Activated protein C protects against myocardial ischemic/reperfusion injury through AMP-activated protein kinase signaling

BACKGROUND

Activated protein C (APC) is a vitamin K-dependent plasma serine protease that down-regulates clotting and inflammatory pathways. It is known that APC exerts a cardioprotective effect by decreasing apoptosis of cardiomyocytes and inhibiting expression of inflammatory mediators after myocardial ischemia.

OBJECTIVES

The objective of this study was to understand the mechanism of the APC-mediated cardioprotection against ischemic injury.

METHODS

Cardioprotective activities of wild-type APC and two derivatives, having either dramatically reduced anticoagulant activity or lacking signaling activity, were monitored in an acute ischemia/reperfusion injury model in which the left anterior descending coronary artery (LAD) was occluded.

RESULTS

APC reduced the myocardial infarct size by a mechanism that was largely independent of its anticoagulant activity. Thus, the non-anticoagulant APC-2Cys mutant, but not the non-signaling APC-E170A mutant, attenuated myocardial infarct size by EPCR and PAR-1-dependent mechanisms. Further studies revealed that APC acts directly on cardiomyocytes to stimulate the AMP-activated protein kinase (AMPK) signaling pathway. The activation of AMPK by APC ameliorated the post-ischemic cardiac dysfunction in isolated perfused mouse hearts. Moreover, both APC and APC-2Cys inhibited production of TNFα and IL-6 in vivo by attenuating the ischemia/reperfusion-induced JNK and NF-κB signaling pathways.

CONCLUSIONS

APC exerts a cardioprotective function in ischemic/reperfusion injury through modulation of AMPK, NF-κB and JNK signaling pathways.

Pharmacokinetics of antofloxacin hydrochloride in healthy male subjects after multiple intravenous dose administration

The purpose of the study was to evaluate pharmacokinetic characteristics of antofloxacin hydrochloride, a new fluoroquinolone antibiotic, during a multiple, intravenous dosing regimen. Twelve healthy, Chinese male volunteer subjects were each given 300 mg of antofloxacin by intravenous infusion once daily for 7 days. Blood and urine samples were taken at designated time points for analysis of antofloxacin concentration by high-performance liquid chromatography (HPLC). Safety and tolerability were assessed by evaluation of subject complaints, vital signs, electrocardiograms, electroencephalograms, clinical chemistry parameters, haematology and urinalysis and prothrombin time. The serum steady concentration of antofloxacin was obtained in 96 h after the administration of a daily intravenous dose of 300 mg of the drug. In the present study, the following pharmacokinetic parameters after 7 days of treatment with antofloxacin were determined to be: C(max) 3.81 ± 0.66 mg/L, C(min) 0.85 ± 0.19 mg/L, AUC(0-24) 60.51 ± 8.30 mg/L·h, C(av) 2.52 ± 0.35 mg/L, PTF 87.45 ± 3.37%, t(1/2)β 20.34 ± 1.88 h. The C(max) and AUC(0-24) after 7-day treatment were both higher than after the first dose (by 43% and 110%, respectively). The cumulative urinary elimination of antofloxacin within 96 h after the last dose was about 56%. During the study, there were neither subject complaints nor significant adverse clinical findings. Antofloxacin, administered intravenously as a single, daily 300 mg dose for 7 days, demonstrated favourable pharmacokinetic characteristics and tolerability. The results of this study indicate that antofloxacin hydrochloride is suitable for further clinical study.

Impact of luteolin on the production of alpha-toxin by Staphylococcus aureus

AIMS

To investigate the influence of subinhibitory concentrations of luteolin on the production of α-toxin in Staphylococcus aureus.

