Accumulation of hypoxia-inducible factor-1alpha through a novel electrophilic, thiol antioxidant-sensitive mechanism.
15-deoxy-Delta(12,14)-prostaglandin-J(2) (15d-PGJ(2)) is a peroxisome-activated proliferator receptor-gamma (PPARgamma) agonist which contains an alpha,beta-unsaturated electrophilic ketone involved in nucleophilic addition reactions to thiols. Here we studied its effect on hypoxia-inducible factor-1alpha (HIF-1alpha) in human proximal tubular cells HK-2. 15d-PGJ(2) induced stabilization of HIF-1alpha protein, without affecting HIF-1alpha mRNA levels or proteasome activity, leading to its nuclear accumulation and activation of HIF-induced transcription. Accumulation of HIF-1alpha was unaffected by selective PPARgamma blockade nor mimicked by the PPARgamma agonists ciglitazone and 9,10-dihydro-15d-PGJ(2). N-acetylcysteine, reduced glutathione (GSH) or dithiothreitol (i.e. agents that act as thiol reducing agents and/or increase the GSH content), but not reactive oxygen species (ROS) scavengers, prevented 15d-PGJ(2)-induced HIF-1alpha accumulation whereas the inhibitor of GSH synthesis buthionine sulfoximine cooperated with 15d-PGJ(2) to accumulate HIF-1alpha. Finally, HIF-1alpha expression was increased by the electrophilic alpha,beta-unsaturated compounds acrolein and PGA(2), but not by 9,10-dihydro-15d-PGJ(2), which lacks the electrophilic cyclopentenone moiety. Taken together, these results point out to a new mechanism to increase pharmacologically the cell levels of HIF-1alpha through the electrophilic reaction of alpha,beta-unsaturated ketones with thiol groups.
Departamento de Fisiología, Facultad de Medicina, Universidad de Alcalá, Alcalá de Henares, 28871 Madrid, Spain.
Gemma
G
Olmos
Isabel
I
Conde
Isabel
I
Arenas
Luis
L
Del Peso
Carmen
C
Castellanos
Manuel O
MO
Landazuri
Javier
J
Lucio-Cazana
D000975:Antioxidants / Q000494:pharmacology; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D005978:Glutathione / Q000037:antagonists & inhibitors / Q000494:pharmacology; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000096:biosynthesis* / Q000235:genetics; D007668:Kidney / Q000187:drug effects / Q000378:metabolism; D007687:Kidney Tubules, Proximal / Q000187:drug effects / Q000378:metabolism*; D047495:PPAR gamma / Q000819:agonists / Q000378:metabolism; D015230:Prostaglandin D2 / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000494:pharmacology; D061988:Proteasome Inhibitors; D017382:Reactive Oxygen Species / Q000378:metabolism; D019163:Reducing Agents / Q000494:pharmacology; D013438:Sulfhydryl Compounds / Q000494:pharmacology; D014158:Transcription, Genetic
C097240:15-deoxy-delta(12,14)-prostaglandin J2; D000975:Antioxidants; C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D047495:PPAR gamma; D061988:Proteasome Inhibitors; D017382:Reactive Oxygen Species; D019163:Reducing Agents; D013438:Sulfhydryl Compounds; D005978:Glutathione; D015230:Prostaglandin D2