Search Results (50)

The lack of effective anti-fibrotic agents remains a significant unmet need in the treatment of intestinal fibrosis, a condition largely driven by transforming growth factor-β1 (TGF-β1)-mediated myofibroblast activation. Phosphodiesterase 4 (PDE4) inhibitors, known to increase intracellular cAMP levels, exhibit anti-inflammatory and potential anti-fibrotic properties, though their efficacy in intestinal fibrosis is poorly defined. In this study, we investigated the anti-fibrotic effects and underlying mechanisms of PDE4 inhibitors (rolipram, roflumilast, piclamilast, and mesopram) in human intestinal myofibroblasts (HIMFs) stimulated with TGF-β1. All PDE4 inhibitors significantly reduced TGF-β1-induced mRNA expression of collagen1A1 (COL1A1) and fibronectin (FN1), with mesopram additionally reducing α-smooth muscle actin (ACTA2) mRNA expression. At the protein level, however, only roflumilast significantly decreased procollagen1A1 (Procol1A1) and FN expression. Mechanistically, roflumilast, rolipram, and mesopram significantly reduced serum response factor (SRF) mRNA expression, whereas piclamilast and mesopram significantly inhibited myocardin-related transcription factor A (MRTFA) mRNA expression. Rolipram and roflumilast exhibited a decreasing trend in MRTFA mRNA expression without statistical significance. Notably, roflumilast demonstrated superior inhibitory effects, significantly decreasing both MRTF-A and SRF protein expression and effectively reducing nuclear localization of MRTF-A. Additionally, rolipram and roflumilast significantly attenuated TGF-β1-induced phosphorylation of Smad2. These findings indicate that PDE4 inhibitors, particularly roflumilast, effectively suppress TGF-β1-induced fibrogenic activation in HIMFs by modulating MRTF/SRF and Smad-dependent pathways, highlighting the value of roflumilast for further preclinical investigation as a potential therapeutic strategy for intestinal fibrosis. Full article

Background: ACTA2 encodes smooth muscle alpha-actin and is one of the most common genetic causes of inherited non-syndromic thoracic aortic aneurysm and dissection. Although murine models have provided important mechanistic insight, complementary vertebrate systems may enable more rapid in vivo phenotyping and future therapeutic screening. Methods: Utilizing a CRISPR/Cas9-based approach, we developed zebrafish acta2 mutant models and assessed phenotypes at larval and adult stages. At 3 days post-fertilization, larvae were screened by brightfield microscopy for edema, axis defects, hemorrhage, and a composite endpoint (any phenotype) under basal conditions and after exposure to 0.2 mM epinephrine. Phenotype occurrence was summarized as group-specific proportions across a 2 × 2 design defined by genotype (wild-type vs. acta2-deficient mutant) and treatment (DMSO control vs. epinephrine), with prespecified pairwise comparisons using Pearson’s chi-squared tests. Pooled fish-level logistic regression models were also fit for each endpoint. Adult follow-up was performed by genotyping all available acta2 fish at the facility and tracking staggered tank-level cohorts longitudinally. Results: Initial gross morphologic assessment did not reveal overt external phenotypic differences between heterozygous or homozygous acta2 mutant larvae and wild-type controls. In larval analyses, the mutant genotype was associated with a greater burden of adverse phenotypes than treatment exposure. For the composite endpoint, mutant larvae demonstrated higher proportions than normal larvae under both control (28.3% vs. 17.4%, p = 0.007) and epinephrine conditions (26.9% vs. 17.4%, p = 0.023), whereas epinephrine did not significantly alter composite phenotype frequency within either genotype. Similar genotype-associated trends were observed for axis defects and hemorrhage. In pooled logistic regression, acta2 deficiency was associated with increased odds of axis defects (OR 2.64, 95% CI 1.48–4.89, p = 0.001), hemorrhage (OR 2.40, 95% CI 1.09–5.68, p = 0.036), and the composite endpoint (OR 1.88, 95% CI 1.19–3.00, p = 0.008), whereas epinephrine exposure did not demonstrate a consistent independent effect across endpoints. Adult staggered follow-up showed greater attrition in homozygous mutant cohorts than in wild-type or heterozygous cohorts, with aggregated losses of 24%, 12%, and 3%, respectively. Conclusions: This preliminary zebrafish acta2 model demonstrated that acta2 deficiency is associated with increased adverse larval phenotype burden and suggested reduced long-term persistence of homozygous mutant fish in adulthood. The strongest signal in the current study was genotype-associated phenotype burden rather than a robust epinephrine-dependent effect. These findings support the feasibility of zebrafish-based ACTA2 phenotyping while highlighting the need for more specific vascular endpoints, refined longitudinal follow-up, and future variant-specific modeling. Full article