METHODS AND RESULTS

The minimal inhibitory concentrations (MICs) were determined using a broth microdilution method, and the MICs of luteolin against the tested Staph. aureus strains ranged from 16 to 64 μg ml(-1). Haemolysis, Western blot and real-time reverse transcription (RT)-PCR assays were used to evaluate the effect of luteolin on Staph. aureusα-toxin secretion and on the level of gene expression, respectively. The data indicated that subinhibitory concentrations of luteolin dose dependently decreased the production of α-toxin in both meticillin-sensitive Staph. aureus (MSSA) and meticillin-resistant Staph. aureus (MRSA). Furthermore, the transcriptional levels of agr (accessory gene regulator) in Staph. aureus were also inhibited by luteolin.

CONCLUSIONS

Luteolin decreases the production and/or secretion of α-toxin in Staph. aureus; the reduced production may be dependent, in part, upon the luteolin-induced inhibition of the agr locus.

SIGNIFICANCE AND IMPACT OF THE STUDY

The findings indicate that luteolin may be used as a basis for the development of antimicrobial agents aimed at bacterial virulence factors.

Hepatitis B virus X protein downregulates expression of the miR-16 family in malignant hepatocytes in vitro

BACKGROUND

Hepatitis B virus X protein (HBx) is involved in the initiation and progression of hepatocellular carcinoma (HCC) by regulating the host protein-coding genes. In this study, we showed that HBx altered the expression of microRNAs (miRNAs) to promote proliferation and transformation in malignant hepatocytes in vitro.

METHODS

miRNA microarray and quantitative reverse-transcription polymerase chain reactions (qRT-PCRs) were performed to identify miRNAs that were differentially regulated by HBx in HCC cells. Protein, mRNA, and miRNA expression analyses; cell cycle and apoptosis analyses; loss/gain-of-function analysis; and luciferase reporter assays were performed to delineate the consequences of miR-16 family repression in HepG2 cells.

RESULTS

Hepatitis B virus X protein induced widespread deregulation of miRNAs in HepG2 cells, and the downregulation of the miR-16 family was reproducible in HepG2, SK-HEP-1, and Huh7 cells. CCND1, a target of the miR-16 family, was derepressed by HBx in HepG2 cells. c-Myc mediated the HBx-induced repression of miR-15a/16 in HepG2 cells. Ectopically expressed miR-15a/16 suppressed the proliferation, clonogenicity, and anchorage-independent growth of HBx-expressing HepG2 cells by arresting them in the G1 phase and inducing apoptosis, whereas reduced expression of miR-16 accelerated the growth and cell-cycle progression of HepG2 cells.

CONCLUSIONS

Hepatitis B virus X protein altered the in vitro expression of miRNAs in host malignant hepatocytes, particularly downregulating the miR-16 family. Repression of miR-15a/16 is c-Myc mediated and is required for the HBx-induced transformation of HepG2 cells in vitro. Therefore, miR-16 family may serve as a therapeutic target for hepatitis B virus (HBV)-associated HCC.

Measurement of the B0 production cross section in pp collisions at sqrt[s] = 7 TeV

Measurements of the differential production cross sections dσ/dpTB and dσ/dyB for B0 mesons produced in pp collisions at sqrt[s] = 7 TeV are presented. The data set used was collected by the CMS experiment at the LHC and corresponds to an integrated luminosity of 40 pb-1. The production cross section is measured from B0 meson decays reconstructed in the exclusive final state J/ψKS0, with the subsequent decays J/ψ → μ + μ - and KS0 → π+}π-. The total cross section for pTB>5 GeV and |yB|<2.2 is measured to be 33.2 ± 2.5 ± 3.5 μb, where the first uncertainty is statistical and the second is systematic.

Efficient cochlear gene transfection in guinea-pigs with adeno-associated viral vectors by partial digestion of round window membrane

