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. (HEPATOLOGY 2012;56:1971–1982)
Evolution and epidemic spread of SARS-CoV-2 in Brazil Candido, Darlan S; Claro, Ingra M; de Jesus, Jaqueline G ...
Science (American Association for the Advancement of Science),
09/2020, Letnik:
369, Številka:
6508
Journal Article
Recenzirano
Odprti dostop
Brazil currently has one of the fastest-growing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) epidemics in the world. Because of limited available data, assessments of the impact of ...nonpharmaceutical interventions (NPIs) on this virus spread remain challenging. Using a mobility-driven transmission model, we show that NPIs reduced the reproduction number from >3 to 1 to 1.6 in São Paulo and Rio de Janeiro. Sequencing of 427 new genomes and analysis of a geographically representative genomic dataset identified >100 international virus introductions in Brazil. We estimate that most (76%) of the Brazilian strains fell in three clades that were introduced from Europe between 22 February and 11 March 2020. During the early epidemic phase, we found that SARS-CoV-2 spread mostly locally and within state borders. After this period, despite sharp decreases in air travel, we estimated multiple exportations from large urban centers that coincided with a 25% increase in average traveled distances in national flights. This study sheds new light on the epidemic transmission and evolutionary trajectories of SARS-CoV-2 lineages in Brazil and provides evidence that current interventions remain insufficient to keep virus transmission under control in this country.
Hepatocellular carcinoma (HCC) is the second leading cause of cancer death worldwide. Several types of chronic liver disease predispose to HCC, and several different signalling pathways have been ...implicated in its pathogenesis, but no common molecular event has been identified. Ca
signalling regulates the proliferation of both normal hepatocytes and liver cancer cells, so we investigated the role of intracellular Ca
release channels in HCC.
Expression analyses of the type 3 isoform of the inositol 1, 4, 5-trisphosphate receptor (ITPR3) in human liver samples, liver cancer cells and mouse liver were combined with an evaluation of DNA methylation profiles of ITPR3 promoter in HCC and characterisation of the effects of ITPR3 expression on cellular proliferation and apoptosis. The effects of
ITPR3 expression on hepatocyte calcium signalling and liver growth were evaluated in mice.
ITPR3 was absent or expressed in low amounts in hepatocytes from normal liver, but was expressed in HCC specimens from three independent patient cohorts, regardless of the underlying cause of chronic liver disease, and its increased expression level was associated with poorer survival. The
gene was heavily methylated in control liver specimens but was demethylated at multiple sites in specimens of patient with HCC. Administration of a demethylating agent in a mouse model resulted in ITPR3 expression in discrete areas of the liver, and Ca
signalling was enhanced in these regions. In addition, cell proliferation and liver regeneration were enhanced in the mouse model, and deletion of
from human HCC cells enhanced apoptosis.
These results provide evidence that
expression of ITPR3 typically occurs in HCC and may play a role in its pathogenesis.
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.
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.
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.
Leprosy is an important cause of disability in the developing world. Early diagnosis is essential to allow for cure and to interrupt transmission of this infection. MicroRNAs (miRNAs) are important ...factors for host-pathogen interaction and they have been identified as biomarkers for various infectious diseases. The expression profile of 377 microRNAs were analyzed by TaqMan low-density array (TLDA) in skin lesions of tuberculoid and lepromatous leprosy patients as well as skin specimens from healthy controls. In a second step, 16 microRNAs were selected for validation experiments with reverse transcription-quantitative PCR (qRT-PCR) in skin samples from new individuals. Principal-component analysis followed by logistic regression model and receiver operating characteristic (ROC) curve analyses were performed to evaluate the diagnostic potential of selected miRNAs. Four patterns of differential expression were identified in the TLDA experiment, suggesting a diagnostic potential of miRNAs in leprosy. After validation experiments, a combination of four miRNAs (miR-101, miR-196b, miR-27b, and miR-29c) was revealed as able to discriminate between healthy control and leprosy patients with 80% sensitivity and 91% specificity. This set of miRNAs was also able to discriminate between lepromatous and tuberculoid patients with a sensitivity of 83% and 80% specificity. In this work, it was possible to identify a set of miRNAs with good diagnostic potential for leprosy.
