Exosomal miR-500 Derived From Lipopolysaccharide-Treated Macrophage Accelerates Liver Fibrosis by Suppressing MFN2

Liver macrophage-derived exosomal miRNA-342-3p promotes liver fibrosis by inhibiting HPCAL1 in stellate cells

BACKGROUND

The progression of liver fibrosis involves complex interactions between hepatic stellate cells (HSCs) and multiple immune cells in the liver, including macrophages. However, the mechanism of exosomes in the crosstalk between liver macrophages and HSCs remains unclear.

METHOD

Exosomes were extracted from primary mouse macrophages and cultured with HSCs, and the differential expression of microRNAs was evaluated using high-throughput sequencing technology. The functions of miR-342-3p in exosomes were verified by qPCR and luciferase reporter gene experiments with HSCs. The function of the target gene Hippocalcin-like protein 1 (HPCAL1) in HSCs was verified by Western blotting, qPCR, cellular immunofluorescence and co-IP in vivo and in vitro.

RESULTS

We demonstrated that exosomal microRNA-342-3p derived from primary liver macrophages could activate HSCs by inhibiting the expression of HPCAL1 in HSCs. HPCAL1, which is a fibrogenesis suppressor, could inhibit TGF-β signaling in HSCs by regulating the ubiquitination of Smad2 through direct interactions with its EF-hand 4 domain.

CONCLUSION

This study reveals a previously unidentified profibrotic mechanism of crosstalk between macrophages and HSCs in the liver and suggests an attractive novel therapeutic strategy for treating fibroproliferative liver diseases.

Cutting-edge insights into liver fibrosis: advanced therapeutic strategies and future perspectives using engineered mesenchymal stem cell-derived exosomes

Liver fibrosis is still a serious health concern worldwide, and there is increasing interest in mesenchymal stem cells (MSCs) with tremendous potential for treating this disease because of their regenerative and paracrine effects. Recently, many researches have focused on using the released exosomes (EXOs) from stem cells to treat liver fibrosis rather than using parent stem cells themselves. MSC-derived EXOs (MSC-EXOs) have demonstrated favourable outcomes similar to cell treatment in terms of regenerative, immunomodulatory, anti-apoptotic, anti-oxidant, anti-necroptotic, anti-inflammatory and anti-fibrotic actions in several models of liver fibrosis. EXOs are superior to their parent cells in several terms, including lower immunogenicity and risk of tumour formation. However, maintaining the stability and efficacy of EXOs after in vivo transplantation remains a major challenge in their clinical applicability. Therefore, several strategies have been applied in EXOs engineering, such as parental cell modification or modifying EXOs directly to achieve optimum performance of EXOs in treating liver fibrosis. Herein, we discuss the underlying mechanisms of liver fibrosis with an overview of the available therapies, among them EXOs. We also summarise the recent developments in improving the effectiveness of EXOs with the advantages and limitations of these approaches in terms of the upcoming clinical applications.

Extracellular Vesicles in Viral Liver Diseases

Extracellular vesicles (EVs) are bilayer vesicles released by cells in the microenvironment of the liver including parenchymal and non-parenchymal cells. They are the third important mechanism in the communications between cells, besides the secretion of cytokines and chemokines and the direct cell-to-cell contact. The aim of this review is to discuss the important role of EVs in viral liver disease, as there is increasing evidence that the transportation of viral proteins, all types of RNA, and viral particles including complete virions is implicated in the pathogenesis of both viral cirrhosis and viral-related hepatocellular carcinoma. The biogenesis of EVs is discussed and their role in the pathogenesis of viral liver diseases is presented. Their use as diagnostic and prognostic biomarkers is also analyzed. Most importantly, the significance of possible novel treatment strategies for liver fibrosis and hepatocellular carcinoma is presented, although available data are based on experimental evidence and clinical trials have not been reported.

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.

