Tags

Type your tag names separated by a space and hit enter

Nitric oxide reverses desferrioxamine- and hypoxia-evoked HIF-1alpha accumulation--implications for prolyl hydroxylase activity and iron.
Exp Cell Res. 2005 May 15; 306(1):274-84.EC

Abstract

Hypoxia inducible factor 1 (HIF-1) senses and coordinates cellular responses towards hypoxia. HIF-1 activity is primarily determined by stability regulation of its alpha subunit that is degraded by the 26S proteasome under normoxia due to hydroxylation by prolyl hydroxylases (PHDs) but is stabilized under hypoxia. Besides hypoxia, nitric oxide (NO) stabilizes HIF-1alpha and promotes hypoxia-responsive target gene expression under normoxia. However, in hypoxia, NO attenuates HIF-1alpha stabilization and gene activation. It was our intention to explain the contrasting behavior of NO under hypoxia. We used the iron chelator desferrioxamine (DFX) or hypoxia to accumulate HIF-1alpha in HEK293 cells. Once the protein accumulated, we supplied NO donors and followed HIF-1alpha disappearance. NO-evoked HIF-1alpha destabilization was reversed by proteasomal inhibition or by blocking PHD activity. By using the von Hippel Lindau (pVHL)-HIF-1alpha capture assay, we went on to demonstrate binding of pVHL to HIF-1alpha under DFX/NO but not DFX alone. Showing increased intracellular free iron under conditions of hypoxia/NO compared to hypoxia alone, we assume that increased free iron contributes to regain PHD activity. Variables that allow efficient PHD activation such as oxygen availability, iron content, or cofactor accessibility at that end allow NO to modulate HIF-1alpha accumulation.

Authors+Show Affiliations

Faculty of Medicine, Institute of Biochemistry I, Johann Wolfgang Goethe-University, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't

Language

eng

PubMed ID

15878351

Citation

Callapina, Melvin, et al. "Nitric Oxide Reverses Desferrioxamine- and Hypoxia-evoked HIF-1alpha Accumulation--implications for Prolyl Hydroxylase Activity and Iron." Experimental Cell Research, vol. 306, no. 1, 2005, pp. 274-84.
Callapina M, Zhou J, Schnitzer S, et al. Nitric oxide reverses desferrioxamine- and hypoxia-evoked HIF-1alpha accumulation--implications for prolyl hydroxylase activity and iron. Exp Cell Res. 2005;306(1):274-84.
Callapina, M., Zhou, J., Schnitzer, S., Metzen, E., Lohr, C., Deitmer, J. W., & Brüne, B. (2005). Nitric oxide reverses desferrioxamine- and hypoxia-evoked HIF-1alpha accumulation--implications for prolyl hydroxylase activity and iron. Experimental Cell Research, 306(1), 274-84.
Callapina M, et al. Nitric Oxide Reverses Desferrioxamine- and Hypoxia-evoked HIF-1alpha Accumulation--implications for Prolyl Hydroxylase Activity and Iron. Exp Cell Res. 2005 May 15;306(1):274-84. PubMed PMID: 15878351.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Nitric oxide reverses desferrioxamine- and hypoxia-evoked HIF-1alpha accumulation--implications for prolyl hydroxylase activity and iron. AU - Callapina,Melvin, AU - Zhou,Jie, AU - Schnitzer,Steffen, AU - Metzen,Eric, AU - Lohr,Christian, AU - Deitmer,Joachim W, AU - Brüne,Bernhard, Y1 - 2005/03/20/ PY - 2004/10/25/received PY - 2005/02/17/revised PY - 2005/02/19/accepted PY - 2005/5/10/pubmed PY - 2005/9/2/medline PY - 2005/5/10/entrez SP - 274 EP - 84 JF - Experimental cell research JO - Exp Cell Res VL - 306 IS - 1 N2 - Hypoxia inducible factor 1 (HIF-1) senses and coordinates cellular responses towards hypoxia. HIF-1 activity is primarily determined by stability regulation of its alpha subunit that is degraded by the 26S proteasome under normoxia due to hydroxylation by prolyl hydroxylases (PHDs) but is stabilized under hypoxia. Besides hypoxia, nitric oxide (NO) stabilizes HIF-1alpha and promotes hypoxia-responsive target gene expression under normoxia. However, in hypoxia, NO attenuates HIF-1alpha stabilization and gene activation. It was our intention to explain the contrasting behavior of NO under hypoxia. We used the iron chelator desferrioxamine (DFX) or hypoxia to accumulate HIF-1alpha in HEK293 cells. Once the protein accumulated, we supplied NO donors and followed HIF-1alpha disappearance. NO-evoked HIF-1alpha destabilization was reversed by proteasomal inhibition or by blocking PHD activity. By using the von Hippel Lindau (pVHL)-HIF-1alpha capture assay, we went on to demonstrate binding of pVHL to HIF-1alpha under DFX/NO but not DFX alone. Showing increased intracellular free iron under conditions of hypoxia/NO compared to hypoxia alone, we assume that increased free iron contributes to regain PHD activity. Variables that allow efficient PHD activation such as oxygen availability, iron content, or cofactor accessibility at that end allow NO to modulate HIF-1alpha accumulation. SN - 0014-4827 UR - https://www.unboundmedicine.com/medline/citation/15878351/Nitric_oxide_reverses_desferrioxamine__and_hypoxia_evoked_HIF_1alpha_accumulation__implications_for_prolyl_hydroxylase_activity_and_iron_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S0014-4827(05)00084-4 DB - PRIME DP - Unbound Medicine ER -