Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2013;8(2):e55963.
doi: 10.1371/journal.pone.0055963. Epub 2013 Feb 5.

Chronic endocannabinoid system stimulation induces muscle macrophage and lipid accumulation in type 2 diabetic mice independently of metabolic endotoxaemia

Lucie Geurts  1 , Giulio G Muccioli, Nathalie M Delzenne, Patrice D Cani
Affiliations

Chronic endocannabinoid system stimulation induces muscle macrophage and lipid accumulation in type 2 diabetic mice independently of metabolic endotoxaemia

Lucie Geurts et al. PLoS One. 2013.

Abstract

Aims: Obesity and type 2 diabetes are characterised by low-grade inflammation, metabolic endotoxaemia (i.e., increased plasma lipopolysaccharides [LPS] levels) and altered endocannabinoid (eCB)-system tone. The aim of this study was to decipher the specific role of eCB-system stimulation or metabolic endotoxaemia in the onset of glucose intolerance, metabolic inflammation and altered lipid metabolism.

Methods: Mice were treated with either a cannabinoid (CB) receptor agonist (HU210) or low-dose LPS using subcutaneous mini-pumps for 6 weeks. After 3 weeks of the treatment under control (CT) diet, one-half of each group of mice were challenged with a high fat (HF) diet for the following 3-week period.

Results: Under basal conditions (control diet), chronic CB receptor agonist treatment (i.e., 6 weeks) induced glucose intolerance, stimulated metabolic endotoxaemia, and increased macrophage infiltration (CD11c and F4/80 expression) in the muscles; this phenomenon was associated with an altered lipid metabolism (increased PGC-1α expression and decreased CPT-1b expression) in this tissue. Chronic LPS treatment tended to increase the body weight and fat mass, with minor effects on the other metabolic parameters. Challenging mice with an HF diet following pre-treatment with the CB agonist exacerbated the HF diet-induced glucose intolerance, the muscle macrophage infiltration and the muscle's lipid content without affecting the body weight or the fat mass.

Conclusion: Chronic CB receptor stimulation under basal conditions induces glucose intolerance, stimulates metabolic inflammation and alters lipid metabolism in the muscles. These effects worsen following the concomitant ingestion of an HF diet. Here, we highlight the central roles played by the eCB system and LPS in the pathophysiology of several hallmarks of obesity and type 2 diabetes.

PubMed Disclaimer

Conflict of interest statement

Competing Interests: The authors have declared that no competing interests exist.

