Pathogenesis Of NASH Research Articles

Machine learning based identification potential feature genes for prediction of drug efficacy in nonalcoholic steatohepatitis animal model

BackgroundNonalcoholic Steatohepatitis (NASH) results from complex liver conditions involving metabolic, inflammatory, and fibrogenic processes. Despite its burden, there has been a lack of any approved food-and-drug administration therapy up till now.PurposeUtilizing machine learning (ML) algorithms, the study aims to identify reliable potential genes to accurately predict the treatment response in the NASH animal model using biochemical and molecular markers retrieved using bioinformatics techniques.MethodsThe NASH-induced rat models were administered various microbiome-targeted therapies and herbal drugs for 12 weeks, these drugs resulted in reducing hepatic lipid accumulation, liver inflammation, and histopathological changes. The ML model was trained and tested based on the Histopathological NASH score (HPS); while (0–4) HPS considered Improved NASH and (5–8) considered non-improved, confirmed through rats’ liver histopathological examination, incorporates 34 features comprising 20 molecular markers (mRNAs-microRNAs-Long non-coding-RNAs) and 14 biochemical markers that are highly enriched in NASH pathogenesis. Six different ML models were used in the proposed model for the prediction of NASH improvement, with Gradient Boosting demonstrating the highest accuracy of 98% in predicting NASH drug response.FindingsFollowing a gradual reduction in features, the outcomes demonstrated superior performance when employing the Random Forest classifier, yielding an accuracy of 98.4%. The principal selected molecular features included YAP1, LATS1, NF2, SRD5A3-AS1, FOXA2, TEAD2, miR-650, MMP14, ITGB1, and miR-6881-5P, while the biochemical markers comprised triglycerides (TG), ALT, ALP, total bilirubin (T. Bilirubin), alpha-fetoprotein (AFP), and low-density lipoprotein cholesterol (LDL-C).ConclusionThis study introduced an ML model incorporating 16 noninvasive features, including molecular and biochemical signatures, which achieved high performance and accuracy in detecting NASH improvement. This model could potentially be used as diagnostic tools and to identify target therapies.

Ablation of histone methyltransferase Suv39h2 in hepatocytes attenuates NASH in mice

AimsNon-alcoholic steatohepatitis (NASH) is characterized by aberrant lipid metabolism in hepatocytes. We investigated the involvement of a histone H3K9 methyltransferase Suv39h2 in the pathogenesis of NASH. Methods and materialsNASH is induced by feeding the mice with a high-fat high-carbohydrate (HFHC) diet or a high-fat choline-deficient amino acid defined (HFD-CDAA) diet. The Suv39h2f/f mice were crossbred with the Alb-Cre mice to specifically delete Suv39h2 in hepatocytes. Key findingsAblation of Suv39h2 in hepatocytes improved insulin sensitivity of the mice fed either the HFHC diet or the CDAA-HFD diet. Importantly, Suv39h2 deletion significantly ameliorated NAFLD as evidenced by reduced lipid accumulation, inflammation, and fibrosis in the liver. RNA-seq uncovered Vanin-1 (Vnn1) as a novel transcriptional target for Suv39h2. Mechanistically, Suv39h2 repressed Vnn1 transcription in hepatocytes exposed to free fatty acids. Consistently, Vanin-1 knockdown normalized lipid accumulation in Suv39h2-null hepatocytes. Importantly, a significant correlation between Suv39h2, Vanin-1, and hepatic triglyceride levels was identified in NASH patients. SignificanceOur study uncovers a novel mechanism whereby Suv39h2 may contribute to NASH pathogenesis and suggests that targeting the Suv39h2-Vanin-1 axis may yield novel therapeutic solutions against NASH.