Contribution of extracellular vesicles to steatosis-related liver disease and their therapeutic potential

Extracellular vesicles (EVs) are small particles released by many cell types in different tissues, including the liver, and transfer specific cargo molecules from originating cells to receptor cells. This process generally culminates in activation of distant cells and inflammation and progression of certain diseases. The global chronic liver disease (CLD) epidemic is estimated at 1.5 billion patients worldwide. Cirrhosis and liver cancer are the most common risk factors for CLD. However, hepatitis C and B virus infection and obesity are also highly associated with CLD. Nonetheless, the etiology of many CLD pathophysiological, cellular, and molecular events are unclear. Changes in hepatic lipid metabolism can lead to lipotoxicity events that induce EV release. Here, we aimed to present an overview of EV features, from definition to types and biogenesis, with particular focus on the molecules related to steatosis-related liver disease, diagnosis, and therapy.

Emerging role of exosomal microRNA in liver cancer in the era of precision medicine; potential and challenges

Exosomal microRNAs (miRNAs) have great potential in the fight against hepatocellular carcinoma (HCC), the fourth most common cause of cancer-related death worldwide. In this study, we explored the various applications of these small molecules while analyzing their complex roles in tumor development, metastasis, and changes in the tumor microenvironment. We also discussed the complex interactions that exist between exosomal miRNAs and other non-coding RNAs such as circular RNAs, and show how these interactions coordinate important biochemical pathways that propel the development of HCC. The possibility of targeting exosomal miRNAs for therapeutic intervention is paramount, even beyond their mechanistic significance. We also highlighted their growing potential as cutting-edge biomarkers that could lead to tailored treatment plans by enabling early identification, precise prognosis, and real-time treatment response monitoring. This thorough analysis revealed an intricate network of exosomal miRNAs lead to HCC progression. Finally, strategies for purification and isolation of exosomes and advanced biosensing techniques for detection of exosomal miRNAs are also discussed. Overall, this comprehensive review sheds light on the complex web of exosomal miRNAs in HCC, offering valuable insights for future advancements in diagnosis, prognosis, and ultimately, improved outcomes for patients battling this deadly disease.

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.

MicroRNA regulation of AMPK in nonalcoholic fatty liver disease

Obesity-associated nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease and is the leading cause of liver failure and death. The function of AMP-activated protein kinase (AMPK), a master energy sensor, is aberrantly reduced in NAFLD, but the underlying mechanisms are not fully understood. Increasing evidence indicates that aberrantly expressed microRNAs (miRs) are associated with impaired AMPK function in obesity and NAFLD. In this review, we discuss the emerging evidence that miRs have a role in reducing AMPK activity in NAFLD and nonalcoholic steatohepatitis (NASH), a severe form of NAFLD. We also discuss the underlying mechanisms of the aberrant expression of miRs that can negatively impact AMPK, as well as the therapeutic potential of targeting the miR-AMPK pathway for NAFLD/NASH.

Hepatocyte-derived exosomal miR-146a-5p inhibits hepatic stellate cell EMT process: a crosstalk between hepatocytes and hepatic stellate cells

Recently, Salidroside (Sal) has been demonstrated to suppress hepatic stellate cell (HSC) activation, a crucial event for liver fibrosis. Moreover, Sal has been reported to decrease hepatocyte injury. A growing number of reports have indicated that the crosstalk between hepatocytes and HSCs is very crucial for liver fibrosis development. Whether Sal-treated hepatocytes could inhibit HSC activation is unclear. Exosomes, as vital vehicles of intercellular communication, have been shown to transfer cargos between hepatocytes and HSCs. Herein, we aimed to investigate the roles of exosomal miRNAs from Sal-treated hepatocytes in HSC activation as well as liver fibrosis. Our results showed that Sal suppressed carbon tetrachloride (CCl4)-induced liver fibrosis in vivo. HSC activation as well as cell proliferation was repressed in HSCs co-cultured with Sal-treated hepatocytes. Interestingly, miR-146a-5p was up-regulated by Sal in CCl4-treated mice. Also, enhanced miR-146a-5p was found in hepatocytes isolated from Sal-treated CCl4 mice and hepatocyte-derived exosomes. Notably, hepatocyte exosomal miR-146a-5p contributed to HSC inactivation. Inhibiting miR-146a-5p in hepatocyte exosomes resulted in reduced E-cadherin (E-cad) and increased desmin in HSCs, indicating that miR-146a-5p caused HSC inactivation via epithelial-mesenchymal transition (EMT). miR-146a-5p inhibition-mediated HSC activation and EMT process were blocked down by loss of EIF5A2. Further studies revealed that EIF5A2 was a target of miR-146a-5p. Furthermore, exosomes with miR-146a-5p overexpression inhibited liver fibrosis in CCl4 mice. Collectively, exosomal miR-146a-5p from Sal-treated hepatocytes inhibits HSC activation and liver fibrosis, at least in part, by suppressing EIF5A2 and EMT process.