The auditory portion of the inner ear, the cochlea, is an ideal organ for local gene transfection owing to its relative isolation. Various carriers have been tested for cochlear gene transfection. To date, viral vectors appear to have much higher transfection efficacy than non-viral mechanisms. Among these vectors, recombinant adeno-associated virus (rAAV) vectors have several advantages such as being non-pathogenic and the ability to produce prolonged gene expression in various cell types. However, rAAV vectors cannot pass through the intact round window membrane (RWM), otherwise a very attractive approach to access the human inner ear. In this study, performed in guinea-pigs, we describe a method to increase the permeability of RWM to rAAV vectors by partial digestion with collagenase solution. Elevated delivery of rAAV across the partially digested RWM increased transfection efficacy to a satisfactory level, even though it was still lower than that achieved by direct cochleostomy injection. Functional tests (auditory brainstem responses) showed that this enzymatic manipulation did not cause permanent hearing loss if applied appropriately. Morphological observations suggested that the damage to RWM caused by partial digestion healed within four weeks. Taken together, these findings suggest that partial digestion of the RWM is a safe and effective method for increasing the transfection of cochlear sensory cells with rAAV.

PLA2G6 gene mutation in autosomal recessive early-onset parkinsonism in a Chinese cohort

OBJECTIVE

Mutations in the PLA2G6 gene at the PARK14 locus have been reported in complicated parkinsonism. To assess the prevalence of and phenotypes associated with PLA2G6 gene mutations, we screened PLA2G6 mutations in a cohort of patients with autosomal recessive early-onset parkinsonism (AREP).

METHODS

We selected 12 families with AREP in which the Parkin, PINK1, DJ-1, ATP13A2, and FBXO7 gene mutations had been previously excluded. All patients came from the mainland of China. The entire PLA2G6 coding region and exon-intron boundaries were sequenced from genomic DNA templates. We then performed PET studies on individuals in the pedigree with a homozygous PLA2G6 mutation, and investigated the enzyme activity level of the mutation.

RESULTS

A homozygous missense mutation, c.G991T (p.D331Y), was identified in an autosomal recessive case. A younger sister of the p.D331Y-carrying patient was also homozygous for the mutation, but with no extrapyramidal symptoms. A PET study showed a substantial reduction in dopamine transporter (DAT) binding in the p.D331Y patient, and a slight reduction in DAT binding in his sister. In vitro, we experimentally demonstrate that the D331Y mutation caused an approximately 70%reduction in enzyme activity.

CONCLUSIONS

We have confirmed that the PLA2G6 gene allocated PARK14 locus and is associated with AREP.

Search for neutral minimal supersymmetric standard model Higgs bosons decaying to tau pairs in pp collisions at √s=7 TeV

A search for neutral minimal supersymmetric standard model (MSSM) Higgs bosons in pp collisions at the LHC at a center-of-mass energy of 7 TeV is presented. The results are based on a data sample corresponding to an integrated luminosity of 36  pb(-1) recorded by the CMS experiment. The search uses decays of the Higgs bosons to tau pairs. No excess is observed in the tau-pair invariant-mass spectrum. The resulting upper limits on the Higgs boson production cross section times branching fraction to tau pairs, as a function of the pseudoscalar Higgs boson mass, yield stringent new bounds in the MSSM parameter space.

Skewing the Balance of Regulatory T-Cells and T-Helper 17 Cells in Breast Cancer Patients

This study investigated the distribution of interleukin (IL)-17-producing CD4+ T-cells (T-helper [Th17] cells) in relation to CD4+CD25+CD127− cells (regulatory T-cells [Treg]) in tumour-infiltrating lymphocytes (TILs) and peripheral blood mononuclear cells (PBMCs) from breast cancer patients. The Th17 and Treg cells were evaluated by flow cytometry and reported as a percentage of total CD4+ cells. In TILs from early breast cancer patients ( n = 12), the frequency of Th17 cells was significantly higher than in PBMCs (14.5 ± 7.2% versus 6.9 ± 2.1%). In TILs from patients with advanced breast cancer ( n = 15), the frequency of Th17 cells was also significantly higher than that in PBMCs (9.1 ± 5.7% versus 3.2 ± 2.3%) but lower compared with early disease. The Th17/Treg ratio in TILs was markedly increased in early versus advanced disease. In conclusion, Th17 and Treg cell accumulation in the tumour microenvironment of breast cancer occurred in early disease; Th17 cell infiltration gradually decreased and Treg cells accumulated with disease progression.