Murine Model Of Nonalcoholic Steatohepatitis Research Articles

Kaempferol Alleviates Hepatic Injury in Nonalcoholic Steatohepatitis (NASH) by Suppressing Neutrophil-Mediated NLRP3-ASC/TMS1-Caspase 3 Signaling.

Non-alcoholic fatty liver disease (NAFLD) is a significant hepatic condition that has gained worldwide attention. Kaempferol (Kae), renowned for its diverse biological activities, including anti-inflammatory, antioxidant, anti-aging, and cardio-protective properties, has emerged as a potential therapeutic candidate for non-alcoholic steatohepatitis (NASH). Despite its promising therapeutic potential, the precise underlying mechanism of Kae's beneficial effects in NASH remains unclear. Therefore, this study aims to clarify the mechanism by conducting comprehensive in vivo and in vitro experiments. In this study, a murine model of non-alcoholic steatohepatitis (NASH) was established by feeding C57BL/6 female mice a high-fat diet for 12 weeks. Kaempferol (Kae) was investigated for its ability to modulate systemic inflammatory responses and lipid metabolism in this model (20 mg/kg per day). Notably, Kae significantly reduced the expression of NLRP3-ASC/TMS1-Caspase 3, a crucial mediator of liver tissue inflammation. Additionally, in a HepG2 cell model induced with palmitic acid/oleic acid (PA/OA) to mimic NASH conditions, Kae demonstrated the capacity to decrease lipid droplet accumulation and downregulate the expression of NLRP3-ASC/TMS1-Caspase 3 (20 µM and the final concentration to 20 nM). These findings suggest that Kae may hold therapeutic potential in the treatment of NASH by targeting inflammatory and metabolic pathways. These findings suggest that kaempferol holds potential as a promising therapeutic intervention for ameliorating non-alcoholic fatty liver disease (NAFLD).

Efficacy and mechanism of action of Yanxiao Di'naer formula for non-alcoholic steatohepatitis treatment based on metabolomics and RNA sequencing

Ethnopharmacological relevanceNonalcoholic fatty liver disease (NAFLD) is the most prevalent chronic liver disease worldwide. Nonalcoholic steatohepatitis (NASH) is a crucial component of this disease spectrum. The Yanxiao Di'naer formula (YXDNE) is an Uyghur medical extract that has been used in folk medicine to treat hepatitis for a long time. However, the role and mechanism of action of YXDNE in NASH treatment remains unclear. ObjectiveThe objective of this study was to assess the effectiveness of YXDNE in treating NASH induced by injections of carbon tetrachloride combined with a high-fat high-cholesterol diet (HFHCD), and to clarify the underlying mechanisms. MethodsThe compounds in the YXDNE extract were analysed for classification and proportions using ultra-performance liquid chromatography-mass spectrometry. The efficacy of YXDNE in treating abnormal lipid metabolism was evaluated in L02 cells in vitro. In addition, a C57BL/6 mouse model of NASH was established to evaluate the therapeutic efficacy of YXDNE in vivo. Metabolomics and RNA sequencing were used to analyse the therapeutic effects of YXDNE on the liver. The corresponding signalling pathways were found to target AMPKα1, PPARα, and NF-κB. The efficacy of YXDNE was validated using inhibitors or silencing RNA (siRNA) against AMPKα1 and PPARα. ResultsThis study confirmed that YXDNE treatment ameliorated NASH in a murine model of this disease. Metabolomics analysis suggested that YXDNE efficacy was associated with fatty acid catabolism and AMPK signalling pathways. RNA sequencing results showed that YXDNE efficacy in treating NASH was highly correlated with the AMPK, PPARα and NF-κB pathways. Both in vitro and in vivo experimental data demonstrated that YXDNE affected the expression of p-AMPKα1, PPARα, p–NF–κB, IκB, and p-IκB. The efficacy of YXDNE in treating NASH in vitro was cancelled when AMPK was inhibited with Compound C or PPARα was modulated via siRNA. ConclusionsYXDNE may have a therapeutic effect on abnormal lipid metabolism in L02 cells and in a murine model of NASH by affecting the AMPKα1/PPARα/NF-κB signalling pathway. Therefore, YXDNE has the potential for clinical application in the prevention and treatment of NASH.

Cenicriviroc Suppresses and Reverses Steatohepatitis by Regulating Macrophage Infiltration and M2 Polarization in Mice.