Non-alcoholic hepatic steatosis and its relation with metabolic syndrome

Objective: The aim of this study is to investigate the relationship between Non-Alcoholic Hepatic Steatosis (NASH) and Metabolic Syndrome (MS). Bibliographic review: NASH is a common liver condition in western industrialized countries, affecting individuals who do not consume alcohol. The pathogenesis of NASH involves environmental, genetic, and gut microbiota factors, and there is a strong association between NASH and MS, a condition that increases the risk of cardiovascular disease and type 2 diabetes. The relationship between NASH and MS is complex, with both sharing features such as obesity, insulin resistance and inflammation. The study analyzed 13 articles and found a strong association between NASH and MS. Patients with NASH often have features of MS, including type 2 diabetes, obesity, and hypertension. Furthermore, the presence of MS is related to a higher risk of liver disease progression. The relationship between these conditions appears to be driven by factors such as elevated glucose, insulin resistance and increased visceral fat. Final considerations: NASH and MS are conditions that pose significant public health challenges, especially in developed countries. The prevention and control of these conditions are closely linked to the promotion of lifestyle changes, including a healthy diet and physical exercise. These changes can have a positive impact on the incidence and progression of both NASH and MS, improving quality of life and reducing the risks associated with these pathological conditions. In addition, the importance of considering genetics and other individual factors in the evaluation and management of these multifactorial conditions is highlighted.

STREM2 is a plasma biomarker for human NASH and promotes hepatocyte lipid accumulation.

Pathogenetic mechanisms of the progression of NAFL to advanced NASH coupled with potential noninvasive biomarkers and novel therapeutic targets are active areas of investigation. The recent finding that increased plasma levels of a protein shed by myeloid cells -soluble Triggering Receptor Expressed on Myeloid cells 2 (sTREM2) -may be a biomarker for NASH has received much interest. We aimed to test sTREM2 as a biomarker for human NASH and investigate the role of sTREM2 in the pathogenesis of NASH. We conducted studies in both humans (comparing patients with NASH vs. NAFL) and in mice (comparing different mouse models of NASH) involving measurements of TREM2 gene and protein expression levels in the liver as well as circulating sTREM2 levels in plasma. We investigated the pathogenetic role of sTREM2 in hepatic steatosis using primary hepatocytes and bone marrow derived macrophages. RNA sequencing analysis of livers from patients with NASH or NAFL as well as livers from 2 mouse models of NASH revealed elevated TREM2 expression in patients/mice with NASH as compared with NAFL. Plasma levels of sTREM2 were significantly higher in a well-characterized cohort of patients with biopsy-proven NASH versus NAFL (area under receiver-operating curve 0.807). Mechanistic studies revealed that cocultures of primary hepatocytes and macrophages with an impaired ability to shed sTREM2 resulted in reduced hepatocyte lipid droplet formation on palmitate stimulation, an effect that was counteracted by the addition of exogenous sTREM2 chimeric protein. Conversely, exogenous sTREM2 chimeric protein increased lipid droplet formation, triglyceride content, and expression of the lipid transporter CD36 in hepatocytes. Furthermore, inhibition of CD36 markedly attenuated sTREM2-induced lipid droplet formation in mouse primary hepatocytes. Elevated levels of sTREM2 due to TREM2 shedding may directly contribute to the pathogenesis of NAFLD by promoting hepatocyte lipid accumulation, as well as serving as a biomarker for distinguishing patients with NASH versus NAFL. Further investigation of sTREM2 as a clinically useful diagnostic biomarker and of the therapeutic effects of targeting sTREM2 in NASH is warranted.

Rho-associated protein kinase 1 inhibition in hepatocytes attenuates nonalcoholic steatohepatitis.

