Skip to main page content
Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2012 Jul 6;287(28):23537-48.
doi: 10.1074/jbc.M112.363960. Epub 2012 May 23.

Insulin Resistance and Metabolic Derangements in Obese Mice Are Ameliorated by a Novel Peroxisome Proliferator-Activated Receptor γ-Sparing Thiazolidinedione

Affiliations
Free PMC article

Insulin Resistance and Metabolic Derangements in Obese Mice Are Ameliorated by a Novel Peroxisome Proliferator-Activated Receptor γ-Sparing Thiazolidinedione

Zhouji Chen et al. J Biol Chem. .
Free PMC article

Abstract

Currently approved thiazolidinediones (TZDs) are effective insulin-sensitizing drugs that may have efficacy for treatment of a variety of metabolic and inflammatory diseases, but their use is limited by side effects that are mediated through ectopic activation of the peroxisome proliferator-activated receptor γ (PPARγ). Emerging evidence suggests that the potent anti-diabetic efficacy of TZDs can be separated from the ability to serve as ligands for PPARγ. A novel TZD analog (MSDC-0602) with very low affinity for binding and activation of PPARγ was evaluated for its effects on insulin resistance in obese mice. MSDC-0602 treatment markedly improved several measures of multiorgan insulin sensitivity, adipose tissue inflammation, and hepatic metabolic derangements, including suppressing hepatic lipogenesis and gluconeogenesis. These beneficial effects were mediated at least in part via direct actions on hepatocytes and were preserved in hepatocytes from liver-specific PPARγ(-/-) mice, indicating that PPARγ was not required to suppress these pathways. In conclusion, the beneficial pharmacology exhibited by MSDC-0602 on insulin sensitivity suggests that PPARγ-sparing TZDs are effective for treatment of type 2 diabetes with reduced risk of PPARγ-mediated side effects.

