Increased levels of 4-hydroxynonenal in human monocytes fed with malarial pigment hemozoin A possible clue for hemozoin toxicity (original) (raw)
Related papers
Biochimica et Biophysica Acta (BBA) - Molecular Basis of Disease, 1996
Upon stimulation, inactive subunits of monocyte NADPH oxidase (NOX) are assembled in the membrane to generate the active enzyme responsible for oxidative burst. Phosphorylation of the 47 kDa NOX cytoplasmic subunit (47 kDa band) by protein kinase C (PKC) is important for NOX assembly and activation. Alternatively, NOX is activated in vitro by sodium dodecyl sulfate (SDS) or amphiphiles via a phosphorylation-independent mechanism. Previous data indicate that phagocytosis of malarial pigment hemozoin inhibits oxidative burst and PKC activity (Schwarzer, E., Turrini, F., Giribaldi, G., Cappadoro, M. and Arese, P. (1993) Biochim. Biophys. Acta, 1181, 51-54). We show here that SDS-stimulated NOX activity and phorbol 12-myristate 13-acetate (PMA)-induced oxidative burst dropped by 54% and 46% of control values 2 h after hemozoin phagocytosis, respectively. SDS-stimulated NOX activity remained roughly constant until 12 h, whereas oxidative burst dropped further by approx. 60% and 75% of control values 6 h and 12 h after hemozoin phagocytosis. Reconstitution experiments indicate that damage was localized to cytosolic NOX subunit(s). Membrane assembly of active NOX was defective in PMA-(PKC-dependent stimulation) and FMLP-(PKC-dependent and independent stimulation) stimulated hemozoin-fed monocytes. Labeling experiments with [32p]orthophosphate or [',/-32P]ATP showed that endogenous PKC-dependent phosphorylation of the 47 kDa band was unaffected 12 h and impaired only 24 h after hemozoin phagocytosis. Thus, only long-term inhibition of NOX may additionally depend on superimposed PKC inhibition.
Blood, 2010
Inhibition of erythropoiesis in malaria anemia: role of hemozoin and http://bloodjournal.hematologylibrary.org/content/116/20/4328.full.html Updated information and services can be found at: (376 articles) Red Cells, Iron, and Erythropoiesis Articles on similar topics can be found in the following Blood collections http://bloodjournal.hematologylibrary.org/site/misc/rights.xhtml#repub\_requests Information about reproducing this article in parts or in its entirety may be found online at: http://bloodjournal.hematologylibrary.org/site/misc/rights.xhtml#reprints Information about ordering reprints may be found online at: http://bloodjournal.hematologylibrary.org/site/subscriptions/index.xhtml Information about subscriptions and ASH membership may be found online at: Severe malaria anemia is characterized by inhibited/altered erythropoiesis and presence of hemozoin-(HZ)-laden bonemarrow macrophages. HZ mediates peroxidation of unsaturated fatty acids and production of bioactive aldehydes such as 4-hydroxynonenal (HNE). HZ-laden human monocytes inhibited growth of cocultivated human erythroid cells and produced HNE that diffused to adjacent cells generating HNE-protein adducts. Cocultivation with HZ or treatment with low micromolar HNE inhibited growth of ery-throid cells interfering with cell cycle without apoptosis. After HZ/HNE treatment, 2 critical proteins in cell-cycle regulation, p53 and p21, were increased and the retinoblastoma protein, central regulator of G 1 -to-S-phase transition, was consequently hypophosphorylated, while GATA-1, master transcription factor in erythropoiesis was reduced. The resultant decreased expression of cyclin A and D2 retarded cell-cycle progression in erythroid cells and the K562 cell line. As a second major effect, HZ and HNE inhib-ited protein expression of crucial receptors (R): transferrinR1, stem cell factorR, interleukin-3R, and erythropoietinR. The reduced receptor expression and the impaired cell-cycle activity decreased the production of cells expressing glycophorin-A and hemoglobin. Present data confirm the inhibitory role of HZ, identify HNE as one HZ-generated inhibitory molecule and describe molecular targets of HNE in erythroid progenitors possibly involved in erythropoiesis inhibition in malaria anemia. (Blood. 2010;116(20):4328-4337)
2014
Natural hemozoin, nHZ, is avidly phagocytosed in vivo and in vitro by human monocytes. The persistence of the undigested β-hematin core of nHZ in the phagocyte lysosome for long periods of time modifies several cellular immune functions. Here we show that nHZ phagocytosis by human primary monocytes severely impaired their chemotactic motility toward MCP-1, TNF, and FMLP, by approximately 80% each, and their diapedesis across a confluent human umbilical vein endothelial cell layer toward MCP-1 by 457 5%. No inhibition was observed with latex-fed or unfed monocytes. Microscopic inspection revealed polarization defects in nHZ-fed monocytes due to irregular actin polymerization. Phagocytosed nHZ catalyzes the peroxidation of polyunsaturated fatty acids and generation of the highly reactive derivative 4-hydroxynonenal (4-HNE). Similar to nHZ phagocytosis, the exposure of monocytes to in vivocompatible 4-HNE concentrations inhibited cell motility in both the presence and the absence of chemotactic stimuli, suggesting severe impairment of cytoskeleton dynamics. Consequently, 4-HNE conjugates with the cytoskeleton proteins β-actin and coronin-1A were immunochemically identified in nHZ-fed monocytes and mass spectrometrically localized in domains of protein-protein interactions involved in cytoskeleton reorganization and cell motility. The molecular and functional modifications of actin and coronin by nHZ/4-HNE may also explain impaired phagocytosis, another motility-dependent process previously described in nHZ-fed monocytes. Further studies will show whether impaired monocyte motility may contribute to the immunodepression and the frequent occurrence of secondary infections observed in malaria patients.
