NASH Progression Research Articles

SAT079 - Novel endosomal trafficking adaptor for the regulation of NAFLD to NASH progression

SAT079 - Novel endosomal trafficking adaptor for the regulation of NAFLD to NASH progression

Promotion of nonalcoholic steatohepatitis by RNA N6-methyladenosine reader IGF2BP2 in mice

AbstractNonalcoholic steatohepatitis (NASH) has emerged as the major cause of end-stage liver diseases. However, an incomplete understanding of its molecular mechanisms severely dampens the development of pharmacotherapies. In the present study, through systematic screening of genome-wide mRNA expression from three mouse models of hepatic inflammation and fibrosis, we identified IGF2BP2, an N6-methyladenosine modification reader, as a key regulator that promotes NASH progression in mice. Adenovirus or adeno-associated virus-mediated overexpression of IGF2BP2 could induce liver steatosis, inflammation, and fibrosis in mice, at least in part, by increasing Tab2 mRNA stability. Besides, hepatic overexpression of IGF2BP2 mimicked gene expression profiles and molecular pathways of human NASH livers. Of potential clinical significance, IGF2BP2 expression is significantly upregulated in the livers of NASH patients. Moreover, knockdown of IGF2BP2 substantially alleviated liver injury, inflammation, and fibrosis in diet-induced NASH mice. Taken together, our findings reveal an important role of IGF2BP2 in NASH, which may provide a new therapeutic target for the treatment of NASH.

Vildagliptin alleviates liver fibrosis in NASH diabetic rats via modulation of insulin resistance, oxidative stress, and inflammatory cascades

AimsThis study investigates the therapeutic potential of Vilda in a NASH model with liver fibrosis and elucidates the underlying molecular mechanisms. Main methodsTo induce NASH, male Sprague-Dawley rats were fed a high-fat diet for 24 weeks with a single dose of STZ (40 mg/kg, IP). Vilda was orally administered at two doses (10 and 20 mg/kg) for 20 weeks. Key findingsThe induction of NASH was validated by abnormalities in hepatotoxicity indices, lipid profile, oxidative stress markers, and pathologically by marked fat deposition in hepatic tissues together with severe inflammatory cell infiltration. Moreover, NASH-affected rats demonstrated reduced insulin sensitivity manifested as elevated fasting blood glucose levels and disrupted homeostasis model assessment for insulin resistance. Vilda, at both doses, effectively abrogated all these pathological features of NASH. Mechanistically, these hepatoprotective properties of Vilda can be attributed to its antioxidant effects, anti-inflammatory effects (by inhibiting the TNF-α, NF-κB, JNK, and JAK/STAT pathways), and insulin-sensitizing effect (by upregulating the IRS-1/PI3K/Akt pathway). Besides, Vilda successfully counteracted NASH-associated liver fibrosis by downregulating the TGF-β1 pathway. SignificanceThe hepatoprotective and antifibrotic effects of Vilda were mostly dose-dependent. Collectively, this study offered a promising therapeutic avenue for Vilda as a novel strategy for counteracting the pathological progression of NASH and associated liver fibrosis.

1337-P: Sex-Specific Variation in Lipid Metabolism in Response to Nutritional Stress Is Associated with Differences in NASH Progression

Nonalcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease in the US, encompassing a disease spectrum defined by steatosis, inflammation (NASH) , and fibrosis. Although the incidence of NASH is less in women compared with men, the mechanistic basis for this phenomenon is unclear. The aim of this study was to use high-resolution LC-MS/MS proteomics to determine sex-specific differences in liver protein abundance in healthy mice and in response to NASH that may contribute to protection in females. Male and female C57BL6J mice were fed regular chow (RC) or fast food (FF) diet (40% fat, 0.15% cholesterol, 42 g/L high-fructose corn syrup drinking water; n=18-20/g) to induce NASH. Liver weight and steatosis were significantly increased in male and female FF mice compared to RC counterparts, and the effects were more pronounced in males versus females. Plasma insulin and ALT followed similar patterns. Label-free differential mass spectrometry identified 2,917 proteins, where 314 and 445 proteins exhibited statistically significant changes in expression associated with sex and diet, and 2proteins showed a significant sex x diet interaction. Unsupervised hierarchical clustering of the 2proteins identified four groups of proteins defined by sex-specific differences in baseline abundance or response to FF-diet. Enrichment analysis of proteins within the four groups identified biological process related to 1) lipid catabolism and synthesis that were upregulated in FF males compared with females; 2) catabolism and oxidation-reduction reactions that were suppressed by FF diet in males but not females and 3) acyl-CoA hydrolase activity and fatty acid oxidation that were higher in RC females than males and induced by FF in males but not females. These data suggest that sex-specific differences in liver lipid metabolism at baseline and in response to nutritional stress may contribute to sexual dimorphism in NASH susceptibility. Disclosure M.Moon: None. A.Murali: None. F.Bello: None. J.Wang: None. M.J.Jurczak: None. Funding National Institutes of Health (DK114012)

