Short-term effects of pharmacologic HIF stabilization on vasoactive and cytotrophic factors in developing mouse brain.
Hypoxia-inducible transcription factors (HIFs) are crucially involved in brain development and cellular adaptation to hypoxia and ischemia. Degradation of HIF is regulated under normoxia by oxygen-dependent hydroxylation of specific prolyl residues on the labile alpha-subunit by HIF prolyl hydroxylases (PHD). Prolyl-4-hydroxylase inhibitors (PHI) have shown protective effects in vitro and in vivo in adult kidney and brain. The aim of the present study was to investigate in vivo short-term effects of a novel low molecular weight PHI, FG-4497, on HIF-regulated cytotrophic and vasoactive factors in developing mouse brain. Neonatal (P7, n=26) C57/BL6 mice were treated with PHI FG-4497 (30-100 mg/kg, i.p., duration 6 h). Gene expression was analyzed by TaqMan RT-PCR in kidney and developing brain in comparison to controls (NaCl 0.9% and non-treated animals). HIF-1alpha protein was quantified by Western blot analysis. Dose-response studies revealed prominent effects of FG-4497 at a dose of 100 mg/kg as assessed by significant up-regulation of mRNA in both kidney and brain of the following HIF-dependent genes: vascular endothelial growth factor, adrenomedullin and erythropoietin. Organ-specific transcriptional regulation was evident from analysis of hexokinase 2, inducible NO synthase and PHD3 mRNA concentrations. In the brain, HIF-1alpha and HIF-2alpha protein markedly accumulated in response to FG-4497. Besides vasoactive factors, PHI significantly increased cerebral chemokine receptor CXCR-4 mRNA levels. In conclusion, the novel PHI FG-4497 activates HIFs at an early stage of brain maturation and modulates neurotrophic processes known to be crucially involved in brain development and hypoxia-induced brain pathology.
Schneider
Christina
C
Department of Pediatrics, Friedrich-Alexander-University of Erlangen-Nuremberg, Erlangen, Germany.
Krischke
Gudrun
G
Keller
Stephan
S
Walkinshaw
Gail
G
Arend
Michael
M
Rascher
Wolfgang
W
Gassmann
Max
M
Trollmann
Regina
R
D053607:Adrenomedullin / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D051792:Basic Helix-Loop-Helix Proteins / Q000378:metabolism*; D001921:Brain / Q000187:drug effects / Q000254:growth & development* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D004921:Erythropoietin / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D006593:Hexokinase / Q000378:metabolism; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism*; D007668:Kidney / Q000187:drug effects / Q000254:growth & development / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D052247:Nitric Oxide Synthase Type II / Q000378:metabolism; D011393:Procollagen-Proline Dioxygenase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D019718:Receptors, CXCR4 / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D000099162:Endothelial PAS Domain-Containing Protein 1
D053607:Adrenomedullin; D051792:Basic Helix-Loop-Helix Proteins; D004791:Enzyme Inhibitors; D004921:Erythropoietin; D006593:Hexokinase; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D052247:Nitric Oxide Synthase Type II; D011393:Procollagen-Proline Dioxygenase; D012333:RNA, Messenger; D019718:Receptors, CXCR4; D042461:Vascular Endothelial Growth Factor A; D000099162:Endothelial PAS Domain-Containing Protein 1; C514936:CXCR4 protein, mouse; C497443:Hif1a protein, mouse