Association of HSD17B13 and PNPLA3 With Liver Enzymes and Fibrosis in Hispanic/Latino Individuals of Diverse Genetic Ancestries.

BACKGROUND & AIMS: Genetic variants affecting liver disease risk vary among racial and ethnic groups. Hispanics/Latinos in the United States have a high prevalence of PNPLA3 I148M, which increases liver disease risk, and a low prevalence of HSD17B13 predicted loss-of-function (pLoF) variants, which reduce risk. Less is known about the prevalence of liver disease-associated variants among Hispanic/Latino subpopulations defined by country of origin and genetic ancestry. We evaluated the prevalence of HSD17B13 pLoF variants and PNPLA3 I148M, and their associations with quantitative liver phenotypes in Hispanic/Latino participants from an electronic health record-linked biobank in New York City. METHODS: This study included 8739 adult Hispanic/Latino participants of the BioMe biobank with genotyping and exome sequencing data. We estimated the prevalence of Hispanic/Latino individuals harboring HSD17B13 and PNPLA3 variants, stratified by genetic ancestry, and performed association analyses between variants and liver enzymes and Fibrosis-4 (FIB-4) scores. RESULTS: Individuals with ancestry from Ecuador and Mexico had the lowest frequency of HSD17B13 pLoF variants (10%/7%) and the highest frequency of PNPLA3 I148M (54%/65%). These ancestry groups had the highest outpatient alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, and the largest proportion of individuals with a FIB-4 score greater than 2.67. HSD17B13 pLoF variants were associated with reduced ALT level (P = .002), AST level (P < .001), and FIB-4 score (P = .045). PNPLA3 I148M was associated with increased ALT level, AST level, and FIB-4 score (P < .001 for all). HSD17B13 pLoF variants mitigated the increase in ALT conferred by PNPLA3 I148M (P = .006). CONCLUSIONS: Variation in HSD17B13 and PNPLA3 variants across genetic ancestry groups may contribute to differential risk for liver fibrosis among Hispanic/Latino individuals.

Sphingosine kinase 1 mediates sexual dimorphism in fibrosis in a mouse model of NASH.

OBJECTIVE: Men with non-alcoholic fatty liver disease (NAFLD) are more likely to progress to non-alcoholic steatohepatitis (NASH) and liver fibrosis than women. However, the underlying molecular mechanisms of this dimorphism is unclear. We have previously shown that mice with global deletion of SphK1, the enzyme that produces the bioactive sphingolipid metabolite sphingosine 1-phosphate (S1P), were protected from development of NASH. The aim of this study was to elucidate the role of hepatocyte-specific SphK1 in development of NASH and to compare its contribution to hepatosteatosis in male and female mice. METHODS: We assessed mouse livers in early-stage fibrosis induced by high fat feeding, using single harmonic generation microscopy, LC-MS/MS analysis of hydroxyproline levels, and expression of fibrosis markers. We identified an antifibrotic intercellular signaling mechanism by culturing primary mouse hepatocytes alongside, and in co-culture with, LX2 hepatic stellate cells. RESULTS: We generated hepatocyte-specific SphK1 knockout mice (SphK1-hKO). Unlike the global knockout, SphK1-hKO male mice were not protected from diet-induced steatosis, inflammation, or fibrogenesis. In contrast, female SphK1-hKO mice were protected from inflammation. Surprisingly, however, in these female mice, there was a ∼10-fold increase in the fibrosis markers Col1α1 and 2-3 fold induction of alpha smooth muscle actin and the pro-fibrotic chemokine CCL5. Because increased fibrosis in female SphK1-hKO mice occurred despite an attenuated inflammatory response, we investigated the crosstalk between hepatocytes and hepatic stellate cells, central players in fibrosis. We found that estrogen stimulated release of S1P from female hepatocytes preventing TGFß-induced expression of Col1α1 in HSCs via S1PR3. CONCLUSIONS: The results revealed a novel pathway of estrogen-mediated cross-talk between hepatocytes and HSCs that may contribute to sex differences in NAFLD through an anti-fibrogenic function of the S1P/S1PR3 axis. This pathway is susceptible to pharmacologic manipulation, which may lead to novel therapeutic strategies.

