Host fibrinogen stably bound to hemozoin rapidly activates monocytes via TLR-4 and CD11b/CD18-integrin: a new paradigm of hemozoin action

Blood ◽  
2011 ◽  
Vol 117 (21) ◽  
pp. 5674-5682 ◽  
Author(s):  
Valentina Barrera ◽  
Oleksii A. Skorokhod ◽  
Denisa Baci ◽  
Giuliana Gremo ◽  
Paolo Arese ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Reactive Oxygen ◽  
Fold Increase ◽  
Eicosatetraenoic Acid ◽  
Cell Contact ◽  
Oxygen Species ◽  
Long Term Effects ◽  
New Paradigm ◽  
Chemotactic Protein

AbstractNatural hemozoin (nHZ), prepared after schizogony, consists of crystalline ferriprotoporphyrin-IX dimers from undigested heme bound to host and parasite proteins and lipids. Phagocytosed nHZ alters important functions of host phagocytes. Most alterations are long-term effects. We show that host fibrinogen (FG) was constantly present (at ∼ 1 FG per 25 000 HZ-heme molecules) and stably bound to nHZ from plasma-cultured parasites. FG was responsible for the rapid 100-fold stimulation of reactive oxygen species production and 50-fold increase of TNF and monocyte chemotactic protein 1 by human monocytes. Those effects, starting within minutes after nHZ cell contact, were because of interaction of FG with FG-receptors TLR4 and integrin CD11b/CD18. Receptor blockage by specific mAbs or removal of FG from nHZ abrogated the effects. nHZ-opsonizing IgGs contribute to the stimulatory response but are not essential for FG effects. Immediate increase in reactive oxygen species and TNF may switch on previously described long-term effects of nHZ, largely because of HZ-generated lipo-peroxidation products 15(S,R)-hydroxy-6,8,11,13-eicosatetraenoic acid and 4-hydroxynonenal. The FG/HZ effects mediated by TLR4/integrins represent a novel paradigm of nHZ activity and allow expansion of nHZ effects to nonphagocytic cells, such as endothelia and airway epithelia, and lead to a better understanding of organ pathology in malaria.

Reactive oxygen species participate in acute renal vasoconstrictor responses induced by ETA and ETB receptors

2008 ◽  
Vol 294 (4) ◽  
pp. F719-F728 ◽  
Author(s):  
Armin Just ◽  
Christina L. Whitten ◽  
William J. Arendshorst
Keyword(s):  
Reactive Oxygen Species ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Long Term Effects ◽  
Vasomotor Tone ◽  
Chronic Stimulation ◽  
Renal Vasoconstriction ◽  
Oxidase Inhibition

Reactive oxygen species (ROS) play important roles in renal vasoconstrictor responses to acute and chronic stimulation by angiotensin II and norepinephrine, as well as in long-term effects of endothelin-1 (ET-1). Little is known about participation of ROS in acute vasoconstriction produced by ET-1. We tested the influence of NAD(P)H oxidase inhibition by apocynin [4 mg·kg−1·min−1, infused into the renal artery (ira)] on ETA and ETB receptor signaling in the renal microcirculation. Both receptors were stimulated by ET-1, ETA receptors by ET-1 during ETB antagonist BQ-788, and ETB by ETB agonist sarafotoxin 6C. ET-1 (1.5 pmol injected ira) reduced renal blood flow (RBF) 17 ± 4%. Apocynin raised baseline RBF (+10 ± 1%, P < 0.001) and attenuated the ET-1 response to 10 ± 2%, i.e., 35 ± 9% inhibition ( P < 0.05). Apocynin reduced ETA-induced vasoconstriction by 42 ± 12% ( P < 0.05) and that of ETB stimulation by 50 ± 8% ( P < 0.001). During nitric oxide (NO) synthase inhibition ( Nω-nitro-l-arginine methyl ester), apocynin blunted ETA-mediated vasoconstriction by 60 ± 8% ( P < 0.01), whereas its effect on the ETB response (by 87 ± 8%, P < 0.001) was even larger without than with NO present ( P < 0.05). The cell-permeable superoxide dismutase mimetic tempol (5 mg·kg−1·min−1 ira), which reduces O2− and may elevate H2O2, attenuated ET-1 responses similar to apocynin (by 38 ± 6%, P < 0.01). We conclude that ROS, O2− rather than H2O2, contribute substantially to acute renal vasoconstriction elicited by both ETA and ETB receptors and to basal renal vasomotor tone in vivo. This physiological constrictor action of ROS does not depend on scavenging of NO. In contrast, scavenging of O2− by NO seems to be more important during ETB stimulation.

