Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:1.6.99.1 (NADPH-diaphorase)
3,903 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two isoforms of the enzyme heme oxygenase are expressed in distinct populations of neurons in the brain. These enzymes catalyse the oxidative cleavage of heme to the cellular antioxidant biliverdin resulting in the release of carbon monoxide in the process. Both heme and carbon monoxide may play important roles in regulating the nitric oxide-cyclic guanosine monophosphate signal transduction system. Thus we have examined the distributions of both isoforms of heme oxygenase in the rat brain, and compared their localizations with that of nitric oxide synthase determined with the NADPH-diaphorase histochemical technique. Heme oxygenase-1 is highly expressed in a few select populations of neurons including cells in the hilus of the dentate gyrus, in the hypothalamus, cerebellum and brainstem. This enzyme appears to be coexpressed with nitric oxide synthase only in a few cells in the dentate gyrus. Heme oxygenase-2 is much more widely expressed. It is present in mitral cells in the olfactory bulb, pyramidal cells in the cortex and hippocampus, granule cells in the dentate gyrus, many neurons in the thalamus, hypothalamus, cerebellum and caudal brainstem. However, only some of these labelled neurons also displayed nitric oxide synthase. Instead, many neurons expressing heme oxygenase-2 correspond to those known to express high levels of the hemoprotein soluble guanylyl cyclase. These results suggest that heme oxygenase may play a role in modulating guanylyl cyclase independent of nitric oxide synthase. This may result from regulation of intracellular heme and carbon monoxide levels by the heme oxygenase system.
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PMID:Brain heme oxygenase isoenzymes and nitric oxide synthase are co-localized in select neurons. 753 81

Western blot analysis using several antibodies showed that rat spinal cord contained abundant immunostainable heme oxygenase-2 (HO-2) and barely detectable levels of heme oxygenase-1 (HO-1). Anti-HO-2 antibody stained large anterior horn motoneurones and numerous smaller neurons throughout spinal cord gray matter including the dorsal root entry zone. HO-2+ astrocytes were not evident in gray matter although their presence cannot be ruled out. The distribution of HO-2+ neurons was compared with the distribution of cells containing NADPH-diaphorase (NADPH-d) activity, a marker for nitric oxide synthase. NADPH-d activity was restricted to far fewer neurons, many of which were close to the central canal and dorsal root entry zone.
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PMID:Differential localization of heme oxygenase and NADPH-diaphorase in spinal cord neurons. 763 2

In the course of our studies on the local blood flow modulation in the NMRI-mouse placenta we have focussed on regulatory pathways involving recently appreciated gaseous messenger molecules nitric oxide (NO) and carbon monoxide (CO), which are generated by NO synthase (NOS) and heme oxygenase (HO)-2, respectively. The distribution of NOS was investigated by immunohistochemistry using an antiserum to the neuronal isoform (NOS-I) and by NADPH diaphorase (NADPHd) histochemistry, supplemented with procedures (permanganate and formaldehyde method) serving to enhance the specificity of the enzyme histochemical method for NOS visualization. HO-2 was demonstrated immunohistochemically. In addition, cyclic guanosine monophosphate (cGMP)-forming soluble guanylate cyclase (sGC) and dehydrogenases generating the NOS co-substrate NADPH were analysed either by immunohistochemistry or enzyme histochemistry. NOS-I immunostaining was observed in the intraplacental visceral yolk sac epithelial cells but not in the placenta and extraplacental visceral epithelial yolk sac cells. Co-localization of NOS-I immunolabeling and NOS-associated NADPHd was exclusively found in the intraplacental visceral epithelial cells, while NADPHd activity not associated to NOS was present in other placental and extraplacental cells additionally analysed for control reasons. HO-2 and sGC immunoreactivity could not be detected in the placenta including the intraplacental visceral epithelial cells but were expressed in several extraplacental cells. Dehydrogenases producing the NOS co-substrate NADPH were present in the intraplacental visceral epithelium as well as in other placental and extraplacental cells. Since the intraplacental visceral epithelial yolk sac layer closely accompanies large fetal blood vessels entering the placental labyrinth from the chorionic plate it may be assumed that NO, generated by the NADPH-consuming NOS-I in the intraplacental yolk sac epithelium, acts to regulate the blood flow by relaxing smooth muscle cells in the wall of these fetal vessels. The lack of immunoreactivity to the NO-effector molecule sGC may be due to methodological reasons. The absence of the HO-2/CO system suggests its insignificant role as a potential gas signaling pathway in the vascular smooth muscle system of the intraplacental visceral yolk sac of mice.
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PMID:Nitric oxide synthase I immunoreactivity and NOS-associated NADPHd histochemistry in the visceral epithelial cells of the intraplacental mouse yolk sac. 873 2

