A new chemiluminescence paradox: selective inhibition of isoluminol-amplified activity in phagocytes by peptides from annexin AI

The effect and possible clinical efficacy of in vivo inhibition of neutrophil extracellular traps by blockade of PI3K-gamma on the pathogenesis of microscopic polyangiitis

OBJECTIVE

Neutrophil extracellular traps (NETs) are peculiar structures composed of the externalized chromatin with intracellular proteins and formed by activated neutrophils in a reactive oxygen species (ROS)-dependent manner. Aberrant NETs are considered to be autoantigens for anti-neutrophil cytoplasmic antibodies (ANCAs) underling the development of microscopic polyangiitis (MPA). However, little is known regarding the therapeutic efficacy of in vivo inhibition of NET formation (NETosis) on MPA pathogenesis. This study determines whether reducing NETosis prevents ANCA production and improves characteristic involvement.

METHODS

A mouse model of MPA induced by administering a novel extract from Candida albicans was devised. By applying this method to mice lacking phosphoinositide 3-kinase gamma (PI3K-gamma), which is indispensable for ROS production in neutrophils, we investigated the levels of in vivo NETs, ANCA titers and histological damage.

RESULTS

Our model exhibited accumulation of NETs in vivo, elevation of ANCA titers and characteristic pathologies mimicking human MPA, including small-vessel vasculitis and crescentic glomerulonephritis. Strikingly, these abnormalities were reduced by genetically and/or pharmacologically blocking PI3K-gamma. Moreover, a pharmacological PI3K-gamma blockade decreased the levels of human NETs.

CONCLUSION

Our results suggest that in vivo inhibition of NETosis by blocking PI3K-gamma could be a promising therapeutic strategy for the pathogenesis of MPA.

Roles of reactive oxygen species in female reproduction

Reactive oxygen species (ROS) are highly reactive oxidizing agents. Cells, under aerobic conditions, have a defence system against ROS, and in normal circumstances, there is an appropriate balance between pro-oxidants and antioxidants. When an overproduction of ROS develops or the body fails to eliminate ROS in excess, oxidative stress arises, during which ROS accumulate and damage cells and tissues. Besides their noxious effects, accumulating data have shown that controlled and adequate ROS concentrations exert physiologic functions. Different studies have confirmed the presence of ROS and the transcripts of the various antioxidant enzymes in the female reproductive tract. When ROS production overwhelms antioxidant defences, oxidative stress occurs, which may deeply threaten the anatomical and functional integrity of the genital tract. This review addresses the main physiological and pathological roles exerted by ROS and their scavenging systems in several processes involved in the main physiological functions of the female reproductive tract of both women and domestic animals. Particularly, the involvement of the oxidant system in several reproductive processes is investigated, such as follicular development, ovarian steroidogenesis, ovulation, corpus luteum formation and function, luteolysis, germ cell function, maintenance of pregnancy and beginning of parturition.

In vivo monitor oxidative burst induced by Cd2+ stress for the oilseed rape (Brassica napus L.) based on electrochemical microbiosensor

INTRODUCTION

Since the mechanism of Cd(2+) stress for plants is not clear, an in vivo method to monitor Cd(2+) stress for plants is necessary. However, oxidative burst (OB) is a signal messenger in the process of Cd(2+) stress for plants.

OBJECTIVE

To establish an electrochemical method with poly-o-phenylenediamine and Pt microparticle modified Pt electrode (POPD-Pt-MP-Pt) as a microbiosensor for the in vivo detection of oxidative burst induced by Cd(2+) stress in oilseed rape (Brassica napus L.).

METHODOLOGY

The optimal fabrication of POPD-Pt-MP-Pt biosensor was achieved. Electrochemical signal was collected by amperometry.

RESULTS

After oilseed rape was exposed to 84.9 mM CdCl(2) stress, three oxidative bursts were observed in oilseed rape by amperometry at 3.3 h, 8.4 h and 13.2 h, respectively. However, there was no obvious signal observed in the controlled assay.

CONCLUSION

This contribution presents the in vivo monitoring of the OB process induced by Cd(2+) stress in oilseed rape by POPD-Pt-MP-Pt microbiosensor in real-time. The novel electrochemical microbiosensor not only facilitates the real-time study in plant self-defence response to the adverse environment such as Cd(2+) stress, but also provides an effective tool for probing the self-defence mechanism in plants.