A high-fat diet and multiple administration of carbon tetrachloride induces liver injury and pathological features associated with non-alcoholic steatohepatitis in mice

Different bacteria species lipopolysaccharide co-exposure with NASH diet exacerbate NASH and liver fibrosis progress in mice

BACKGROUND AND AIM

Given the obesity epidemic, nonalcoholic fatty liver disease has become a public health concern; however, the progression mechanism remains obscure. Therefore, experimental nonalcoholic fatty liver disease/steatohepatitis (NASH) animal models that reflect human disease are necessary. In this study, we simulated the effects of gut microbiota imbalance on NASH and liver fibrosis.

METHODS

Different bacterial sources of lipopolysaccharide, including Escherichia coli (GEC) and Salmonella abortus equi (GSE), were combined with a Gubra Amylin NASH (GAN) diet to induce NASH and liver fibrosis.

RESULTS

Serum levels of alanine aminotransferase, hydroxyproline, CD68-positive cells, α-smooth muscle actin, and glial fibrillary acidic protein as well as TNF-α, COL1A1, TGF-β, and NLRP3 expressions in the livers of the GSE group were markedly increased compared to those in the GAN group. The GAN diet with lipopolysaccharide (LPS) treatment resulted in a marked difference in microbiota α-diversity. The GSE group had higher numbers ofincreased Erysipelotrichaceae, Akkermansiaceae, and Bacteroidaceae families than the other groups.

CONCLUSIONS

Based on these results, the GAN diet combined with LPS treatment successfully induced the progression of liver disease to NASH and fibrosis. With consistent histologically proven fibrosis, this obese NASH mouse model has relatively good clinical translatability and is highly applicable for preclinical drug testing for NASH.

Progress in the Study of Animal Models of Metabolic Dysfunction-Associated Steatotic Liver Disease

Metabolic dysfunction-associated steatotic liver disease (MASLD) has recently been proposed as an alternative term to NAFLD. MASLD is a globally recognized chronic liver disease that poses significant health concerns and is frequently associated with obesity, insulin resistance, and hyperlipidemia. To better understand its pathogenesis and to develop effective treatments, it is essential to establish suitable animal models. Therefore, attempts have been made to establish modelling approaches that are highly similar to human diet, physiology, and pathology to better replicate disease progression. Here, we reviewed the pathogenesis of MASLD disease and summarised the used animal models of MASLD in the last 7 years through the PubMed database. In addition, we have summarised the commonly used animal models of MASLD and describe the advantages and disadvantages of various models of MASLD induction, including genetic models, diet, and chemically induced models, to provide directions for research on the pathogenesis and treatment of MASLD.

Machine learning model for non-alcoholic steatohepatitis diagnosis based on ultrasound radiomics

BACKGROUND

Non-Alcoholic Steatohepatitis (NASH) is a crucial stage in the progression of Non-Alcoholic Fatty Liver Disease(NAFLD). The purpose of this study is to explore the clinical value of ultrasound features and radiological analysis in predicting the diagnosis of Non-Alcoholic Steatohepatitis.

METHOD

An SD rat model of hepatic steatosis was established through a high-fat diet and subcutaneous injection of CCl4. Liver ultrasound images and elastography were acquired, along with serum data and histopathological results of rat livers.The Pyradiomics software was used to extract radiomic features from 2D ultrasound images of rat livers. The rats were then randomly divided into a training set and a validation set, and feature selection was performed through dimensionality reduction. Various machine learning (ML) algorithms were employed to build clinical diagnostic models, radiomic models, and combined diagnostic models. The efficiency of each diagnostic model for diagnosing NASH was evaluated using Receiver Operating Characteristic (ROC) curves, Clinical Decision Curve Analysis (DCA), and calibration curves.

RESULTS

In the machine learning radiomic model for predicting the diagnosis of NASH, the Area Under the Curve (AUC) of ROC curve for the clinical radiomic model in the training set and validation set were 0.989 and 0.885, respectively. The Decision Curve Analysis revealed that the clinical radiomic model had the highest net benefit within the probability threshold range of > 65%. The calibration curve in the validation set demonstrated that the clinical combined radiomic model is the optimal method for diagnosing Non-Alcoholic Steatohepatitis.

CONCLUSION

The combined diagnostic model constructed using machine learning algorithms based on ultrasound image radiomics has a high clinical predictive performance in diagnosing Non-Alcoholic Steatohepatitis.

Identification of Two Long Noncoding RNAs, Kcnq1ot1 and Rmst, as Biomarkers in Chronic Liver Diseases in Mice

This study investigates novel short-lived long noncoding RNAs (lncRNAs) in mice with altered expression in metabolic dysfunction-associated steatotic liver (MASH) and liver fibrosis. LncRNAs share similarities with mRNAs in their transcription by RNA polymerase II, possession of a 5' cap structure, and presence of a polyA tail. We identified two lncRNAs, Kcnq1ot1 and Rmst, significantly decreased in both conditions. These lncRNAs showed dramatic expression changes in MASH livers induced by Western diets and CCl4, and in fibrotic livers induced by CCl4 alone. The decrease was more pronounced in liver fibrosis, suggesting their potential as biomarkers for disease progression. Our findings are consistent across different fibrosis models, indicating a crucial role for these lncRNAs in MASH and liver fibrosis in mice. With MASH becoming a global health issue and its progression to fibrosis associated with hepatocarcinogenesis and poor prognosis, understanding the underlying mechanisms is critical. This research contributes to elucidating lncRNA functions in murine liver diseases and provides a foundation for developing novel therapeutic strategies targeting lncRNAs in MASH and liver fibrosis, offering new avenues for potential therapeutic interventions.

Protective Effects of Hepatocyte Stress Defenders, Nrf1 and Nrf2, against MASLD Progression

Progression of metabolic dysfunction-associated steatites liver disease (MASLD) to steatohepatitis (MASH) is driven by stress-inducing lipids that promote liver inflammation and fibrosis, and MASH can lead to cirrhosis and hepatocellular carcinoma. Previously, we showed coordinated defenses regulated by transcription factors, nuclear factor erythroid 2-related factor-1 (Nrf1) and -2 (Nrf2), protect against hepatic lipid stress. Here, we investigated protective effects of hepatocyte Nrf1 and Nrf2 against MASH-linked liver fibrosis and tumorigenesis. Male and female mice with flox alleles for genes encoding Nrf1 (Nfe2l1), Nrf2 (Nfe2l2), or both were fed a MASH-inducing diet enriched with high fat, fructose, and cholesterol (HFFC) or a control diet for 24-52 weeks. During this period, hepatocyte Nrf1, Nrf2, or combined deficiency for ~7 days, ~7 weeks, and ~35 weeks was induced by administering mice hepatocyte-targeting adeno-associated virus (AAV) expressing Cre recombinase. The effects on MASH, markers of liver fibrosis and proliferation, and liver tumorigenesis were compared to control mice receiving AAV-expressing green fluorescent protein. Also, to assess the impact of Nrf1 and Nrf2 induction on liver fibrosis, HFFC diet-fed C57bl/6J mice received weekly injections of carbon tetrachloride, and from week 16 to 24, mice were treated with the Nrf2-activating drug bardoxolone, hepatocyte overexpression of human NRF1 (hNRF1), or both, and these groups were compared to control. Compared to the control diet, 24-week feeding with the HFFC diet increased bodyweight as well as liver weight, steatosis, and inflammation. It also increased hepatocyte proliferation and a marker of liver damage, p62. Hepatocyte Nrf1 and combined deficiency increased liver steatosis in control diet-fed but not HFFC diet-fed mice, and increased liver inflammation under both diet conditions. Hepatocyte Nrf1 deficiency also increased hepatocyte proliferation, whereas combined deficiency did not, and this also occurred for p62 level in control diet-fed conditions. In 52-week HFFC diet-fed mice, 35 weeks of hepatocyte Nrf1 deficiency, but not combined deficiency, resulted in more liver tumors in male mice, but not in female mice. In contrast, hepatocyte Nrf2 deficiency had no effect on any of these parameters. However, in the 15-week CCL4-exposed and 24-week HFFC diet-fed mice, Nrf2 induction with bardoxolone reduced liver steatosis, inflammation, fibrosis, and proliferation. Induction of hepatic Nrf1 activity with hNRF1 enhanced the effect of bardoxolone on steatosis and may have stimulated liver progenitor cells. Physiologic Nrf1 delays MASLD progression, Nrf2 induction alleviates MASH, and combined enhancement synergistically protects against steatosis and may facilitate liver repair.

Exploring Fibrosis Pathophysiology in Lean and Obese Metabolic-Associated Fatty Liver Disease: An In-Depth Comparison

While obesity-related nonalcoholic fatty liver disease (NAFLD) is linked with metabolic dysfunctions such as insulin resistance and adipose tissue inflammation, lean NAFLD more often progresses to liver fibrosis even in the absence of metabolic syndrome. This review aims to summarize the current knowledge regarding the mechanisms of liver fibrosis in lean NAFLD. The most commonly used lean NAFLD models include a methionine/choline-deficient (MCD) diet, a high-fat diet with carbon tetrachloride (CCl4), and a high-fructose and high-cholesterol diet. The major pro-fibrogenic mechanisms in lean NAFLD models include increased activation of the extracellular signal-regulated kinase (ERK) pathway, elevated expression of α-smooth muscle actin (α-SMA), collagen type I, and TGF-β, and modulation of fibrogenic markers such as tenascin-X and metalloproteinase inhibitors. Additionally, activation of macrophage signaling pathways promoting hepatic stellate cell (HSC) activation further contributes to fibrosis development. Animal models cannot cover all clinical features that are evident in patients with lean or obese NAFLD, implicating the need for novel models, as well as for deeper comparisons of clinical and experimental studies. Having in mind the prevalence of fibrosis in lean NAFLD patients, by addressing specific pathways, clinical studies can reveal new targeted therapies along with novel biomarkers for early detection and enhancement of clinical management for lean NAFLD patients.