Pro-Neurotensin as a Potential Novel Diagnostic Biomarker for Detection of Nonalcoholic Fatty Liver Disease.

Background and AimsCurrently, liver biopsy is the gold standard method for diagnosis of non-alcoholic fatty liver severity. It is critical to develop non-invasive diagnostic method to diagnose nonalcoholic fatty liver rather than invasive techniques. Our case–control study was to address the value of circulating miRNA-122 and serum pro-neurotensin as a potential non-invasive biomarker for the diagnosis of non-alcoholic fatty acid diseases.MethodsClinical assessment, laboratory investigations, and anthropometric measurements were reported for 157 patients with proven NAFLD. Apparently, healthy participants (n=100) were enrolled as a control group. Serum samples were tested for micro-RNAs−122 and pro-neurotensin.ResultsCompared with the control subjects, both mi-RNA-122 and serum proneurotensin levels were increased in NAFLD (p<0.001) and at a cut-off ≥6.83, mi-RNA-122 had 51.0% sensitivity, 70.0% specificity to differentiate NAFLD from healthy controls, while serum proneurotensin had 80.0% sensitivity and 80.0% specificity at a cutoff ≥108.ConclusionThe circulating pro-neurotensin might be used as a novel biomarker for diagnosis of patients with NAFLD, wherefore the integration of a circulating mi-RNA-122 and serum pro-neurotensin could be beneficial to diagnose NAFLD cases. Large-scale studies are needed to investigate the possible role of mi-RNA-122 and pro-neurotensin in the development, progression, and prognosis of NAFLD and NASH.

Discovery of an insulin-induced gene binding compound that ameliorates nonalcoholic steatohepatitis by inhibiting sterol regulatory element-binding protein-mediated lipogenesis.

NASH is associated with high levels of cholesterol and triglyceride (TG) in the liver; however, there is still no approved pharmacological therapy. Synthesis of cholesterol and TG is controlled by sterol regulatory element-binding protein (SREBP), which is found to be abnormally activated in NASH patients. We aim to discover small molecules for treating NASH by inhibiting the SREBP pathway. Here, we identify a potent SREBP inhibitor, 25-hydroxylanosterol (25-HL). 25-HL binds to insulin-induced gene (INSIG) proteins, stimulates the interaction between INSIG and SCAP, and retains them in the endoplasmic reticulum, thereby suppressing SREBP activation and inhibiting lipogenesis. In NASH mouse models, 25-HL lowers levels of cholesterol and TG in serum and the liver, enhances energy expenditure to prevent obesity, and improves insulin sensitivity. 25-HL dramatically ameliorates hepatic steatosis, inflammation, ballooning, and fibrosis through down-regulating the expression of lipogenic genes. Furthermore, 25-HL exhibits both prophylactic and therapeutic efficacies of alleviating NASH and atherosclerosis in amylin liver NASH model diet-treated Ldlr-/- mice, and reduces the formation of cholesterol crystals and associated crown-like structures of Kupffer cells. Notably, 25-HL lowers lipid contents in serum and the liver to a greater extent than lovastatin or obeticholic acid. 25-HL shows a good safety and pharmacokinetics profile. This study provides the proof of concept that inhibiting SREBP activation by targeting INSIG to lower lipids could be a promising strategy for treating NASH. It suggests the translational potential of 25-HL in human NASH and demonstrates the critical role of SREBP-controlled lipogenesis in the progression of NASH by pharmacological inhibition.

Selective PPARα Modulator Pemafibrate and Sodium-Glucose Cotransporter 2 Inhibitor Tofogliflozin Combination Treatment Improved Histopathology in Experimental Mice Model of Non-Alcoholic Steatohepatitis.

