Possible involvement of pertussis toxin-sensitive GTP-binding protein(s) in c-fos expression during differentiation of 3T3-L1 fibroblasts to adipocytes

Uehara, Takashi; Chihara, Tomihiko; Tokumitsu, Yukiko; Nomura, Yasuyuki

doi:10.1016/0167-4781(91)90151-b

Cited by 11 publications

(9 citation statements)

References 26 publications

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“…Insulin signaling through the Ras/ERK1/2 and PI3K/Akt pathways is considered to play a critical role in the process of adipocyte differentiation [19,20]. Therefore, we examined the effects of honokiol on these insulin signaling pathways in 3T3-L1 preadipocytes.…”

Section: Honokiol Regulates Insulin Signaling In 3t3-l1 Preadipocytesmentioning

confidence: 99%

Honokiol enhances adipocyte differentiation by potentiating insulin signaling in 3T3-L1 preadipocytes

et al. 2011

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Adipose tissue plays an essential role in energy homeostasis as a metabolic and endocrine organ. Accordingly, adipocytes are emerging as a major drug target for obesity and obesity-mediated metabolic syndrome. Dysfunction of enlarged adipocytes in obesity is involved in obesity-mediated metabolic syndrome. Adipocytokines, such as adiponectin released from small adipocytes, are able to prevent these disorders. In this study, we found that honokiol, an ingredient of Magnolia officinalis used in traditional Chinese and Japanese medicines, enhanced adipocyte differentiation in 3T3-L1 preadipocytes. Oil Red O staining showed that treatment with honokiol in the presence of insulin dose-dependently increased lipid accumulation in 3T3-L1 preadipoyctes although its activity was weak compared with rosiglitazone. During adipocyte differentiation, the expression of peroxisome proliferator-activated receptor γ2 (PPARγ2) mRNA and PPARγ target genes such as adipocyte protein 2 (aP2), adiponectin, and GLUT4 was induced by treatment with 10 μM honokiol. However, honokiol failed to show direct binding to the PPARγ ligand-binding domain in vitro. In preadipocytes, treatment with honokiol in the presence of insulin increased the phosphorylation of extracellular signal-regulated kinase (ERK) 1/2 protein and Akt protein, early insulin signaling pathways related to adipocyte differentiation, compared with insulin-only treatment. Taken together, our results suggest that honokiol promotes adipocyte differentiation through increased expression of PPARγ2 mRNA and potentiation of insulin signaling pathways such as the Ras/ERK1/2 and phosphoinositide-3-kinase (PI3K)/Akt signaling pathways.

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Section: Honokiol Regulates Insulin Signaling In 3t3-l1 Preadipocytesmentioning

confidence: 99%

Honokiol enhances adipocyte differentiation by potentiating insulin signaling in 3T3-L1 preadipocytes

et al. 2011

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“…Insulin is generally considered to play a crucial role in the process of adipogenesis (Uehara et al, 1991(Uehara et al, , 1994. To determine whether H-89 modulates insulin signaling, we examined the effect of H-89 on both pathways of Ras/ERK1/ 2 and PI3K/Akt, which are downstream signaling of insulin.…”

Section: Effects Of H-89 On Insulin Signaling In 3t3-l1 Cellsmentioning

confidence: 99%

“…It has been reported that insulin is a key factor in the process of differentiation of 3T3-L1 cells (Smith et al, 1988;Uehara et al, 1991Uehara et al, , 1994. The insulin receptor, which is a tyrosine kinase, phosphorylates the insulin receptor substrate (IRS) proteins and Shc, resulting in the activation of Ras/extracellular signal-regulated Life Sciences 80 (2007) 476 -483 www.elsevier.com/locate/lifescie kinase (ERK) 1/2 pathway (Taha and Klip, 1999).…”

Section: Introductionmentioning

confidence: 98%

H-89 potentiates adipogenesis in 3T3-L1 cells by activating insulin signaling independently of protein kinase A

et al. 2007

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“…cAMP accumulation was measured by radioimmunoassay as described previously [22], to plasma membrane fractions Isolated adipocytes were incubated with various agents. The cells were immediately separated from the medium by centrifugation.…”

Section: Measurement Of Camp Accumulationmentioning

confidence: 99%

Suppression of insulin‐stimulated phosphatidylinositol 3‐kinase activity by the β₃‐adrenoceptor agonist CL316243 in rat adipocytes

1997

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Insulin increased 2-deoxyglucose (2-DG) uptake via the translocation of glucose transporter (GLUT) 4 to the plasma membrane fraction in rat adipocytes. The stimulatory actions of insulin were accompanied by both an increase in the immunoreactive p85 subunit of phosphatidylinositol (PI) 3-kinase in the plasma membrane fractions and PI 3-kinase activation by tyrosine phosphorylation of the p85 subunit. The ß 3 -adrenoceptor agonist CL316243 (CL) suppressed all the insulin actions in adenosine deaminase (ADA)-treated cells, but was without effect in non-ADA-treated cells. The inhibitory effects of CL on GLUT 4 translocation and PI 3-kinase activation were abolished by the addition of N 6 -phenylisopropyl adenosine. Cholera toxin treatment, which markedly increased intracellular cAMP levels, suppressed increases in the levels of GLUT 4 and PI 3-kinase in the plasma membrane fractions in response to insulin. In addition, dibutyryl (Bt 2 ) cAMP also impaired the activation of PI 3-kinase by insulin. These results indicated that CL suppressed insulin-stimulated glucose transport under conditions where cAMP levels were markedly increased (~ 12-fold). The inhibitory actions of PI 3-kinase activation by insulin were exerted even when cAMP, 8-bromo-cAMP, or Bt2 cAMP was added to immunoprecipitates of the p85 subunit of PI 3-kinase, after treating the cells with insulin. These results suggest that CL suppressed insulin-stimulated PI 3-kinase activity via a cAMPdependent mechanism, at least in part, direct cAMP action in ADA-treated adipocytes, by which PI 3-kinase activation was inhibited, resulting in the decrease in GLUT 4 translocation and subsequent 2-DG uptake in response to insulin.

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Possible involvement of pertussis toxin-sensitive GTP-binding protein(s) in c-fos expression during differentiation of 3T3-L1 fibroblasts to adipocytes

Cited by 11 publications

References 26 publications

Honokiol enhances adipocyte differentiation by potentiating insulin signaling in 3T3-L1 preadipocytes

Honokiol enhances adipocyte differentiation by potentiating insulin signaling in 3T3-L1 preadipocytes

H-89 potentiates adipogenesis in 3T3-L1 cells by activating insulin signaling independently of protein kinase A

Suppression of insulin‐stimulated phosphatidylinositol 3‐kinase activity by the β₃‐adrenoceptor agonist CL316243 in rat adipocytes

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Possible involvement of pertussis toxin-sensitive GTP-binding protein(s) in c-fos expression during differentiation of 3T3-L1 fibroblasts to adipocytes

Cited by 11 publications

References 26 publications

Honokiol enhances adipocyte differentiation by potentiating insulin signaling in 3T3-L1 preadipocytes

Honokiol enhances adipocyte differentiation by potentiating insulin signaling in 3T3-L1 preadipocytes

H-89 potentiates adipogenesis in 3T3-L1 cells by activating insulin signaling independently of protein kinase A

Suppression of insulin‐stimulated phosphatidylinositol 3‐kinase activity by the β3‐adrenoceptor agonist CL316243 in rat adipocytes

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Suppression of insulin‐stimulated phosphatidylinositol 3‐kinase activity by the β₃‐adrenoceptor agonist CL316243 in rat adipocytes