BioFactors, 2005
In falciparum malaria, rupture of parasitized RBC liberates hemozoin (HZ), polymerized heme that contains and generates lipoperoxidation products. In HZ and HZ-loaded monocytes 4-HNE attained approx. 50 and 15 µM, respectively. In malaria, HZ-loaded monocytes are precursors of dendritic cells (DC). Here, the role of 4-HNE as inhibitor of DC differentiation was examined. 4-HNE in HZ was quantified after derivatization by HPLC. DC were differentiated in vitro from human monocytes supplemented with GM-CSF/IL-4 and analyzed for surface antigens and 4-HNE-adducts by FACScan after labelling with specific antibodies. HZ-loading, or treatment with 4-HNE induced large numbers of 4-HNE-protein-adducts on the monocyte membrane. As low as 10 nM 4-HNE inhibited up-regulation of functionally important DC differentiation markers. 1 µM 4-HNE elicited inhibition of up-regulation of DC differentiation markers as follows: MHC-class I and II, −29% and −40%; CD1a, −16%; CD40, −25%; CD54, −27%; and CD83 (the most important DC differentiation marker), −45%, with no signs of apoptosis.
Malaria Pigment Hemozoin Impairs GM-CSF Receptor Expression and Function by 4-Hydroxynonenal
Antioxidants, 2021
Malarial pigment hemozoin (HZ) generates the lipoperoxidation product 4-hydroxynonenal (4-HNE), which is known to cause dysregulation of the immune response in malaria. The inhibition of granulocyte macrophage colony-stimulating factor (GM-CSF)-dependent differentiation of dendritic cells (DC) by HZ and 4-HNE was previously described in vitro, and the GM-CSF receptor (GM-CSF R) was hypothesised to be a primary target of 4-HNE in monocytes. In this study, we show the functional impact of HZ on GM-CSF R in monocytes and monocyte-derived DC by (i) impairing GM-CSF binding by 50 ± 9% and 65 ± 14%, respectively (n = 3 for both cell types); (ii) decreasing the expression of GM-CSF R functional subunit (CD116) on monocyte’s surface by 36 ± 11% (n = 6) and in cell lysate by 58 ± 16% (n = 3); and (iii) binding of 4-HNE to distinct amino acid residues on CD116. The data suggest that defective DC differentiation in malaria is caused by GM-CSF R dysregulation and GM-CSF R modification by lipope...
