Arsenic accumulation in lettuce (Lactuca sativa L.) and broad bean (Vicia faba L.) crops and its potential risk for human consumption

Exposure to arsenic (As) is considered one of the primary health risks humans face worldwide. This study was conducted to determine As absorption by broad beans and lettuce crops grown in soil with As contents and irrigated with water contaminated with this toxic element, in Pastos Chicos, Jujuy (Argentina). Total dry biomass (TDB) and total As were determined in soils, roots, leaves, pods and seeds. These data were used to determine several parameters, such as translocation (TF) and bioconcentration (BCF) factors, target hazard quotient (THQ), and carcinogenic risk (CR). Broad bean plants had the lowest biomass production when exposed to As in irrigation water and soil. Lettuce plants presented TDB reductions of 33.3 and 42.8% when grown in soil polluted with As, and in control soil under irrigation with contaminated water, respectively. The presence of this toxicant in broad bean seeds and lettuce leaves (edible parts) exceeded the limits established by Código Alimentario Argentino, i.e. 0.10 and 0.30 mg/kg, respectively. THQ values for lettuce leaves were higher than 1, the same as those for broad bean seeds when grown in soil with As contents and irrigated with arsenic-contaminated water, thus suggesting that consumers would run significant risks when consuming these vegetables. Furthermore, this type of exposure to As implied a CR that exceeded the acceptable 1 × 10−4 risk level. Hence, we may conclude that consuming lettuce and broad beans grown at the evaluated site brings about considerable health risks for local residents.Fil: Yanez, Luciano Matias. Universidad Nacional de Jujuy. Facultad de Ciencias Agrarias; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta; ArgentinaFil: Alfaro, J. A.. Universidad Nacional de Jujuy. Facultad de Ciencias Agrarias; ArgentinaFil: Avila Carreras, Natalia Maria Elisa. Universidad Nacional de Jujuy. Facultad de Ciencias Agrarias; ArgentinaFil: Bovi Mitre, G.. Universidad Nacional de Jujuy. Facultad de Ciencias Agrarias; Argentin

Post-translational deregulation of YAP1 is genetically controlled in rat liver cancer and determines the fate and stem-like behavior of the human disease

Previous studies showed that YAP1 is over-expressed in hepatocellular carcinoma (HCC). Here we observed higher expression of Yap1/Ctgf axis in dysplastic nodules and HCC chemically-induced in F344 rats, genetically susceptible to hepatocarcinogenesis, than in lesions induced in resistant BN rats. In BN rats, highest increase in Yap1-tyr357, p73 phosphorylation and Caspase 3 cleavage occurred. In human HCCs with poorer prognosis ( 3 years survival; HCCB). In the latter, higher levels of phosphorylated YAP1-ser127, YAP1-tyr357 and p73, YAP1 ubiquitination, and Caspase 3 cleavage occurred. Expression of stemness markers NANOG, OCT-3/4, and CD133 were highest in HCCP and correlated with YAP1 and YAP1-TEAD levels. In HepG2, Huh7, and Hep3B cells, forced YAP1 over-expression led to stem cell markers expression and increased cell viability, whereas inhibition of YAP1 expression by specific siRNA, or transfection of mutant YAP1 which does not bind to TEAD, induced opposite alterations. These changes were associated, in Huh7 cells transfected with YAP1 or YAP1 siRNA, with stimulation or inhibition of cell migration and invasivity, respectively. Furthermore, transcriptome analysis showed that YAP1 transfection in Huh7 cells induces over-expression of genes involved in tumor stemness. In conclusion, Yap1 post-translational modifications favoring its ubiquitination and apoptosis characterize HCC with better prognosis, whereas conditions favoring the formation of YAP1-TEAD complexes are associated with aggressiveness and acquisition of stemness features by HCC cells

Cardiotrophin-1 defends the liver against ischemia-reperfusion injury and mediates the protective effect of ischemic preconditioning

Ischemia-reperfusion (I/R) liver injury occurs when blood flow is restored after prolonged ischemia. A short interruption of blood flow (ischemic preconditioning [IP]) induces tolerance to subsequent prolonged ischemia through ill-defined mechanisms. Cardiotrophin (CT)-1, a cytokine of the interleukin-6 family, exerts hepatoprotective effects and activates key survival pathways like JAK/STAT3. Here we show that administration of CT-1 to rats or mice protects against I/R liver injury and that CT-1–deficient mice are exceedingly sensitive to this type of damage. IP markedly reduced transaminase levels and abrogated caspase-3 and c-Jun–NH2-terminal kinase activation after I/R in normal mice but not in CT-1–null mice. Moreover, the protective effect afforded by IP was reduced by previous administration of neutralizing anti–CT-1 antibody. Prominent STAT3 phosphorylation in liver tissue was observed after IP plus I/R in normal mice but not in CT-1–null mice. Oxidative stress, a process involved in IP-induced hepatoprotection, was found to stimulate CT-1 release from isolated hepatocytes. Interestingly, brief ischemia followed by short reperfusion caused mild serum transaminase elevation and strong STAT3 activation in normal and IL-6–deficient mice, but failed to activate STAT3 and provoked marked hypertransaminasemia in CT-1–null animals. In conclusion, CT-1 is an essential endogenous defense of the liver against I/R and is a key mediator of the protective effect induced by IP