NASH is the progressive form of NAFLD characterized by lipotoxicity, hepatocyte injury, tissue inflammation, and fibrosis. Previously, Rho-associated protein kinase (ROCK) 1 has been implicated in lipotoxic signaling in hepatocytes in vitro and high-fat diet-induced lipogenesis in vivo. However, whether ROCK1 plays a role in liver inflammation and fibrosis during NASH is unclear. Here, we hypothesized that pathogenic activation of ROCK1 promotes murine NASH pathogenesis. Patients with NASH had increased hepatic ROCK1 expression compared with patients with fatty liver. Similarly, hepatic ROCK1 levels and activity were increased in mice with NASH induced by a western-like diet that is high in fat, fructose, and cholesterol (FFC). Hepatocyte-specific ROCK1 knockout mice on the FFC diet displayed a decrease in liver steatosis, hepatic cell death, liver inflammation, and fibrosis compared with littermate FFC-fed controls. Mechanistically, these effects were associated with a significant attenuation of myeloid cell recruitment. Interestingly, myeloid cell-specific ROCK1 deletion did not affect NASH development in FFC-fed mice. To explore the therapeutic opportunities, mice with established NASH received ROCKi, a novel small molecule kinase inhibitor of ROCK1/2, which preferentially accumulates in liver tissue. ROCK inhibitor treatment ameliorated insulin resistance and decreased liver injury, inflammation, and fibrosis. Genetic or pharmacologic inhibition of ROCK1 activity attenuates murine NASH, suggesting that ROCK1 may be a therapeutic target for treating human NASH.

Accumulation of α-synuclein in hepatocytes in nonalcoholic steatohepatitis and its usefulness in pathological diagnosis

BackgroundsNonalcoholic steatohepatitis (NASH) is characterized by fat deposition, inflammation, and hepatocellular damage. The diagnosis of NASH is confirmed pathologically, and hepatocyte ballooning is an important finding for definite diagnosis. Recently, α-synuclein deposition in multiple organs was reported in Parkinson’s disease. Since it was reported that α-synuclein is taken up by hepatocytes via connexin 32, the expression of α-synuclein in the liver in NASH is of interest. The accumulation of α-synuclein in the liver in NASH was investigated. Immunostaining for p62, ubiquitin, and α-synuclein was performed, and the usefulness of immunostaining in pathological diagnosis was examined. MethodsLiver biopsy tissue specimens from 20 patients were evaluated. Several antibodies against α-synuclein, as well as antibodies against connexin 32, p62, and ubiquitin were used for immunohistochemical analyses. Staining results were evaluated by several pathologists with varying experience, and the diagnostic accuracy of ballooning was compared. ResultsPolyclonal α-synuclein antibody, not the monoclonal antibody, reacted with eosinophilic aggregates in ballooning cells. Expression of connexin 32 in degenerating cells was also demonstrated. Antibodies against p62 and ubiquitin also reacted with some of the ballooning cells. In the pathologists’ evaluations, the highest interobserver agreement was obtained with hematoxylin and eosin (H&E)-stained slides, followed by slides immunostained for p62 and α-synuclein, and there were cases with different results between H&E staining and immunostaining ConclusionThese results indicate the incorporation of degenerated α-synuclein into ballooning cells, suggesting the involvement of α-synuclein in the pathogenesis of NASH. The combination of immunostaining including polyclonal α-synuclein may contribute to improving the diagnosis of NASH.