Ameloblastoma is a common benign odontogenic tumor. Its etiology has been associated with dysregulation of the MAPK and SHH pathways, and new theories suggest that tumor stem cells (TSCs) and the epithelial–mesenchymal transition (EMT) are participants in their pathogenesis. Objective: To determine the immunohistochemical expression of SOX2 and CD44 as indicators of TSCs and the gene expression of vimentin, smooth muscle actin, and FGFR1 as indicators of the EMT in conventional, unicystic, and peripheral ameloblastoma. Materials and Methods: Conventional, unicystic, and peripheral ameloblastomas and dental follicles, as a control group, were analyzed by peroxidase immunohistochemistry assays for SOX2 and CD44 as TSC-related markers, and the EMT relationship was determined by RT-qPCR expression for vimentin (VIM), alpha smooth muscle actin (ACTA2), fibroblast growth factor receptor 1 (FGFR1), and GAPDH as a control. Results: The most affected anatomical site was the mandible, with an average age of 38.03 (±20.95) years. SOX2 and CD44 immunoexpression were significantly higher in conventional ameloblastoma. RT-qPCR results showed predominant non-significant expression of VIM, ACTA2, and FGFR1 in unicystic ameloblastoma compared to other ameloblastoma types. Conclusion: The significantly higher immunoexpression of SOX2 and CD44 in conventional subtypes could suggest a greater presence of TSCs, and predominant VIM, ACTA2, and FGFR1 gene expression in unicystic ameloblastoma could suggest the possibility of EMT processes related to cystic formation. More research on TSCs and the EMT is necessary to elucidate this finding. Full article

Moyamoya angiopathy (MMA) is a rare, chronic progressive cerebrovascular condition characterized by bilateral stenosis or occlusion of the terminal internal carotid arteries and their major branches. This progressive occlusion triggers the development of telangiectatic and fragile vessels at the base of the brain, creating the characteristic angiographic appearance of a “puff of smoke.” Depending on the etiology, MMA is classified as Moyamoya Disease (MMD) when idiopathic and primary or Moyamoya Syndrome (MMS) when associated with underlying systemic conditions. While the RNF213 gene, particularly the p.R4810K variant, is recognized as the major susceptibility locus for MMD in East Asian populations, it does not fully account for the global genetic landscape or the phenotypic diversity of the disease. This review provides a comprehensive overview of the genetic architecture of the entire MMA spectrum, exploring loci beyond RNF213. We analyze the role of genes involved in vascular smooth muscle cell contractility (ACTA2, MYH11), TGF-β signaling, and DNA repair mechanisms that drive MMS, alongside the genetic basis of syndromic forms associated with neurofibromatosis type 1, trisomy 21, and RASopathies. Understanding these diverse genetic drivers is crucial for early diagnosis, risk stratification, and the development of targeted molecular therapies. Full article