Alcohol-associated fibrosis in females is mediated by female-specific activation of lysine demethylases KDM5B and KDM5C.

Alcohol-associated liver disease is a major cause of alcohol-related mortality. However, the mechanisms underlying disease progression are not fully understood. Recently we found that liver molecular pathways are altered by alcohol consumption differently in males and females. We were able to associate these sex-specific pathways with two upstream regulators: H3K4-specific demethylase enzymes KDM5B and KDM5C. Mice were fed the Lieber-DeCarli alcohol liquid diet for 3 weeks or a combination of a high-fat diet with alcohol in water for 16 weeks (western diet alcohol model [WDA] model). To assess the role of histone demethylases, mice were treated with AAV-shControl, AAV-shKdm5b, and/or AAV-shKdm5c and/or AAV-shAhR vectors. Gene expression and epigenetic changes after Kdm5b/5c knockdown were assessed by RNA-sequencing and H3K4me3 chromatin immunoprecipitation analysis. We found that less than 5% of genes affected by Kdm5b/Kdm5c knockdown were common between males and females. In females, Kdm5b/Kdm5c knockdown prevented fibrosis development in mice fed the WDA alcohol diet for 16 weeks and decreased fibrosis-associated gene expression in mice fed the Lieber-DeCarli alcohol liquid diet. In contrast, fibrosis was not affected by Kdm5b/Kdm5c knockdown in males. We found that KDM5B and KDM5C promote fibrosis in females through down-regulation of the aryl hydrocarbon receptor (AhR) pathway components in hepatic stellate cells. Kdm5b/Kdm5c knockdown resulted in an up-regulation of Ahr, Arnt, and Aip in female but not in male mice, thus preventing fibrosis development. Ahr knockdown in combination with Kdm5b/Kdm5c knockdown restored profibrotic gene expression. Conclusion: KDM5 demethylases contribute to differences between males and females in the alcohol response in the liver. The KDM5/AhR axis is a female-specific mechanism of fibrosis development in alcohol-fed mice.

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

AIM: Non-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 METHODS: Cell-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 FINDINGS: The 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. SIGNIFICANCE: These 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.

Pterostilbene ameliorates the disrupted Adars expression and improves liver fibrosis in DEN-induced liver injury in Wistar rats: A novel potential effect.

The knowledge of RNA editing modifications and its subsequent proteomic diversity in is still limited and represents only the tip of the iceberg. Adenosine to inosine (A-to-I) RNA editing is the most prevalent in RNA editome with a rising role for ADARgene family as a major regulator of the dynamic landscape of RNA editing. This study aimed at evaluating the potential chemopreventive effects of the epigenetic regulator "pterostilbene" in diethylnitrosamine (DEN)-exposedrat model. Consequently, the hepatic Adars expression was investigated as a possible mechanism for mediation of the putative pterostilbene-induced chemopreventive effect. The effects of administration of pterostilbene were investigated on the structural changes, immunohistochemical staining, liver function test, serum alpha feto-protein (AFP), IL-6, and hepatic Adar1 and Adar2 relative gene expression at the beginning and at the 6th week of the study. Pterostilbene attenuated DEN-induced liver injury, improves hepatocyte parrafin-1 (Hep Par-1), decreases heat shock protein 70 (HSP70), improved AFP, serum albumin, transaminases, IL-6 with alleviation of disturbed hepatic Adar1 and Adar2 expression. This study spotlights the role of pterostilbene in attenuation of DEN-induced liver injury which could be mediated, at least partially, through the alleviation of the aberrant expression of Adar enzymes. Yet, more in-depth studies are needed to further elucidate the molecular mechanisms underlying the effects of pterostilbene on RNA editing enzymes.