Loss of CEACAM1 in endothelial cells causes hepatic fibrosis

ObjectivesHepatocytic CEACAM1 plays a critical role in NASH pathogenesis, as bolstered by the development of insulin resistance, visceral obesity, steatohepatitis and fibrosis in mice with global Ceacam1 (Cc1) deletion. In contrast, VECadCre+Cc1fl/fl mice with endothelial loss of Cc1 manifested insulin sensitivity with no visceral obesity despite elevated NF-κB signaling and increased systemic inflammation. We herein investigated whether VECadCre+Cc1fl/fl male mice develop hepatic fibrosis and whether this is mediated by increased production of endothelin1 (ET1), a transcriptional NF-κB target. MethodsVECadCre+Et1.Cc1fl/fl mice with combined endothelial loss of Cc1/Et1 genes were generated. Histological and immunohistochemical analyses were conducted on their livers and on liver tissue biopsies from adult patients undergoing bariatric surgery or from patients with NASH diagnosis receiving liver transplant. ResultsHepatic fibrosis and inflammatory infiltration developed in VECadCre+Cc1fl/fl liver parenchyma. This was preceded by increased ET1 production and reversed with combined endothelial loss of Et1. Conditioned media from VECadCre+Cc1fl/fl, but not VECadCre+Et1.Cc1fl/fl primary liver endothelial cells activated wild-type hepatic stellate cells; a process inhibited by bosentan, an ETAR/ETBR dual antagonist. Consistently, immunohistochemical analysis of liver biopsies from patients with NASH showed a decline in endothelial CEACAM1 in parallel with increased plasma endothelin1 levels and progression of hepatic fibrosis stage. ConclusionsThe data demonstrated that endothelial CEACAM1 plays a key role in preventing hepatic fibrogenesis by reducing autocrine endothelin1 production.

Membrane phospholipid remodeling modulates nonalcoholic steatohepatitis progression by regulating mitochondrial homeostasis.

NASH, characterized by inflammation and fibrosis, is emerging as a leading etiology of HCC. Lipidomics analyses in the liver have shown that the levels of polyunsaturated phosphatidylcholine (PC) are decreased in patients with NASH, but the roles of membrane PC composition in the pathogenesis of NASH have not been investigated. Lysophosphatidylcholine acyltransferase 3 (LPCAT3), a phospholipid (PL) remodeling enzyme that produces polyunsaturated PLs, is a major determinant of membrane PC content in the liver. The expression of LPCAT3 and the correlation between its expression and NASH severity were analyzed in human patient samples. We examined the effect of Lpcat3 deficiency on NASH progression using Lpcat3 liver-specific knockout (LKO) mice. RNA sequencing, lipidomics, and metabolomics were performed in liver samples. Primary hepatocytes and hepatic cell lines were used for in vitro analyses. We showed that LPCAT3 was dramatically suppressed in human NASH livers, and its expression was inversely correlated with NAFLD activity score and fibrosis stage. Loss of Lpcat3 in mouse liver promotes both spontaneous and diet-induced NASH/HCC. Mechanistically, Lpcat3 deficiency enhances reactive oxygen species production due to impaired mitochondrial homeostasis. Loss of Lpcat3 increases inner mitochondrial membrane PL saturation and elevates stress-induced autophagy, resulting in reduced mitochondrial content and increased fragmentation. Furthermore, overexpression of Lpcat3 in the liver ameliorates inflammation and fibrosis of NASH. These results demonstrate that membrane PL composition modulates the progression of NASH and that manipulating LPCAT3 expression could be an effective therapeutic for NASH.

LCN2 contributes to the improvement of nonalcoholic steatohepatitis by 8-Cetylberberine

AimsNonalcoholic steatohepatitis (NASH) is becoming one of the most common causes of liver transplantation and hepatocellular carcinoma, but no specific drugs are FDA-approved to treat it. 8-cetylberberine (CBBR), which is a long-chain alkane derivative of berberine, exhibits potent pharmacological activities and improves metabolism performance. The aim of this study is to explore the function and mechanism of CBBR against NASH. Materials and methodsL02 and HepG2 hepatocytes were treated with the medium containing palmitic acids and oleic acids (PO) and incubated with CBBR for 12 h, then the levels of lipid accumulation were tested by kits or western blots. C57BL/6 J mice were fed with a high-fat diet or a high-fat/high-cholesterol diet. CBBR (15 mg/kg or 30 mg/kg) was orally administered for 8 weeks. Liver weight, steatosis, inflammation, and fibrosis were evaluated. Transcriptomic indicated the target of CBBR in NASH. Key findingsCBBR significantly reduced lipid accumulation, inflammation, liver injury, and fibrosis in NASH mice. CBBR also decreased lipid accumulation and inflammation in PO-induced L02 and HepG2 cells. RNA sequencing and bioinformatics analysis indicated that CBBR inhibited the pathways and key regulators associated with lipid accumulation, inflammation, and fibrosis in the pathogenesis of NASH. Mechanically, CBBR may prevent NASH via inhibiting LCN2, as proved by the finding that the anti-NASH effect of CBBR was more obvious in PO-stimulated HepG2 cells treated with LCN2 overexpression. SignificanceOur work provides an insight into the effectiveness of CBBR in improving metabolic-stress-caused NASH as well as the mechanism by regulating LCN2.

