Antiviral activity of hypothiocyanite produced by lactoperoxidase against influenza A and B viruses and mode of its antiviral action

Hypothiocyanite (OSCN-) is a natural component of human saliva and is produced by the lactoperoxidase (LPO)/thiocyanate/hydrogen peroxide (H2O2) system. OSCN- has been previously shown to exhibit antiviral activity against influenza viruses (IFV) A/H1N1/2009 and A/H1N2/2009 in vitro as well as antimicrobial and antifungal activities. We elucidated the antiviral activity of OSCN- against both IFV types A and B and the mode of its antiviral action. OSCN- was produced constantly at 900 ± 200 μmol/l in Na3PO4 buffer solution containing NaSCN and LPO in the presence of H2O2 as an original OSCN- solution. In a plaque reduction assay, IFV A/PR/8/34 (H1N1), A/Fukushima/13/43 (H3N2), B/Singapore/222/97, and B/Fukushima/15/93 were exposed to various concentrations of OSCN- for 0 to 30 min before adsorption to MDCK cells, and plaque formation was examined. OSCN- exhibited significant similar antiviral activities against all four viruses without cytotoxicity, and the EC50 values for them were from 57 ± 16 to 148 ± 27 μmol/l regardless of the exposure times. The exposure of MDCK cells to OSCN- before viral adsorption did not affect its anti-IFV activity (EC50: more than 450 μmol/l), but the exposure after viral adsorption affected it moderately (EC50: 380 ± 40 μmol/l). Moreover, the exposure of virus particles to OSCN- at 450 μmol/l did not affect the hemagglutinin activity of IFV in hemagglutination inhibition assay. These results suggest that the attachment of OSCN- to the viral envelope critically contributes to the mode of antiviral action of OSCN- without interfering with viral adsorption. Keywords: hypothiocyanite; influenza virus type A; influenza virus type B; lactoperoxidase; antiviral activity.

Interleukin-17A negatively regulates lymphangiogenesis in T helper 17 cell-mediated inflammation

During inflammation lymphatic vessels (LVs) are enlarged and their density is increased to facilitate the migration of activated immune cells and antigens. However, after antigen clearance, the expanded LVs shrink to maintain homeostasis. Here we show that interleukin (IL)-17A, secreted from T helper type 17 (T_H17) cells, is a negative regulator of lymphangiogenesis during the resolution phase of T_H17-mediated immune responses. Moreover, IL-17A suppresses the expression of major lymphatic markers in lymphatic endothelial cells and decreases in vitro LV formation. To investigate the role of IL-17A in vivo, we utilized a cholera toxin-mediated inflammation model and identified inflammation and resolution phases based on the numbers of recruited immune cells. IL-17A, markedly produced by T_H17 cells even after the peak of inflammation, was found to participate in the negative regulation of LV formation. Moreover, blockade of IL-17A resulted in not only increased density of LVs in tissues but also their enhanced function. Taken together, these findings improve the current understanding of the relationship between LVs and inflammatory cytokines in pathologic conditions.

Environmental and health effects of the herbicide glyphosate

The herbicide glyphosate, N-(phosphonomethyl) glycine, has been used extensively in the past 40years, under the assumption that side effects were minimal. However, in recent years, concerns have increased worldwide about the potential wide ranging direct and indirect health effects of the large scale use of glyphosate. In 2015, the World Health Organization reclassified glyphosate as probably carcinogenic to humans. A detailed overview is given of the scientific literature on the movement and residues of glyphosate and its breakdown product aminomethyl phosphonic acid (AMPA) in soil and water, their toxicity to macro- and microorganisms, their effects on microbial compositions and potential indirect effects on plant, animal and human health. Although the acute toxic effects of glyphosate and AMPA on mammals are low, there are animal data raising the possibility of health effects associated with chronic, ultra-low doses related to accumulation of these compounds in the environment. Intensive glyphosate use has led to the selection of glyphosate-resistant weeds and microorganisms. Shifts in microbial compositions due to selective pressure by glyphosate may have contributed to the proliferation of plant and animal pathogens. Research on a link between glyphosate and antibiotic resistance is still scarce but we hypothesize that the selection pressure for glyphosate-resistance in bacteria could lead to shifts in microbiome composition and increases in antibiotic resistance to clinically important antimicrobial agents. We recommend interdisciplinary research on the associations between low level chronic glyphosate exposure, distortions in microbial communities, expansion of antibiotic resistance and the emergence of animal, human and plant diseases. Independent research is needed to revisit the tolerance thresholds for glyphosate residues in water, food and animal feed taking all possible health risks into account.