The inhibition of hepatic macrophage and Kupfer cell recruitment and activation is a potential strategy for treating insulin resistance and nonalcoholic steatohepatitis (NASH). Cenicriviroc (CVC), a dual C-C chemokine receptor 2 (CCR2) and CCR5 antagonist, has shown antifibrotic activity in murine models of NASH and has been evaluated in clinical trials on patients with NASH. This study investigated the effects of CVC on macrophage infiltration and polarization in a lipotoxic model of NASH. C57BL/6 mice were fed a high-cholesterol, high-fat (CL) diet or a CL diet containing 0.015% CVC (CL + CVC) for 12 weeks. Macrophage recruitment and activation were assayed by immunohistochemistry and flow cytometry. CVC supplementation attenuated excessive hepatic lipid accumulation and peroxidation and alleviated glucose intolerance and hyperinsulinemia in the mice that were fed the CL diet. Flow cytometry analysis revealed that compared with the CL group, mice fed the CL + CVC diet had fewer M1-like macrophages, more M2-like macrophages, and fewer T cell counts, indicating that CVC caused an M2-dominant shift of macrophages in the liver. Similarly, CVC decreased lipopolysaccharide-stimulated M1-like macrophage activation, whereas it increased interleukin-4-induced M2-type macrophage polarization in vitro. In addition, CVC attenuated hepatic fibrosis by repressing hepatic stellate cell activation. Lastly, CVC reversed insulin resistance as well as steatosis, inflammation, and fibrosis of the liver in mice with pre-existing NASH. In conclusion, CVC prevented and reversed hepatic steatosis, insulin resistance, inflammation, and fibrogenesis in the liver of NASH mice via M2 macrophage polarization.

Utility of pemafibrate in nonalcoholic steatohepatitis model mice induced by a choline-deficient, high-fat diet and dextran sulfate sodium

AimThe purpose of this study was to examine the effect of pemafibrate in a murine model of non-alcoholic steatohepatitis (NASH). MethodsForty-two, 19-week-old, male, C57BL/6J mice were divided into three groups: a Control group (n = 14), a dextran sulfate sodium (DSS) group (n = 14), and a DSS + PEM group (n = 14). All mice were given a standard rodent diet for the first week, followed by a choline-deficient, high-fat diet (CDHF) for the next 12 weeks. The 22nd day after the animals arrived was taken as Day 1 of the experiment. The Control group continued the CDHF diet and MilliQ water. The DSS group continued the CDHF diet, but starting on Day 1, the group received 0.8 % DSS to drink for 7 consecutive days, followed by MilliQ water for 10 days; this was taken as one course, and it was repeated on the same schedule until autopsy. The DSS + PEM group received the CDHF diet with PEM 0.1 mg/kg/day. Their drinking water was the same as that of the DSS group. On Seven animals from each group were autopsied on each of Day 50 and Day 120, and histopathological and immunohistochemical examinations, as well as quantitative RNA and cytokine measurements, of autopsied mice were performed. ResultsPemafibrate improved hepatic steatosis (decreased steatosis area), improved liver inflammation enhanced by DSS (decreased aspartate transaminase and alanine aminotransferase), improved hepatic fibrosis promoted by DSS (decreased fibrotic areas and a marker of fibrosis), inhibited tumorigenesis, and decreased intestinal inflammation in the NASH model mice. ConclusionsIn a murine model of NASH, mixing PEM 0.1 mg/kg/day into the diet inhibited disease progression and tumor formation.

SLC7A11-ROS/αKG-AMPK axis regulates liver inflammation through mitophagy and impairs liver fibrosis and NASH progression

The changes of inflammation and metabolism are two features in nonalcoholic steatohepatitis (NASH). However, how they interact to regulate NASH progression remains largely unknown. Our works have demonstrated the importance of solute carrier family 7 member 11 (SLC7A11) in inflammation and metabolism. Nevertheless, whether SLC7A11 regulates NASH progression through mediating inflammation and metabolism is unclear. In this study, we found that SLC7A11 expression was increased in liver samples from patients with NASH. Upregulated SLC7A11 level was also detected in two murine NASH models. Functional studies showed that SLC7A11 knockdown or knockout had augmented steatohepatitis with suppression of inflammatory markers in mice. However, overexpression of SLC7A11 dramatically alleviated diet-induced NASH pathogenesis. Mechanically, SLC7A11 decreased reactive oxygen species (ROS) level and promoted α-ketoglutarate (αKG)/prolyl hydroxylase (PHD) activity, which activated AMPK pathway. Furthermore, SLC7A11 impaired expression of NLRP3 inflammasome components through AMPK-mitophagy axis. IL-1β release through NLRP3 inflammasome recruited myeloid cells and promoted hepatic stellate cells (HSCs) activation, which contributed to the progression of liver injury and fibrosis. Anti-IL-1β and anakinra might attenuate the hepatic inflammatory response evoked by SLC7A11 knockdown. Moreover, the upregulation of SLC7A11 in NASH was contributed by lipid overload-induced JNK-c-Jun pathway. In conclusions, SLC7A11 acts as a protective factor in controlling the development of NASH. Upregulation of SLC7A11 is protective by regulating oxidation, αKG and energy metabolism, decreasing inflammation and fibrosis.