The Journal of Immunology, 2004
Acute and chronic Plasmodium falciparum malaria are accompanied by severe immunodepression possibly related to subversion of dendritic cells (DC) functionality. Phagocytosed hemozoin (malarial pigment) was shown to inhibit monocyte functions related to immunity. Hemozoin-loaded monocytes, frequently found in circulation and adherent to endothelia in malaria, may interfere with DC development and play a role in immunodepression. Hemozoin-loaded and unloaded human monocytes were differentiated in vitro to immature DC (iDC) by treatment with GM-CSF and IL-4, and to mature DC (mDC) by LPS challenge. In a second setting, hemozoin was fed to iDC further cultured to give mDC. In both settings, cells ingested large amounts of hemozoin undegraded during DC maturation. Hemozoin-fed monocytes did not apoptose but their differentiation and maturation to DC was severely impaired as shown by blunted expression of MHC class II and costimulatory molecules CD83, CD80, CD54, CD40, CD1a, and lower levels of CD83-specific mRNA in hemozoin-loaded iDC and mDC compared with unfed or latex-loaded DC. Further studies indicated activation of peroxisome proliferator-activated receptor-␥ (PPAR-␥) in hemozoin-loaded iDC and mDC, associated with increased expression of PPAR-␥ mRNA, without apparent involvement of NF-B. Moreover, expression of PPAR-␥ was induced and up-regulation of CD83 was inhibited by supplementing iDC and mDC with plausible concentrations of 15(S)-hydroxyeicosatetraenoic acid, a PPAR-␥ ligand abundantly produced by hemozoin via heme-catalyzed lipoperoxidation.
The Journal of Immunology, 2004
Acute and chronic Plasmodium falciparum malaria are accompanied by severe immunodepression possibly related to subversion of dendritic cells (DC) functionality. Phagocytosed hemozoin (malarial pigment) was shown to inhibit monocyte functions related to immunity. Hemozoin-loaded monocytes, frequently found in circulation and adherent to endothelia in malaria, may interfere with DC development and play a role in immunodepression. Hemozoin-loaded and unloaded human monocytes were differentiated in vitro to immature DC (iDC) by treatment with GM-CSF and IL-4, and to mature DC (mDC) by LPS challenge. In a second setting, hemozoin was fed to iDC further cultured to give mDC. In both settings, cells ingested large amounts of hemozoin undegraded during DC maturation. Hemozoin-fed monocytes did not apoptose but their differentiation and maturation to DC was severely impaired as shown by blunted expression of MHC class II and costimulatory molecules CD83, CD80, CD54, CD40, CD1a, and lower levels of CD83-specific mRNA in hemozoin-loaded iDC and mDC compared with unfed or latex-loaded DC. Further studies indicated activation of peroxisome proliferator-activated receptor-␥ (PPAR-␥) in hemozoin-loaded iDC and mDC, associated with increased expression of PPAR-␥ mRNA, without apparent involvement of NF-B. Moreover, expression of PPAR-␥ was induced and up-regulation of CD83 was inhibited by supplementing iDC and mDC with plausible concentrations of 15(S)-hydroxyeicosatetraenoic acid, a PPAR-␥ ligand abundantly produced by hemozoin via heme-catalyzed lipoperoxidation.
Malarial pigment (haemozoin) : a very active 'inert' substance
Annals of Tropical Medicine And Parasitology, 1997
Malarial pigment (haemozoin; HZ) is generally considered to be a non-toxic, high-molecular-weight storage form of undigested, toxic, host-haemoglobin haem. The available information on HZ indicates that it is a very heterogeneous material. Its exact structure, in terms of constituent proteins (remnants of host globin v. parasite proteins), the type of linkage between the haem moieties (m-oxo haem dimers further aggregated by non-covalent hydrophobic bonds v. mutually independent haematin monomers), iron status in the haem (penta-coordinated , high-spin ferriprotoporphyrin IX v. esa-coordinated , low-spin ferriprotoporphyrin IX), and composition (b-haematin-like structure without functionally relevant proteins or other constituents v. a ferriprotoporphyrin-IX core with aggregated proteins and phospholipids of host and parasite origin) remains a subject of controversy. When ingested by macrophages, HZ is not inert but affects a number of functional parameters. Crude pigment, as present in infected erythrocytes and shed after schizont rupture, may be considered the`natural diet' ingested by macrophages in infected blood. It is a powerful source of radicals that may generate lipoperoxides and derived, toxic hydroxyaldehydes such as 4-hydroxynonenal (HNE). High concentrations of HNE, which have been detected in HZ-fed macrophages, inhibit protein kinase C (PKC). Complexes between HNE and PKC have also been detected in immunoprecipitated PKC from HZ-fed macrophages. HNE-mediated inhibition of PKC (and of other, as yet unidenti® ed enzymes and processes) may explain HZ-mediated effects. HZ-mediated inhibition of NADPH-oxidase, the enzyme responsible for oxidative bursts, may only be partially explained by PKC inhibition. As HZ-laden human and murine macrophages produce increased amounts of tumour necrosis factor-a , interleukins 1 and 6, and macrophage in¯ammatory proteins 1 a and 1 b , HZ-macrophage interactions may contribute to the cytokine-mediated manifestations of malaria.