| First Author | Serrano-Marco L | Year | 2012 |
| Journal | Diabetologia | Volume | 55 |
| Issue | 3 | Pages | 743-51 |
| PubMed ID | 22179221 | Mgi Jnum | J:181729 |
| Mgi Id | MGI:5313781 | Doi | 10.1007/s00125-011-2401-4 |
| Citation | Serrano-Marco L, et al. (2012) The peroxisome proliferator-activated receptor (PPAR) beta/delta agonist GW501516 inhibits IL-6-induced signal transducer and activator of transcription 3 (STAT3) activation and insulin resistance in human liver cells. Diabetologia 55(3):743-51 |
| abstractText | AIM/HYPOTHESIS: IL-6 induces insulin resistance by activating signal transducer and activator of transcription 3 (STAT3) and upregulating the transcription of its target gene SOCS3. Here we examined whether the peroxisome proliferator-activated receptor (PPAR)beta/delta agonist GW501516 prevented activation of the IL-6-STAT3-suppressor of cytokine signalling 3 (SOCS3) pathway and insulin resistance in human hepatic HepG2 cells. METHODS: Studies were conducted with human HepG2 cells and livers from mice null for Pparbeta/delta (also known as Ppard) and wild-type mice. RESULTS: GW501516 prevented IL-6-dependent reduction in insulin-stimulated v-akt murine thymoma viral oncogene homologue 1 (AKT) phosphorylation and in IRS-1 and IRS-2 protein levels. In addition, treatment with this drug abolished IL-6-induced STAT3 phosphorylation of Tyr(705) and Ser(727) and prevented the increase in SOCS3 caused by this cytokine. Moreover, GW501516 prevented IL-6-dependent induction of extracellular-related kinase 1/2 (ERK1/2), a serine-threonine protein kinase involved in serine STAT3 phosphorylation; the livers of Pparbeta/delta-null mice showed increased Tyr(705)- and Ser(727)-STAT3 as well as phospho-ERK1/2 levels. Furthermore, drug treatment prevented the IL-6-dependent reduction in phosphorylated AMP-activated protein kinase (AMPK), a kinase reported to inhibit STAT3 phosphorylation on Tyr(705). In agreement with the recovery in phospho-AMPK levels observed following GW501516 treatment, this drug increased the AMP/ATP ratio and decreased the ATP/ADP ratio. CONCLUSIONS/INTERPRETATION: Overall, our findings show that the PPARbeta/delta activator GW501516 prevents IL-6-induced STAT3 activation by inhibiting ERK1/2 phosphorylation and preventing the reduction in phospho-AMPK levels. These effects of GW501516 may contribute to the prevention of cytokine-induced insulin resistance in hepatic cells. |
