Exploring the impact of the PNPLA3 I148M variant on primary human hepatic stellate cells using 3D extracellular matrix models.

BACKGROUND & AIMS: The PNPLA3 rs738409 C>G (encoding for I148M) variant is a risk locus for the fibrogenic progression of chronic liver diseases, a process driven by hepatic stellate cells (HSCs). We investigated how the PNPLA3 I148M variant affects HSC biology using transcriptomic data and validated findings in 3D-culture models. METHODS: RNA sequencing was performed on 2D-cultured primary human HSCs and liver biopsies of individuals with obesity, genotyped for the PNPLA3 I148M variant. Data were validated in wild-type (WT) or PNPLA3 I148M variant-carrying HSCs cultured on 3D extracellular matrix (ECM) scaffolds from human healthy and cirrhotic livers, with/without TGFB1 or cytosporone B (Csn-B) treatment. RESULTS: Transcriptomic analyses of liver biopsies and HSCs highlighted shared PNPLA3 I148M-driven dysregulated pathways related to mitochondrial function, antioxidant response, ECM remodelling and TGFB1 signalling. Analogous pathways were dysregulated in WT/PNPLA3-I148M HSCs cultured in 3D liver scaffolds. Mitochondrial dysfunction in PNPLA3-I148M cells was linked to respiratory chain complex IV insufficiency. Antioxidant capacity was lower in PNPLA3-I148M HSCs, while reactive oxygen species secretion was increased in PNPLA3-I148M HSCs and higher in bioengineered cirrhotic vs. healthy scaffolds. TGFB1 signalling followed the same trend. In PNPLA3-I148M cells, expression and activation of the endogenous TGFB1 inhibitor NR4A1 were decreased: treatment with the Csn-B agonist increased total NR4A1 in HSCs cultured in healthy but not in cirrhotic 3D scaffolds. NR4A1 regulation by TGFB1/Csn-B was linked to Akt signalling in PNPLA3-WT HSCs and to Erk signalling in PNPLA3-I148M HSCs. CONCLUSION: HSCs carrying the PNPLA3 I148M variant have impaired mitochondrial function, antioxidant responses, and increased TGFB1 signalling, which dampens antifibrotic NR4A1 activity. These features are exacerbated by cirrhotic ECM, highlighting the dual impact of the PNPLA3 I148M variant and the fibrotic microenvironment in progressive chronic liver diseases. IMPACT AND IMPLICATIONS: Hepatic stellate cells (HSCs) play a key role in the fibrogenic process associated with chronic liver disease. The PNPLA3 genetic mutation has been linked with increased risk of fibrogenesis, but its role in HSCs requires further investigation. Here, by using comparative transcriptomics and a novel 3D in vitro model, we demonstrate the impact of the PNPLA3 genetic mutation on primary human HSCs' behaviour, and we show that it affects the cell's mitochondrial function and antioxidant response, as well as the antifibrotic gene NR4A1. Our publicly available transcriptomic data, 3D platform and our findings on NR4A1 could facilitate the discovery of targets to develop more effective treatments for chronic liver diseases.

The human liver microenvironment shapes the homing and function of CD4+ T-cell populations.

OBJECTIVE: Tissue-resident memory T cells (TRM) are vital immune sentinels that provide protective immunity. While hepatic CD8+ TRM have been well described, little is known about the location, phenotype and function of CD4+ TRM. DESIGN: We used multiparametric flow cytometry, histological assessment and novel human tissue coculture systems to interrogate the ex vivo phenotype, function and generation of the intrahepatic CD4+ T-cell compartment. We also used leukocytes isolated from human leukocyte antigen (HLA)-disparate liver allografts to assess long-term retention. RESULTS: Hepatic CD4+ T cells were delineated into three distinct populations based on CD69 expression: CD69-, CD69INT and CD69HI. CD69HICD4+ cells were identified as tissue-resident CD4+ T cells on the basis of their exclusion from the circulation, phenotypical profile (CXCR6+CD49a+S1PR1-PD-1+) and long-term persistence within the pool of donor-derived leukcoocytes in HLA-disparate liver allografts. CD69HICD4+ T cells produced robust type 1 polyfunctional cytokine responses on stimulation. Conversely, CD69INTCD4+ T cells represented a more heterogenous population containing cells with a more activated phenotype, a distinct chemokine receptor profile (CX3CR1+CXCR3+CXCR1+) and a bias towards interleukin-4 production. While CD69INTCD4+ T cells could be found in the circulation and lymph nodes, these cells also formed part of the long-term resident pool, persisting in HLA-mismatched allografts. Notably, frequencies of CD69INTCD4+ T cells correlated with necroinflammatory scores in chronic hepatitis B infection. Finally, we demonstrated that interaction with hepatic epithelia was sufficient to generate CD69INTCD4+ T cells, while additional signals from the liver microenvironment were required to generate liver-resident CD69HICD4+ T cells. CONCLUSIONS: High and intermediate CD69 expressions mark human hepatic CD4+ TRM and a novel functionally distinct recirculating population, respectively, both shaped by the liver microenvironment to achieve diverse immunosurveillance.

