SRF617 Is a Potent Inhibitor of CD39 with Immunomodulatory and Antitumor Properties.

CD39 (ENTPD1) is a key enzyme responsible for degradation of extracellular ATP and is upregulated in the tumor microenvironment (TME). Extracellular ATP accumulates in the TME from tissue damage and immunogenic cell death, potentially initiating proinflammatory responses that are reduced by the enzymatic activity of CD39. Degradation of ATP by CD39 and other ectonucleotidases (e.g., CD73) results in extracellular adenosine accumulation, constituting an important mechanism for tumor immune escape, angiogenesis induction, and metastasis. Thus, inhibiting CD39 enzymatic activity can inhibit tumor growth by converting a suppressive TME to a proinflammatory environment. SRF617 is an investigational, anti-CD39, fully human IgG4 Ab that binds to human CD39 with nanomolar affinity and potently inhibits its ATPase activity. In vitro functional assays using primary human immune cells demonstrate that inhibiting CD39 enhances T-cell proliferation, dendritic cell maturation/activation, and release of IL-1ß and IL-18 from macrophages. In vivo, SRF617 has significant single-agent antitumor activity in human cell line-derived xenograft models that express CD39. Pharmacodynamic studies demonstrate that target engagement of CD39 by SRF617 in the TME inhibits ATPase activity, inducing proinflammatory mechanistic changes in tumor-infiltrating leukocytes. Syngeneic tumor studies using human CD39 knock-in mice show that SRF617 can modulate CD39 levels on immune cells in vivo and can penetrate the TME of an orthotopic tumor, leading to increased CD8+ T-cell infiltration. Targeting CD39 is an attractive approach for treating cancer, and, as such, the properties of SRF617 make it an excellent drug development candidate.

CD73 Inhibits cGAS-STING and Cooperates with CD39 to Promote Pancreatic Cancer.

The ectonucleotidases CD39 and CD73 catalyze extracellular ATP to immunosuppressive adenosine, and as such, represent potential cancer targets. We investigated biological impacts of CD39 and CD73 in pancreatic ductal adenocarcinoma (PDAC) by studying clinical samples and experimental mouse tumors. Stromal CD39 and tumoral CD73 expression significantly associated with worse survival in human PDAC samples and abolished the favorable prognostic impact associated with the presence of tumor-infiltrating CD8+ T cells. In mouse transplanted KPC tumors, both CD39 and CD73 on myeloid cells, as well as CD73 on tumor cells, promoted polarization of infiltrating myeloid cells towards an M2-like phenotype, which enhanced tumor growth. CD39 on tumor-specific CD8+ T cells and pancreatic stellate cells also suppressed IFNγ production by T cells. Although therapeutic inhibition of CD39 or CD73 alone significantly delayed tumor growth in vivo, targeting of both ectonucleotidases exhibited markedly superior antitumor activity. CD73 expression on human and mouse PDAC tumor cells also protected against DNA damage induced by gemcitabine and irradiation. Accordingly, large-scale pharmacogenomic analyses of human PDAC cell lines revealed significant associations between CD73 expression and gemcitabine chemoresistance. Strikingly, increased DNA damage in CD73-deficient tumor cells associated with activation of the cGAS-STING pathway. Moreover, cGAS expression in mouse KPC tumor cells was required for antitumor activity of the CD73 inhibitor AB680 in vivo. Our study, thus, illuminates molecular mechanisms whereby CD73 and CD39 seemingly cooperate to promote PDAC progression.

Cytomegalovirus Hepatitis in Allograft Livers May Show Histologic Features of Acute Cellular Rejection.