Macrophage RAGE activation is proinflammatory in NASH.

Intrahepatic macrophages in nonalcoholic steatohepatitis (NASH) are heterogenous and include proinflammatory recruited monocyte-derived macrophages. The receptor for advanced glycation endproducts (RAGE) is expressed on macrophages and can be activated by damage associated molecular patterns (DAMPs) upregulated in NASH, yet the role of macrophage-specific RAGE signaling in NASH is unclear. Therefore, we hypothesized that RAGE-expressing macrophages are proinflammatory and mediate liver inflammation in NASH. Compared with healthy controls, RAGE expression was increased in liver biopsies from patients with NASH. In a high-fat, -fructose, and -cholesterol-induced (FFC)-induced murine model of NASH, RAGE expression was increased, specifically on recruited macrophages. FFC mice that received a pharmacological inhibitor of RAGE (TTP488), and myeloid-specific RAGE KO mice (RAGE-MKO) had attenuated liver injury associated with a reduced accumulation of RAGE+ recruited macrophages. Transcriptomics analysis suggested that pathways of macrophage and T cell activation were upregulated by FFC diet, inhibited by TTP488 treatment, and reduced in RAGE-MKO mice. Correspondingly, the secretome of ligand-stimulated BM-derived macrophages from RAGE-MKO mice had an attenuated capacity to activate CD8+ T cells. Our data implicate RAGE as what we propose to be a novel and potentially targetable mediator of the proinflammatory signaling of recruited macrophages in NASH.

Time-restricted feeding has a limited effect on hepatic lipid accumulation, inflammation and fibrosis in a choline-deficient high-fat diet-induced murine NASH model.

Nonalcoholic steatohepatitis (NASH) occurs worldwide and is characterized by lipid accumulation in hepatocytes, hepatic inflammation, fibrosis, and an increased risk of cirrhosis. Although a major proportion of NASH patients exhibit obesity and insulin resistance, 20% lack a high body mass and are categorized as "non-obese NASH". Time-restricted feeding (TRF), limiting daily food intake within certain hours, improves obesity, lipid metabolism, and liver inflammation. Here, we determined whether TRF affects NASH pathology induced by a choline-deficient high-fat diet (CDAHFD), which does not involve obesity. TRF ameliorated the increase in epididymal white adipose tissue and plasma alanine transaminase and aspartate transaminase levels after 8 weeks of a CDAHFD. Although gene expression of TNF alpha in the liver was suppressed by TRF, it did not exhibit a suppressive effect on hepatic lipid accumulation, gene expression of cytokines and macrophage markers (Mcp1, IL1b, F4/80), or fibrosis, as evaluated by Sirius red staining and western blot analysis of alpha-smooth muscle actin. A CDAHFD-induced increase in gene expression related to fibrogenesis (Collagen 1a1 and TGFβ) was neither suppressed by TRF nor that of alpha-smooth muscle actin but was increased by TRF. Our results indicated that TRF has a limited suppressive effect on CDAHFD-induced NASH pathology.

Chronic kidney disease in a murine model of non-alcoholic steatohepatitis (NASH)

Clinical studies suggest that non-alcoholic steatohepatitis (NASH) is an independent risk factor for chronic kidney disease (CKD), but causality and mechanisms linking these two major diseases are lacking. To assess whether NASH can induce CKD, we have characterized kidney function, histological features, transcriptomic and lipidomic profiles in a well-validated murine NASH model. Mice with NASH progressively developed significant podocyte foot process effacement, proteinuria, glomerulosclerosis, tubular epithelial cell injury, lipid accumulation, and interstitial fibrosis. The progression of kidney fibrosis paralleled the severity of the histologic NASH-activity score. Significantly, we confirmed the causal link between NASH and CKD by orthotopic liver transplantation, which attenuated proteinuria, kidney dysfunction, and fibrosis compared with control sham operated mice. Transcriptomic analysis of mouse kidney cortices revealed differentially expressed genes that were highly enriched in mitochondrial dysfunction, lipid metabolic process, and insulin signaling pathways in NASH-induced CKD. Lipidomic analysis of kidney cortices further revealed that phospholipids and sphingolipids were the most significantly changed lipid species. Notably, we found similar kidney histological changes in human NASH and CKD. Thus, our results confirm a causative role of NASH in the development of CKD, reveal potential pathophysiologic mechanisms of NASH-induced kidney injury, and established a valuable model to study the pathogenesis of NASH-associated CKD. This is an important feature of fatty liver disease that has been largely overlooked but has clinical and prognostic importance.

