Lipid-Induced Signaling Causes Release of Inflammatory Extracellular Vesicles From Hepatocytes

Nicotinic acid increases adipose tissue dietary fatty acid trapping and reduces postprandial hepatic and cardiac fatty acid uptake in prediabetes

Increased adipose tissue (AT) dietary fatty acids (DFA) trapping limits fatty acid exposure to lean organs in the face of elevated postprandial nonesterified fatty acid (NEFA) flux from excess AT intracellular lipolysis in prediabetes. We hypothesized that pharmacological inhibition of postprandial AT intracellular lipolysis using short-acting nicotinic acid (NA) would increase AT DFA trapping and limit AT NEFA spillover to lean organs in subjects with prediabetes. Twenty subjects with impaired glucose tolerance and 19 individuals with normal glucose tolerance underwent four postprandial studies with positron emission tomography/computed tomography with radio-labeled fatty acid tracers and stable isotopic palmitate tracers. Over the 6-h postprandial period, NA increased AT DFA partitioning with reciprocal reduction in liver and in muscle. NA also robustly reduced cardiac and liver total (DFA + NEFA) postprandial fatty acid uptake. Short-acting NA administered postprandially thus enhances AT DFA trapping and markedly reduces postprandial hepatic and cardiac fatty acid uptake. (clinicaltrials.gov NCT02808182).

Innovative nanomedicine approaches for the management of nonalcoholic fatty liver disease

Nonalcoholic fatty liver disease (NAFLD) is the most prevalent liver disorder globally. The prevalence of NAFLD in the general population is estimated to be 25-30 %, making it the most common chronic liver condition in China as well as worldwide. Given the escalating disease burden and the scarcity of effective therapeutic interventions, there is a pressing unmet clinical need. Consequently, the development of novel pharmaceuticals has emerged as a pivotal research focus in recent years. Moreover, the advent of nano-delivery technology offers innovative solutions for NAFLD drug therapy. This paper presents a comprehensive examination of the pathogenesis and therapeutic targets of NAFLD. It critically reviews the latest advancements in nanomedicine research pertinent to NAFLD treatment. The review synthesizes a broad range of research findings to bridge the gap between current knowledge and emerging therapeutic strategies, and aims to inform and guide future research directions in NAFLD management.

Exosome-mediated Transfer of lncRNA in Liver Associated Diseases; Uncovered Truths

Exosomes are extracellular vesicles with a diameter ranging from 40 to 160 nm. They are produced by hepatocytes, cholangiocytes, hepatic stellate cells (HSCs), liver sinusoidal endothelial cells (LSECs) and Kupffer cells in liver tissue. The secretion of exosomes might vary in quantity and composition in reaction to multiple triggers and various stages of disease. They transport various payloads, such as proteins, DNAs, and RNAs, and enable cell interaction to regulate myriad physiological and pathological processes in liver tissue. Long non-coding RNAs (lncRNAs) are a crucial component of exosomes with an excellent capability to regulate multiple cellular activities such as differentiation, development, metabolism, proliferation, apoptosis, and activation. With the advancements in transcriptomic and genomic study methods and database management technology, the functions and mechanisms of exosomal lncRNAs in liver diseases have been well-studied. This article delves into the detailed role of exosomal lncRNAs in liver disease onset and progression, ranging from hepatocellular carcinoma (HCC) to liver fibrosis drug-induced liver damage (DILI) and steatotic liver diseases.

Formulation-optimized oncolytic viruses: Advancing systemic delivery and immune amplification

Cancer is a major global public health challenge. Traditional treatments such as surgery, radiotherapy, and chemotherapy often show limited efficacy, minimal improvements in survival rates, and high recurrence risks. With limited therapeutic options for solid tumors, tumor immunotherapy, which harness the body's immune system, has gained significant attention. Oncolytic viruses (OVs) selectively infect and destroy tumor cells, induce immunogenic cell death (ICD) and stimulate antitumor immune responses. However, current OVs therapies, which are predominantly administered via intratumoral injection, have numerous limitations, including the need for guidance, suboptimal viral spread, extracellular matrix barriers, and immune clearance. These challenges hinder repeated dosing effectiveness and restrict its clinical applicability. Although genetic engineering has improved the tumor selectivity and immune activation of OVs, significant delivery challenges remain. Recently, optimizing pharmaceutical formulations to enhance tumor targeting and viral accumulation has emerged as a key approach to improving OV therapy and expanding clinical applicability. This review highlights the critical role of pharmaceutical formulations in biologics and outlines recent advances in OVs formulations. Specifically, we discuss strategies aimed at enhancing tumor targeting, reducing adverse effects, and promoting antitumor immunity. These strategies significantly enhance OV therapeutic potential and inform novel delivery systems for clinical translation.

Extracellular Vesicle-Mediated Network in the Pathogenesis of Obesity, Diabetes, Steatotic Liver Disease, and Cardiovascular Disease

Extracellular vesicles (EVs) are lipid bilayer-enclosed particles carrying bioactive cargo, including nucleic acids, proteins, and lipids, facilitating intercellular and interorgan communication. In addition to traditional mediators such as hormones, metabolites, and cytokines, increasing evidence suggests that EVs are key modulators in various physiological and pathological processes, particularly influencing metabolic homeostasis and contributing to the progression of cardiometabolic diseases. This review provides an overview of the most recent insights into EV-mediated mechanisms involved in the pathogenesis of obesity, insulin resistance, diabetes mellitus, steatotic liver disease, atherosclerosis, and cardiovascular disease. EVs play a critical role in modulating insulin sensitivity, glucose homeostasis, systemic inflammation, and vascular health by transferring functional molecules to target cells. Understanding the EV-mediated network offers potential for identifying novel biomarkers and therapeutic targets, providing opportunities for EV-based interventions in cardiometabolic disease management. Although many challenges remain, this evolving field highlights the need for further research into EV biology and its translational applications in cardiovascular and metabolic health.

Characterization of Extracellular Vesicles Derived From Human Precision-Cut Liver Slices in Metabolic Dysfunction-Associated Steatotic Liver Disease

Extracellular vesicles (EVs) are cell-produced, membrane-surrounded vesicles that harbour the biological features of donor cells. In the current study, we are the first to isolate and characterize EVs isolated from human precision-cut liver slices (PCLS), obtained from both healthy and metabolic dysfunction-associated steatohepatitis (MASH) cirrhotic livers. PCLS derived from patients can faithfully represent disease conditions in humans. EVs were isolated from human PCLS after incubating in normal medium or modified medium that mimics the pathophysiological environment of metabolic dysfunction associated liver disease (MASLD). MASH PCLS produced higher amounts of EVs compared to healthy PCLS (p < 0.001). Mass spectrometry revealed that around 300 proteins were significantly different in EVs derived from MASH PCLS versus healthy PCLS (FDR < 0.05), irrespective of the type of medium. Significantly changed EV proteins were largely involved in signalling receptor binding function and showed potential in promoting fibrosis. In the liver, these ligand-associated receptors are highly expressed in hepatic stellate cells, and the MASH EVs functionally promoted the activation of hepatic stellate cells. Furthermore, the amounts of EpCAM and ITGA3 in EVs were positively associated with the progression of MASLD, which suggests the use of liver-derived EVs as potential biomarkers for MASLD. Characterization of EVs derived from human PCLS may assist future studies in investigating the pathogenesis and identifying liver-specific EVs as biomarkers of MASLD.

Macrophage exosomes mediate palmitic acid-induced metainflammation by transferring miR-3064-5p to target IκBα and activate NF-κB signaling

INTRODUCTION

High palmitic acid (PA) levels trigger metainflammation, facilitating the onset and progression of chronic metabolic diseases. Recently, exosomes were identified as new inflammation mediators. However, the mechanism by which macrophage exosomes mediate PA-induced inflammation remains unclear.

OBJECTIVES

To explore how PA induces metainflammation through macrophage exosomes.