CONTEXT.­: Cytomegalovirus (CMV) hepatitis in allograft livers is an important infectious complication, with histology that historically has been described to overlap with that of acute cellular rejection (ACR), a diagnosis that compels a different treatment regimen. OBJECTIVE.­: To update the clinicopathologic features of CMV hepatitis and explore its clinical and histologic relationship with ACR. DESIGN.­: A retrospective analysis of 26 patients with a diagnosis of CMV hepatitis across 4 institutions was performed, including clinical, histologic, and immunohistochemical features. RESULTS.­: Patients were predominantly CMV donor positive/recipient negative (D+/R-; n = 9 of 15) and received a diagnosis of CMV hepatitis at a mean age of 52 years (SD, 17 years), at a mean interval of 184 days (SD, 165 days) from transplantation. Mean CMV viral load at diagnosis was 241 000 IU/mL (SD, 516 000 IU/mL), and liver biochemical enzymes were elevated (mean alanine aminotransferase, 212 U/L [SD, 180 U/L]; mean aspartate aminotransferase, 188 U/L [SD, 151 U/L]; mean alkaline phosphatase, 222 U/L [SD, 153 U/L]). Ten cases did not show histologic features of ACR, and 16 cases demonstrated features of ACR (including marked bile duct injury and endotheliitis). Viral cytopathic change was found in all cases. All patients were treated with a combination of antiviral therapy and CMV intravenous immunoglobulin, with near resolution of biochemical enzymes in all patients with undetectable serum CMV viral titers. CONCLUSIONS.­: CMV hepatitis and ACR are complex processes with interlinking mechanisms that are important to distinguish. A subset of transplantation patients with CMV hepatitis show histologic changes that mimic ACR but were treated successfully with antiviral therapy alone.

Expression of IGF-1 receptor and GH receptor in hepatic tissue of patients with nonalcoholic fatty liver disease and nonalcoholic steatohepatitis.

OBJECTIVE: The GH and IGF-1 axis is a candidate disease-modifying target in nonalcoholic fatty liver disease (NAFLD) given its lipolytic, anti-inflammatory and anti-fibrotic properties. IGF-1 receptor (IGF-1R) and GH receptor (GHR) expression in adult, human hepatic tissue is not well understood across the spectrum of NAFLD severity. Therefore, we sought to investigate hepatic IGF-1R and GHR expression in subjects with NAFLD utilizing gene expression analysis (GEA) and immunohistochemistry (IHC). DESIGN: GEA (n = 318) and IHC (n = 30) cohorts were identified from the Massachusetts General Hospital NAFLD Tissue Repository. GEA subjects were categorized based on histopathology as normal liver histology (NLH), steatosis only (Steatosis), nonalcoholic steatohepatitis (NASH) without fibrosis (NASH F0), and NASH with fibrosis (NASH F1-4) with GEA by the Nanostring nCounter assay. IHC subjects were matched for age, body mass index (BMI), sex, and diabetic status across three groups (n = 10 each): NLH, Steatosis, and NASH with fibrosis (NASH F1-3). IHC for IGF-1R, IGF-1 and GHR was performed on formalin-fixed, paraffin-embedded hepatic tissue samples. RESULTS: IGF-1R gene expression did not differ across NAFLD severity while IGF-1 gene expression decreased with increasing NAFLD severity, including when controlled for BMI and age. GHR expression did not differ by severity of NAFLD based on GEA or IHC. CONCLUSIONS: IGF-1R and GHR expression levels were not significantly different across NAFLD disease severity. However, expression of IGF-1 was lower with increasing severity of NAFLD. Additional research is needed regarding the contribution of the GH/IGF-1 axis to the pathophysiology of NAFLD and NASH.

IL27 Signaling Serves as an Immunologic Checkpoint for Innate Cytotoxic Cells to Promote Hepatocellular Carcinoma.

Although inflammatory mechanisms driving hepatocellular carcinoma (HCC) have been proposed, the regulators of anticancer immunity in HCC remain poorly understood. We found that IL27 receptor (IL27R) signaling promotes HCC development in vivo. High IL27EBI3 cytokine or IL27RA expression correlated with poor prognosis for patients with HCC. Loss of IL27R suppressed HCC in vivo in two different models of hepatocarcinogenesis. Mechanistically, IL27R sig-naling within the tumor microenvironment restrains the cytotoxicity of innate cytotoxic lymphocytes. IL27R ablation enhanced their accumulation and activation, whereas depletion or functional impairment of innate cytotoxic cells abrogated the effect of IL27R disruption. Pharmacologic neutralization of IL27 signaling increased infiltration of innate cytotoxic lymphocytes with upregulated cytotoxic molecules and reduced HCC development. Our data reveal an unexpected role of IL27R signaling as an immunologic checkpoint regulating innate cytotoxic lymphocytes and promoting HCC of different etiologies, thus indicating a therapeutic potential for IL27 pathway blockade in HCC. SIGNIFICANCE: HCC, the most common form of liver cancer, is characterized by a poor survival rate and limited treatment options. The discovery of a novel IL27-dependent mechanism controlling anticancer cytotoxic immune response will pave the road for new treatment options for this devastating disease. This article is highlighted in the In This Issue feature, p. 1825.