JQ-1 ameliorates schistosomiasis liver fibrosis by suppressing JAK2 and STAT3 activation.

Schistosomiasis is a serious parasitic infection caused by Schistosoma. The parasite deposits eggs in the host liver, causing inflammation that activates hepatic stellate cells (HSCs), which leads to liver fibrosis. Currently, there is no effective therapy for liver fibrosis; thus, treatments are urgently needed. Therefore, in the present study, mice infected with Schistosoma japonicum were treated with JQ-1, a small-molecule bromodomain inhibitor with reliable anti-tumor and anti-inflammatory activities. The fibrotic area of the liver measured by computer-assisted morphometric analysis and the expression levels of the cytoskeletal protein alpha smooth muscle actin (α-SMA) and of collagen assessed by quantitative PCR, Western blot and immunohistochemistry were significantly decreased in the liver following JQ-1 treatment compared with vehicle-treated controls. Total RNA was extracted from the liver of JQ-1-treated Schistosoma-infected mice for RNA-sequencing analysis. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes analyses indicated that JQ-1 affected biological processes and the expression of cellular components known to play key roles in the transdifferentiation of HSCs to myofibroblasts. In vitro treatment with JQ-1 of JS-1 cells, a mouse HSC line, indicated that JQ-1 significantly inhibited JS-1 proliferation but had no effect on JS-1 activity, senescence, or apoptosis. Western blot results showed that JQ-1 inhibited the expression levels of phosphorylated JAK2 and phosphorylated STAT3 without altering expression levels of these non-phosphorylated proteins. Taken together, these findings suggested that JQ-1 treatment ameliorated S. japonicum egg-induced liver fibrosis, at least in part, by suppressing HSC activation and proliferation through the inhibition of JAK2/STAT3 signaling. These results lay a foundation for the development of novel approaches to treat and control liver fibrosis caused by S. japonicum.

TRIM proteins in fibrosis.

Fibrosis is an outcome of tissue repair after different types of injuries. The homeostasis of extracellular matrix is broken, and excessive deposition occurs, affecting the normal function of tissues and organs, which could become prostrated in serious cases.Finding a suitable target to regulate the repair process and reduce the damage caused by fibrosis is a hot research topic at present. The TRIM family is number of one of the E3 ubiquitin ligase subfamilies and participates in various biological processes including intracellular signal transduction, apoptosis, autophagy, and immunity by regulating the ubiquitination of target proteins. For the past few years, the important role of TRIM in the occurrence and development of fibrosis has been gradually revealed. In this review, we focus on the recent emerging topics on TRIM proteins in the regulation of fibrosis, fibrosis-related cytokines and pathways.

Rimonabant ameliorates hepatic ischemia/reperfusion injury in rats: Involvement of autophagy via modulating ERK- and PI3K/AKT-mTOR pathways.

Hepatic ischemia/reperfusion (HIR), which can result in severe liver injury and dysfunction, is usually associated with autophagy and endocannabinoid system derangements. Whether or not the modulation of the autophagic response following HIR injury is involved in the hepatoprotective effect of the cannabinoid receptor 1(CB1R) antagonist rimonabant remains elusive and is the aim of the current study. Rats pre-treated with rimonabant (3 mg/kg) or vehicle underwent 30 min hepatic ischemia followed by 6 hrs. reperfusion. Liver injury was evaluated by serum ALT, AST, bilirubin (total and direct levels) and histopathological examination. The inflammatory, profibrotic and oxidative responses were investigated by assessing hepatic tumor necrosis factor α (TNFα), nuclear factor kappa B (NF-κB), transforming growth factor (TGF-ß), lipid peroxidation and reduced glutathione. The hepatic levels of CB1R and autophagic markers p62, Beclin-1, and LC3 as well as the autophagic signaling inhibitors ERK1/2, PI3K, Akt and mTOR were also determined. Rimonabant significantly attenuated HIR-induced increases in hepatic injury, inflammation, profibrotic responses and oxidative stress and improved the associated pathological features. Rimonabant modulated the expression of p62, Beclin-1, and LC3, down-regulated CB1R, and dcreased pERK1/2, PI3K, Akt, and mTOR activities. The current study suggests that rimonabant can protect the liver from IR injury at least in part by inducing autophagy, probably by modulating ERK- and/or PI3K/AKT-mTOR signaling.

