Succinate causes pathological cardiomyocyte hypertrophy through GPR91 activation

Background\ud Succinate is an intermediate of the citric acid cycle as well as an extracellular circulating molecule, whose receptor, G protein-coupled receptor-91 (GPR91), was recently identified and characterized in several tissues, including heart. Because some pathological conditions such as ischemia increase succinate blood levels, we investigated the role of this metabolite during a heart ischemic event, using human and rodent models.\ud \ud \ud Results\ud We found that succinate causes cardiac hypertrophy in a GPR91 dependent manner. GPR91 activation triggers the phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2), the expression of calcium/calmodulin dependent protein kinase IIδ (CaMKIIδ) and the translocation of histone deacetylase 5 (HDAC5) into the cytoplasm, which are hypertrophic-signaling events. Furthermore, we found that serum levels of succinate are increased in patients with cardiac hypertrophy associated with acute and chronic ischemic diseases.\ud \ud \ud Conclusions\ud These results show for the first time that succinate plays an important role in cardiomyocyte hypertrophy through GPR91 activation, and extend our understanding of how ischemia can induce hypertrophic cardiomyopathy.CAPESFAPEMIG (Pronex)INCT- Carbon NanotubesCNPqHHM

MQL Strategies Applied in Ti-6Al-4V Alloy Milling—Comparative Analysis between Experimental Design and Artificial Neural Networks

This paper presents a study of the Ti-6Al-4V alloy milling under different lubrication conditions, using the minimum quantity lubrication approach. The chosen material is widely used in the industry due to its properties, although they present difficulties in terms of their machinability. A minimum quantity lubrication (MQL) prototype valve was built for this purpose, and machining followed a previously defined experimental design with three lubrication strategies. Speed, feed rate, and the depth of cut were considered as independent variables. As design-dependent variables, cutting forces, torque, and roughness were considered. The desirability optimization function was used in order to obtain the best input data indications, in order to minimize cutting and roughness efforts. Supervised artificial neural networks of the multilayer perceptron type were created and tested, and their responses were compared statistically to the results of the factorial design. It was noted that the variables that most influenced the machining-dependent variables were the feed rate and the depth of cut. A lower roughness value was achieved with MQL only with the use of cutting fluid with graphite. Statistical analysis demonstrated that artificial neural network and the experimental design predict similar results

Expression of MAPK and PI3K/AKT/mTOR Proteins according to the Chronic Liver Disease Etiology in Hepatocellular Carcinoma

Aims. Chronic liver disease (CLD) of different etiologies leads to hepatocellular carcinoma (HCC) by multiple mechanisms that may be translated into clinicopathological differences. We evaluated the tissue expression of the MAPK and PI3K/Akt/mTOR pathway proteins and their association with long-term outcome and other parameters, according to the etiology of the CLD, in HCC patients. Methods. Clinicopathological data from 80 patients who underwent orthotopic liver transplantation for HCC treatment in a Brazilian referral center were compared according to CLD etiology. Event (tumor recurrence or death from any cause) occurrence and event-free survival (EFS) were analyzed. Pathway protein expression was assessed by immunohistochemistry (IHQ) in both tumor and underlying cirrhosis and by RT-PCR in tumor tissue. Results. Strong expression (SE) of KRAS was more frequent in tumors arising from viral (26.8%) than the nonviral group of liver disease (7.7%, p=0.024) and also than cirrhotic parenchyma (0%, p=0.004). SE of PI3K was more frequent in tumor than in cirrhosis (p=0.048, p<0.01), without differences in its tumor expression among etiologic groups p=0.111. mRNA of ERK, PI3K, and BRAF was expressed in the tumor, without differences between CLD etiologies, and there was no association with IHQ findings. Older age and microvascular invasion (MIV) were the only parameters independently associated with the event. MIV was also associated with shorter EFS. Conclusions. Hepatitis B and C virus can lead to HCC by different mechanisms compared with nonviral hepatopathy. KRAS and PI3K may have a role in carcinogenesis. The prognostic and therapeutic implications need to be investigated

Chemokines and mitochondrial products activate neutrophils to amplify organ injury during mouse acute liver failure

UNLABELLED: Acetaminophen (APAP) is a safe analgesic and antipyretic drug. However, APAP overdose leads to massive hepatocyte death. Cell death during APAP toxicity occurs by oncotic necrosis, in which the release of intracellular contents can elicit a reactive inflammatory response. We have previously demonstrated that an intravascular gradient of chemokines and mitochondria-derived formyl peptides collaborate to guide neutrophils to sites of liver necrosis by CXC chemokine receptor 2 (CXCR2) and formyl peptide receptor 1 (FPR1), respectively. Here, we investigated the role of CXCR2 chemokines and mitochondrial products during APAP-induced liver injury and in liver neutrophil influx and hepatotoxicity. During APAP overdose, neutrophils accumulated into the liver, and blockage of neutrophil infiltration by anti-granulocyte receptor 1 depletion or combined CXCR2-FPR1 antagonism significantly prevented hepatotoxicity. In agreement with our in vivo data, isolated human neutrophils were cytotoxic to HepG2 cells when cocultured, and the mechanism of neutrophil killing was dependent on direct contact with HepG2 cells and the CXCR2-FPR1-signaling pathway. Also, in mice and humans, serum levels of both mitochondrial DNA (mitDNA) and CXCR2 chemokines were higher during acute liver injury, suggesting that necrosis products may reach remote organs through the circulation, leading to a systemic inflammatory response. Accordingly, APAP-treated mice exhibited marked systemic inflammation and lung injury, which was prevented by CXCR2-FPR1 blockage and Toll-like receptor 9 (TLR9) absence (TLR9(-/-) mice). CONCLUSION: Chemokines and mitochondrial products (e.g., formyl peptides and mitDNA) collaborate in neutrophil-mediated injury and systemic inflammation during acute liver failure. Hepatocyte death is amplified by liver neutrophil infiltration, and the release of necrotic products into the circulation may trigger a systemic inflammatory response and remote lung injury.status: publishe

