Vigueira 2017 Exp Physiol
Vigueira PA, McCommis KS, Hodges WT, Schweitzer GG, Cole SL, Oonthonpan L, Taylor EB, McDonald WG, Kletzien RF, Colca JR, Finck BN (2017) The beneficial metabolic effects of insulin sensitizers are not attenuated by mitochondrial pyruvate carrier 2 hypomorphism. Exp Physiol 102:985-99. |
Vigueira PA, McCommis KS, Hodges WT, Schweitzer GG, Cole SL, Oonthonpan L, Taylor EB, McDonald WG, Kletzien RF, Colca JR, Finck BN (2017) Exp Physiol
Abstract: What is the central question of this study? The antidiabetic effects of thiazolidinedione (TZD) drugs may be mediated in part by a molecular interaction with the constituent proteins of the mitochondrial pyruvate carrier complex (MPC1 and MPC2). We examined the ability of a mutant mouse strain expressing an N-terminal truncation of MPC2 (Mpc2Ξ16 mice) to respond to TZD treatment. What is the main finding and its importance? The response of Mpc2Ξ16 mice to TZD treatment was not significantly different from that of wild-type C57BL6/J control animals, suggesting that the 16 N-terminal amino acids of MPC2 are dispensable for the effects of TZD treatment. Rosiglitazone and pioglitazone are thiazolidinedione (TZD) compounds that have been used clinically as insulin-sensitizing drugs and are generally believed to mediate their effects via activation of the peroxisome proliferator-activated receptor Ξ³ (PPARΞ³). Recent work has shown that it is possible to synthesize TZD compounds with potent insulin-sensitizing effects and markedly diminished affinity for PPARΞ³. Both clinically used TZDs and investigational PPARΞ³-sparing TZDs, such as MSDC-0602, interact with the mitochondrial pyruvate carrier (MPC) and inhibit its activity. The MPC complex is composed of two proteins, MPC1 and MPC2. Herein, we used mice expressing a hypomorphic MPC2 protein missing 16 amino acids in the N-terminus (Mpc2Ξ16 mice) to determine the effects of these residues in mediating the insulin-sensitizing effects of TZDs in diet-induced obese mice. We found that both pioglitazone and MSDC-0602 elicited their beneficial metabolic effects, including improvement in glucose tolerance, attenuation of hepatic steatosis, reduction of adipose tissue inflammation and stimulation of adipocyte browning, in both wild-type and Mpc2Ξ16 mice after high-fat diet feeding. In addition, truncation of MPC2 failed to attenuate the interaction between TZDs and the MPC in a bioluminescence resonance energy transfer-based assay or to affect the suppression of pyruvate-stimulated respiration in cells. Collectively, these data suggest that the interaction between TZDs and MPC2 is not affected by loss of the N-terminal 16 amino acids nor are these residues required for the insulin-sensitizing effects of these compounds.
Β© 2017 The Authors. Experimental Physiology Β© 2017 The Physiological Society. β’ Keywords: Diabetes, Insulin resistance, Mitochondria β’ Bioblast editor: Kandolf G β’ O2k-Network Lab: US MO St Louis Finck B
Labels: MiParea: Respiration, nDNA;cell genetics, Genetic knockout;overexpression, Pharmacology;toxicology
Pathology: Obesity
Organism: Human Tissue;cell: Kidney, HEK Preparation: Permeabilized cells
Coupling state: LEAK, OXPHOS
Pathway: N
HRR: Oxygraph-2k
2017-08