Ballooning degeneration of hepatocytes is a major distinguishing histological feature of non-alcoholic steatosis (NASH) progression that can lead to cirrhosis and hepatocellular carcinoma (HCC). In this study, we evaluated the effect of the selective PPARα modulator (SPPARMα) pemafibrate (Pema) and sodium-glucose cotransporter 2 (SGLT2) inhibitor tofogliflozin (Tofo) combination treatment on pathological progression in the liver of a mouse model of NASH (STAM) at two time points (onset of NASH progression and HCC survival). At both time points, the Pema and Tofo combination treatment significantly alleviated hyperglycemia and hypertriglyceridemia. The combination treatment significantly reduced ballooning degeneration of hepatocytes. RNA-seq analysis suggested that Pema and Tofo combination treatment resulted in an increase in glyceroneogenesis, triglyceride (TG) uptake, lipolysis and liberated fatty acids re-esterification into TG, lipid droplet (LD) formation, and Cidea/Cidec ratio along with an increased number and reduced size and area of LDs. In addition, combination treatment reduced expression levels of endoplasmic reticulum stress-related genes (Ire1a, Grp78, Xbp1, and Phlda3). Pema and Tofo treatment significantly improved survival rates and reduced the number of tumors in the liver compared to the NASH control group. These results suggest that SPPARMα and SGLT2 inhibitor combination therapy has therapeutic potential to prevent NASH-HCC progression.

The transcription factor zinc fingers and homeoboxes 2 alleviates NASH by transcriptional activation of phosphatase and tensin homolog.

NASH, which is a common clinical condition predisposing to advanced liver diseases, has become a worldwide epidemic. A large and growing unmet therapeutic need for this condition reflects incomplete understanding of its pathogenesis. In the current study, we identified a transcription factor, zinc fingers and homeoboxes 2 (ZHX2), in hepatocytes as a protective factor against steatohepatitis. We found that hepatic ZHX2 was significantly suppressed in NASH models and steatotic hepatic cells. Hepatocyte-specific ablation of ZHX2 exacerbated NASH-related phenotypes in mice, including lipid accumulation, enhanced inflammation, and hepatic fibrosis. Conversely, hepatocyte-specific overexpression of ZHX2 significantly alleviated the progression of NASH in an experimental setting. Integrated analysis of transcriptomic profiling and chromatin immunoprecipitation sequencing data demonstrated that the phosphatase and tensin homolog (PTEN) was a target gene of ZHX2 in hepatocyte. ZHX2 bound to the promoter of PTEN gene and subsequently promoted the transcription of PTEN, which mediated the beneficial role of ZHX2 against NASH. The current findings demonstrate a protective role of ZHX2 against NASH progression by transcriptionally activating PTEN. These findings shed light on the therapeutic potential of targeting ZHX2 for treating NASH and related metabolic disorders.

Procollagen C-Proteinase Enhancer-1 (PCPE-1) deficiency in mice reduces liver fibrosis but not NASH progression.

Background and aimsNonalcoholic Steatohepatitis (NASH) is a major cause of end-stage liver diseases such as cirrhosis and hepatocellular carcinoma resulting ultimately in increased liver-related mortality. Fibrosis is the main driver of mortality in NASH. Procollagen C-Proteinase Enhancer-1 (PCPE-1) plays a key role in procollagen maturation and collagen fibril formation. To assess its role in liver fibrosis and NASH progression, knock-out mice were evaluated in a dietary NASH model.MethodsGlobal constitutive Pcolce-/- and WT male mice were fed with a Choline Deficient Amino acid defined High Fat Diet (CDA HFD) for 8 weeks. Liver triglycerides, steatosis, inflammation and fibrosis were assessed at histological, biochemical and gene expression levels. In addition, human liver samples from control and NASH patients were used to evaluate the expression of PCPE-1 at both mRNA and protein levels.ResultsPcolce gene deficiency prevented diet-induced liver enlargement but not liver dysfunction. Furthermore, liver triglycerides, steatosis and inflammation were not modified in Pcolce-/- male mice compared to WT under CDA HFD. However, a significant decrease in liver fibrosis was observed in Pcolce-/- mice compared to WT under NASH diet, associated with a decrease in total and insoluble collagen content without any significant modifications in the expression of genes involved in fibrosis and extracellular matrix remodeling. Finally, PCPE-1 protein expression was increased in cirrhotic liver samples from both NASH and Hepatitis C patients.ConclusionsPcolce deficiency limits fibrosis but not NASH progression in CDA HFD fed mice.