A novel Alisma orientale extract alleviates non-alcoholic steatohepatitis in mice via modulation of PPARα signaling pathway

Non-alcoholic fatty liver disease (NAFLD), particularly advanced non-alcoholic steatohepatitis (NASH), leads to irreversible liver damage. This study investigated the therapeutic effects and potential mechanism of a novel extract from traditional Chinese medicine Alisma orientale (Sam.) Juzep (AE) on free fatty acid (FFA)-induced HepG2 cell model and high-fat diet (HFD) + carbon tetrachloride (CCl4)-induced mouse model of NASH. C57BL/6 J mice were fed a HFD for 10 weeks. Subsequently, the mice were injected with CCl4 to induce NASH and simultaneously treated with AE at daily doses of 50, 100, and 200 mg/kg for 4 weeks. At the end of the treatment, animals were fasted for 12 h and then sacrificed. Blood samples and liver tissues were collected for analysis. Lipid profiles, oxidative stress, and histopathology were examined. Additionally, a polymerase chain reaction (PCR) array was used to predict the molecular targets and potential mechanisms involved, which were further validated in vivo and in vitro. The results demonstrated that AE reversed liver damage (plasma levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), hepatocyte ballooning, hepatic steatosis, and NAS score), the accumulation of hepatic lipids (TG and TC), and oxidative stress (MDA and GSH). PCR array analysis and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis revealed that AE protects against NASH by regulating the adipocytokine signaling pathway and influencing nuclear receptors such as PPARα. Furthermore, AE increased the expression of peroxisome proliferator-activated receptor gamma coactivator-1α (PPARGC1α) and reversed the decreased expression of PPARα in NASH mice. Moreover, in HepG2 cells, AE reduced FFA-induced lipid accumulation and oxidative stress, which was dependent on PPARα up-regulation. Overall, our findings suggest that AE may serve as a potential therapeutic approach for NASH by inhibiting lipid accumulation and reducing oxidative stress specifically through the PPARα pathway.

Signaling through the nicotinic acetylcholine receptor in the liver protects against the development of metabolic dysfunction-associated steatohepatitis

Metabolic dysfunction-associated steatohepatitis (MASH) is the progressive form of liver steatosis, the most common liver disease, and substantially increases the mortality rate. However, limited therapies are currently available to prevent MASH development. Identifying potential pharmacological treatments for the condition has been hampered by its heterogeneous and complex nature. Here, we identified a hepatic nonneuronal cholinergic signaling pathway required for metabolic adaptation to caloric overload. We found that cholinergic receptor nicotinic alpha 2 subunit (CHRNA2) is highly expressed in hepatocytes of mice and humans. Further, CHRNA2 is activated by a subpopulation of local acetylcholine-producing macrophages during MASH development. The activation of CHRNA2 coordinates defensive programs against a broad spectrum of MASH-related pathogenesis, including steatosis, inflammation, and fibrosis. Hepatocyte-specific loss of CHRNA2 signaling accelerates the disease onset in different MASH mouse models. Activation of this pathway via pharmacological inhibition of acetylcholine degradation protects against MASH development. Our study uncovers a hepatic nicotinic cholinergic receptor pathway that constitutes a cell-autonomous self-defense route against prolonged metabolic stress and holds therapeutic potential for combatting human MASH.

A short-term rodent model for non-alcoholic steatohepatitis induced by a high-fat diet and carbon tetrachloride

Several models of mice-fed high-fat diets have been used to trigger non-alcoholic steatohepatitis and some chemical substances, such as carbon tetrachloride. The present study aimed to evaluate the joint action of a high-fat diet and CCl4 in developing a short-term non-alcoholic steatohepatitis model. C57BL6/J mice were divided into two groups: standard diet-fed (SD), the high-fat diet-fed (HFD) and HFD + fructose-fed and carbon tetrachloride (HFD+CCl4). The animals fed with HFD+CCl4 presented increased lipid deposition compared with both SD and HFD mice. Plasma cholesterol was increased in animals from the HFD+CCl4 group compared with the SD and HFD groups, without significant differences between the SD and HFD groups. Plasma triglycerides showed no significant difference between the groups. The HFD+CCl4 animals had increased collagen deposition in the liver compared with both SD and HFD groups. Hydroxyproline was also increased in the HFD+CCl4 group. Liver enzymes, alanine aminotransferase and aspartate aminotransferase, were increased in the HFD+CCl4 group, compared with SD and HFD groups. Also, CCl4 was able to trigger an inflammatory process in the liver of HFD-fed animals by promoting an increase of ∼2 times in macrophage activity, ∼6 times in F4/80 gene expression, and pro-inflammatory cytokines (IL-1b and TNFa), in addition to an increase in inflammatory pathway protein phosphorylation (IKKbp). HFD e HFD+CCl4 animals increased glucose intolerance compared with SD mice, associated with reduced insulin-stimulated AKT activity in the liver. Therefore, our study has shown that short-term HFD feeding associated with fructose and CCl4 can trigger non-alcoholic steatohepatitis and cause damage to glucose metabolism.

TM7SF3 controls TEAD1 splicing to prevent MASH-induced liver fibrosis

The mechanisms of hepatic stellate cell (HSC) activation and the development of liver fibrosis are not fully understood. Here, we show that deletion of a nuclear seven transmembrane protein, TM7SF3, accelerates HSC activation in liver organoids, primary human HSCs, and in vivo in metabolic-dysfunction-associated steatohepatitis (MASH) mice, leading to activation of the fibrogenic program and HSC proliferation. Thus, TM7SF3 knockdown promotes alternative splicing of the Hippo pathway transcription factor, TEAD1, by inhibiting the splicing factor heterogeneous nuclear ribonucleoprotein U (hnRNPU). This results in the exclusion of the inhibitory exon 5, generating a more active form of TEAD1 and triggering HSC activation. Furthermore, inhibiting TEAD1 alternative splicing with a specific antisense oligomer (ASO) deactivates HSCs in vitro and reduces MASH diet-induced liver fibrosis. In conclusion, by inhibiting TEAD1 alternative splicing, TM7SF3 plays a pivotal role in mitigating HSC activation and the progression of MASH-related fibrosis.

Pharmacokinetic Effects of Different Models of Nonalcoholic Fatty Liver Disease in Transgenic Humanized OATP1B Mice

Organic anion transporting polypeptide (OATP) 1B1 and OATP1B3 (collectively, OATP1B) transporters encoded by the solute carrier organic anion transporter (SLCO) genes mediate uptake of multiple pharmaceutical compounds. Nonalcoholic steatohepatitis (NASH), a severe form of nonalcoholic fatty liver disease (NAFLD), decreases OATP1B abundance. This research characterized the pathologic and pharmacokinetics effects of three diet- and one chemical-induced NAFLD model in male and female humanized OATP1B mice, which comprises knock-out of rodent Oatp orthologs and insertion of human SLCO1B1 and SLCO1B3. Histopathology scoring demonstrated elevated steatosis and inflammation scores for all NAFLD-treatment groups. Female mice had minor changes in SLCO1B1 expression in two of the four NAFLD treatment groups, and pitavastatin (PIT) area under the concentration-time curve (AUC) increased in female mice in only one of the diet-induced models. OATP1B3 expression decreased in male and female mice in the chemical-induced NAFLD model, with a coinciding increase in PIT AUC, indicating the chemical-induced model may better replicate changes in OATP1B3 expression and OATP substrate disposition observed in NASH patients. This research also tested a reported multifactorial pharmacokinetic interaction between NAFLD and silymarin, an extract from milk thistle seeds with notable OATP-inhibitory effects. Males showed no change in PIT AUC, whereas female PIT AUC increased 1.55-fold from the diet alone and the 1.88-fold from the combination of diet with silymarin, suggesting that female mice are more sensitive to pharmacokinetic changes than male mice. Overall, the humanized OATP1B model should be used with caution for modeling NAFLD and multifactorial pharmacokinetic interactions. SIGNIFICANCE STATEMENT: Advanced stages of NAFLD cause decreased hepatic OATP1B abundance and increase systemic exposure to OATP substrates in human patients. The humanized OATP1B mouse strain may provide a clinically relevant model to recapitulate these observations and predict pharmacokinetic interactions in NAFLD. This research characterized three diet-induced and one drug-induced NAFLD model in a humanized OATP1B mouse model. Additionally, a multifactorial pharmacokinetic interaction was observed between silymarin and NAFLD.

Transcriptomics-driven metabolic pathway analysis reveals similar alterations in lipid metabolism in mouse MASH model and human

BACKGROUND

Metabolic dysfunction-associated steatotic liver disease (MASLD) is a prevalent chronic liver disease worldwide, and can rapidly progress to metabolic dysfunction-associated steatohepatitis (MASH). Accurate preclinical models and methodologies are needed to understand underlying metabolic mechanisms and develop treatment strategies. Through meta-analysis of currently proposed mouse models, we hypothesized that a diet- and chemical-induced MASH model closely resembles the observed lipid metabolism alterations in humans.

METHODS

We developed transcriptomics-driven metabolic pathway analysis (TDMPA), a method to aid in the evaluation of metabolic resemblance. TDMPA uses genome-scale metabolic models to calculate enzymatic reaction perturbations from gene expression data. We performed TDMPA to score and compare metabolic pathway alterations in MASH mouse models to human MASH signatures. We used an already-established WD+CCl4-induced MASH model and performed functional assays and lipidomics to confirm TDMPA findings.