Large-scale expansion of human mesenchymal stem cells (hMSCs) remains a major challenge due to the intrinsic trade-off between cell proliferation and the maintenance of multipotency in conventional culture systems. Stiff substrates, such as tissue culture polystyrene or rigid hydrogels, promote rapid proliferation but induce progressive loss of stemness, whereas very soft matrices preserve multipotency at the expense of cell growth. To overcome this limitation, we developed mechanically soft, phase-separated gelatin–phenol/hyaluronic acid–phenol (Gtn-Ph/HA-Ph) hydrogels with precisely controlled microstructures via enzyme-mediated crosslinking. These hydrogels consist of HA-rich, dot-like domains embedded within a continuous Gtn-rich network, allowing for independent tuning of stiffness and domain architecture. On single-component Gtn-Ph hydrogels, hMSC proliferation increased with substrate stiffness, whereas soft hydrogels with a storage modulus (G′) of approximately 0.6 kPa markedly suppressed proliferation while preserving stemness marker expression, confirming the stiffness-dependent trade-off. In contrast, phase-separated Gtn-Ph/HA-Ph hydrogels supported robust hMSC proliferation even under soft mechanical conditions while maintaining high expression of stemness-associated markers. During long-term culture, hMSCs achieved a 68- to 195-fold increase in cumulative cell yield on soft Gtn-Ph/HA-Ph hydrogels (G′ = 0.5 kPa) compared with tissue culture polystyrene. Expression of α-smooth muscle actin (α-SMA) mRNA, encoded by the ACTA2 gene and associated with cellular senescence and fibrotic activation, was completely suppressed, while hMSCs retained robust adipogenic, osteogenic, and chondrogenic differentiation capacities. These results demonstrate that phase-separated Gtn-Ph/HA-Ph hydrogels effectively resolve the proliferation–multipotency dilemma in hMSC expansion and provide a promising platform for scalable manufacturing of therapeutic stem cells. Full article

Idiopathic pulmonary fibrosis (IPF) is a chronic, progressive lung disease characterized by the pathological accumulation of collagen-rich extracellular matrix, resulting in irreversible lung remodeling and respiratory failure. The incomplete understanding of IPF pathogenesis has hindered the development of effective therapeutics. Here, we investigate the mechanism by which the actin-related protein 2/3 complex subunit 2 (ARPC2) contributes to the fibrotic response in lung fibroblasts. Modulating of ARPC2 expression levels altered the expression of profibrotic genes, including α-smooth muscle actin (ACTA2), in TGF-β1-treated MRC-5 cells at the transcriptional level. We further show that ARPC2 regulates the TGF-β1-mediated nuclear translocation of myocardin-related transcription factor-A (MRTFA), a central driver of fibrotic gene induction. Our data indicate that ARPC2 plays a distinct role in profibrotic gene expression and MRTFA nuclear localization, distinguishing its function from other components of the actin-related protein 2/3 (ARP2/3) complex. Furthermore, ARPC2 appears to modulate the TGF-β1-dependent formation of MRTFA/G-actin complexes. Finally, transcriptomic analysis of cells depleted of ARPC2, ACTR2, or MRTFA revealed that ARPC2 and MRTFA co-regulate a specific repertoire of fibrotic genes. These observations support a profibrotic function for ARPC2 during fibroblast-to-myofibroblast transition (FMT), highlighting it as a potential therapeutic target for IPF. Full article

Tubule-derived pro-fibrotic mediators are central for the development of kidney fibrosis. We previously showed that fibrotic stimuli activate and elevate GEF-H1 (ARHGEF2) in tubular cells, leading to RhoA-dependent fibrotic reprogramming. In search of new mechanisms of GEF-H1 regulation, here we used immunoprecipitation and proximity ligation assay to show interaction between GEF-H1 and Myotonic Dystrophy Kinase-related Cdc42-binding kinase (MRCK)α in tubular cells. MRCKα silencing elevated GEF-H1 activity, and induced GEF-H1-dependent RhoA activation, stress fibre formation and myosin light chain phosphorylation. MRCKα depletion also elevated phospho-cofilin levels in a RhoA-dependent manner. The fibrogenic cytokine TGFβ1 rapidly increased binding between GEF-H1 and MRCKα, while MRCKα silencing augmented TGFβ1-induced GEF-H1 activation, suggesting a negative feedback loop. An mRNA array detecting fibrogenic genes revealed increase in a subset of basal and TGFβ1-induced genes following MRCKα depletion. MRCKα silencing promoted nuclear translocation of the profibrotic transcriptional co-activator Myocardin-Related Transcription Factor (MRTF), and MRTF-A+B depletion prevented increase in ACTA2 (α-smooth muscle actin), a key marker of fibrotic reprogramming. Finally, total MRCKα mRNA was reduced in a murine kidney fibrosis model, and immunohistochemistry revealed a decrease in tubular MRCKα. Taken together, we identified MRCKα as a new suppressor of GEF-H1/RhoA/MRTF signaling. Reduced MRCKα expression in kidney fibrosis may promote tubular fibrotic gene expression. Full article