Comparison of point-shear wave elastography (ElastPQ) and transient elastography (FibroScan) for liver fibrosis staging in patients with non-alcoholic fatty liver disease.

BACKGROUND AND AIMS: ElastPQ is a point shear wave elastography technique used to non-invasively assess liver fibrosis. We compared liver stiffness measurements (LSM) by ElastPQ and fibroscan transient elastography (F-TE) in a cohort of patients with non-alcoholic fatty liver disease (NAFLD). We further evaluated the performance of ElastPQ in a subgroup of patients with available liver histology. MATERIALS AND METHODS: We included patients with NAFLD who presented in a dedicated multidisciplinary clinic. Anthropometric parameters, blood tests and elastography measurements were obtained using F-TE and ElastPQ as part of routine clinical care. RESULTS: We enrolled 671 patients with NAFLD, mean age 55.8 ± 13 years, body mass index (BMI) 31.5 ± 5.7 kg/m2 , 56.6% males, 41% diabetes, 53.7% hypertension, 68% dyslipidaemia. ElastPQ showed an excellent correlation with F-TE (Spearman's r = 0.80, p < .001), which was better for mild/moderate stages of fibrosis. Independent predictors of a >2 kPa discrepancy between the two techniques were a larger waist circumference and F-TE ≥10 kPa. In the subgroup of 159 patients with available histology, ElastPQ showed similar diagnostic accuracy with F-TE in staging liver fibrosis (ElastPQ area under the curves 0.84, 0.83, 0.86 and 0.95, for F ≥ 1, F ≥ 2, F ≥ 3 and F = 4 respectively). Optimal cut-off values of ElastPQ for individual fibrosis stages were lower than those of F-TE. CONCLUSIONS: ElastPQ shows an excellent correlation with F-TE in patients with NAFLD, which was better for lower LSM. The optimal cut-off values of ElastPQ are lower than those of F-TE for individual stages of fibrosis. ElastPQ has similar diagnostic accuracy to F-TE for all stages of fibrosis.

Inhibition of TLR7 and TLR9 Reduces Human Cholangiocarcinoma Cell Proliferation and Tumor Development.

BACKGROUND: Toll-like receptors (TLRs) are key players in innate immunity and modulation of TLR signaling has been demonstrated to profoundly affect proliferation and growth in different types of cancer. However, the role of TLRs in human intrahepatic cholangiocarcinoma (ICC) pathogenesis remains largely unexplored. AIMS: We set out to determine if TLRs play any role in ICCs which could potentially make them useful treatment targets. METHODS: Tissue microarrays containing samples from 9 human ICCs and normal livers were examined immunohistochemically for TLR4, TLR7, and TLR9 expression. Proliferation of human ICC cell line HuCCT1 was measured by MTS assay following treatment with CpG-ODN (TLR9 agonist), imiquimod (TLR7 agonist), chloroquine (TLR7 and TLR9 inhibitor) and IRS-954 (TLR7 and TLR9 antagonist). The in vivo effects of CQ and IRS-954 on tumor development were also examined in a NOD-SCID mouse xenograft model of human ICC. RESULTS: TLR4 was expressed in all normal human bile duct epithelium but absent in the majority (60%) of ICCs. TLR7 and TLR9 were expressed in 80% of human ICCs. However, TLR7 was absent in all cases of normal human bile duct epithelium and only one was TLR9 positive. HuCCT1 cell proliferation in vitro significantly increased following IMQ or CpG-ODN treatment (P < 0.03 and P < 0.002, respectively) but decreased with CQ (P < 0.02). In the mouse xenograft model there was significant reduction in size of tumors from CQ and IRS-954 treated mice compared to untreated controls. CONCLUSION: TLR7 and TLR9 should be further explored for their potential as actionable targets in the treatment of ICC.