Selective Acetyl-CoA Carboxylase 1 Inhibitor Improves Hepatic Steatosis and Hepatic Fibrosis in a Preclinical Nonalcoholic Steatohepatitis Model.

Acetyl-CoA carboxylase (ACC) 1 and ACC2 are essential rate-limiting enzymes that synthesize malonyl-CoA (M-CoA) from acetyl-CoA. ACC1 is predominantly expressed in lipogenic tissues and regulates the de novo lipogenesis flux. It is upregulated in the liver of patients with nonalcoholic fatty liver disease (NAFLD), which ultimately leads to the formation of fatty liver. Therefore, selective ACC1 inhibitors may prevent the pathophysiology of NAFLD and nonalcoholic steatohepatitis (NASH) by reducing hepatic fat, inflammation, and fibrosis. Many studies have suggested ACC1/2 dual inhibitors for treating NAFLD/NASH; however, reports on selective ACC1 inhibitors are lacking. In this study, we investigated the effects of compound-1, a selective ACC1 inhibitor for treating NAFLD/NASH, using preclinical in vitro and in vivo models. Compound-1 reduced M-CoA content and inhibited the incorporation of [14C] acetate into fatty acids in HepG2 cells. Additionally, it reduced hepatic M-CoA content and inhibited de novo lipogenesis in C57BL/6J mice after a single dose. Furthermore, compound-1 treatment of 8 weeks in Western diet-fed melanocortin 4 receptor knockout mice-NAFLD/NASH mouse model-improved liver hypertrophy and reduced hepatic triglyceride content. The reduction of hepatic M-CoA by the selective ACC1 inhibitor was highly correlated with the reduction in hepatic steatosis and fibrosis. These findings support further investigations of the use of this ACC1 inhibitor as a new treatment of NFLD/NASH. SIGNIFICANCE STATEMENT: This is the first study to demonstrate that a novel selective inhibitor of acetyl-CoA carboxylase (ACC) 1 has anti-nonalcoholic fatty liver disease (NAFLD) and anti-nonalcoholic steatohepatitis (NASH) effects in preclinical models. Treatment with this compound significantly improved hepatic steatosis and fibrosis in a mouse model. These findings support the use of this ACC1 inhibitor as a new treatment for NAFLD/NASH.

TVB-2640 (FASN Inhibitor) for the Treatment of Nonalcoholic Steatohepatitis: FASCINATE-1, a Randomized, Placebo-Controlled Phase 2a Trial.

BACKGROUND & AIMS: Increased de novo lipogenesis creates excess intrahepatic fat and lipotoxins, propagating liver damage in nonalcoholic steatohepatitis. TVB-2640, a fatty acid synthase inhibitor, was designed to reduce excess liver fat and directly inhibit inflammatory and fibrogenic pathways. We assessed the safety and efficacy of TVB-2640 in patients with nonalcoholic steatohepatitis in the United States. METHODS: 3V2640-CLIN-005 (FASCINATE-1) was a randomized, placebo-controlled, single-blind study at 10 US sites. Adults with ≥8% liver fat, assessed by magnetic resonance imaging proton density fat fraction, and evidence of liver fibrosis by magnetic resonance elastography ≥2.5 kPa or liver biopsy were eligible. Ninety-nine patients were randomized to receive placebo or 25 mg or 50 mg of TVB-2640 (orally, once-daily for 12 weeks). The primary end points of this study were safety and relative change in liver fat after treatment. RESULTS: Liver fat increased in the placebo cohort by 4.5% relative to baseline; in contrast TVB-2640 reduced liver fat by 9.6% in the 25-mg cohort (n = 30; least squares mean: -15.5%; 95% confidence interval, -31.3 to -0.23; P = .053), and 28.1% in the 50-mg cohort (n = 28; least squares mean: -28.0%; 95% confidence interval, -44.5 to -11.6; P = .001). Eleven percent of patients in the placebo group achieved a ≥30% relative reduction of liver fat compared to 23% in the 25-mg group, and 61% in the 50-mg group (P < .001). Secondary analyses showed improvements of metabolic, pro-inflammatory and fibrotic markers. TVB-2640 was well tolerated; adverse events were mostly mild and balanced among the groups. CONCLUSIONS: TVB-2640 significantly reduced liver fat and improved biochemical, inflammatory, and fibrotic biomarkers after 12 weeks, in a dose-dependent manner in patients with nonalcoholic steatohepatitis. ClinicalTrials.gov, Number NCT03938246.