This study evaluated the therapeutic potential and underlying molecular mechanisms of the citrus flavonoid Hes in combination with the chemotherapeutic agent DOX in human RB cells. Cells were treated with Hes alone or in combination with DOX for 24 and 48 h. Hes significantly inhibited cell proliferation and migration and promoted apoptotic cell death, while enhancing the cytotoxic response to DOX under in vitro conditions. Molecular analyses demonstrated that combination treatment markedly modulated ECM-associated markers, including the downregulation of matrix metalloproteinases MMP-2 and MMP-9 and ACTA2 (α-smooth muscle actin, α-SMA), along with the upregulation of tissue inhibitors of metalloproteinases TIMP-1 (tissue inhibitor of metalloproteinases) and TIMP-2. In parallel, the expression of apoptosis-related genes was altered, as evidenced by the upregulation of the B-cell lymphoma 2 (Bcl-2)-associated X protein (Bax) and Caspase-3 and the downregulation of Bcl-2. Overall, these findings indicate that Hes enhances DOX efficacy by simultaneously engaging apoptotic and migration-associated molecular processes, supporting its potential role as a preclinical chemosensitizing agent that warrants further investigation in advanced experimental models. Full article

Dietary pattern characterized by low intake of vegetables and fruits and high consumption of fat, soft drink and desserts are associated with an increased risk of chronic diseases. To investigate the effects of folate status and fructose intake on adenine-induced chronic kidney disease (CKD), seven-week-old C57BL/6 mice were divided into six groups and fed either a control diet (Ctrl), a 26% (w/w) high-fructose diet (Hfru), Ctrl plus 0.15% adenine (Ctrl+ade), Hfru+ade, Hfru with folate deficiency plus adenine (Hfru−f+ade), or Hfru with tenfold folate supplementation plus adenine (Hfru+f10+ade). After 10 weeks on the assigned diets, adenine was administrated to the +ade groups for 7 weeks. The results showed that all adenine-treated mice exhibited increased fasting blood glucose, urinary glucose, and elevated renal expression of collagen 1a1 (Col1a1), fibronectin (Fn1), and smooth muscle α-actin (Acta2). Compared with Ctrl mice, Hfru-fed mice showed significantly higher serum creatinine, increased urinary protein, and reduced creatinine clearance. Adenine induced kidney injury in all +ade groups, with the most severe damage observed in Hfru−f+ade mice, as indicated by elevated blood urine nitrogen (BUN), urinary protein, neutrophil gelatinase-associated lipocalin (NGAL), and renal fibrosis. In contrast, Hfru+f10+ade mice showed the lowest levels of these renal injury markers. The Hfru+ade diets increased renal Hif1α and iNos gene expression, which was further exacerbated by folate deficiency. Secretion of the anti-inflammatory cytokine interleukin (IL-10) by splenocytes was significantly reduced under folate-deficient conditions. Renal IL-10 levels were suppressed in all +ade groups but were significantly increased by folate supplementation. Renal IL-10 levels were negatively correlated with the inflammatory chemokine monocyte chemoattractant protein (MCP-1) and transforming growth factor (TGF)-β, whereas renal MCP-1 levels showed positive correlations with TGF-β and IL-6. Overall, these findings suggest that high fructose consumption in the absence of adequate folate intake may be of concern for CKD progression. Full article