We have previously shown that exposure of rats to constant light (LL) induced a decrease in NO synthase (NOS) activity in the pineal gland. We report here that the use of the sensitive technique of RT-PCR has demonstrated that mRNA for neuronal NOS is present in the pineal, and that it is photoneurally regulated. There was a marked decrease in pineal neuronal NOS mRNA levels in continuous light conditions, similar to the changes seen in NOS enzyme activity. Inducible NOS was not present in the pineal, and there was evidence that the photoregulatable form was not endothelial NOS. The mRNA for two isoforms of heme oxygenase, the enzyme responsible for the generation of the putative neuromodulator carbon monoxide, was also present in the pineal, but neither isoform was photoregulated. Using immunodetection, it was not possible to identify the presence of NOS protein, other than to a minimal extent, even though NOS activity was clearly present. NADPH-diaphorase staining and in situ hybridization were carried out in an attempt to identify the precise location of neuronal NOS message. A strong NADPH-diaphorase reaction was present in sympathetic nerve fibers of the pineal, but pinealocytes showed no or only very weak labelling. In situ hybridization was also unable to identify neuronal NOS message in pinealocytes. These data thus also suggest the possible presence of a pineal-specific NOS isoenzyme.
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PMID:Pineal nitric oxide synthase, but not heme oxygenase, mRNA is suppressed by continuous exposure to light. 1040 74

It has recently been suggested that, in addition to nitric oxide (NO), carbon monoxide (CO) is an important gaseous messenger which might be involved in vertebrate olfactory transduction because its effects include activation of guanylyl cyclase and the formation of cGMP. As there is no information regarding the presence of heme oxygenase-2 -- the constitutive isoform of the heme oxygenase system -- in olfactory neurons of non-rodent species, we have investigated the distribution pattern of heme oxygenase-2 in the olfactory epithelium of the bovine, a representative of macrosmatics. Localization of nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) activity of the olfactory epithelium was compared with heme oxygenase-2 and NO synthase (NOS) immunoreactivities in order to obtain possible hints at functional significance. NADPH-d activity was particularly intense in apical dendrites of receptor neurons. It was also found in Bowman glands and intraepithelial duct cells. Less intense, discrete NADPH-d activity was present also at intermediate and basal levels of the olfactory epithelium, corresponding to the layer of receptor neuron somata and basal cells. While heme oxygenase-2 activity mainly occurred in neuronal perikarya, a very intense NOS immunoreactivity, exclusively for the inducible isoform, was detected in the apical dendrites. Ultrastructurally, NADPH-d histochemistry showed distinct labelling of membranes, in particular of endoplasmic reticulum, mitochondria and nucleus. The coincident localization of the moderate NADPH-d activity and heme oxygenase-2 immunoreactivity in receptor cell perikarya suggest a functional association between NADPH-cytochrome P450 reductase and heme oxygenase-2. In contrast, dendritic localization of NADPH-d activity is topically and possibly functionally related to the presence of the inducible isoform of NOS. The results suggest that both CO and NO may be generated in bovine receptor neurons and thus involved in odorant stimulation. Based on immunocytochemical localization of synthesizing enzymes, NO might be regarded as a direct regulator of transduction related processes while CO might act as a modulator of the initial signal.
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PMID:Heme oxygenase-2 and nitric oxide synthase immunoreactivity of bovine olfactory receptor neurons and a comparison with the distribution of NADPH-diaphorase staining. 1094 53

cGMP and the enzymes, nitric oxide synthase (NOS) and heme oxygenase-1 (HO-1), the products of which stimulate soluble guanylyl cyclase activity, were investigated in cultured dorsal root ganglia (DRG), and nodose ganglia of adult rats. A dramatic increase of cGMP-positive satellite cells in ganglia cultured for 24 or 48 h was observed, particularly in Th8-L2 DRG and in nodose ganglia. These ganglia also contained most NOS-positive neurones, as reflected by NADPH-diaphorase histochemistry. HO-1 immunoreactivity increased in satellite cells, but in different cells to those in which cGMP increased. These results suggest that both NO and CO could be involved in signalling between neurones and satellite cells in sensory ganglia during regeneration.
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PMID:CGMP increases in satellite cells of nitric oxide synthase-containing sensory ganglia. 1105 8

