Iron accumulation has been implicated in degenerative retinal diseases. It can catalyze the production of damaging reactive oxygen species. Previous work has demonstrated iron accumulation in multiple retinal diseases, including age-related macular degeneration and diabetic retinopathy. In mice, systemic knockout of the ferroxidases ceruloplasmin (Cp) and hephaestin (Heph), which oxidize iron, results in retinal iron accumulation and iron-induced degeneration. To determine the role of Heph in the retina, we generated a neural retina-specific Heph knockout on a background of systemic Cp knockout. This resulted in elevated neural retina iron. Conversely, retinal ganglion cells had elevated transferrin receptor and decreased ferritin, suggesting diminished iron levels. The retinal degeneration observed in systemic Cp-/-, Heph-/- mice did not occur. These findings indicate that Heph has a local role in regulating neural retina iron homeostasis, but also suggest that preserved Heph function in either the RPE or systemically mitigates the degeneration phenotype observed in the systemic Cp-/-, Heph-/- mice.

• Klíčová slova
• Age-related macular degeneration, Ceruloplasmin, Ferrous, Hephaestin, Iron, Retina,
• MeSH
• ceruloplasmin genetika   metabolismus   MeSH
• homeostáza MeSH
• makulární degenerace * genetika   MeSH
• membránové proteiny * genetika   MeSH
• myši knockoutované MeSH
• myši MeSH
• retina metabolismus   MeSH
• železo metabolismus   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• ceruloplasmin MeSH
• membránové proteiny * MeSH
• železo MeSH

Iron-induced oxidative stress can cause or exacerbate retinal degenerative diseases. Retinal iron overload has been reported in several mouse disease models with systemic or neural retina-specific knockout (KO) of homologous ferroxidases ceruloplasmin (Cp) and hephaestin (Heph). Cp and Heph can potentiate ferroportin (Fpn) mediated cellular iron export. Here, we used retina-specific Fpn KO mice to test the hypothesis that retinal iron overload in Cp/Heph DKO mice is caused by impaired iron export from neurons and glia. Surprisingly, there was no indication of retinal iron overload in retina-specific Fpn KO mice: the mRNA levels of transferrin receptor in the retina were not altered at 7-10-months age. Consistent with this, levels and localization of ferritin light chain were unchanged. To "stress the system", we injected iron intraperitoneally into Fpn KO mice with or without Cp KO. Only mice with both retina-specific Fpn KO and Cp KO had modestly elevated retinal iron levels. These results suggest that impaired iron export through Fpn is not sufficient to explain the retinal iron overload in Cp/Heph DKO mice. An increase in the levels of retinal ferrous iron caused by the absence of these ferroxidases, followed by uptake into cells by ferrous iron importers, is most likely necessary.

• Klíčová slova
• Age-related macular degeneration, Ceruloplasmin, Ferroportin, Ferrous, Iron, Retina,
• MeSH
• ceruloplasmin genetika   metabolismus   MeSH
• ferroportin MeSH
• myši knockoutované MeSH
• myši MeSH
• přetížení železem * MeSH
• proteiny přenášející kationty * genetika   MeSH
• retina metabolismus   MeSH
• železo metabolismus   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Research Support, N.I.H., Extramural MeSH
• Názvy látek
• ceruloplasmin MeSH
• ferroportin MeSH
• proteiny přenášející kationty * MeSH
• železo MeSH

Ferritin is a storage protein that plays a key role in iron metabolism. In this study, we report on the sequence characterization of a ferritin-coding cDNA in Eisenia andrei earthworms isolated by RT-PCR using degenerated primers, and we suggest the presence of a putative IRE in the 5'-UTR of ferritin mRNA. The obtained ferritin sequence was compared with those of other animals showing sequence and structure homology in consensus sites, including the iron-responsive element (IRE) and ferroxidase centers. Despite the sequence homology in the E. andrei mRNA of ferritin with the sequences of other animals in consensus IRE sites, the presented cytosine in the IRE of E. andrei ferritin in the expected position does not form a conventional bulge. The presence of ferritin in the coelomic fluid of E. andrei was proven by iron staining assay. Moreover, aconitase activity in the coelomic fluid was assessed by aconitase assay, suggesting the presence of an iron regulatory protein. Quantitative analysis revealed changes in the gene expression levels of ferritin in coelomocytes in response to bacterial challenge, reaching the maximum level 8h after the stimulation with both Gram-positive and Gram-negative bacteria.

• MeSH
• akonitáthydratasa analýza   genetika   metabolismus   MeSH
• Bacillus subtilis metabolismus   MeSH
• ceruloplasmin genetika   MeSH
• DNA primery MeSH
• Escherichia coli K12 metabolismus   MeSH
• ferritiny chemie   genetika   MeSH
• klonování DNA MeSH
• komplementární DNA biosyntéza   genetika   izolace a purifikace   MeSH
• konformace nukleové kyseliny MeSH
• messenger RNA chemie   genetika   MeSH
• molekulární sekvence - údaje MeSH
• Oligochaeta genetika   metabolismus   MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• regulace genové exprese MeSH
• RNA genetika   izolace a purifikace   MeSH
• sekvence aminokyselin MeSH
• sekvence nukleotidů MeSH
• sekvenční analýza DNA MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• akonitáthydratasa MeSH
• ceruloplasmin MeSH
• DNA primery MeSH
• ferritiny MeSH
• komplementární DNA MeSH
• messenger RNA MeSH
• RNA MeSH

We studied the effect of iron deficiency, i.e., 24-h preincubation in iron-free medium, and the effect of high level of non-transferrin iron, i.e., the preincubation in ferric citrate medium containing 500 microM ferric citrate, on the expression of DMT1, Dcytb, ferroportin, hephaestin, and ceruloplasmin in various functional types of human cells. The expression of these proteins potentially involved in non-transferrin iron transport across cell membranes was tested on mRNA level by quantitative real-time PCR as well as on protein level by western blot analysis in Caco-2 (colorectal carcinoma), K562 (erythroleukemia), and HEP-G2 (hepatocellular carcinoma) cells. We found that changes in non-transferrin iron availability, i.e., iron deficiency and high level of non-transferrin iron, affect the expression of tested proteins in a cell type-specific manner. We also demonstrated that changes in the expression on mRNA level do not often correlate with relevant changes on protein level.

• MeSH
• buněčná membrána metabolismus   MeSH
• buněčné linie MeSH
• ceruloplasmin genetika   metabolismus   MeSH
• cytochromy typu b genetika   metabolismus   MeSH
• exprese genu * MeSH
• ferroportin MeSH
• kultivační média chemie   MeSH
• lidé MeSH
• membránové proteiny * genetika   metabolismus   MeSH
• oxidoreduktasy genetika   metabolismus   MeSH
• proteiny přenášející kationty genetika   metabolismus   MeSH
• transferin metabolismus   MeSH
• železo metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• ceruloplasmin MeSH
• CYBRD1 protein, human MeSH Prohlížeč
• cytochromy typu b MeSH
• ferroportin MeSH
• HEPH protein, human MeSH Prohlížeč
• kultivační média MeSH
• membránové proteiny * MeSH
• oxidoreduktasy MeSH
• proteiny přenášející kationty MeSH
• solute carrier family 11- (proton-coupled divalent metal ion transporters), member 2 MeSH Prohlížeč
• transferin MeSH
• železo MeSH