High-grade sarcomas often lack typical morphological features and exhibit no clear differentiation, often leading to a diagnosis of undifferentiated sarcoma (US). Pleomorphic leiomyosarcoma (PLMS) is a high-grade sarcoma consisting of a typical leiomyosarcoma (LMS) component alongside dedifferentiated high-grade areas. A few decades ago, PLMS was regarded as a subtype of high-grade sarcoma previously referred to as malignant fibrous histiocytoma; it is now classified as a variant of LMS. The mechanisms underlying myogenic differentiation and their relevance to the pathological diagnosis of high-grade sarcomas remain poorly understood. To investigate the gene expression networks associated with myogenic differentiation, we employed Cap Analysis of Gene Expression (CAGE) to distinguish PLMS from other high-grade sarcoma subtypes. We analyzed 27 frozen high-grade sarcoma samples, comprising 10 PLMSs, 11 high-grade myxofibrosarcomas, 3 dedifferentiated liposarcomas, 2 USs, and 1 high-grade sarcoma not otherwise specified, using CAGE profiling. Hierarchical clustering based on differentially expressed genes identified by CAGE separated 7 of the 10 PLMSs from other high-grade sarcomas, while the remaining 3 PLMSs clustered with a single US case. CAGE analysis also revealed that the myostatin (MSTN) promoter (false discovery rate [FDR] < 0.05) was more strongly activated in the high-grade sarcoma group lacking morphological and immunohistochemical smooth muscle differentiation than in the PLMS group, whereas the alpha smooth muscle actin (ACTA2) promoter (FDR < 0.05) was more prominently activated in the PLMS group. Immunohistochemical analysis showed reduced or absent myostatin expression in PLMSs, in contrast to diffuse myostatin expression in other high-grade sarcomas. Smooth muscle actin, encoded by ACTA2, was expressed in all 10 PLMS cases but only in 11 of 17 other high-grade sarcomas. Furthermore, both conventional immunohistochemistry and double immunostaining revealed that myostatin and myogenic markers exhibited largely mutually exclusive expression patterns within these tumors. A validation study was performed using 59 soft tissue sarcoma cases, including 27 PLMSs and 16 LMSs. Loss or reduction in myostatin expression was confirmed in both LMS and PLMS, and the ratio of myostatin loss was comparable (62.5% in LMS vs. 63% in PLMS). Collectively, these findings suggest that myostatin contributes to smooth muscle differentiation in high-grade sarcomas and has potential utility as a diagnostic marker. Full article

Thoracic aortic aneurysms are life-threatening vascular conditions linked to inherited disorders such as Marfan syndrome, Loeys–Dietz syndrome, vascular Ehlers–Danlos syndrome, and familial thoracic aortic aneurysms and dissections. While traditionally associated with the extracellular matrix and contractile defects in vascular smooth muscle cells, emerging evidence suggests the key role of mitochondrial dysfunction. Here, we show that the overexpression of ACTA2^R179H and TGFBR2^G357W in murine aortic VSMCs reduces Mitochondrial Transcription Factor A (Tfam) expression, decreases mitochondrial DNA (mtDNA) content, and impairs oxidative phosphorylation, shifting metabolism toward glycolysis. Notably, nicotinamide riboside, a NAD⁺ precursor, restores mitochondrial respiration, increases Tfam and mtDNA levels, and promotes a contractile phenotype by enhancing actin polymerization and reducing matrix metalloproteinase activity. These findings identify mitochondrial dysfunction as a shared feature in hereditary thoracic aortic aneurysm, not only in Marfan syndrome, but also in other genetic forms, and highlight mitochondrial boosters as a potential therapeutic strategy. Full article

Thoracic aortic aneurysms (TAAs) pose a significant health burden due to their asymptomatic progression, often culminating in life-threatening aortic rupture, and due to the lack of effective pharmacological treatments. Risk factors include elevated hemodynamic stress on the ascending aorta, frequently associated with hypertension and hereditary genetic mutations. Among the hereditary causes, Marfan syndrome is the most prevalent, characterized as a connective tissue disorder driven by FBN1 mutations that lead to life-threatening thoracic aortic ruptures. Similarly, mutations affecting the TGF-β pathway underlie Loeys–Dietz syndrome, while mutations in genes encoding extracellular or contractile apparatus proteins, such as ACTA2, are linked to non-syndromic familial TAA. Despite differences in genetic origin, these hereditary conditions share central pathophysiological features, including aortic medial degeneration, smooth muscle cell dysfunction, and extracellular remodeling, which collectively weaken the aortic wall. Recent evidence highlights mitochondrial dysfunction as a crucial contributor to aneurysm formation in Marfan syndrome. Disruption of the extracellular matrix–mitochondrial homeostasis axis exacerbates aortic wall remodeling, further promoting aneurysm development. Beyond its structural role in maintaining vascular integrity, the ECM plays a pivotal role in supporting mitochondrial function. This intricate relationship between extracellular matrix integrity and mitochondrial homeostasis reveals a novel dimension of TAA pathophysiology, extending beyond established paradigms of extracellular matrix remodeling and smooth muscle cell dysfunction. This review summarizes mitochondrial dysfunction as a potential unifying mechanism in hereditary TAA and explores how understanding mitochondrial dysfunction, in conjunction with established mechanisms of TAA pathogenesis, opens new avenues for developing targeted treatments to address these life-threatening conditions. Mitochondrial boosters could represent a new clinical opportunity for patients with hereditary TAA. Full article

