manifestation of alcohol-associated liver disease (ALD). AH is a complex disease encompassing the dysregulation of many cells and cell subpopulations. This study used a hepatic spatial transcriptomic and proteomic approach (10X Genomics Visium) to identify hepatic cell populations and their associated transcriptomic and proteomic alterations in human AH.

METHODS

Formalin-fixed paraffin-embedded liver tissue from AH patients (n = 2) and non-ALD controls (donors) (n = 2) were used for Visium spatial transcriptomic and proteomic analysis.

RESULTS

AH cell clusters and cell markers were drastically different in regard to tissue pattern and number of cell types compared to non-ALD controls. Cholangiocytes, endothelial cells, macrophages, and stellate cells were more profuse in AH relative to non-ALD controls. Transcriptionally, proliferating cell nuclear antigen-positive (PCNA+) hepatocytes in AH more closely resembled cholangiocytes suggesting they were non-functional hepatocytes derived from cholangiocytes. Furthermore, mitochondria protein-coding genes were reduced in AH versus non-ALD control hepatocytes, suggesting reduced functionality and loss of regenerative mechanisms. Macrophages in AH exhibited elevated gene expression involved in exosomes as compared to non-ALD controls. The most upregulated macrophage genes observed in AH were those involved in exosome trafficking. Gene and protein signatures of disease-associated hepatocytes (ANXA2+/CXCL1+/CEACAM8+) were elevated in AH and could visually identify a pre-malignant lesion.

CONCLUSIONS

This study identified global cell type alterations in AH and distinct transcriptomic changes between AH and non-ALD controls. These findings characterize cellular plasticity and profuse transcriptomic and proteomic changes that are apparent in AH and contribute to the identification of novel therapeutics.

Extracellular vesicles from chronic lymphocytic leukemia cells promote leukemia aggressiveness by inducing the differentiation of monocytes into nurse-like cells via an RNA-dependent mechanism

Chronic lymphocytic leukemia (CLL) cells receive several stimuli from surrounding cells, such as B-cell receptor (BCR) stimulation, and can manipulate their microenvironment via extracellular vesicle (EV) release. Here, we investigated the small RNA content (microRNA and YRNA) of CLL-EVs from leukemic cells cultured with/without BCR stimulation. We highlight an increase of miR-155-5p, miR-146a-5p, and miR-132-3p in EVs and in cells after BCR stimulation (p < 0.05, n = 25). CLL-EVs were preferentially internalized by monocytes (p = 0.0019, n = 6) and able to deliver microRNAs and the hY4 RNA. Furthermore, BCR CLL-EV induced modifications in monocytes (shape change, microRNA and gene expression, secretome) suggesting nurse-like cell (NLC) differentiation, the tumor-associated macrophages of CLL. Functionally, monocytes treated with BCR CLL-EVs protect CLL cells from spontaneous apoptosis by pro-survival cytokine production and induce their migration as well as the migration of other immune cells. We finally reported by transfection experiments that hY4 is able to induce the expression of CCL24, a key gene in M2 macrophage differentiation. In conclusion, we showed that BCR stimulation modifies the small RNA content of CLL-EVs and that the addition of leukemic EVs to monocytes leads to monocyte differentiation into NLCs establishing a protective microenvironment that supports leukemic cell survival.

Extracellular Vesicles and Micro-RNAs in Liver Disease

Progression of liver disease is dependent on intercellular signaling, including those mediated by extracellular vesicles (EVs). Within these EVs, microRNAs (miRNAs) are packaged to selectively silence gene expression in recipient cells for upregulating or downregulating a specific pathway. Injured hepatocytes secrete EV-associated miRNAs which can be taken up by liver sinusoidal endothelial cells, immune cells, hepatic stellate cells, and other cell types. In addition, these recipient cells will secrete their own EV-associated miRNAs to propagate a response throughout the tissue and the circulation. In this review, we comment on the implications of EV-miRNAs in the progression of alcohol-associated liver disease, metabolic dysfunction-associated steatohepatitis, viral and parasitic infections, liver fibrosis, and liver malignancies. We summarize how circulating miRNAs can be used as biomarkers and the potential of utilizing EVs and miRNAs as therapeutic methods to treat liver disease.

Cannabinoids shift the basal ganglia microRNA m 6 A methylation profile towards an anti-inflammatory phenotype in SIV-infected rhesus macaques

Background

Epitranscriptomic modifications modulate diverse biological processes like regulation of gene expression, abundance, location and function. N6-methyladenosine (m 6 A) methylation has been shown to regulate various diseases, including cancer and inflammation. While there is evidence that m 6 A modification is functionally relevant in neural development and differentiation, the role of m 6 A modification in HIV neuropathogenesis is unknown.

Methods

Here, we used anti-N6-methyladenosine (m 6 A) antibody immunoprecipitation and microarray profiling to identify m 6 A modifications in miRNAs in basal ganglia (BG) of Rhesus macaques (RMs) that were uninfected (VEH) and SIV-infected on combination anti-retroviral therapy (cART) and either VEH-treated (VEH/SIV/cART), or THC:CBD-treated (THC:CBD/SIV/cART). Ingenuity pathway analysis was conducted to understand the biological implications of miRNA m 6 A methylation in HIV neuropathogenesis. Finally, to understand the functional significance of m 6 A modifications in miRNAs, we overexpressed FAM-labeled wild-type or m 6 A-modified miR-194-5p in SCC-25 cells and determined its impact on the expression of its target, STAT1, an interferon-stimulated transcription factor known to drive persistent neuroinflammation in several neurodegenerative diseases.

Results

HIV/SIV infection promoted an overall hypomethylated miRNA m 6 A profile. While the overall hypomethylated m 6 A profile was not significantly impacted by THC:CBD, specific miRNAs predicted to target proinflammatory genes showed markedly reduced m 6 A methylation levels compared to the VEH-treated RMs. Additionally, specific BG tissue miRNAs bearing m 6 A epi-transcriptomic marks were transferred and detected in BG-derived extracellular vesicles. Mechanistically, the DRACH motif in the seed region of miR-194-5p was significantly m 6 A hypomethylated in THC:CBD/SIV/cART RMs. In SCC-25 cells, unlike wild-type miR-194-5p, transfected m 6 A-modified miR-194-5p mimics failed to downregulate STAT1 protein expression. Further, compared to VEH/SIV/cART RMs, THC:CBD administration significantly reduced m 6 A methylation of 44 miRNAs directly involved in regulating CNS network genes.

Conclusions

These results underscore the need for investigating the qualitative, and posttranscriptional modifications in RNA along with the more traditional, quantitative alterations in pathological conditions or in response to disease modifying treatments. Our findings indicate that m 6 A epitranscriptomic marks in the seed nucleotide region can impair miRNA function and that cannabinoids may preserve it by reducing m 6 A methylation levels. Finally, these findings provide a novel mechanistic (miRNA m 6 A hypomethylation) explanation underlying the anti-neuroinflammatory effects of phytocannabinoids in HIV/SIV infection.

Emerging role of exosomes during the pathogenesis of viral hepatitis, non-alcoholic steatohepatitis and alcoholic hepatitis

Extracellular vesicles (EVs) refer to a diverse range of membranous vesicles that are secreted by various cell types, they can be categorized into two primary subgroups: exosomes and microvesicles. Specifically, exosomes constitute a nanosized subset of EVs characterized by their intact lipid bilayer and diameters ranging from 30 to 150 nm. These vesicles play a crucial role in intercellular communication by transporting a diverse array of biomolecules, which act as cargoes for this communication process. Exosomes have demonstrated significant implications in a wide range of biologic processes and pathologic conditions, including immunity, development, cancer, neurodegenerative diseases, and liver diseases. Liver diseases significantly contribute to the global burden of morbidity and mortality, yet their pathogenesis remains complex and effective therapies are relatively scarce. Emerging evidence suggests that exosomes play a modulatory role in the pathogenesis of liver diseases, including viral hepatitis, non-alcoholic steatohepatitis (NASH), and alcoholic hepatitis (AH). These findings bolster our confidence in the potential of exosomes as biomarkers and therapeutic tools for the diagnosis and treatment of liver diseases. In this comprehensive review, we offer a straightforward overview of exosomes and summarize the current understanding of their role in the pathogenesis of liver diseases. This provides a foundation for novel diagnostic and therapeutic approaches in the treatment of liver diseases.

