The protective role of localized nitric oxide production during inflammation may be mediated by the heme oxygenase-1/carbon monoxide pathway

Nitric oxide (NO) is an important part of the host defense mechanism; however, it displays both pro- and anti-inflammatory properties depending on its location and concentration. Importantly, excessive or inappropriate NO production can cause tissue damage. Systemic and local administration of NO synthase (NOS) inhibitors ameliorates and may exacerbate the inflammatory response, respectively. Here, we used a carrageenan-induced pleurisy model of acute inflammation in rats to confirm the location-dependent effects of NO and investigate the underlying mechanisms. As expected, localized suppression of NO production exacerbated inflammation, as evidenced by increased pleural exudate volumes and leukocyte counts and enhanced activity of enzymes related to oxidative stress. In contrast, local NO supplementation reduced leukocyte infiltration, vascular permeability, and the activity of oxidative stress-related enzymes. Interestingly, inhibition of heme oxygenase-1 (HO-1) reversed the anti-inflammatory effects of localized NO production, while the addition of hemin (HO-1 substrate) or carbon monoxide (CO; HO-1 metabolite) decreased leukocyte migration and exudation. Together, these findings confirm a protective role for NO at the inflammatory site, which appears to be mediated via NOS induction of the HO-1/CO pathway. Thus, NO supplementation may be a potential new treatment for oxidative stress-associated inflammatory diseases.     

Blockage of spontaneous Ca2+ oscillation causes cell death in intraerythrocitic Plasmodium falciparum

Malaria remains one of the world's most important infectious diseases and is responsible for enormous mortality and morbidity. Resistance to antimalarial drugs is a challenging problem in malaria control. Clinical malaria is associated with the proliferation and development of Plasmodium parasites in human erythrocytes. Especially, the development into the mature forms (trophozoite and schizont) of Plasmodium falciparum (P. falciparum) causes severe malaria symptoms due to a distinctive property, sequestration which is not shared by any other human malaria. Ca(2+) is well known to be a highly versatile intracellular messenger that regulates many different cellular processes. Cytosolic Ca(2+) increases evoked by extracellular stimuli are often observed in the form of oscillating Ca(2+) spikes (Ca(2+) oscillation) in eukaryotic cells. However, in lower eukaryotic and plant cells the physiological roles and the molecular mechanisms of Ca(2+) oscillation are poorly understood. Here, we showed the observation of the inositol 1,4,5-trisphospate (IP(3))-dependent spontaneous Ca(2+) oscillation in P. falciparum without any exogenous extracellular stimulation by using live cell fluorescence Ca(2+) imaging. Intraerythrocytic P. falciparum exhibited stage-specific Ca(2+) oscillations in ring form and trophozoite stages which were blocked by IP(3) receptor inhibitor, 2-aminoethyl diphenylborinate (2-APB). Analyses of parasitaemia and parasite size and electron micrograph of 2-APB-treated P. falciparum revealed that 2-APB severely obstructed the intraerythrocytic maturation, resulting in cell death of the parasites. Furthermore, we confirmed the similar lethal effect of 2-APB on the chloroquine-resistant strain of P. falciparum. To our best knowledge, we for the first time showed the existence of the spontaneous Ca(2+) oscillation in Plasmodium species and clearly demonstrated that IP(3)-dependent spontaneous Ca(2+) oscillation in P. falciparum is critical for the development of the blood stage of the parasites. Our results provide a novel concept that IP(3)/Ca(2+) signaling pathway in the intraerythrocytic malaria parasites is a promising target for antimalarial drug development.     

Discrimination of genotoxic and non-genotoxic hepatocarcinogens by statistical analysis based on gene expression profiling in the mouse liver as determined by quantitative real-time PCR

The general aim of the present study is to discriminate between mouse genotoxic and non-genotoxic hepatocarcinogens via selected gene expression patterns in the liver as analyzed by quantitative real-time PCR (qPCR) and statistical analysis. qPCR was conducted on liver samples from groups of 5 male, 9-week-old B6C3F(1) mice, at 4 and 48h following a single intraperitoneal administration of chemicals. We quantified 35 genes selected from our previous DNA microarray studies using 12 different chemicals: 8 genotoxic hepatocarcinogens (2-acetylaminofluorene, 2,4-diaminotoluene, diisopropanolnitrosamine, 4-dimethylaminoazobenzene, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, N-nitrosomorpholine, quinoline and urethane) and 4 non-genotoxic hepatocarcinogens (1,4-dichlorobenzene, dichlorodiphenyltrichloroethane, di(2-ethylhexyl)phthalate and furan). A considerable number of genes exhibited significant changes in their gene expression ratios (experimental group/control group) analyzed statistically by the Dunnett's test and Welch's t-test. Finally, we distinguished between the genotoxic and non-genotoxic hepatocarcinogens by statistical analysis using principal component analysis (PCA) of the gene expression profiles for 7 genes (Btg2, Ccnf, Ccng1, Lpr1, Mbd1, Phlda3 and Tubb2c) at 4h and for 12 genes (Aen, Bax, Btg2, Ccnf, Ccng1, Cdkn1a, Gdf15, Lrp1, Mbd1, Phlda3, Plk2 and Tubb2c) at 48h. Seven major biological processes were extracted from the gene ontology analysis: apoptosis, the cell cycle, cell proliferation, DNA damage, DNA repair, oncogenes and tumor suppression. The major, biologically relevant gene pathway suggested was the DNA damage response pathway, resulting from signal transduction by a p53-class mediator leading to the induction of apoptosis. Eight genes (Aen, Bax, Btg2, Ccng1, Cdkn1a, Gdf15, Phlda3 and Plk2) that are directly associated with Trp53 contributed to the PCA. The current findings demonstrate a successful discrimination between genotoxic and non-genotoxic hepatocarcinogens, using qPCR and PCA, on 12 genes associated with a Trp53-mediated signaling pathway for DNA damage response at 4 and 48 h after a single administration of chemicals.     