Biopsy for advanced hepatocellular carcinoma: results of a multicentre UK audit.

BACKGROUND: Advanced hepatocellular carcinoma (HCC) is commonly diagnosed using non-invasive radiological criteria (NIRC) defined by the European Association for the Study of the Liver or the American Association for the Study of Liver Diseases. In 2017, The National Institute for Clinical Excellence mandated histological confirmation of disease to authorise the use of sorafenib in the UK. METHODS: This was a prospective multicentre audit in which patients suitable for sorafenib were identified at multidisciplinary meetings. The primary analysis cohort (PAC) was defined by the presence of Child-Pugh class A liver disease and performance status 0-2. Clinical, radiological and histological data were reported locally and collected on a standardised case report form. RESULTS: Eleven centres reported 418 cases, of which 361 comprised the PAC. Overall, 76% had chronic liver disease and 66% were cirrhotic. The diagnostic imaging was computed tomography in 71%, magnetic resonance imaging in 27% and 2% had both. Pre-existing histology was available in 45 patients and 270 underwent a new biopsy, which confirmed HCC in 93.4%. Alternative histological diagnoses included cholangiocarcinoma (CC) and combined HCC-CC. In cirrhotic patients, NIRC criteria had a sensitivity of 65.4% and a positive predictive value of 91.4% to detect HCC. Two patients (0.7%) experienced mild post-biopsy bleeding. CONCLUSION: The diagnostic biopsy is safe and feasible for most patients eligible for systemic therapy.

AICAR and compound C negatively modulate HCC-induced primary human hepatic stellate cell activation in vitro.

Tumor stroma and microenvironment have been shown to affect hepatocellular carcinoma (HCC) growth, with activated hepatic stellate cells (HSC) as a major contributor in this process. Recent evidence suggests that the energy sensor adenosine monophosphate-activated kinase (AMPK) may mediate a series of essential processes during carcinogenesis and HCC progression. Here, we investigated the effect of different HCC cell lines with known TP53 or CTNBB1 mutations on primary human HSC activation, proliferation, and AMPK activation. We show that conditioned media obtained from multiple HCC cell lines differently modulate human hepatic stellate cell (hHSC) proliferation and hHSC AMPK activity in a paracrine manner. Pharmacological treatment of hHSC with AICAR and Compound C inhibited the HCC-induced proliferation/activation of hHSC through AMPK-dependent and AMPK-independent mechanisms, which was further confirmed using mouse embryonic fibroblasts (MEFs) deficient of both catalytic AMPKα isoforms (AMPKα1/α2-/-) and wild type (wt) MEF. Both compounds induced S-phase cell-cycle arrest and, in addition, AICAR inhibited the mTORC1 pathway by inhibiting phosphorylation of 4E-BP1 and S6 in hHSC and wt MEF. Data mining of the Cancer Genome Atlas (TCGA) and the Liver Cancer (LICA-FR) showed that AMPKα1 (PRKAA1) and AMPKα2 (PRKAA2) expression differed depending on the mutation (TP53 or CTNNB1), tumor grading, and G1-G6 classification, reflecting the heterogeneity in human HCC. Overall, we provide evidence that AMPK modulating pharmacological agents negatively modulate HCC-induced hHSC activation and may therefore provide a novel approach to target the mutual, tumor-promoting interactions between hHSC and HCC.NEW & NOTEWORTHY HCC is marked by genetic heterogeneity and activated hepatic stellate cells (HSC) are considered key players during HCC development. The paracrine effect of different HCC cell lines on the activation of primary hHSC was accompanied by differential AMPK activation depending on the HCC line used. Pharmacological treatment inhibited the HCC-induced hHSC activation through AMPK-dependent and AMPK-independent mechanisms. This heterogenic effect on HCC-induced AMPK activation was confirmed by data mining TCGA and LICA-FR databases.

Collagen proportionate area correlates with histological stage and predicts clinical events in primary sclerosing cholangitis.