Extracellular vesicle miR-206 improves chronic binge alcohol-mediated decreased myoblast differentiation in SIV-infected female macaques

Alcohol misuse in people with human immunodeficiency virus (HIV) (PWH) and chronic binge alcohol (CBA) administration in simian immunodeficiency virus (SIV)-infected macaques are associated with increased physical frailty and impaired functional skeletal muscle mass, respectively. Previous studies by our group demonstrate that muscle-enriched microRNAs (myomiRs) are differentially expressed in skeletal muscle (SKM) from CBA-administered SIV-infected male macaques and their altered expression contributes to impaired differentiation of SKM stem cells or myoblasts. MicroRNAs can be transported in extracellular vesicles (EVs) to mediate numerous cellular responses through intercellular communication. The present study tested the hypothesis that EV-mediated delivery of miR-206 can ameliorate CBA-mediated decreases in myoblast differentiation. Myoblasts were isolated from SKM of female SIV-infected, antiretroviral therapy-treated macaques that received either CBA (2.5 g/kg/day, CBA/SIV) or water (VEH/SIV) for 14.5 mo. Myotube and myotube-derived EV myomiR expression, including miR-206, was lower in the CBA/SIV group. Overexpression of miR-206 decreased histone deacetylase 4 (HDAC4) and paired box 7 (PAX7) expression in myotubes and increased fusion index, a differentiation index, in CBA/SIV-derived myotubes. Similarly, EV-mediated delivery of miR-206 increased both fusion index and myotube density of CBA/SIV-derived myoblasts. These results support the potential therapeutic utility of EVs in delivering myomiRs to improve SKM stem cell differentiation.NEW & NOTEWORTHY Alcohol decreases skeletal muscle myoblast differentiation into myotubes, which is associated with decreased expression of microRNA-206. We show that delivering exogenous miR-206 in plasma-derived extracellular vesicles (EVs) to myoblasts derived from alcohol-administered animals increases myotube differentiation. These results support the potential therapeutic utility of EVs in delivering muscle-enriched microRNAs to improve skeletal muscle stem cell differentiation.

Probiotics alleviate chronic ethanol exposure-induced anxiety-like behavior and hippocampal neuroinflammation in male mice through gut microbiota-derived extracellular vesicles

BACKGROUND

Probiotics can colonize both the human and animal bodies and consist of active microorganisms that are beneficial to health. The use of probiotics has been shown to alleviate certain neurological diseases and disturbances in gut microbiota resulting from chronic ethanol exposure. Research indicates that probiotics can influence the nervous system via the microbial-gut-brain axis, wherein extracellular vesicles secreted by the gut microbiota play a significant role in this process.

RESULTS

In this study, we first established a 30-day ethanol exposure and probiotic gavage mouse model, both of which influenced behavior and the composition of gut microbiota. We then extracted gut microbiota-derived extracellular vesicles from the feces of these model mice and injected them into new mice via the tail vein to assess the role of each set of extracellular vesicles. The results indicated that the extracellular vesicles derived from the intestinal microbiota in the ethanol group induced anxiety-like behavior and hippocampal neuroinflammation in the recipient mice. In contrast, the extracellular vesicles secreted by the gut microbiota from the probiotic group mitigated the anxiety-like behavior and neuroinflammation induced by ethanol-influenced extracellular vesicles.

CONCLUSIONS

Our study demonstrates that extracellular vesicles secreted by the gut microbiota can influence the nervous system via the microbial-gut-brain axis. Furthermore, we found that the extracellular vesicles secreted by the gut microbiota from the probiotic group exert a beneficial therapeutic effect on anxiety and hippocampal neuroinflammation.

Novel insights into the role of immunomodulatory extracellular vesicles in the pathogenesis of liver fibrosis

Liver fibrosis, a chronic and long-term disease, can develop into hepatocellular carcinoma (HCC) and ultimately lead to liver failure. Early diagnosis and effective treatment still face significant challenges. Liver inflammation leads to liver fibrosis through continuous activation of hepatic stellate cells (HSCs) and the accumulation of immune cells. Intracellular communication among various immune cells is important for mediating the inflammatory response during fibrogenesis. Extracellular vesicles (EVs), which are lipid bilayer membrane-enclosed particles naturally secreted by cells, make great contributions to cell-cell communication and the transport of bioactive molecules. Nearly all the cells that participate in liver fibrosis release EVs loaded with lipids, proteins, and nucleic acids. EVs from hepatocytes, immune cells and stem cells are involved in mediating the inflammatory microenvironment of liver fibrosis. Recently, an increasing number of extracellular vesicle-based clinical applications have emerged, providing promising cell-free diagnostic and therapeutic tools for liver fibrosis because of their crucial role in immunomodulation during pathogenesis. The advantages of extracellular vesicle-based therapies include stability, biocompatibility, low cytotoxicity, and minimal immunogenicity, which highlight their great potential for drug delivery and specific treatments for liver fibrosis. In this review, we summarize the complex biological functions of EVs in the inflammatory response in the pathogenesis of liver fibrosis and evaluate the potential of EVs in the diagnosis and treatment of liver fibrosis.

microRNA associated with hepatocyte injury and systemic inflammation may predict adverse outcomes in cirrhotic patients

As the global prevalence of chronic liver disease continues to rise, the need to determine which patients will develop end-stage liver disease and require liver transplantation is increasingly important. However, current prognostic models perform sub-optimally. We aim to determine microRNA profiles associated with clinical decompensation and mortality/transplantation within 1 year. We examined microRNA expression profiles in plasma samples from patients across the spectrum of cirrhosis (n = 154), acute liver failure (ALF) (n = 22), sepsis (n = 20) and healthy controls (HC) (n = 20). We demonstrated that a microRNA-based model (miR-24 and -27a) associated with systemic inflammation differentiated decompensated cirrhosis states from compensated cirrhosis and HC (AUC 0.77 (95% CI 0.69-0.85)). 6 patients within the compensated cirrhosis group decompensated the subsequent year and their exclusion improved model performance (AUC 0.81 (95% CI 0.71-0.89)). miR-191 (associated with liver injury) predicted risk of mortality across the cohort when acutely decompensated and acute-on-chronic-liver failure patients were included. When they were excluded miR-24 (associated with systemic inflammation) predicted risk of mortality. Our findings demonstrate that microRNA associated with systemic inflammation and liver injury predict adverse outcomes in cirrhosis. miR-24 and -191 require further investigation as prognostic biomarkers and therapeutic targets for patients with liver disease.

Bubbling beyond the barrier: exosomal RNA as a vehicle for soma-germline communication

'Weismann's barrier' has restricted theories of heredity to the transmission of genomic variation for the better part of a century. However, the discovery and elucidation of epigenetic mechanisms of gene regulation such as DNA methylation and histone modifications has renewed interest in studies on the inheritance of acquired traits and given them mechanistic plausibility. Although it is now clear that these mechanisms allow many environmentally acquired traits to be transmitted to the offspring, how phenotypic information is communicated from the body to its gametes has remained a mystery. Here, we discuss recent evidence that such communication is mediated by somatic RNAs that travel inside extracellular vesicles to the gametes where they reprogram the offspring epigenome and phenotype. How gametes learn about bodily changes has implications not only for the clinic, but also for evolutionary theory by bringing together intra- and intergenerational mechanisms of phenotypic plasticity and adaptation.

miRNAs in patients with alcoholic liver disease: a systematic review and meta-analysis

INTRODUCTION

Alcoholic liver disease (ALD) encompasses a spectrum of liver conditions, including liver steatosis, alcoholic hepatitis (AH), fibrosis, cirrhosis, and hepatocellular carcinoma (HCC). microRNAs (miRNAs) have garnered significant interest as potential biomarkers for ALD.