Indole-3-carbinol and chlorogenic acid combination modulates gut microbiome and attenuates nonalcoholic steatohepatitis in a murine model

Nonalcoholic fatty liver disease (NAFLD) is the most common chronic liver disease worldwide, affecting almost 32% of the population and ranging from simple steatosis to nonalcoholic steatohepatitis (NASH). Recent findings indicate that the fast-growing prevalence of NAFLD might be linked to adherence to a Westernized diet (WD), mostly composed of fat/sugar-enriched foods. The WD has been reportedly targeted as a potential driver of gut-liver axis unbalance, suggesting a major role in NASH. On the other hand, bioactive food compounds feature as a potential chemopreventive strategy against NASH, due to their beneficial effects (i.e, anti-inflammatory/oxidant activity and modulation of gut microbiome). Brassicaceae vegetables are known for their high amount of isothiocyanates and polyphenols, as indole-3-carbinol (I3C) and chlorogenic acid (CGA). Thus, we sought to assess the effects of human relevant doses of I3C and CGA isolated or in combination (5/125 mg/Kg of body weight, respectively) on a diet/chemical-induced murine model of NASH. I3C + CGA oral treatment diminished NAFLD activity score (NAS) (p < 0.0001), as well as alleviated the hepatic lipid (p = 0.0011) accumulation, prevented hepatic stellate cell (HSC) activation (p < 0.0001), and subsequent fibrosis (p < 0.0001). The combination also reduced the number of both hepatic CD68-positive macrophages (p < 0.0001) and cleaved caspase-3 hepatocytes (p < 0.0001) and diminished the malondialdehyde levels (p = 0.0155). Additionally, the combination of I3C + CGA restored the relative abundance of Alistipes (p = 0.0299), Allobaculum (p = 0.0014), Bacteroides (p = 0.0046), and Odoribacter (p = 0.0030) bacteria genera on the gut microbiome. Taken together, these findings show that the combination of I3C + CGA at populational-relevant ingestion, rather than the I3C or CGA alone, was able to modulate gut microbiome and attenuate NASH in this hybrid model mouse.

Lysosomal cholesterol overload in macrophages promotes liver fibrosis in a mouse model of NASH.

Accumulation of lipotoxic lipids, such as free cholesterol, induces hepatocyte death and subsequent inflammation and fibrosis in the pathogenesis of nonalcoholic steatohepatitis (NASH). However, the underlying mechanisms remain unclear. We have previously reported that hepatocyte death locally induces phenotypic changes in the macrophages surrounding the corpse and remnant lipids, thereby promoting liver fibrosis in a murine model of NASH. Here, we demonstrated that lysosomal cholesterol overload triggers lysosomal dysfunction and profibrotic activation of macrophages during the development of NASH. β-cyclodextrin polyrotaxane (βCD-PRX), a unique supramolecule, is designed to elicit free cholesterol from lysosomes. Treatment with βCD-PRX ameliorated cholesterol accumulation and profibrotic activation of macrophages surrounding dead hepatocytes with cholesterol crystals, thereby suppressing liver fibrosis in a NASH model, without affecting the hepatic cholesterol levels. In vitro experiments revealed that cholesterol-induced lysosomal stress triggered profibrotic activation in macrophages predisposed to the steatotic microenvironment. This study provides evidence that dysregulated cholesterol metabolism in macrophages would be a novel mechanism of NASH.

Human liver stem cell-derived extracellular vesicles modulate long non-coding RNA expression profile in an in vivo model of non-alcoholic steatohepatitis