METHODS

Exosomes secreted by RAW264.7 mouse macrophages stimulated with PA (ExosPA) or not (Exos) were prepared by ultracentrifugation. The differential miRNAs between ExosPA and Exos were identified by high-throughput sequencing, and their targeted mRNAs and proteins were bioinformatically analyzed and verified by qPCR and western blot. Mouse macrophages and metabolic cells (AML-12 hepatocytes, C2C12 myocytes or 3T3-L1 adipocytes) were treated with ExosPA or Exos. The verified miRNAs and its targeted molecules related to inflammation were analyzed in recipient cells. Furthers, exosomes were prepared from primary peritoneal macrophages isolated from AIN93G diet-fed (Control PM-Exos) or HPD-fed (PA PM-Exos) mice. Control or PA PM-Exos were then tail vein injected (30 μg) into mice (n = 10), once a week for 2 weeks. The verified miRNA and its targets in blood, blood exosomes, and metabolic tissues were detected. Finally, measured the levels of miRNA, inflammatory factors, and fatty acids in the blood of 20 obese/overweight individuals and 20 healthy individuals.

RESULTS

ExoPA activate NF-κB signaling and enhance inflammatory enzyme/cytokine production in macrophages and metabolic cells. ExoPA enrich miR-3064-5p and target to inhibit IκBα as verified by exosome inhibitors and miR-3064-5p mimics and inhibitors. HPD elevates exosomal miR-3064-5p, macrophage exosomal miR-3064-5p, and inflammatory cytokine levels in mice circulation. PA PM-Exos from HPD-fed mice triggered inflammation in the circulation and metabolic tissues/organs of chow diet-fed mice. Overweight/obese individuals exhibit increased levels of circulating palmitoleic acid, exosomal miR-3064-5p, and high-sensitivity C-reactive proteins.

CONCLUSIONS

Macrophage exosomes transferring miR-3064-5p to target IκBα and activate NF-κB signaling in metabolic cells is a mechanism of PA-induced metainflammation.

Pathophysiological underpinnings of metabolic dysfunction-associated steatotic liver disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) is emerging as the leading cause of chronic liver disease worldwide, reflecting the global epidemics of obesity, metabolic syndrome, and type 2 diabetes. Beyond its strong association with excess adiposity, MASLD encompasses a heterogeneous population that includes individuals with normal body weight ("lean MASLD") highlighting the complexity of its pathogenesis. This disease results from a complex interplay between genetic susceptibility, epigenetic modifications, and environmental factors, which converge to disrupt metabolic homeostasis. Adipose tissue dysfunction and insulin resistance trigger an overflow of lipids to the liver, leading to mitochondrial dysfunction, oxidative stress, and hepatocellular injury. These processes promote hepatic inflammation and fibrogenesis, driven by cross talk among hepatocytes, immune cells, and hepatic stellate cells, with key contributions from gut-liver axis perturbations. Recent advances have unraveled pivotal molecular pathways, such as transforming growth factor-β signaling, Notch-induced osteopontin, and sphingosine kinase 1-mediated responses, that orchestrate fibrogenic activation. Understanding these interconnected mechanisms is crucial for developing targeted therapies. This review integrates current knowledge on the pathophysiology of MASLD, emphasizing emerging concepts such as lean metabolic dysfunction-associated steatohepatitis (MASH), epigenetic alterations, hepatic extracellular vesicles, and the relevance of extrahepatic signals. It also discusses novel therapeutic strategies under investigation, aiming to provide a comprehensive and structured overview of the evolving MASLD landscape for both basic scientists and clinicians.

TRIB3 Is a Hub Gene in Steatohepatitis and Aggravates Lipid Deposition and Inflammation in Hepatocytes

Background

Non-alcoholic fatty liver disease (NAFLD), also known as Metabolic dysfunction-associated fatty liver disease (MASLD), has become one of the most common chronic liver diseases worldwide, approximately 30% of adults and 70%~80% of patients with obesity and diabetes suffer from NAFLD.

Objective

We attempted to find a potential hub gene in NAFLD hepatocyte cell model induced by palmitic acid and oil acid (PAOA), and investigated the function of the hub-gene.

Methods

We searched and downloaded the GSE122660 dataset from GEO-DataSets, and differentially expressed genes (DEGs) were analyzed using R software. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed to identify the significantly activated signaling pathways in steatohepatitis. A protein-protein interaction (PPI) network was constructed to identify hub genes among the DEGs. qRT-PCR, Western blotting, and Oil Red O staining were used to explore the function of hub genes in PAOA-induced hepatocytes in vitro.

Results

A total of 255 DEGs were identified in the GSE122660 dataset and were primarily associated with inflammation-and lipid metabolism-related pathways. The tribbles pseudokinase 3 (TRIB3) was highlighted as a hub gene. We found that TRIB3 was upregulated in CDHFDinduced NAFLD mouse liver tissue and hepatocyte cell models. Furthermore, TRIB3 aggravated PAOA-induced lipid accumulation and inflammation in hepatocytes in vitro.

Conclusion

The present study identified TRIB3 as a hub gene for steatohepatitis and aggravated lipid accumulation and inflammation in vitro. Therefore, targeting TRIB3 could be a potential pharmacological strategy for NAFLD treatment.

Metabolic Dysfunction-Associated Steatohepatitis Adipose Tissue Macrophages Secrete Extracellular Vesicles That Activate Liver Fibrosis in Obese Male Mice

BACKGROUND & AIMS

Given the need for effective interventions in metabolic dysfunction-associated steatohepatitis (MASH), understanding the role of adipose tissue macrophage (ATM)-derived small extracellular vesicles (sEVs) is important. We aimed to evaluate the contribution of MASH-ATM-sEVs to the development of liver fibrosis in obese male mice.

METHODS

Using flow cytometry and nanoparticle tracking analysis, we characterized MASH-ATMs and their secreted sEVs. We assessed the fibrogenic effects of sEVs from MASH-ATMs or anti-inflammatory macrophages on stellate cells in vitro and in mice in vivo. In addition, we isolated Dicer knockdown microRNA (miRNA)-depleted sEVs from MASH-ATMs and cotreated stellate cells with MASH-ATM-sEVs and miR-155 or miR-34a antagomirs.

RESULTS

MASH-ATMs exhibited a pro-inflammatory and lipid-associated phenotype, secreting sEVs enriched in the fibrogenic miRNAs, miR-155 and miR-34a, which also down-regulate Pparg. In vitro, MASH-ATM-sEVs induced hepatic stellate cell activation and fibrogenesis and exacerbated liver fibrosis when administered to obese mice. In addition, anti-inflammatory macrophage sEVs mitigated fibrosis both in vitro and in vivo. miRNA-free Dicer knockdown-MASH-ATM-sEVs were without effects and cotreatment with miR-155/miR-34a antagomirs blocked the effects of MASH-ATM-sEVs to induce hepatic stellate cell activation.

CONCLUSIONS

This study demonstrated the role of MASH-ATM-sEVs in promoting liver fibrosis in obesity. Identification of the fibrogenic miRs, miR-155, and miR-34a, within MASH-ATM-sEVs, highlights the mechanistic importance of extrahepatic signals in MASH. These findings showed the therapeutic potential of modulating macrophage phenotypes and their sEV cargo to ameliorate MASH.

LIMA1 O-GlcNAcylation Promotes Hepatic Lipid Deposition through Inducing β-catenin-Regulated FASn Expression in Metabolic Dysfunction-Associated Steatotic Liver Disease

Hepatic lipid deposition is a key factor in progressing metabolic dysfunction-associated steatotic liver disease (MASLD). This study investigates the impact of the LIM domain and actin-binding protein 1 (LIMA1) on hepatic steatotic in MASLD and explore the underlying mechanisms. Increased levels of LIMA1 is observed in both serum and serum sEV of metabolic dysfunction-associated steatohepatitis (MASH) patients compared to healthy controls, with AUROC values of 0.76 and 0.86, respectively. Furthermore, increased LIMA1 O-GlcNAcylation is observed in mouse models of MASLD, and steatotic hepatocytes. Mechanistic studies revealed that steatosis upregulated Host cell factor 1 (HCF1) and O-GlcNAc transferase (OGT) expression, leading to catalyzed O-GlcNAcylation at the T662 site of LIMA1 and subsequent inhibition of its ubiquitin-dependent degradation. O-GlcNAcylation of LIMA1 enhances hepatocyte lipid deposition by activating β-catenin/FASn-associated signaling. Additionally, compared with their AAV8-TBG-LIMA1-WT counterparts, AAV8-TBG-LIMA1ΔT662 injection exhibited decreases in systemic insulin resistance, steatosis severity, inflammation and fibrosis in HFD-fed and CDAHFD-fed LIMA1 HKO (hepatocyte-specific knockout) mice. Moreover, LTH-sEV-mediated delivery of LIMA1 promoted MASLD progression by promoting hepatic stellate cell (HSC) activation. The findings suggest that serum sEV LIMA1 may be a potential noninvasive biomarker and therapeutic target for individuals with MASH.