METHODS

We searched PubMed, Embase, Web of Science and Cochrane Central Register of Controlled Trials (CENTRAL) systemically from inception to June 2024. All extracted data was stratified according to the stages of ALD. The vote-counting strategy performed a meta-analysis on miRNA expression profiles.

RESULTS

We included 40 studies. In serum of individuals with alcohol-use vs. no alcohol-use, miRNA-122 and miRNA-155 were upregulated, and miRNA-146a was downregulated. In patients with ALD vs. healthy controls, miRNA-122 and miRNA-155 were also upregulated, and miRNA-146a was downregulated. However, in patients with AH vs. healthy individuals, only the serum miRNA-122 level was upregulated. Due to insufficient data on diagnostic accuracy, we failed to conclude the ability of miRNAs to distinguish between different stages of ALD-related liver fibrosis. The results for ALD-related HCC were also insufficient and controversial.

CONCLUSIONS

Circulating miRNA-122 was the most promising biomarker to manage individuals with ALD. More studies were needed for the diagnostic accuracy of miRNAs in ALD.

REGISTRATION

This protocol was registered on the International Prospective Register of Systematic Reviews (PROSPERO) (www.crd.york.ac.uk/prospero/) with registration number CRD42023391931.

Effect of ethanol exposure on innate immune response in sepsis

Alcohol use disorder, reported by 1 in 8 critically ill patients, is a risk factor for death in sepsis patients. Sepsis, the leading cause of death, kills over 270,000 patients in the United States alone and remains without targeted therapy. Immune response in sepsis transitions from an early hyperinflammation to persistent inflammation and immunosuppression and multiple organ dysfunction during late sepsis. Innate immunity is the first line of defense against pathogen invasion. Ethanol exposure is known to impair innate and adaptive immune response and bacterial clearance in sepsis patients. Specifically, ethanol exposure is known to modulate every aspect of innate immune response with and without sepsis. Multiple molecular mechanisms are implicated in causing dysregulated immune response in ethanol exposure with sepsis, but targeted treatments have remained elusive. In this article, we outline the effects of ethanol exposure on various innate immune cell types in general and during sepsis.

Exosomal miR-223 promotes ARDS by targeting insulin-like growth factor 1 receptor: A cell communication study

BACKGROUND

Acute respiratory distress syndrome (ARDS) is a respiratory failure syndrome characterized by hypoxemia and changes in the respiratory system. ARDS is the most common cause of death in COVID-19 deaths was ARDS. In this study, we explored the role of miR-223 in exosomes in ARDS.

METHODS

Exosomes were purified from the supernatants of macrophages. qPCR was used to detect relative mRNA levels. A luciferase reporter assay was performed to verify the miRNA target genes. Western blotting was used to detect the activation of inflammatory pathways. Flow cytometry was performed to assess apoptosis. An LPS-induced ARDS mouse model was used to assess the function of miR-223 in ARDS.

RESULTS

Exosomes secreted by macrophages promoted apoptosis in A549 cells. Macrophages and exosomes contain high levels of miR-223. Exogenous miR-223 can decrease the expression of insulin-like growth factor 1 receptor (IGF-1R) in A549 and promote the apoptosis of A549.Transfection of anti-miR223 antisense nucleotides effectively reduced the level of miR-223 in macrophages and exosomes and eliminated the pro-apoptotic effect of A549. In vivo, LPS stimulation increased inflammatory cell infiltration in the lungs of mice, whereas knockdown of miR-223 in mice resulted in significantly reduced eosinophil infiltration.

CONCLUSIONS

Macrophages can secrete exosomes containing miR-223 and promote apoptosis by targeting the IGF-1R/Akt/mTOR signaling pathway in A549 cells and mouse models, suggesting that miR-223 is a potential target for treating COVID-19 induced ARDS.

The challenges and potential of microRNA-based therapy for patients with liver failure syndromes and hepatocellular carcinoma

INTRODUCTION

Morbidity and mortality from liver disease continues to rise worldwide. There are currently limited curative treatments for patients with liver failure syndromes, encompassing acute liver failure and decompensated cirrhosis states, outside of transplantation. Whilst there have been improvements in therapeutic options for patients with hepatocellular carcinoma (HCC), there remain challenges necessitating novel therapeutic agents. microRNA have long been seen as potential therapeutic targets but there has been limited clinical translation.

AREAS COVERED

We will discuss the limitations of conventional non-transplant management of patients with liver failure syndromes and HCC. We will provide an overview of microRNA and the challenges in developing and delivering microRNA-based therapeutic agents. We will finally provide an overview of microRNA-based therapeutic agents which have progressed to clinical trials.

EXPERT OPINION

microRNA have great potential to be developed into therapeutic agents due to their association with critical biological processes which govern health and disease. Utilizing microRNA sponges to target multiple microRNA associated with specific biological processes may improve their therapeutic efficacy. However, there needs to be significant improvements in delivery systems to ensure the safe delivery of microRNA to target sites and minimize systemic distribution. This currently significantly impacts the clinical translation of microRNA-based therapeutic agents.

Impact of Alcohol on Inflammation, Immunity, Infections, and Extracellular Vesicles in Pathogenesis

Alcohol consumption is a widespread social activity with a complex and multifaceted impact on human health. Although moderate alcohol consumption has been associated with certain potential health benefits, excessive or chronic alcohol use can disrupt the body's immune balance, promote inflammation, and increase susceptibility to infections. The deleterious effects associated with alcohol toxicity include the loss of cell integrity. When cells lose their integrity, they also lose the capacity to communicate with other systems. One of the systems disturbed by alcohol toxicity is extracellular vesicle (EV)-mediated communication. EVs are critical mediators of cell-to-cell communication. They play a significant role in alcohol-induced pathogenesis, facilitating communication and molecular exchange between cells, thereby potentially contributing to alcohol-related health issues. Investigating their involvement in this context is fundamental to resolving the intricate mechanisms behind the health consequences of alcohol use and may pave the way for innovative approaches for mitigating the adverse effects of alcohol on immune health. Understanding the role of EVs in the context of alcohol-induced pathogenesis is essential for comprehending the mechanisms behind alcohol-related health issues.