Notch-triggered maladaptation of liver sinusoidal endothelium aggravates nonalcoholic steatohepatitis through endothelial nitric oxide synthase.

Although NASH can lead to severe clinical consequences, including cirrhosis and hepatocellular carcinoma, no effective treatment is currently available for this disease. Increasing evidence indicates that LSECs play a critical role in NASH pathogenesis; however, the mechanisms involved in LSEC-mediated NASH remain to be fully elucidated. In the current study, we found that LSEC homeostasis was disrupted and LSEC-specific gene profiles were altered in methionine-choline-deficient (MCD) diet-induced NASH mouse models. Importantly, Notch signaling was found to be activated in LSECs of NASH mice. To then investigate the role of endothelial Notch in NASH progression, we generated mouse lines with endothelial-specific Notch intracellular domain (NICD) overexpression or RBP-J knockout to respectively activate or inhibit Notch signaling in endothelial cells. Notably, endothelial-specific overexpression of the NICD accelerated LSEC maladaptation and aggravated NASH, whereas endothelial cell-specific inhibition of Notch signaling restored LSEC homeostasis and improved NASH phenotypes. Furthermore, we demonstrated that endothelial-specific Notch activation exacerbated NASH by inhibiting endothelial nitric oxide synthase (eNOS) transcription, whereas administration of the pharmacological eNOS activator YC-1 alleviated hepatic steatosis and lipid accumulation resulting from Notch activation. Finally, to explore the therapeutic potential of using Notch inhibitors in NASH treatment, we applied two gamma-secretase inhibitors-DAPT and LY3039478-in an MCD diet-induced mouse model of NASH, and found that both inhibitors effectively ameliorated hepatic steatosis, inflammation, and liver fibrosis. Endothelial-specific Notch activation triggered LSEC maladaptation and exacerbated NASH phenotypes in an eNOS-dependent manner. Genetic and pharmacological inhibition of Notch signaling effectively restored LSEC homeostasis and ameliorated NASH progression.

Endothelial group IVA phospholipase A2 promotes hepatic fibrosis with sinusoidal capillarization in the early stage of non-alcoholic steatohepatitis in mice

AimNon-alcoholic steatohepatitis (NASH) is characterized by steatosis, inflammatory responses and fibrosis. Our previous studies provided evidence that group IVA phospholipase A2 (IVA-PLA2), a key PLA2 isozyme in the arachidonic acid cascade, is involved in the development of NASH. However, which types of cells are critical for the IVA-PLA2-dependent onset and progression of NASH is unclear. We elucidated the effects of the cell-type-specific deficiency of IVA-PLA2 in mice on the development of NASH. Main methodsCell-type-specific IVA-PLA2-conditional knockout (cKO) mice and littermate controls were fed a choline-deficient, L-amino-acid-defined, high-fat diet with 0.1% methionine as a NASH model. The degree of hepatic fibrosis was evaluated by staining with picric acid-Sirius red, and the number of activated hepatic stellate cells was determined by immunoblotting and immunostaining for α-smooth muscle actin. Sinusoidal capillarization was analyzed by scanning electron microscopy. Key findingsThe deposition of collagen and number of activated hepatic stellate cells were markedly reduced in endothelial cell/liver sinusoidal endothelial cell (EC/LSEC)-specific IVA-PLA2 cKO mice but not in hepatocyte-, monocyte/macrophage-, or hepatic stellate cell-specific IVA-PLA2 cKO mice. In addition, EC/LSEC-specific IVA-PLA2-deficient mice showed more fenestrae than control mice fed a CDAHFD, indicating suppression of sinusoidal capillarization. SignificanceThese results suggest that ECs/LSECs contribute to the IVA-PLA2-dependent onset and/or progression of NASH. Endothelial IVA-PLA2 is a promising factor for promoting sinusoidal capillarization and the ensuing HSC activation and fibrosis; thus IVA-PLA2 in ECs/LSECs is a potential therapeutic target for NASH.

