Nutritional regulation of hepatic heme biosynthesis and porphyria through PGC-1alpha.
Inducible hepatic porphyrias are inherited genetic disorders of enzymes of heme biosynthesis. The main clinical manifestations are acute attacks of neuropsychiatric symptoms frequently precipitated by drugs, hormones, or fasting, associated with increased urinary excretion of delta-aminolevulinic acid (ALA). Acute attacks are treated by heme infusion and glucose administration, but the mechanisms underlying the precipitating effects of fasting and the beneficial effects of glucose are unknown. We show that the rate-limiting enzyme in hepatic heme biosynthesis, 5-aminolevulinate synthase (ALAS-1), is regulated by the peroxisome proliferator-activated receptor gamma coactivator 1alpha (PGC-1alpha). Elevation of PGC-1alpha in mice via adenoviral vectors increases the levels of heme precursors in vivo as observed in acute attacks. The induction of ALAS-1 by fasting is lost in liver-specific PGC-1alpha knockout animals, as is the ability of porphyrogenic drugs to dysregulate heme biosynthesis. These data show that PGC-1alpha links nutritional status to heme biosynthesis and acute hepatic porphyria.
Handschin
Christoph
C
Dana-Farber Cancer Institute and Department of Cell Biology, Harvard Medical School, Boston, Massachusetts 02115, USA.
Lin
Jiandie
J
Rhee
James
J
Peyer
Anne-Kathrin
AK
Chin
Sherry
S
Wu
Pei-Hsuan
PH
Meyer
Urs A
UA
Spiegelman
Bruce M
BM
D000624:5-Aminolevulinate Synthetase / Q000378:metabolism; D000818:Animals; D005215:Fasting / Q000378:metabolism*; D000071161:Forkhead Box Protein O1; D051858:Forkhead Transcription Factors; D005822:Genetic Vectors; D005934:Glucagon / Q000378:metabolism; D005947:Glucose / Q000378:metabolism*; D006418:Heme / Q000096:biosynthesis*; D007328:Insulin / Q000378:metabolism; D008099:Liver / Q000201:enzymology* / Q000503:physiopathology; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D008822:Mice, Transgenic; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; D011164:Porphyrias / Q000201:enzymology* / Q000235:genetics* / Q000503:physiopathology; D051381:Rats; D017208:Rats, Wistar; D015534:Trans-Activators / Q000235:genetics*; D014157:Transcription Factors / Q000378:metabolism; D014162:Transfection; D014407:Tumor Cells, Cultured; D015854:Up-Regulation / Q000502:physiology
D000071161:Forkhead Box Protein O1; D051858:Forkhead Transcription Factors; C467200:Foxo1 protein, mouse; D007328:Insulin; D000071248:Peroxisome Proliferator-Activated Receptor Gamma Coactivator 1-alpha; C485290:Ppargc1a protein, mouse; D015534:Trans-Activators; D014157:Transcription Factors; D006418:Heme; D005934:Glucagon; D000624:5-Aminolevulinate Synthetase; D005947:Glucose