PPARgamma activation attenuates T-lymphocyte-dependent inflammation of adipose tissue and development of insulin resistance in obese mice.
BACKGROUND
Inflammation of adipose tissue (AT) has been recently accepted as a first step towards obesity-mediated insulin resistance. We could previously show that mice fed with high fat diet (HFD) develop systemic insulin resistance (IR) and glucose intolerance (GI) associated with CD4-positive T-lymphocyte infiltration into visceral AT. These T-lymphocytes, when enriched in AT, participate in the development of fat tissue inflammation and subsequent recruitment of proinflammatory macrophages. The aim of this work was to elucidate the action of the insulin sensitizing PPARgamma on T-lymphocyte infiltration during development of IR, and comparison of the PPARgamma-mediated anti-inflammatory effects of rosiglitazone and telmisartan in diet-induced obesity model (DIO-model) in mice.


METHODS
In order to investigate the molecular mechanisms underlying early development of systemic insulin resistance and glucose intolerance male C57BL/6J mice were fed with high fat diet (HFD) for 10-weeks in parallel to the pharmacological intervention with rosiglitazone, telmisartan, or vehicle.


RESULTS
Both rosiglitazone and telmisartan were able to reduce T-lymphocyte infiltration into AT analyzed by quantitative analysis of the T-cell marker CD3gamma and the chemokine SDF1alpha. Subsequently, both PPARgamma agonists were able to attenuate macrophage infiltration into AT, measured by the reduction of MCP1 and F4/80 expression. In parallel to the reduction of AT-inflammation, ligand-activated PPARgamma improved diet-induced IR and GI.


CONCLUSIONS
Together the present study demonstrates a close connection between PPARgamma-mediated anti-inflammation in AT and systemic improvement of glucose metabolism identifying T-lymphocytes as one cellular mediator of PPARgamma´s action.
Center for Cardiovascular Research, Institute of Pharmacology Charité-Universitätsmedizin Berlin, Germany.
Anna
A
Foryst-Ludwig
Martin
M
Hartge
Markus
M
Clemenz
Christiane
C
Sprang
Katharina
K
Hess
Nikolaus
N
Marx
Thomas
T
Unger
Ulrich
U
Kintscher
D050153:Abdominal Fat / Q000187:drug effects* / Q000276:immunology / Q000378:metabolism; D000818:Animals; D000893:Anti-Inflammatory Agents / Q000494:pharmacology*; D000943:Antigens, Differentiation / Q000378:metabolism; D001562:Benzimidazoles / Q000494:pharmacology*; D001565:Benzoates / Q000494:pharmacology*; D017252:CD3 Complex / Q000378:metabolism; D054377:Chemokine CXCL12 / Q000378:metabolism; D002633:Chemotaxis / Q000187:drug effects; D004041:Dietary Fats; D004195:Disease Models, Animal; D007249:Inflammation / Q000276:immunology / Q000378:metabolism / Q000517:prevention & control*; D007333:Insulin Resistance; D008213:Lymphocyte Activation / Q000187:drug effects; D008264:Macrophages / Q000187:drug effects / Q000276:immunology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009765:Obesity / Q000188:drug therapy* / Q000276:immunology / Q000378:metabolism; D047495:PPAR gamma / Q000819:agonists* / Q000378:metabolism; D000077154:Rosiglitazone; D013601:T-Lymphocytes / Q000187:drug effects* / Q000276:immunology; D000077333:Telmisartan; D045162:Thiazolidinediones / Q000494:pharmacology*; D013997:Time Factors
D000893:Anti-Inflammatory Agents; D000943:Antigens, Differentiation; D001562:Benzimidazoles; D001565:Benzoates; D017252:CD3 Complex; C452842:CD3 antigen, gamma chain; D054377:Chemokine CXCL12; C515256:Cxcl12 protein, mouse; D004041:Dietary Fats; D047495:PPAR gamma; D045162:Thiazolidinediones; C036763:monocyte-macrophage differentiation antigen; D000077154:Rosiglitazone; D000077333:Telmisartan