Adiponectin upregulates monocytic activin A but systemic levels are not altered in obesity or type 2 diabetes.
Adiponectin is an adipocyte-derived protein with atheroprotective and immunoregulatory function. Adiponectin and activin A reduce foam cell formation and adiponectin activates the p38 MAPK pathway that is well described to induce activin A. Therefore, it was analyzed whether adiponectin alters activin A in primary human monocytes. Adiponectin dose- and time-dependently induced activin A in the supernatant, and the maximal amount was observed after 12h of incubation. Adiponectin-stimulated release of activin A was blocked by a p38 MAPK inhibitor. Metformin and pioglitazone are drugs frequently used to treat diabetic patients and metformin slightly reduced monocytic activin A release whereas pioglitazone had no effect. Type 2 diabetes is associated with elevated inflammatory systemic cytokines but activin A serum levels were similar in slim probands, overweight controls and type 2 diabetic patients. Furthermore, activin A did not correlate to systemic adiponectin, body mass index, waist to hip ratio or C-reactive protein. These findings indicate that adiponectin upregulates monocytic activin A release via the p38 MAPK pathway, and this may in part explain the immunoregulatory and antiatherosclerotic effects of this adipokine.
Weigert
Johanna
J
Department of Internal Medicine I, Regensburg University Hospital, Franz Josef Strauss Allee 11, 93042 Regensburg, Germany.
Neumeier
Markus
M
Wanninger
Josef
J
Schober
Franziska
F
Sporrer
Daniela
D
Weber
Markus
M
Schramm
Andrea
A
Wurm
Sylvia
S
Stögbauer
Fabian
F
Filarsky
Michael
M
Schäffler
Andreas
A
Aslanidis
Charalampos
C
Schölmerich
Jürgen
J
Buechler
Christa
C
D028341:Activins / Q000378:metabolism*; D052242:Adiponectin / Q000494:pharmacology*; D000368:Aged; D002478:Cells, Cultured; D003924:Diabetes Mellitus, Type 2 / Q000378:metabolism*; D006801:Humans; D007004:Hypoglycemic Agents / Q000494:pharmacology; D020935:MAP Kinase Signaling System / Q000502:physiology; D008297:Male; D008687:Metformin / Q000494:pharmacology; D008875:Middle Aged; D009000:Monocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D009765:Obesity / Q000378:metabolism*; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism
D052242:Adiponectin; D007004:Hypoglycemic Agents; C422405:activin A; D028341:Activins; D008687:Metformin; D048051:p38 Mitogen-Activated Protein Kinases