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.

Distinct Hepatic Gene-Expression Patterns of NAFLD in Patients With Obesity.

Approaches to manage nonalcoholic fatty liver disease (NAFLD) are limited by an incomplete understanding of disease pathogenesis. The aim of this study was to identify hepatic gene-expression patterns associated with different patterns of liver injury in a high-risk cohort of adults with obesity. Using the NanoString Technologies (Seattle, WA) nCounter assay, we quantified expression of 795 genes, hypothesized to be involved in hepatic fibrosis, inflammation, and steatosis, in liver tissue from 318 adults with obesity. Liver specimens were categorized into four distinct NAFLD phenotypes: normal liver histology (NLH), steatosis only (steatosis), nonalcoholic steatohepatitis without fibrosis (NASH F0), and NASH with fibrosis stage 1-4 (NASH F1-F4). One hundred twenty-five genes were significantly increasing or decreasing as NAFLD pathology progressed. Compared with NLH, NASH F0 was characterized by increased inflammatory gene expression, such as gamma-interferon-inducible lysosomal thiol reductase (IFI30) and chemokine (C-X-C motif) ligand 9 (CXCL9), while complement and coagulation related genes, such as C9 and complement component 4 binding protein beta (C4BPB), were reduced. In the presence of NASH F1-F4, extracellular matrix degrading proteinases and profibrotic/scar deposition genes, such as collagens and transforming growth factor beta 1 (TGFB1), were simultaneously increased, suggesting a dynamic state of tissue remodeling. Conclusion: In adults with obesity, distinct states of NAFLD are associated with intrahepatic perturbations in genes related to inflammation, complement and coagulation pathways, and tissue remodeling. These data provide insights into the dynamic pathogenesis of NAFLD in high-risk individuals.

A human liver cell-based system modeling a clinical prognostic liver signature for therapeutic discovery.

Chronic liver disease and hepatocellular carcinoma (HCC) are life-threatening diseases with limited treatment options. The lack of clinically relevant/tractable experimental models hampers therapeutic discovery. Here, we develop a simple and robust human liver cell-based system modeling a clinical prognostic liver signature (PLS) predicting long-term liver disease progression toward HCC. Using the PLS as a readout, followed by validation in nonalcoholic steatohepatitis/fibrosis/HCC animal models and patient-derived liver spheroids, we identify nizatidine, a histamine receptor H2 (HRH2) blocker, for treatment of advanced liver disease and HCC chemoprevention. Moreover, perturbation studies combined with single cell RNA-Seq analyses of patient liver tissues uncover hepatocytes and HRH2+, CLEC5Ahigh, MARCOlow liver macrophages as potential nizatidine targets. The PLS model combined with single cell RNA-Seq of patient tissues enables discovery of urgently needed targets and therapeutics for treatment of advanced liver disease and cancer prevention.

Successful use of azithromycin for Escherichia coli-associated renal allograft malakoplakia: a report of two cases.

Malakoplakia is a chronic granulomatous disease associated with incomplete clearance of bacterial pathogens. A multimodal approach to therapy includes antimicrobials with intracellular activity, reduction in immunosuppression, and debulking of lesions. Azithromycin has an intracellular mechanism of action and enhanced Gram-negative activity compared to other macrolides. Despite some in vitro data to support its use, there are no clinical breakpoints or epidemiological cut-off values for most Enterobacterales from the European Committee on Antimicrobial Susceptibility Testing (EUCAST) or the Clinical and Laboratory Standards Institute (CLSI). We present two cases, previously unreported, of Escherichia coli associated renal allograft malakoplakia successfully treated with azithromycin.