OR02-3 SLAMF-1 mediates Hepatocyte Death in Non-Alcoholic Fatty Liver Disease and is Plasma values correlates with the Severity of the Disease in Human

Abstract The signaling lymphocytic activation molecule 1 (SLAMF1) exerts a role in regulating the immune response to some viruses and parasite infections. In the present study, we identified SLAMF1 as a potential therapeutic target and biomarker for Non-Alcoholic Fatty Liver Disease (NASH) in humans. We found that SLAMF1 is highly expressed in liver samples from mice and humans with NASH. Our data also show SLAMF1 is detected in plasma, and its levels correlate with the severity of the disease. To uncover a molecular role for SLAMF1 in hepatocytes, we treated two hepatocyte cell lines (HepG2 and HuH-7) and primary mouse hepatocyte with palmitic acid (PA) to induce lipotoxicity, characteristic of NASH. We found that PA treatment leads to a significant increase in SLAMF1 protein levels in the cell lines and primary hepatocytes. We found an increase in HepG2 cell apoptosis in response to PA treatment, and downregulation of SLAMF1 in hepatocytes with siRNA improved cell viability and reduced cytotoxicity, apoptosis, and the expression of inflammatory mediators. Moreover, we found that PA-treated HepG2 cells secrete SLAMF1 in the culture medium, which may be mediating part of these effects through paracrine action. Our findings suggest a role for SLAMF1 in NASH's pathogenesis and highlight SLAMF1 as a reliable clinical biomarker of the disease. Presentation: Saturday, June 11, 2022 12:00 p.m. - 12:15 p.m.

Intrahepatic paracrine signaling by cardiotrophin-like cytokine factor 1 ameliorates diet-induced NASH in mice.

The mammalian liver harbors heterogeneous cell types that communicate via local paracrine signaling. Recent studies have delineated the transcriptomic landscape of the liver in NASH that provides insights into liver cell heterogeneity, intercellular crosstalk, and disease-associated reprogramming. However, the nature of intrahepatic signaling and its role in NASH progression remain obscure. Here, we performed transcriptomic analyses and identified cardiotrophin-like cytokine factor 1 (CLCF1), a member of the IL-6 family cytokines, as a cholangiocyte-derived paracrine factor that was elevated in the liver from diet-induced NASH mice and patients with NASH. Adenovirus-associated virus-mediated overexpression of CLCF1 in the liver ameliorated NASH pathologies in two diet-induced NASH models in mice, illustrating that CLCF1 induction may serve an adaptive and protective role during NASH pathogenesis. Unexpectedly, messenger RNA and protein levels of leukemia inhibitory factor receptor (LIFR), a subunit of the receptor complex for CLCF1, were markedly downregulated in NASH liver. Hepatocyte-specific inactivation of LIFR accelerated NASH progression in mice, supporting an important role of intrahepatic cytokine signaling in maintaining tissue homeostasis under metabolic stress conditions. Together, this study sheds light on the molecular nature of intrahepatic paracrine signaling during NASH pathogenesis and uncovers potential targets for therapeutic intervention.