The content and distribution of steryl ferulates in wheat produced in Japan

Oryzanol contained in rice bran is a complex mixture of steryl ferulates (SFs) with many identified health benefits. Recently, SF has been shown to exist in other cereals such as wheat, rye, and corn. In this study, SFs in several wheats produced in Japan were analyzed. For instance, SF content of whole wheat grain, Yumekaori (Japan) was 15.2 ± 1.4 mg-oryzanol-equivalent/100 g grain, while that of the imported one, 1CW (Canada) was 11.4 ± 1.3 mg-oryzanol-equivalent/100 g grain. The main SF components in the examined wheats were campesteryl ferulate, campestanyl ferulate, and sitostanyl ferulate. SF distribution in whole wheat grain was investigated using 14 fractions produced by a conventional test milling machine. SF was intensively accumulated in the four bran fractions (24 ? 95 mg-oryzanol-equivalent/100 g bran fraction). These results suggest that the wheat bran would be an important source of SF.     

Effect of 15-deoxy-delta12,14-prostaglandin J2 on IL-1beta-induced expression of epithelial neutrophil-activating protein-78 in human endothelial cells

Epithelial neutrophil-activating peptide-78 (ENA-78) is a member of CXC chemokines. It is produced by endothelial cells stimulated with interleukin-1 (IL-1), along with other CXC chemokines such as IL-8 and growth-related oncogene protein-alpha (GRO-alpha). IL-1-induced ENA-78 production by endothelial cells may be important for the regulation of neutrophil activation. 15-Deoxy-Delta(12,14)-prostaglandin J(2) (15d-PGJ(2)) is a natural ligand for peroxisome proliferator-activated receptor-gamma (PPAR-gamma) and affects the expression of various genes. We examined the effect of 15d-PGJ(2) on the expression of ENA-78 in cultured endothelial cells stimulated with IL-1beta. 15d-PGJ(2) inhibited the IL-1beta-induced expression of ENA-78, but not the expression of IL-8 or GRO-alpha in response to IL-1. Ciglitazone, another agonist for PPAR-gamma, had no effect on the expression of ENA-78, suggesting that 15d-PGJ(2) may inhibit the expression of ENA-78 in a PPAR-gamma-independent manner. 15d-PGJ(2) may modulate inflammatory reactions by regulating the balance of CXC chemokines in endothelial cells.     

Molecular analysis of congenital central hypoventilation syndrome

Congenital central hypoventilation syndrome (CCHS or Ondines curse; OMIM 209880) is a disorder characterized by an idiopathic failure of the automatic control of breathing. CCHS is frequently complicated with neurocristopathies such as Hirschsprungs disease (HSCR). The genes involved in the RET-GDNF signaling and/or EDN3-EDNRB signaling pathways have been analyzed as candidates for CCHS; however, only a few patients have mutations of the RET, EDN3, and GDNF genes. Recently, mutations of the PHOX2B gene, especially polyalanine expansions, have been detected in two thirds of patients. We studied the RET, GDNF, GFRA1, PHOX2A, PHOX2B, HASH-1, EDN1, EDN3, EDNRB, and BDNF genes in seven patients with isolated CCHS and three patients with HSCR. We detected polyalanine expansions and a novel frameshift mutation of the PHOX2B gene in four patients and one patient, respectively. We also found several mutations of the RET, GFRA1, PHOX2A, and HASH-1 genes in patients with or without mutations of the PHOX2B gene. Our study confirmed the prominent role of mutations in the PHOX2B gene in the pathogenesis of CCHS. Mutations of the RET, GFRA1, PHOX2A, and HASH-1 genes may also be involved in the pathogenesis of CCHS. To make clear the pathogenesis of CCHS, the analysis of more cases and further candidates concerned with the development of the autonomic nervous system is required.     

Cytokinesis arrest and nuclear fission in low density populations of trichomonad protozoan

Cell growth of anaerobic protozoan Tritrichomonas foetus was analyzed. This protozoan usually proliferates in extremely high density, but protozoan parasites were dispersed uniformly in F-bouillon medium and cell division stopped temporarily. However, nuclear fission continued and giant polynucleated cells formed. Later, cell division resumed and cells returned to normal form. In conditioned medium, cytokinesis of the dispersed parasites did not stop. Results indicated that T. foetus cells secreted an extracellular factor that influenced cytokinesis.     

Oxidative DNA damage (8-hydroxydeoxyguanosine) and body iron status: a study on 2507 healthy people

To clarify the relationship of oxidative stress and body iron status, we detected urinary 8-hydroxydeoxyguanosine (8-OHdG) as a biomarker of oxidative DNA damage, and measured serum ferritin and total iron-binding capacity (TIBC), both reflecting body iron store, on 2507 healthy people aged between 22 and 89 years (males, 1253; females, 1254). The urinary 8-OHdG excretion of males showed almost no change with age, but the excretion of premenopausal females was lower than that of males, whereas postmenopausal females excreted significantly more than males. The values of serum ferritin showed no remarkable change with age in males, but increased gradually in postmenopausal females without iron loss due to bleeding, although the males' values remained higher than those of females at all ages (p<.05). On the other hand, the values of TIBC remained within the narrow limits in males, regardless of age, whereas those of females always stayed at a higher level than the males (p<.05). Conclusively, urinary 8-OHdG correlated with serum ferritin positively and with TIBC inversely, which suggested that body iron status would control the generation of 8-OHdG in vivo. After all, the increase of urinary 8-OHdG excretion in postmenopausal females may be caused by the decrease of body iron loss.