Quantitative, noninvasive MRI characterization of disease progression in a mouse model of non-alcoholic steatohepatitis.

Non-alcoholic steatohepatitis (NASH) is an increasing cause of chronic liver disease characterized by steatosis, inflammation, and fibrosis which can lead to cirrhosis, hepatocellular carcinoma, and mortality. Quantitative, noninvasive methods for characterizing the pathophysiology of NASH at both the preclinical and clinical level are sorely needed. We report here a multiparametric magnetic resonance imaging (MRI) protocol with the fibrogenesis probe Gd-Hyd to characterize fibrotic disease activity and steatosis in a common mouse model of NASH. Mice were fed a choline-deficient, L-amino acid-defined, high-fat diet (CDAHFD) to induce NASH with advanced fibrosis. Mice fed normal chow and CDAHFD underwent MRI after 2, 6, 10 and 14 weeks to measure liver T1, T2*, fat fraction, and dynamic T1-weighted Gd-Hyd enhanced imaging of the liver. Steatosis, inflammation, and fibrosis were then quantified by histology. NASH and fibrosis developed quickly in CDAHFD fed mice with strong correlation between morphometric steatosis quantification and liver fat estimated by MRI (r = 0.90). Sirius red histology and collagen quantification confirmed increasing fibrosis over time (r = 0.82). Though baseline T1 and T2* measurements did not correlate with fibrosis, Gd-Hyd signal enhancement provided a measure of the extent of active fibrotic disease progression and correlated strongly with lysyl oxidase expression. Gd-Hyd MRI accurately detects fibrogenesis in a mouse model of NASH with advanced fibrosis and can be combined with other MR measures, like fat imaging, to more accurately assess disease burden.

Targeting clinical epigenetic reprogramming for chemoprevention of metabolic and viral hepatocellular carcinoma.

OBJECTIVE: Hepatocellular carcinoma (HCC) is the fastest-growing cause of cancer-related mortality with chronic viral hepatitis and non-alcoholic steatohepatitis (NASH) as major aetiologies. Treatment options for HCC are unsatisfactory and chemopreventive approaches are absent. Chronic hepatitis C (CHC) results in epigenetic alterations driving HCC risk and persisting following cure. Here, we aimed to investigate epigenetic modifications as targets for liver cancer chemoprevention. DESIGN: Liver tissues from patients with NASH and CHC were analysed by ChIP-Seq (H3K27ac) and RNA-Seq. The liver disease-specific epigenetic and transcriptional reprogramming in patients was modelled in a liver cell culture system. Perturbation studies combined with a targeted small molecule screen followed by in vivo and ex vivo validation were used to identify chromatin modifiers and readers for HCC chemoprevention. RESULTS: In patients, CHC and NASH share similar epigenetic and transcriptomic modifications driving cancer risk. Using a cell-based system modelling epigenetic modifications in patients, we identified chromatin readers as targets to revert liver gene transcription driving clinical HCC risk. Proof-of-concept studies in a NASH-HCC mouse model showed that the pharmacological inhibition of chromatin reader bromodomain 4 inhibited liver disease progression and hepatocarcinogenesis by restoring transcriptional reprogramming of the genes that were epigenetically altered in patients. CONCLUSION: Our results unravel the functional relevance of metabolic and virus-induced epigenetic alterations for pathogenesis of HCC development and identify chromatin readers as targets for chemoprevention in patients with chronic liver diseases.

Hepatic gap junctions amplify alcohol liver injury by propagating cGAS-mediated IRF3 activation.