PPARα agonist fenofibrate attenuates iron-induced liver injury in mice by modulating the Sirt3 and ß-catenin signaling.

Iron accumulation is frequently associated with chronic liver diseases. However, our knowledge on how iron contributes to the liver injury is limited. Aberrant Wnt/ß-catenin signaling is a hallmark of several hepatic pathologies. We recently reported that peroxisome proliferator-activated receptor α (PPARα) agonist, fenofibrate, prevents iron-induced oxidative stress and ß-catenin signaling by chelating the iron. Sirtuin3 (Sirt3), a type of NAD+-dependent deacetylase, that plays a critical role in metabolic regulation was found to prevent ischemia reperfusion injury (IRI) by normalizing the Wnt/ß-catenin pathway. In the present study, we explored if fenofibrate prevents iron-induced liver injury by regulating the Sirt3 and ß-catenin signaling. In vitro and in vivo iron treatment resulted in the downregulation of PPARα, Sirt3, active ß-catenin, and its downstream target gene c-Myc in the mouse liver. Pharmacological activation of Sirt3, both in vitro and in vivo, by Honokiol (HK), a known activator of Sirt3, abrogated the inhibitory effect of iron overload on active ß-catenin expression and prevented the iron-induced upregulation of α smooth muscle actin (αSMA) and TGFß expression. Intrinsically, PPARα knockout mice showed significant downregulation of hepatic Sirt3 levels. In addition, treatment of iron overload mice with PPARα agonist fenofibrate reduced hepatic iron accumulation and prevented iron-induced downregulation of liver Sirt3 and active ß-catenin, mitigating the progression of fibrosis. Thus, our results establish a novel link between hepatic iron and PPARα, Sirt3, and ß-catenin signaling. Further exploration on the mechanisms by which fenofibrate ameliorates iron-induced liver injury likely has significant therapeutic impact on iron-associated chronic liver diseases.NEW & NOTEWORTHY Hepatic intracellular iron accumulation has been implicated in the pathophysiology of chronic liver diseases. In this study, we identified a novel mechanism involved in the progression of fibrosis. Excess iron accumulation in liver caused downregulation of PPARα-Sirt3-Wnt signaling leading to fibrosis. This work has significant translational potential as PPARα agonist fenofibrate could be an attractive therapeutic drug for the treatment of liver disorders associated with iron overload.

FTZ attenuates liver steatosis and fibrosis in the minipigs with type 2 diabetes by regulating the AMPK signaling pathway.