Lipotoxicity Induces β-cell Small Extracellular Vesicle-Mediated β-cell Dysfunction in Male Mice

Chronically elevated circulating excess free fatty acids (ie, lipotoxicity) is a pathological process implicated in several metabolic disorders, including obesity-driven type 2 diabetes (T2D). Lipotoxicity exerts detrimental effects on pancreatic islet β-cells by reducing glucose-stimulated insulin secretion (GSIS), altering β-cell transcriptional identity, and promoting apoptosis. While β-cell-derived small extracellular vesicles (sEV) have been shown to contribute to β-cell failure in T2D, their specific role in lipotoxicity-mediated β-cell failure remains to be elucidated. In this work, we demonstrate that lipotoxicity enhances the release of sEVs from β-cells, which exhibit altered proteomic and lipidomic profiles. These palmitate (PAL)-exposed extracellular vesicles (EVs) induce β-cell dysfunction in healthy mouse and human islets and trigger significant islet transcriptional changes, including the upregulation of genes associated with the TGFβ/Smad3 pathway, as noted by RNA sequencing. Importantly, pharmacological inhibition of the TGFβI/II receptor improved PAL EV-induced β-cell dysfunction, underscoring their involvement in activating the TGFβ/Smad3 pathway during this process. We have comprehensively characterized lipotoxic β-cell sEVs and implicated their role in inducing β-cell functional failure in T2D. These findings highlight potential avenues for therapeutic interventions targeting sEV-mediated pathways to preserve β-cell health in metabolic disorders.

Roles of extracellular vesicles from different origins in metabolic-associated fatty liver disease: progress and perspectives

Metabolic-Associated Fatty Liver Disease (MAFLD) is the most common chronic liver disease worldwide, associated with systemic metabolic dysregulation. It can progress from simple hepatic steatosis (MAFL) to more severe conditions like Metabolic-Associated Steatohepatitis (MASH), fibrosis, cirrhosis, and Hepatocellular Carcinoma (HCC). There is a critical lack of reliable non-invasive diagnostic methods and effective pharmaceutical treatments for MAFLD/MASH, emphasizing the need for further research. Extracellular vesicles (EVs) are nanoscale structures that play important roles in cell signaling by delivering bioactive molecules. However, there is a significant gap in literature regarding the roles of EVs from hosts, plants, and microbiota in MAFLD. This review explores the potential of EVs from various sources-host, plants, and microbiota-as biomarkers, therapeutic agents, drug carriers, and treatment targets for MAFLD. Firstly, the roles of host-derived extracellular vesicles (EVs) in MAFLD, with a focus on cell-type specific EVs and their components-proteins, miRNAs, and lipids-for disease diagnosis and monitoring were discussed. Moreover, it highlighted the therapeutic potential of mesenchymal stem cell (MSC)-derived EVs in reducing lipid accumulation and liver injury, and immune cell-derived EVs in mitigating inflammation and fibrosis. The review also discussed the use of host-derived EVs as drug carriers and therapeutic targets due to their ability to deliver bioactive molecules that impact disease mechanisms. Additionally, it summarized research on plant-derived EVs, which help reduce liver lipid accumulation, inflammation, and enhance gut barrier function in MAFLD. Also, the review explored microbial-derived EVs as novel therapeutic targets, particularly in relation to insulin resistance, liver inflammation, and dysfunction in MAFLD. Overall, by exploring the diverse roles of EVs from host, plant, and microbiota sources in MAFLD, this review offers valuable insights into their potential as non-invasive biomarkers and novel therapeutic strategies, which could pave the way for more effective diagnostic and treatment options for this increasingly prevalent liver disease. Notably, the challenges of translating EVs into clinical practice were also thoroughly discussed, aiming to provide possible directions and strategies for future research.

Macronutrient Modulation in Metabolic Dysfunction-Associated Steatotic Liver Disease-the Molecular Role of Fatty Acids compared with Sugars in Human Metabolism and Disease Progression

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a significant public health concern, with its progression to metabolic dysfunction-associated steatohepatitis (MASH) and fibrosis leading to severe outcomes including cirrhosis, hepatocellular carcinoma, and liver failure. Whereas obesity and excess energy intake are well-established contributors to the development and progression of MASLD, the distinct role of specific macronutrients is less clear. This review examines the mechanistic pathways through which dietary fatty acids and sugars contribute to the development of hepatic inflammation and fibrosis, offering a nuanced understanding of their respective roles in MASLD progression. In terms of addressing potential therapeutic options, human intervention studies that investigate whether modifying the intake of dietary fats and carbohydrates affects MASLD progression are reviewed. By integrating this evidence, this review seeks to bridge the gap in the understanding between the mechanisms of macronutrient-driven MASLD progression and the effect of altering the intake of these nutrients in the clinical setting and presents a foundation for future research into targeted dietary strategies for the treatment of the disease.

The role of extracellular vesicles in non-alcoholic steatohepatitis: Emerging mechanisms, potential therapeutics and biomarkers

Non-alcoholic steatohepatitis (NASH), an emerging global healthcare problem, has become the leading cause of liver transplantation in recent decades. No effective therapies in the clinic have been proven due to the incomplete understanding of the pathogenesis of NASH, and further studies are expected to continue to delve into the mechanisms of NASH. Extracellular vesicles (EVs), which are small lipid membrane vesicles carrying proteins, microRNAs and other molecules, have been identified to play a vital role in cell-to-cell communication and are involved in the development and progression of various diseases. In recent years, there has been increasing interest in the role of EVs in NASH. Many studies have revealed that EVs mediate important pathological processes in NASH, and the role of EVs in NASH is distinct and variable depending on their origin cells and target cells. This review outlines the emerging mechanisms of EVs in the development of NASH and the preclinical evidence related to stem cell-derived EVs as a potential therapeutic strategy for NASH. Moreover, possible strategies involving EVs as clinical diagnostic, staging and prognostic biomarkers for NASH are summarized.

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.

Deletion of sphingosine 1-phosphate receptor 1 in myeloid cells reduces hepatic inflammatory macrophages and attenuates MASH

BACKGROUND

Immune cell-driven inflammation is a key mediator of metabolic dysfunction-associated steatohepatitis (MASH) progression. We have previously demonstrated that pharmacological sphingosine 1-phosphate (S1P) receptor modulation ameliorates MASH and is associated with attenuated accumulation of intrahepatic macrophage and T-cell subsets. Although S1P receptors are expressed on several immune cell types, given the prominent role of monocyte-derived recruited macrophages in the sterile inflammation of MASH, we hypothesized that deletion of S1P receptor 1 (S1P1) on myeloid cells may ameliorate MASH by reducing the accumulation of proinflammatory monocyte-derived macrophages in the liver.

METHODS

The LyzMCre approach was used to generate myeloid cell-specific knockout mice, termed S1pr1MKO. Littermate S1pr1loxp/loxp mice were used as wild-type controls. MASH was established by feeding mice a high-fat, -fructose, and -cholesterol (FFC) diet for 24 weeks, which led to the development of steatohepatitis and MASH-defining cardiometabolic risk factors. Liver injury and inflammation were determined by histological and gene expression analyses. Intrahepatic leukocyte populations were analyzed by mass cytometry and immunohistochemistry.

RESULTS

Histological examination demonstrated a reduction in liver inflammatory infiltrates and fibrosis in high-fat, -fructose, and -cholesterol-fed S1pr1MKO compared to wild-type. There was a corresponding reduction in alanine aminotransferase, a sensitive marker for liver injury. As determined by mass cytometry, a significant decrease in recruited macrophages was noted in the livers of high-fat, -fructose, and -cholesterol-fed S1pr1MKO mice compared to wild-type. Gene ontology pathway analysis revealed significant suppression of the peroxisome proliferator-activated receptor gamma and mitogen-activated protein kinase pathways in S1pr1MKO consistent with attenuated MASH in mice.

CONCLUSIONS

Deletion of S1P1 in myeloid cells is sufficient to attenuate intrahepatic accumulation of monocyte-derived macrophages and ameliorate murine MASH.

Circulating Extracellular Vesicles in Alcoholic Liver Disease Affect Skeletal Muscle Homeostasis and Differentiation

BACKGROUND

The mechanisms underlying muscle alteration associated to alcoholic liver disease (ALD) are not fully understood and the physiopathologic mediators of the liver-muscle interplay remains elusive. We investigated the role of circulating extracellular vesicles (EVs) in ALD as potential mediators of muscle atrophy.