MiR-449a downregulation alleviates the progression of renal interstitial fibrosis by mediating the KLF4/MFN2 axis

BACKGROUND

Renal interstitial fibrosis (RIF) seriously threatens the health of individuals. MiRNAs regulate the progression of fibrosis. Nevertheless, the detailed function of miR-449a in RIF is largely unknown.

METHODS

In vitro and in vivo models of RIF were developed to evaluate the function of miR-449a. The relationship among miR-449a, KLF4, and MFN2 was explored using a dual-luciferase reporter assay and chromatin immunoprecipitation. Additionally, the pathological changes in the mice were detected using Masson staining. The mRNA and protein expressions were assessed using quantitative reverse transcription polymerase chain reaction and western blot, respectively.

RESULTS

TGF-β1 downregulated the expressions of KLF4 and MFN2 in TCMK-1 cells, but upregulated the level of miR-449a. The downregulation of miR-449a significantly inhibited TGF-β1-induced upregulation of fibrotic proteins in TCMK-1 cells. Meanwhile, miR-449a directly targeted KLF4. Moreover, KLF4 overexpression activated MFN2 transcription and reversed TGF-β1-induced fibrosis by positively regulating MFN2. Furthermore, the downregulation of miR-449a could obviously alleviate the symptoms of RIF in mice with unilateral ureteral obstruction.

CONCLUSION

MiR-449a downregulation attenuated the development of RIF by mediating the KLF4/MFN2 axis. Therefore, miR-449a might act as a target in treating RIF.

Hepatocyte-derived exosomes deliver H2AFJ to hepatic stellate cells and promote liver fibrosis via the MAPK/STMN1 axis activation

Hepatic stellate cells (HSCs) activate and acquire proliferative features in response to liver injury. However, mechanisms involved in the activation of fibrotic HSCs remain uncharacterized. This study aims at elaborating the mechanistic basis by which exosomal H2AFJ derived from hepatocytes might affect the activation of HSCs and liver fibrosis. Bioinformatics analysis based on transcriptomic RNA-seq data was used to screen out the downstream regulatory genes and pathways of H2AFJ. Mouse hepatocytes AML-12 cells were stimulated with CCl₄ to mimic an in vitro microenvironment of liver fibrosis, from which exosomes were isolated. Next, HSCs were co-cultured with hepatocyte-derived exosomes followed by detection of HSC migration and invasion in the presence of manipulated H2AFJ and STMN1 expression and MAPK pathway inhibitor. It was found that H2AFJ was highly expressed in hepatocyte-derived exosomes after CCl₄ stimulation. Hepatocyte-derived exosomal H2AFJ promoted HSC migration and invasion. H2AFJ upregulated c-jun-mediated STMN1 by activating the MAPK signaling pathway. Furthermore, in vivo experiments verified that silencing of H2AFJ attenuated liver fibrosis in mice, while restoration of STMN1 negated its effect. Collectively, hepatocyte-derived exosomal H2AFJ aggravated liver fibrosis by activating the MAPK/STMN1 signaling pathway. This study provides a potential therapeutic target for alleviating liver fibrosis.