Exposure to fine particulate materials is associated with an increase in mortality rate of cardiovascular diseases. Particles deposited in the lung may affect the vascular system both directly (leaching of soluble components from particles) and indirectly (via cytokines and mediators). The present study addressed cytotoxicity and oxidative stress potency of organic extracts of diesel exhaust particles (OE-DEP) and urban fine particles (OE-UFP) in rat heart microvessel endothelial (RHMVE) cells. The LC(50) values of OE-DEP and OE-UFP were calculated to be 17 and 34 microg/ml, respectively, suggesting that OE-DEP was more cytotoxic than OE-UFP. The viability of OE-DEP- and OE-UFP-exposed cells was ameliorated by N-acetyl-L-cysteine (NAC). The cell monolayer was exposed to 0 (control), 1, 3, and 10 microg/ml OE-DEP for 6 h and mRNA levels of antioxidant enzymes such as heme oxygenase-1 (HO-1), thioredoxin peroxidase 2 (TRPO), glutathione S-transferase P subunit (GST-P), and NADPH dehydrogenase (NADPHD) were quantitated by northern analysis. All those mRNA levels increased dose-dependently with OE-DEP and HO-1 mRNA showed the most marked response to OE-DEP. mRNA levels of those antioxidant enzymes and heat shock protein 72 (HSP72) in OE-DEP-exposed cells were higher than those of OE-UFP-exposed cells as compared at the same concentration. The transcription levels of HO-1 and HSP72 in OE-DEP- and OE-UFP-exposed cells were also reduced by NAC. Those results suggest that the organic fraction of particulate materials in the urban air has a potency to cause oxidative stress to endothelial cells and may be implicated in cardiovascular diseases through functional changes of endothelial cells.
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PMID:Oxidative-stress potency of organic extracts of diesel exhaust and urban fine particles in rat heart microvessel endothelial cells. 1269 5

Intake of inorganic arsenic is known to cause vascular diseases as well as skin lesions and cancer in humans. We investigated the differences in cytotoxicity, uptake rate of arsenic, and gene expression of antioxidative enzymes between arsenite (As(3+))- and arsenate (As(5+))-exposed rat heart microvessel endothelial cells. As(3+) was more cytotoxic than As(5+), and LC(50) values were calculated to be 36 and 220 micro M, respectively. As(3+) (1-25 micro M) increased mRNA levels of antioxidant enzymes such as heme oxygenase-1 (HO-1), thioredoxin peroxidase 2, NADPH dehydrogenase, and glutathione S-transferase P subunit. HO-1 mRNA levels showed the most remarkable increase in response to As(3+). cDNA microarray analysis indicated that there was no prominent difference in arsenic-induced transcriptional changes between As(3+)- and As(5+)-exposed cells, when the cells were exposed to one-fourth the LC(50) concentration of arsenic (9 and 55 micro M for As(3+) and As(5+), respectively). N-acetyl- l-cysteine (NAC) reduced both the cytotoxicity of inorganic arsenic and the HO-1 mRNA level, and buthionine sulfoximine enhanced cytotoxicity of inorganic arsenic. As(3+) was taken up by the endothelial cells 6-7 times faster than As(5+), and the presence of NAC in the culture medium did not change the uptake rate of As(3+). These results suggest that the effects of NAC on arsenic-induced cytotoxicity and oxidative stress were due to the antioxidative role of non-protein thiols and not to chelation of arsenic in the culture medium. The difference in cellular uptake of arsenic between As(3+) and As(5+) appeared not to be due to the ionic charge on arsenic (at physiological pH, trivalent arsenic is neutral whereas pentavalent arsenic is negatively charged). These results suggest that the higher toxicity of As(3+) compared with that of As(5+) is probably due to the faster uptake of As(3+) by endothelial cells, and inorganic arsenic exerts its toxicity at least in part via intracellular oxidative stress.
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PMID:Difference in uptake and toxicity of trivalent and pentavalent inorganic arsenic in rat heart microvessel endothelial cells. 1279 70