METHODS

We established a mouse model of sarcopenia associated to ALD, by feeding mice with an alcoholic diet for 8 weeks. We investigated the effects of hepatic and circulating EVs isolated from these mice (EtOH mice; n = 7 females) on muscle cell cultures, comparing them with EVs from mice fed with a standard diet (CD mice; n = 6 females). Additionally, we examined the impact of circulating EVs from patients with alcohol-related cirrhosis (7 males and 2 females, mean age 55.4 years) on primary human muscle cells, comparing them with EVs from age-matched healthy subjects (6 males and 3 females). We analysed the miRNA profile of the EVs to identify potential mediators of ALD-associated sarcopenia.

RESULTS

We demonstrated that circulating EVs were internalized by muscle cells and that EVs from ALD mice and cirrhotic patients caused alteration in the myogenic program. Molecular analysis revealed that serum EVs from ALD mice reduced protein synthesis in C2C12 cells, decreasing levels of p-AKT/AKT (-54.6%; p < 0.05), p-mTOR/mTOR (-54.5%; p < 0.05) and p-GSK3(Ser9)/GSK3 (-30.63%). Similarly, hepatic EVs induced defects in muscle differentiation, with reduced levels of p-AKT/AKT (-39.1%; p < 0.05), p-mTOR/mTOR (-30.1%; p < 0.05) and p-GSK3(Ser9)/GSK3 (-40%). C2C12 cells treated with either serum or hepatic EtOH-EVs exhibited upregulated expression of muscle-specific atrophy markers Atrogin-1 (+61.2% and +189.5%, respectively; p < 0.05) and MuRF1 (+260.4% and +112.5%, respectively; p < 0.05), along with an increased LC3-II/-I ratio (+131.5% and +40.2%, respectively; p < 0.05), indicating enhanced autophagy. MiRNA analysis revealed that both circulating and hepatic EVs from ALD mice showed elevated expression of miR-21, miR-155, miR-223 and miR-122 (+230% and +292%, respectively; p < 0.01) suggesting their potential role in sarcopenia. Human muscle cells exposed to EVs from cirrhotic patients exhibited reduced protein synthesis and upregulated Atrogin-1 (+113%; p < 0.05) and MuRF1 (+86.3%; p < 0.05), indicating proteasome activation. Circulating EVs of alcoholic patients showed upregulation of the same miRNAs observed in EtOH mice, including the liver-specific miR-122 (+260%; p < 0.05) suggesting, also in human liver disease, a hepatic origin of circulating EVs.

CONCLUSIONS

Our study highlights the critical role of ALD-derived circulating EVs in affecting muscle homeostasis and myogenic program, suggesting potential therapeutic targets for mitigating muscle loss in ALD.

Therapeutic Actions of Hepatocyte Extracellular Vesicles in a Murine Model of Diet-Induced Steatohepatitis with Fibrosis

INTRODUCTION

Metabolic dysfunction-associated steatohepatitis (MASH) is a leading cause of liver failure globally and is characterized by hepatic steatosis and inflammation, which may progress to fibrosis, the severity of which is highly predictive of patient demise and death. In view of the lack of treatment options for MASH, we investigated the therapeutic properties of extracellular vesicles (EVs) from normal human hepatocytes, which we have previously been shown to alleviate toxin-mediated hepatic fibrosis in mice.

METHODS

C57BI/6J mice were fed a choline-deficient amino acid-defined high (60%) fat (CDAA-HF) diet for up to 12 weeks while receiving i.p. administration of EVs purified from cultured human HepG2 hepatocytes.

RESULTS

CDAA-HF diet consumption resulted in severe hepatic steatosis, increased frequency of CD45+ lymphocytes and F4/80+ macrophages, robust production of aortic smooth muscle actin (ACTA2), and deposition of interstitial collagen, as well as altered serum levels of ALT, AST, cholesterol, triglycerides, alkaline phosphatase, unconjugated bilirubin, and total protein, thus recapitulating typical MASH phenotypes. EVs administered preventively or therapeutically resulted in the restoration of serum marker levels, reduced hepatic inflammation and attenuation of collagen deposition, ACTA2 production, and expression of fibrosis-associated genes. HepG2 EVs contained 205 miRs and, among the 30 most abundant miRs, seven (miRs-423-5p, -483-5p, -191-5p, -148a-3p, -423-3p, -92a-3p, -122-5p) are predicted to directly target fibrosis-related genes (collagens, ACTA2, MMPs, and TIMPs).

CONCLUSIONS

Hepatocyte EVs are therapeutic in a mouse model of diet-induced steatohepatitis with fibrosis. Further studies of hepatocyte EVs or their cargo components as novel therapeutics for MASH in humans are warranted, including treatment of fibrotic stages, which are associated with clinical demise and are predictive of patient death.

Inhibited peroxidase activity of peroxiredoxin 1 by palmitic acid exacerbates nonalcoholic steatohepatitis in male mice

Reactive oxygen species exacerbate nonalcoholic steatohepatitis (NASH) by oxidizing macromolecules; yet how they promote NASH remains poorly understood. Here, we show that peroxidase activity of global hepatic peroxiredoxin (PRDX) is significantly decreased in NASH, and palmitic acid (PA) binds to PRDX1 and inhibits its peroxidase activity. Using three genetic models, we demonstrate that hepatic PRDX1 protects against NASH in male mice. Mechanistically, PRDX1 suppresses STAT signaling and protects mitochondrial function by scavenging hydrogen peroxide, and mitigating the oxidation of protein tyrosine phosphatases and lipid peroxidation. We further identify rosmarinic acid (RA) as a potent agonist of PRDX1. As revealed by the complex crystal structure, RA binds to PRDX1 and stabilizes its peroxidatic cysteine. RA alleviates NASH through specifically activating PRDX1's peroxidase activity. Thus, beyond revealing the molecular mechanism underlying PA promoting oxidative stress and NASH, our study suggests that boosting PRDX1's peroxidase activity is a promising intervention for treating NASH.

Extracellular vesicle-mediated approaches for the diagnosis and therapy of MASLD: current advances and future prospective

Metabolic dysfunction-associated steatotic liver disease (MASLD) is an asymptomatic, multifaceted condition often associated with various risk factors, including fatigue, obesity, insulin resistance, metabolic syndrome, and sleep apnea. The increasing burden of MASLD underscores the critical need for early diagnosis and effective therapies. Owing to the lack of efficient therapies for MASLD, early diagnosis is crucial. Consequently, noninvasive biomarkers and imaging techniques are essential for analyzing disease risk and play a pivotal role in the global diagnostic process. The use of extracellular vesicles has emerged as promising for early diagnosis and therapy of various liver ailments. Herein, a comprehensive summary of the current diagnostic modalities for MASLD is presented, highlighting their advantages and limitations while exploring the potential of extracellular vesicles (EVs) as innovative diagnostic and therapeutic tools for MASLD. With this aim, this review emphasizes an in-depth understanding of the origin of EVs and the pathophysiological alterations of these ectosomes and exosomes in various liver diseases. This review also explores the therapeutic potential of EVs as key components in the future management of liver disease. The dual role of EVs as biomarkers and their therapeutic utility in MASLD essentially highlights their clinical integration to improve MASLD diagnosis and treatment. While EV-based therapies are still in their early stages of development and require substantial research to increase their therapeutic value before they can be used clinically, the diagnostic application of EVs has been extensively explored. Moving forward, developing diagnostic devices leveraging EVs will be crucial in advancing MASLD diagnosis. Thus, the literature summarized provides suitable grounds for clinicians and researchers to explore EVs for devising diagnostic and treatment strategies for MASLD.

Natural History of Metabolic Dysfunction-Associated Steatotic Liver Disease: From Metabolic Syndrome to Hepatocellular Carcinoma

Introduction: Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD) stems from disrupted lipid metabolism in the liver, often linked to obesity, type 2 diabetes, and dyslipidemia. In Mexico, where obesity affects 36.9% of adults, MASLD prevalence has risen, especially with metabolic syndrome affecting 56.31% by 2018. MASLD can progress to Metabolic Dysfunction-Associated Steatohepatitis (MASH), affecting 5.27% globally, leading to severe complications like cirrhosis and hepatocellular carcinoma. Background: Visceral fat distribution varies by gender, impacting MASLD development due to hormonal influences. Insulin resistance plays a central role in MASLD pathogenesis, exacerbated by high-fat diets and specific fatty acids, leading to hepatic steatosis. Lipotoxicity from saturated fatty acids further damages hepatocytes, triggering inflammation and fibrosis progression in MASH. Diagnosing MASLD traditionally involves invasive liver biopsy, but non-invasive methods like ultrasound and transient elastography are preferred due to their safety and availability. These methods detect liver steatosis and fibrosis with reasonable accuracy, offering alternatives to biopsy despite varying sensitivity and specificity. Conclusions: MASLD as a metabolic disorder underscores its impact on public health, necessitating improved awareness and early management strategies to mitigate its progression to severe liver diseases.