PIDDosome-SCAP crosstalk controls high-fructose-diet-dependent transition from simple steatosis to steatohepatitis

Sterol deficiency triggers SCAP-mediated SREBP activation, whereas hypernutrition together with ER stress activates SREBP1/2 via caspase-2. Whether these pathways interact and how they are selectively activated by different dietary cues are unknown. Here, we reveal regulatory crosstalk between the two pathways that controls the transition from hepatosteatosis to steatohepatitis. Hepatic ER stress elicited by NASH-inducing diets activates IRE1 and induces expression of the PIDDosome subunits caspase-2, RAIDD, and PIDD1, along with INSIG2, an inhibitor of SCAP-dependent SREBP activation. PIDDosome assembly activates caspase-2 and sustains IRE1 activation. PIDDosome ablation or IRE1 inhibition blunt steatohepatitis and diminish INSIG2 expression. Conversely, while inhibiting simple steatosis, SCAP ablation amplifies IRE1 and PIDDosome activation and liver damage in NASH-diet-fed animals, effects linked to ER disruption and preventable by IRE1 inhibition. Thus, the PIDDosome and SCAP pathways antagonistically modulate nutrient-induced hepatic ER stress to control non-linear transition from simple steatosis to hepatitis, a key step in NASH pathogenesis.

SAT031 - Small changes in the metabolism of bile acids by the gut microbiota are associated to NASH pathogenesis

SAT031 - Small changes in the metabolism of bile acids by the gut microbiota are associated to NASH pathogenesis

SAT043 - Unraveling the transcriptional dynamics of NASH pathogenesis affecting atherosclerosis development

SAT043 - Unraveling the transcriptional dynamics of NASH pathogenesis affecting atherosclerosis development

Characterizing Hepatic Inflammation upon SGLT2 Inhibition in Diabetic TallyHo Mice

By 2030, Diabetes is estimated to become the 7th leading cause of death worldwide with roughly 90‐95% of all cases attributed to Type 2 diabetes (T2D). A common comorbidity of T2D is Non‐Alcoholic Fatty Liver Disease (NAFLD), characterized by the presence of lipid accumulation with or without hepatic steatosis (NASH). While the pathogenesis of NAFLD and NASH is not entirely understood, it is associated with insulin resistance, inflammation, and hyperlipidemia. Recently, sodium‐glucose co‐transporter 2 (SGLT2) inhibitors have emerged as a treatment option for patients with T2D. This drug effectively blocks renal glucose reabsorption and in turn, improves glycemic control. It is also associated with positive renal and cardiovascular outcomes. Given the attenuation of hyperglycemia, we sought to determine if SGLT2 inhibitors also offer protection from the development of NAFLD and NASH. To test this, spontaneously diabetic male and female TallyHo mice were maintained on either a control or high milk fat diet (60%) for 24‐weeks in the continued presence or absence of Empagliflozin, one of the most well‐characterized SGLT2 inhibitors on the market. As expected, at the conclusion of 24 weeks, blood glucose values were significantly lowered in the male mice treated with Empagliflozin. We also detected a reduction in hepatic lipid accumulation by both MRI and biochemical analysis. To determine if these protective effects correlated with a reduction in inflammation, we performed a large‐scale screen of more than 60 inflammatory markers on both plasma and livers collected from the high‐fat diet‐fed male mice. The data revealed that Empagliflozin attenuates systemic inflammation; we detected a downregulation in circulating pro‐inflammatory cytokines (CD30 ligand, IL‐1α, IL‐4, IL‐9, TIMP1, TPO) and an upregulation in MIP‐1γ, an anti‐inflammatory cytokine (p<0.05 for all cytokines). In contrast, we observed indications of increased inflammation in the Empagliflozin‐treated livers. Protein expression of cleaved caspase, the active form of the inflammatory‐driven protein, was elevated when compared to non‐treated milk fat diet‐fed mice (which was already elevated compared to normal chow controls). In addition, we noted heightened levels of five pro‐inflammatory cytokines (IL‐3, IL‐6, CCL2, M‐CSF, CCL1) while there was downregulation of another three (p40/p70, TNFSF8, CCL3; p<0.05). Efforts are currently underway to confirm the expression of these common inflammatory markers and to elucidate the mechanism behind the dysregulated hepatic inflammatory pathway upon SGLT2 inhibition.

