Mitochondrial Mechanisms of Acetaminophen Hepatotoxicity

Acetaminophen (APAP) is a threshold hepatotoxicant whose overdose produces a fulminant hepatic necrosis. Therapeutic doses are non-hepatotoxic but high therapeutic dosing may induce hepatotoxicity in some vulnerable patients. The underlying mechanism of APAP hepatotoxicity involves mitochondrial dysfunction, including respiratory inhibition, mitochondrial oxidant stress, onset of the mitochondrial permeability transition (MPT) and loss of the mitochondrial membrane potential (ΔΨ). Iron-mediated reactive oxygen species (ROS) formation is essential in oxidative stress. Previous studies show that iron released from lysosomes is taken up into mitochondria during APAP hepatotoxicity, which triggers the MPT and cell killing. Here, my aim was to investigate mitochondrial mechanisms and the role of iron in hepatotoxicity in vitro and in vivo after various doses of APAP. Mouse hepatocytes and C57BL/6 mice were administered APAP in the presence and absence of NIM811 (MPT inhibitor), starch-desferal (lysosomally targeted iron chelator), Ru360 and minocycline (inhibitors of the mitochondrial Ca,Fe uniporter [MCFU], or Nacetylcysteine (NAC, an antioxidant). Necrotic cell killing was determined by propidium iodide (PI) fluorometry. Chelatable Fe2+, mitochondrial membrane potential and ROS were monitored by confocal/ multiphoton microscopy of different fluorophores. Liver injury was assessed by ALT release and liver necrosis. In vivo studies showed that high dose APAP (300 mg/kg) caused ALT release, liver necrosis, irreversible mitochondrial dysfunction and cell death. By contrast, low dose APAP causes reversible mitochondrial dysfunction associated with transient JNK activation and translocation to mitochondria of hepatocytes without ALT release or necrosis in vivo. NIM811 attenuated these changes at both low and high APAP, indicating that the MPT is the likely principal mechanism of mitochondrial dysfunction. In searching for the upstream inducer of MPT that may participate in APAP hepatotoxicity, we examined the role of iron. After exposure of hepatocytes to APAP, confocal/multiphoton microscopy showed that iron translocates from lysosomes into mitochondria both in vitro and in vivo. Mitochondria take up this Fe2+ via the mitochondrial MCFU to trigger formation of reactive oxygen species (ROS) and the MPT. The iron chelator, starch-desferal, and the MCFU inhibitors, Ru360 and minocycline, protected against APAP-induced liver injury. In addition, minocycline post-treatment at 4 h after APAP showed protection in vivo, whereas NAC was ineffective at this late time point. Taken together, the data suggest that release of chelatable Fe2+ from lysosomes followed by uptake into mitochondria via MCFU occurs during APAP hepatotoxicity, which in turn catalyzes ROS formation and triggers iron-dependent MPT and cell killing. The efficacy of minocycline posttreatment compared to NAC shows minocycline as a new therapeutic agent against APAP hepatotoxicity

A genomic-based approach to the understanding of the molecular biology of non-small cell lung cancer

EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Molecular characterization of feline astrovirus in domestic cats from Northeast China.

Feline astrovirus (FeAstV) which belonged to the genus Mamastrovirus was first identified in the feces of kittens with diarrhea in the USA in 1981 by electron microscopy, and had been reported in many countries. Presently, there are no any reports of the circulation of FeAstV in mainland China. We performed this study to investigate the apparent prevalence and genetic variability of FeAstV infected in cats in mainland China for the first time. We tested fecal samples of 105 cats with diarrhea and 92 asymptomatic cats in five cities in northeast China by RT-PCR targeting RNA-dependent RNA polymerase (RdRp) gene of FeAstV, and analyzed sequences variability and phylogenetic evolution based on the complete capsid gene of FeAstV strains obtained from positive samples. The overall prevalence of FeAstV was 23.4% (46/197) of which 38 were tested in cats with diarrhea (36.2%, 38/105) and 8 were in asymptomatic cats (8.7%, 8/92). Mixed infection with other enteroviruses including feline parvovirus (FPV), feline bocavirus (FBoV) and feline kobuvirus (FeKoV) was found in 38 FeAstV-positive samples. Phylogenetic analysis based on the complete capsid gene revealed all FeAstV strains were divided into two different groups with a 0.454±0.016 of mean amino acid genetic distance between two groups, suggesting that FeAstVs should be classified into two different genotype species. This study provided the first molecular evidence that FeAstV with considerable genetic diversity was circulating in northeast China, and analyzed genetic variability and classification of FeAstVs for the first time

Vessel co-option in primary human tumors and metastases: an obstacle to effective anti-angiogenic treatment?

