Non-invasive candidate protein signature predicts hepatic venous pressure gradient reduction in cirrhotic patients after sustained virologic response.

BACKGROUND AND AIMS: A reduction in hepatic venous pressure gradient (HVPG) is the most accurate marker for assessing the severity of portal hypertension and the effectiveness of intervention treatments. This study aimed to evaluate the prognostic potential of blood-based proteomic biomarkers in predicting HVPG response amongst cirrhotic patients with portal hypertension due to Hepatitis C virus (HCV) and had achieved sustained virologic response (SVR). METHODS: The study comprised 59 patients from two cohorts. Patients underwent paired HVPG (pretreatment and after SVR), liver stiffness (LSM), and enhanced liver fibrosis scores (ELF) measurements, as well as proteomics-based profiling on serum samples using SomaScan® at baseline (BL) and after SVR (EOS). Machine learning with feature selection (Caret, Random Forest and RPART) methods were performed to determine the proteins capable of classifying HVPG responders. Model performance was evaluated using AUROC (pROC R package). RESULTS: Patients were stratified by a change in HVPG (EOS vs. BL) into responders (greater than 20% decline in HVPG from BL, or <10 mmHg at EOS with >10 mmHg at BL) and non-responders. LSM and ELF decreased markedly after SVR but did not correlate with HVPG response. SomaScan (SomaLogic, Inc., Boulder, CO) analysis revealed a substantial shift in the peripheral proteome composition, reflected by 82 significantly differentially abundant proteins. Twelve proteins accurately distinguished responders from non-responders, with an AUROC of .86, sensitivity of 83%, specificity of 83%, accuracy of 83%, PPV of 83%, and NPV of 83%. CONCLUSIONS: A combined non-invasive soluble protein signature was identified, capable of accurately predicting HVPG response in HCV liver cirrhosis patients after achieving SVR.

Licogliflozin for nonalcoholic steatohepatitis: a randomized, double-blind, placebo-controlled, phase 2a study.

Nonalcoholic steatohepatitis (NASH) is a common chronic liver disease that may advance to fibrosis and lead to mortality; however, no pharmacotherapy is currently available. We tested the hypothesis that inhibition of both the sodium-glucose cotransporters 1 and 2 with licogliflozin would lead to improvement in NASH. A total of 107 patients with phenotypic or histologic NASH were randomized (1:2:2) to receive oral administration of either placebo (n = 21), licogliflozin 30 mg (n = 43) or 150 mg (n = 43) once daily for 12 weeks. Licogliflozin 150 mg showed a significant 32% (80% confidence interval (CI): 21-43%; P = 0.002) placebo-adjusted reduction in serum alanine aminotransferase after 12 weeks of treatment, the primary endpoint of the study. However, the 30 mg dose of licogliflozin did not meet the primary endpoint (placebo-adjusted reduction 21% (80% CI: 7-32%; P = 0.061)). Diarrhea occurred in 77% (33 of 43), 49% (21 of 43) and 43% (9 of 21) of patients treated with licogliflozin 150 mg, 30 mg and placebo, respectively, which was mostly mild in severity. No other major safety concerns were identified. Treatment with 150 mg licogliflozin led to reductions in serum alanine aminotransferase in patients with NASH. Studies of longer duration and in combination with drugs that have different mechanisms of action are needed to validate these findings and to define a role of licogliflozin as a therapeutic option for NASH. ClinicalTrials.gov identifier: NCT03205150.

ADAMTSL2 protein and a soluble biomarker signature identify at-risk non-alcoholic steatohepatitis and fibrosis in adults with NAFLD.