HFD feeding for seven months abolishes STING disruption-driven but not female sex-based protection against hepatic steatosis and inflammation in mice

Stimulator of interferon genes (STING) is positively correlated with the degrees of liver inflammation in human metabolic dysfunction-associated steatotic liver disease (MASLD). In addition, STING disruption alleviates MASLD in mice fed a high-fat diet (HFD) for 3 months (3-m-HFD). Here we investigated the role of the duration of dietary feeding in regulating MASLD in mice and explored the involvement of STING in sex differences in MASLD. Both male and female STING-disrupted (STINGgt) and wild-type C57BL/6J mice were fed an HFD for 3 or 7 months (7-m-HFD). Additionally, female STINGgt mice upon ovariectomy (OVX) and 3-m-HFD were analyzed for MASLD. Upon 3-m-HFD, STINGgt mice exhibited decreased severity of MASLD compared to control. However, upon 7-m-HFD, STINGgt mice were comparable with wild-type mice in body weight, fat mass, and MASLD. Regarding regulating the liver RNA transcriptome, 7-m-HFD increased the expression of genes indicating proinflammatory activation of various liver cells. Interestingly, the severity of MASLD in female mice was much lighter than in male mice, regardless of STING disruption. Upon OVX, female STINGgt mice showed significantly increased severity of MASLD relative to sham control but were comparable with male STINGgt mice. Upon treatment with 17-beta estradiol (E2), hepatocytes revealed decreased fat deposition while macrophages displayed decreases in lipopolysaccharide-induced phosphorylation of Nfkb p65 and Jnk p46 independent of STING. These results suggest that 7-m-HFD, without altering female sex-based protection, abolishes STING disruption-driven protection of MASLD, likely through causing proinflammatory activation of multiple types of liver cells to offset the effect of STING disruption.

The N-terminal domain of gasdermin D induces liver fibrosis by reprogrammed lipid metabolism

BACKGROUND

The emerging incidence of pathogenic liver conditions is turning into a major concern for global health. Induction of pyroptosis in hepatocytes instigates cellular disintegration, which in turn liberates substantial quantities of pro-inflammatory intracellular substances, thereby accelerating the advancement of liver fibrosis. Consequently, directing therapeutic efforts towards inhibiting pyroptosis could potentially serve as an innovative approach in managing inflammation related chronic hepatic disorders.

METHODS

GSDMD-NTki/wt mice and Alb-creki/wt mice were generated using CRISPR/Cas9 technology. After crossing the two strains together, we induced conditional cell death by doxycycline to construct a mouse model of liver fibrosis. We analyzed differentially expressed genes by RNA sequencing and explored their biological functions. The efficacy of obeticholic acid (OCA) in the treatment of liver fibrosis was assessed.

RESULTS

Doxycycline-treated GSDMD-NTki/wt × Alb-creki/wt mice showed severe liver damage, vacuolation of hepatocytes, increased collagen fibers, and accumulation of lipid droplets. The expression of liver fibrosis related genes was greatly increased in the doxycycline-treated mouse liver compared with untreated mouse liver. RNA-sequencing showed that upregulated differentially expressed genes were involved in inflammatory responses, cell activation, and metabolic processes. Treatment with OCA alleviated the liver fibrosis, with reduced ALT and AST levels seen in the GSDMD-NTki/wt × Alb-creki/wt mice.

CONCLUSIONS

We successfully constructed a novel mouse model for liver fibrosis. This GSDMD-NT-induced fibrosis may be mediated by abnormal lipid metabolism. Our results demonstrated that we successfully constructed a mouse model of liver fibrosis, and GSDMD-NT induced fibrosis by mediating lipid metabolism.

Extracellular vesicles as a potential source of biomarkers for endocrine disruptors in MASLD: A short review on the case of DEHP

Metabolic dysfunction-Associated Steatotic Liver Disease (MASLD) is a chronic disease with increasing prevalence and for which non-invasive biomarkers are needed. Environmental endocrine disruptors (EDs) are known to be involved in the onset and progression of MASLD and assays to monitor their impact on the liver are being developed. Extracellular vesicles (EVs) mediate cell communication and their content reflects the pathophysiological state of the cells from which they are released. They can thus serve as biomarkers of the pathological state of the liver and of exposure to EDs. In this review, we present the relationships between DEHP (Di(2-ethylhexyl) phthalate) and MASLD and highlight the potential of EVs as biomarkers of DEHP exposure and the resulting progression of MASLD.

Sappanone A alleviates metabolic dysfunction-associated steatohepatitis by decreasing hepatocyte lipotoxicity via targeting Mup3 in mice

BACKGROUND AND PURPOSE

Metabolic dysfunction-associated steatohepatitis (MASH) is an inflammatory lipotoxic disorder marked by hepatic steatosis, hepatocyte damage, inflammation, and varying stages of fibrosis. Sappanone A (SA), a flavonoid, exhibits anti-inflammatory and hepatoprotection activities. Nevertheless, the effects of SA on MASH remain ambiguous. We evaluated the effects of SA on hepatocyte lipotoxicity, inflammation, and fibrosis conditions in MASH mice, as well as the underlying mechanisms.

METHODS

A conventional murine MASH model fed a methionine-choline-deficient (MCD) diet was utilized to assess the role of SA on MASH in vivo. Drug target prediction and liver transcriptomics were employed to elucidate the potential actions of SA. AML12 cells were applied to further explore the effects and mechanisms of SA in vitro.

RESULTS

The in silico prediction indicated that SA could modulate inflammation, insulin resistance, lipid metabolism, and collagen catabolic process. Treating with SA dose-dependently lessened the elevated levels of serum ALT and AST in mice with diet-triggered MASH, and high-dose SA treatment exhibited a similar effect to silymarin. Additionally, SA treatment significantly reduced lipid deposition, inflammation, and fibrosis subjected to metabolic stress in a dose-dependent manner. Besides, SA mitigated palmitate-triggered lipotoxicity in hepatocytes. Liver transcriptomics further confirmed the aforementioned findings. Of note, mRNA-sequencing analysis and molecular biology experiments demonstrated that SA statistically up-regulated the hepatic expression of major urinary protein 3 (Mup3), thereby facilitating lipid transportation and inhibiting lipotoxicity. Furthermore, Mup3 knockdown in hepatocytes significantly abolished the hepatoprotection provided by SA.

CONCLUSION

SA alleviates MASH by decreasing lipid accumulation and lipotoxicity in hepatocytes, at least partially by targeting Mup3, and subsequently blocks MASH process. Therefore, SA could be a promising hepatoprotective agent in the context of MASH.

Role of Redox Homeostasis in the Communication Between Brain and Liver Through Extracellular Vesicles

Extracellular vesicles (EVs) are small, membrane-bound particles secreted by cells into the extracellular environment, playing an increasingly recognized role in inter-organ communication and the regulation of various physiological processes. Regarding the redox homeostasis context, EVs play a pivotal role in propagating and mitigating oxidative stress signals across different organs. Cells under oxidative stress release EVs containing signaling molecules that can influence the redox status of distant cells and tissues. EVs are starting to be recognized as contributors to brain-liver communication. Therefore, in this review, we show how redox imbalance can affect the release of EVs in the brain and liver. We propose EVs as mediators of redox homeostasis in the brain-liver axis.

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.