Aim: Modifications in long non-coding RNA (lncRNA) expression are associated with inflammation and fibrosis in chronic liver diseases. It has been recently demonstrated that human liver stem cells (HLSCs) and their extracellular vesicles (EVs) can effectively reduce inflammation and fibrosis in a murine model of non-alcoholic steatohepatitis (NASH). Now it has been evaluated whether EVs can modify the expression of inflammation-related lncRNAs in NASH liver. Methods: To induce NASH, severe combined immunodeficient mice were fed with a methionine-choline-deficient diet for 4 weeks. After 2 weeks of diet, 2.5 × 109 EVs were intravenously injected twice a week. An array of 84 inflammation-related lncRNAs was performed on the RNA isolated from NASH livers, and the expression of 14 selected lncRNAs was then validated by real-time polymerase chain reaction (PCR) analysis. Expression levels of maternally expressed gene 3 (Meg3) were further evaluated in vitro, in an activated human hepatic immortalized stellate cell line (LX-2) stimulated with EVs. Results: The screening showed an altered lncRNA expression profile in the liver of NASH mice, in respect to control healthy mice. EV treatment modulated several inflammation-related lncRNAs in NASH livers. Real-time PCR validation of array results indicated that EVs restored to normal levels the expression of 10 lncRNAs altered in NASH. In particular, EV stimulation reduced Meg3 expression levels, which were increased in NASH as well as in activated LX-2. Conclusions: HLSC-EVs regulate the expression of inflammation-related lncRNAs impaired in NASH livers and in an in vitro model of liver fibrosis.

Nanoparticle-Mediated RNA Therapy Attenuates Nonalcoholic Steatohepatitis and Related Fibrosis by Targeting Activated Hepatic Stellate Cells.

Chronic liver injury and inflammation triggered by metabolic abnormalities initiate the activation of hepatic stellate cells (HSCs), driving fibrosis and parenchymal dysfunction, culminating in disorders such as nonalcoholic steatohepatitis (NASH). Unfortunately, there are currently no approved drugs capable of effectively treating NASH due to the challenges in addressing fibrosis and restoring extracellular matrix (ECM) homeostasis. We discovered a significant up-regulation of interleukin-11 (IL-11) in fibrotic livers using two well-established murine models of NASH. To leverage this signaling pathway, we developed a nanoparticle (NP)-assisted RNA interfering approach that specifically targets activated HSCs (aHSCs), blocking IL-11/ERK signaling to regulate HSC transdifferentiation along with fibrotic remodeling. The most potent NP, designated NP-AEAA, showed enhanced accumulation in fibrotic livers with NASH and was primarily enriched in aHSCs. We further investigated the therapeutic efficacy of aHSC-targeting NP-AEAA encapsulating small interfering RNA (siRNA) against IL11 or its cognate receptor IL11ra1 (termed siIL11@NP-AEAA or siIL11ra1@NP-AEAA, respectively) for resolving fibrosis and NASH. Our results demonstrate that both siIL11@NP-AEAA and siIL11ra1@NP-AEAA effectively inhibit HSC activation and resolve fibrosis and inflammation in two well-established murine models of NASH. Notably, siIL11ra1@NP-AEAA exhibits a superior therapeutic effect over siIL11@NP-AEAA, in terms of reducing liver steatosis and fibrosis as well as recovering liver function. These results constitute a targeted nanoparticulate siRNA therapeutic approach against the IL-11 signaling pathway of aHSCs in the fibrotic liver, offering a promising therapeutic intervention for NASH and other diseases.

Targeting Extracellular RNA Mitigates Hepatic Lipotoxicity and Liver Injury in NASH.

Non-alcoholic steatohepatitis (NASH) is a clinically serious stage of non-alcoholic fatty liver disease (NAFLD). Histologically characterized by hepatocyte ballooning, immune cell infiltration, and fibrosis, NASH, at a molecular level, involves lipid-induced hepatocyte death and cytokine production. Currently, there are very few diagnostic biomarkers available to screen for NASH, and no pharmacological intervention is available for its treatment. In this study, we show that hepatocyte damage induced by lipotoxicity results in the release of extracellular RNAs (eRNAs), which serve as damage-associated molecular patterns (DAMPs) that stimulate the expression of pro-apoptotic and pro-inflammatory cytokines, aggravate inflammation, and lead to cell death in HepG2 cells. Furthermore, the inhibition of eRNA activity by RNase 1 significantly increases cellular viability and reduces NF-kB-mediated cytokine production. Similarly, RNase 1 administration significantly improves hepatic steatosis, inflammatory and injury markers in a murine NASH model. Therefore, this study, for the first time, underscores the therapeutic potential of inhibiting eRNA action as a novel strategy for NASH treatment.