BACKGROUND & AIMS: Identifying fibrosis in non-alcoholic fatty liver disease (NAFLD) is essential to predict liver-related outcomes and guide treatment decisions. A protein-based signature of fibrosis could serve as a valuable, non-invasive diagnostic tool. This study sought to identify circulating proteins associated with fibrosis in NAFLD. METHODS: We used aptamer-based proteomics to measure 4,783 proteins in 2 cohorts (Cohort A and B). Targeted, quantitative assays coupling aptamer-based protein pull down and mass spectrometry (SPMS) validated the profiling results in a bariatric and NAFLD cohort (Cohort C and D, respectively). Generalized linear modeling-logistic regression assessed the ability of candidate proteins to classify fibrosis. RESULTS: From the multiplex profiling, 16 proteins differed significantly by fibrosis in cohorts A (n = 62) and B (n = 98). Quantitative and robust SPMS assays were developed for 8 proteins and validated in Cohorts C (n = 71) and D (n = 84). The A disintegrin and metalloproteinase with thrombospondin motifs like 2 (ADAMTSL2) protein accurately distinguished non-alcoholic fatty liver (NAFL)/non-alcoholic steatohepatitis (NASH) with fibrosis stage 0-1 (F0-1) from at-risk NASH with fibrosis stage 2-4, with AUROCs of 0.83 and 0.86 in Cohorts C and D, respectively, and from NASH with significant fibrosis (F2-3), with AUROCs of 0.80 and 0.83 in Cohorts C and D, respectively. An 8-protein panel distinguished NAFL/NASH F0-1 from at-risk NASH (AUROCs 0.90 and 0.87 in Cohort C and D, respectively) and NASH F2-3 (AUROCs 0.89 and 0.83 in Cohorts C and D, respectively). The 8-protein panel and ADAMTSL2 protein had superior performance to the NAFLD fibrosis score and fibrosis-4 score. CONCLUSION: The ADAMTSL2 protein and an 8-protein soluble biomarker panel are highly associated with at-risk NASH and significant fibrosis; they exhibited superior diagnostic performance compared to standard of care fibrosis scores. LAY SUMMARY: Non-alcoholic fatty liver disease (NAFLD) is one of the most common causes of liver disease worldwide. Diagnosing NAFLD and identifying fibrosis (scarring of the liver) currently requires a liver biopsy. Our study identified novel proteins found in the blood which may identify fibrosis without the need for a liver biopsy.

The Genetic Architecture of Carbon Tetrachloride-Induced Liver Fibrosis in Mice.

BACKGROUND & AIMS: Liver fibrosis is a multifactorial trait that develops in response to chronic liver injury. Our aim was to characterize the genetic architecture of carbon tetrachloride (CCl4)-induced liver fibrosis using the Hybrid Mouse Diversity Panel, a panel of more than 100 genetically distinct mouse strains optimized for genome-wide association studies and systems genetics. METHODS: Chronic liver injury was induced by CCl4 injections twice weekly for 6 weeks. Four hundred thirty-seven mice received CCl4 and 256 received vehicle, after which animals were euthanized for liver histology and gene expression. Using automated digital image analysis, we quantified fibrosis as the collagen proportionate area of the whole section, excluding normal collagen. RESULTS: We discovered broad variation in fibrosis among the Hybrid Mouse Diversity Panel strains, demonstrating a significant genetic influence. Genome-wide association analyses revealed significant and suggestive loci underlying susceptibility to fibrosis, some of which overlapped with loci identified in mouse crosses and human population studies. Liver global gene expression was assessed by RNA sequencing across the strains, and candidate genes were identified using differential expression and expression quantitative trait locus analyses. Gene set enrichment analyses identified the underlying pathways, of which stellate cell involvement was prominent, and coexpression network modeling identified modules associated with fibrosis. CONCLUSIONS: Our results provide a rich resource for the design of experiments to understand mechanisms underlying fibrosis and for rational strain selection when testing antifibrotic drugs.

Clinical translation of liver regeneration therapies: A conceptual road map.

The increasing incidence of severe liver diseases worldwide has resulted in a high demand for curative liver transplantation. Unfortunately, the need for transplants by far eclipses the availability of suitable grafts leaving many waitlisted patients to face liver failure and often death. Routine use of smaller grafts (for example left lobes, split livers) from living or deceased donors could increase the number of life-saving transplants but is often limited by the graft versus recipient weight ratio defining the safety margins that minimize the risk of small for size syndrome (SFSS). SFSS is a severe complication characterized by failure of a small liver graft to regenerate and occurs when a donor graft is insufficient to meet the metabolic demand of the recipient, leading to liver failure as a result of insufficient liver mass. SFSS is not limited to transplantation but can also occur in the setting of hepatic surgical resections, where life-saving large resections of tumors may be limited by concerns of post-surgical liver failure. There are, as yet no available pro-regenerative therapies to enable liver regrowth and thus prevent SFSS. However, there is optimism around targeting factors and pathways that have been identified as regulators of liver regeneration to induce regrowth in vivo and ex vivo for clinical use. In this commentary, we propose a roadmap for developing such pro-regenerative therapy and for bringing it into the clinic. We summarize the clinical indications, preclinical models, pro-regenerative pathways and safety considerations necessary for developing such a drug.