Role and therapeutic perspectives of extracellular vesicles derived from liver and adipose tissue in metabolic dysfunction-associated steatotic liver disease

The global epidemic of metabolic diseases has led to the emergence of metabolic dysfunction-associated steatotic liver disease (MASLD) and metabolic dysfunction-associated steatohepatitis (MASH), which pose a significant threat to human health. Despite recent advances in research on the pathogenesis and treatment of MASLD/MASH, there is still a lack of more effective and targeted therapies. Extracellular vesicles (EVs) discovered in a wide range of tissues and body fluids encapsulate different activated biomolecules and mediate intercellular communication. Recent studies have shown that EVs derived from the liver and adipose tissue (AT) play vital roles in MASLD/MASH pathogenesis and therapeutics, depending on their sources and intervention types. Besides, adipose-derived stem cell (ADSC)-derived EVs appear to be more effective in mitigating MASLD/MASH. This review presents an overview of the definition, extraction strategies, and characterisation of EVs, with a particular focus on the biogenesis and release of exosomes. It also reviews the effects and potential molecular mechanisms of liver- and AT-derived EVs on MASLD/MASH, and emphasises the contribution and clinical therapeutic potential of ADSC-derived EVs. Furthermore, the future perspective of EV therapy in a clinical setting is discussed.

Investigating the Effect of Galbanic Acid on Lipin-1 and Lipin-2 Genes in Fatty Liver Cells with Palmitate

Background

Non-alcoholic fatty liver disease is related to lipid accumulation and inflammation. Considering the role of lipin-1 and lipin-2 in fat homeostasis and inflammation, this study aimed to explore the effect of galbanic acid (Gal) and resveratrol (RSV) on alterations in the gene expression levels and protein abundance of lipin-1 and lipin-2 in HepG2 liver cells lipid-enriched with palmitate (Pal).

Materials and Methods

HepG2 cells were subjected to different amounts of Gal and RSV for 24 hours in the presence of Pal to induce lipid accumulation. The RT-PCR method was employed to assess the expression of lipin-1 and lipin-2 genes, while protein levels were evaluated by western blot analysis. Lipid accumulation was determined qualitatively and semi-quantitatively using the oil-red staining technique.

Results

Gal treatment increased lipin-1 and lipin-2 gene expression (P < 0.05). In contrast, the groups treated with RSV did not show a substantial variance in the expression levels of the two genes (P > 0.05). In the groups treated with Gal/RSV, the intensity of lipin-2 protein bands was higher compared to the Pal group (P > 0.01); however, the intensity of lipin-1 protein bands was not significantly different (P > 0.05).

Conclusion

Gal, a coumarin compound, significantly increased the expression of lipin-1 and lipin-2 in HepG2 cells treated with Pal. Consequently, this research suggests gal as a novel strategy for regulating fat homeostasis in HepG2 cells.

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.

The role of hepatocyte-derived extracellular vesicles in liver and extrahepatic diseases

Extracellular vesicles (EVs) are vesicle-like bodies with a double membrane structure that are released from the cell membrane or secreted by cells into the extracellular environment. These include exosomes, microvesicles, and apoptotic bodies. There is growing evidence indicating that the composition of liver cell contents changes following injury. The quantity of EVs and the biologically active substances they carry vary depending on the condition of the liver cells. Hepatocytes utilize EVs to modulate the functions of different liver cells and transfer them to distant organs via the systemic circulation, thereby playing a crucial role in intercellular communication. This review provides a concise overview of the research on the effects and potential mechanisms of hepatocyte-derived EVs (Hep-EVs) on liver diseases and extrahepatic diseases under different physiological and pathological conditions. Common liver diseases discussed include non-alcoholic fatty liver disease (NAFLD), viral hepatitis, alcoholic liver disease, drug-induced liver damage, and liver cancer. Given that NAFLD is the most prevalent chronic liver disease globally, this review particularly highlights the use of hepatocyte-derived EVs in NAFLD for disease progression, diagnosis, and treatment.

Metabolic dysfunction-associated steatotic liver disease and extrahepatic gastrointestinal cancers

Metabolic dysfunction-associated steatotic liver disease (MASLD) poses a significant and ever-increasing health and economic burden worldwide. Substantial epidemiological evidence shows that MASLD is a multisystem disease that is associated not only with liver-related complications but is also associated with an increased risk of developing cardiometabolic comorbidities and extrahepatic cancers (principally gastrointestinal [GI] cancers). GI cancers account for a quarter of the global cancer incidence and a third of cancer-related deaths. In this narrative review, we provide an overview of the literature on (a) the epidemiological data on the risk of non-liver GI cancers in MASLD, (b) the putative mechanisms by which MASLD (and factors linked with MASLD) may increase this risk, and (c) the possible pharmacotherapies beneficially affecting both MASLD and extrahepatic GI cancer risk. There are multiple potential pathophysiological mechanisms by which MASLD may increase extrahepatic GI cancer risk. Although further studies are needed, the current evidence supports a possible extrahepatic carcinogenic role for MASLD, regardless of obesity and diabetes status, thus highlighting the potential role of tailoring cancer screening for individuals with MASLD. Although there are conflicting data in the literature, aspirin, statins and metformin appear to exert some chemo-preventive effects against GI cancer.

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.

Paraoxonase-2 agonist vutiglabridin promotes autophagy activation and mitochondrial function to alleviate non-alcoholic steatohepatitis

BACKGROUND AND PURPOSE

Only limited therapeutic agents have been developed for non-alcoholic steatohepatitis (NASH). Glabridin, a promising anti-obesity candidate, has only limited druggability due to its low in vivo chemical stability and bioavailability. Therefore, we developed vutiglabridin (VUTI), which is based on a glabridin backbone, and investigated its mechanism of action in treating NASH in animal models.

EXPERIMENTAL APPROACH

Anti-NASH effects of VUTI were determined in in vitro fatty liver models, spheroids of primary human hepatocytes and L02 normal liver cell lines. To identify VUTI possible cellular target/s, biotin-labelled VUTI was synthesized and underwent chemical proteomic analysis. Further, the evaluation of VUTI therapeutic efficacy was carried out using an amylin-NASH and high-fat (HF) diet-induced obese (DIO) mouse models. This was carried out using transcriptomic, lipidomic and proteomic analyses of the livers from the amylin-NASH mouse model.

KEY RESULTS

VUTI treatment markedly reduces hepatic steatosis, fibrosis and inflammation by promoting lipid catabolism, activating autophagy and improving mitochondrial dysfunction, all of which are hallmarks of effective NASH treatment. The cellular target of VUTI was identified as paraoxonase 2 (PON2), a newly proposed protein target for the treatment of NASH, VUTI enhanced PON2 activity. The results using PON2 knockdown cells demonstrated that PON2 is important for VUTI- activation of autophagy, promoting mitochondrial function, decreasing oxidative stress and alleviating lipid accumulation under lipotoxic condition.

CONCLUSION AND IMPLICATIONS

Our data demonstrated that VUTI is a promising therapeutic for NASH. Targeting PON2 may be important for improving liver function in various immune-metabolic diseases including NASH.

De novo synthesis of monounsaturated fatty acids modulates exosome-mediated lipid export from human granulosa cells

BACKGROUND

Ovarian somatic cells support the maturation and fertility of oocytes. Metabolic desaturation of fatty acids in these cells has a positive paracrine impact on the maturation of oocytes. We hypothesized that the enzyme stearoyl-CoA desaturase 1 (SCD1) in granulosa cells regulates the lipid cargo of exosomes secreted from these cells by maintaining the balance between saturated and unsaturated lipids. We investigated the effect of SCD1 on exosome lipid content in a cumulus-granulosa cell model under physiologically relevant in vitro conditions.

METHODS

Non-luteinized human COV434 granulosa cells were subjected to treatment with an inhibitor of SCD1 (SCDinhib) alone, in combination with oleic acid, or under control conditions. Subsequently, the exosomes were isolated and characterized via nanoparticle tracking analysis, transmission electron microscopy, and Western blotting. We used liquid chromatography mass spectrometry to investigate the lipidomic profiles. We used quantitative PCR with TaqMan primers to assess the expression of genes involved in lipogenesis and control of cell cycle progression.

RESULTS

A trend toward exosome production was observed with a shift toward smaller exosome sizes in cells treated with SCD1inhib. This trend reached statistical significance when SCDinhib was combined with oleic acid supplementation. SCD1 inhibition led to the accumulation of saturated omega-6 lipids in exosomes. The latter effect was reversed by oleic acid supplementation, which also improved exosome production and suppressed the expression of fatty acid synthase and Cyclin D2.

CONCLUSION

These findings underscore the critical role of de novo fatty acid desaturation in the regulation of the export of specific lipids through exosomes, with potential implications for controlling intercellular communication within the ovary.