The search for novel diagnostic and prognostic biomarkers in cholangiocarcinoma

[EN] The poor prognosis of cholangiocarcinoma (CCA) is in part due to late diagnosis, which is currently achieved by a combination of clinical, radiological and histological approaches. Available biomarkers determined in serum and biopsy samples to assist in CCA diagnosis are not sufficiently sensitive and specific. Therefore, the identification of new biomarkers, preferably those obtained by minimally invasive methods, such as liquid biopsy, is important. The development of innovative technologies has permitted to identify a significant number of genetic, epigenetic, proteomic and metabolomic CCA features with potential clinical usefulness in early diagnosis, prognosis or prediction of treatment response. Potential new candidates must be rigorously evaluated prior to entering routine clinical application. Unfortunately, to date, no such biomarker has achieved validation for these purposes. This review is an up-to-date of currently used biomarkers and the candidates with promising characteristics that could be included in the clinical practice in the next future. This article is part of a Special Issue entitled: Cholangiocytes in Health and Disease edited by Jesus Banales, Marco Marzioni, Nicholas LaRusso and Peter Jansen

Methylthioadenosine reverses brain autoimmune disease

OBJECTIVE: To assess the immunomodulatory activity of methylthioadenosine (MTA) in rodent experimental autoimmune encephalomyelitis (EAE) and in patients with multiple sclerosis. METHODS: We studied the effect of intraperitoneal MTA in the acute and chronic EAE model by quantifying clinical and histological scores and by performing immunohistochemistry stains of the brain. We studied the immunomodulatory effect of MTA in lymphocytes from EAE animals and in peripheral blood mononuclear cells from healthy control subjects and multiple sclerosis patients by assessing cell proliferation and cytokine gene expression, by real-time polymerase chain reaction, and by nuclear factor-kappaB modulation by Western blot. RESULTS: We found that MTA prevents acute EAE and, more importantly, reverses chronic-relapsing EAE. MTA treatment markedly inhibited brain inflammation and reduced brain damage. Administration of MTA suppressed T-cell activation in vivo and in vitro, likely through a blockade in T-cell signaling resulting in the prevention of inhibitor of kappa B (IkappaB-alpha) degradation and in the impaired activation transcription factor nuclear factor-kappaB. Indeed, MTA suppressed the production of proinflammatory genes and cytokines (interferon-gamma, tumor necrosis factor-alpha, and inducible nitric oxide synthase) and increased the production of antiinflammatory cytokines (interleukin-10). INTERPRETATION: MTA has a remarkable immunomodulatory activity and may be beneficial for multiple sclerosis and other autoimmune diseases

Toll-like receptor-4 expression by hepatic progenitor cells and biliary epithelial cells in HCV-related chronic liver disease

Background. Toll-like receptor-4 (TLR4) is a transmembrane pattern recognition receptor that plays a key role in innate immunity by triggering inflammatory responses to Gram negative bacteria lipopolysaccharide (LPS) (1). Since liver is the main clearance organ for LPS, which is excreted in large amounts in the bile (2), it is not surprising that TLR4 has been involved in the pathogenesis of most liver diseases (3). Numerous evidences suggest a role for TLR4 in the pathogenesis of chronic hepatitis C virus (HCV) infection (4) and hepatic fibrosis (5), but the localization and level of TLR4 expression in the liver of patients with hepatitis C have never been investigated. Aim and methods. We aimed to evaluate, by means of immunohistochemistry (IHC) and real-time polymerase chain reaction (rt-PCR), hepatic TLR4 expression in patients with chronic HCV infection. Sixty-one patients with chronic HCV infection, and 12 controls free of liver disease, were included in the study. Each case was analyzed by IHC for TLR4, α–smooth muscle actin (αSMA) and cytokeratin-7 (CK-7), and a subgroup of patients and all controls by rt-PCR for TLR4. A score of activation of portal/septal myofibroblasts and lobular hepatic stellate cells (HSCs) was evaluated by IHC for α-SMA, whereas IHC for CK-7 was analysed in order to count hepatic progenitor cells (HPCs), interlobular bile ducts and intermediate hepatocytes. Results. The parenchimal elements responsible for the highest TLR4 level of expression were HPCs and biliary epithelial cells (BECs) of interlobular bile ducts in the infected group. Double-labeling experiments with anti-TLR4, anti-CK7 and anti-CD133 confirmed this finding. TLR4-positive HPCs and interlobular bile ducts were significantly correlated with the stage of liver disease (p<0.001), the grade of inflammation (p<0.001), and with the activity of portal/septal myofibroblasts (p<0.001). Rt-PCR study confirmed an increased TLR4 expression in the 26 patients analyzed with respect to controls (p<0.001). TLR4 expression positively correlated with fibrosis (p<0.05) and inflammation (p<0.05). Conclusions. The expression of TLR4 in HPCs and BECs in HCV-related liver damage significantly correlates with inflammation, activation of portal/septal myofibroblasts and fibrosis. 1) Beutler. Nature 2004;430:257-63; 2) Van Bossuyt et al. J Hepatol 1988;7:325-37; 3) Seki et al. Hepatology 2008;48:322-35; 4) Machida et al. J Virol 2006;80:866-74. 5) Seki et al. Nat Med 2007;13:1324-32