Figures

Figure 1
Figure 1. Cannabinoid receptor expression after chronic CB receptor agonist treatment or LPS treatment.
(A) CB1 mRNA levels and (B) CB2 mRNA levels in the tibialis anterior muscle. All results are the means±SEM for 7–9 mice per group from the HU-treated group (HU) and the LPS-treated group (LPS) compared with the results of the control group (CT). The data with different superscripted letters are significantly different based on the one-way ANOVA followed by the Bonferroni post hoc test.
Figure 2
Figure 2. Oral glucose tolerance test and insulin levels after chronic CB receptor agonist treatment or LPS treatment.
(A) Plasma glucose profile subsequent to a 2 g/kg glucose oral challenge in freely mobile mice. Two-way ANOVA followed by the Bonferroni post hoc analysis revealed the time (p<0.0001), treatment (p = 0.195) and interaction (p = 0.046) effects. * indicates a significant difference (p<0.05) versus CT, as determined by a two-way ANOVA followed by the Bonferroni post hoc test. (B) Plasma insulin levels at 30 min before glucose loading and 15 min after glucose loading. All results are expressed as the means±SEM for 7–9 mice per group from the HU-treated group (HU) and the LPS-treated group (LPS) compared with the plasma insulin levels of the control group (CT).
Figure 3
Figure 3. Plasma LPS levels and inflammation markers after chronic CB receptor agonist treatment or LPS treatment.
(A) Plasma LPS levels; (B) F4/80 mRNA levels in the tibialis anterior muscle; (C) CD11c mRNA levels in the tibialis anterior muscle. All results are expressed as the means±SEM for 7–9 mice per group from the HU-treated group (HU) and the LPS-treated group (LPS) compared with the levels in the control group (CT). The data with different superscripted letters are significantly different based on a one-way ANOVA followed by the Bonferroni post hoc test.
None
Lipid metabolism marker mRNA levels after chronic CB receptor agonist treatment or LPS treatment.
(A) CPT-1b mRNA levels; (B) PGC-1α mRNA levels in the tibialis anterior muscle. All results are expressed as the means±SEM for 7–9 mice per group from the HU-treated group (HU) and the LPS-treated group (LPS) compared with the levels in the control group (CT). The data with different superscripted letters are significantly different based on a one-way ANOVA followed by the Bonferroni post hoc test.
Figure 5
Figure 5. Oral glucose tolerance tests and insulin levels under the HF diet.
(A) Plasma glucose profile following an oral challenge with 2 g/kg glucose in freely mobile mice. A two-way ANOVA followed by the Bonferroni post hoc analysis revealed the time (p<0.0001), treatment (p<0.0001) and interaction (p<0.0001) effects. * indicates a significant difference (p<0.05) versus CT, and • indicates a significant difference (p<0.05) versus HF as determined by a two-way ANOVA followed by the Bonferroni post hoc test. (B) Glucose areas under the curves (AUCs), measured between 0 and 120 min after glucose loading. The data with different superscripted letters are significantly different based on a one-way ANOVA followed by the Bonferroni post hoc test. (C) Plasma insulin levels at 30 min before glucose loading and 15 min after glucose loading. * indicates a significant difference (p<0.05) versus the CT time (−30 min), as determined by a one-way ANOVA test. • indicates a significant difference (p<0.05) versus the CT time (15 min) as determined by a one-way ANOVA. (D) Insulin areas under the curves (AUCs) measured between the basal time and 15 minutes after glucose loading. The data with different superscripted letters are significantly different based on a one-way ANOVA followed by the Bonferroni post hoc test. All results are expressed as the means±SEM for 7–9 mice per group from the HF diet-treated group (HF), the HF- and HU-treated group (HF-HU) and the HF- and LPS-treated group (HF-LPS) or the control group (CT).
Figure 6
Figure 6. Plasma LPS and inflammation markers under HF diet.
(A) Plasma LPS levels; (B) F4/80 mRNA levels; (C) CD11c mRNA levels in the tibialis anterior muscle. All results are presented as the means±SEM for 7–9 mice per group from the HF diet-treated group (HF), the HF-and HU-treated group (HF-HU) and the HF-and LPS-treated group (HF-LPS) compared with the levels in the control group (CT). The data with different superscripted letters are significantly different based on a one-way ANOVA followed by the Bonferroni post hoc test.
Figure 7
Figure 7. Muscle lipid metabolism markers under the HF diet.
(A) GLUT-4 mRNA levels; (B) LPL mRNA levels; (C) CPT-1b mRNA levels; (D) PGC-1α mRNA levels in the tibialis anterior muscle; (E) Muscle lipid content (relative unit); and (F) Oil Red staining performed on frozen sections of the tibialis anterior muscles from the HF diet-treated group (HF), the HF- and HU-treated group (HF-HU) and the HF- and LPS-treated group (HF-LPS) compared with the levels in the control group (CT). All results are expressed as the means±SEM for 7–9 mice per group from the HF diet-treated group (HF), the HF- and HU-treated group (HF-HU) and the HF- and LPS-treated group (HF-LPS) compared with the levels in the control group (CT). Scale bar: 50 µm. The data with different superscripted letters are significantly different based on a one-way ANOVA followed by the Bonferroni post hoc test.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Olefsky JM, Glass CK (2010) Macrophages, inflammation, and insulin resistance. AnnuRevPhysiol 72: 219–246. - PubMed
    1. Cani PD, Amar J, Iglesias MA, Poggi M, Knauf C, et al. (2007) Metabolic endotoxemia initiates obesity and insulin resistance. Diabetes 56: 1761–1772. - PubMed
    1. Bluher M, Engeli S, Kloting N, Berndt J, Fasshauer M, et al. (2006) Dysregulation of the peripheral and adipose tissue endocannabinoid system in human abdominal obesity. Diabetes 55: 3053–3060. - PMC - PubMed
    1. Engeli S, Bohnke J, Feldpausch M, Gorzelniak K, Janke J, et al. (2005) Activation of the peripheral endocannabinoid system in human obesity. Diabetes 54: 2838–2843. - PMC - PubMed
    1. Lambert DM, Muccioli GG (2007) Endocannabinoids and related N-acylethanolamines in the control of appetite and energy metabolism: emergence of new molecular players. CurrOpinClinNutrMetab Care 10: 735–744. - PubMed

Publication types

Grants and funding

Sources of funding: SFD (Société Francophone du Diabète); FSR (Fonds Spéciaux de Recherche, UCL (Université catholique de Louvain); FRSM (Fonds de la Recherche Scientifique Medicale). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
  NODES
twitter 2