scholarly journals Accumulation of Cytochrome b558 at the Plasma Membrane: Hallmark of Oxidative Stress in Phagocytic Cells

2022 ◽  
Vol 23 (2) ◽  
pp. 767
Author(s):  
Stephenson B. Owusu ◽  
Sophie Dupré-Crochet ◽  
Tania Bizouarn ◽  
Chantal Houée-Levin ◽  
Laura Baciou

Neutrophils play a very key role in the human immune defense against pathogenic infections. The predominant players in this role during the activation of neutrophils are the release of cytotoxic agents stored in the granules and secretory vesicles and the massive production of reactive oxygen species (ROS) initiated by the enzyme NADPH oxidase. In addition, in living organisms, cells are continuously exposed to endogenous (inflammations, elevated neutrophil presence in the vicinity) and exogenous ROS at low and moderate levels (travels by plane, radiotherapy, space irradiation, blood banking, etc.). To study these effects, we used ROS induced by gamma radiation from low (0.2 Gy) to high (25 Gy) dose levels on PLB-985 cells from a myeloid cell line differentiated to neutrophil-like cells that are considered a good alternative to neutrophils. We determined a much longer lifetime of PLB-985 cells than that of neutrophils, which, as expected, decreased by increasing the irradiation dose. In the absence of any secondary stimulus, a very low production of ROS is detected with no significant difference between irradiated and non-irradiated cells. However, in phagocytosing cells, irradiation doses above 2 Gy enhanced oxidative burst in PLB-985 cells. Whatever the irradiation dose, NADPH oxidase devoid of its cytosolic regulatory units is observed at the plasma membrane in irradiated PLB-985 cells. This result is different from that observed for irradiated neutrophils in which irradiation also induced a translocation of regulatory subunits suggesting that the signal transduction mechanism or pathway operate differently in both cells.

Antioxidants ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 890
Author(s):  
Annelise Vermot ◽  
Isabelle Petit-Härtlein ◽  
Susan M. E. Smith ◽  
Franck Fieschi

The reactive oxygen species (ROS)-producing enzyme NADPH oxidase (NOX) was first identified in the membrane of phagocytic cells. For many years, its only known role was in immune defense, where its ROS production leads to the destruction of pathogens by the immune cells. NOX from phagocytes catalyzes, via one-electron trans-membrane transfer to molecular oxygen, the production of the superoxide anion. Over the years, six human homologs of the catalytic subunit of the phagocyte NADPH oxidase were found: NOX1, NOX3, NOX4, NOX5, DUOX1, and DUOX2. Together with the NOX2/gp91phox component present in the phagocyte NADPH oxidase assembly itself, the homologs are now referred to as the NOX family of NADPH oxidases. NOX are complex multidomain proteins with varying requirements for assembly with combinations of other proteins for activity. The recent structural insights acquired on both prokaryotic and eukaryotic NOX open new perspectives for the understanding of the molecular mechanisms inherent to NOX regulation and ROS production (superoxide or hydrogen peroxide). This new structural information will certainly inform new investigations of human disease. As specialized ROS producers, NOX enzymes participate in numerous crucial physiological processes, including host defense, the post-translational processing of proteins, cellular signaling, regulation of gene expression, and cell differentiation. These diversities of physiological context will be discussed in this review. We also discuss NOX misregulation, which can contribute to a wide range of severe pathologies, such as atherosclerosis, hypertension, diabetic nephropathy, lung fibrosis, cancer, or neurodegenerative diseases, giving this family of membrane proteins a strong therapeutic interest.


2021 ◽  
pp. 175319342110215
Author(s):  
Birkan Kibar ◽  
Ali Cavit ◽  
Abdullah Örs

We carried out a prospective randomized study to compare the clinical and radiological results of metacarpal diaphyseal fractures treated with retrograde intramedullary headless cannulated screws (IHCS) and plates. Fractures were fixed with IHCS in 34 patients (37 metacarpals) and locked miniplates in 35 patients (40 metacarpals). The mean age was 33 years (range 18–61) in the IHCS group and 32 years (range 17–68) in plate group. All patients were followed up for 1 year. All fractures in the IHCS group united but there was one nonunion in the plate group. At final follow-up, there was no significant difference between the groups in total active movement, visual analogue pain score, Disabilities of the Arm, Shoulder, and Hand score and grip strength, although the study was not sufficiently powered to exclude differences with certainty. IHCS is a safe and fast technique that is a good alternative to plate fixation in metacarpal diaphyseal fractures. Level of evidence: I