RESULTS

Both human MASH and mouse models exhibit numerous altered metabolic pathways, including triglyceride biosynthesis, fatty acid beta-oxidation, bile acid biosynthesis, cholesterol metabolism, and oxidative phosphorylation. We confirm a significant reduction in mitochondrial functions and bioenergetics, as well as in acylcarnitines for the mouse model. We identify a wide range of lipid species within the most perturbed pathways predicted by TDMPA. Triglycerides, phospholipids, and bile acids are increased significantly in mouse MASH liver, confirming our initial observations.

CONCLUSIONS

We introduce TDMPA, a methodology for evaluating metabolic pathway alterations in metabolic disorders. By comparing metabolic signatures that typify human MASH, we show a good metabolic resemblance of the WD+CCl4 mouse model. Our presented approach provides a valuable tool for defining metabolic space to aid experimental design for assessing metabolism.

Novel insights into metabolic-associated steatotic liver disease preclinical models

Metabolic-associated steatotic liver disease (MASLD) encompasses a wide spectrum of metabolic conditions associated with an excess of fat accumulation in the liver, ranging from simple hepatic steatosis to cirrhosis and hepatocellular carcinoma. Finding appropriate tools to study its development and progression is essential to address essential unmet therapeutic and staging needs. This review discusses advantages and shortcomings of different dietary, chemical and genetic factors that can be used to mimic this disease and its progression in mice from a hepatic and metabolic point of view. Also, this review will highlight some additional factors and considerations that could have a strong impact on the outcomes of our model to end up providing recommendations and a checklist to facilitate the selection of the appropriate MASLD preclinical model based on clinical aims.

Ginsenoside Rg5 inhibits lipid accumulation and hepatocyte apoptosis via the Notch1 signaling pathway in NASH mice

BACKGROUND

Non-alcoholic steatohepatitis (NASH) is a prevalent chronic liver disease that lacks an FDA-approved treatment medicine. Despite the known antitumor and hypoglycemic properties of Ginsenoside Rg5, its effects and underlying mechanisms in the context of NASH remain largely unexplored.

PURPOSE

This study aims to investigate the effect of Rg5 on NASH mice induced by a high-fat diet and CCl4.

STUDY DESIGN

In vivo experiments, a mouse NASH model was established by a HFHC diet plus intraperitoneal injection of low-dose CCl4. In vitro experiments, a cellular steatosis model was established using free fatty acids (FFA) induced HepG2 cells. In addition, a fibrogenesis model was established using HSC-LX2 cells.

METHODS

The effects of Ginsenoside Rg5 on lipid accumulation and oxidative damage were analyzed by ELISA kit, H&E staining, Oil Red O staining, flow cytometry and Western blot. The effects of Ginsenoside Rg5 on liver fibrosis were analyzed by Masson staining, Sirus Red staining, immunohistochemistry and Western blot. The effect of Ginsenoside Rg5 on Notch1 signaling pathway in liver was studied by protein Oil Red staining, protein immunoblotting and immunofluorescence.

RESULTS

In terms of lipid accumulation, Rg5 has the ability to regulate key proteins related to lipogenesis, thereby inhibiting hepatic lipid accumulation and oxidative stress. Additionally, Rg5 can reduce the occurrence of hepatocyte apoptosis by regulating the p53 protein. Moreover, after Rg5 intervention, the presence of fibrotic proteins (α-SMA, Collagen 1, TGF-β) in the liver is significantly suppressed, thus inhibiting liver fibrosis. Lastly, Rg5 leads to a decrease in the expression levels of Notch1 and its ligand Jagged-1 in the liver.

CONCLUSION

In summary, the regulatory effects of Rg5 on the Notch1 signaling pathway play a crucial role in modulating hepatic lipid metabolism and preventing hepatocyte apoptosis, thereby impeding the progression of NASH. These findings highlight the potential of Rg5 as a promising natural product for interventions targeting NASH.

FGF9 Recruits β-Catenin to Increase Hepatic ECM Synthesis and Promote NASH-Driven HCC

Most nonalcoholic steatohepatitis (NASH) patients develop severe fibrosis through extracellular matrix (ECM) accumulation, which can lead to hepatocellular carcinoma (HCC). Fibroblast growth factor 9 (FGF9) is involved in serial types of cancer; however, the specific role of FGF9 in NASH-driven HCC is not fully understood. This study finds that FGF9 is increased in patients with NASH-associated HCC. Furthermore, NASH-driven HCC mice models by feeding wildtype mice with high-fat/high-cholesterol (HFHC) diet and low dose carbon tetrachloride (CCl4 ) treatment is established; and identified that hepatic FGF9 is increased; with severe fibrosis. Additionally, AAV-mediated knockdown of FGF9 reduced the hepatic tumor burden of NASH-driven HCC mice models. Hepatocyte-specific FGF9 transgenic mice (FGF9Alb ) fed with a HFHC diet without CCl4 treatment exhibited an increased hepatic ECM and tumor burden. However, XAV-939 treatment blocked ECM accumulation and NASH-driven HCC in FGF9Alb mice fed with HFHC diet. Molecular mechanism studies show that FGF9 stimulated the expression of ECM related genes in a β-catenin dependent manner; and FGF9 exerts its effect on β-catenin stability via the ERK1/2-GSK-3β signaling pathway. In summary, the data provides evidence for the critical role of FGF9 in NASH-driven HCC pathogenesis; wherein it promotes the tumors formation through the ECM pathway.

Isolation, culture, and delivery considerations for the use of mesenchymal stem cells in potential therapies for acute liver failure

Acute liver failure (ALF) is a high-mortality syndrome for which liver transplantation is considered the only effective treatment option. A shortage of donor organs, high costs and surgical complications associated with immune rejection constrain the therapeutic effects of liver transplantation. Recently, mesenchymal stem cell (MSC) therapy was recognized as an alternative strategy for liver transplantation. Bone marrow mesenchymal stem cells (BMSCs) have been used in clinical trials of several liver diseases due to their ease of acquisition, strong proliferation ability, multipotent differentiation, homing to the lesion site, low immunogenicity and anti-inflammatory and antifibrotic effects. In this review, we comprehensively summarized the harvest and culture expansion strategies for BMSCs, the development of animal models of ALF of different aetiologies, the critical mechanisms of BMSC therapy for ALF and the challenge of clinical application.

Macrophages and the development and progression of non-alcoholic fatty liver disease

The liver is the site of first pass metabolism, detoxifying and metabolizing blood arriving from the hepatic portal vein and hepatic artery. It is made up of multiple cell types, including macrophages. These are either bona fide tissue-resident Kupffer cells (KC) of embryonic origin, or differentiated from circulating monocytes. KCs are the primary immune cells populating the liver under steady state. Liver macrophages interact with hepatocytes, hepatic stellate cells, and liver sinusoidal endothelial cells to maintain homeostasis, however they are also key contributors to disease progression. Generally tolerogenic, they physiologically phagocytose foreign particles and debris from portal circulation and participate in red blood cell clearance. However as immune cells, they retain the capacity to raise an alarm to recruit other immune cells. Their aberrant function leads to the development of non-alcoholic fatty liver disease (NAFLD). NAFLD refers to a spectrum of conditions ranging from benign steatosis of the liver to steatohepatitis and cirrhosis. In NAFLD, the multiple hit hypothesis proposes that simultaneous influences from the gut and adipose tissue (AT) generate hepatic fat deposition and that inflammation plays a key role in disease progression. KCs initiate the inflammatory response as resident immune effectors, they signal to neighbouring cells and recruit monocytes that differentiated into recruited macrophages in situ. Recruited macrophages are central to amplifying the inflammatory response and causing progression of NAFLD to its fibro-inflammatory stages. Given their phagocytic capacity and their being instrumental in maintaining tissue homeostasis, KCs and recruited macrophages are fast-becoming target cell types for therapeutic intervention. We review the literature in the field on the roles of these cells in the development and progression of NAFLD, the characteristics of patients with NAFLD, animal models used in research, as well as the emerging questions. These include the gut-liver-brain axis, which when disrupted can contribute to decline in function, and a discussion on therapeutic strategies that act on the macrophage-inflammatory axis.

Collagen co-localized with macrovesicular steatosis better differentiates fibrosis progression in non-alcoholic fatty liver disease mouse models

Background

Non-alcoholic fatty liver disease (NAFLD) is a global commonly occurring liver disease. However, its exact pathogenesis is not fully understood. The purpose of this study was to quantitatively evaluate the progression of steatosis and fibrosis by examining their distribution, morphology, and co-localization in NAFLD animal models.

Methods

Six mouse NAFLD groups were established: (1) western diet (WD) group; (2) WD with fructose in drinking water (WDF) group; (3) WDF + carbon tetrachloride (CCl4) group, WDF plus intraperitoneal injection of CCl4; (4) high-fat diet (HFD) group, (5) HFD with fructose (HFDF) group; and (6) HFDF + CCl4 group, HFDF plus intraperitoneal injection of CCl4. Liver tissue specimens from NAFLD model mice were collected at different time points. All the tissues were serially sectioned for histological staining and second-harmonic generation (SHG)/two-photon excitation fluorescence imaging (TPEF) imaging. The progression of steatosis and fibrosis was analyzed using SHG/TPEF quantitative parameters with respect to the non-alcoholic steatohepatitis Clinical Research Network scoring system.

Results

qSteatosis showed a good correlation with steatosis grade (R: 0.823-0.953, p < 0.05) and demonstrated high performance (area under the curve [AUC]: 0.617-1) in six mouse models. Based on their high correlation with histological scoring, qFibrosis containing four shared parameters (#LongStrPS, #ThinStrPS, #ThinStrPSAgg, and #LongStrPSDis) were selected to create a linear model that could accurately identify differences among fibrosis stages (AUC: 0.725-1). qFibrosis co-localized with macrosteatosis generally correlated better with histological scoring and had a higher AUC in six animal models (AUC: 0.846-1).