A multi-throughput multi-organ-on-a-chip system on a plate formatted pneumatic pressure-driven medium circulation platform

This paper reports a multi-throughput multi-organ-on-a-chip system formed on a pneumatic pressure-driven medium circulation platform with a microplate-sized format as a novel type of microphysiological system. The pneumatic pressure-driven platform enabled parallelized multi-organ experiments (i.e. simultaneous operation of multiple multi-organ culture units) and pipette-friendly liquid handling for various conventional cell culture experiments, including cell seeding, medium change, live/dead staining, cell growth analysis, gene expression analysis of collected cells, and liquid chromatography-mass spectrometry analysis of chemical compounds in the culture medium. An eight-throughput two-organ system and a four-throughput four-organ system were constructed on a common platform, with different microfluidic plates. The two-organ system, composed of liver and cancer models, was used to demonstrate the effect of an anticancer prodrug, capecitabine (CAP), whose metabolite 5-fluorouracil (5-FU) after metabolism by HepaRG hepatic cells inhibited the proliferation of HCT-116 cancer cells. The four-organ system, composed of intestine, liver, cancer, and connective tissue models, was used to demonstrate evaluation of the effects of 5-FU and two prodrugs of 5-FU (CAP and tegafur) on multiple organ models, including cancer and connective tissue.

The importance of dermoscopy for the diagnosis of acquired bilateral telangiectatic macules: the angioid streak pattern reveals underlying chronic liver disease

BACKGROUND

Acquired bilateral telangiectatic macules (ABTM) are a newly recognized disease entity, which manifest as multiple telangiectatic pigmented macules confined mostly to the upper arms.

OBJECTIVES

To evaluate clinical and dermoscopic features in a group of 50 patients with ABTM and to determine the diagnostic usefulness of dermoscopy in ABTM.

METHODS

Patients were selected from two tertiary teaching hospitals in Korea [Pusan National University Hospitals (Busan and Yangsan)]. Fifty patients (41 males and 9 females; mean age 48.1 years; range 26-78 years) with ABTM were included in the study. The dermoscopic findings were graded using a 4-point scale: none (0), mild (1), moderate (2) and severe (3). In addition, the results of 23 patients with and 27 patients without chronic liver disease (CLD) were compared to determine whether the presence of CLD affects dermoscopic findings.

RESULTS

Three distinct dermoscopic patterns were observed; brown pigmentations, telangiectasia (linear-irregular vessels) and an angioid streak pattern. Brown pigmentation in the group without CLD had higher severity score than those in CLD group (mean score: 2.00 vs. 1.48, P = 0.033). However, mean telangiectasia severity score was higher in the CLD group (2.14 vs. 1.39, P < 0.001). The angioid streak pattern was more severe and more common in patients with CLD than in those without [1.37 vs. 0.35 (P < 0.001) and 63.0% vs. 26.1%, respectively].

CONCLUSIONS

Detailed observations with dermoscopy can provide first clues of the presence of ABTM and underlying chronic liver disease.

Enhanced Th2 cell differentiation and function in the absence of Nox2

BACKGROUND

Patients with chronic granulomatous disease (CGD), whom inherit abnormal function of NADPH oxidase 2 (Nox2), suffer from hyperinflammatory responses in lung as well as bacterial and fungal infection. There have been studies to reveal the function of Nox2 in hyperinflammatory diseases, especially in asthma, but the exact role of Nox2 in asthma is still unclear and controversial. Therefore, we attempted to clarify the exact role of Nox2 in asthma, using various experimental asthma models.

METHODS

Asthma phenotypes were analyzed in response to various allergen-induced experimental asthma using Nox2-deficient mice and recombinase gene-activating-1-deficient mice. To understand the underlying mechanisms of exaggerated Th2 effector functions, we investigated the degree of T-cell activation, levels of activation-induced cell death (AICD), and regulatory T (Treg)-cell differentiation in Nox2-deficient T cells.

RESULTS

Asthma phenotypes were increased through enhanced Th2 differentiation and function in Nox2-null mice regardless of dose and route of various allergens. Nox2-deficient T cells also showed hyperactivation, reduced AICD, and diminished Treg-cell differentiation through increased AKT phosphorylation (T308/S473) and enhanced mitochondrial ROS production.

CONCLUSION

Our findings indicate that Nox2 deficiency results in exaggerated experimental asthma, which is caused by enhanced Th2 effector function in a T-cell-intrinsic manner.