Extracellular Vesicles as Delivery Vehicles for Non-Coding RNAs: Potential Biomarkers for Chronic Liver Diseases

In recent years, EVs have emerged as promising vehicles for coding and non-coding RNAs (ncRNAs), which have demonstrated remarkable potential as biomarkers for various diseases, including chronic liver diseases (CLDs). EVs are small, membrane-bound particles released by cells, carrying an arsenal of ncRNAs, including microRNAs (miRNAs), long non-coding RNAs (lncRNAs), and other ncRNA species, such as piRNAs, circRNAs, and tsRNAs. These ncRNAs act as key regulators of gene expression, splicing, and translation, providing a comprehensive molecular snapshot of the cells of origin. The non-invasive nature of EV sampling, typically via blood or serum collection, makes them highly attractive candidates for clinical biomarker applications. Moreover, EV-encapsulated ncRNAs offer unique advantages over traditional cell-free ncRNAs due to their enhanced stability within the EVs, hence allowing for their detection in circulation for extended periods and enabling more sensitive and reliable biomarker measurements. Numerous studies have investigated the potential of EV-enclosed ncRNAs as biomarkers for CLD. MiRNAs, in particular, have gained significant attention due to their ability to rapidly respond to changes in cellular stress and inflammation, hallmarks of CLD pathogenesis. Elevated levels of specific miRNAs have been consistently associated with various CLD subtypes, including metabolic dysfunction-associated steatotic liver disease (MASLD), metabolic dysfunction-associated steatohepatitis (MASH), and chronic hepatitis B and C. LncRNAs have also emerged as promising biomarkers for CLD. These transcripts are involved in a wide range of cellular processes, including liver regeneration, fibrosis, and cancer progression. Studies have shown that lncRNA expression profiles can distinguish between different CLD subtypes, providing valuable insights into disease progression and therapeutic response. Promising EV-enclosed ncRNA biomarkers for CLD included miR-122 (elevated levels of miR-122 are associated with MASLD progression and liver fibrosis), miR-21 (increased expression of miR-21 is linked to liver inflammation and fibrosis in CLD patients), miR-192 (elevated levels of miR-192 are associated with more advanced stages of CLD, including cirrhosis and HCC), LncRNA HOTAIR (increased HOTAIR expression is associated with MASLD progression and MASH development), and LncRNA H19 (dysregulation of H19 expression is linked to liver fibrosis and HCC progression). In the present review, we focus on the EV-enclosed ncRNAs as promising tools for the diagnosis and monitoring of CLD of various etiologies.

Advances in 3D Culture Models to Study Exosomes in Triple-Negative Breast Cancer

Breast cancer, a leading cause of cancer-related deaths globally, exhibits distinct subtypes with varying pathological, genetic, and clinical characteristics. Despite advancements in breast cancer treatments, its histological and molecular heterogeneity pose a significant clinical challenge. Triple-negative breast cancer (TNBC), a highly aggressive subtype lacking targeted therapeutics, adds to the complexity of breast cancer treatment. Recent years have witnessed the development of advanced 3D culture technologies, such as organoids and spheroids, providing more representative models of healthy human tissue and various malignancies. These structures, resembling organs in structure and function, are generated from stem cells or organ-specific progenitor cells via self-organizing processes. Notably, 3D culture systems bridge the gap between 2D cultures and in vivo studies, offering a more accurate representation of in vivo tumors' characteristics. Exosomes, small nano-sized molecules secreted by breast cancer and stromal/cancer-associated fibroblast cells, have garnered significant attention. They play a crucial role in cell-to-cell communication, influencing tumor progression, invasion, and metastasis. The 3D culture environment enhances exosome efficiency compared to traditional 2D cultures, impacting the transfer of specific cargoes and therapeutic effects. Furthermore, 3D exosomes have shown promise in improving therapeutic outcomes, acting as potential vehicles for cancer treatment administration. Studies have demonstrated their role in pro-angiogenesis and their innate therapeutic potential in mimicking cellular therapies without side effects. The 3D exosome model holds potential for addressing challenges associated with drug resistance, offering insights into the mechanisms underlying multidrug resistance and serving as a platform for drug screening. This review seeks to emphasize the crucial role of 3D culture systems in studying breast cancer, especially in understanding the involvement of exosomes in cancer pathology.

Emergence of Extracellular Vesicles as "Liquid Biopsy" for Neurological Disorders: Boom or Bust

Extracellular vesicles (EVs) have emerged as an attractive liquid biopsy approach in the diagnosis and prognosis of multiple diseases and disorders. The feasibility of enriching specific subpopulations of EVs from biofluids based on their unique surface markers has opened novel opportunities to gain molecular insight from various tissues and organs, including the brain. Over the past decade, EVs in bodily fluids have been extensively studied for biomarkers associated with various neurological disorders, such as Alzheimer's disease, Parkinson's disease, schizophrenia, bipolar disorder, major depressive disorders, substance use disorders, human immunodeficiency virus-associated neurocognitive disorder, and cancer/treatment-induced neurodegeneration. These studies have focused on the isolation and cargo characterization of either total EVs or brain cells, such as neuron-, astrocyte-, microglia-, oligodendrocyte-, pericyte-, and endothelial-derived EVs from biofluids to achieve early diagnosis and molecular characterization and to predict the treatment and intervention outcomes. The findings of these studies have demonstrated that EVs could serve as a repetitive and less invasive source of valuable molecular information for these neurological disorders, supplementing existing costly neuroimaging techniques and relatively invasive measures, like lumbar puncture. However, the initial excitement surrounding blood-based biomarkers for brain-related diseases has been tempered by challenges, such as lack of central nervous system specificity in EV markers, lengthy protocols, and the absence of standardized procedures for biological sample collection, EV isolation, and characterization. Nevertheless, with rapid advancements in the EV field, supported by improved isolation methods and sensitive assays for cargo characterization, brain cell-derived EVs continue to offer unparallel opportunities with significant translational implications for various neurological disorders. SIGNIFICANCE STATEMENT: Extracellular vesicles present a less invasive liquid biopsy approach in the diagnosis and prognosis of various neurological disorders. Characterizing these vesicles in biofluids holds the potential to yield valuable molecular information, thereby significantly impacting the development of novel biomarkers for various neurological disorders. This paper has reviewed the methodology employed to isolate extracellular vesicles derived from various brain cells in biofluids, their utility in enhancing the molecular understanding of neurodegeneration, and the potential challenges in this research field.

Extracellular vesicles as tools and targets in therapy for diseases

Extracellular vesicles (EVs) are nano-sized, membranous structures secreted into the extracellular space. They exhibit diverse sizes, contents, and surface markers and are ubiquitously released from cells under normal and pathological conditions. Human serum is a rich source of these EVs, though their isolation from serum proteins and non-EV lipid particles poses challenges. These vesicles transport various cellular components such as proteins, mRNAs, miRNAs, DNA, and lipids across distances, influencing numerous physiological and pathological events, including those within the tumor microenvironment (TME). Their pivotal roles in cellular communication make EVs promising candidates for therapeutic agents, drug delivery systems, and disease biomarkers. Especially in cancer diagnostics, EV detection can pave the way for early identification and offers potential as diagnostic biomarkers. Moreover, various EV subtypes are emerging as targeted drug delivery tools, highlighting their potential clinical significance. The need for non-invasive biomarkers to monitor biological processes for diagnostic and therapeutic purposes remains unfulfilled. Tapping into the unique composition of EVs could unlock advanced diagnostic and therapeutic avenues in the future. In this review, we discuss in detail the roles of EVs across various conditions, including cancers (encompassing head and neck, lung, gastric, breast, and hepatocellular carcinoma), neurodegenerative disorders, diabetes, viral infections, autoimmune and renal diseases, emphasizing the potential advancements in molecular diagnostics and drug delivery.

MicroRNA miR-27a as a possible regulator of anti-inflammatory macrophage phenotype in preeclamptic placenta

INTRODUCTION

The role of the TGFβ signaling pathway, an important cascade responsible for the anti-inflammatory polarization of macrophages, in the development of both early- and late-onset preeclampsia (eoPE and loPE), remains poorly understood. In this study, we examined the components of the TGFβ signaling cascade and macrophage markers within placental tissue in normal pregnancy and in PE.

METHODS

Patients with eoPE, loPE, and normal pregnancy were enrolled in the study (n = 10 in each group). Following techniques were used for the investigation: immunohistochemistry analysis, western blotting, qRT-PCR, isolation of monocytes by magnetic sorting, transfection, microRNA sequencing, and bioinformatic analysis.