Alcohol-related liver disease (ALD) accounts for the majority of cirrhosis and liver-related deaths worldwide. Activation of IFN-regulatory factor (IRF3) initiates alcohol-induced hepatocyte apoptosis, which fuels a robust secondary inflammatory response that drives ALD. The dominant molecular mechanism by which alcohol activates IRF3 and the pathways that amplify inflammatory signals in ALD remains unknown. Here we show that cytoplasmic sensor cyclic guanosine monophosphate-adenosine monophosphate (AMP) synthase (cGAS) drives IRF3 activation in both alcohol-injured hepatocytes and the neighboring parenchyma via a gap junction intercellular communication pathway. Hepatic RNA-seq analysis of patients with a wide spectrum of ALD revealed that expression of the cGAS-IRF3 pathway correlated positively with disease severity. Alcohol-fed mice demonstrated increased hepatic expression of the cGAS-IRF3 pathway. Mice genetically deficient in cGAS and IRF3 were protected against ALD. Ablation of cGAS in hepatocytes only phenocopied this hepatoprotection, highlighting the critical role of hepatocytes in fueling the cGAS-IRF3 response to alcohol. We identified connexin 32 (Cx32), the predominant hepatic gap junction, as a critical regulator of spreading cGAS-driven IRF3 activation through the liver parenchyma. Disruption of Cx32 in ALD impaired IRF3-stimulated gene expression, resulting in decreased hepatic injury despite an increase in hepatic steatosis. Taken together, these results identify cGAS and Cx32 as key factors in ALD pathogenesis and as potential therapeutic targets for hepatoprotection.

Hepatic NADH reductive stress underlies common variation in metabolic traits.

The cellular NADH/NAD+ ratio is fundamental to biochemistry, but the extent to which it reflects versus drives metabolic physiology in vivo is poorly understood. Here we report the in vivo application of Lactobacillus brevis (Lb)NOX1, a bacterial water-forming NADH oxidase, to assess the metabolic consequences of directly lowering the hepatic cytosolic NADH/NAD+ ratio in mice. By combining this genetic tool with metabolomics, we identify circulating α-hydroxybutyrate levels as a robust marker of an elevated hepatic cytosolic NADH/NAD+ ratio, also known as reductive stress. In humans, elevations in circulating α-hydroxybutyrate levels have previously been associated with impaired glucose tolerance2, insulin resistance3 and mitochondrial disease4, and are associated with a common genetic variant in GCKR5, which has previously been associated with many seemingly disparate metabolic traits. Using LbNOX, we demonstrate that NADH reductive stress mediates the effects of GCKR variation on many metabolic traits, including circulating triglyceride levels, glucose tolerance and FGF21 levels. Our work identifies an elevated hepatic NADH/NAD+ ratio as a latent metabolic parameter that is shaped by human genetic variation and contributes causally to key metabolic traits and diseases. Moreover, it underscores the utility of genetic tools such as LbNOX to empower studies of 'causal metabolism'.

Advanced fibrosis is associated with incident cardiovascular disease in patients with non-alcoholic fatty liver disease.

BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is associated with an increased risk of cardiovascular disease. It is not well understood, however, which individuals with NAFLD are at highest risk for cardiovascular disease. AIMS: To determine the factors associated with incident cardiovascular events in a prospective cohort of individuals with biopsy-proven NAFLD without pre-existing cardiovascular disease. METHODS: From 2011 to 2018, adults with biopsy-proven NAFLD without cardiovascular disease were enrolled in a tissue repository and were followed prospectively to the first recorded date of incident cardiovascular disease, death or the end of follow-up (11/1/2018). Competing risks analysis was performed to identify predictors of incident cardiovascular disease. RESULTS: After a median follow-up time of 5.2 years, 26/285 (9.1%) individuals experienced an incident cardiovascular event. Advanced fibrosis (stage 3-4) on biopsy was a significant predictor of incident cardiovascular disease, and this persisted on multivariable analysis (SHR 2.86, 95% CI 1.36-6.04) after considering relevant covariates, including cardiovascular risk scores, which were not independent predictors. Of the non-invasive indicators of fibrosis, the NAFLD fibrosis score was the only independent predictor of cardiovascular disease. Other histologic features, including steatohepatitis, were not associated with incident cardiovascular disease. CONCLUSIONS: In adults with biopsy-proven NAFLD, advanced fibrosis on biopsy and higher NAFLD fibrosis score were significant and independent predictors of incident cardiovascular disease, even after considering traditional risk factors and cardiovascular risk scores. These findings should be considered when evaluating NAFLD patients for primary prevention of cardiovascular disease, and further evaluation into the link between advanced fibrosis and cardiovascular disease is needed.