Therapeutic targeting of adipose tissue macrophages ameliorates liver fibrosis in non-alcoholic fatty liver disease

Background & Aims: The accumulation of adipose tissue macrophages (ATMs) in obesity has been associated with hepatic injury. However, the contribution of ATMs to hepatic fibrosis in non-alcoholic fatty liver disease (NAFLD) remains to be elucidated. Herein, we investigate the relationship between ATMs and liver fibrosis in patients with patients with NAFLD and evaluate the impact of modulation of ATMs over hepatic fibrosis in an experimental non-alcoholic steatohepatitis (NASH) model. MethodsAdipose tissue and liver biopsies from 42 patients with NAFLD with different fibrosis stages were collected. ATMs were characterised by immunohistochemistry and flow cytometry and the correlation between ATMs and liver fibrosis stages was assessed. Selective modulation of the ATM phenotype was achieved by i.p. administration of dextran coupled with dexamethasone in diet-induced obesity and NASH murine models. Chronic administration effects were evaluated by histology and gene expression analysis in adipose tissue and liver samples. In vitro crosstalk between human ATMs and hepatic stellate cells (HSCs) and liver spheroids was performed. ResultsPatients with NAFLD presented an increased accumulation of pro-inflammatory ATMs that correlated with hepatic fibrosis. Long-term modulation of ATMs significantly reduced pro-inflammatory phenotype and ameliorated adipose tissue inflammation. Moreover, ATMs modulation was associated with an improvement in steatosis and hepatic inflammation and significantly reduced fibrosis progression in an experimental NASH model. In vitro, the reduction of the pro-inflammatory phenotype of human ATMs with dextran–dexamethasone treatment reduced the secretion of inflammatory chemokines and directly attenuated the pro-fibrogenic response in HSCs and liver spheroids. ConclusionsPro-inflammatory ATMs increase in parallel with fibrosis degree in patients with NAFLD and their modulation in an experimental NASH model improves liver fibrosis, uncovering the potential of ATMs as a therapeutic target to mitigate liver fibrosis in NAFLD. Impact and implicationsWe report that human adipose tissue pro-inflammatory macrophages correlate with hepatic fibrosis in non-alcoholic fatty liver disease (NAFLD). Furthermore, the modulation of adipose tissue macrophages (ATMs) by dextran-nanocarrier conjugated with dexamethasone shifts the pro-inflammatory phenotype of ATMs to an anti-inflammatory phenotype in an experimental murine model of non-alcoholic steatohepatitis. This shift ameliorates adipose tissue inflammation, hepatic inflammation, and fibrosis. Our results highlight the relevance of adipose tissue in NAFLD pathophysiology and unveil ATMs as a potential target for NAFLD.

1852-PUB: The Effect of Lactic Acid Fermented Sake Lees in a NASH-HCC Mouse Model

Nonalcoholic steatohepatitis (NASH) is a liver disease characterized by fatty liver and cirrhosis that van lead to hepatocellular carcinoma. Although NASH prevalence is increasing worldwide, no cure has yet been established. Sake-lees, which are a by-product of sake refinement, have liver-protecting properties. Lactic acid fermented sake lees (FSL) is a food made by lactic acid fermentation of lees, which are then dealcoholized. Although FSL is regarded as a pro-health supplement, whether it has hepatoprotective effects remains unclear. To address this, we used a murine model of NASH to determine whether FSL could suppress progression of the disease. FSL supplementation significantly suppressed the increase in blood glucose impeded the progression of NASH. Protein analysis revealed that FSL also attenuated the increased expression of inflammatory markers. We infer that dietary FSL has anti-inflammatory and anti-hyperglycemic effects that contribute to the inhibition of NASH progression. Disclosure H. Suzuki: None. K. Watanabe: None. S. Arumugam: None. M. Afrin: None. Y. Matsubayashi: None. H. Sone: Research Support; Novo Nordisk, Astellas Pharma Inc., Kyowa Kirin Co., Ltd., Taisho Pharmaceutical Holdings Co., Ltd., Ono Pharmaceutical Co., Ltd., Eisai Co., Ltd., Takeda Pharmaceutical Co., Ltd. Funding Japan Society for the Promotion of Science (22K17772)

Butyrate limits inflammatory macrophage niche in NASH

Immune cell infiltrations with lobular inflammation in the background of steatosis and deregulated gut-liver axis are the cardinal features of non-alcoholic steatohepatitis (NASH). An array of gut microbiota-derived metabolites including short-chain fatty acids (SCFA) multifariously modulates NASH pathogenesis. However, the molecular basis for the favorable impact of sodium butyrate (NaBu), a gut microbiota-derived SCFA, on the immunometabolic homeostasis in NASH remains elusive. We show that NaBu imparts a robust anti-inflammatory effect in lipopolysaccharide (LPS) stimulated or classically activated M1 polarized macrophages and in the diet-induced murine NASH model. Moreover, it impedes monocyte-derived inflammatory macrophage recruitment in liver parenchyma and induces apoptosis of proinflammatory liver macrophages (LM) in NASH livers. Mechanistically, by histone deactylase (HDAC) inhibition NaBu enhanced acetylation of canonical NF-κB subunit p65 along with its differential recruitment to the proinflammatory gene promoters independent of its nuclear translocation. NaBu-treated macrophages thus exhibit transcriptomic signatures that corroborate with a M2-like prohealing phenotype. NaBu quelled LPS-mediated catabolism and phagocytosis of macrophages, exhibited a differential secretome which consequently resulted in skewing toward prohealing phenotype and induced death of proinflammatory macrophages to abrogate metaflammation in vitro and in vivo. Thus NaBu could be a potential therapeutic as well as preventive agent in mitigating NASH.