Angiogenesis has been regarded as essential for tumor growth and progression. Studies of many human tumors, however, suggest that their microcirculation may be provided by nonsprouting vessels and that a variety of tumors can grow and metastasize without angiogenesis. Vessel co-option, where tumor cells migrate along the preexisting vessels of the host organ, is regarded as an alternative tumor blood supply. Vessel co-option may occur in many malignancies, but so far mostly reported in highly vascularized tissues such as brain, lung, and liver. In primary and metastatic lung cancer and liver metastasis from different primary origins, as much as 10–30% of the tumors are reported to use this alternative blood supply. In addition, vessel co-option is introduced as a potential explanation of antiangiogenic drug resistance, although the impact of vessel co-option in this clinical setting is still to be further explored. In this review we discuss tumor vessel co-option with specific examples of vessel cooption in primary and secondary tumors and a consideration of the clinical implications of this alternative tumor blood supply

Gene Signatures Stratify Computed Tomography Screening Detected Lung Cancer in High-Risk Populations

Background: Although screening programmes of smokers have detected resectable early lung cancers more frequently than expected, their efficacy in reducing mortality remains debatable. To elucidate the biological features of computed tomography (CT) screening detected lung cancer, we examined the mRNA signatures on tumours according to the year of detection, stage and survival. Methods: Gene expression profiles were analysed on 28 patients (INT–IEO training cohort) and 24 patients of Multicentre Italian Lung Detection (MILD validation cohort). The gene signatures generated from the training set were validated on the MILD set and a public deposited DNA microarray data set (GSE11969). Expression of selected genes and proteins was validated by real-time RT-PCR and immunohistochemistry. Enriched core pathway and pathway networks were explored by GeneSpring GX10. Findings: A 239-gene signature was identified according to the year of tumour detection in the training INT–IEO set and correlated with the patients' outcomes. These signatures divided the MILD patients into two distinct survival groups independently of tumour stage, size, histopathological type and screening year. The signatures can also predict survival in the clinically detected cancers (GSE11969). Pathway analyses revealed tumours detected in later years enrichment of the PI3K/PTEN/AKT pathway, with up-regulation of PDPK1, ITGB1 and down-regulation of FOXO1A. Analysis of normal lung tissue from INT–IEO cohort produced signatures distinguishing patients with early from late detected tumours. Interpretation: The distinct pattern of “indolent” and “aggressive” tumour exists in CT-screening detected lung cancer according to the gene expression profiles. The early development of an aggressive phenotype may account for the lack of mortality reduction by screening observed in some cohorts

Webs of crime: Corruption in the perspective of social network analysis

In this thesis, I attempt to apply the network perspective to the study of corruption. First, I deal with current state of theory and research on corruption, which I find to be ignoring relations and interactions among offenders themselves. Then I review literature in the field of covert and criminal networks. The theoretical part of this thesis ends with brief descriptions of two major cases of political corruption in the Czech Republic - so called Nagy case and Rath case. In the methodological part, I introduce basic concepts of social network analysis as well as methods for positional analysis, especially the blockmodelling. In my research, I deal with exploratory analysis of both the aforementioned networks. Using proxy data, I analyse cohesion, centralization, centrality measures and cliques in these networks. Then I use conventional blockmodeling to search for roles and positions within these networks. My results suggest that both networks are dense and centralized with overlapping cliques contrary to other covert networks possibly accounting for their eventual disruption and failure. Positional analysis using varius methods such as CONCOR or different types of cluster analysis reveals a structure resembling the core-periphery model, which is supported by measuring coreness and finding a good..

Five-year antibody persistence in children after one dose of inactivated or live attenuated hepatitis A vaccine

In China, both inactivated hepatitis A (HA) vaccine and live attenuated HA vaccine are available. We conducted a trial to evaluate 5-year immune persistence induced by one dose of inactivated or live attenuated HA vaccines in children. Subjects with no HA vaccination history had randomly received one dose of inactivated or live attenuated HA vaccine at 18–60 months of age. Anti-HAV antibody concentrations were measured before vaccination and at the first, second, and fifth year after vaccination. Suspected cases of hepatitis A were monitored during the study period. A total of 332 subjects were enrolled and 182 provided evaluable serum samples at all planned time points. seropositive rate at 5 y was 85.9% in the inactivated HA vaccine group and 90.7% in the live attenuated HA vaccine group. GMCs were 76.3% mIU/ml (95% CI: 61.7 – 94.4) and 66.8mIU/ml (95% CI: 57.8 – 77.3), respectively. No significant difference in antibody persistence between 2 groups was found. No clinical hepatitis A case was reported. A single dose of an inactivated or live attenuated HA vaccine at 18–60 months of age resulted in high HAV seropositive rate and anti-HAV antibody concentrations that lasted for at least 5 y