Assessment of loose and adhered urban street sediments and trace metals: a study in the city of Po double dagger os de Caldas, Brazil

This study aims to quantify and characterise sediments accumulated in the street gutters in an urban area of Po double dagger os de Caldas, Brazil. The main research questions are: What type of urban areas, e.g. those under construction, produce most sediments and what are the main characteristics of such sediments? What differences, e.g. granulometry, can be found in loose and adhered sediments? What trace metals can be found in the sediments?Fieldwork was carried out in a residential area of Po double dagger os de Caldas, Brazil. Ten samplings were conducted between May and August 2013 to collect sediments from road gutters. The collected sediments were then divided into 'loose' and 'adhered', depending on whether they were collected in a first, gentle, sweeping with soft bristled brush or in a subsequent sweeping with a stiff bristled brush. Granulometric curves were drawn for both types of sediments. Fine sediment analyses (aecurrency sign63 mu m) were performed on samples from the last five samplings. Two techniques were used to look for trace elements: energy dispersive X-ray fluorescence (EDXRF) and inductively coupled plasma-atomic emission spectrometry (ICP-AES).Larger amounts of sediments were collected after lower intensity rainfall events. Higher intensity events seemed to wash the sediments away. A correlation was found between areas under construction and sediment mass production. A characteristic range of granulometries (medium sand), found in our study is in accordance with studies by other authors. An important presence of heavy metals (Cr, Cd, Pb, Zn, Ni and Cu) was detected and characterised. As and Sn were also detected even though they are not often mentioned in the literature on urban soil pollutants.Areas under construction were found to produce more sediments than other areas. The trace metals found in highest concentrations were Pb and As. The heavy metal concentration decreases after wet periods, showing that they are carried by runoff. It is expected that this study may serve as an input for establishing diffuse pollution control and mitigation strategies for the accumulation of pollutants in the urban environment

Altered responsiveness to extracellular ATP enhances acetaminophen hepatotoxicity

BACKGROUND: Adenosine triphosphate (ATP) is secreted from hepatocytes under physiological conditions and plays an important role in liver biology through the activation of P2 receptors. Conversely, higher extracellular ATP concentrations, as observed during necrosis, trigger inflammatory responses that contribute to the progression of liver injury. Impaired calcium (Ca2+) homeostasis is a hallmark of acetaminophen (APAP)-induced hepatotoxicity, and since ATP induces mobilization of the intracellular Ca2+ stocks, we evaluated if the release of ATP during APAP-induced necrosis could directly contribute to hepatocyte death. RESULTS: APAP overdose resulted in liver necrosis, massive neutrophil infiltration and large non-perfused areas, as well as remote lung inflammation. In the liver, these effects were significantly abrogated after ATP metabolism by apyrase or P2X receptors blockage, but none of the treatments prevented remote lung inflammation, suggesting a confined local contribution of purinergic signaling into liver environment. In vitro, APAP administration to primary mouse hepatocytes and also HepG2 cells caused cell death in a dose-dependent manner. Interestingly, exposure of HepG2 cells to APAP elicited significant release of ATP to the supernatant in levels that were high enough to promote direct cytotoxicity to healthy primary hepatocytes or HepG2 cells. In agreement to our in vivo results, apyrase treatment or blockage of P2 receptors reduced APAP cytotoxicity. Likewise, ATP exposure caused significant higher intracellular Ca2+ signal in APAP-treated primary hepatocytes, which was reproduced in HepG2 cells. Quantitative real time PCR showed that APAP-challenged HepG2 cells expressed higher levels of several purinergic receptors, which may explain the hypersensitivity to extracellular ATP. This phenotype was confirmed in humans analyzing liver biopsies from patients diagnosed with acute hepatic failure. CONCLUSION: We suggest that under pathological conditions, ATP may act not only an immune system activator, but also as a paracrine direct cytotoxic DAMP through the dysregulation of Ca2+ homeostasis.status: publishe

Yellow fever virus is susceptible to sofosbuvir both in vitro and in vivo.

Yellow fever virus (YFV) is a member of the Flaviviridae family. In Brazil, yellow fever (YF) cases have increased dramatically in sylvatic areas neighboring urban zones in the last few years. Because of the high lethality rates associated with infection and absence of any antiviral treatments, it is essential to identify therapeutic options to respond to YFV outbreaks. Repurposing of clinically approved drugs represents the fastest alternative to discover antivirals for public health emergencies. Other Flaviviruses, such as Zika (ZIKV) and dengue (DENV) viruses, are susceptible to sofosbuvir, a clinically approved drug against hepatitis C virus (HCV). Our data showed that sofosbuvir docks onto YFV RNA polymerase using conserved amino acid residues for nucleotide binding. This drug inhibited the replication of both vaccine and wild-type strains of YFV on human hepatoma cells, with EC50 values around 5 μM. Sofosbuvir protected YFV-infected neonatal Swiss mice and adult type I interferon receptor knockout mice (A129-/-) from mortality and weight loss. Because of its safety profile in humans and significant antiviral effects in vitro and in mice, Sofosbuvir may represent a novel therapeutic option for the treatment of YF. Key-words: Yellow fever virus; Yellow fever, antiviral; sofosbuvir