The Different Responsiveness of C3- and C5-deficient Murine BM Cells to Oxidative Stress Explains Why C3 Deficiency, in Contrast to C5 Deficiency, Correlates with Better Pharmacological Mobilization and Engraftment of Hematopoietic Cells.

The liver-derived circulating in peripheral blood and intrinsic cell-expressed complement known as complosome orchestrate the trafficking of hematopoietic stem/progenitor cells (HSPCs) both during pharmacological mobilization and homing/engraftment after transplantation. Our previous research demonstrated that C3 deficient mice are easy mobilizers, and their HSPCs engraft properly in normal mice. In contrast, C5 deficiency correlates with poor mobilization and defects in HSPCs' homing and engraftment.

Defect in Migration of HSPCs in Nox-2 Deficient Mice Explained by Impaired Activation of Nlrp3 Inflammasome and Impaired Formation of Membrane Lipid Rafts.

NADPH oxidase 2 (Nox2), a superoxide-generating enzyme, is a source of reactive oxygen species (ROS) that regulate the intracellular redox state, self-renewal, and fate of hematopoietic stem/progenitor cells (HSPCs). Nox2 complex expressed on HSPCs associated with several activated cell membrane receptors increases the intracellular level of ROS. In addition, ROS are also released from mitochondria and, all together, are potent activators of intracellular pattern recognition receptor Nlrp3 inflammasome, which regulates the trafficking, proliferation, and metabolism of HSPCs.

Mutual Activation of Two Radical Trapping Agents: Unusual "Win-Win Synergy" of Resveratrol and TEMPO during Scavenging of dpph Radical in Methanol.

The reaction of the 2,2'-diphenyl-1-picrylhydrazyl radical (dpph) with resveratrol in methanol ( = 192 M s) is greatly accelerated in the presence of stable nitroxyl radical TEMPO ( = 1.4 × 10 M s). This synergistic effect is surprising because TEMPO alone reacts with dpph relatively slowly ( = 31 M s in methanol and 0.

Concentration-dependent HAT/ET mechanism of the reaction of phenols with 2,2-diphenyl-1-picrylhydrazyl (dpph˙) in methanol.

The reaction of a 2,2-diphenyl-1-picrylhydrazyl radical (dpph˙) with phenols carried out in alcohols is a frequently used assay for estimation of the antiradical activity of phenolic compounds. The rates of reactions of dpph˙ with five phenols (ArOH: unsubstituted phenol, 4-hydroxyacetophenone, two calix[4]resorcinarenes and baicalein) measured in methanol indicate the different kinetics of the process for very diluted phenols compared to their non-diluted solutions. This effect was explained as dependent on the ratio [ArO]/[ArOH] and for diluted ArOH corresponds to an increased contribution of much faster electron transfer (ET, ArO/dpph˙) over the Hydrogen Atom Transfer (HAT, ArOH/dpph˙).

Unexpected Role of pH and Microenvironment on the Antioxidant and Synergistic Activity of Resveratrol in Model Micellar and Liposomal Systems.

Experimental and theoretical studies indicate that resveratrol (RSV, dietary polyphenol that effectively reduces cellular oxidative stress) is a good scavenger of hydroxyl, alkoxyl, and peroxyl radicals in homogeneous systems. However, the role of RSV as a chain-breaking antioxidant is still questioned. Here, we describe pH dependent effectiveness of RSV as an inhibitor of peroxidation of methyl linoleate in Triton X-100 micelles and in 1,2-dimyristoyl--glycero-3-phosphocholine (DMPC) liposomes, with the best effectiveness at pH 6 (stoichiometric factors, , are 4.

Antioxidant activity of highly hydroxylated fullerene C and its interactions with the analogue of α-tocopherol.

Polyhydroxylated fullerenes (fullerenols) are excellent free radical scavengers. Despite the large number of reports on their reactions with reactive oxygen species, there is no report on their ability to trap lipid peroxyl radicals and act as chain-breaking antioxidants. In this work we studied the effect of fullerenol C(OH) on the kinetics of peroxidation of polyunsaturated fatty acid ester (methyl linoleate) dispersed in two model systems that mimic biological systems: Triton X-100 micelles and Large Unilamellar Vesicles, at pH 4, 7 and 10.

Hydroxycinnamyl Derived BODIPY as a Lipophilic Fluorescence Probe for Peroxyl Radicals.

Herein, we describe the synthesis of a fluorescent probe and its use for the detection of peroxyl radicals. This probe is composed of two receptor segments (4-hydroxycinnamyl moieties) sensitive towards peroxyl radicals that are conjugated with a fluorescent reporter, dipyrrometheneboron difluoride (BODIPY), whose emission changes depend on the oxidation state of the receptors. The measurement of the rate of peroxidation of methyl linoleate in a micellar system in the presence of 1.

Antioxidant Activity of Metal Nanoparticles Coated with Tocopherol-Like Residues-The Importance of Studies in Homo- and Heterogeneous Systems.

Functionalized nanoparticles (NPs) attract great attention in pharmacy, diagnostics, and biomedical areas due to benefits like localization and unique interactions of NPs with biocomponents of living cells. In the present paper, we prepared and characterized two kinds of gold nanoparticles (AuNPs) coated with α-tocopherol-like residues: were soluble in non-polar solvents and their antioxidant activity was tested during the peroxidation of a model hydrocarbon in a homogeneous system, whereas nanoparticles were soluble in polar solvents and were applied as antioxidants in micellar and liposomal systems. The effectiveness of is comparable to 2,2,5,7,8-pentamethylchroman-6-ol (PMHC, an analogue of α-tocopherol).