BACKGROUND & AIMS: Primary sclerosing cholangitis (PSC) is a chronic cholestatic liver disease in need of accurate biomarkers for stratification and as surrogates for clinical endpoints in trials. Quantitative liver fibrosis assessment by collagen proportionate area (CPA) measurement has been demonstrated to correlate with clinical outcomes in chronic hepatitis C, alcohol-related and non-alcoholic fatty liver disease. We aimed to investigate the ability of CPA to quantify liver fibrosis and predict clinical events in PSC. METHODS: Biopsies from 101 PSC patients from two European centres were retrospectively assessed by two expert pathologists in tandem, using grading (Ishak and Nakanuma) and staging (Ishak, Nakanuma, Ludwig) systems recently validated to predict clinical events in PSC. CPA was determined by image analysis of picro-Sirius red-stained sections following a standard protocol. We assessed the correlations between CPA, staging and grading and their associations with three outcomes: (1) time to PSC-related death, liver transplant or primary liver cancer; (2) liver transplant-free survival; (3) occurrence of cirrhosis-related clinical manifestations. RESULTS: CPA correlated strongly with histological stage determined by each scoring system (P < .001) and was significantly associated with the three endpoints. Median time to endpoint-1, endpoint-2 and endpoint-3 was shorter in patients with higher CPA, on Kaplan-Meier analyses (P = .011, P = .034 and P = .001, respectively). CONCLUSION: Quantitative fibrosis assessment by CPA has utility in PSC. It correlates with established histological staging systems and predicts clinical events. CPA may be a useful tool for staging fibrosis and for risk stratification in PSC and should be evaluated further within prospective clinical trials.

Understanding the Treatment Algorithm of Patients with Metastatic Pancreatic Neuroendocrine Neoplasms: A Single-Institution Retrospective Analysis Comparing Outcomes of Chemotherapy, Molecular Targeted Therapy, and Peptide Receptor Radionuclide Therapy in 255 Patients.

BACKGROUND: The number of therapeutic options for patients with pancreatic neuroendocrine neoplasms (PNEN) has increased, but the optimal therapeutic algorithm has not been defined due to lack of randomised trials comparing different modalities. METHODS: We performed a retrospective study in patients with metastatic PNEN treated with ≥1 line of systemic therapy. The relationship between baseline characteristics, treatment type, and time to treatment failure (TTF), time to progression (TTP), and overall survival (OS) was analysed using the Kaplan-Meier method. Univariate and multivariate analyses were performed using the Cox proportional hazards model. RESULTS: Two hundred and fifty-five patients with metastatic PNEN had 491 evaluable lines of therapy. Independent predictors of TTF included treatment type, Ki-67, tumour grade, and chromogranin A. To reduce selection bias, a subgroup of 114 patients with grade 2 (G2) metastatic pancreatic neuroendocrine tumours (PNET) was analysed separately. These patients had received 234 lines of treatment (105 chemotherapy, 82 molecular targeted therapy, and 47 peptide receptor radionuclide therapy [PRRT]). In the G2 cohort, TTF and TTP were superior for PRRT compared with both chemotherapy and molecular targeted therapy. OS in the G2 cohort was also superior for those that had received PRRT compared with those that had not (median 84 vs. 56 months; HR 0.55, 95% CI: 0.31-0.98, p = 0.04). CONCLUSIONS: This study suggests that PRRT is associated with superior clinical outcomes relative to other systemic therapies for G2 metastatic PNET. Prospective studies are required to confirm these observations.

Diagnostic Approaches to Neuroendocrine Neoplasms of Unknown Primary Site.

Neuroendocrine neoplasms (NENs) arise from cells of neuronal and endocrine differentiation. While they are a rare entity, an increasing proportion of patients with NEN present with metastatic disease and no evident primary site using routine imaging or histopathology. NENs of unknown primary site have a poorer prognosis, often due to the challenge of selecting appropriate evidence-based management. We review the available literature and guidelines for the management of NENs of unknown primary site including clinical features, biochemical tests, histopathology, imaging, surgical exploration and localised and systemic treatments. We also discuss novel molecular techniques currently under investigation to aid primary site identification.

The adenosine monophosphate-activated protein kinase-vacuolar adenosine triphosphatase-pH axis: A key regulator of the profibrogenic phenotype of human hepatic stellate cells.