Epigenetic Compensation Promotes Liver Regeneration.

Two major functions of the epigenome are to regulate gene expression and to suppress transposons. It is unclear how these functions are balanced during physiological challenges requiring tissue regeneration, where exquisite coordination of gene expression is essential. Transcriptomic analysis of seven time points following partial hepatectomy identified the epigenetic regulator UHRF1, which is essential for DNA methylation, as dynamically expressed during liver regeneration in mice. UHRF1 deletion in hepatocytes (Uhrf1HepKO) caused genome-wide DNA hypomethylation but, surprisingly, had no measurable effect on gene or transposon expression or liver homeostasis. Partial hepatectomy of Uhrf1HepKO livers resulted in early and sustained activation of proregenerative genes and enhanced liver regeneration. This was attributed to redistribution of H3K27me3 from promoters to transposons, effectively silencing them and, consequently, alleviating repression of liver regeneration genes, priming them for expression in Uhrf1HepKO livers. Thus, epigenetic compensation safeguards the genome against transposon activation, indirectly affecting gene regulation.

Peripartum Maternal Hepatitis B Care in a US Nationwide Data Set.

BACKGROUND: Hepatitis B virus (HBV) screening during pregnancy is standard of care to prevent vertical transmission to infants, yet the mothers themselves may not receive appropriate follow-up. GOALS: Using a national database, we sought to determine rates of maternal peripartum follow-up with a HBV specialist and identify factors associated with a lack of follow-up. MATERIALS AND METHODS: We identified women who delivered in 2000 to 2012 and were diagnosed with HBV according to International Classification of Diseases-9 codes using a national database (Optum) derived from commercial insurance claims with ∼46 million members ages 0 to 64 in all 50 states. Our primary outcome was follow-up during or after pregnancy with a HBV specialist (gastroenterology/infectious diseases). RESULTS: The prevalence of HBV was 0.27% (2558/959,747 pregnancies), and median follow-up was 45 months. Only 21% of women had peripartum HBV specialist follow-up. On multivariable regression, predictors of peripartum follow-up at 1-year included younger age [odds ratio (OR), 0.97/y; 95% confidence interval (CI), 0.94, 0.99], Asian race/ethnicity (OR, 1.56 vs. white; 95% CI, 1.13, 2.17), and residing in the Northeast (OR, 1.70; 95% CI, 1.09, 2.66) and Midwest (OR, 1.73; 95% CI, 1.07, 2.81) versus West. Predictors of testing for HBV DNA and alanine aminotransferase at 1 year included Asian race (OR, 1.72; 95% CI, 1.23, 2.41), a primary care physician visit within 2 years of delivery (OR, 1.63; 95% CI, 1.19, 2.22), and peripartum HBV specialist follow-up within 1 year (OR, 15.68; 95% CI, 11.38, 21.60). CONCLUSIONS: Maternal HBV specialist follow-up rates were extremely low in this large, diverse cohort representing all United States regions. Referral to a HBV specialist was the strongest predictor of appropriate postpartum HBV laboratory testing. Follow-up rates may be even lower in uninsured populations.

Peripartum Care for Mothers Diagnosed with Hepatitis B During Pregnancy: A Survey of Provider Practices.

Objectives Hepatitis B (HBV) remains a significant public health burden, despite effective therapy. Routine HBV screening is recommended during pregnancy to reduce the risk of vertical transmission, but the rates of follow-up care peri-partum are low. The aim of this study was to evaluate physician practices and knowledge regarding HBV in women diagnosed perinatally. Methods A survey was distributed to obstetricians and midwives within the Partners HealthCare system at Brigham and Women's Hospital and Massachusetts General Hospital. Results Of 118 survey respondents (response rate 56%), 97% reported that they always tested for hepatitis B, and 77% referred new diagnoses of HBV during pregnancy to a HBV specialist for further care. Only 10% of respondents reported that there was formal referral mechanism in place to facilitate follow-up care for mothers diagnosed with hepatitis B infection. 91% of survey respondents selected hepatitis B surface antigen as the correct screening test, and 76% selected hepatitis B immune globulin with vaccination for the newborn as the correct prophylaxis regimen. Only 40 and 51% of respondents accurately identified serologies that were consistent with acute and chronic infection, respectively. Conclusions for Practice Routine screening for HBV in this population presents an important opportunity to identify cases and to reduce the public health burden of this disease. Providers were somewhat knowledgeable about HBV, but the lack of formal referral mechanism may explain why HBV follow-up is suboptimal in this healthcare system. Supplemental provider education and formal linkage to care programs may increase rates of follow-up HBV care.