1989 ◽  
Vol 121 (6) ◽  
pp. 817-820 ◽  
Author(s):  
B. Wolach ◽  
B. Lebanon ◽  
A. Jedeikin ◽  
M. S. Shapiro ◽  
L. Shenkman

Abstract. We have examined neutrophil adherence, chemotactic activity, and random migration in 35 hyperthyroid patients with Graves' disease and 106 normal volunteers. No statistically significant differences were found between granulocyte adherence of 17 hyperthyroid subjects (67 ± 15.6%) and 81 healthy volunteers (63.1 ± 17%). In 3 thyrotoxic patients, impaired neutrophil adherence was found, which resolved when thyroid function returned to normal. The neutrophil chemotactic activity of 32 normal controls was 107.5 ± 21.4 cells, and the random migration 36 ± 15.5 cells. No statistically significant difference was demonstrated in 13 hyperthyroid patients who had a neutrophil chemotactic activity of 102 ± 14.6 cells and a random migration of 31.2 ± 13.2 cells. Defective chemotactic activity and random migration was found in 2 patients. Neutrophil functions returned to normal in one of the two subjects who were re-evaluated when thyroid function recovered. In summary, 14% of hyperthyroid patients had impaired leukocyte functions. However, severe pyogenic infections are quite rare in hyperthyroid patients, indicating that the observed alterations in function of phagocytic cells are not clinically important.


Planta ◽  
2014 ◽  
Vol 240 (5) ◽  
pp. 1023-1035 ◽  
Author(s):  
Jiangli Zhang ◽  
Changsheng Chen ◽  
Di Zhang ◽  
Houhua Li ◽  
Pengmin Li ◽  
...  

2008 ◽  
Vol 294 (3) ◽  
pp. G717-G727 ◽  
Author(s):  
Robert C. De Lisle ◽  
Weihong Xu ◽  
Bruce A. Roe ◽  
Donna Ziemer

The Dmbt1 gene encodes alternatively spliced glycoproteins that are either membrane-associated or secreted epithelial products. Functions proposed for Dmbt1 include it being a tumor suppressor, having roles in innate immune defense and inflammation, and being a Golgi-sorting receptor in the exocrine pancreas. The heavily sulfated membrane glycoprotein mucin-like glycoprotein (Muclin) is a Dmbt1 product that is strongly expressed in organs of the gastrointestinal (GI) system. To explore Muclin's functions in the GI system, the Dmbt1 gene was targeted to produce Muclin-deficient mice. Muclin-deficient mice have normal body weight gain and are fertile. The Muclin-deficient mice did not develop GI tumors, even when crossed with mice lacking the known tumor suppressor p53. When colitis was induced by dextran sulfate sodium, there was no significant difference in disease severity in Muclin-deficient mice. Also, when acute pancreatitis was induced with supraphysiological caerulein, there was no difference in disease severity in the Muclin-deficient mice. Exocrine pancreatic function was impaired, as measured by attenuated neurohormonal-stimulated amylase release from Muclin-deficient acinar cells. Also, by [35S]Met/Cys pulse-chase analysis, traffic of newly synthesized protein to the stimulus-releasable pool was significantly retarded in Muclin-deficient cells compared with wild type. Thus Muclin deficiency impairs trafficking of regulated proteins to a stimulus-releasable pool in the exocrine pancreas.


PEDIATRICS ◽  
1991 ◽  
Vol 88 (1) ◽  
pp. 183-185
Author(s):  
SHIGENOBU UMEKI

To the Editor.— Such phagocytic cells as neutrophils and macrophages are crucial elements in the host defense against bacterial [See table in the PDF file] and fungal infections. Microbicidal activity depends to a large extent on NADPH oxidase system, which can be activated by stimuli (bacteria, fungi) and which generates the superoxide anion and other highly reactive forms of reduced oxygen.1,2 The neutrophil NADPH oxidase system is composed functionally of membrane-bound catalytic components (which consist of at least two constituents, the low potential cytochrome b5583-5 and flavoprotein5) and soluble cytosolic components6,7 which participate as either catalytic or regulatory elements.


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