RESULTS

We observed a significant decrease in the anti-inflammatory macrophage marker CD206 in the loPE group, alongside with a significant down-regulation of CD206 protein production in both eoPE and loPE groups. The level of CD68-positive cells and relative levels of CD163 and MARCO production were comparable across the groups. However, we identified a significant decrease in the TGFβ receptor 2 production and its gene expression in the PE group. Further analysis revealed a link between TGFBR2 and MRC1 (CD206) genes through a single miRNA, hsa-miR-27a-3p. Transfecting CD14-derived macrophages with the hsa-miR-27a-3p mimic significantly changed TGFBR2 production, indicating the potential role of this miRNA in regulating the TGFβ signaling pathway. We also revealed the up-regulation of hsa-miR-27a-5p and hsa-miR-27a-3p in the trophoblast BeWo b30 cell line under the severe hypoxia condition and the fact that TGFBR2 3' UTR could serve as a potential target for these miRNAs.

DISCUSSION

Our findings uncover a novel potential therapeutic target for managing patients with PE, significantly contributing to a deeper comprehension of the underlying mechanisms involved in the development of this pathology.

The challenges and potential in developing microRNA associated with regeneration as biomarkers to improve prognostication for liver failure syndromes and hepatocellular carcinoma

INTRODUCTION

Determining the need for liver transplantation remains critical in the management of hepatocellular carcinoma (HCC) and liver failure syndromes (including acute liver failure and decompensated cirrhosis states). Conventional prognostic models utilize biomarkers of liver and non-liver failure and have limitations in their application. Novel biomarkers which predict regeneration may fulfil this niche. microRNA are implicated in health and disease and are present in abundance in the circulation. Despite this, they have not translated into mainstream clinical biomarkers.

AREAS COVERED

We will discuss current challenges in the prognostication of patients with liver failure syndromes as well as for patients with HCC. We will discuss biomarkers implicated with liver regeneration. We then provide an overview of the challenges in developing microRNA into clinically tractable biomarkers. Finally, we will provide a scoping review of microRNA which may have potential as prognostic biomarkers in liver failure syndromes and HCC.

EXPERT OPINION

Novel biomarkers are needed to improve prognostic models in liver failure syndromes and HCC. Biomarkers associated with liver regeneration are currently lacking and may fulfil this niche. microRNA have the potential to be developed into clinically tractable biomarkers but a consensus on standardizing methodology and reporting is required prior to large-scale studies.

Single-cell transcriptomics of peripheral blood mononuclear cells indicates impaired immune and inflammatory responses in alcohol-associated hepatitis

Alcohol-associated hepatitis (AH) is often diagnosed at advanced stages, and severe AH usually carries poor prognosis and high short-term mortality. In addition, it is challenging to understand the molecular mechanisms of immune dysregulation and inflammation in AH due to the cellular complexity and heterogeneity. Using single-cell RNA sequencing, previous studies found that AH causes dysfunctional innate immune response in monocytes, involving activation of pattern recognition receptors (PRRs) and cytokine signaling pathways. To better understand the coordinated systemic immune response in AH patients, we performed combined single-cell transcriptome, cell-surface protein, and lymphocyte antigen receptor analysis of peripheral blood mononuclear cell (PBMC) samples. Our results showed inflammatory cytokines and chemokines were highly expressed in AH, including IL-2, IL-32, CXC3R1 and CXCL16 in monocytes and NK cells, whereas HLA-DR genes were reduced in monocytes. In addition, we also found altered differentiation of T-helper cells (TH1 and TH17), which could further lead to neutrophil recruitment and macrophage activation. Lastly, our results also suggest impaired NK-cell activation and differentiation in AH with reduced gene expression of KLRC2 and increased gene expression of KLRG1. Our findings indicate different mechanisms may be involved in impaired immune and inflammatory responses for the cellular subtypes of the PBMCs in AH.

Liquid Liver Biopsy for Disease Diagnosis and Prognosis

Liver diseases are a major burden worldwide, the scope of which is expected to further grow in the upcoming years. Clinically relevant liver dysfunction-related blood markers such as alanine aminotransferase and aspartate aminotransferase have limited accuracy. Nowadays, liver biopsy remains the gold standard for several liver-related pathologies, posing a risk of complication due to its invasive nature. Liquid biopsy is a minimally invasive approach, which has shown substantial potential in the diagnosis, prognosis, and monitoring of liver diseases by detecting disease-associated particles such as proteins and RNA molecules in biological fluids. Histones are the core components of the nucleosomes, regulating essential cellular processes, including gene expression and DNA repair. Following cell death or activation of immune cells, histones are released in the extracellular space and can be detected in circulation. Histones are stable in circulation, have a long half-life, and retain their post-translational modifications. Here, we provide an overview of the current research on histone-mediated liquid biopsy methods for liver diseases, with a focus on the most common detection methods.

Function of macrophage-derived exosomes in chronic liver disease: From pathogenesis to treatment

Chronic liver disease (CLD) imposes a heavy burden on millions of people worldwide. Despite substantial research on the pathogenesis of CLD disorders, no optimal treatment is currently available for some diseases, such as liver cancer. Exosomes, which are extracellular vesicles, are composed of various cellular components. Exosomes have unique functions in maintaining cellular homeostasis and regulating cell communication, which are associated with the occurrence of disease. Furthermore, they have application potential in diagnosis and treatment by carrying diverse curative payloads. Hepatic macrophages, which are key innate immune cells, show extraordinary heterogeneity and polarization. Hence, macrophage-derived exosomes may play a pivotal role in the initiation and progression of various liver diseases. This review focuses on the effects of macrophage-derived exosomes on liver disease etiology and their therapeutic potential, which will provide new insights into alleviating the global pressure of CLD.

MiRNAs in Alcohol-Related Liver Diseases and Hepatocellular Carcinoma: A Step toward New Therapeutic Approaches?

Alcohol-related Liver Disease (ALD) is the primary cause of chronic liver disorders and hepatocellular carcinoma (HCC) development in developed countries and thus represents a major public health concern. Unfortunately, few therapeutic options are available for ALD and HCC, except liver transplantation or tumor resection for HCC. Deciphering the molecular mechanisms underlying the development of these diseases is therefore of major importance to identify early biomarkers and to design efficient therapeutic options. Increasing evidence indicate that epigenetic alterations play a central role in the development of ALD and HCC. Among them, microRNA importantly contribute to the development of this disease by controlling the expression of several genes involved in hepatic metabolism, inflammation, fibrosis, and carcinogenesis at the post-transcriptional level. In this review, we discuss the current knowledge about miRNAs' functions in the different stages of ALD and their role in the progression toward carcinogenesis. We highlight that each stage of ALD is associated with deregulated miRNAs involved in hepatic carcinogenesis, and thus represent HCC-priming miRNAs. By using in silico approaches, we have uncovered new miRNAs potentially involved in HCC. Finally, we discuss the therapeutic potential of targeting miRNAs for the treatment of these diseases.

The promise of small particles: extracellular vesicles as biomarkers in liver pathology

Extracellular vesicles (EVs) are nanoscopic packages that are heterogeneous and bona fide players in hepatic physiology and pathology as they are involved in intercellular communication. EVs carrying bioactive cargoes rich in lipids, proteins or nucleic acids are implicated in the onset and progression of liver diseases. Liver pathology using liver biopsy has been assessed for several intricate conditions such as viral hepatitis, alcoholic and non-alcoholic fatty liver disease, hepatic malignancies and drug-induced liver injury. The lacunae, however, lie in early diagnosis and timely treatment of the above conditions, underscoring the need for non-invasive, accurate diagnostic tools that could replace the gold standard method of tissue biopsy. In this regard, EVs have emerged as promising candidates that could serve as potential biomarkers. In the last two decades, EVs, owing to their multifaceted charm in bringing out cell-free therapeutic responses and the ability of their cargoes to be applied to novel biomarkers, have drawn the great attention of researchers with the advancement and clinical application of liquid biopsy. In this review, we recapitulate the role of EVs and provide insights into the promising role of these small packages as biomarkers in liver pathology.