Background: Fibroblast activation protein (FAP) is a cell surface glycoprotein expressed by myofibroblastic cells in areas of active tissue remodeling, such as wound healing, fibrosis, and certain chronic inflammatory lesions. As FAP is uniquely present in chronic inflammatory lesions and has an important role in extracellular matrix (ECM) turnover, it appears to have all the characteristics necessary for involvement in atherosclerosis and atherosclerotic plaque rupture and has become a potential target in the treatment of myocardial infarction. Methods: To further understand the role of FAP, its expression in atherosclerotic plaques was examined in a genetically modified mouse model of accelerated atherosclerosis (Apobec1 −/− Ldlr −/− double-knockout mice). The immunohistochemical Fap staining of atherosclerotic plaques in a mouse model of atherosclerosis was correlated with quantification of Fap mRNA obtained from the atherosclerotic plaques of the aortic arch. Fap distribution was characterized in mouse atherosclerotic plaques relative to other markers of activated smooth muscle cells, such as alpha smooth muscle actin and myosin heavy chain (Acta2 and Myh2), ECM turnover (Ki-67, procollagen III and Mmp-9), and inflammation in atherosclerosis (Cd-44, Il-12 and Tgf beta) using immunohistochemistry (IH) and RT-PCR analysis. Results: The mouse model of accelerated atherosclerosis showed an increasing presence of Fap with the progression of atherosclerosis and a high expression level in advanced atherosclerotic lesions compared with other markers of ECM turnover and inflammation in atherosclerosis. Conclusions: FAP exhibits a distinct pattern of expression in a mouse model of atherosclerosis as compared to other markers of activated vascular smooth muscle cells, ECM degeneration, and inflammatory cytokines. Full article

Telocytes (TCs) are distinctive cells widely localized in the stromal compartment of several human organs, including the skin. By means of their peculiar prolongations named telopodes, skin TCs are organized in networks interconnected with a variety of adjacent cells, being thus supposed to take part in skin homeostasis through both cell-to-cell contacts and the release of extracellular vesicles. A disarrangement/loss of the TC network was shown in human fibrotic skin as well as in the murine model of bleomycin-induced cutaneous fibrosis, but whether such TC alterations may represent just a consequence or a trigger of the fibrotic process still remains to be clarified. Thus, we investigated the effects of skin TC secretome as conditioned medium (TC-CM) on the transition of skin fibroblasts into myofibroblasts promoted by the master profibrotic cytokine transforming growth factor β1 (TGFβ1). Primary cultures of both adult human skin TCs and fibroblasts were obtained by means of immunomagnetic cell separation. Nanoparticle tracking analysis was carried out to measure extracellular vesicles in TC-CM. The combination of multiple morphological, gene/protein expression, and functional assessments demonstrated that TC-CM was able to significantly prevent TGFβ1-induced fibroblast-to-myofibroblast transition. TC-CM did not influence cell viability, while it effectively inhibited TGFβ1-induced fibroblast proliferation, migration, and morphological changes. Indeed, TC-CM was able to reduce TGFβ1-mediated skin fibroblast phenotypic and functional differentiation into myofibroblasts, as shown by a significant decrease in FAP, ACTA2, COL1A1, COL1A2, FN1, and CTGF gene expression, α-smooth muscle actin, N-cadherin, COL1A1, and FN-EDA protein levels, and collagen gel matrix contraction. Furthermore, TC-CM significantly lowered TGFβ1-mediated ERK1/2 signaling pathway activation. This in vitro study proves for the first time that TCs may play an important role in skin homeostasis through the prevention of fibroblast-to-myofibroblast transition via paracrine mechanisms and affords the necessary basis to investigate in the future the feasibility of TC secretome as an innovative antifibrotic therapeutic tool. Full article

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. Full article