T cells: Friends and foes in NASH pathogenesis and hepatocarcinogenesis.

In association with the pandemic spreading of obesity and metabolic syndrome, the prevalence of NAFLD-related HCC is increasing almost exponentially. In recent years, many of the underlining multifactorial causes of NAFLD have been identified, and the cellular mechanisms sustaining disease development have been dissected up to the single-cell level. However, there is still an urgent need to provide clinicians with more therapeutic targets, with particular attention on NAFLD-induced HCC, where immune checkpoint inhibitors do not work as efficiently. Whereas much effort has been invested in elucidating the role of innate immune response in the hepatic NAFLD microenvironment, only in the past decade have novel critical roles been unraveled for T cells in driving chronic inflammation toward HCC. The metabolic and immune microenvironment interact to recreate a tumor-promoting and immune-suppressive terrain, responsible for resistance to anticancer therapy. In this article, we will review the specific functions of several T-cell populations involved in NAFLD and NAFLD-driven HCC. We will illustrate the cellular crosstalk with other immune cells, regulatory networks or stimulatory effects of these interactions, and role of the metabolic microenvironment in influencing immune cell functionality. Finally, we will present the pros and cons of the current therapeutic strategies against NAFLD-related HCC and delineate possible novel approaches for the future.

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.

Intestinal Dysbiosis, the Tryptophan Pathway and Nonalcoholic Steatohepatitis.

Non-alcoholic fatty liver disease (NAFLD) progresses from simple steatosis to steatohepatitis (NASH), which may then progress to the development of cirrhosis and hepatocarcinoma. NASH is characterized by both steatosis and inflammation. Control of inflammation in NASH is a key step for the prevention of disease progression to severe sequalae. Intestinal dysbiosis has been recognized to be an important causal factor in the pathogenesis of NASH, involving both the accumulation of lipids and aggravation of inflammation. The effects of gut dysbiosis are mediated by adverse shifts of various intestinal commensal bacterial genera and their associated metabolites such as butyrate, tryptophan, and bile acids. In this review, we focus on the roles of tryptophan and its metabolites in NASH in association with intestinal dysbiosis and discuss possible therapeutic implications.

Research Progress of Multi-Target Drugs in the Treatment of Non-Alcoholic Steatohepatitis

Non-alcoholic steatohepatitis is a clinical syndrome with pathological changes similar to alcoholic steatohepatitis without a history of excessive alcohol consumption, and is a key stage of reversible progression to liver fibrosis, which can further develop into malignant diseases such as cirrhosis or even liver cancer if preventive measures are not taken. The pathogenesis of NASH is complex, and there are no any effective drugs for NASH. It is difficult for single-target drugs to achieve good therapeutic effects, and are accompanied by strong side effects, and many of them are terminated in the clinical trial stage. Multi-target drugs are not easy to produce drug resistance, and can exert synergistic effects on multiple targets to maximize drug efficacy and minimize adverse side effects, and has a good effect on the treatment of complex diseases. This article summarizes the multi-target drugs for the treatment of NASH, and provides a reference for finding new drugs for the treatment of NASH.

Bile Acid Profiling in Mouse Biofluids and Tissues.

Bile acids (BAs) serve as important signaling molecules and are endogenous ligands of nuclear and cell membrane receptors to regulate physiological and pathological processes. BA synthesis and metabolism have been impaired in NASH patients because of liver injury, inflammation or obstruction of bile ducts. On the other hand, the changes in BA composition might alter the activation status of various cell signaling pathways and contribute to NASH pathogenesis. Due to the rapidly increasing interests in the roles of individual BA in disease development, this chapter will focus on the method for analyzing individual BA profile in mouse biofluids and tissues by high-performance liquid chromatography coupled with ion trap mass spectrometry (HPLC-MS).