Liver health in adults with Fontan circulation: A multicenter cross-sectional study.

OBJECTIVES: Liver disease is an important contributor to morbidity and mortality in patients after Fontan surgery. There has been no large-scale survey of liver health in this population. We sought to explore the prevalence and predictors of liver disease in a multicenter cohort of adults with Fontan physiology. METHODS: Subjects were recruited from 6 adult congenital heart centers. Demographics; clinical history; and laboratory, imaging, and histopathology data were obtained. RESULTS: Of 241 subjects (median age 25.8 years [11.8-59.4], median time since Fontan 20.3 years [5.4-34.5]), more than 94% of those who underwent testing (208 of 221) had at least 1 abnormal liver-related finding. All hepatic imaging (n = 54) and liver histology (n = 68) was abnormal. Subjects with abnormal laboratory values had higher sinusoidal fibrosis stage (2 vs 1, P = .007) and higher portal fibrosis stage (3 vs 1, P = .003) compared with those with all normal values. Low albumin correlated with lower sinusoidal fibrosis stage (1 vs 2; P = .02) and portal fibrosis stage (0 vs 3, P = .002); no other liver studies correlated with fibrosis. Regenerative nodules were seen on 33% of histology specimens. CONCLUSIONS: Regardless of modality, findings of liver disease are common among adults with Fontan circulation, even those appearing clinically well. Cirrhosis is present in up to one-third of subjects. Correlations between hepatic fibrosis stage and clinical history or findings on noninvasive testing are few. Further research is needed to identify patients at risk for more severe liver disease and to determine the best methods for assessing liver health in this population.

Predictive value of biomarkers of hepatic fibrosis in adult Fontan patients.

BACKGROUND: Hepatic fibrosis is highly prevalent in individuals with Fontan circulation. FibroSure (LabCorp, Burlington, NC) and hyaluronic acid (HA) have been validated for assessment of hepatic fibrosis in several forms of liver disease. We sought to determine whether these tests could identify Fontan patients with advanced hepatic fibrosis or cirrhosis. METHODS: Subjects who had liver biopsy and FibroSure or HA testing within 6 months of biopsy were identified from the Alliance for Adult Research in Congenital Cardiology Fontan Liver Health study. Biopsy specimens were scored for degree of sinusoidal and portal fibrosis on a 3- and 5-point scale, respectively. Histologic findings were correlated with FibroSure and HA results. RESULTS: The study included 27 subjects. Median age was 26.8 years (range, 17.4-59.8 years), and the median time since the Fontan surgery was 20.4 years (range, 12.0-31.3 years). FibroSure scores were elevated (>0.21) in 21 of 23 subjects (91%), and the scores for 3 (13%) suggested cirrhosis (>0.74). HA suggested cirrhosis (>46 ng/mL) in 3 of 17 subjects (18%). One subject died during the collection period. Eleven of 26 subjects (42%) had 4/5 or 5/5 portal fibrosis, consistent with cirrhosis; 17 (63%) had 3/3 sinusoidal fibrosis involving >66% of sinusoids. The FibroSure score and HA levels did not correlate with the degree of hepatic fibrosis and did not predict cirrhosis. CONCLUSIONS: Abnormal biomarkers of hepatic fibrosis and specimen-proven hepatic fibrosis are common in adults with Fontan circulation. However, FibroSure and HA do not accurately predict the degree of histologic hepatic fibrosis. Further studies are needed to guide strategies for surveillance of liver disease in this population.

Postpartum Laboratory Follow-up in Women With Hepatitis B in Massachusetts From 2007 to 2012.