Exosomes in liver fibrosis: The role of modulating hepatic stellate cells and immune cells, and prospects for clinical applications

Liver fibrosis is a global health problem caused by chronic liver injury resulting from various factors. Hepatic stellate cells (HSCs) have been found to play a major role in liver fibrosis, and pathological stimuli lead to their transdifferentiation into myofibroblasts. Complex multidirectional interactions between HSCs, immune cells, and cytokines are also critical for the progression of liver fibrosis. Despite the advances in treatments for liver fibrosis, they do not meet the current medical needs. Exosomes are extracellular vesicles of 30-150 nm in diameter and are capable of intercellular transport of molecules such as lipids, proteins and nucleic acids. As an essential mediator of intercellular communication, exosomes are involved in the physiological and pathological processes of many diseases. In liver fibrosis, exosomes are involved in the pathogenesis mainly by regulating the activation of HSCs and the interaction between HSCs and immune cells. Serum-derived exosomes are promising biomarkers of liver fibrosis. Exosomes also have promising therapeutic potential in liver fibrosis. Exosomes derived from mesenchymal stem cells and other cells exhibit anti-liver fibrosis effects. Moreover, exosomes may serve as potential therapeutic targets for liver fibrosis and hold promise in becoming drug carriers for liver fibrosis treatment.

MicroRNA: role in macrophage polarization and the pathogenesis of the liver fibrosis

Macrophages, as central components of innate immunity, feature significant heterogeneity. Numerus studies have revealed the pivotal roles of macrophages in the pathogenesis of liver fibrosis induced by various factors. Hepatic macrophages function to trigger inflammation in response to injury. They induce liver fibrosis by activating hepatic stellate cells (HSCs), and then inflammation and fibrosis are alleviated by the degradation of the extracellular matrix and release of anti-inflammatory cytokines. MicroRNAs (miRNAs), a class of small non-coding endogenous RNA molecules that regulate gene expression through translation repression or mRNA degradation, have distinct roles in modulating macrophage activation, polarization, tissue infiltration, and inflammation regression. Considering the complex etiology and pathogenesis of liver diseases, the role and mechanism of miRNAs and macrophages in liver fibrosis need to be further clarified. We first summarized the origin, phenotypes and functions of hepatic macrophages, then clarified the role of miRNAs in the polarization of macrophages. Finally, we comprehensively discussed the role of miRNAs and macrophages in the pathogenesis of liver fibrotic disease. Understanding the mechanism of hepatic macrophage heterogeneity in various types of liver fibrosis and the role of miRNAs on macrophage polarization provides a useful reference for further research on miRNA-mediated macrophage polarization in liver fibrosis, and also contributes to the development of new therapies targeting miRNA and macrophage subsets for liver fibrosis.

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.

Role of Small Extracellular Vesicles in Liver Diseases: Pathogenesis, Diagnosis, and Treatment

Extracellular vesicles (EVs) are vesicular bodies that bud off from the cell membrane or are secreted virtually by all cell types. Small EVs (sEVs or exosomes) are key mediators of cell-cell communication by delivering their cargo, including proteins, lipids, or RNAs, to the recipient cells where they induce changes in signaling pathways and phenotypic properties. Tangible findings have revealed the pivotal involvement of sEVs in the pathogenesis of various diseases. On the bright side, they are rich sources of biomarkers for diagnosis, prognosis, treatment response, and disease monitoring. sEVs have high stability, biocompatibility, targetability, low toxicity, and are immunogenic in nature. Their intrinsic properties make sEVs an ideal delivery vehicle to be loaded with cargo for therapeutic interventions. Liver diseases are a major global health problem. This review aims to focus on the roles and mechanisms of sEVs in the pathogenesis of liver diseases, liver injury, liver failure, and liver cancer. sEVs are released not only by hepatocytes but also by stromal and immune cells in the microenvironment. Early detection of liver disease determines the chance for curative treatment and high survival of patients. This review focuses on the potential of circulating sEV cargo as specific and sensitive noninvasive biomarkers for the early detection and prognosis of liver diseases. In addition, the therapeutic use of sEVs derived from various cell types is discussed. Although sEVs hold promise for clinical applications, there are still challenges to be overcome by further research to bring utilization of sEVs into clinical practice.

Nucleic acids and proteins carried by exosomes from various sources: Potential role in liver diseases

Exosomes are extracellular membrane-encapsulated vesicles that are released into the extracellular space or biological fluids by many cell types through exocytosis. As a newly identified form of intercellular signal communication, exosomes mediate various pathological and physiological processes by exchanging various active substances between cells. The incidence and mortality of liver diseases is increasing worldwide. Therefore, we reviewed recent studies evaluating the role of exosomes from various sources in the diagnosis and treatment of liver diseases.