Unraveling the Complex Interplay between Epigenetics and Immunity in Alcohol-Associated Liver Disease: A Comprehensive Review

The mechanisms of immune dysfunction in alcohol-associated liver disease (ALD) have garnered growing research interest in recent times. Alcohol-mediated immune dysfunction has been implicated as a potential cause of ALD-associated microbial infection and inflammatory response. The immune microenvironment of an organism is essentially a complex network of interactions between immune cells, cytokines, extracellular matrix, and other immune-related molecules. This microenvironment is highly adaptive and responsive to environmental cues. Epigenetic reprogramming of the immune microenvironment has recently emerged as a key driver of ALD progression, particularly in the context of endotoxin tolerance and immune disorders. Although epigenetic modifications are known to play an important role in the regulation of the immune microenvironment in ALD, the specific mechanisms and molecular processes by which this regulation is achieved are yet to be fully understood. This paper aims to provide an overview of the current knowledge on the effects of alcohol consumption on epigenetics, with special focus on summarizing the data on the epigenetic regulatory mechanisms involved in the effects of alcohol consumption on the immune microenvironment. In addition, this paper aims to present a review of the epigenetic modifications involved in different forms of ALD. This review is expected to offer new perspectives for the diagnosis, treatment, monitoring, and prognostic assessment of ALD from an epigenetic perspective.

Enhanced bioprocess control to advance the manufacture of mesenchymal stromal cell-derived extracellular vesicles in stirred-tank bioreactors

Extracellular vesicles (EVs) derived from mesenchymal stromal cells (MSCs) act as signaling mediators of cellular responses. However, despite representing a promising alternative to cell-based therapies, clinical translation of EVs is currently limited by their lack of scalability and standardized bioprocessing. Herein, we integrated scalable downstream processing protocols with standardized expansion of large numbers of viable cells in stirred-tank bioreactors to improve EV production. Higher EV yields were linked to EV isolation by tangential flow filtration followed by size exclusion chromatography, rendering 5 times higher number of EVs comparatively to density gradient ultracentrifugation protocols. Additionally, when compared to static culture, EV manufacture in bioreactors resulted in 2.2 higher yields. Highlighting the role of operating under optimal cell culture conditions to maximize the number of EVs secreted per cell, MSCs cultured at lower glucose concentration favored EV secretion. While offline measurements of metabolites concentration can be performed, in this work, Raman spectroscopy was also applied to continuously track glucose levels in stirred-tank bioreactors, contributing to streamline the selection of optimal EV collection timepoints. Importantly, MSC-derived EVs retained their quality attributes and were able to stimulate angiogenesis in vitro, therefore highlighting their promising therapeutic potential.

Detrimental Effects of Alcohol-Induced Inflammation on Brain Health: From Neurogenesis to Neurodegeneration

Alcohol consumption is known to cause several brain anomalies. The pathophysiological changes associated with alcohol intoxication are mediated by various factors, most notable being inflammation. Alcohol intoxication may cause inflammation through several molecular mechanisms in multiple organs, including the brain, liver and gut. Alcohol-induced inflammation in the brain and gut are intricately connected. In the gut, alcohol consumption leads to the weakening of the intestinal barrier, resulting in bacteria and bacterial endotoxins permeating into the bloodstream. These bacterial endotoxins can infiltrate other organs, including the brain, where they cause cognitive dysfunction and neuroinflammation. Alcohol can also directly affect the brain by activating immune cells such as microglia, triggering the release of pro-inflammatory cytokines and neuroinflammation. Since alcohol causes the death of neural cells, it has been correlated to an increased risk of neurodegenerative diseases. Besides, alcohol intoxication has also negatively affected neural stem cells, affecting adult neurogenesis and causing hippocampal dysfunctions. This review provides an overview of alcohol-induced brain anomalies and how inflammation plays a crucial mechanistic role in alcohol-associated pathophysiology.

Manufacture of extracellular vesicles derived from mesenchymal stromal cells

Mesenchymal stromal cells (MSCs) are a promising therapy for various diseases ranging from ischemic stroke to wound healing and cancer. Their therapeutic effects are mainly mediated by secretome-derived paracrine factors, with extracellular vesicles (EVs) proven to play a key role. This has led to promising research on the potential of MSC-EVs as regenerative, off-the-shelf therapeutic agents. However, the translation of MSC-EVs into the clinic is hampered by the poor scalability of their production. Recently, new advanced methods have been developed to upscale MSC cultivation and EV production yields, ranging from new cell culture devices to priming procedures. This review gives an overview of these innovative strategies for manufacturing MSC-EVs.

Differential expression of adipocyte and myotube extracellular vesicle miRNA cargo in chronic binge alcohol-administered SIV-infected male macaques

Our studies in chronic binge alcohol (CBA) -treated simian immunodeficiency virus (SIV)-infected macaques and in people living with HIV (PLWH) show significant alterations in metabolic homeostasis. CBA promotes a profibrotic phenotype in adipose tissue and skeletal muscle (SKM) and decreases adipose-derived stem cell and myoblast differentiation, making adipose and SKM potential drivers in metabolic dysregulation. Furthermore, we have shown that the differential expression of microRNAs (miRs) in SKM contributes to impaired myoblast differentiation potential. Beyond modulation of intracellular responses, miRs can be transported in extracellular vesicles (EVs) to mediate numerous cellular responses through intercellular and interorgan communication. This study tested the hypothesis that CBA alters concentration and miR cargo of EVs derived from adipocytes and myotubes isolated from SIV-infected male macaques. Fourteen male rhesus macaques received either CBA (2.5 g/kg/day) or sucrose (VEH) for 14.5 months. Three months following the initiation of CBA/VEH, all animals were infected with SIVmac251 and 2.5 months later were initiated on antiretroviral therapy. SKM and adipose tissue samples were collected at the study endpoint (blood alcohol concentration = 0 mM). EVs were isolated by ultracentrifugation of myotube and adipocyte cell culture supernatant. Nanoparticle tracking revealed no differences in concentration or size of particles between VEH and CBA groups. Adipocyte-derived EVs from CBA animals showed decreased miR-let-7a expression (p = 0.03). Myotube-derived EVs from CBA animals had decreased miR-16 (p = 0.04) and increased miR-133a and miR-133b (both p = 0.04) expression. These results indicate that CBA administration differentially regulates EV miR content but does not alter the number of EVs from adipocytes or myotubes. Future studies are warranted to determine the functional relevance of CBA-altered EV miR cargo and their role in intercellular and interorgan communication and metabolic dysregulation.

Exosomes: Nomenclature, Isolation, and Biological Roles in Liver Diseases

The biogenesis and biological roles of extracellular vesicles (EVs) in the progression of liver diseases have attracted considerable attention in recent years. EVs are membrane-bound nanosized vesicles found in different types of body fluids and contain various bioactive materials, including proteins, lipids, nucleic acids, and mitochondrial DNA. Based on their origin and biogenesis, EVs can be classified as apoptotic bodies, microvesicles, and exosomes. Among these, exosomes are the smallest EVs (30-150 nm in diameter), which play a significant role in cell-to-cell communication and epigenetic regulation. Moreover, exosomal content analysis can reveal the functional state of the parental cell. Therefore, exosomes can be applied to various purposes, including disease diagnosis and treatment, drug delivery, cell-free vaccines, and regenerative medicine. However, exosome-related research faces two major limitations: isolation of exosomes with high yield and purity and distinction of exosomes from other EVs (especially microvesicles). No standardized exosome isolation method has been established to date; however, various exosome isolation strategies have been proposed to investigate their biological roles. Exosome-mediated intercellular communications are known to be involved in alcoholic liver disease and nonalcoholic fatty liver disease development. Damaged hepatocytes or nonparenchymal cells release large numbers of exosomes that promote the progression of inflammation and fibrogenesis through interactions with neighboring cells. Exosomes are expected to provide insight on the progression of liver disease. Here, we review the biogenesis of exosomes, exosome isolation techniques, and biological roles of exosomes in alcoholic liver disease and nonalcoholic fatty liver disease.