Modulating sphingosine 1-phosphate receptor signaling skews intrahepatic leukocytes and attenuates murine nonalcoholic steatohepatitis.

Sphingosine 1-phosphate (S1P) is a bioactive sphingolipid associated with nonalcoholic steatohepatitis (NASH). Immune cell-driven inflammation is a key determinant of NASH progression. Macrophages, monocytes, NK cells, T cells, NKT cells, and B cells variably express S1P receptors from a repertoire of 5 receptors termed S1P1 - S1P5. We have previously demonstrated that non-specific S1P receptor antagonism ameliorates NASH and attenuates hepatic macrophage accumulation. However, the effect of S1P receptor antagonism on additional immune cell populations in NASH remains unknown. We hypothesized that S1P receptor specific modulation may ameliorate NASH by altering leukocyte recruitment. A murine NASH model was established by dietary feeding of C57BL/6 male mice with a diet high in fructose, saturated fat, and cholesterol (FFC) for 24 weeks. In the last 4 weeks of dietary feeding, the mice received the S1P1,4,5 modulator Etrasimod or the S1P1 modulator Amiselimod, daily by oral gavage. Liver injury and inflammation were determined by histological and gene expression analyses. Intrahepatic leukocyte populations were analyzed by flow cytometry, immunohistochemistry, and mRNA expression. Alanine aminotransferase, a sensitive circulating marker for liver injury, was reduced in response to Etrasimod and Amiselimod treatment. Liver histology showed a reduction in inflammatory foci in Etrasimod-treated mice. Etrasimod treatment substantially altered the intrahepatic leukocyte populations through a reduction in the frequency of T cells, B cells, and NKT cells and a proportional increase in CD11b+ myeloid cells, polymorphonuclear cells, and double negative T cells in FFC-fed and control standard chow diet (CD)-fed mice. In contrast, FFC-fed Amiselimod-treated mice showed no changes in the frequencies of intrahepatic leukocytes. Consistent with the improvement in liver injury and inflammation, hepatic macrophage accumulation and the gene expression of proinflammatory markers such as Lgals3 and Mcp-1 were decreased in Etrasimod-treated FFC-fed mice. Etrasimod treated mouse livers demonstrated an increase in non-inflammatory (Marco) and lipid associated (Trem2) macrophage markers. Thus, S1P1,4,5 modulation by Etrasimod is more effective than S1P1 antagonism by Amiselimod, at the dose tested, in ameliorating NASH, likely due to the alteration of leukocyte trafficking and recruitment. Etrasimod treatment results in a substantial attenuation of liver injury and inflammation in murine NASH.

Restoring polyamine levels by supplementation of spermidine modulates hepatic immune landscape in murine model of NASH

AimsTo determine if changes in polyamines metabolism occur during non-alcoholic steatohepatitis (NASH) in human patients and mice, as well as to assess systemic and liver-specific effects of spermidine administration into mice suffering from advanced NASH. Materials and methodsHuman fecal samples were collected from 50 healthy and 50 NASH patients. For the preclinical studies C57Bl6/N male mice fed GAN or NIH-31 diet for 6 months were ordered from Taconic and liver biopsy was performed. Based on severity of liver fibrosis, body composition and body weight, the mice from both dietary groups were randomized into another two groups: half receiving 3 mM spermidine in drinking water, half normal water for subsequent 12 weeks. Body weight was measured weekly and glucose tolerance and body composition were assessed at the end. Blood and organs were collected during necropsy, and intrahepatic immune cells were isolated for flow cytometry analysis. ResultsMetabolomic analysis of human and murine feces confirmed that levels of polyamines decreased along NASH progression. Administration of exogenous spermidine to the mice from both dietary groups did not affect body weight, body composition or adiposity. Moreover, incidence of macroscopic hepatic lesions was higher in NASH mice receiving spermidine. On the other hand, spermidine normalized numbers of Kupffer cells in the livers of mice suffering from NASH, although these beneficial effects did not translate into improved liver steatosis or fibrosis severity. ConclusionLevels of polyamines decrease during NASH in mice and human patients but spermidine administration does not improve advanced NASH.