Liver fibrosis and cirrhosis are characterized by activation of hepatic stellate cells (HSCs), which is associated with higher intracellular pH (pHi). The vacuolar H+ adenosine-triphosphatase (v-ATPase) multisubunit complex is a key regulator of pHi homeostasis. The present work investigated the functional role of v-ATPase in primary human HSC (hHSC) activation and its modulation by specific adenosine monophosphate-activated protein kinase (AMPK) subunits. We demonstrate that the expression of different v-ATPase subunits was increased in in vivo and in vitro activated hHSCs compared to nonactivated hHSCs. Specific inhibition of v-ATPase with bafilomycin and KM91104 induced a down-regulation of the HSC fibrogenic gene profile, which coincided with increased lysosomal pH, decreased pHi, activation of AMPK, reduced proliferation, and lower metabolic activity. Similarly, pharmacological activation of AMPK by treatment with diflunisal, A769662, and ZLN024 reduced the expression of v-ATPase subunits and profibrogenic markers. v-ATPase expression was differently regulated by the AMPK α1 subunit (AMPKα1) and AMPKα2, as demonstrated in mouse embryo fibroblasts specifically deficient for AMPK α subunits. In addition, activation of v-ATPase in hHSCs was shown to be AMPKα1-dependent. Accordingly, pharmacological activation of AMPK in AMPKα1-depleted hHSCs prevented v-ATPase down-regulation. Finally, we showed that v-ATPase expression was increased in fibrotic livers from bile duct-ligated mice and in human cirrhotic livers. CONCLUSION: The down-regulation of v-ATPase might represent a promising target for the development of antifibrotic strategies. (Hepatology 2018).

Evaluating the association of serum ferritin and hepatic iron with disease severity in non-alcoholic fatty liver disease.

BACKGROUND & AIMS: Hyperferritinemia, with or without increased hepatic iron, represents a common finding in non-alcoholic fatty liver disease (NAFLD). However, it is unclear whether it reflects hepatic inflammation or true iron-overload and, in case the latter is confirmed, whether this influences disease progression. We therefore explored the association between serum ferritin, degree and pattern of hepatic iron deposition and liver disease severity in patients with NAFLD. METHODS: We selected 468 patients with biopsy-proven NAFLD from 2 European centres. Iron, hepatic and metabolic parameters were collected at the time of liver biopsy. Iron deposits in hepatocytes and reticuloendothelial cells were assessed and graded. Diagnosis of non-alcoholic steatohepatitis (NASH) and fibrosis staging were performed. RESULTS: A total of 122 (26%) patients had hyperferritinemia, whereas stainable hepatic iron was found in 116 (25%) patients (38% predominantly in hepatocytes, 20% in reticuloendothelial cells and 42% in both). Subjects with stainable hepatic iron, particularly those with a mixed pattern, had higher serum ferritin and transaminases but only a mixed pattern of iron deposition was among the variables significantly associated with presence of NASH. Serum ferritin was not associated with presence of NASH, however it increased with worsening fibrosis stage (F3 compared to F0-F1), and significantly decreased in stage F4. CONCLUSIONS: A mixed pattern of hepatic iron deposition is associated with the presence of steatohepatitis, while serum ferritin increases with worsening fibrosis up to pre-cirrhotic stage. In individual NAFLD patients, serum ferritin could be evaluated as part of non-invasive diagnostic panels but not on its own.

Challenging the Current Risk Factors of Appendiceal Neuroendocrine Neoplasms: Can They Accurately Predict Local Lymph Nodal Invasion? Results from a Large Case Series.

BACKGROUND: Appendiceal neuroendocrine neoplasms (ANEN) are uncommon entities, which run mostly an indolent course. Appendicectomy alone is usually curative, except for in a selected group of patients that are deemed to be at risk of loco-regional metastases, in whom a completion right hemicolectomy (RHC) is recommended. The current "Guidelines" criteria for the latter have been controversial, and may result in overtreatment, which is concerning for a young patient population. OBJECTIVE: The aim of this study is to evaluate the prognostic value of the current criteria in identifying more accurately those at-risk patients. METHODS: This was a retrospective study of the 263 cases of ANEN referred for advice or management to a tertiary referral unit over a 10-year period. Seventy-two patients underwent RHC, based on criteria, suggested by International Guidelines. Each one of those was assessed to identify whether it correlated with lymph node invasion (LNI) at the RHC surgical specimen. RESULTS: Tumour grade (p < 0.001), vascular (p = 0.044) and lymph vessel invasion (p < 0.001) were all found to be statistically significant independent risk factors for LNI identified following RHC, whilst tumour size (p = 0.375) and mesoappendiceal invasion (MAI) (p = 0.317) were not statistically significant. However, deep MAI and tumour size >2 cm showed a correlation with each other on LNI positive subgroup analysis. Location in appendiceal base made LNI more likely but again was not significant (p = 0.133). CONCLUSIONS: Higher tumour grade and lymphovascular invasion should be considered as the most important risk prognosticators. Surprisingly, tumour size was not found to be significant in our cohort. Further international multicentre studies with large numbers of patients are needed to fully validate those data.