Conclusion

Quantitative assessment using SHG/TPEF technology can be used to monitor different types of steatosis and fibrosis progression in NAFLD models. The collagen co-localized with macrosteatosis could better differentiate fibrosis progression and might aid in developing a more reliable and translatable fibrosis evaluation tool for animal models of NAFLD.

Neferine ameliorates nonalcoholic steatohepatitis through regulating AMPK pathway

BACKGROUND

Nonalcoholic fatty liver disease (NAFLD), peculiarly nonalcoholic steatohepatitis (NASH), has become the main cause of liver transplantation and liver-related death. However, the US Food and Drug Administration has not approved a specific medication for treating NASH. Neferine (NEF), a natural bisbenzylisoquinoline alkaloid separated from the traditional Chinese medicine Nelumbinis plumula, has a variety of pharmacological properties, especially on metabolic diseases. Nevertheless, the anti-NASH effect and mechanisms of NEF remain unclear.

PURPOSE

This study aimed to investigate the amelioration of NEF on NASH and the potential mechanisms.

STUDY DESIGN

HepG2 cells, hepatic stellate cells (HSCs) and high-fat diet (HFD)+carbon tetrachloride (CCl₄) induced C57BL/6 mice were used to observe the effect of NEF against NASH and investigate the engaged mechanism.

METHODS

HSCs and HepG2 cells stimulated by oleic acid (OA) were treated with NEF. C57BL/6 mice were fed with HFD+CCl₄ to induce NASH mouse model and treated with or without NEF (5 mg/kg or 10 mg/kg, once daily, i.p) for 4 weeks.

RESULTS

NEF significantly attenuated the accumulation of lipid droplets, intracellular triglyceride (TG) levels and hepatocytes apoptosis in OA-exposed HepG2 cells. NEF not only enhanced the AMPK and ACC phosphorylation in OA-stimulated HepG2 cells, but also reduced inflammatory response and fibrosis in lipopolysaccharide (LPS)-stimulated HepG2 and in LX-2, respectively. In HFD+CCl₄-induced NASH mice, pathological staining confirmed NEF treatment mitigated hepatic lipid deposition, inflammatory cell infiltration as well as hepatic fibrosis. Furthermore, the liver weight, serum and hepatic TG and total cholesterol (TC) and aspartate aminotransferase (AST) and alanine aminotransferase (ALT) were decreased compared with the model group. HFD+CCl₄ also induced the upregulation of specific proteins and genes associated to inflammation (ILs, TNF-α, NLRP3, ASC, CCL2 and CXCL10) and hepatic fibrosis (collagens, α-SMA, TGF-β and TIPM1), which were also suppressed by NEF treatment.

CONCLUSION

Our results demonstrated that NEF played a protective role in hepatic steatosis via the regulation of AMPK pathways, which may serve as an attractive candidate for a potential novel strategy on prevention and treatment of NASH.

Role of B Cell-Activating Factor in Fibrosis Progression in a Murine Model of Non-Alcoholic Steatohepatitis

Non-alcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease all over the world. Therapeutic strategies targeting its multidirectional pathways are required. Particularly, fibrosis is closely associated with its prognosis. We previously found that B cell-activating factor (BAFF) is associated with severity of NAFLD. Here, we determined the direct in vivo role of BAFF in the development of liver fibrosis. Histological and biochemical analyses were performed using wild-type and BAFF-deficient mice. We established a murine model of non-alcoholic steatohepatitis (NASH) using carbon tetrachloride injection accompanied by high-fat/high-cholesterol diet feeding. Additionally, in vitro analysis using mouse macrophage-like cell line RAW264.7 and primary hepatic stellate cells was performed. Hepatic steatosis and inflammation, and most importantly, the progression of liver fibrosis, were ameliorated in BAFF-deficient mice compared to those wild-type mice in our model. Additionally, BAFF deficiency reduced the number of CD11c⁺ M1-type macrophages in the liver. Moreover, BAFF stimulated RAW264.7 cells to secrete nitric oxide and tumor necrosis factor α, which drove the activation of hepatic stellate cells. This indicates that BAFF plays a crucial role in NASH development and may be a promising therapeutic target for NASH.

An update on animal models of liver fibrosis

The development of liver fibrosis primarily determines quality of life as well as prognosis. Animal models are often used to model and understand the underlying mechanisms of human disease. Although organoids can be used to simulate organ development and disease, the technology still faces significant challenges. Therefore animal models are still irreplaceable at this stage. Currently, in vivo models of liver fibrosis can be classified into five categories based on etiology: chemical, dietary, surgical, transgenic, and immune. There is a wide variety of animal models of liver fibrosis with varying efficacy, which have different implications for proper understanding of the disease and effective screening of therapeutic agents. There is no high-quality literature recommending the most appropriate animal models. In this paper, we will describe the progress of commonly used animal models of liver fibrosis in terms of their development mechanisms, applications, advantages and disadvantages, and recommend appropriate animal models for different research purposes.

Antioxidant and Hepatoprotective Activities of Acacia jacquemontii Stem Extract against High-fat and CCl4-induced Liver Injury in Rat's Model

BACKGROUND

Chronic liver injury leads to liver inflammation and fibrosis, activating myofibroblasts in the liver and secreting extracellular matrix proteins that make the fibrous scar.

OBJECTIVES

The purpose of our study was to characterize the polyphenolic content present in Acacia jacquemontii stem and evaluate its antioxidant and hepatoprotective activity.

METHODS

The phenolic contents in Acacia jacquemontii polyphenolic extract (AJPPE) were characterized using high-performance liquid chromatography (HPLC). The hepatoprotective and antioxidant activity of AJPPE were determined through biochemical parameters (ALT, AST, and ALP), lipid profile (TC, TG, HDL, and LDL), antioxidant biomarkers (SOD, LPO, GSH, and CAT), anti-fibrotic activity (collagen deposition), and histopathological analysis.

RESULTS

HPLC analysis of AJPPE showed the presence of polyphenols, including chlorogenic acid, P-coumaric acid, caffeic acid, and kaempferol, in a remarkable therapeutic range. Results of the in vivo analysis showed a significant decrease in the level of lipid profile, including LDL (low-density lipoprotein), TC (total cholesterol), triglycerides, liver function markers (AST, ALT, and ALP), collagen deposition and significantly increased the level of anti-oxidative biomarkers (CAT, SOD, LPO, and GSH) by using AJPPE.

CONCLUSION

The above-mentioned results have shown that AJPPE possesses significant antioxidative and hepatoprotective effects. Furthermore, histopathological results also supported the antioxidant and hepatoprotective potential of AJPPE.

Metabolic improvement and liver regeneration by inhibiting CXXC5 function for non-alcoholic steatohepatitis treatment

Non-alcoholic steatohepatitis (NASH) is a chronic liver disease that results from multiple metabolic disorders. Considering the complexity of the pathogenesis, the identification of a factor mediating the multiple pathogenic phenotypes of NASH will be important for treatment. In this study, we found that CXXC5, a negative feedback regulator of the Wnt/β-catenin pathway, was overexpressed with suppression of Wnt/β-catenin signaling and its target genes involved in hepatic metabolism in obese-NASH patients. Cxxc5−/− mice were found to be resistant to NASH pathogenesis with metabolic improvements. KY19334, a small molecule that activates the Wnt/β-catenin pathway via interference of the CXXC5-Dvl interaction, reversed the overall pathogenic features of NASH as Cxxc5−/− mice. The improvement in NASH by KY19334 is attributed to its regenerative effects through restorative activation of the suppressed Wnt/β-catenin signaling. Overall, the pronounced metabolic improvements with the stimulation of liver regeneration by interfering with the CXXC5-Dvl interaction provide a therapeutic approach for NASH.

Amelioration of high-fat diet (HFD) + CCl4 induced NASH/NAFLD in CF-1 mice by activation of SIRT-1 using cinnamoyl sulfonamide hydroxamate derivatives: in-silico molecular modelling and in-vivo prediction

Non-alcoholic fatty liver disease (NAFLD) is one of the major hepatic metabolic disorders that occurs because of the accumulation of lipids in hepatocytes in the form of free fatty acids (FFA) and triglycerides (TG) which become non-alcoholic steatohepatitis (NASH). NOTCH-1 receptors act as novel targets for the development of NAFLD/NASH, where overexpression of NOTCH-1 receptor alters the lipid metabolism in hepatocytes leading to NAFLD. SIRT-1 deacetylates the NOTCH-1 receptor and inhibits NAFLD. Hence, computer-aided drug design (CADD) was used to check the SIRT-1 activation ability of cinnamic sulfonyl hydroxamate derivatives (NMJ 1–8), resveratrol, and vorinostat. SIRT-1 (PDB ID: 5BTR) was docked with eight hydroxamate derivatives and vorinostat using Schrödinger software. Based on binding energy obtained (– 26.31 to – 47.34 kcal/mol), vorinostat, NMJ-2, NMJ-3, NMJ-5 were selected for induced-fit docking (IFD) and results were within – 750.70 to – 753.22 kcal/mol. Qikprop tool was used to analyse the pre pharmacokinetic parameters (ADME analysis) of all hydroxamate compounds. As observed in the molecular dynamic (MD) study, NMJ-2, NMJ-3 were showing acceptable results for activation of SIRT-1. Based on these predictions, in-vivo studies were conducted in CF1 mice, where NMJ-3 showed significant (p < 0.05) changes in lipid profile and anti-oxidant parameters (Catalase, SOD, GSH, nitrite, and LPO) and plasma insulin levels. NMJ-3 treatment also reduced inflammation, fibrosis, and necrosis in liver samples.