Hepatic macrophage targeted siRNA lipid nanoparticles treat non-alcoholic steatohepatitis

HMGB1 is an inflammatory factor produced by macrophages after liver injury, which plays a key role in promoting NASH progression and further developing into liver fibrosis and cirrhosis. In this study, a mannose-modified HMGB1-siRNA loaded stable nucleic acid lipid particle delivery system (mLNP-siHMGB1) was constructed to target liver macrophages with mannose receptor mediation, thereby silencing HMGB1 protein expression and treating NASH. We also examined the effect of co-administration with docosahexaenoic acid (DHA), a kind of unsaturated fatty acid, on NASH. The results showed that mLNP-siHMGB1 could target macrophages through mannose receptors, effectively silence HMGB1 gene, reduce the release of HMGB1 protein in the liver, regulate liver macrophages to be an anti-inflammatory M2 phenotype, effectively reduce hepatic lobular inflammation and bullous steatosis in the liver, and restore the liver function of NASH model mice to a normal level. After 8 weeks of combined treatment with mLNP-siHMGB1 and DHA, the liver function of NASH model mice recovered rapidly and the hepatic steatosis returned to normal level. In view of inflammation, a key factor in the progression of NASH, we provided an actively targeted siRNA delivery system in this study, and clarified the important role of the delivery system in phenotypic regulation of liver macrophages in NASH. In addition, we also demonstrated the effectiveness of DHA co-administration in NASH treatment. This study provided a useful idea and scientific basis for the development of therapeutic strategies for NASH in the future.

The Tumor Suppresor Role of the α1-NA/K-ATPase Signalosome in NASH Related Hepatocellular Carcinoma (HCC)

Background: HCC is the second and fastest-growing cancer related mortality worldwide. Intriguingly, the mechanisms that underpin the tumorigenesis of HCC from NASH are largely unknown. We hypothesized that the growing uncoupled metabolism during NASH progression to HCC follows a disarrangement on the wild type α1-Na/K-ATPase/Src signalosome.

Breviscapine alleviates NASH by inhibiting TGF-β-activated kinase 1-dependent signaling.

Background and AimsNAFLD is a key component of metabolic syndrome, ranging from nonalcoholic fatty liver to NASH, and is now becoming the leading cause of cirrhosis and HCC worldwide. However, due to the complex and unclear pathophysiological mechanism, there are no specific approved agents for treating NASH. Breviscapine, a natural flavonoid prescription drug isolated from the traditional Chinese herb Erigeron breviscapus, exhibits a wide range of pharmacological properties, including effects on metabolism. However, the anti‐NASH efficacy and mechanisms of breviscapine have not yet been characterized.Approach and ResultsWe evaluated the effects of breviscapine on the development of hepatic steatosis, inflammation, and fibrosis in vivo and in vitro under metabolic stress. Breviscapine treatment significantly reduced lipid accumulation, inflammatory cell infiltration, liver injury, and fibrosis in mice fed a high‐fat diet, a high‐fat/high‐cholesterol diet, or a methionine‐ and choline‐deficient diet. In addition, breviscapine attenuated lipid accumulation, inflammation, and lipotoxicity in hepatocytes undergoing metabolic stress. RNA‐sequencing and multiomics analyses further indicated that the key mechanism linking the anti‐NASH effects of breviscapine was inhibition of TGF‐β‐activated kinase 1 (TAK1) phosphorylation and the subsequent mitogen‐activated protein kinase signaling cascade. Treatment with the TAK1 inhibitor 5Z‐7‐oxozeaenol abrogated breviscapine‐mediated hepatoprotection under metabolic stress. Molecular docking illustrated that breviscapine directly bound to TAK1.ConclusionBreviscapine prevents metabolic stress–induced NASH progression through direct inhibition of TAK1 signaling. Breviscapine might be a therapeutic candidate for the treatment of NASH.

S-adenosylmethionine inhibits la ribonucleoprotein domain family member 1 in murine liver and human liver cancer cells.