Fufang Zhenzhu Tiaozhi formula (FTZ), a preparation of Chinese herbal medicine, has various pharmacological properties, such as hypoglycemic, hypolipidemic, anticoagulant, and anti-inflammatory activities. Hepatocyte apoptosis is a marker of nonalcoholic steatohepatitis (NASH) and contributes to liver injury, fibrosis, and inflammation. Given the multiple effects of FTZ, we investigated whether FTZ can be a therapeutic agent for NASH and its mechanism. In the present study, we observed that FTZ treatment had an obviously favorable influence on hepatic steatosis and fibrosis in the histopathologic features of type 2 diabetes mellitus (T2DM) and coronary heart disease (CHD) with NASH minipigs. In addition, immunohistochemical analysis showed increased expression of the fibrotic marker α-smooth muscle actin (α-SMA), and a TUNEL assay revealed increased apoptotic positive hepatic cells in the liver tissues of the model group. Furthermore, FTZ administration reduced the increased expression of α-SMA, and FTZ inhibited apoptosis by affecting Bcl-2/Bax and cleaved caspase-3 expression. Mechanistically, our data suggested that FTZ treatment attenuated hepatic steatosis and fibrosis via the adenosine monophosphate-activated protein kinase (AMPK) pathway. In vitro studies showed that FTZ also attenuated intracellular lipid accumulation in HepG2 cells exposed to palmitic acid (PA) and oleic acid (OA). FTZ upregulated the expression levels of P-AMPK and BCL-2 and downregulated BAX. The changes induced by FTZ were reversed by Compound C, an inhibitor of AMPK. In conclusion, FTZ attenuated NASH by ameliorating steatosis and hepatocyte apoptosis, which is attributable to the regulation of the AMPK pathway.

Gamma-glutamyl transpeptidase elevation is associated with metabolic syndrome, hepatic steatosis, and fibrosis in patients with nonalcoholic fatty liver disease: A community-based cross-sectional study.

This study aimed to analyze the association between elevated gamma-glutamyl transpeptidase (GGT) and metabolic syndrome (MetS), hepatic steatosis, and fibrosis in patients with nonalcoholic fatty liver disease (NAFLD). From August 2013 to August 2018, a community-based study was conducted in the northeastern part of Taiwan. Patients who underwent abdominal ultrasonography (US) and had no history of alcoholic liver disease were included. According to a US examination showing fatty liver degree, 1566 patients with NAFLD were divided into four groups: normal GGT, isolated GGT elevation, isolated alanine aminotransferase (ALT) elevation, and both GGT and ALT elevation groups. Further 1147 participants with normal serum ALT, GGT, and the abdominal US were included as the control group. GGT levels were associated with high sensitivity C-reactive protein, lower adiponectin, diabetes mellitus, and chronic kidney disease. A stepwise increase in odds ratio (OR) for MetS was found in the normal GGT group (OR = 1.71), isolated GGT elevation group (OR = 3.06), isolated ALT elevation (OR = 4.00), and both GGT + ALT elevation group (OR = 4.17) than the control group. Linear regression analysis revealed a positive association between GGT/ALT value and hepatic steatosis degree, GGT value, and degree of hepatic fibrosis. Hence, GGT elevation is associated with MetS, hepatic steatosis, and fibrosis in patients with NAFLD.

Histone deacetylase­2: A potential regulator and therapeutic target in liver disease (Review).

Histone acetyltransferases are responsible for histone acetylation, while histone deacetylases (HDACs) counteract histone acetylation. An unbalanced dynamic between histone acetylation and deacetylation may lead to aberrant chromatin landscape and chromosomal function. HDAC2, a member of class I HDAC family, serves a crucial role in the modulation of cell signaling, immune response and gene expression. HDAC2 has emerged as a promising therapeutic target for liver disease by regulating gene transcription, chromatin remodeling, signal transduction and nuclear reprogramming, thus receiving attention from researchers and clinicians. The present review introduces biological information of HDAC2 and its physiological and biochemical functions. Secondly, the functional roles of HDAC2 in liver disease are discussed in terms of hepatocyte apoptosis and proliferation, liver regeneration, hepatocellular carcinoma, liver fibrosis and non­alcoholic steatohepatitis. Moreover, abnormal expression of HDAC2 may be involved in the pathogenesis of liver disease, and its expression levels and pharmacological activity may represent potential biomarkers of liver disease. Finally, research on selective HDAC2 inhibitors and non­coding RNAs relevant to HDAC2 expression in liver disease is also reviewed. The aim of the present review was to improve understanding of the multifunctional role and potential regulatory mechanism of HDAC2 in liver disease.