Role of Extracellular Vesicles in Liver Diseases

Extracellular vesicles (EVs) are cell-derived membrane structures that are formed by budding from the plasma membrane or originate from the endosomal system. These microparticles (100 nm-100 µm) or nanoparticles (>100 nm) can transport complex cargos to other cells and, thus, provide communication and intercellular regulation. Various cells, such as hepatocytes, liver sinusoidal endothelial cells (LSECs) or hepatic stellate cells (HSCs), secrete and take up EVs in the healthy liver, and the amount, size and content of these vesicles are markedly altered under pathophysiological conditions. A comprehensive knowledge of the modified EV-related processes is very important, as they are of great value as biomarkers or therapeutic targets. In this review, we summarize the latest knowledge on hepatic EVs and the role they play in the homeostatic processes in the healthy liver. In addition, we discuss the characteristic changes of EVs and their potential exacerbating or ameliorating effects in certain liver diseases, such as non-alcoholic fatty liver disease (NAFLD), alcoholic fatty liver disease (AFLD), drug induced liver injury (DILI), autoimmune hepatitis (AIH), hepatocarcinoma (HCC) and viral hepatitis.

Extracellular vesicles: an emerging player in retinal homeostasis

Extracellular vesicles (EVs) encompass secreted membrane vesicles of varied sizes, including exosomes (-30-200 nm) and microvesicles (MVs) that are ∼100-1,000 nm in size. EVs play an important role in autocrine, paracrine, and endocrine signaling and are implicated in myriad human disorders including prominent retinal degenerative diseases, like age related macular degeneration (AMD) and diabetic retinopathy (DR). Studies of EVs in vitro using transformed cell lines, primary cultures, and more recently, induced pluripotent stem cell derived retinal cell type(s) (e.g., retinal pigment epithelium) have provided insights into the composition and function of EVs in the retina. Furthermore, consistent with a causal role of EVs in retinal degenerative diseases, altering EV composition has promoted pro-retinopathy cellular and molecular events in both in vitro and in vivo models. In this review, we summarize the current understanding of the role of EVs in retinal (patho)physiology. Specifically, we will focus on disease-associated EV alterations in specific retinal diseases. Furthermore, we discuss the potential utility of EVs in diagnostic and therapeutic strategies for targeting retinal diseases.

A comprehensive multiparameter flow cytometry panel for immune profiling and functional studies of frozen tissue, bone marrow, and spleen

Flow cytometry (FC) is a highly informative technology that can provide valuable information about immune phenotype monitoring and immune cell states. However, there is a paucity of comprehensive panels developed and validated for use on frozen samples. Here, we developed a 17-plex flow cytometry panel to detect subtypes, frequencies, and functions of different immune cells that can be leveraged to study the different cellular characteristics in different disease models, physiological, and pathological conditions. This panel identifies surface markers to characterize T cells (CD8+, CD4+), natural killer (NK) cells and their subtypes (immature, cytotoxic, exhausted, activated),natural killer T (NKT) cells, neutrophils, macrophages (M1 (pro-inflammatory) and M2 (anti-inflammatory)), monocytes and their subtypes (classical and non-classical), dendritic cells (DC) and their subtypes (DC1, DC2), and eosinophils. The panel was designed to include only surface markers to avoid the necessity for fixation and permeabilization steps. This panel was optimized using cryopreserved cells. Immunophenotyping of spleen and bone marrow using the proposed panel was efficient in correctly differentiating the immune cell subtypes in inflammatory model of ligature-induced periodontitis, in which we found increased percentage of NKT cells, activated and mature/cytotoxic NK cells in the bone marrow of affected mice. This panel enables in-depth immunophenotyping of murine immune cells in bone marrow, spleen, tumors, and other non-immune tissues of mice. It could be a tool for systematic analysis of immune cell profiling in inflammatory conditions, systemic diseases, and tumor microenvironments.

miR-27a-5p inhibits acute rejection of liver transplantation in rats by inducing M2 polarization of Kupffer cells through the PI3K/Akt pathway

Liver transplantation (LT), a major therapy for end-stage liver disease, is often associated with acute rejection (AR). MicroRNAs (miRNAs) have been implicated in AR-related gene regulation. In this experiment, the mechanism of miR-27a-5p in AR of LT was studied. Allotransplantation model (LEW-BN) and syngeneic transplantation model (LEW-LEW) of rat orthotopic liver transplantation (OLT) were established. miR-27a-5p was overexpressed in recipient rats 28 days before LT to detect its effects on LT pathology, liver function, and survival time. Kupffer cells (KCs) were isolated and treated with lipopolysaccharide (LPS) and miR-27a-5p overexpression. miR-27a-5p overexpression reduced lymphocyte numbers around portal areas and central veins after LT and mitigated degeneration of epithelial cells of the bile duct. Expression levels of IL-10 and TGF-β1 were increased while IL-12 was decreased. Liver function damage was alleviated and the survival time of rats with LT was prolonged. miR-27a-5p induced M2 polarization of rats with AR after LT and LPS-treated KCs in vitro and promoted activation of the PI3K/Akt pathway in KCs. Inhibition of the PI3K/Akt pathway averted induction of miR-27a-5p on M2 polarization of KCs. Taken together, miR-27a-5p inhibited AR after LT in rats by inducing M2 polarization of KCs through the PI3K/Akt pathway.

Extracellular vesicles in fatty liver disease and steatohepatitis: Role as biomarkers and therapeutic targets

Non-alcoholic fatty liver disease (NAFLD) and alcohol-associated liver disease (ALD) are characterized by lipid deposition in hepatocytes in the absence or presence of excessive alcohol consumption, respectively, ranging from simple steatosis to non-alcoholic steatohepatitis (NASH) or alcoholic hepatitis (AH) and from mild fibrosis to cirrhosis. Fatty liver disease and steatohepatitis similarly occur in individuals who have both metabolic syndrome and excessive alcohol intake; therefore, the single overarching term metabolic associated fatty liver disease (MAFLD) has been proposed to better reflect these risk factors and the continuity of disease progression. Extracellular vesicles (EVs) are membrane-bound endogenous nanoparticles released into the extracellular space by a majority of cell types. Liver disease-related EVs contain a variety of cellular cargo and are internalized into target cells resulting in the transfer of bioinformation reflecting the state of the donor cell to the recipient. Furthermore, EV composition can be used to identify the degree and type of liver disease, suggesting that EV composition may be a useful biomarker. With regard to MAFLD, the presence of metabolic risk factors, such as insulin resistance, will be indicated by adipose tissue-derived EVs and with that comes the potential to use as a clinical monitor of overall metabolic status. However, the inhibition of specific EV composition may be difficult to implement as a real-world therapeutic approach. Current global evidence shows that mesenchymal stem cell (MSCs)-derived EVs (MSC-EVs) play an important role in regulating the immune response, which has spawned a clinical trial to treat liver disease.