Figures

FIGURE 1.
FIGURE 1.
Chemical structure of MSDC-0602. A, the chemical structures of rosiglitazone, pioglitazone, and MSDC-0602 are shown. B, the graph depicts the binding of the indicated TZDs to recombinant PPARγ protein in a Lantha-Screen TR FRET competitive binding assay. The results of one representative experiment (of three) are shown, and each point represents the average of three samples. C, the graphs represent the results of mammalian one-hybrid assays using Gal4-PPARγ or Gal4-PPARα expression constructs cotransfected into HepG2 cells with a UAS-TK-luciferase reporter. Values are expressed as raw luciferase units (RLU) and represent the average of three independent experiments performed in triplicate. D, the expression of the PPARγ target genes in 3T3-L1 adipocytes 48 h after the induction of differentiation and treatment with 0.1 μm concentrations of the indicated TZDs is shown. *, p < 0.05 versus DMSO control. **, p < 0.05 versus DMSO control and rosiglitazone-treated cells. rosi, rosiglitazone; pio, pioglitazone. E, the affinity of the indicated TZDs for mitochondrial binding is depicted in the graph, and the chemical structure of the cross-linker is shown. The results of one representative experiment (of three) are shown, and each point represents the average of three samples.
FIGURE 2.
FIGURE 2.
TZD treatment improves insulin sensitivity and remedies adipose tissue inflammation in ob/ob mice. A, glucose and insulin tolerance curves for lean, ob/ob (control diet), and ob/ob mice treated with the indicated TZDs for 4 weeks are shown. *, p < 0.05 versus all other groups. rosi, rosiglitazone; pio, pioglitazone. B, representative Western blots using gastrocnemius lysates from mice injected with saline (S) or insulin (I) before sacrifice and the antibodies listed at the left are shown. The table inset represents the normalized and corrected (to total Akt) band intensity for insulin-stimulated Akt phosphorylation for n = 4 per group. C, expression of the indicated genes in epididymal adipose tissue is depicted in the graphs. n = 6 per group. *, p < 0.05 versus lean and TZD-treated mice. **, p < 0.05 versus ob/ob control and lean control mice.
FIGURE 3.
FIGURE 3.
MSDC-0602 treatment improves whole body and tissue insulin sensitivity in DIO mice. Hyperinsulinemic clamp studies performed after 3 weeks of treatment with MSDC-0602 in DIO mice demonstrate a significant improvement in plasma insulin concentration (A), glucose infusion rate (B), tissue glucose uptake (C), and hepatic glucose production (D). n = 11 per group. *, p < 0.05 versus DIO control diet mice. **, p < 0.05 versus clamped DIO control mice and basal values for MSDC-0602-treated mice. AUC, area under the curve. E, representative Western blots using liver lysates from mice injected with insulin (I) before sacrifice and the antibodies listed at the left are shown. The table inset represents the normalized and corrected (to total Akt) band intensity for insulin-stimulated Akt phosphorylation for n = 3 per group. Expression of the indicated genes in liver is depicted in the graphs. n = 8 per group. *, p < 0.05 versus lean and MSDC-0602-treated mice. **, p < 0.05 versus DIO control and lean control mice. AU, absorbance units.
FIGURE 4.
FIGURE 4.
Mitochondrial oxygen consumption is increased and dysregulated lipogenesis in DIO mice is corrected by MSDC-0602 treatment. A, mitochondrial respiration was performed on isolated mitochondria and using succinate-rotenone as a substrate. *, p < 0.05 versus other groups mice. FCCP, carbonylcyanide-p-trifluoromethoxyphenylhydrazone. B, the graph depicts the hepatic expression of genes encoding glycolytic and lipogenic enzymes. n = 8 per group. *p < 0.05 versus lean mice. **p < 0.05 versus DIO and lean mice. Inset, representative Western blots using liver lysates and the antibodies listed at the left are shown. The table represents the normalized and corrected (to actin) band intensity for FAS (n = 6 per group). AU, absorbance units. C, the graph depicts rates of fatty acid synthesis in hepatocytes. *, p < 0.05 versus lean mice. **, p < 0.05 versus DIO and lean mice. D, the graph depicts the hepatic expression of genes encoding enzymes involved in TG esterification. *, p < 0.05 versus lean mice. **, p < 0.05 versus DIO and lean mice. E, the graph depicts rates of triglyceride synthesis in hepatocytes. *, p < 0.05 versus lean mice. **, p < 0.05 versus DIO and lean mice.
FIGURE 5.
FIGURE 5.
MSDC-0602 does not induce hepatic expression of PPARγ target genes. A, the graphs depict the hepatic expression of PPARγ target genes in lean or DIO mice treated as indicated. n = 8 per group. *, p < 0.05 versus lean mice. B, the graphs depict the hepatic expression of PPARγ target genes in lean or ob/ob mice treated with TZDs. n = 6 per group. *, p < 0.05 versus lean mice. **, p < 0.05 versus lean, ob/ob control, and ob/ob MSDC-0602-treated mice. AU, absorbance units; rosi, rosiglitazone; pio, pioglitazone.
FIGURE 6.
FIGURE 6.
MSDC-0602 suppresses gluconeogenesis and lipogenesis in primary hepatocytes independent of PPARγ. A, the graphs depict the expression of the indicated genes in mouse hepatocytes from WT or LS-PPARγ−/− DIO mice treated in vitro with vehicle (DMSO), rosiglitazone (1 μm), or MSDC-0602 (1 μm) for 18 h. *, p < 0.05 versus DMSO control hepatocytes. Representative Western blots using lysates from mouse hepatocytes from WT or LS-PPARγ−/− DIO mice treated in vitro with vehicle (DMSO), rosiglitazone (1 μm), or MSDC-0602 (1 μm) for 18 h and the antibodies listed at the left are shown. The values below each image represent the normalized and corrected (to actin) band intensity for the blot and group above (n = 4 per group). B, the graph depicts rates of glucose release by hepatocytes isolated from DIO mice treated for 24 h with vehicle (DMSO) or MSDC-0602 (5 μm). *, p < 0.05 versus DMSO control hepatocytes. C, the graphs depict the expression of PPARγ target genes in hepatocytes from WT or LS-PPARγ−/− DIO mice treated in vitro with vehicle (DMSO), rosiglitazone (1 μm), or MSDC-0602 (1 μm) for 18 h. *, p < 0.05 versus DMSO control hepatocytes. AU, absorbance units.

Similar articles

See all similar articles

Cited by 39 articles

See all "Cited by" articles

Publication types

MeSH terms

Feedback