The usefulness of noninvasive liver stiffness assessment using shear-wave elastography for predicting liver fibrosis in children.

BACKGROUND: Pediatric patients with liver disease require noninvasive monitoring to evaluate the risk of fibrosis progression. This study aimed to identify the significant factors affecting liver stiffness values using two-dimensional shear-wave elastography (2D-SWE), and determine whether liver stiffness can predict the fibrosis stage of various childhood liver diseases. METHODS: This study included 30 children (22 boys and 8 girls; mean age, 5.1 ± 6.1 years; range, 7 days-17.9 years) who had undergone biochemical evaluation, 2D-SWE examination, histopathologic analysis of fibrosis grade (F0 to F3), assessment of necroinflammatory activity, and steatosis grading between August 2016 and March 2020. The liver stiffness from 2D-SWE was compared between fibrosis stages using Kruskal-Wallis analysis. Factors that significantly affected liver stiffness were evaluated using univariate and multivariate linear regression analyses. The diagnostic performance was determined from the area under the receiver operating curve (AUC) values of 2D-SWE liver stiffness. RESULTS: Liver stiffness at the F0-1, F2, and F3 stages were 7.9, 13.2, and 21.7 kPa, respectively (P < 0.001). Both fibrosis stage and necroinflammatory grade were significantly associated with liver stiffness (P < 0.001 and P = 0.021, respectively). However, in patients with alanine aminotransferase (ALT) levels below 200 IU/L, the only factor affecting liver stiffness was fibrosis stage (P = 0.030). The liver stiffness value could distinguish significant fibrosis (≥ F2) with an AUC of 0.950 (cutoff value, 11.3 kPa) and severe fibrosis (F3 stage) with an AUC of 0.924 (cutoff value, 18.1 kPa). The 2D-SWE values for differentiating significant fibrosis were 10.5 kPa (≥ F2) and 18.1 kPa (F3) in patients with ALT levels below 200 IU/L. CONCLUSION: The liver stiffness values on 2D-SWE can be affected by both fibrosis and necroinflammatory grade and can provide excellent diagnostic performance in evaluating the fibrosis stage in various pediatric liver diseases. However, clinicians should be mindful of potential confounders, such as necroinflammatory activity or transaminase level, when performing 2D-SWE measurements for liver fibrosis staging.

Indoleamine 2,3-dioxygenase 1 limits hepatic inflammatory cells recruitment and promotes bile duct ligation-induced liver fibrosis.

Liver fibrosis is a course of chronic liver dysfunction, can develop into cirrhosis and hepatocellular carcinoma. Inflammatory insult owing to pathogenic factors plays a crucial role in the pathogenesis of liver fibrosis. Indoleamine 2,3-dioxygenase 1 (IDO1) can affect the infiltration of immune cells in many pathology processes of diseases, but its role in liver fibrosis has not been elucidated completely. Here, the markedly elevated protein IDO1 in livers was identified, and dendritic cells (DCs) immune-phenotypes were significantly altered after BDL challenge. A distinct hepatic population of CD11c+DCs was decreased and presented an immature immune-phenotype, reflected by lower expression levels of co-stimulatory molecules (CD40, MHCII). Frequencies of CD11c+CD80+, CD11c+CD86+, CD11c+MHCII+, and CD11c+CD40+ cells in splenic leukocytes were reduced significantly. Notably, IDO1 overexpression inhibited hepatic, splenic CD11c+DCs maturation, mature DCs-mediated T-cell proliferation and worsened liver fibrosis, whereas above pathological phenomena were reversed in IDO1-/- mice. Our data demonstrate that IDO1 affects the process of immune cells recruitment via inhibiting DCs maturation and subsequent T cells proliferation, resulting in the promotion of hepatic fibrosis. Thus, amelioration of immune responses in hepatic and splenic microenvironment by targeting IDO1 might be essential for the therapeutic effects on liver fibrosis.