Methionine adenosyltransferase 1A (MAT1A) is responsible for S-adenosylmethionine (SAMe) biosynthesis in the liver. Mice lacking Mat1a have hepatic SAMe depletion and develop NASH and HCC spontaneously. Several kinases are activated in Mat1a knockout (KO) mice livers. However, characterizing the phospho-proteome and determining whether they contribute to liver pathology remain open for study. Our study aimed to provide this knowledge. We performed phospho-proteomics in Mat1a KO mice livers with and without SAMe treatment to identify SAMe-dependent changes that may contribute to liver pathology. Our studies used Mat1a KO mice at different ages treated with and without SAMe, cell lines, in vitro translation and kinase assays, and human liver specimens. We found that the most striking change was hyperphosphorylation and increased content of La-related protein 1 (LARP1), which, in the unphosphorylated form, negatively regulates translation of 5'-terminal oligopyrimidine (TOP)-containing mRNAs. Consistently, multiple TOP proteins are induced in KO livers. Translation of TOP mRNAs ribosomal protein S3 and ribosomal protein L18 was enhanced by LARP1 overexpression in liver cancer cells. We identified LARP1-T449 as a SAMe-sensitive phospho-site of cyclin-dependent kinase 2 (CDK2). Knocking down CDK2 lowered LARP1 phosphorylation and prevented LARP1-overexpression-mediated increase in translation. LARP1-T449 phosphorylation induced global translation, cell growth, migration, invasion, and expression of oncogenic TOP-ribosomal proteins in HCC cells. LARP1 expression is increased in human NASH and HCC. Our results reveal a SAMe-sensitive mechanism of LARP1 phosphorylation that may be involved in the progression of NASH to HCC.

Melanoma differentiation-Associated gene 5 protects against NASH in mice.

NASH is a complicated disease characterized by hepatocyte steatosis, inflammation infiltration, and liver fibrosis. Accumulating evidence suggests that the innate immunity plays a key role in NASH progression. Here, we aimed to reveal the role of melanoma differentiation-associated gene 5 (MDA5, also known as Ifih1), a conventional innate immune regulator following viral infection, in the progression of NASH and investigate its underlying mechanism. We first examined the expression of MDA5 and found that MDA5 was markedly down-regulated in the livers with NASH in human individuals and mice models. MDA5 overexpression significantly inhibits the free fatty acid-induced lipid accumulation and inflammation in hepatocyte in vitro, whereas MDA5knockdown promotes hepatocyte lipotoxicity. Using hepatocyte-specific Mda5gene knockout and transgenic mice, we found that diet-induced hepatic steatosis, inflammation, and liver fibrosis were markedly exacerbated by Mda5 deficiency but suppressed by Mda5 overexpression. Mechanistically, we found that the activation of apoptosis signal-regulating kinase 1 (ASK1)-mitogen-activated protein kinase pathway was significantly inhibited by MDA5 but enhanced by MDA5 deletion. We further validated that MDA5 directly interacted with ASK1 and suppressed its N-terminal dimerization. Importantly, blockage of ASK1 with adenovirus-expressing dominant negative ASK1 obviously reversed the lipid accumulation and ASK1 pathway activation when Mda5was knocked out. These data indicate that MDA5 is an essential suppressor in NASH. The findings support MDA5 as a regulator of ASK1 and a promising therapeutic target for NASH.

Association between Equol Production Status and Nonalcoholic Steatohepatitis.

Equol is a metabolite of daidzein, a major soybean isoflavone with estrogenic and antioxidant activities. As the production of equol depends on the presence of certain members of the intestinal microflora, not all individuals can produce equol. We examined the relationship between NASH histological features and equol production. In an animal model, obese OLETF rats were intraperitoneally injected with a porcine serum to augment liver fibrogenesis. Equol-rich soy product, SE5-OH was orally administered during the experimental period. Treatment with SE5-OH markedly attenuated the development of liver fibrosis and expression of alpha-smooth muscle actin. In clinical research, 38 NAFLD patients (13 men and 25 women) were included. The degree of fibrosis and ballooning in equol-nonproducers was significantly higher than in equol-producers in women. The percentage of nonproducers with NAFLD activity score (NAS) ≥ 5 was significantly higher than that of producers. None of the histological features were significantly different between nonproducers and producers in men. Decision tree analysis identified predictors for NAS ≥ 5 in women. The status of equol production was the strongest predictor, followed by fasting glucose. Since equol can be noninvasively detected in urine, it can be applied as a screening tool for the progression of NASH in women.

Salidroside Activates the AMP-Activated Protein Kinase Pathway to Suppress Nonalcoholic Steatohepatitis in Mice.

