Thyroid Hormone at Near Physiologic Concentrations Acutely Increases Oxygen Consumption and Extracellular Acidification in LH86 Hepatoma Cells.
Thyroid hormone (T3) has been known to regulate the basal metabolic rate for more than a century, but mechanistic understanding is lacking both at the level of the intact organism and in terms of how T3 alters energy expenditure in individual tissues. The current studies investigate the question of which metabolically relevant genes respond acutely as T3 concentrations increase through the physiologic range in liver cells. Because this has been technically unfeasible historically, we developed a modified protocol for extracellular flux analysis using a 96-well Extracellular Flux Analyzer (Seahorse Bioscience). Using a modified extracellular flux protocol and LH86 human hepatoma cells, we established an experimental system where small but significant changes in O2 consumption could be reproducibly quantified as hypothyroid cells were exposed to near-physiologic final concentrations of T3 approximately 2 orders of magnitude lower than most studies (0.04 nM free T3), in only 6-7 hours. Taking advantage of the nondestructive nature of 96-well Extracellular Flux Analyzer measurements, the acute, direct, transcriptional changes that occur were measured in the exact same cells demonstrating increased O2 consumption. An unbiased, genome-wide microarray analysis identified potential candidate genes related to fatty acid oxidation, angiogenesis, nucleotide metabolism, immune signaling, mitochondrial respiration, and cell proliferation. The identified transcriptome is likely enriched in the genes most important for mediating the energetic effects of T3 in hepatoma cells.
Division of Endocrinology and Metabolism (E.A.M., S.J., B.W.K.), Rush University Medical Center, Chicago, Illinois 60612; University of South Florida Morsani College of Medicine (B.T.M.), Tampa, Florida 33612; and Institute of Biomedical Science (C.B.U.), University of São Paulo, São Paulo SP 05508-000, Brazil.
Elizabeth A
EA
McAninch
Division of Endocrinology and Metabolism (E.A.M., S.J., B.W.K.), Rush University Medical Center, Chicago, Illinois 60612; University of South Florida Morsani College of Medicine (B.T.M.), Tampa, Florida 33612; and Institute of Biomedical Science (C.B.U.), University of São Paulo, São Paulo SP 05508-000, Brazil.
Bradford T
BT
Miller
Division of Endocrinology and Metabolism (E.A.M., S.J., B.W.K.), Rush University Medical Center, Chicago, Illinois 60612; University of South Florida Morsani College of Medicine (B.T.M.), Tampa, Florida 33612; and Institute of Biomedical Science (C.B.U.), University of São Paulo, São Paulo SP 05508-000, Brazil.
Cintia B
CB
Ueta
Division of Endocrinology and Metabolism (E.A.M., S.J., B.W.K.), Rush University Medical Center, Chicago, Illinois 60612; University of South Florida Morsani College of Medicine (B.T.M.), Tampa, Florida 33612; and Institute of Biomedical Science (C.B.U.), University of São Paulo, São Paulo SP 05508-000, Brazil.
Sungro
S
Jo
Division of Endocrinology and Metabolism (E.A.M., S.J., B.W.K.), Rush University Medical Center, Chicago, Illinois 60612; University of South Florida Morsani College of Medicine (B.T.M.), Tampa, Florida 33612; and Institute of Biomedical Science (C.B.U.), University of São Paulo, São Paulo SP 05508-000, Brazil.
Brian W
BW
Kim
D006528:Carcinoma, Hepatocellular / Q000378:metabolism; D045744:Cell Line, Tumor; D006706:Homeostasis / Q000187:drug effects; D006801:Humans; D007037:Hypothyroidism / Q000378:metabolism; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D008113:Liver Neoplasms / Q000378:metabolism; D008928:Mitochondria / Q000187:drug effects* / Q000378:metabolism; D010084:Oxidation-Reduction; D010101:Oxygen Consumption / Q000187:drug effects*; D014284:Triiodothyronine / Q000494:pharmacology*
D014284:Triiodothyronine