Cellular prion protein (PrPc) participates in the pathogenesis of prion diseases but its normal function remains unclear. PrPc is expressed on hematopoietic cells, including erythroid precursors. We investigated the role of PrPc in erythropoiesis in vivo with phenylhydrazine-induced acute anemia. Induction of equivalent anemia in wild-type (WT) and Prnp-/- mice resulted in a higher number of circulating reticulocytes, hematocrits and spleen weights in WT mice than in Prnp-/- mice on Days 5 and 7. Examination of bone marrow erythroid precursor cells (Ter119+) on Day 5 revealed no significant differences in the number of these cells between the two types of animals. However, a higher percentage of Ter119+ cells were going through apoptosis in Prnp-/- mice than in WT mice. Plasma erythropoietin (Epo) levels and Epo mRNA in kidneys peaked on Day 3 in response to anemia for both types of animals but rose less in Prnp-/- (5500 pg/ml ) than in WT (18,000 pg/ml) animals. Administration of recombinant human Epo to mice produced an equivalent reticulocyte response in both types of animals suggesting that the potential for erythroid generation is intact in Prnp-/- animals. These observations indicate that PrPc may modulate tissue hypoxia-sensing mechanisms or effect hypoxia target gene expression.
- MeSH
- akutní nemoc MeSH
- erythropoetin krev aplikace a dávkování farmakologie MeSH
- erytroidní prekurzorové buňky fyziologie MeSH
- erytropoéza MeSH
- fenylhydraziny MeSH
- financování organizované MeSH
- hemolytické anemie chemicky indukované krev metabolismus MeSH
- hypoxie metabolismus MeSH
- mutantní kmeny myší MeSH
- myši knockoutované MeSH
- myši MeSH
- oxidancia farmakologie MeSH
- PrPC proteiny fyziologie krev MeSH
- retikulocyty fyziologie účinky léků MeSH
- zvířata MeSH
- Check Tag
- myši MeSH
- zvířata MeSH
The effects of nitroglycerine (NTG) are mediated by liberated nitric oxide (NO) after NTG enzymatic bio-transformation in cells. The aim of this study was to evaluate some products of NTG bio-transformation and their consequences on the redox status of rat erythrocytes and reticulocytes, considering the absence and presence of functional mitochondria in these cells, respectively. Rat erythrocyte and reticulocyte-rich red blood cell (RBC) suspensions were aerobically incubated (2 h, 37 0C) without (control) or in the presence of different concentrations of NTG (0.1, 0.25, 0.5, 1.0 and 1.5 mM). In rat erythrocytes, NTG did not elevate the concentrations of any reactive nitrogen species (RNS). However, NTG robustly increased concentration of methemoglobin (MetHb), suggesting that NTG bio-transformation was primarily connected with hemoglobin (Hb). NTG-induced MetHb formation was followed by the induction of lipid peroxidation. In rat reticulocytes, NTG caused an increase in the levels of nitrite, peroxinitrite, hydrogen peroxide, MetHb and lipid peroxide levels, but it decreased the level of the superoxide anion radical. Millimolar concentrations of NTG caused oxidative damage of both erythrocytes and reticulocytes. These data indicate that two pathways of NTG bio-transformation exist in reticulocytes: one generating RNS and the other connected with Hb (as in erythrocytes). In conclusion, NTG bio-transformation is different in erythrocytes and reticulocytes due to the presence of mitochondria in the latter. .
- MeSH
- erytrocyty cytologie fyziologie účinky léků MeSH
- financování vládou MeSH
- interpretace statistických dat MeSH
- nitroglycerin analogy a deriváty farmakokinetika MeSH
- oxid dusnatý fyziologie chemie MeSH
- oxidace-redukce účinky léků MeSH
- oxidační stres účinky záření MeSH
- potkani Wistar krev MeSH
- retikulocyty cytologie fyziologie účinky léků MeSH
- zvířata MeSH
- Check Tag
- zvířata MeSH
- Publikační typ
- srovnávací studie MeSH
- MeSH
- adeninnukleotidy fyziologie MeSH
- energetický metabolismus účinky léků MeSH
- isosorbiddinitrát metabolismus MeSH
- krysa rodu rattus MeSH
- oxid dusnatý biosyntéza farmakologie MeSH
- retikulocyty metabolismus účinky léků MeSH
- zvířata MeSH
- Check Tag
- krysa rodu rattus MeSH
- zvířata MeSH
- Publikační typ
- srovnávací studie MeSH
Succinylacetone (SA) is an inhibitor of heme synthesis that acts on the enzyme delta-aminolevulinic acid dehydratase. When reticulocytes are incubated with 59Fe-transferrin (59Fe-Tf) in the presence of SA, there is an accumulation of 59Fe in the mitochondrion and in a cytosolic non-heme intermediate that has been described as a putative Fe transporter (Adams et al, Biochim Biophys Acta 1012:243, 1989). Considering these observations, the present study was designed to examine the intermediates of Fe metabolism in control and SA-treated reticulocytes. This investigation showed that in the cytosol of control cells, most 59Fe was incorporated into hemoglobin (Hb) with a minor amount entering ferritin. In addition, a previously unrecognized cytosolic intermediate was identified (band X) that was absent when heme synthesis was inhibited with SA. Upon reincubation of SA-treated reticulocytes with protoporphyrin IX, band X initially increased in intensity and then decreased later in the incubation. In contrast, when 59Fe-labeled control cells were reincubated in the presence of SA and unlabeled diferric Tf, there was a marked decrease in the intensity of band X. These experiments suggest that component X may be an intermediate involved in the transfer of heme in the cytosol. Alternatively, these data could also be interpreted as indicating that band X may be a short-lived hemoprotein. We have confirmed the presence of an 59Fe-containing molecule in the cytosol of SA-treated reticulocytes (band Y) that is not present in control cells. However, when cells were incubated with 59Fe-Tf plus SA and then chased in the presence of SA and unlabeled diferric Tf, there was no decrease in this cytosolic pool of Fe, suggesting that it was not a intermediate supplying Fe for either ferritin or heme synthesis. Finally, there is little low molecular weight (Mr) Fe in reticulocytes, and our studies suggest that the low-Mr Fe present does not behave as an intermediate. Moreover, after inhibition of heme synthesis with SA, 59Fe in the low-Mr compartment was markedly decreased, suggesting that this component may be heme or a low-Mr heme-containing molecule. Considering the apparent lack of a cytosolic Fe transporter in rabbit reticulocytes, an alternative model of intracellular Fe transport is proposed that does not implicate a potentially toxic intermediate pool of low-Mr Fe complexes.
- MeSH
- biologické modely MeSH
- chelátory železa farmakologie MeSH
- cytosol metabolismus MeSH
- deferoxamin farmakologie MeSH
- hem biosyntéza MeSH
- hemoglobiny biosyntéza MeSH
- heptanoáty farmakologie MeSH
- inhibitory enzymů farmakologie MeSH
- kompartmentace buňky MeSH
- králíci MeSH
- krevní proteiny metabolismus MeSH
- membránové proteiny metabolismus MeSH
- mitochondrie metabolismus MeSH
- porfobilinogensynthasa antagonisté a inhibitory metabolismus MeSH
- protoporfyriny metabolismus MeSH
- retikulocyty chemie účinky léků ultrastruktura MeSH
- transferin metabolismus MeSH
- železo analýza metabolismus MeSH
- zvířata MeSH
- Check Tag
- králíci MeSH
- zvířata MeSH
- Publikační typ
- práce podpořená grantem MeSH
