Haemoglobin-induced oxidative stress is associated with both endogenous peroxidase activity and H₂O₂generation from polyunsaturated fatty acids

Abstract

Patients with increased haemolytic haemoglobin (Hb) have 10-20-times greater incidence of cardiovascular mortality. The objective of this study was to evaluate the role of Hb peroxidase activity in LDL oxidation. The role of Hb in lipid peroxidation, H(2)O(2) generation and intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) was assessed using NaN(3), a peroxidase inhibitor, catalase, a H(2)O(2) decomposing enzyme and human umbilical vein endothelial cells (HUVECs), respectively. Hb induced H(2)O(2) production by reacting with LDL, linoleate and cell membrane lipid extracts. Hb-induced LDL oxidation was inhibited by NaN(3) and catalase. Furthermore, Hb stimulated ICAM-1 and VCAM-1 expression, which was inhibited by the antioxidant, probucol. Thus, the present study suggests that the peroxidase activity of Hb produces atherogenic, oxidized LDL and oxidized polyunsaturated fatty acids (PUFAs) in the cell membrane and reactive oxygen species (ROS) formation mediated Hb-induced ICAM-1 and VCAM-1 expression.

Cell-free identification of novel N-myristoylated proteins from complementary DNA resources using bioorthogonal myristic acid analogues

“…4B (panels c and d). Because it is known that the rabbit reticulocyte lysate contains a certain amount of hemoglobin and that hemoglobin has peroxidase activity [26], it is speculated that the non-specific background observed in the low-molecular weight region is due to the presence of hemoglobin in the lysate. In fact, similar protein bands in the low-molecular weight region were detected by ECL in the rabbit reticulocyte lysate and purified bovine hemoglobin without antibody/protein G-HRP or streptavidin-HRP treatment (see Supplementary Fig.…”

Thinking outside the cell: how cell-free hemoglobin can potentiate acute lung injury

“…Interestingly, antioxidants and iron chelators were not effective in blocking the effects of methemoglobin, suggesting that reactive oxygen species (ROS) and iron are not required for methemoglobin effects. These findings are in distinct contrast to studies of the effects of free hemoglobin on other cell types, which implicate either ROS generation (5,11) or nitric oxide scavenging (6,17) as the mechanism of cellular effects. However, the possibility of insufficient duration of exposure to antioxidants and iron chelators prior to treatment with hemoglobin should be noted.…”

A New Method to Visualize the Intact Subretina From Retinal Pigment Epithelium to Retinal Tissue in Whole Mount of Pigmented Mouse Eyes

“…Thus, H 2 O 2 treatment for melanin bleaching seems to affect and/or destroy some cell surface epitopes, as already reported in a blocking procedure of endogenous peroxidase activity. 8 However, it would be worthy to note that GFP immunoreactivity is maintained after H 2 O 2 melanin bleaching treatment although endogenous GFP signals disappear. Therefore, careful optimization may be required for immunostaining depending on the tissues and antibodies used.…”