NASH is becoming a leading cause of liver cirrhosis and HCC. Salidroside (p-hydroxyphenethyl-β-D-glucoside; SAL) has various biological and pharmacological activities, including anti-inflammatory, -oxidant, and -cancer activities. However, the therapeutic effect and underlying molecular mechanism of SAL in NASH remain to be further clarified. In this study, we found that SAL alleviated lipid accumulation and inflammatory response in primary hepatocytes after palmitic acid/oleic acid (PO) stimulation. In addition, SAL effectively prevented high-fat/high-cholesterol (HFHC)-diet-induced NASH progression by regulating glucose metabolism dysregulation, insulin resistance, lipid accumulation, inflammation, and fibrosis. Mechanistically, integrated RNA-sequencing and bioinformatic analysis showed that SAL promoted AMPK-signaling pathway activation in vitro and in vivo, and this finding was further verified by determining the phosphorylation levels of AMPK. Furthermore, the protective effects of SAL on lipid accumulation and inflammation in hepatocytes and livers induced by PO or HFHC stimulation were blocked by AMPK interruption. Our studies demonstrate that SAL protects against metabolic-stress-induced NASH progression through activation of AMPK signaling, indicating that SAL could be a potential drug component for NASH therapy.

The Role of RECK in Hepatobiliary Neoplasia Reveals Its Therapeutic Potential in NASH.

Non-alcoholic fatty liver disease (NAFLD) is a multimorbidity disorder ranging from excess accumulation of fat in the liver (steatosis) to steatohepatitis (NASH) and end-stage cirrhosis, and the development of hepatocellular carcinoma (HCC) in a subset of patients. The defining features of NASH are inflammation and progressive fibrosis. Currently, no pharmaceutical therapies are available for NAFLD, NASH and HCC; therefore, developing novel treatment strategies is desperately needed. Reversion Inducing Cysteine Rich Protein with Kazal motifs (RECK) is a well-known modifier of the extracellular matrix in hepatic remodeling and transition to HCC. More recently, its role in regulating inflammatory and fibrogenic processes has emerged. Here, we summarize the most relevant findings that extend our current understanding of RECK as a regulator of inflammation and fibrosis, and its induction as a potential strategy to blunt the development and progression of NASH and HCC.

Guanine Nucleotide‐Binding Protein G(i) Subunit Alpha 2 Exacerbates NASH Progression by Regulating Peroxiredoxin 1–Related Inflammation and Lipophagy

NASH is an advanced stage of liver disease accompanied by lipid accumulation, inflammation, and liver fibrosis. Guanine nucleotide-binding protein G(i) subunit alpha-2 (GNAI2) is a member of the "inhibitory" class of α-subunits, and recent studies showed that Gnai2 deficiency is known to cause reduced weight in mice. However, the role of GNAI2 in hepatocytes, particularly in the context of liver inflammation and lipid metabolism, remains to be elucidated. Herein, we aim to ascertain the function of GNAI2 in hepatocytes and its impact on the development of NASH. Human liver tissues were obtained from NASH patients and healthy persons to evaluate the expression and clinical relevance of GNAI2. In addition, hepatocyte-specific Gnai2-deficient mice (Gnai2hep-/- ) were fed either a Western diet supplemented with fructose in drinking water (WDF) for 16weeks or a methionine/choline-deficient diet (MCD) for 6weeks to investigate the regulatory role and underlying mechanism of Gnai2 in NASH. GNAI2 was significantly up-regulated in liver tissues of patients with NASH. Following feeding with WDF or MCD diets, livers from Gnai2hep-/- mice had reduced steatohepatitis with suppression of markers of inflammation and an increase in lipophagy compared to Gnai2flox/flox mice. Toll-like receptor 4 signals through nuclear factor kappa B to trigger p65-dependent transcription of Gnai2. Intriguingly, immunoprecipitation, immunofluorescence, and mass spectrometry identified peroxiredoxin 1 (PRDX1) as a binding partner of GNAI2. Moreover, the function of PRDX1 in the suppression of TNF receptor-associated factor 6 ubiquitin-ligase activity and glycerophosphodiester phosphodiesterase domain-containing 5-related phosphatidylcholine metabolism was inhibited by GNAI2. Suppression of GNAI2 combined with overexpression of PRDX1 reversed the development of steatosis and fibrosis in vivo. GNAI2 is a major regulator that leads to the development of NASH. Thus, inhibition of GNAI2 could be an effective therapeutic target for the treatment of NASH.