scholarly journals Intradialytic granulocyte reactive oxygen species production: a prospective, crossover trial.

1993 ◽  
Vol 4 (2) ◽  
pp. 178-186 ◽  
Author(s):  
J Himmelfarb ◽  
K A Ault ◽  
D Holbrook ◽  
D A Leeber ◽  
R M Hakim
Keyword(s):  
Reactive Oxygen Species ◽  
Reactive Oxygen ◽  
Fold Increase ◽  
Ros Production ◽  
Oxygen Species ◽  
Susceptibility To Infection ◽  
Flow Cytometric ◽  
Ros Formation ◽  
Dialysis Membranes ◽  
Species Production

By the use of flow cytometric techniques, this prospective, randomized crossover study was designed to analyze intradialytic granulocyte reactive oxygen species (ROS) formation in whole blood with complement-activating and noncomplement-activating hollow fiber membranes. Dialysis with a complement-activating membrane resulted in a 6.5-fold increase in granulocyte hydrogen peroxide production 15 min after dialysis initiation and remained significantly elevated (P < 0.01) through the first 30 min with this membrane in comparison to both predialysis values and simultaneous values with a noncomplement-activating membrane. Further studies demonstrated that blood obtained at 15 min with a complement-activating membrane generated significantly less granulocyte ROS production in response to Staphylococcus aureus incubation than blood obtained either predialysis or at the same time in dialysis with a noncomplement-activating membrane. Both complement-activating and noncomplement-activating dialysis membranes caused slightly decreased granulocyte responsiveness to phorbol myristate acetate. It was concluded that hemodialysis with complement-activating membranes results in increased granulocyte ROS production and decreased responsiveness to S. aureus challenge during the dialysis procedure. These results document the potential role of ROS in hemodialysis-associated pathology and susceptibility to infection.

scholarly journals Modifications of proteins of membrane-cytoskeleton complex and production of reactive oxygen species in erythrocytes cryopreserved with polyethylene glycol

2021 ◽  
Vol 67 (2) ◽  
pp. 44-52
Author(s):  
N.G. Zemlianskykh ◽  
◽  
L.O. Babiychuk ◽  
Keyword(s):  
Reactive Oxygen Species ◽  
Polyethylene Glycol ◽  
Protein Profile ◽  
Control Level ◽  
Reactive Oxygen ◽  
Fold Increase ◽  
Oxygen Species ◽  
Membrane Cytoskeleton ◽  
Extreme Factors ◽  
The Stability

Protein modifications in the membrane-cytoskeleton complex (MCC) of human erythrocytes, as well as changes in the intensity of reactive oxygen species (ROS) production upon cell cryopreservation with polyethylene glycol (PEG) were investigated. The protein profile of ghosts of erythrocytes frozen with PEG has common features with both the control and cells frozen without cryoprotectant. PEG makes it possible to restrict the structural rearrangements of the main MCC proteins under the effect of extreme factors and to restrain the amount of high molecular weight polypeptide complexes induced by the protein-cross-linking reagent diamide at the control level, in contrast to cells frozen without a cryoprotectant. However, changes related to the protein peroxiredoxin 2 in ghosts of erythrocytes cryopreserved with PEG are also attributed to cells frozen without a cryoprotectant that may be associated with the activation of oxidative processes. This is evidenced by a 10-fold increase in ROS formation in erythrocytes frozen under PEG protection. Thus, upon cryopreservation of erythrocytes with PEG, certain disorders in MCC proteins may be associated with increased formation of ROS, which may contribute to the disorganization of the structural components of MCC and disrupt the stability of cryopreserved cells under physiological conditions.