Molecular Magnetic Resonance Imaging of Fibrin Deposition in the Liver as an Indicator of Tissue Injury and Inflammation.

RATIONALE AND OBJECTIVES: Liver inflammation is associated with nonalcoholic steatohepatitis and other pathologies, but noninvasive methods to assess liver inflammation are limited. Inflammation causes endothelial disruption and leakage of plasma proteins into the interstitial space and can result in extravascular coagulation with fibrin deposition. Here we assess the feasibility of using the established fibrin-specific magnetic resonance probe EP-2104R for the noninvasive imaging of fibrin as a marker of liver inflammation. METHODS: Weekly 100 mg/kg diethylnitrosamine (DEN) dosing was used to generate liver fibrosis in male rats; control animals received vehicle. Magnetic resonance imaging at 1.5 T with EP-2104R, a matched non-fibrin-binding control linear peptide, or the collagen-specific probe EP-3533 was performed at 1 day or 7 days after the last DEN administration. Imaging data were compared with quantitative histological measures of fibrosis and inflammation. RESULTS: After 4 or 5 DEN administrations, the liver becomes moderately fibrotic, and fibrosis is the same if the animal is killed 1 day (Ishak score, 3.62 ± 0.31) or 7 days (Ishak score, 3.82 ± 0.25) after the last DEN dose, but inflammation is significantly higher at 1 day compared with 7 days after the last DEN dose (histological activity index from 0-4, 3.54 ± 0.14 vs 1.61 ± 0.16, respectively; P < 0.0001). Peak EP-2104R signal enhancement was significantly higher in animals imaged at 1 day post-DEN compared with 7 days post-DEN or control rats (29.0% ± 3.2% vs 22.4% ± 2.0% vs 17.0% ± 0.2%, respectively; P = 0.017). Signal enhancement with EP-2104R was significantly higher than control linear peptide at 1 day post-DEN but not at 7 days post-DEN indicating specific fibrin binding during the inflammatory phase. Collagen molecular magnetic resonance with EP-3533 showed equivalent T1 change when imaging rats 1 day or 7 days post-DEN, consistent with equivalent fibrosis. CONCLUSIONS: EP-2104R can specifically detect fibrin associated with inflammation in a rat model of liver inflammation and fibrosis.

Cholangiolar pattern and albumin in situ hybridisation enable a diagnosis of intrahepatic cholangiocarcinoma.

AIMS: The histological distinction of intrahepatic cholangiocarcinoma (ICC) from metastatic adenocarcinoma remains a challenge. The primary goal was to evaluate the diagnostic value of morphology and albumin expression in the diagnosis of ICC. METHODS: We evaluated morphological patterns in 120 ICCs and 677 non-hepatic adenocarcinomas and performed in situ hybridisation (ISH) stain for albumin in the former cohort (retrospective cohort). We also identified 119 samples from primary and metastatic lesions, the validation cohort, in which albumin ISH was performed as part of the diagnostic workup. Targeted sequencing was performed on selected cases. We also mined existing expression profiling data including cases from The Cancer Genome Atlas (TCGA) (41 760 unique samples). RESULTS: In the retrospective cohort, 45% of ICCs and <1% of non-hepatic adenocarcinomas showed a cholangiolar pattern; albumin ISH was positive in 93% of ICCs with significant intratumorous heterogeneity. In the validation cohort, 29% of ICCs showed a cholangiolar pattern and 88% expressed albumin, while all metastatic non-hepatic neoplasms were negative (n=37) (sensitivity 88% and specificity 100%). Targetable genetic alterations (IDH mutations and FGFR2 fusions) were identified in 31% of ICCs (10 of 32). An analysis of the TCGA data validated the specificity of the albumin assay. CONCLUSIONS: The cholangiolar pattern and albumin RNA ISH distinguishes ICC from metastatic adenocarcinoma with high specificity. Given the high prevalence of targetable mutations in ICC, albumin RNA ISH is an essential component in the workup of tumours of uncertain origin. A specific diagnosis of ICC could trigger molecular testing and uncover targetable genetic alterations.