CHK2 overexpression and mislocalisation within mitotic structures enhances chromosomal instability and hepatocellular carcinoma progression.

OBJECTIVE: Chromosomal instability (CIN) is the most common form of genomic instability, which promotes hepatocellular carcinoma (HCC) progression by enhancing tumour heterogeneity, drug resistance and immunity escape. CIN per se is an important factor of DNA damage, sustaining structural chromosome abnormalities but the underlying mechanisms are unknown. DESIGN: DNA damage response protein checkpoint kinase 2 (Chk2) expression was evaluated in an animal model of diethylnitrosamine-induced HCC characterised by DNA damage and elevated mitotic errors. Chk2 was also determined in two discrete cohorts of human HCC specimens. To assess the functional role of Chk2, gain on and loss-of-function, mutagenesis, karyotyping and immunofluorescence/live imaging were performed by using HCT116, Huh7 and human hepatocytes immortalised with hTERT gene (HuS). RESULTS: We demonstrate that mitotic errors during HCC tumorigenesis cause lagging chromosomes/DNA damage and activation of Chk2. Overexpression/phosphorylation and mislocalisation within the mitotic spindle of Chk2 contributes to induce lagging chromosomes. Lagging chromosomes and mitotic activity are reversed by knockdown of Chk2. Furthermore, upregulated Chk2 maintains mitotic activity interacting with Aurora B kinase for chromosome condensation and cytokinesis. The forkhead-associated domain of Chk2 is required for Chk2 mislocalisation to mitotic structures. In addition, retinoblastoma protein phosphorylation contributes to defective mitoses. A cohort and independent validation cohort show a strong cytoplasm to nuclear Chk2 translocation in a subset of patients with HCC. CONCLUSIONS: The study reveals a new mechanistic insight in the coinvolvement of Chk2 in HCC progression. These findings propose Chk2 as a putative biomarker to detect CIN in HCC providing a valuable support for clinical/therapeutical management of patients.

CD36 palmitoylation disrupts free fatty acid metabolism and promotes tissue inflammation in non-alcoholic steatohepatitis.

BACKGROUND AND AIMS: Fatty acid translocase CD36 (CD36) is a membrane protein with multiple immuno-metabolic functions. Palmitoylation has been suggested to regulate the distribution and functions of CD36, but little is known about its significance in non-alcoholic steatohepatitis (NASH). METHODS: Human liver tissue samples were obtained from patients undergoing liver biopsy for diagnostic purposes. CD36 knockout mice were injected with lentiviral vectors expressing wild-type CD36 or CD36 with mutated palmitoylation sites. Liver histology, immunofluorescence, mRNA expression profile, subcellular distributions and functions of CD36 protein were assessed. RESULTS: The localization of CD36 on the plasma membrane of hepatocytes was markedly increased in patients with NASH compared to patients with normal liver and those with simple steatosis. Increased CD36 palmitoylation and increased localization of CD36 on the plasma membrane of hepatocytes were also observed in livers of mice with NASH. Furthermore, inhibition of CD36 palmitoylation protected mice from developing NASH. The absence of palmitoylation decreased CD36 protein hydrophobicity reducing its localization on the plasma membrane as well as in lipid raft of hepatocytes. Consequently, a lack of palmitoylation decreased fatty acid uptake and CD36/Fyn/Lyn complex in HepG2 cells. Inhibition of CD36 palmitoylation not only ameliorated intracellular lipid accumulation via activation of the AMPK pathway, but also inhibited the inflammatory response through the inhibition of the JNK signaling pathway. CONCLUSIONS: Our findings demonstrate the key role of palmitoylation in regulating CD36 distributions and its functions in NASH. Inhibition of CD36 palmitoylation may represent an effective therapeutic strategy in patients with NASH. LAY SUMMARY: Fatty acid translocase CD36 (CD36) is a multifunctional membrane protein which contributes to the development of liver steatosis. In the present study, we demonstrated that the localization of CD36 on the plasma membrane of hepatocytes is increased in patients with non-alcoholic steatohepatitis. Blocking the palmitoylation of CD36 reduces CD36 distribution in hepatocyte plasma membranes and protects mice from non-alcoholic steatohepatitis. The inhibition of CD36 palmitoylation not only improved fatty acid metabolic disorders but also reduced the inflammatory response in vitro and in vivo. The present study suggests that CD36 palmitoylation is important for non-alcoholic steatohepatitis development and inhibition of CD36 palmitoylation could be used to cure non-alcoholic steatohepatitis.

