title: Pro-oxidant effect of ALA is implicated in mitochondrial dysfunction of HepG2 cells.
abstract: Heme biosynthesis begins in the mitochondrion with the formation of delta-aminolevulinic acid (ALA). In acute intermittent porphyria, hereditary tyrosinemia type I and lead poisoning patients, ALA is accumulated in plasma and in organs, especially the liver. These diseases are also associated with neuromuscular dysfunction and increased incidence of hepatocellular carcinoma. Many studies suggest that this damage may originate from ALA-induced oxidative stress following its accumulation. Using the MnSOD as an oxidative stress marker, we showed here that ALA treatment of cultured cells induced ROS production, increasing with ALA concentration. The mitochondrial energetic function of ALA-treated HepG2 cells was further explored. Mitochondrial respiration and ATP content were reduced compared to control cells. For the 300 μM treatment, ALA induced a mitochondrial mass decrease and a mitochondrial network imbalance although neither necrosis nor apoptosis were observed. The up regulation of PGC-1, Tfam and ND5 genes was also found; these genes encode mitochondrial proteins involved in mitochondrial biogenesis activation and OXPHOS function. We propose that ALA may constitute an internal bioenergetic signal, which initiates a coordinated upregulation of respiratory genes, which ultimately drives mitochondrial metabolic adaptation within cells. The addition of an antioxidant, Manganese(III) tetrakis(1-methyl-4-pyridyl)porphyrin (MnTMPyP), resulted in improvement of maximal respiratory chain capacity with 300 μM ALA. Our results suggest that mitochondria, an ALA-production site, are more sensitive to pro-oxidant effect of ALA, and may be directly involved in pathophysiology of patients with inherited or acquired porphyria.
authors.affiliation: LUNAM Université, INSERM UMR 1063, IBIS, IRIS, rue des capucins, 49100 Angers, France. Electronic address: laafi_jihane@hotmail.com.
authors.forename: Jihane
authors.initials: J
authors.lastname: Laafi
authors.affiliation: LUNAM Université, INSERM UMR 1063, IBIS, IRIS, rue des capucins, 49100 Angers, France; Centre Hospitalier Universitaire, Département de Biochimie et Génétique, IBIS, IRIS, rue des capucins, 49100 Angers, France. Electronic address: chhomedan@chu-angers.fr.
authors.forename: Chadi
authors.initials: C
authors.lastname: Homedan
authors.affiliation: LUNAM Université, INSERM UMR 1063, IBIS, IRIS, rue des capucins, 49100 Angers, France. Electronic address: caroline.jacques@univ-angers.fr.
authors.forename: Caroline
authors.initials: C
authors.lastname: Jacques
authors.affiliation: Centre Hospitalier Universitaire, Département de Biochimie et Génétique, IBIS, IRIS, rue des capucins, 49100 Angers, France; CNRS UMR 6214 - INSERM 1083, IBIS, IRIS, rue des capucins, 49100 Angers, France. Electronic address: nagueguen@chu-angers.fr.
authors.forename: Naig
authors.initials: N
authors.lastname: Gueguen
authors.affiliation: Assistance Publique Hôpitaux de Paris, Centre Français des Porphyries, Hôpital Louis Mourier, Université Paris Diderot, 178 rue des Renouillers, 92700 Colombes, France; INSERM U773, Centre de Recherche Biomédicale Bichat-Beaujon, Paris, France; Université Paris Diderot, 5 Rue Thomas Mann, 75013 Paris, France. Electronic address: caroline.schmitt@lmr.aphp.fr.
authors.forename: Caroline
authors.initials: C
authors.lastname: Schmitt
authors.affiliation: Assistance Publique Hôpitaux de Paris, Centre Français des Porphyries, Hôpital Louis Mourier, Université Paris Diderot, 178 rue des Renouillers, 92700 Colombes, France; INSERM U773, Centre de Recherche Biomédicale Bichat-Beaujon, Paris, France; Université Paris Diderot, 5 Rue Thomas Mann, 75013 Paris, France. Electronic address: herve.puy@bch.aphp.fr.
authors.forename: Hervé
authors.initials: H
authors.lastname: Puy
authors.affiliation: Centre Hospitalier Universitaire, Département de Biochimie et Génétique, IBIS, IRIS, rue des capucins, 49100 Angers, France; CNRS UMR 6214 - INSERM 1083, IBIS, IRIS, rue des capucins, 49100 Angers, France. Electronic address: pareynier@chu-angers.fr.
authors.forename: Pascal
authors.initials: P
authors.lastname: Reynier
authors.affiliation: LUNAM Université, INSERM UMR 1063, IBIS, IRIS, rue des capucins, 49100 Angers, France. Electronic address: carmen.martinez@univ-angers.fr.
authors.forename: Maria
authors.initials: M
authors.lastname: Carmen Martinez
authors.affiliation: LUNAM Université, INSERM UMR 1063, IBIS, IRIS, rue des capucins, 49100 Angers, France; Centre Hospitalier Universitaire, Département de Biochimie et Génétique, IBIS, IRIS, rue des capucins, 49100 Angers, France. Electronic address: yves.malthiery@univ-angers.fr.
authors.forename: Yves
authors.initials: Y
authors.lastname: Malthièry
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000622:Aminolevulinic Acid / Q000378:metabolism / Q000494:pharmacology*; D000975:Antioxidants / Q000494:pharmacology; D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D042967:Electron Transport Complex I / Q000235:genetics / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D056945:Hep G2 Cells; D006801:Humans; D007473:Ion Channels / Q000235:genetics / Q000378:metabolism; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D008665:Metalloporphyrins / Q000494:pharmacology; D018613:Microscopy, Confocal; D008928:Mitochondria / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism; D016877:Oxidants / Q000378:metabolism / Q000494:pharmacology*; D010101:Oxygen Consumption / Q000187:drug effects; D011524:Protoporphyrins / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D000071246:Uncoupling Protein 2
chemical_list: D000975:Antioxidants; D004268:DNA-Binding Proteins; D007473:Ion Channels; D008665:Metalloporphyrins; D024101:Mitochondrial Proteins; C502230:Mn(III) 5,10,15,20-tetrakis(N-methylpyridinium-2-yl)porphyrin; D016877:Oxidants; D011524:Protoporphyrins; D017382:Reactive Oxygen Species; C499631:TFAM protein, human; D014157:Transcription Factors; D000071246:Uncoupling Protein 2; D000622:Aminolevulinic Acid; D000255:Adenosine Triphosphate; C028025:protoporphyrin IX; D013482:Superoxide Dismutase; C481838:MT-ND5 protein, human; D042967:Electron Transport Complex I
keywords: 5-Aminolevulinic acid; Energetic dysfunctions; Mitochondria; Oxidative phosphorylation; Oxidative stress; Respiratory chain