Comparison of proton channel, phagocyte oxidase, and respiratory burst levels between human eosinophil and neutrophil granulocytes

Abstract

Robust production of reactive oxygen species (ROS) by phagocyte NADPH oxidase (phox) during the respiratory burst (RB) is a characteristic feature of eosinophil and neutrophil granulocytes. In these cells the voltage-gated proton channel (Hv1) is now considered as an ancillary subunit of the phox needed for intense ROS production. Multiple sources reported that the expression of phox subunits and RB is more intensive in eosinophils, than in neutrophils. In most of these studies the eosinophils were not isolated from healthy individuals, and a comparative analysis of Hv1 expression had never been carried out. We performed a systematic comparison of the levels of essential phox subunits, Hv1 expression, and ROS producing capacity between eosinophils and neutrophils of healthy individuals. The expression of phox components was similar, whereas the amount of Hv1 was ∼ 10-fold greater in eosinophils. Furthermore, Hv1 expression correlated with Nox2 expression only in eosinophils. Additionally, in confocal microscopy experiments co-accumulation of Hv1 and Nox2 at the cell periphery was observed in resting eosinophils but not in neutrophils. While phorbol-12-myristate-13-acetate-induced peak extracellular ROS release was ∼ 1.7-fold greater in eosinophils, oxygen consumption studies indicated that the maximal intensity of the RB is only ∼ 1.4fold greater in eosinophils. Our data reinforce that eosinophils, unlike neutrophils, generate ROS predominantly extracellularly. In contrast to previous works we have found that the two granulocyte types display very similar phox subunit expression and RB capacity. The large diff erence in Hv1 expression suggests that its support to intense ROS production is more important at the cell surface.

Effects of Porphyromonas gingivalis LipopolysaccharideTolerized Monocytes on Inflammatory Responses in Neutrophils

“…Respiratory burst in neutrophils is an important host defense strategy utilized to kill invading pathogens. At inflammatory sites, NADPH oxidase complex in activated neutrophils is quickly assembled and ROS, including H 2 O 2 , hypochlorite, hydroxyl radicals and singlet oxygen, are generated to eliminate bacteria, eventually damaging surrounding tissues [ 25 , 26 ]. Both P .…”

Cytokine Regulation of Respiratory Burst in Blood Neutrophils for Prediction of Abdominal Sepsis in Patients With Extended Purulent Peritonitis

“…Индукция син-теза вторичных АФК под воздействием зимозана более выражена у пациентов с РГП, у которых послеоперационный период будет осложнен сепсисом. При этом необходимо отметить, что бактерицидная активность нейтрофилов в боль-шей степени определяется синтезом первичных АФК [4,8,12].…”

“…В то же время активи-рованные нейтрофилы осуществляют не только эффекторные функции, направленные на эли-минацию чужеродного антигена, но и за счет синтеза широкого спектра цитокинов способны стимулировать регуляторные процессы, обеспе-чивающие развитие воспаления и реакции адап-тивного иммунитета [3,14]. Одним из важных аспектов проявления функциональной активности нейтрофилов яв-ляется респираторный взрыв, развивающийся при взаимодействии клеток с объектами фаго-цитоза, интенсивность которого формируется синтезом активных форм кислорода (АФК) [8,12]. Хемилюминесцентный анализ, на основе взаимодействия хемилюминесцентных инди-каторов с активными формами кислорода, по-зволяет охарактеризовать различные параметры респираторного взрыва и тем самым оценить уровень реактивности нейтрофильных грануло-цитов [4,7].…”

The intimate and controversial relationship between voltage‐gated proton channels and the phagocyte NADPH oxidase

“…H + currents are smaller in human neutrophils than human eosinophils, and tiny in human myotubes. Human eosinophils have 10‐fold more H V 1 protein than human neutrophils . The seductive argument that proton currents are larger in eosinophils than in neutrophils because of their greater ROS production does not account for basophils, which have large H + currents but no respiratory burst.…”