A flavonoid-rich extract of bergamot juice improves high-fat diet-induced intestinal permeability and associated hepatic damage in mice

Consumption of high-fat diets (HFDs) is a contributing factor to obesity, insulin resistance and non-alcoholic fatty liver disease (NAFLD). Several studies suggested the protective role of bioactives present in Citrus fruits against the above mentioned chronic metabolic conditions. In this study, we evaluated if a flavonoid-rich extract of Citrus bergamia (bergamot) juice (BJe) could inhibit HFD-induced intestinal permeability and endotoxemia and, through this mechanism, mitigate the associated hepatic damage in C57BL/6J mice. After 12 weeks of the treatment, HFD consumption caused high body weight (BW) gain, hyperinsulinemia, hyperglycemia, and dyslipidemia, which were mitigated by BJe (50 mg per kg BW) supplementation. Furthermore, supplementation with BJe prevented HFD-induced liver alterations, including increased plasma alanine aminotransferase (ALT) activity, increased hepatic lipid deposition, high NAS, and fibrosis. Mice fed a HFD for 12 weeks showed (i) a decrease in small intestine tight junction protein levels (ZO-1, occludin, and claudin-1), (ii) increased intestinal permeability, and (iii) endotoxemia. All these adverse events were mitigated by BJe supplementation. Linking the capacity of BJe to prevent HFD-associated endotoxemia, supplementation with this extract decreased the HFD-induced overexpression of hepatic TLR-4, downstream signaling pathways (MyD88, NF-κB and MAPK), and the associated inflammation, evidenced by increased MCP-1, TNF-α, IL-6, iNOS, and F4/80 levels. Overall, we suggest that BJe could mitigate the harmful consequences of western style diet consumption on liver physiology by protecting the gastrointestinal tract from permeabilization and associated metabolic endotoxemia.

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.

Targeting cell death in NAFLD: mechanisms and targeted therapies

Nonalcoholic fatty liver disease (NAFLD) is a group of chronic liver disease which ranges from simple steatosis (NAFL) to non-alcoholic steatohepatitis (NASH) and is characterized by lipid accumulation, inflammation activation, fibrosis, and cell death. To date, a number of preclinical studies or clinical trials associated with therapies targeting fatty acid metabolism, inflammatory factors and liver fibrosis are performed to develop effective drugs for NAFLD/NASH. However, few therapies are cell death signaling-targeted even though the various cell death modes are present throughout the progression of NAFLD/NASH. Here we summarize the four types of cell death including apoptosis, necroptosis, pyroptosis, and ferroptosis in the NAFLD and the underlying molecular mechanisms by which the pathogenic factors such as free fatty acid and LPS induce cell death in the pathogenesis of NAFLD. In addition, we also review the effects of cell death-targeted therapies on NAFLD. In summary, our review provides comprehensive insight into the roles of various cell death modes in the progression of NAFLD, which we hope will open new avenues for therapeutic intervention.

Understanding Macrophage Complexity in Metabolic Dysfunction-Associated Steatotic Liver Disease: Transitioning from the M1/M2 Paradigm to Spatial Dynamics

Metabolic dysfunction-associated steatotic liver disease (MASLD) encompasses metabolic dysfunction-associated fatty liver (MASL) and metabolic dysfunction-associated steatohepatitis (MASH), with MASH posing a risk of progression to cirrhosis and hepatocellular carcinoma (HCC). The global prevalence of MASLD is estimated at approximately a quarter of the population, with significant healthcare costs and implications for liver transplantation. The pathogenesis of MASLD involves intrahepatic liver cells, extrahepatic components, and immunological aspects, particularly the involvement of macrophages. Hepatic macrophages are a crucial cellular component of the liver and play important roles in liver function, contributing significantly to tissue homeostasis and swift responses during pathophysiological conditions. Recent advancements in technology have revealed the remarkable heterogeneity and plasticity of hepatic macrophage populations and their activation states in MASLD, challenging traditional classification methods like the M1/M2 paradigm and highlighting the coexistence of harmful and beneficial macrophage phenotypes that are dynamically regulated during MASLD progression. This complexity underscores the importance of considering macrophage heterogeneity in therapeutic targeting strategies, including their distinct ontogeny and functional phenotypes. This review provides an overview of macrophage involvement in MASLD progression, combining traditional paradigms with recent insights from single-cell analysis and spatial dynamics. It also addresses unresolved questions and challenges in this area.

Exosome prospects in the diagnosis and treatment of non-alcoholic fatty liver disease

The growing prevalence of NAFLD and its global health burden have provoked considerable research on possible diagnostic and therapeutic options for NAFLD. Although various pathophysiological mechanisms and genetic factors have been identified to be associated with NAFLD, its treatment remains challenging. In recent years, exosomes have attracted widespread attention for their role in metabolic dysfunctions and their efficacy as pathological biomarkers. Exosomes have also shown tremendous potential in treating a variety of disorders. With increasing evidence supporting the significant role of exosomes in NAFLD pathogenesis, their theragnostic potential has become a point of interest in NAFLD. Expectedly, exosome-based treatment strategies have shown promise in the prevention and amelioration of NAFLD in preclinical studies. However, there are still serious challenges in preparing, standardizing, and applying exosome-based therapies as a routine clinical option that should be overcome. Due to the great potential of this novel theragnostic agent in NAFLD, further investigations on their safety, clinical efficacy, and application standardization are highly recommended.

[Regulatory effect of Diwu Yanggan Decoction on lysoglycerophospholipids in circulating exosomes in a mouse model of nonalcoholic fatty liver disease]

OBJECTIVE

To evaluate the regulatory effect of Diwu Yanggan (DWYG) Decoction on lysoglycerophospholipids (Lyso-GPLs) in circulating exosomes in a mouse model of nonalcoholic fatty liver disease (NAFLD).

METHODS

Circulating exosomes isolated from mouse serum by size exclusion chromatography were morphologically characterized using transmission electron microscope and examined for surface markers CD9, CD63 and TSG101 using Western blotting. Twenty-four male Kunming mice were randomized into 3 groups for normal feeding (control, n=8) or high-fat diet feeding for 1 week to induce NAFLD, after which the latter mice were given DWYG decoction (treatment group, n=8) or normal saline (model group, n=8) by gavage for 4 weeks. After the last treatment, blood samples were collected from the mice for testing serum TC, HDL-C, LDL-C, ALT and AST levels and isolating circulating exosomes. Using multivariate statistical analysis based on targeted metabolomics strategy, the potential biomarkers for Lyso-GPLs in the exosomes were screened.

RESULTS

The isolated exosomes about 100 nm in size had a typical saucer-like structure with distinct double-layer membranes and a mean particle size of 137.5 nm and expressed the specific surface marker proteins CD9, CD63 and TSG101. The mouse models of NAFLD had significantly increased serum levels of TC, HDL-C, LDL-C and AST and lowered serum ALT level. A total of 43 Lyso-GPLs with significant reduction after DWYG Decoction treatment were identified in NAFLD mice.

CONCLUSION

DWYG Decoction can regulate Lyso-GPLs in circulating exosomes in NAFLD mice, which provides a new clue for studying the therapeutic mechanism of DWYG Decoction for liver disease.

Cellular Senescence and Extracellular Vesicles in the Pathogenesis and Treatment of Obesity-A Narrative Review

This narrative review explores the pathophysiology of obesity, cellular senescence, and exosome release. When exposed to excessive nutrients, adipocytes develop mitochondrial dysfunction and generate reactive oxygen species with DNA damage. This triggers adipocyte hypertrophy and hypoxia, inhibition of adiponectin secretion and adipogenesis, increased endoplasmic reticulum stress and maladaptive unfolded protein response, metaflammation, and polarization of macrophages. Such feed-forward cycles are not resolved by antioxidant systems, heat shock response pathways, or DNA repair mechanisms, resulting in transmissible cellular senescence via autocrine, paracrine, and endocrine signaling. Senescence can thus affect preadipocytes, mature adipocytes, tissue macrophages and lymphocytes, hepatocytes, vascular endothelium, pancreatic β cells, myocytes, hypothalamic nuclei, and renal podocytes. The senescence-associated secretory phenotype is closely related to visceral adipose tissue expansion and metaflammation; inhibition of SIRT-1, adiponectin, and autophagy; and increased release of exosomes, exosomal micro-RNAs, pro-inflammatory adipokines, and saturated free fatty acids. The resulting hypernefemia, insulin resistance, and diminished fatty acid β-oxidation lead to lipotoxicity and progressive obesity, metabolic syndrome, and physical and cognitive functional decline. Weight cycling is related to continuing immunosenescence and exposure to palmitate. Cellular senescence, exosome release, and the transmissible senescence-associated secretory phenotype contribute to obesity and metabolic syndrome. Targeted therapies have interrelated and synergistic effects on cellular senescence, obesity, and premature aging.