Proteomic analysis reveals USP7 as a novel regulator of palmitic acid-induced hepatocellular carcinoma cell death

Nutrient surplus and consequent free fatty acid accumulation in the liver cause hepatosteatosis. The exposure of free fatty acids to cultured hepatocyte and hepatocellular carcinoma cell lines induces cellular stress, organelle adaptation, and subsequent cell death. Despite many studies, the mechanism associated with lipotoxicity and subsequent cell death still remains poorly understood. Here, we have used the proteomics approach to circumvent the mechanism for lipotoxicity using hepatocellular carcinoma cells as a model. Our quantitative proteomics data revealed that ectopic lipids accumulation in cells severely affects the ubiquitin-proteasomal system. The palmitic acid (PA) partially lowered the expression of deubiquitinating enzyme USP7 which subsequently destabilizes p53 and promotes mitotic entry of cells. Our global phosphoproteomics analysis also provides strong evidence of an altered cell cycle checkpoint proteins' expression that abrogates early G2/M checkpoints recovery with damaged DNA and induced mitotic catastrophe leading to hepatocyte death. We observe that palmitic acid prefers apoptosis-inducing factor (AIF) mediated cell death by depolarizing mitochondria and translocating AIF to the nucleus. In summary, the present study provides evidence of PA-induced hepatocellular death mediated by deubiquitinase USP7 downregulation and subsequent mitotic catastrophe.

Identification of Hub Genes Associated With Non-alcoholic Steatohepatitis Using Integrated Bioinformatics Analysis

Background and aims: As a major cause of liver disease worldwide, non-alcoholic fatty liver disease (NAFLD) comprises non-alcoholic fatty liver (NAFL) and non-alcoholic steatohepatitis (NASH). Due to the high prevalence and poor prognosis of NASH, it is critical to understand its mechanisms. However, the etiology and mechanisms remain largely unknown. In addition, the gold standard for the diagnosis of NASH is liver biopsy, which is an invasive procedure. Therefore, there is a pressing need to develop noninvasive tests for NASH diagnosis. The goal of the study is to discover key genes involved in NASH development and investigate their value as noninvasive biomarkers.

Methods: The Gene Expression Omnibus (GEO) database was used to obtain two datasets encompassing NASH patients and healthy controls. We used weighted gene co-expression network analysis (WGCNA) and differential expression analysis in order to investigate the association between gene sets and clinical features, as well as to discover co-expression modules. A protein-protein interaction (PPI) network was created to extract hub genes. The results were validated using another publicly available dataset and mice treated with a high-fat diet (HFD) and carbon tetrachloride (CCl4).

Results: A total of 24 differentially co-expressed genes were selected by WGCNA and differential expression analysis. KEGG analysis indicated most of them were enriched in the focal adhesion pathway. GO analysis showed these genes were mainly enriched in circadian rhythm, aging, angiogenesis and response to drug (biological process), endoplasmic reticulum lumen (cellular component), and protein binding (molecular function). As a result, eight genes (JUN, SERPINE1, GINS2, TYMS, HMMR, IGFBP2, BIRC3, TNFRSF12A) were identified as hub genes. Finally, three genes were found significantly changed in both the validation dataset and the mouse model.

Conclusion: Our research discovered genes that have the potential to mediate the process of NASH and might be useful diagnostic biomarkers for the disorder.

Induction of Accelerated Aging in a Mouse Model

With the global increase of the elderly population, the improvement of the treatment for various aging-related diseases and the extension of a healthy lifespan have become some of the most important current medical issues. In order to understand the developmental mechanisms of aging and aging-related disorders, animal models are essential to conduct relevant studies. Among them, mice have become one of the most prevalently used model animals for aging-related studies due to their high similarity to humans in terms of genetic background and physiological structure, as well as their short lifespan and ease of reproduction. This review will discuss some of the common and emerging mouse models of accelerated aging and related chronic diseases in recent years, with the aim of serving as a reference for future application in fundamental and translational research.

The anti-inflammatory effects of Akkermansia muciniphila and its derivates in HFD/CCL4-induced murine model of liver injury

Inflammation plays a critical role in the promotion of hepatocyte damage and liver fibrosis. In recent years the protective role of Akkermansia muciniphila, a next-generation beneficial microbe, has been suggested for metabolic and inflammatory disorders. In this study, we aimed to evaluate the effects of live and pasteurized A. muciniphila and its extra cellular vesicles (EVs) on inflammatory markers involved in liver fibrosis in a mouse model of a high-fat diet (HFD)/carbon tetrachloride (CCl₄)-induced liver injury. Firstly, the responses of hepatic stellate cells (HSCs) to live and pasteurized A. muciniphila and its EVs were examined in the quiescent and LPS-activated LX-2 cells. Next, the anti-inflammatory effects of different forms of A. muciniphila were examined in the mouse model of HFD/CCl₄-induced liver injury. The gene expression of various inflammatory markers was evaluated in liver, colon, and white adipose tissues. The cytokine secretion in the liver and white adipose tissues was also measured by ELISA. The results showed that administration of live and pasteurized A. muciniphila and its EVs leads to amelioration in HSCs activation. Based on data obtained from the histopathological analysis, an improvement in gut health was observed through enhancing the epithelium and mucosal layer thickness and strengthening the intestinal integrity in all treatments. Moreover, live A. muciniphila and its EVs had inhibitory effects on liver inflammation and hepatocytes damage. In addition, the tissue cytokine production and inflammatory gene expression levels revealed that live A. muciniphila and its EVs had more pronounced anti-inflammatory effects on liver and adipose tissues. Furthermore, EVs had better effects on the modulation of gene expression related to TLRs, PPARs, and immune response in the liver. In conclusion, the present results showed that oral administration of A. muciniphila and its derivatives for four weeks could enhance the intestinal integrity and anti-inflammatory responses of the colon, adipose, and liver tissues and subsequently prevent liver injury in HFD/CCL₄ mice.

Generation of a Diet-Induced Mouse Model of Nonalcoholic Fatty Liver Disease

The obesity epidemic is driving the increased prevalence of nonalcoholic fatty liver disease (NAFLD) globally. The more aggressive subtype of NAFLD, nonalcoholic steatohepatitis (NASH), can lead to progressive disease and ultimately lead to cirrhosis, liver cancer, and death. There are many unmet needs in the field of NAFLD including understanding of molecular mechanisms driving disease, natural history, risk for liver cancer, and most importantly FDA approved therapeutics. Animal models serve as a tool to aid in answering some of these questions. Here, we describe the diet-induced animal model of NAFLD (DIAMOND), a mouse model with many characteristics that mimic human NASH.

CCl4 inhibits the expressions of hepatic taurine biosynthetic enzymes and taurine synthesis in the progression of mouse liver fibrosis

Carbon tetrachloride (CCl4) is a widely used hepatotoxin for the studies of liver fibrosis and cirrhosis, and taurine has function to abate liver fibrosis induced by CCl4. But the interacting mechanisms between taurine and CCl4 in liver are still largely unknown. These made us to hypothesize that CCl4 may induce liver fibrosis by affecting the expressions of taurine biosynthetic enzymes and taurine synthesis. We thus assayed the expressions of hepatic cysteine dioxygenase (CDO), cysteine sulfonate acid decarboxylase (CSAD) and taurine transporter (TauT) in the progression of mouse liver fibrosis induced by CCl4. The results demonstrated that CCl4 treatment markedly decreased hepatic CSAD, CDO expressions, and taurine levels in hepatic tissue, although TauT expression did not exhibit significant decline. It was contrasting that hepatic α-SMA, serum AST, ALT, ALP kept increasing, which were accompanied by the pathological characters of liver, whereas taurine supplement attenuated the progression of liver fibrosis induced by CCl4. These results demonstrate that CCl4 may induce liver fibrosis by inhibiting hepatic CSAD and CDO expressions and taurine synthesis, which are crucial for our understanding the mechanisms of liver fibrosis induced by CCl4, and also potential for establishing therapeutic strategies of liver fibrosis and related diseases.

An Efficient Model of Non-alcoholic Fatty Liver Disease (NAFLD) Versus Current Experimental Models: Effects of Fructose, Fat, and Carbon Tetrachloride on NAFLD

Background: Accumulation of fat in the liver is one of the causes of non-alcoholic fatty liver disease (NAFLD), which affects about 30% of the world's population. Animal models have been useful tools for investigating the mechanisms involved in the etiology of NAFLD and developing new drugs. Objectives: This study aimed to present a new model for the detection of NAFLD in rats. Methods: Forty-eight rats were randomly divided into six experimental groups: (1) control; (2) 45% fructose + 35% olive oil + carbon tetrachloride (FFC1); (3) carbon tetrachloride (1: 4 in olive oil) (C1); (4) carbon tetrachloride (1: 6 in olive oil) (C2); (5) 12.5% fructose + 12.5% olive oil (FF); and (6) 20% fructose + carbon tetrachloride (1: 4 in olive oil) (FC1). Blood samples were taken in three steps, and liver tissue was dissected at the end of the sixth week for histopathological assessments. Results: After six weeks, the alanine transaminase (131.63 ± 1.51), aspartate transaminase (275 ± 1.0), and gamma-glutamyl transferase (4.30 ± 0.1) levels increased significantly in the C1 group (P < 0.05). The serum lipid profile showed significant changes in all groups compared to the controls (P < 0.01). According to the histological results, all experimental groups, except the C2 group, showed symptoms of NAFLD; nevertheless, a higher NAFLD Activity Score (NAS) was found in the C1 group, followed by the FC1 group, compared to the other groups. Conclusions: The present results revealed that injection of 0.1 mL/kg of carbon tetrachloride (C1 group), alone or along with a diet containing 20% fructose (FC1 group), provided useful animal models of NAFLD, although carbon tetrachloride injection alone is the most effective model in inducing NAFLD model that can be used as a new strategy in nutritional and pharmacological studies.