Abstract 4605: Chronic VEGF-C signaling exacerbates the progression of non-alcoholic steatohepatitis and hepatocarcinoma through endothelial VEGFR2 and VEGFR3

Abstract Obesity, aging, and metabolic diseases contribute to non-alcoholic fatty liver disease (NAFLD) that can progress to non-alcoholic steatohepatitis (NASH) due to ongoing inflammation and pathological angiogenesis. At present, NASH is a leading cause of cirrhosis, hepatocarcinoma cancer (HCC) and liver transplant within the United States. Pathological angiogenesis of liver sinusoidal endothelial cells (LSECs) is one of the hallmarks of liver injury that disrupt normal LSEC physiology. Therefore, strategies which target factors involved in LSEC dysregulation may improve the progression of hepatic diseases. Examination of a human tissue microarray identified increased levels of vascular endothelial growth factor-C (VEGF-C) in NASH livers compared with healthy individuals. Additionally, single nuclei RNA sequencing and immunofluorescent staining revealed that the receptors for VEGF-C, VEGFR2 and VEGFR3, are primarily expressed by the LSECs. Using murine models of NASH, we further investigated the role of VEGF-C during disease progression. Chronic over expression of VEGF-C by adeno-associated viral (AAV) infection in mice fed a western diet with carbon tetrachloride injections increased NASH progression compared with control AAV infected NASH mice. Interestingly, overexpression of VEGF-C C156S, a variant of VEGF-C which exclusively binds to VEGFR3, resulted in significantly increased hepatic steatosis, but only minimal fibrosis. To determine whether blockade of VEGF-C signaling would delay disease progression, we administered lenvatinib, a tyrosine kinase inhibitor which primarily blocks VEGFR2 and VEGFR3 at low doses, to NASH mice. We discovered that low dose lenvatinib resulted in significantly decreased amount of fibrosis, steatosis, and tumor formation. Analysis of vehicle treated and lenvatinib treated livers by single nuclei RNA sequencing uncovered significant changes in endothelial cell genes associated with extracellular interactions and inflammation, as well as hepatocyte genes involved in lipid synthesis and metabolism. Taken together, these findings indicate that chronic VEGF-C production in NASH plays a role in promoting liver fibrosis and steatosis as well as HCC development, and that blockade of the downstream receptors for VEGF-C, VEGFR2 and VEGFR3, may be a promising therapeutic strategy to mitigate disease severity. Citation Format: Seock-Won Youn, Jason W.-L. Eng, Bhairavi Swaminathan, Pamela Teneqexhi, Rahul Vadakath, Jan K. Kitajewski. Chronic VEGF-C signaling exacerbates the progression of non-alcoholic steatohepatitis and hepatocarcinoma through endothelial VEGFR2 and VEGFR3. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4605.

Deficient chaperone-mediated autophagy in macrophage aggravates inflammation of nonalcoholic steatohepatitis by targeting Nup85.

Nonalcoholic steatohepatitis (NASH), a more severe subtype of nonalcoholic fatty liver disease, can cause cirrhosis and hepatocellular carcinoma. Macrophages play critical roles in initiating and maintaining NASH-induced liver inflammation and fibrosis. However, the underlying molecular mechanism of macrophage chaperone-mediated autophagy (CMA) in NASH remains unclear. We aimed to investigate the effects of macrophage-specific CMA on liver inflammation and identify a potential therapeutic target for NASH treatment. The CMA function of liver macrophages was detected using Western blot, quantitative reverse transcription-polymerase chain reaction (RT-qPCR) and flow cytometry. By constructing myeloid-specific CMA deficiency mice, we evaluated the effects of deficient CMA of macrophages on monocyte recruitment, liver injury, steatosis and fibrosis in NASH mice. A label-free mass spectrometry was utilized to screen the substrates of CMA in macrophages and their mutual interactions. The association between CMA and its substrate was further examined by immunoprecipitation, Western blot and RT-qPCR. A typical hallmark in murine NASH models was impaired CMA function in hepatic macrophages. Monocyte-derived macrophages (MDM) were the dominant macrophage population in NASH, and CMA function was impaired in MDM. CMA dysfunction aggravated liver-targeted recruitment of monocyte and promoted steatosis and fibrosis. Mechanistically, Nup85 functions as a substrate for CMA and its degradation was inhibited in CMA-deficient macrophages. Inhibition of Nup85 attenuated the steatosis and monocyte recruitment caused by CMA deficiency in NASH mice. We proposed that the impaired CMA-induced Nup85 degradation aggravated monocyte recruitment, promoting liver inflammation and disease progression of NASH.