Advanced glycation end products enhance reactive oxygen and nitrogen species generation in neutrophils in vitro

Abstract

Increased oxidative stress (OS) in diabetes mellitus is one of the major factors leading to diabetic pathology. However, the mediators and mechanism that provoke OS in diabetes is not fully understood, and it is possible that accumulation of advanced glycation end products (AGEs) formed secondary to hyperglycemic conditions may incite circulating polymorphonuclear neutrophils (PMN) to generate reactive oxygen species (ROS). In this report, we aim to investigate the effect of AGE on reactive oxygen and nitrogen species generation and subsequent OS in PMN. AGE-HSA exert dose- and time-dependent enhancement of ROS and reactive nitrogen intermediates (RNI) generation by PMN. Increased ROS and RNI generation were found to be mediated through the upregulation of NADPH oxidase and inducible nitric oxide synthase (iNOS), respectively, as evident from the fact that AGE-treated neutrophils failed to generate ROS and RNI in presence of diphenyleneiodonium, a flavoprotein inhibitor for both enzymes. Further increased generation of ROS and RNI ceased when the cells were incubated with anti-RAGE antibody suggesting the involvement of AGE-RAGE interaction. Also increased malondialdehyde (MDA) and protein carbonyl formation in AGE-exposed PMN suggest induction of OS by AGE. This study provides evidence that AGEs may play a key role in the induction of oxidative stress through the augmentation of PMN-mediated ROS and RNI generation and this may be in part responsible for development of AGE-induced diabetic pathology.

Oxidative Stress and Mitochondrial Dysfunction across Broad-Ranging Pathologies: Toward Mitochondria-Targeted Clinical Strategies

“…Definitely less investigated than OS, the NS-related endpoints, as 3-nitrotyrosine and NO bioactivity, have been reported to be associated with other redox-related anomalies in some diseases, such as diabetes [127, 128], bladder cancer [191], autism [169], schizophrenia [183], and Sjøgren's syndrome [271]. Albeit relatively unexplored, the subject of nitrosative damage deserves higher attention in further studies, as NS-related endpoints might provide precious insights in the pathogenesis of several OS/MDF-related disorders.…”

A perspective on NETosis in diabetes and cardiometabolic disorders

“…Therefore, constitutive PKC hyperactivity, as also shown in leukocytes exposed to high glucose [38], may predispose neutrophils to NETosis in diabetic patients. NADPH oxidase is also typically overexpressed and -activated in diabetic leukocytes [39], which is probably mediated by advanced glycation endproducts [40,41]. In fact, in resting neutrophils from diabetic subjects or in HL-60 cells exposed to high glucose or the RAGE ligand S100A9, p47phox prematurely translocates to the cell membrane and preassembles with p22phox, a NADPH oxidase membrane subunit [42].…”

Diabetic Peripheral Neuropathy: Should a Chaperone Accompany Our Therapeutic Approach?

“…AGEs are formed when amino groups of proteins react nonenzymatically with reducing sugars (Bansal et al, 2012). Dicarbonyls are AGE precursors that are formed through the oxidation of glucose to glyoxal, the breakdown of Amadori products to 3-deoxyglucosone, and methylglyoxal formation from dihydroxyacetone phosphate (Negre-Salvayre et al, 2009).…”