Therapeutic effect of uridine phosphorylase 1 (UPP1) inhibitor on liver fibrosis in vitro and in vivo.

Potassium 5-cyano-4-methyl-6-oxo-1,6-dihydropyridine-2-olate (CPBMF65) is a potent inhibitor of the uridine phosphorylase 1 (UPP1) enzyme. Its non-ionized analog has already demonstrated biological properties by reducing adverse effects caused by the chemotherapeutic 5-fluorouracil (5-FU). In addition, it has been demonstrated that uridine inhibits inflammation and fibrosis in bleomycin lung injury, decreasing collagen production. The purpose of this study was to investigate the in vitro and in vivo effects of CPBMF65 on activated hepatic stellate cells (HSC) and on carbon tetrachloride-induced liver fibrosis in mice. After incubation with CPBMF65, decreased cell proliferation and phenotype reversion were observed in vitro. In addition, CPBMF65 promoted a protective effect on tetrachloride-induced liver fibrosis in mice, demonstrated by its antifibrotic and anti-inflammatory actions. The results of the present study indicate that the UPP1 inhibitor (CPBMF65) may have potential as a novel therapeutic agent for the treatment of liver fibrosis.

Histone deacetylase 8 inhibition alleviates cholestatic liver injury and fibrosis.

Cholestasis is a pathological condition involving blockage of bile flow that results in hepatotoxicity, inflammation, and fibrosis. Although recent studies have shown that histone deacetylases (HDACs) are involved in the progression of fibrosis in various organs, the role of HDAC8 on liver fibrosis has until now remained unexplored. This study presents a newly-synthesized, selective HDAC8 inhibitor SPA3014 composed of a vinyl disulfide-sulfoxide core, and evaluates its therapeutic efficacy against cholestatic liver injury and fibrosis in bile duct-ligated (BDL) mice. We first observed the increase in HDAC8 protein levels in mice with BDL and patients with cholestatic liver disease. Mice with BDL that were pretreated with SPA3014 had lower liver damage and fibrosis, based on gross examination, histopathologic findings, and biochemical analyses, than did vehicle-treated mice. Studies with LX-2 human hepatic stellate cells showed that SPA3014 exerted protective effects by inhibiting TGF-ß-mediated activation of MAPK-Smad2/3 and JAK2-STAT3 pathways and by upregulating PPARγ expression. Overall, these results strongly suggest that HDAC8 inhibition constitutes a new therapeutic strategy for treatment of cholestatic liver injury.

Tyrosine kinase inhibitor neratinib attenuates liver fibrosis by targeting activated hepatic stellate cells.

Liver fibrosis, a common outcome of chronic liver disease characterized by excessive accumulation of extracellular matrix (ECM), is a leading cause of mortality worldwide. The tyrosine kinase inhibitor neratinib is a human epidermal growth factor receptor 2 (HER2) inhibitor approved by the FDA for HER2-positive breast cancer treatment; however, it has not yet been evaluated for liver fibrosis treatment. We elucidated the anti-fibrotic effects of neratinib in hepatic stellate cells (HSCs) and in vivo models of CCl4-induced liver fibrosis. HSC activation is a key step in liver fibrogenesis and has a crucial role in collagen deposition, as it is primarily responsible for excessive ECM production. The effect of neratinib on HSC was evaluated in transforming growth factor (TGF-ß)-incubated LX-2 cells and culture-activated primary human HSCs. In vivo study results indicated that neratinib inhibited the inflammatory response, HSC differentiation, and collagen accumulation induced by CCl4. Moreover, the anti-fibrotic effects of neratinib were not associated with the HER2 signaling pathways. Neratinib inhibited FGF2 expression in activated HSCs and serum FGF2 level in the model, suggesting that neratinib possessed therapeutic potency against liver fibrosis and the potential for application against other fibrotic diseases.