title: Chronic hypoxia alters mitochondrial composition in human macrophages.
abstract: Hypoxia inducible factors (HIFs) are important mediators of the cellular adaptive response during acute hypoxia. The role of HIF-1 and HIF-2 during prolonged periods of hypoxia, i.e. chronic hypoxia is less defined. Therefore, we used human THP-1 macrophages with a knockdown of either HIF-1α, HIF-2α, or both HIFα-subunits, incubated them for several days under hypoxia (1% O2), and analyzed responses to hypoxia using 2D-DIGE coupled to MS/MS-analysis. Chronic hypoxia was defined as a time point when the early but transient accumulation of HIFα-subunits and mRNA expression of classical HIF target genes returned towards basal levels, with a new steady state that was constant from 72h onwards. From roughly 800 spots, that were regulated comparing normoxia to chronic hypoxia, about 100 proteins were unambiguously assigned during MS/MS-analysis. Interestingly, a number of glycolytic proteins were up-regulated, while a number of inner mitochondrial membrane proteins were down-regulated independently of HIF-1α or HIF-2α. Chronic hypoxic conditions depleted the mitochondrial mass by autophagy, which occurred independently of HIF proteins. Macrophages tolerate periods of chronic hypoxia very well and adaptive responses occur, at least in part, independently of HIF-1α and/or HIF-2α and comprise mitophagy as a pathway of particular importance.
authors.affiliation: Institute of Biochemistry I/ZAFES, Goethe-University Frankfurt, 60590 Frankfurt, Germany.
authors.forename: Dominik Christian
authors.initials: DC
authors.lastname: Fuhrmann
authors.forename: Ilka
authors.initials: I
authors.lastname: Wittig
authors.forename: Heinrich
authors.initials: H
authors.lastname: Heide
authors.forename: Nathalie
authors.initials: N
authors.lastname: Dehne
authors.forename: Bernhard
authors.initials: B
authors.lastname: Brüne
mesh_terms: D001343:Autophagy; D051792:Basic Helix-Loop-Helix Proteins / Q000096:biosynthesis / Q000235:genetics; D015687:Cell Hypoxia / Q000235:genetics; D045744:Cell Line, Tumor; D006019:Glycolysis / Q000235:genetics; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000096:biosynthesis / Q000235:genetics; D008264:Macrophages / Q000378:metabolism* / Q000473:pathology; D008928:Mitochondria / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D024101:Mitochondrial Proteins / Q000096:biosynthesis* / Q000235:genetics; D063306:Mitophagy; D015854:Up-Regulation; D000099162:Endothelial PAS Domain-Containing Protein 1
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D024101:Mitochondrial Proteins; D000099162:Endothelial PAS Domain-Containing Protein 1; C497442:HIF1A protein, human
keywords: 2-dimensional differential gel electrophoresis; 2D-DIGE; ACAD9; AMP-dependent protein kinase; AMPK; ATG; ATP synthase subunit; ATP5; Autophagy; BCL2/adenovirus E1B 19kDa protein-interacting protein 3; BNIP3; BNIP3 ligand; BNIP3L; CAT; CH; FACS; GAPDH; GO; Glycolysis; HIF; Hypoxia-inducible factor; IMMT; LC3; LC–MS/MS; MS/MS; NAO; PHD; acyl-CoA dehydrogenase 9; autophagy-related protein; cathepsin; chronic hypoxia; fluorescence activated cell sorting; gene ontology; glycerinaldehyd-3-phosphat-dehydrogenase; hypoxia inducible factor; microtubule-associated protein 1A/1B-light chain 3; mitochondrial inner membrane protein; nonyl acridine orange; p53; prolyl hydroxylase; tandem mass spectrometry; tumor protein 53