Pathogenesis of biliary fibrosis.

Chronic cholestatic liver diseases such as primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC) are associated with active hepatic fibrogenesis, and, ultimately, to the development of cirrhosis. However, the precise relationship between cholestasis, in its broad meaning, and liver tissue fibrosis is still poorly defined. Fibrogenesis is currently viewed as a dynamic process that appears strictly related to the extent and duration of parenchymal injury. This relationship is clearly evident in the presence of reiterative hepatocellular necrosis due to viral infection or alcohol abuse. It appears that "pure" intralobular intrahepatic cholestasis secondary to biliary secretory failure of the hepatocyte, in absence of hepatocellular damage, lobular inflammation and bile duct damage and/or proliferation, is not associated with marked and/or progressive liver tissue fibrosis. In contrast, marked and progressive liver tissue fibrosis always follows liver diseases characterized by chronic inflammatory bile duct damage as seen in PBC and PSC or chronic mechanical obstruction of the biliary tree. Overall, the fibrogenic process in these clinical conditions appears to be related to a more complex interaction between immune/inflammatory mechanisms, cytokine networks and the derangement of the homeostasis between epithelial and mesenchymal cells. The elucidation of these mechanisms is indeed crucial for the identification of potential diagnostic and therapeutic targets.

Evaluation of Clinical Prognostic Factors and Further Delineation of the Effect of Mesenteric Fibrosis on Survival in Advanced Midgut Neuroendocrine Tumours.

BACKGROUND: Small intestinal neuroendocrine tumours (SI NETs) represent 30-50% of small bowel neoplasms and often present at an advanced stage. To date, there is relatively limited literature regarding prognostic factors affecting overall survival (OS) in stage IV disease. In addition, the prevalence of mesenteric fibrosis (MF) in SI NETs and its effect on OS have not been sufficiently explored in the literature. AIM: The primary aim of this study was to perform a large-scale survival analysis in an institutional cohort of 387 patients with metastatic (stage IV) SI NETs. The secondary aim was to provide epidemiological information regarding the prevalence of MF and to evaluate its effect on OS. RESULTS: The median OS was 101 months (95% CI 84, 118). Age > 65 years, mesenteric metastases with and without desmoplasia, liver metastases, carcinoid heart disease (CHD) and bone metastases were associated with a significantly shorter OS, while primary tumour resection was predictive of a longer OS. The benefit of surgical resection was limited to symptomatic patients. MF was present in approximately 50% of patients with mesenteric lymphadenopathy. Elevated urinary 5-HIAA levels correlated strongly with the presence of CHD (p < 0.001) and to a lesser extent (p = 0.02) with MF. MF and CHD did not usually co-exist, suggesting that different mechanisms are likely to be involved in the development of these fibrotic complications. CONCLUSIONS: This study has identified specific prognostic factors in a large cohort of 387 patients with advanced SI NETs and has provided useful epidemiological data regarding carcinoid-related fibrotic complications.

A novel SOD1-ALS mutation separates central and peripheral effects of mutant SOD1 toxicity.