Effect of Ethanol on Exosome Biogenesis: Possible Mechanisms and Therapeutic Implications

Most eukaryotic cells, including hepatocytes, secrete exosomes into the extracellular space, which are vesicles facilitating horizontal cell-to-cell communication of molecular signals and physiological cues. The molecular cues for cellular functions are carried by exosomes via specific mRNAs, microRNAs, and proteins. Exosomes released by liver cells are a vital part of biomolecular communication in liver diseases. Importantly, exosomes play a critical role in mediating alcohol-associated liver disease (ALD) and are potential biomarkers for ALD. Moreover, alcohol exposure itself promotes exosome biogenesis and release from the livers of humans and rodent models. However, the mechanisms by which alcohol promotes exosome biogenesis in hepatocytes are still unclear. Of note, alcohol exposure leads to liver injury by modulating various cellular processes, including autophagy, ER stress, oxidative stress, and epigenetics. Evidence suggests that there is a link between each of these processes with exosome biogenesis. The aim of this review article is to discuss the interplay between ethanol exposure and these altered cellular processes in promoting hepatocyte exosome biogenesis and release. Based on the available literature, we summarize and discuss the potential mechanisms by which ethanol induces exosome release from hepatocytes, which in turn leads to the progression of ALD.

Extracellular Vesicles and Fatty Liver

Fatty liver is a complex pathological process caused by multiple etiologies. In recent years, the incidence of fatty liver has been increasing year by year, and it has developed into a common chronic disease that seriously affects people's health around the world. It is an important risk factor for liver cirrhosis, liver cancer, and a variety of extrahepatic chronic diseases. Therefore, the early diagnosis and early therapy of fatty liver are important. Except for invasive liver biopsy, there is still a lack of reliable diagnosis and staging methods. Extracellular vesicles are small double-layer lipid membrane vesicles derived from most types of cells. They play an important role in intercellular communication and participate in the occurrence and development of many diseases. Since extracellular vesicles can carry a variety of biologically active substances after they are released by cells, they have received widespread attention. The occurrence and development of fatty liver are also closely related to extracellular vesicles. In addition, extracellular vesicles are expected to provide a new direction for the diagnosis of fatty liver. This article reviews the relationship between extracellular vesicles and fatty liver, laying a theoretical foundation for the development of new strategies for the diagnosis and therapy of fatty liver.

microRNAs-based diagnostic and therapeutic applications in liver fibrosis

Liver fibrosis is a process of over-extracellular matrix (ECM) aggregation and angiogenesis, which develops into cirrhosis and hepatocellular carcinoma (HCC). With the increasing pressure of liver fibrosis, new therapeutics to cure this disease requires much attention. Exosome-cargoed microRNAs (miRNAs) are emerging approaches in the precision of the liver fibrotic paradigm. In this review, we outlined the different types of hepatic cells derived miRNAs that drive intra-/extra-cellular interactive communication in liver fibrosis with different physiological and pathological processes. Specifically, we highlighted the possible mechanism of liver fibrosis pathogenesis associated with immune response and angiogenesis. In addition, potential clinical biomarkers and different stem cell transplant-derived miRNAs-based therapeutic strategies in liver fibrosis were summarized in this review. miRNAs-based approaches might help researchers devise new candidates for the cell-free treatment of liver fibrosis. This article is categorized under: RNA in Disease and Development > RNA in Disease.

Production and Biological Effects of Extracellular Vesicles from Adipose-Derived Stem Cells Were Markedly Increased by Low-Intensity Ultrasound Stimulation for Promoting Diabetic Wound Healing

Diabetic wound treatment has posed a significant challenge in clinical practice. As a kind of cell-derived nanoparticles, extracellular vesicles produced by adipose-derived stem cells (ADSC-EVs) have been reported to be potential agents for diabetic wound treatment. However, ADSC-EV yield is insufficient to meet the demands of clinical therapy. In this study, a novel method involving the use of low-intensity ultrasound stimulation on ADSCs is developed to promote EV secretion for clinical use. A proper low-intensity ultrasound stimulation parameter which significantly increases ADSC-EV quantity has been found. In addition, EVs secreted by ADSCs following low-intensity ultrasound stimulation (US-EVs) are enriched in wound healing-related miRNAs. Moreover, US-EVs promote the biological functions of fibroblasts, keratinocytes, and endothelial cells in vitro, and promote diabetic wound healing in db/db mice in vivo through re-epithelialization, collagen production, cell proliferation, keratinocyte differentiation and migration, and angiogenesis. This study proposes low-intensity ultrasound stimulation as a new method for promoting significant EV secretion by ADSCs and for improving the diabetic wound-healing potential of EVs, which will meet the clinical needs for these nanoparticles. The production of extracellular vesicles of adipose-derived stem cells is obviously promoted by a low-intensity ultrasound stimulation method, and the biological effects of promoting diabetic wound healing were markedly increased in vitro and in vivo.

Extracellular Vesicles as Biomarkers in Liver Disease

Extracellular vesicles (EVs) are membrane-derived vesicles released by a variety of cell types, including hepatocytes, hepatic stellate cells, and immune cells in normal and pathological conditions. Depending on their biogenesis, there is a complex repertoire of EVs that differ in size and origin. EVs can carry lipids, proteins, coding and non-coding RNAs, and mitochondrial DNA causing alterations to the recipient cells, functioning as intercellular mediators of cell-cell communication (auto-, para-, juxta-, or even endocrine). Nevertheless, many questions remain unanswered in relation to the function of EVs under physiological and pathological conditions. The development and optimization of methods for EV isolation are crucial for characterizing their biological functions, as well as their potential as a treatment option in the clinic. In this manuscript, we will comprehensively review the results from different studies that investigated the role of hepatic EVs during liver diseases, including non-alcoholic fatty liver disease, non-alcoholic steatohepatitis, alcoholic liver disease, fibrosis, and hepatocellular carcinoma. In general, the identification of patients with early-stage liver disease leads to better therapeutic interventions and optimal management. Although more light needs to be shed on the mechanisms of EVs, their use for early diagnosis, follow-up, and prognosis has come into the focus of research as a high-potential source of 'liquid biopsies', since they can be found in almost all biological fluids. The use of EVs as new targets or nanovectors in drug delivery systems for liver disease therapy is also summarized.

Three-Dimensional Bio-Printed Cardiac Patch for Sustained Delivery of Extracellular Vesicles from the Interface

Cardiac tissue engineering has emerged as a promising strategy to treat infarcted cardiac tissues by replacing the injured region with an ex vivo fabricated functional cardiac patch. Nevertheless, integration of the transplanted patch with the host tissue is still a burden, limiting its clinical application. Here, a bi-functional, 3D bio-printed cardiac patch (CP) design is proposed, composed of a cell-laden compartment at its core and an extracellular vesicle (EV)-laden compartment at its shell for better integration of the CP with the host tissue. Alginate-based bioink solutions were developed for each compartment and characterized rheologically, examined for printability and their effect on residing cells or EVs. The resulting 3D bio-printed CP was examined for its mechanical stiffness, showing an elastic modulus between 4-5 kPa at day 1 post-printing, suitable for transplantation. Affinity binding of EVs to alginate sulfate (AlgS) was validated, exhibiting dissociation constant values similar to those of EVs with heparin. The incorporation of AlgS-EVs complexes within the shell bioink sustained EV release from the CP, with 88% cumulative release compared with 92% without AlgS by day 4. AlgS also prolonged the release profile by an additional 2 days, lasting 11 days overall. This CP design comprises great potential at promoting more efficient patch assimilation with the host.

The Role of Extracellular Vesicles in Liver Pathogenesis

Extracellular vesicles (EVs) are generated by cells in the form of exosomes, microvesicles, and apoptotic bodies. They can be taken up by neighboring cells, and their contents can have functional impact on the cells that engulf them. As the mediators of intercellular communication, EVs can play important roles in both physiological and pathologic contexts. In addition, early detection of EVs in different body fluids may offer a sensitive diagnostic tool for certain diseases, such as cancer. Furthermore, targeting specific EVs may also become a promising therapeutic approach. This review summarizes the latest findings of EVs in the field of liver research, with a focus on the different contents of the EVs and their impact on liver function and on the development of inflammation, fibrosis, and tumor in the liver. The goal of this review is to provide a succinct account of the various molecules that can mediate the function of EVs so the readers may apply this knowledge to their own research.