Loss of c-Jun N-terminal Kinase 1 and 2 Function in Liver Epithelial Cells Triggers Biliary Hyperproliferation Resembling Cholangiocarcinoma

Targeted inhibition of the c-Jun N-terminal kinases (JNKs) has shown therapeutic potential in intrahepatic cholangiocarcinoma (CCA)-related tumorigenesis. However, the cell-type-specific role and mechanisms triggered by JNK in liver parenchymal cells during CCA remain largely unknown. Here, we aimed to investigate the relevance of JNK1 and JNK2 function in hepatocytes in two different models of experimental carcinogenesis, the dethylnitrosamine (DEN) model and in nuclear factor kappa B essential modulator (NEMO)(hepatocyte-specific knockout (Deltahepa)) mice, focusing on liver damage, cell death, compensatory proliferation, fibrogenesis, and tumor development. Moreover, regulation of essential genes was assessed by reverse transcription polymerase chain reaction, immunoblottings, and immunostainings. Additionally, specific Jnk2 inhibition in hepatocytes of NEMO(Deltahepa)/JNK1(Deltahepa) mice was performed using small interfering (si) RNA (siJnk2) nanodelivery. Finally, active signaling pathways were blocked using specific inhibitors. Compound deletion of Jnk1 and Jnk2 in hepatocytes diminished hepatocellular carcinoma (HCC) in both the DEN model and in NEMO(Deltahepa) mice but in contrast caused massive proliferation of the biliary ducts. Indeed, Jnk1/2 deficiency in hepatocytes of NEMO(Deltahepa) (NEMO(Deltahepa)/JNK(Deltahepa)) animals caused elevated fibrosis, increased apoptosis, increased compensatory proliferation, and elevated inflammatory cytokines expression but reduced HCC. Furthermore, siJnk2 treatment in NEMO(Deltahepa)/JNK1(Deltahepa) mice recapitulated the phenotype of NEMO(Deltahepa)/JNK(Deltahepa) mice. Next, we sought to investigate the impact of molecular pathways in response to compound JNK deficiency in NEMO(Deltahepa) mice. We found that NEMO(Deltahepa)/JNK(Deltahepa) livers exhibited overexpression of the interleukin-6/signal transducer and activator of transcription 3 pathway in addition to epidermal growth factor receptor (EGFR)-rapidly accelerated fibrosarcoma (Raf)-mitogen-activated protein kinase kinase (MEK)-extracellular signal-regulated kinase (ERK) cascade. The functional relevance was tested by administering lapatinib, which is a dual tyrosine kinase inhibitor of erythroblastic oncogene B-2 (ErbB2) and EGFR signaling, to NEMO(Deltahepa)/JNK(Deltahepa) mice. Lapatinib effectively inhibited cystogenesis, improved transaminases, and effectively blocked EGFR-Raf-MEK-ERK signaling. Conclusion: We define a novel function of JNK1/2 in cholangiocyte hyperproliferation. This opens new therapeutic avenues devised to inhibit pathways of cholangiocarcinogenesis

Recent Insights into the Pathogenesis of Acute Porphyria Attacks and Increasing Hepatic PBGD as an Etiological Treatment

Rare diseases, especially monogenic diseases, which usually affect a single target protein, have attracted growing interest in drug research by encouraging pharmaceutical companies to design and develop therapeutic products to be tested in the clinical arena. Acute intermittent porphyria (AIP) is one of these rare diseases. AIP is characterized by haploinsufficiency in the third enzyme of the heme biosynthesis pathway. Identification of the liver as the target organ and a detailed molecular characterization have enabled the development and approval of several therapies to manage this disease, such as glucose infusions, heme replenishment, and, more recently, an siRNA strategy that aims to down-regulate the key limiting enzyme of heme synthesis. Given the involvement of hepatic hemoproteins in essential metabolic functions, important questions regarding energy supply, antioxidant and detoxifying responses, and glucose homeostasis remain to be elucidated. This review reports recent insights into the pathogenesis of acute attacks and provides an update on emerging treatments aimed at increasing the activity of the deficient enzyme in the liver and restoring the physiological regulation of the pathway. While further studies are needed to optimize gene therapy vectors or large-scale production of liver-targeted PBGD proteins, effective protection of PBGD mRNA against the acute attacks has already been successfully confirmed in mice and large animals, and mRNA transfer technology is being tested in several clinical trials for metabolic diseases