Transgenic mouse models expressing mutant superoxide dismutase 1 (SOD1) have been critical in furthering our understanding of amyotrophic lateral sclerosis (ALS). However, such models generally overexpress the mutant protein, which may give rise to phenotypes not directly relevant to the disorder. Here, we have analysed a novel mouse model that has a point mutation in the endogenous mouse Sod1 gene; this mutation is identical to a pathological change in human familial ALS (fALS) which results in a D83G change in SOD1 protein. Homozgous Sod1(D83G/D83G) mice develop progressive degeneration of lower (LMN) and upper motor neurons, likely due to the same unknown toxic gain of function as occurs in human fALS cases, but intriguingly LMN cell death appears to stop in early adulthood and the mice do not become paralyzed. The D83 residue coordinates zinc binding, and the D83G mutation results in loss of dismutase activity and SOD1 protein instability. As a result, Sod1(D83G/D83G) mice also phenocopy the distal axonopathy and hepatocellular carcinoma found in Sod1 null mice (Sod1(-/-)). These unique mice allow us to further our understanding of ALS by separating the central motor neuron body degeneration and the peripheral effects from a fALS mutation expressed at endogenous levels.

Expression of somatostatin receptors 2 and 5 in circulating tumour cells from patients with neuroendocrine tumours.

BACKGROUND: Neuroendocrine tumours (NET) overexpress somatostatin receptors (SSTR) that can be targeted for therapy. Somatostatin receptor expression is routinely measured by molecular imaging but the resolution is insufficient to define heterogeneity. We hypothesised that SSTR expression could be measured on circulating tumour cells (CTCs) and used to investigate heterogeneity of expression and track changes during therapy. METHODS: MCF-7 cells were transfected with SSTR2 or 5 and spiked into donor blood for analysis by CellSearch. Optimum anti-SSTR antibody concentration and exposure time were determined, and flow cytometry was used to evaluate assay sensitivity. For clinical evaluation, blood was analysed by CellSearch, and SSTR2/5 immunohistochemistry was performed on matched tissue samples. RESULTS: Flow cytometry confirmed CellSearch was sensitive and that detection of SSTR was unaffected by the presence of somatostatin analogue up to a concentration of 100 ng ml-l. Thirty-one NET patients were recruited: grade; G1 (29%), G2 (45%), G3 (13%), primary site; midgut (58%), pancreatic (39%). Overall, 87% had SSTR-positive tumours according to somatostatin receptor scintigraphy or 68-Ga-DOTATE PET/CT. Circulating tumour cells were detected in 21 out of 31 patients (68%), of which 33% had evidence of heterogeneous expression of either SSTR2 (n=5) or SSTR5 (n=2). CONCLUSIONS: Somatostatin receptors 2 and 5 are detectable on CTCs from NET patients and may be a useful biomarker for evaluating SSTR-targeted therapies and this is being prospectively evaluated in the Phase IV CALMNET trial (NCT02075606).

Effect of toll-like receptor 7 and 9 targeted therapy to prevent the development of hepatocellular carcinoma.

BACKGROUND & AIMS: Chronic liver disease is a predisposing factor for development of hepatocellular carcinoma (HCC). Toll-like receptors play a crucial role in immunity against microbial pathogens and recent evidence suggests that they may also be important in pathogenesis of chronic liver disease. The purpose of this study was to determine whether TLR7 and TLR9 are potential targets for prevention and progression of HCC. METHODS: Tissue microarrays containing liver samples from patients with cirrhosis, viral hepatitis and HCC were examined for expression of TLR7 and TLR9 and the data obtained was validated in liver specimens from the hospital archives. Proliferation of human HCC cell lines was studied following stimulation of TLR7 and TLR9 using agonists (imiquimod and CpG-ODN respectively) and inhibition with a specific antagonist (IRS-954) or chloroquine. The effect of these interventions was confirmed in a xenograft model and diethylnitrosamine (DEN)/nitrosomorpholine (NMOR)-induced model of HCC. RESULTS: TLR7 and TLR9 expression was up-regulated in human HCC tissue. Proliferation of HuH7 cells in vitro increased significantly in response to stimulation of TLR7. TLR7 and TLR9 inhibition using IRS-954 or chloroquine significantly reduced HuH7 cell proliferation in vitro and inhibited tumour growth in the mouse xenograft model. HCC development in the DEN/NMOR rat model was also significantly inhibited by chloroquine (P < 0.001). CONCLUSION: The data suggest that inhibiting TLR7 and TLR9 with IRS-954 or chloroquine could potentially be used as a novel therapeutic approach for preventing HCC development and/or progression in susceptible patients.