Jianpi Huayu decoction inhibits the epithelial-mesenchymal transition of hepatocellular carcinoma cells by suppressing exosomal miR-23a-3p/Smad signaling

ETHNOPHARMACOLOGICAL RELEVANCE

Jianpi Huayu decoction (JHD) is a traditional Chinese medicinal preparation used to treat a variety of malignant tumors including HCC, although the underlying mechanism remains unknown. Exosomes in the tumor microenvironment mediate intercellular signaling among cancer cells, but precise contributions to hepatocellular carcinoma (HCC) progression are still elusive.

AIM OF THE STUDY

In this work, the main objective was to examine the mechanisms underlying anti-tumor effects of JHD and the potential contributions of exosomal signaling.

MATERIALS AND METHODS

LC-MS/MS was used for quality control of JDH preparation, while nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM) and western blotting were used for verification of exosomes. In vitro assays included CCK8, wound healing assay, transwell invasion assay, qRT-PCR and western blotting were performed to investigate the effects of JHD on HCC cells and the molecular mechanism. Furthermore, the effects of JHD on subcutaneous tumor model of nude mice were also determined.

RESULTS

JHD inhibited the proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) of cultured HCC cells. Further, exosomes isolated from EMT-induced HCC cells promoted the migration, invasion and EMT of other cultured HCC cells, while exosomes isolated from EMT-induced HCC cells after JHD treatment had little effect. In addition, JHD reduced the expression of exosomal miR-23a-3p in cultured HCC cells. miR-23a-3p was significantly up-regulated in tumor compared with that in adjacent non-cancerous tissues of patients with HCC. HCC patients with high miR-23a-3p expression had poor overall survival after hepatectomy. Meanwhile, miR-23a-3p enhanced HCC cell proliferation, EMT, and expression of Smad signaling proteins. More importantly, overexpression of miR-23a-3p can reverse the inhibition of EMT and Smad signaling pathway caused by JHD treatment. In vivo assays, treatment with JHD also reduced the growth of HCC-derived tumors in nude mice, reduced the expression of miR-23a-3p in serum exosomes and the level of EMT in tumor cells.

CONCLUSIONS

the antitumor effects of JHD on HCC are mediated at least in part by inhibition of EMT due to downregulation of exosome-mediated intercellular miR-23a-3p transfer and subsequent blockade of Smad signaling. Disrupting this exosomal miR-23a-3p/Smad signaling pathway may be an effective treatment.

M2 macrophage-derived exosomal microRNA-411-5p impedes the activation of hepatic stellate cells by targeting CAMSAP1 in NASH model

Liver fibrosis is a severe stage of nonalcoholic fatty liver disease (NAFLD), which is closely associated with the activation of hepatic stellate cells (HSCs) and their interaction with macrophages. Exosomes can mediate crosstalk between macrophages and HSCs in NAFLD-associated fibrosis. We found that M2 macrophage-derived exosomes significantly inhibit HSCs activation. RNA-seq studies revealed that miRNA-411-5p was decreased in serum exosomes of nonalcoholic steatohepatitis (NASH) patients as compared with that in healthy controls. Besides, miR-411-5p and M2 macrophage markers are decreased in the liver of the NASH model. We further proved that exosomal miR-411-5p from M2 macrophages inhibit HSCs activation and miR-411-5p directly downregulated the expression of Calmodulin-Regulated Spectrin-Associated Protein 1 (CAMSAP1) to inactivate stellate cells. Importantly, knockdown of CAMSAP1 also inhibited HSCs activation. This study contributes to understanding the underlying mechanism of HSCs activation and indicates CAMSAP1 may serve as a potential therapeutic target for NASH.

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M2 macrophage markers are decreased in the HFHCD-induced rat model of NASH

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M2 macrophage-derived exosomes inhibit HSCs activation via miR-411-5p

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CAMSAP1 is a direct target of miR-411-5p

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Knockdown of CAMSAP1 inhibits HSCs activation