Histone Deacetylase Inhibitor (HDACi) PCI-24781 and Bortezomib Result in Synergistic Apoptosis in Hodgkin Lymphoma (HL) and Non-Hodgkin’s Lymphoma (NHL) Cell Lines: Investigation of Cell Death and NFKB-Mediated Pathways.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3589-3589 ◽  
Author(s):  
Savita Bhalla ◽  
Kevin David ◽  
Lauren Mauro ◽  
Sheila Prachand ◽  
Mint Sirisawad ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Cell Death ◽  
Cell Lines ◽  
Reactive Oxygen ◽  
Fold Increase ◽  
Oxygen Species ◽  
Minimal Cell ◽  
Histone 3 ◽  
Dichlorofluorescein Diacetate ◽  
20 Nm

Abstract HDACi block cancer cell proliferation by mechanisms that involve epigenetic gene regulation leading to cell growth arrest, differentiation, and apoptosis. Bortezomib inhibits NFKB signaling and induces apoptosis. Furthermore, anti-tumor activity of HDACi and bortezomib both depend in part on reactive oxygen species (ROS)-mediated pathways. Both have activity in NHL. We reasoned that these agents may be synergistic in part due to their dependence on overlapping pathways. We investigated the biology of PCI-24781, a pan-HDACi currently in clinical trials, and bortezomib both alone, and in combination, in HL (L428) and NHL cell lines (HF1, Ramos, & SUDHL4). Cells were incubated with increasing concentrations of PCI-24781 and bortezomib (0.25–2.0μM and 2.5–20nM, respectively) for 24–72 hour (hr). Apoptosis was determined by fluorescence-activated cell sorting (FACS) using AnnexinV-FITC/propidium iodide (AnnexinV+/PI+) staining. Reactive oxygen species (ROS) were measured by oxidation of 2′7′dichlorofluorescein diacetate (H2DCFDA) to DCF and detected by FACS. Downstream targets of NFKB such as NFKB1, Myc and IL-8 were measured in Ramos using quantitative real time polymerase chain reaction (RT-PCR) following 24 hr incubation of cells with PCI-24781 and bortezomib alone, and in combination. Dose-dependent apoptosis was seen with PCI-24781 and bortezomib alone in all HL and NHL cell lines. IC70 (dose to achieve 70% AnnexinV+/PI+) was 1μM for PCI-24781 and 2μM for L428. With bortezomib, the IC50 was 10nM in Ramos, HF1, and SUDHL4 and 20 nM in L428. The combination of PCI-24781 and bortezomib resulted in synergistic apoptosis (combination index &lt;0.2) in all 3 NHL cell lines (IC80=0.25μM PCI-24781/5nM bortezomib) and L428 (IC80=0.5μM PCI-24781/10nM bortezomib) compared with minimal cell death using each agent alone at those concentrations. Furthermore, immunoblots of L428 and Ramos showed enhanced caspase 3 and caspase 8 cleavage with the combination of PCI-24781 and bortezomib compared to either agent alone, suggesting that the synergy seen was in part caspase-dependent. HL and NHL cell lines showed a 3- to 4-fold increase in ROS with PCI-24781 or bortezomib alone and in combination at 24hr. Moreover, we found that hyperacetylation of histone-3 and histone-4 on immunoblots of cells treated with combination PCI-2478/bortezomib was significantly increased compared to PCI-24781 alone. Finally, we found that in Ramos cells PC-24781/bortezomib together resulted in downregulation of NFKB targets NFKB1 and Myc, but not IL-8. We conclude that PCI-24781 and bortezomib are active in lymphoma cell lines and that the combination results in synergistic apoptosis. Apoptosis was accompanied by caspase activation and synergistic downregulation of the NFkB pathway. These data have important clinical implications for NHL and HL.

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