Nitric oxide (NO), hydrogen sulfide (H2S), and carbon monoxide (CO) are thought to act as gaseous neuromodulators in the brain across species. For example, in the brain of honeybee Apis mellifera, NO plays important roles in olfactory learning and discrimination, but the existence of H2S- and CO-mediated signaling pathways remains unknown. In the present study, we identified the genes of nitric oxide synthase (NOS), soluble guanylyl cyclase (sGC), cystathionine beta-synthase (CBS), and heme oxygenase (HO) from the honeybee brain. The honeybee brain contains at least one gene for each of NOS, CBS, and HO. The deduced proteins for NOS, CBS, and HO are thought to contain domains to generate NO, H2S, and CO, respectively, and to contain putative Ca2+/calmodulin-binding domains. On the other hand, the honeybee brain contains three subunits of sGC: sGCalpha1, sGCbeta1, and sGCbeta3. Phylogenetic analysis of sGC revealed that Apis sGCalpha1 and sGCbeta1 are closely related to NO- and CO-sensitive sGC subunits, whereas Apis sGCbeta3 is closely related to insect O2-sensitive sGC subunits. In addition, we performed in situ hybridization for Apis NOS mRNA and NADPH-diaphorase histochemistry in the honeybee brain. The NOS gene was strongly expressed in the optic lobes and in the Kenyon cells of the mushroom bodies. NOS activity was detected in the optic lobes, the mushroom bodies, the central body complex, the lateral protocerebral lobes, and the antennal lobes. These findings suggest that NO is involved in various brain functions and that H2S and CO can be endogenously produced in the honeybee brain.
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PMID:Gaseous neuromodulator-related genes expressed in the brain of honeybee Apis mellifera. 1744 1

We previously described the physicochemical characteristics (particle size, adsorbed polynuclear aromatic hydrocarbons [PAHs], oxygen, and metal content) of butadiene soot (BDS) nanoparticles generated during incomplete combustion of the high-volume industrial petrochemical, 1,3-butadiene. We also demonstrated localization of BDS-delivered PAHs to lipid droplets of murine and human respiratory cells in vitro and up-regulation of biotransformation and oxidative stress responses in these cells. Here, the objective was to determine whether inhalation of BDS nanoparticles promotes up-regulation of Phase I biotransformation enzymes, oxidative stress responses, and inflammation in the lungs of mice. Female Balb/c mice exposed to BDS (5 mg/m(3), 4 h/d, 4 d) were killed immediately or 1 day after final exposure; bronchoalveolar lavage fluid (BALF) was collected from the lungs; total RNA was extracted from one lung and histopathology performed on the other. Histopathology and BALF analysis revealed particle-laden macrophages in airways of BDS-treated mice, accompanied by neutrophilia and epithelial damage. Microarray and qRT-PCR analyses revealed up-regulation of (1) aryl hydrocarbon receptor (AhR)-responsive genes: AhR repressor (Ahrr) and cytochrome P450 IA1 and IB1(Cyp1a1, Cyp1b1); (2) oxidative stress response genes: heme oxygenase 1 (Hmox1), nuclear factor erythroid-derived 2-like 2 (Nfe2l2), NADPH dehydrogenase quinone 1 (Nqo1), and glutathione peroxidase 2 (Gpx2); and (3) pro-inflammatory genes: interleukin-6 (IL-6), C-X-C motif ligand 2 (Cxcl2; analog to human IL-8) and ligand 3 (Cxcl3), and granulocyte chemotactic protein (Cxcl6). Inhalation of PAH-rich, petrochemical combustion-derived nanoparticles causes airway inflammation and induces expression of AhR-associated and oxidative stress response genes, as seen in vitro, plus pro-inflammatory genes.
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PMID:Soot nanoparticles promote biotransformation, oxidative stress, and inflammation in murine lungs. 1836 23


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