GOALS: To determine postpartum hepatitis B virus (HBV) laboratory testing rates and identify factors associated with a lack of follow-up testing in Massachusetts. BACKGROUND: Screening for HBV infection in pregnant women is standard of care. Guidelines recommend that patients with chronic HBV have ongoing care and laboratory testing, but little is known about postpartum maternal HBV care outcomes. STUDY: We conducted a retrospective cohort study using Massachusetts Virtual Epidemiologic Network, an electronic public health surveillance system maintained by the Massachusetts Department of Public Health. We identified women who tested hepatitis B surface antigen positive during their first reported (index) pregnancy in Massachusetts from 2007 to 2012 and measured HBV-related laboratory tests reported to Massachusetts Department of Public Health during and after pregnancy. RESULTS: We identified 983 hepatitis B surface antigen positive pregnant women. Half (492/983) did not have evidence of additional postpartum HBV laboratory testing following their index pregnancy. Women who had postpartum laboratory tests reported were younger [mean age (SD): 29 (5.3) vs. 31 (5.5) y, P=0.0001] and more likely to have >1 pregnancy during the study period (41% vs. 1%, P<0.0001). There were no differences in race, ethnicity, and US born status. On multivariable logistic regression, older age predicted a lower likelihood of having postpartum laboratory testing (odds ratio, 0.77; 95% confidence interval, 0.70-0.90). CONCLUSIONS: Postpartum maternal HBV follow-up laboratory testing occurred in only half of Massachusetts women and did not vary by race, ethnicity, or US born status. Our results were limited to a single state surveillance database, which likely underestimates the number of tests ordered.

The RSPO-LGR4/5-ZNRF3/RNF43 module controls liver zonation and size.

LGR4/5 receptors and their cognate RSPO ligands potentiate Wnt/ß-catenin signalling and promote proliferation and tissue homeostasis in epithelial stem cell compartments. In the liver, metabolic zonation requires a Wnt/ß-catenin signalling gradient, but the instructive mechanism controlling its spatiotemporal regulation is not known. We have now identified the RSPO-LGR4/5-ZNRF3/RNF43 module as a master regulator of Wnt/ß-catenin-mediated metabolic liver zonation. Liver-specific LGR4/5 loss of function (LOF) or RSPO blockade disrupted hepatic Wnt/ß-catenin signalling and zonation. Conversely, pathway activation in ZNRF3/RNF43 LOF mice or with recombinant RSPO1 protein expanded the hepatic Wnt/ß-catenin signalling gradient in a reversible and LGR4/5-dependent manner. Recombinant RSPO1 protein increased liver size and improved liver regeneration, whereas LGR4/5 LOF caused the opposite effects, resulting in hypoplastic livers. Furthermore, we show that LGR4(+) hepatocytes throughout the lobule contribute to liver homeostasis without zonal dominance. Taken together, our results indicate that the RSPO-LGR4/5-ZNRF3/RNF43 module controls metabolic liver zonation and is a hepatic growth/size rheostat during development, homeostasis and regeneration.

Targeted disruption of fibrinogen like protein-1 accelerates hepatocellular carcinoma development.

Fibrinogen like protein-1 (Fgl1) is a predominantly liver expressed protein that has been implicated as both a hepatoprotectant and a hepatocyte mitogen. Fgl1 expression is decreased in hepatocellular carcinoma (HCC) and its loss correlates with a poorly differentiated phenotype. To better elucidate the role of Fgl1 in hepatocarcinogenesis, we treated mice wild type or null for Fgl1 with diethyl nitrosamine and monitored for incidence of hepatocellular cancer. We find that mice lacking Fgl1 develop HCC at more than twice the rate of wild type mice. We show that hepatocellular cancers from Fgl1 null mice are molecularly distinct from those of the wild type mice. In tumors from Fgl1 null mice there is enhanced activation of Akt and downstream targets of the mammalian target of rapamycin (mTOR). In addition, there is paradoxical up regulation of putative hepatocellular cancer tumor suppressors; tripartite motif-containing protein 35 (Trim35) and tumor necrosis factor super family 10b (Tnfrsf10b). Taken together, these findings suggest that Fgl1 acts as a tumor suppressor in hepatocellular cancer through an Akt dependent mechanism and supports its role as a potential therapeutic target in HCC.

Portal and centrilobular hepatic fibrosis in Fontan circulation and clinical outcomes.