Ablation of Hepatocyte Smad1, Smad5, and Smad8 Causes Severe Tissue Iron Loading and Liver Fibrosis in Mice.

A failure of iron to appropriately regulate liver hepcidin production is central to the pathogenesis of hereditary hemochromatosis. SMAD1/5 transcription factors, activated by bone morphogenetic protein (BMP) signaling, are major regulators of hepcidin production in response to iron; however, the role of SMAD8 and the contribution of SMADs to hepcidin production by other systemic cues remain uncertain. Here, we generated hepatocyte Smad8 single (Smad8fl/fl ;Alb-Cre+ ), Smad1/5/8 triple (Smad158;Alb-Cre+ ), and littermate Smad1/5 double (Smad15;Alb-Cre+ ) knockout mice to investigate the role of SMAD8 in hepcidin and iron homeostasis regulation and liver injury. We found that Smad8;Alb-Cre+ mice exhibited no iron phenotype, whereas Smad158;Alb-Cre+ mice had greater iron overload than Smad15;Alb-Cre+ mice. In contrast to the sexual dimorphism reported for wild-type mice and other hemochromatosis models, hepcidin deficiency and extrahepatic iron loading were similarly severe in Smad15;Alb-Cre+ and Smad158;Alb-Cre+ female compared with male mice. Moreover, epidermal growth factor (EGF) failed to suppress hepcidin in Smad15;Alb-Cre+ hepatocytes. Conversely, hepcidin was still increased by lipopolysaccharide in Smad158;Alb-Cre+ mice, although lower basal hepcidin resulted in lower maximal hepcidin. Finally, unlike most mouse hemochromatosis models, Smad158;Alb-Cre+ developed liver injury and fibrosis at 8 weeks. Liver injury and fibrosis were prevented in Smad158;Alb-Cre+ mice by a low-iron diet and were minimal in iron-loaded Cre- mice. Conclusion: Hepatocyte Smad1/5/8 knockout mice are a model of hemochromatosis that encompasses liver injury and fibrosis seen in human disease. These mice reveal the redundant but critical role of SMAD8 in hepcidin and iron homeostasis regulation, establish a requirement for SMAD1/5/8 in hepcidin regulation by testosterone and EGF but not inflammation, and suggest a pathogenic role for both iron loading and SMAD1/5/8 deficiency in liver injury and fibrosis.

Phospholipase A2 receptor-associated membranous nephropathy in a patient with IgG4-related disease: A case report.

RATIONALE: IgG4-related disease (IgG4-RD) is a multiorgan disease of unestablished prevalence that is characterized histopathologically by a dense lymphoplasmacytic infiltrate enriched with IgG4-expressing plasma cells and associated with storiform fibrosis. Tubulointerstitial nephritis (TIN) is the most common renal manifestation of IgG4-RD, but membranous nephropathy (MN) has also been described and often occurs in the context of concurrent TIN. Patients with IgG4-related MN have been characteristically negative for autoantibodies to the phospholipase A2 receptor (PLA2R). PATIENT CONCERNS: A 45-year-old man presented with abdominal pain and lower extremity edema. DIAGNOSIS: Histopathological evaluation of pancreas and liver biopsies established a diagnosis of IgG4-RD. Renal biopsy confirmed a diagnosis of PLA2R-associated MN without evidence of concurrent TIN. INTERVENTIONS: The patient was treated with rituximab, a short course of low-dose, oral cyclophosphamide, and a rapid glucocorticoid taper. OUTCOMES: The patient achieved remission of MN after 8 months of therapy and maintained remission of IgG4-RD. LESSONS: PLA2R-associated MN may be a rare manifestation of IgG4-RD. Systematic evaluation of larger cohorts of IgG4-RD patients for the presence of PLA2R autoantibodies and the investigation of PLA2R-associated MN cohorts for evidence of IgG4-RD would facilitate the understanding of the nature of the relationship between these observations.