TY - JOUR
T1 - Spare mitochondrial respiratory capacity permits human adipocytes to maintain ATP homeostasis under hypoglycemic conditions
AU - Keuper, Michaela
AU - Jastroch, Martin
AU - Yi, Chun-Xia
AU - Fischer-Posovszky, Pamela
AU - Wabitsch, Martin
AU - Tschöp, Matthias H.
AU - Hofmann, Susanna M.
PY - 2014
Y1 - 2014
N2 - Mitochondrial dysfunction in white adipose tissue plays a key role in the pathogenesis of type 2 diabetes. Emerging evidence specifically suggests that altered oxidative phosphorylation in adipocytes may have a relevant effect on systemic glucose homeostasis, requiring understanding of adipocyte bioenergetics. We analyzed energetic flux of an intact human adipocyte cell model by plate-based respirometry and extracellular acidification. During differentiation, we discovered that glycolytic ATP production was increasingly replaced by mitochondrial oxidative metabolism (from 20 to 60%). This observation was corroborated by simultaneous up-regulation of canonical mitochondrial gene programs, such as peroxisome proliferator-activated receptor coactivator (PGC1; 150-fold) and cytochrome c-1 (CytC; 3-fold). Mimicking diabetic phenotypes by exposure to various glucose levels (0, 5, and 25 mM) resulted in immediate adjustments of glycolytic and mitochondrial activity that aimed to maintain intracellular ATP. We conclude that ATP deficits by mitochondrial failure are compensated by glycolytic ATP production, resulting in inefficient conversion of glucose to cellular ATP. Metabolic inefficiency may enhance glucose uptake, therefore improving systemic glucose homeostasis. Notably, mature adipocytes developed a high spare respiratory capacity (increased by 6-fold) permitting rapid adaptation to metabolic changes. Spare respiratory capacity may also allow additional metabolic scope for energy dissipation, potentially offering new therapeutic targets for the treatment of metabolic disease.Keuper, M., Jastroch, M., Yi, C.-X., Fischer-Posovszky, P., Wabitsch, M., Tschop, M. H., Hofmann, S. M. Spare mitochondrial respiratory capacity permits human adipocytes to maintain ATP homeostasis under hypoglycemic conditions
AB - Mitochondrial dysfunction in white adipose tissue plays a key role in the pathogenesis of type 2 diabetes. Emerging evidence specifically suggests that altered oxidative phosphorylation in adipocytes may have a relevant effect on systemic glucose homeostasis, requiring understanding of adipocyte bioenergetics. We analyzed energetic flux of an intact human adipocyte cell model by plate-based respirometry and extracellular acidification. During differentiation, we discovered that glycolytic ATP production was increasingly replaced by mitochondrial oxidative metabolism (from 20 to 60%). This observation was corroborated by simultaneous up-regulation of canonical mitochondrial gene programs, such as peroxisome proliferator-activated receptor coactivator (PGC1; 150-fold) and cytochrome c-1 (CytC; 3-fold). Mimicking diabetic phenotypes by exposure to various glucose levels (0, 5, and 25 mM) resulted in immediate adjustments of glycolytic and mitochondrial activity that aimed to maintain intracellular ATP. We conclude that ATP deficits by mitochondrial failure are compensated by glycolytic ATP production, resulting in inefficient conversion of glucose to cellular ATP. Metabolic inefficiency may enhance glucose uptake, therefore improving systemic glucose homeostasis. Notably, mature adipocytes developed a high spare respiratory capacity (increased by 6-fold) permitting rapid adaptation to metabolic changes. Spare respiratory capacity may also allow additional metabolic scope for energy dissipation, potentially offering new therapeutic targets for the treatment of metabolic disease.Keuper, M., Jastroch, M., Yi, C.-X., Fischer-Posovszky, P., Wabitsch, M., Tschop, M. H., Hofmann, S. M. Spare mitochondrial respiratory capacity permits human adipocytes to maintain ATP homeostasis under hypoglycemic conditions
U2 - https://doi.org/10.1096/fj.13-238725
DO - https://doi.org/10.1096/fj.13-238725
M3 - Article
C2 - 24200885
SN - 0892-6638
VL - 28
SP - 761
EP - 770
JO - FASEB Journal
JF - FASEB Journal
IS - 2
ER -