BACKGROUND: The Fontan operation redirects venous blood flow directly to the pulmonary circulation in subjects with single ventricle anatomy. Congestive hepatopathy and cirrhosis have been described in subjects with Fontan circulation, but the prevalence of and predictors for liver disease remain unknown. METHODS: We performed a retrospective study of liver histopathology in Fontan subjects who had liver biopsy or autopsy. All specimens were graded using a pre-determined protocol. Additional data were collected through chart review. Among 68 subjects, specimens were obtained at a median age of 23.2 years (range 5.0 to 52.7 years). Median time since Fontan was 18.1 years (range 1.2 to 32.7 years). RESULTS: Centrilobular fibrosis was seen in every specimen, with 41.2% showing Grade 4 centrilobular fibrosis. Portal fibrosis was seen in 82.3% of specimens, with 14.7% showing cirrhosis. Megamitochondria were seen in 58.8% of specimens. Centrilobular fibrosis grade was greater in those with a dominant left or right ventricle than in those with a combined right and left systemic ventricle (p = 0.008). Portal fibrosis grade correlated with alkaline phosphatase (p = 0.04) and mode of biopsy (p = 0.02). Neither centrilobular fibrosis nor portal fibrosis grade was predictive of transplant-free survival or overall survival. CONCLUSIONS: Individuals with Fontan physiology have a high prevalence of hepatic fibrosis. Signs and symptoms of liver disease did not predict histopathologic findings. Few risk factors for advanced disease were identified. Histopathology findings did not predict transplant-free survival. The role of liver biopsy in this population remains uncertain.

Postpartum care for mothers diagnosed with hepatitis B during pregnancy.

OBJECTIVE: We sought to determine rates of maternal postpartum hepatitis B virus (HBV) follow-up with a HBV specialist and identify factors associated with poor follow-up, as prior research has focused on infant outcomes and not maternal care. STUDY DESIGN: We conducted a retrospective review of data from Partners HealthCare system, the largest health care system in Massachusetts, and identified women with chronic HBV who delivered from 2002 through 2012. RESULTS: We identified 291 women (mean age 31.5 years, 51% Asian) with incident HBV during pregnancy. In all, 47% had postpartum follow-up with a HBV specialist, but only 19% also had appropriate laboratory tests (hepatitis B e antigen [HBeAg], hepatitis B e antibody, HBV DNA, and ALT) within 1 year of their HBV diagnosis. Mothers with HBV follow-up were more likely to have a primary care physician (PCP) within the Partners HealthCare system (66% vs 38%, P < .0001), a positive HBeAg (20% vs 8%, P = .004), and elevated AST values (17% vs 8%, P = .02). On multivariable logistic regression analysis, a mother who had a PCP (odds ratio, 2.50; 95% confidence interval, 1.37-4.59) or positive HBeAg (odds ratio, 4.45; 95% confidence interval, 1.64-12.06) had a greater likelihood of having HBV follow-up. CONCLUSION: Only 19% of HBV-infected mothers met care guidelines 1 year after being diagnosed with HBV. Inadequate postpartum HBV care affects women of all races/ethnicities. Women who had a PCP as well as those who were HBeAg positive were more likely to be referred for postpartum follow-up with a HBV specialist, suggesting that providers might be referring patients when they perceive HBV to be more serious or complex.

Mice with hepatocyte-specific deficiency of type 3 deiodinase have intact liver regeneration and accelerated recovery from nonthyroidal illness after toxin-induced hepatonecrosis.

Type 3 deiodinase (D3), the physiologic inactivator of thyroid hormones, is induced during tissue injury and regeneration. This has led to the hypotheses that D3 impacts injury tolerance by reducing local T3 signaling and contributes to the fall in serum triiodothyronine (T3) observed in up to 75% of sick patients (termed the low T3 syndrome). Here we show that a novel mutant mouse with hepatocyte-specific D3 deficiency has normal local responses to toxin-induced hepatonecrosis, including normal degrees of tissue necrosis and intact regeneration, but accelerated systemic recovery from illness-induced hypothyroxinemia and hypotriiodothyroninemia, demonstrating that peripheral D3 expression is a key modulator of the low T3 syndrome.

UHRF1 overexpression drives DNA hypomethylation and hepatocellular carcinoma.