A new mechanism of obeticholic acid on NASH treatment by inhibiting NLRP3 inflammasome activation in macrophage

OBJECTIVE

Obeticholic acid (OCA) has been proved to play potential therapeutic effect on nonalcoholic steatohepatitis (NASH). Up to now, the study of OCA on NLRP3 inflammasome activation in macrophage is still blank and merits great attention. Here, we aimed to better characterize the role and mechanism of OCA on NASH treatment focusing on NLRP3 inflammasome activation in macrophages.

METHODS

The effects of OCA on inflammasome activation were investigated in BMDM, Kupffer cell, BMDC and LX2 cell. Preconditioned media from BMDM culture was used to treat primary hepatocytes to explore the effects of macrophage NLRP3 inflammasome activation on the function of hepatocytes. In vivo, high fat diet plus CCl₄ (DIO + CCl₄) induced murine NASH model and choline-deficient and amino acid-defined (CDA) diet-induced NASH mice were used to verify the inhibitory effect of OCA on inflammasome activation in liver macrophages and recapitulate its protective role on NASH progressing. To clear up the effect of OCA on macrophage is FXR dependent or not, FXR siRNA was introduced into BMDMs.

RESULTS

OCA blockaded NLRP3 inflammasome in BMDMs by impacting on the activation stage and disrupting ASC oligomerization. Preconditioned supernatant from LPS + ATP treated BMDMs increased mRNA expression of lipogenic enzymes and lipid content, whereas preconditioned supernatant from OCA treated BMDM blocked these effects in both normal and the FXR knockdown hepatocytes. In DIO + CCl₄ mice, the population of inflammatory myeloid lineage cells in livers was decreased upon OCA treatment. Accordingly, the level of IL-1β and IL-18 in liver, the hepatic expression of ASC, pro-caspase-1 and active caspase-1, the expression of caspase 1 p20 in liver macrophages were also reduced. Similar results were obtained in CDA diet-fed mice. Furthermore, OCA maintained the inhibition on NLRP3 inflammasome activation in FXR knockdown BMDMs, suggesting FXR could be dispensable in this effect.

CONCLUSIONS

This finding brings up a new mechanism of OCA on NASH treatment, suggested by direct inhibition on NLRP3 inflammasome activation in macrophage, further suppression on inflammasome activation-elicited hepatic lipid accumulation, and contributing to the amelioration of NASH.

Metabolomic Study of High-Fat Diet-Induced Obese (DIO) and DIO Plus CCl4-Induced NASH Mice and the Effect of Obeticholic Acid

The pathophysiology of nonalcoholic fatty liver disease (NAFLD) is a complex process involving metabolic and inflammatory changes in livers and other organs, but the pathogenesis is still not well clarified. Two mouse models were established to study metabolic alteration of nonalcoholic fatty liver and nonalcoholic steatohepatitis, respectively. The concentrations of metabolites in serum, liver and intestine content were measured by the AbsoluteIDQ^® p180 Kit (Biocrates Life Sciences, Innsbruck, Austria). Multivariate statistical methods, pathway analysis, enrichment analysis and correlation analysis were performed to analyze metabolomic data. The metabolic characteristics of liver, serum and intestine content could be distinctly distinguished from each group, indicating the occurrence of metabolic disturbance. Among them, metabolic alteration of liver and intestine content was more significant. Based on the metabolic data of liver, 19 differential metabolites were discovered between DIO and control, 12 between DIO-CCl₄ and DIO, and 47 between DIO-CCl₄ and normal. These metabolites were mainly associated with aminoacyl-tRNA biosynthesis, nitrogen metabolism, lipid metabolism, glyoxylate and dicarboxylate metabolism, and amino metabolism. Further study revealed that the intervention of obeticholic acid (OCA) could partly reverse the damage of CCl₄. The correlation analysis of metabolite levels and clinical parameters showed that phosphatidylcholines were negatively associated with serum alanine aminotransferase, aspartate aminotransferase, NAFLD activity score, and fibrosis score, while lysophosphatidylcholines, sphingomyelins, amino acids, and acylcarnitines shared the reverse pattern. Our study investigated metabolic alteration among control, NAFLD model, and OCA treatment groups, providing preclinical information to understand the mechanism of NAFLD and amelioration of OCA.

Nonalcoholic Steatohepatitis and HCC in a Hyperphagic Mouse Accelerated by Western Diet

BACKGROUND & AIMS

How benign liver steatosis progresses to nonalcoholic steatohepatitis (NASH), fibrosis, and hepatocellular carcinoma (HCC) remains elusive. NASH progression entails diverse pathogenic mechanisms and relies on complex cross-talk between multiple tissues such as the gut, adipose tissues, liver, and the brain. Using a hyperphagic mouse fed with a Western diet (WD), we aimed to elucidate the cross-talk and kinetics of hepatic and extrahepatic alterations during NASH-HCC progression, as well as regression.

METHODS

Hyperphagic mice lacking a functional Alms1 gene (Foz/Foz) and wild-type littermates were fed WD or standard chow for 12 weeks for NASH/fibrosis and for 24 weeks for HCC development. NASH regression was modeled by switching back to normal chow after NASH development.

RESULTS

Foz+WD mice were steatotic within 1 to 2 weeks, developed NASH by 4 weeks, and grade 3 fibrosis by 12 weeks, accompanied by chronic kidney injury. Foz+WD mice that continued on WD progressed to cirrhosis and HCC within 24 weeks and had reduced survival as a result of cardiac dysfunction. However, NASH mice that were switched to normal chow showed NASH regression, improved survival, and did not develop HCC. Transcriptomic and histologic analyses of Foz/Foz NASH liver showed strong concordance with human NASH. NASH was preceded by an early disruption of gut barrier, microbial dysbiosis, lipopolysaccharide leakage, and intestinal inflammation. This led to acute-phase liver inflammation in Foz+WD mice, characterized by neutrophil infiltration and increased levels of several chemokines/cytokines. The liver cytokine/chemokine profile evolved as NASH progressed, with subsequent predominance by monocyte recruitment.

CONCLUSIONS

The Foz+WD model closely mimics the pathobiology and gene signature of human NASH with fibrosis and subsequent HCC. Foz+WD mice provide a robust and relevant preclinical model of NASH, NASH-associated HCC, chronic kidney injury, and heart failure.

Inhibition of miR-188-5p alleviates hepatic fibrosis by significantly reducing the activation and proliferation of HSCs through PTEN/PI3K/AKT pathway

Persistent hepatic damage and chronic inflammation in liver activate the quiescent hepatic stellate cells (HSCs) and cause hepatic fibrosis (HF). Several microRNAs regulate the activation and proliferation of HSCs, thereby playing a critical role in HF progression. Previous studies have reported that miR‐188‐5p is dysregulated during the process of HF. However, the role of miR‐188‐5p in HF remains unclear. This study investigated the potential role of miR‐188‐5p in HSCs and HF. Firstly, we validated the miR‐188‐5p expression in primary cells isolated from liver of carbon tetrachloride (CCl₄)‐induced mice, TGF‐β1‐induced LX‐2 cells, livers from 6‐month high‐fat diet (HFD)‐induced rat and 4‐month HFD‐induced mice NASH models, and human non‐alcoholic fatty liver disease (NAFLD) patients. Furthermore, we used miR‐188‐5p inhibitors to investigate the therapeutic effects of miR‐188‐5p inhibition in the HFD + CCl₄ induced in vivo model and the potential role of miR‐188‐5p in the activation and proliferation of HSCs. This present study reported that miR‐188‐5p expression is significantly increased in the human NAFLD, HSCs isolated from liver of CCl₄ induced mice, and in vitro and in vivo models of HF. Mimicking the miR‐188‐5p resulted in the up‐regulation of HSC activation and proliferation by directly targeting the phosphatase and tensin homolog (PTEN). Moreover, inhibition of miR‐188‐5p reduced the activation and proliferation markers of HSCs through PTEN/AKT pathway. Additionally, in vivo inhibition of miR‐188‐5p suppressed the HF parameters, pro‐fibrotic and pro‐inflammatory genes, and fibrosis. Collectively, our results uncover the pro‐fibrotic role of miR‐188‐5p. Furthermore, we demonstrated that miR‐188‐5p inhibition decreases the severity of HF by reducing the activation and proliferation of HSCs through PTEN/AKT pathway.

Use of a convolutional neural network and quantitative ultrasound for diagnosis of fatty liver

Quantitative ultrasound (QUS) was used to classify rabbits that were induced to have liver disease by placing them on a fatty diet for a defined duration and/or periodically injecting them with CCl₄. The ground truth of the liver state was based on lipid liver percents estimated via the Folch assay and hydroxyproline concentration to quantify fibrosis. Rabbits were scanned ultrasonically in vivo using a SonixOne scanner and an L9-4/38 linear array. Liver fat percentage was classified based on the ultrasonic backscattered radiofrequency (RF) signals from the livers using either QUS or a 1-D convolutional neural network (CNN). Use of QUS parameters with linear regression and canonical correlation analysis demonstrated that the QUS parameters could differentiate between livers with lipid levels above or below 5%. However, the QUS parameters were not sensitive to fibrosis. The CNN was implemented by analyzing raw RF ultrasound signals without using separate reference data. The CNN outputs the classification of liver as either above or below a threshold of 5% fat level in the liver. The CNN outperformed the classification utilizing the QUS parameters combined with a support vector machine in differentiating between low and high lipid liver levels (i.e., accuracies of 74% versus 59% on the testing data). Therefore, although the CNN did not provide a physical interpretation of the tissue properties (e.g., attenuation of the medium or scatterer properties) the CNN had much higher accuracy in predicting fatty liver state and did not require an external reference scan.