IFNγ-IL12 axis regulates intercellular crosstalk in metabolic dysfunction-associated steatotic liver disease

Obesity is a major cause of metabolic dysfunction-associated steatohepatitis (MASH) and is characterized by inflammation and insulin resistance. Interferon-γ (IFNγ) is a pro-inflammatory cytokine elevated in obesity and modulating macrophage functions. Here, we show that male mice with loss of IFNγ signaling in myeloid cells (Lyz-IFNγR2-/-) are protected from diet-induced insulin resistance despite fatty liver. Obesity-mediated liver inflammation is also attenuated with reduced interleukin (IL)-12, a cytokine primarily released by macrophages, and IL-12 treatment in vivo causes insulin resistance by impairing hepatic insulin signaling. Following MASH diets, Lyz-IFNγR2-/- mice are rescued from developing liver fibrosis, which is associated with reduced fibroblast growth factor (FGF) 21 levels. These results indicate critical roles for IFNγ signaling in macrophages and their release of IL-12 in modulating obesity-mediated insulin resistance and fatty liver progression to MASH. In this work, we identify the IFNγ-IL12 axis in regulating intercellular crosstalk in the liver and as potential therapeutic targets to treat MASH.

Glycolysis in hepatic stellate cells coordinates fibrogenic extracellular vesicle release spatially to amplify liver fibrosis

Liver fibrosis is characterized by the activation of perivascular hepatic stellate cells (HSCs), the release of fibrogenic nanosized extracellular vesicles (EVs), and increased HSC glycolysis. Nevertheless, how glycolysis in HSCs coordinates fibrosis amplification through tissue zone-specific pathways remains elusive. Here, we demonstrate that HSC-specific genetic inhibition of glycolysis reduced liver fibrosis. Moreover, spatial transcriptomics revealed a fibrosis-mediated up-regulation of EV-related pathways in the liver pericentral zone, which was abrogated by glycolysis genetic inhibition. Mechanistically, glycolysis in HSCs up-regulated the expression of EV-related genes such as Ras-related protein Rab-31 (RAB31) by enhancing histone 3 lysine 9 acetylation on the promoter region, which increased EV release. Functionally, these glycolysis-dependent EVs increased fibrotic gene expression in recipient HSC. Furthermore, EVs derived from glycolysis-deficient mice abrogated liver fibrosis amplification in contrast to glycolysis-competent mouse EVs. In summary, glycolysis in HSCs amplifies liver fibrosis by promoting fibrogenic EV release in the hepatic pericentral zone, which represents a potential therapeutic target.

Real-World Effectiveness of First Line Lenvatinib Therapy in Advanced Hepatocellular Carcinoma: Current Insights

Lenvatinib received its initial approval in 2018 for the treatment of advanced hepatocellular carcinoma. It has since emerged as the preferred first line agent, supported by non-inferiority data from the REFLECT trial. Notably, lenvatinib exhibits a more favorable toxicity profile and a higher response rate compared to sorafenib. Despite the approval of immunotherapy in 2020, specifically the combination of atezolizumab and bevacizumab following the IMbrave150 trial, tyrosine kinase inhibitors remain an indispensable class of agents in the landscape of hepatocellular carcinoma treatment. This comprehensive review delves into various facets of lenvatinib utilization in hepatocellular carcinoma, shedding light on real-world data, addressing challenges, and providing insights into strategies to overcome these obstacles.

Promising nanotherapeutics of stem cell extracellular vesicles in liver regeneration

Extracellular vesicles (EVs) have gainedsignificant attention due totheir crucialroles invarious biological systems. This review aims to explore the functions of EVs in both in physiological and pathological states of the liver, with a specific focus on the potential mechanisms and concrete evidence of EVs in liver regeneration processes. The review begins by emphasizing the importance of EVs in maintaining liver health and their involvement in different pathological conditions, starting from the liver's own EVs. Reviewing the role of EVs in liver diseases to reveal the impact of EVs in pathological processes (e.g., hepatitis, liver fibrosis, and cirrhosis) and elucidate their signaling functions at the molecular level. Subsequently, the work concentrates on the functions of EVs in liver regeneration, revealing their key role in repair and regeneration following liver injury by carrying growth factors, nucleic acids, and other bioactive molecules. This part not only theoretically clarifies the mechanisms of EVs in liver regeneration but also experimentally demonstrates their role in promoting liver cell proliferation, inhibiting apoptosis, regulating immune responses, and fostering angiogenesis, laying the groundwork for future clinical applications. Moreover, this work provides a comprehensive analysis of the challenges faced by existing EV-based therapies in liver regeneration and offers prospects for future research directions. It highlights that despite the tremendous potential of EVs in treating liver diseases, there are still technical challenges (e.g., EV isolation and purification, dosage control, and targeted delivery). To overcome these challenges, the review suggests improvements to current technologies and the development of new methods to realize the clinical application of EVs in treating liver diseases.

Extracellular Vesicles and Their Correlation with Inflammatory Factors in an Experimental Model of Steatotic Liver Disease Associated with Metabolic Dysfunction

Background/Aims: Extracellular vesicles (EVs) are promising as a biomarker of metabolic dysfunction associated steatotic liver disease (MASLD). The objective is to study EVs and their involvement in MASLD concerning the disease's pathogenesis and progression characteristics. Methods: Male adult Sprague Dawley rats were randomly assigned into two experimental models of MASLD: MASLD-16 and MASLD-28, animals received a choline-deficient high-fat diet (CHFD) and Control-16 and Control-28, animals received a standard diet (SD) for 16 and 28 weeks, respectively. Biological samples from these animal models were used, as well as previously registered variables. EVs from hepatic tissue were characterized using confocal microscopy. EVs were isolated through differential ultracentrifugation from serum and characterized using NanoSight. The data from the EVs were correlated with biochemical, molecular, and histopathological parameters. Results: Liver EVs were identified through the flotillin-1 protein. EVs were isolated from the serum of all groups. There was a decrease of EVs concentration in MASLD-28 in comparison with Control-28 (P < 0.001) and a significant increase in EVs concentration in Control-28 compared with Control-16 (P < 0.001). There was a strong correlation between serum EVs concentration with hepatic gene expression of interleukin (Il)6 (r2 = 0.685, P < 0.05), Il1b (r2 = 0.697, P < 0.05) and tumor necrosis factor-alpha (Tnfa; r2 = 0.636, P < 0.05) in MASLD-16. Moreover, there was a strong correlation between serum EVs size and Il10 in MASLD-28 (r2 = 0.762, P < 0.05). Conclusion: The concentration and size of EVs correlated with inflammatory markers, suggesting their involvement in the systemic circulation, cellular communication, and development and progression of MASLD, demonstrating that EVs have the potential to serve as noninvasive biomarkers for MASLD diagnosis and prognosis.

Multicolor Two-Photon Microscopy Imaging of Lipid Droplets and Liver Capsule Macrophages In Vivo

Lipid droplets (LDs) store energy and supply fatty acids and cholesterol. LDs are a hallmark of chronic nonalcoholic fatty liver disease (NAFLD). Recently, studies have focused on the role of hepatic macrophages in NAFLD. Green fluorescent protein (GFP) is used for labeling the characteristic targets in bioimaging analysis. Cx3cr1-GFP mice are widely used in studying the liver macrophages such as the NAFLD model. Here, we have developed a tool for two-photon microscopic observation to study the interactions between LDs labeled with LD2 and liver capsule macrophages labeled with GFP in vivo. LD2, a small-molecule two-photon excitation fluorescent probe for LDs, exhibits deep-red (700 nm) fluorescence upon excitation at 880 nm, high cell staining ability and photostability, and low cytotoxicity. This probe can clearly observe LDs through two-photon microscopy (TPM) and enables the simultaneous imaging of GFP+ liver capsule macrophages (LCMs) in vivo in the liver capsule of Cx3cr1-GFP mice. In the NAFLD mouse model, Cx3cr1+ LCMs and LDs increased with the progress of fatty liver disease, and spatiotemporal changes in LCMs were observed through intravital 3D TPM images. LD2 will aid in studying the interactions and immunological roles of hepatic macrophages and LDs to better understand NAFLD.