Ubiquitin-like with PHD and RING finger domains 1 (UHRF1) is an essential regulator of DNA methylation that is highly expressed in many cancers. Here, we use transgenic zebrafish, cultured cells, and human tumors to demonstrate that UHRF1 is an oncogene. UHRF1 overexpression in zebrafish hepatocytes destabilizes and delocalizes Dnmt1 and causes DNA hypomethylation and Tp53-mediated senescence. Hepatocellular carcinoma (HCC) emerges when senescence is bypassed. tp53 mutation both alleviates senescence and accelerates tumor onset. Human HCCs recapitulate this paradigm, as UHRF1 overexpression defines a subclass of aggressive HCCs characterized by genomic instability, TP53 mutation, and abrogation of the TP53-mediated senescence program. We propose that UHRF1 overexpression is a mechanism underlying DNA hypomethylation in cancer cells and that senescence is a primary means of restricting tumorigenesis due to epigenetic disruption.

Transient elastography may identify Fontan patients with unfavorable hemodynamics and advanced hepatic fibrosis.

BACKGROUND: Transient elastography (TE) offers a noninvasive correlate with the degree of hepatic fibrosis. However, factors other than fibrosis affect liver stiffness. We sought to determine whether hepatic congestion related to hemodynamics in Fontan circulation influences liver stiffness measurement (LSM) assessed by TE. METHODS: We studied 45 subjects with Fontan circulation undergoing cardiac catheterization with or without simultaneous liver biopsy. Subjects underwent TE within 5 days before catheterization. Clinical history, hemodynamic and biopsy data, and hepatic biomarkers were collected. Five subjects who had previously undergone liver biopsy and TE were also included. RESULTS: Median age was 13.1 years (range 2.4-57.8); median time since Fontan was 9.9 years (range 0.1-32.5). No subject had known hepatitis C. Mean LSM for the entire cohort was 21.4 ± 10.8 kPa. Univariate regression analysis using LSM as a continuous outcome variable shows significant correlations with age (R = 0.35, P = .01), time since Fontan (R = 0.41, P = .003), Fontan pressure (R = 0.31, P = .04), cardiac index (R = 0.33, P = .03), pulmonary vascular resistance (R = 0.34, P = .03), systemic arterial oxygen saturation (R = 0.31, P = .04), and platelet count (R = 0.29, P = .05). On multiple regression analysis, Fontan pressure (ß = 0.901, P = .03) and cardiac index (ß = 2.703, P = .02) were significant predictors of LSM with overall model R(2) = 0.206. Univariate analysis shows LSM to be associated with more severe centrilobular fibrosis (P = .05). CONCLUSIONS: Higher LSM is associated with unfavorable Fontan hemodynamics and advanced centrilobular hepatic fibrosis. TE may be a useful tool for identifying Fontan patients who warrant invasive testing.

Phosphatidylcholine transfer protein interacts with thioesterase superfamily member 2 to attenuate insulin signaling.

Phosphatidylcholine transfer protein (PC-TP) is a phospholipid-binding protein that is enriched in liver and that interacts with thioesterase superfamily member 2 (THEM2). Mice lacking either protein exhibit improved hepatic glucose homeostasis and are resistant to diet-induced diabetes. Insulin receptor substrate 2 (IRS2) and mammalian target of rapamycin complex 1 (mTORC1) are key effectors of insulin signaling, which is attenuated in diabetes. We found that PC-TP inhibited IRS2, as evidenced by insulin-independent IRS2 activation after knockdown, genetic ablation, or chemical inhibition of PC-TP. In addition, IRS2 was activated after knockdown of THEM2, providing support for a role for the interaction of PC-TP with THEM2 in suppressing insulin signaling. Additionally, we showed that PC-TP bound to tuberous sclerosis complex 2 (TSC2) and stabilized the components of the TSC1-TSC2 complex, which functions to inhibit mTORC1. Preventing phosphatidylcholine from binding to PC-TP disrupted interactions of PC-TP with THEM2 and TSC2, and disruption of the PC-TP-THEM2 complex was associated with increased activation of both IRS2 and mTORC1. In livers of mice with genetic ablation of PC-TP or that had been treated with a PC-TP inhibitor, steady-state amounts of IRS2 were increased, whereas those of TSC2 were decreased. These findings reveal a phospholipid-dependent mechanism that suppresses insulin signaling downstream of its receptor.