Impaired liver regeneration and lipid homeostasis in CCl4 treated WDR13 deficient mice

WDR13 - a WD repeat protein, is abundant in pancreas, liver, ovary and testis. Absence of this protein in mice has been seen to be associated with pancreatic β-cell proliferation, hyperinsulinemia and age dependent mild obesity. Previously, we have reported that the absence of WDR13 in diabetic Lepr^db/db mice helps in amelioration of fatty liver phenotype along with diabetes and systemic inflammation. This intrigued us to study direct liver injury and hepatic regeneration in Wdr13^−/0 mice using hepatotoxin CCl₄. In the present study we report slower hepatic regeneration in Wdr13^−/0 mice as compared to their wild type littermates after CCl₄ administration. Interestingly, during the regeneration phase, hepatic hypertriglyceridemia was observed in Wdr13^−/0 mice. Further analyses revealed an upregulation of PPAR pathway in the liver of CCl₄- administered Wdr13^−/0 mice, causing de novo lipogenesis. The slower hepatic regeneration observed in CCl₄ administered Wdr13^−/0 mice, may be linked to liver hypertriglyceridemia because of activation of PPAR pathway.

Dihydromyricetin ameliorates chronic liver injury by reducing pyroptosis

BACKGROUND

Chronic liver injury (CLI) is now a worldwide disease. However, there is no effective treatment. Pyroptosis plays an essential role in CLI. Dihydromyricetin (DHM) resists oxidation and protects the liver. We hypothesize that the beneficial effect of DHM on CLI is related to its effect on the expression of pyroptosis-related molecules. Therefore, we studied the influence of DHM on CLI and pyroptosis.

AIM

To study the role of pyroptosis in the pathogenesis of CLI and the therapeutic mechanism of DHM.

METHODS

Thirty-two mice were randomly divided into four groups: The control group was injected with olive oil, the carbon tetrachloride (CCl₄) group was injected with CCl₄, the vehicle group was injected with hydroxypropyl-β-cyclodextrin while injecting CCl₄ and the DHM group was injected with DHM while injecting CCl₄. After four weeks of treatment, liver tissues from the mice were stained with hematoxylin and eosin, and oil red O. Blood was collected from the angular vein for serological analysis. The severity of CLI was estimated. Some liver tissue was sampled for immunohistochemistry, Western blotting and quantitative reverse transcription PCR to observe the changes in pyroptosis-related molecules.

RESULTS

Serum total cholesterol, low density lipoprotein, aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in the CCl₄ group were higher than those in the control group, and serum total cholesterol, low density lipoprotein, AST and ALT in the DHM group were lower than those in the vehicle group. Hematoxylin and eosin and oil red O staining showed that there were more lipid droplets in the CCl₄ group than in the control group, and there were fewer lipid droplets in the DHM group than in the vehicle group. Western blotting showed that the expression of the pyroptosis-related molecules caspase-1, NOD-, LRR- and pyrin domain-containing 3 (NLRP3) and gasdermin D (GSDMD)-N in the CCl₄ group was higher than that in the control group, while expression of these proteins in the DHM group was lower than that in the vehicle group. Quantitative reverse transcription PCR results showed that the expression of the pyroptosis-related genes caspase-1, NLRP3, GSDMD and interleukin-1β (IL-1β) in the CCl₄ group was higher than that in the control group, while there was no significant change in NLRP3 and caspase-1 expression in the DHM group compared with that in the vehicle group, and the expression of GSDMD and IL-1β was decreased.

CONCLUSION

DHM improves CCl₄-induced CLI and regulates the pyroptosis pathway in hepatocytes. DHM may be a potential therapeutic agent for CLI.

Carbon tetrachloride (CCl4) accelerated development of non-alcoholic fatty liver disease (NAFLD)/steatohepatitis (NASH) in MS-NASH mice fed western diet supplemented with fructose (WDF)

BACKGROUND

Multiple murine models of nonalcoholic fatty liver disease/steatohepatitis (NAFLD/NASH) have been established by using obesogenic diets and/or chemical induction. MS-NASH mouse (formally FATZO) is a spontaneously developed dysmetabolic strain that can progress from hepatosteatosis to moderate fibrosis when fed a western diet supplemented with 5% fructose (WDF). This study aimed to use carbon tetrachloride (CCl4) to accelerate and aggravate progression of NAFLD/NASH in MS-NASH mouse.

METHODS

Male MS-NASH mice at 8 weeks of age were fed WDF for the entire study. Starting at 16 weeks of age, CCl4 was intraperitoneally administered twice weekly at a dose of 0.2 mL/kg for 3 weeks or 0.08 mL/kg for 8 weeks. Obeticholic acid (OCA, 30 mg/kg, QD) was administered in both MS-NASH and C57Bl/6 mice fed WDF and treated with CCl4 (0.08 mL/kg).

RESULTS

WDF enhanced obesity and hepatosteatosis, as well as induced moderate fibrosis in MS-NASH mice similar to previous reports. Administration of CCl4 accelerated liver fibrosis with increased bridging and liver hydroxyproline contents, but had no significant impact on liver steatosis and lipid contents. High dose CCl4 caused high mortality and dramatic elevation of ALT and ASL, while low dose CCl4 resulted in a moderate elevation of ALT and AST with low mortality. Compared to C57BI/6 mice with WDF and CCl4 (0.08 mL/kg), MS-NASH mice had more prominent hepatosteatosis and fibrosis. OCA treatment significantly lowered liver triglycerides, steatosis and fibrosis in both MS-NASH and C57Bl/6 mice fed WDF with CCl4 treatment.

CONCLUSIONS

CCl4 reduced induction time and exacerbated liver fibrosis in MS-NASH mice on WDF, proving a superior NASH model with more prominent liver pathology, which has been used favorably in pharmaceutical industry for testing novel NASH therapeutics.

Discovery and Optimization of Non-bile Acid FXR Agonists as Preclinical Candidates for the Treatment of Nonalcoholic Steatohepatitis

Farnesoid X receptor (FXR) plays a key role in bile acid homeostasis, inflammation, fibrosis, and metabolism of lipid and glucose and becomes a promising therapeutic target for nonalcoholic steatohepatitis (NASH) or other FXR-dependent diseases. The phase III trial results of obeticholic acid demonstrate that the FXR agonists emerge as a promising intervention in patients with NASH and fibrosis, but this bile acid-derived FXR agonist brings severe pruritus and an elevated risk of cardiovascular disease for patients. Herein, we reported our efforts in the discovery of a series of non-bile acid FXR agonists, and 36 compounds were designed and synthesized based on the structure-based drug design and structural optimization strategies. Particularly, compound 42 is a highly potent and selective FXR agonist, along with good pharmacokinetic profiles, high liver distribution, and preferable in vivo efficacy, indicating that it is a potential candidate for the treatment of NASH or other FXR-dependent diseases.

Animal models for liver disease - A practical approach for translational research

Animal models are crucial for improving our understanding of human pathogenesis, enabling researchers to identify therapeutic targets and test novel drugs. In the current review, we provide a comprehensive summary of the most widely used experimental models of chronic liver disease, starting from early stages of fatty liver disease (non-alcoholic and alcoholic) to steatohepatitis, advanced cirrhosis and end-stage primary liver cancer. We focus on aspects such as reproducibility and practicality, discussing the advantages and weaknesses of available models for researchers who are planning to perform animal studies in the near future. Additionally, we summarise current and prospective models based on human tissue bioengineering.

Targeted Nutrient Modifications in Purified Diets Differentially Affect Nonalcoholic Fatty Liver Disease and Metabolic Disease Development in Rodent Models

Nonalcoholic fatty liver disease (NAFLD) is a complex spectrum of disorders ranging from simple benign steatosis to more aggressive forms of nonalcoholic steatohepatitis (NASH) and fibrosis. Although not every patient with NAFLD/NASH develops liver complications, if left untreated it may eventually lead to cirrhosis and hepatocellular carcinoma. Purified diets formulated with specific nutritional components can drive the entire spectrum of NAFLD in rodent models. Although they may not perfectly replicate the clinical and histological features of human NAFLD, they provide a model to gain further understanding of disease progression in humans. Owing to the growing demand of diets for NAFLD research, and for our further understanding of how manipulation of dietary components can alter disease development, we outlined several commonly used dietary approaches for rodent models, including mice, rats, and hamsters, time frames required for disease development and whether other metabolic diseases commonly associated with NAFLD in humans occur.

High-trans fatty acid and high-sugar diets can cause mice with non-alcoholic steatohepatitis with liver fibrosis and potential pathogenesis

Background and aims

Even Non-alcoholic steatohepatitis (NASH) has been becoming the key role in process of liver fibrosis or cirrhosis, no any NASH involving liver fibrosis mice model which consistent with the mechanisms of fatty acid and glucose metabolism disorder was widely accepted. Here, we established a mouse model of nonalcoholic steatohepatitis (NASH) with liver fibrosis using a high-fat, high-carbohydrate diet (HFHC) and analyzed the potential pathogenesis using a transcriptome microarray.

Methods

Fifty mice were stratified by weight and randomly divided into the HFHC model and control (Con) groups. Ten mice were sacrificed at the beginning of the experiments, 10 mice of HFHC and Con group were euthanized at the end of 20 and 30 weeks. The following analyses were performed: biochemical analysis; histological assessment; evaluation of hepatic type I collagen (Col-I), α-smooth muscle actin (α-SMA) and transforming growth factor-β1 (TGF-β1) protein and mRNA expression levels; and transcriptomic gene chip analysis.