Abstract
Long-term infection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) represents a challenge to virus dispersion and the control of coronavirus disease 2019 (COVID-19) ...pandemic. The reason why some people have prolonged infection and how the virus persists for so long are still not fully understood. Recent studies suggested that the accumulation of intra-host single nucleotide variants (iSNVs) over the course of the infection might play an important role in persistence as well as emergence of mutations of concern. For this reason, we aimed to investigate the intra-host evolution of SARS-CoV-2 during prolonged infection. Thirty-three patients who remained reverse transcription polymerase chain reaction (RT-PCR) positive in the nasopharynx for on average 18 days from the symptoms onset were included in this study. Whole-genome sequences were obtained for each patient at two different time points. Phylogenetic, populational, and computational analyses of viral sequences were consistent with prolonged infection without evidence of coinfection in our cohort. We observed an elevated within-host genomic diversity at the second time point samples positively correlated with cycle threshold (Ct) values (lower viral load). Direct transmission was also confirmed in a small cluster of healthcare professionals that shared the same workplace by the presence of common iSNVs. A differential accumulation of missense variants between the time points was detected targeting crucial structural and non-structural proteins such as Spike and helicase. Interestingly, longitudinal acquisition of iSNVs in Spike protein coincided in many cases with SARS-CoV-2 reactive and predicted T cell epitopes. We observed a distinguishing pattern of mutations over the course of the infection mainly driven by increasing A→U and decreasing G→A signatures. G→A mutations may be associated with RNA-editing enzyme activities; therefore, the mutational profiles observed in our analysis were suggestive of innate immune mechanisms of the host cell defense. Therefore, we unveiled a dynamic and complex landscape of host and pathogen interaction during prolonged infection of SARS-CoV-2, suggesting that the host’s innate immunity shapes the increase of intra-host diversity. Our findings may also shed light on possible mechanisms underlying the emergence and spread of new variants resistant to the host immune response as recently observed in COVID-19 pandemic.
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.
Sepsis can lead to long-term cognitive changes, including memory and learning deficits, which are known as septic encephalopathy (SE). SE also includes behavioral changes. The underlying mechanism of ...SE is unknown, and several mechanisms have been proposed. This study investigated late anxiety-like behavior, serum cytokine levels and brain cytokine production in C57BL/6 mice subjected to polymicrobial sepsis induced by sublethal cecum ligature and puncture (CLP). Anxiety-like behavior and locomotor activity were assessed in mice 10 days after sham operation or CLP procedure using the elevated plus maze, contextual fear conditioning, and open field test. Brain and serum concentrations of the cytokines TNF-α, IFN-γ, IL-1β, IL-6, and IL-10 were determined by ELISA. We found that mice subjected to polymicrobial sepsis presented anxiety-like behavior, which was accompanied by increased serum TNF-α and brain TNF-α, IFN-γ, IL-1β, and IL-6 levels, 10 days after the surgical procedure. These findings suggest an involvement of central nervous system inflammatory mediators in the anxiety-like symptoms found in SE.
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.
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.
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.
ABSTRACT Introduction: Endothelial dysfunction may contribute to hypercoagulable and inflammation states presents in renal transplant, chronic kidney disease (CKD) and its causes. These disorders can ...be evaluated by markers, such as thrombomodulin (TM), von Willebrand factor (vWF) and interleukin 6 (IL-6). Objectives: The aim of this study was to assess TM, vWF and IL-6 in renal transplant recipients (RTR) and associate their plasma levels with primary cause of end-stage renal disease (ESRD) and allograft function. Methods: 160 RTR were grouped according to the primary cause of CKD (G1: glomerulopathy; G2: hypertensive nephrosclerosis; G3: diabetic nephropathy; and G4: other causes/unknown etiology); creatinine plasma levels (C1 < 1.4 and C2 ≥ 1.4 mg/dl); and the estimated glomerular filtration rate (eGFR) (R1< 60 and R2 ≥ 60 ml/min/1.73 m2). TM and vWF were determined by the enzyme-linked immunosorbent assay (ELISA) and IL-6 by flow cytometry. The results were presented as median, minimum and maximum; p-value < 0.05 was considered statistically significant. Results: TM levels were significantly higher in the G1 group compared to the others (G1: 8.38; G2: 5.51; G3: 5.88; G4: 6.33 ng/ml, p < 0.0001), and in the R1 group compared to R2 (R1: 6.65; R2: 6.19 ng/ml, p = 0.02). The concentration of IL-6, measured by the mean fluorescence intensity, was higher in C2 group when compared to C1 (C1: 7.9; C2: 13.35, p = 0.03). There was no difference in vWF levels among groups. TM correlated positively with IL-6 and creatinine, and negatively with eGFR. IL-6 also correlated positively with vWF. Conclusion: TM and IL-6 can be identified as potential markers for evaluating renal graft function. TM was more related to the primary cause of CKD compared to vWF and IL-6.
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