Results

Compared with the Con group at each time point, the body weight and liver wet weight of the HFHC model group of mice were significantly higher. At 30th weeks, alanine aminotransferase (ALT), aspartate aminotransferase (AST), fasting blood glucose (FBG) and fasting insulin (FINS) levels or activities and the triglyceride (TG) and hydroxyproline (HYP) content in the HFHC model group were significantly elevated. Severe steatosis was present in the liver tissues contributed from the HFHC group of mice. Typically, substantial perisinusoidal fibrosis with a cage-like structure and bridging formations were observed in the mice liver in HFHC group. Col-I, α-SMA and TGF-β1 protein and mRNA expression levels in liver tissues of HFHC mice dramatically increased over time. Compared with the Con group, the HFHC group had 151 differentially expressed genes that were involved in 41 signaling pathways.

Conclusions

After keeping 30 weeks HFHC diet treatment, the mice exhibited substantial liver fibrosis, hepatic steatosis, ballooning degeneration and inflammation. Basing on the transcriptome microarray assays, the experimental NASH involving liver fibrosis potentially related to dramatically changed ECM-receptor interaction, Toll-like receptor signaling and other signaling pathways.

Dysregulation of bile acids increases the risk for preterm birth in pregnant women

Preterm birth (PTB) is the leading cause of perinatal mortality and newborn complications. Bile acids are recognized as signaling molecules regulating a myriad of cellular and metabolic activities but have not been etiologically linked to PTB. In this study, a hospital-based cohort study with 36,755 pregnant women is conducted. We find that serum total bile acid levels directly correlate with the PTB rates regardless of the characteristics of the subjects and etiologies of liver disorders. Consistent with the findings from pregnant women, PTB is successfully reproduced in mice with liver injuries and dysregulated bile acids. More importantly, bile acids dose-dependently induce PTB with minimal hepatotoxicity. Furthermore, restoring bile acid homeostasis by farnesoid X receptor activation markedly reduces PTB and dramatically improves newborn survival rates. The findings thus establish an etiologic link between bile acids and PTB, and open an avenue for developing etiology-based therapies to prevent or delay PTB.

Isorhamnetin Alleviates Steatosis and Fibrosis in Mice with Nonalcoholic Steatohepatitis

Nonalcoholic steatohepatitis (NASH) is the most severe and progressive form of nonalcoholic fatty liver disease (NAFLD), which can lead to life-threatening conditions, however, there is still no approved drug for the treatment of NASH. In this study we used human-like NASH mouse model and treated orally with isorhamnetin at a dose of 50 mg/kg to analyze the effect of isorhamnetin on the progression of NASH. NASH-induced mice represented severe steatosis with inflammation, and fibrosis in liver accompanied with high level of liver injury markers in serum. Isorhamnetin treatment reduced intrahepatic lipid accumulation and TG content by inhibiting de novo lipogenic pathway in NASH-induced mice. Consistent with this, isorhamnetin-treated NASH mice showed improved liver injury markers, reduced collagen deposition as well as decreased gene expression of fibrogenic markers. Taken together, here we showed for the first time that synthesized isorhamnetin alleviates pathologic features of NASH and thus can potentially contribute to NASH drug development.

New Rat Model of Advanced NASH Mimicking Pathophysiological Features and Transcriptomic Signature of The Human Disease

Non-alcoholic steatohepatitis (NASH) is a major cause of chronic liver disease. However, most available animal models fail to reflect the whole spectrum of the disease. Liver fibrosis and portal hypertension are the strongest prognostic markers in advanced NASH. We herein aimed at developing a new model of NASH in male rats, obtained using a multi-hit protocol that combines the administration of a high fat and high-cholesterol diet with CCl4 and phenobarbital. Following this protocol, rats showed the full characteristics of advanced human NASH after 10 weeks and NASH with cirrhosis by 24 weeks. Specifically, our NASH rats exhibited: steatosis and metabolic syndrome, lipotoxicity, hepatocellular ballooning necrosis, inflammation and importantly, marked hepatic fibrosis and significant portal hypertension. Furthermore, a whole transcriptomic analysis of liver tissue from our rat model using next generation sequencing was compared with human NASH and illustrated the similarity of this pre-clinical model with the human disease. Pathway enrichment analysis showed that NASH animals shared a relevant number of central pathways involved in NASH pathophysiology, such as those related with cell death, as well as inflammatory or matrix remodeling. The present study defines a pre-clinical model of moderate and advanced NASH that mimics the human disease, including pathophysiologic characteristics and transcriptomic signature.

Rapeseed Protein-Derived Antioxidant Peptide RAP Ameliorates Nonalcoholic Steatohepatitis and Related Metabolic Disorders in Mice

Rapeseed protein hydrolysates have recently shown in vitro antioxidant and anti-inflammatory activities. However, scant data exist about their in vivo activities. Here, we report that the peptide DHNNPQIR (hereinafter referred to as RAP-8), a bioactive peptide originated from rapeseed protein, exhibits excellent in vivo efficacy in mouse models of nonalcoholic steatohepatitis (NASH) and hepatic fibrosis. We demonstrated that RAP-8 significantly reduced hepatic steatosis and improved insulin resistance and lipid metabolism. Furthermore, RAP-8 showed markedly reduced hepatic inflammation, fibrosis, liver injury, and metabolic deterioration. In particular, RAP-8 directly suppressed fibrosis-associated gene expression, including α-smooth muscle actin (α-Sma) and collagen type I (Col-1α) in the liver of mice in vivo. In addtion, RAP-8 significantly decreased macrophage infiltration and reduced pro-inflammatory cytokines secretion. Finally, we found that RAP-8 administration significantly decreased oxidative stress-induced apoptosis in liver injury induced by CCl₄. Therefore, our results suggest that RAP-8 could be available for treatment of NASH and NASH-related metabolic disorders as a potential therapeutic candidate.

l-Carnitine-induced amelioration of HFD-induced hepatic dysfunction is accompanied by a reduction in hepatic TNF-α and TGF-β1

In this study, we evaluated the possible mechanisms through which l-carnitine ameliorates the adverse effects from obesity in rats, induced with a high-fat diet (HFD). For this, 56 albino Wister rats were randomly assigned to 7 groups. The control group was fed a basal diet and injected with saline. The second group was fed the basal diet and injected with l-carnitine (200 mg/kg body mass, by intraperitoneal injection; i.p.). The third group were fed the HFD. The fourth group was fed the HFD and injected with l-carnitine (200 mg/kg body mass, i.p.) for 8 weeks. The fifth group was fed the HFD for 10 weeks. The sixth group were fed the HFD for 10 weeks and were also injected with l-carnitine (200 mg/kg body mass, i.p.) during the final 2 weeks. The seventh group was fed the HFD diet for 8 weeks then the basal diet for 2 weeks. The HFD induced significantly increased levels of hyperglycemia, lipid peroxidation, pathological changes, TNF-α and TGF-β1 protein expression in hepatic tissue, food intake, body weight gain, serum levels of total and non-high-density lipoprotein cholesterol, ketone bodies, triacylglycerol, urea, creatinine, AST, and ALT. However, the HFD diet significantly decreased serum levels of high-density lipoprotein (HDL) and hepatic levels of reduced glutathione. l-Carnitine ameliorated the effects of the HFD on the above-mentioned parameters. This study indicated that l-carnitine had protective and curative effects against HFD-induced hepatosteatosis by reducing hepatic oxidative stress and protein expression of TNF-α and TGF-β1.

Inhibition of Plasminogen Activator Inhibitor 1 Attenuates Hepatic Steatosis but Does Not Prevent Progressive Nonalcoholic Steatohepatitis in Mice

Plasminogen activator inhibitor 1 (PAI‐1), an essential regulator of fibrinolysis, is increasingly implicated in the pathogenesis of metabolic disorders, such as obesity and nonalcoholic fatty liver disease (NAFLD). Pharmacologic inhibition of PAI‐1 is emerging as a highly promising therapeutic strategy for obesity and its sequelae. Given the well‐established profibrotic function of PAI‐1, we considered whether PAI‐1 may serve as a target for antifibrotic therapy in nonalcoholic steatohepatitis (NASH). We therefore determined the effect of genetic Pai‐1 deletion and pharmacologic PAI‐1 inhibition on the development of NASH‐related fibrosis in mice. Pai‐1 knockout (Pai‐1^–/–) and wild‐type control (Pai‐1^+/+) mice were fed a high‐fat/high‐cholesterol high‐sugar (HFHS) diet or a methionine‐ and choline‐deficient (MCD) diet to induce steatohepatitis with fibrosis. PAI‐1 was pharmacologically inhibited using the small molecule inhibitor TM5441 in wild‐type C57BL/6 mice fed an HFHS or MCD diet. Either genetic deletion of Pai‐1 or pharmacologic inhibition of PAI‐1 attenuated MCD diet‐induced hepatic steatosis but did not prevent hepatic inflammation or fibrosis. Targeted inhibition of PAI‐1 conferred transient protection from HFHS diet‐induced obesity and hepatic steatosis, an effect that was lost with prolonged exposure to the obesigenic diet. Neither genetic deletion of Pai‐1 nor pharmacologic inhibition of PAI‐1 prevented HFHS diet‐induced hepatic inflammation or fibrosis. Conclusion:Pai‐1 regulates hepatic lipid accumulation but does not promote NASH progression. The PAI‐1 inhibitor TM5441 effectively attenuates diet‐induced obesity and hepatic steatosis but does not prevent NASH‐related fibrosis in mice.