Article

Epoxyeicosatrienoic acid agonist regulates human mesenchymal stem cell-derived adipocytes through activation of HO-1-pAKT signaling and a decrease in PPARγ.

Department of Physiology and Pharmacology, University of Toledo College of Medicine, Toledo, Ohio 43614, USA.
Stem cells and development (Impact Factor: 4.2). 12/2010; 19(12):1863-73. DOI: 10.1089/scd.2010.0098
Source: PubMed

ABSTRACT Human mesenchymal stem cells (MSCs) expressed substantial levels of CYP2J2, a major CYP450 involved in epoxyeicosatrienoic acid (EET) formation. MSCs synthesized significant levels of EETs (65.8 ± 5.8 pg/mg protein) and dihydroxyeicosatrienoic acids (DHETs) (15.83 ± 1.62 pg/mg protein), suggesting the presence of soluble epoxide hydrolase (sEH). The addition of an sEH inhibitor to MSC culture decreased adipogenesis. EETs decreased MSC-derived adipocytes in a concentration-dependent manner, 8,9- and 14,15-EET having the maximum reductive effect on adipogenesis. We examined the effect of 12-(3-hexylureido)dodec-8(Z)-enoic acid, an EET agonist, on MSC-derived adipocytes and demonstrated an increased number of healthy small adipocytes, attenuated fatty acid synthase (FAS) levels (P < 0.01), and reduced PPARγ, C/EBPα, FAS, and lipid accumulation (P < 0.05). These effects were accompanied by increased levels of heme oxygenase (HO)-1 and adiponectin (P < 0.05), and increased glucose uptake (P < 0.05). Inhibition of HO activity or AKT by tin mesoporphyrin (SnMP) and LY2940002, respectively, reversed EET-induced inhibition of adipogenesis, suggesting that activation of the HO-1-adiponectin axis underlies EET effect in MSCs. These findings indicate that EETs decrease MSC-derived adipocyte stem cell differentiation by upregulation of HO-1-adiponectin-AKT signaling and play essential roles in the regulation of adipocyte differentiation by inhibiting PPARγ, C/EBPα, and FAS and in stem cell development. These novel observations highlight the seminal role of arachidonic acid metabolism in MSCs and suggest that an EET agonist may have potential therapeutic use in the treatment of dyslipidemia, diabetes, and the metabolic syndrome.

Download full-text

Full-text

Available from: John R Falck, Jun 19, 2015
0 Followers
 · 
163 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Patho-physiological conditions with high oxidative stress, such as conditions associated with increased denatured heme-proteins, are associated with enhanced adipogenic response. This effect predominantly manifests as adipocyte hypertrophy characterized by dysfunctional, pro-inflammatory adipocytes exhibiting reduced expression of anti-inflammatory hormone, adiponectin. To understand how increased levels of cellular heme, a pro-oxidant molecule, modulates adipogenesis; the following study was designed to evaluate effects of heme on adipogenesis in human mesenchymal stem cells (hMSCs) and mouse pre-adipocytes (3T3L1). Experiments were conducted in the absence and in the presence of a superoxide dismutase (SOD) mimetic (tempol, 100 µM). Heme (10 µM) increased (P<0.05) adipogenesis in hMSCs and mouse pre-adipocytes, where tempol alone (100 µmol/L) attenuated adipogenesis in these cells (P<0.05). Tempol also reversed heme-induced increase in adipogenesis in both hMSCs and mouse pre-adipocytes (P<0.05). In addition, heme exposed 3T3L1 exhibited reduced (P<0.05) expression of transcriptional regulator-sirtuin 1 (Sirt1), along with, increased (P<0.05) expression of adipogenic markers peroxisome proliferators-activated receptor-gamma (PPARγ), C/EBPα, and aP2. These effects of heme were rescued (P<0.05) in cells concurrently treated with heme and tempol (P<0.05) and prevented in cells over-expressing Sirt1. Taken together, our results indicate that heme-induced oxidative stress inhibits Sirt1, thus un-inhibiting adipogenic regulators such as PPARγ and C/EBPα; which in turn induce increased adipogenesis along with adipocyte hypertrophy in pre-adipocytes. Anti-oxidant induced offsetting of these effects of heme supports the role of heme-dependent oxidative stress in mediating such events.
    Journal of Cellular Biochemistry 06/2012; 113(6):1926-35. DOI:10.1002/jcb.24061 · 3.37 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Mesenchymal stromal cells deploy immune suppressive properties amenable for use as cell therapy for inflammatory disorders. It is now recognized that mesenchymal stromal cells necessitate priming with an inflammatory milieu, in particular interferon-γ, to exert augmented immunosuppressive effects. It has been recently suggested that the heme-catabolizing enzyme heme oxygenase-1 is an essential component of the mesenchymal stromal cell–driven immune suppressive response. Because mesenchymal stromal cells upregulate indoleamine 2,3-dioxygenase expression on interferon-γ priming and indoleamine 2,3-dioxygenase requires heme as a cofactor for optimal catabolic function, we investigated the potential antagonism of heme oxygenase-1 activity on indoleamine 2, 3-dioxygenase and the impact on mesenchymal stromal cell immune plasticity. We herein sought to evaluate the molecular genetic effect of cytokine priming on human mesenchymal stromal cell heme oxygenase-1 expression and its functional role in differentially primed mesenchymal stromal cells. Contrary to previous reports, messenger RNA and protein analyses demonstrated that mesenchymal stromal cells derived from normal subjects (n = 6) do not express heme oxygenase-1 at steady state or after interferon-γ, tumor necrosis factor-α, and/or transforming growth factor-β priming. Pharmacological inhibition of heme oxygenase-1 with the use of tin protoporphyrin did not significantly abrogate the ability of mesenchymal stromal cells to suppress T-cell proliferation in vitro. Overall, these results unequivocally demonstrate that under steady state and after cytokine priming, human mesenchymal stromal cells immunoregulate T-cell proliferation independent of heme oxygenase-1.
    Cytotherapy 01/2015; DOI:10.1016/j.jcyt.2014.11.010 · 3.10 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Cardiovascular risk factors contribute to enhanced oxidative stress which leads to endothelial dysfunction. These events trigger platelet activation and their interaction with leukocytes and endothelial cells, thus contributing to the induction of chronic inflammatory processes at the vascular wall and to the development of atherosclerotic lesions and atherothrombosis. In this scenario, endogenous antioxidant pathways are induced to restrain the development of vascular disease. In the present paper, we will discuss the role of heme oxygenase (HO)-1 which is an enzyme of the heme catabolism and cleaves heme to form biliverdin and carbon monoxide (CO). Biliverdin is reduced enzymatically to the potent antioxidant bilirubin. Recent evidence supports the involvement of HO-1 in the antioxidant and antiinflammatory effect of cyclooxygenase(COX)-2-dependent prostacyclin in the vasculature. Moreover, the role of HO-1 in estrogen vasoprotection is emerging. Finally, possible strategies to develop novel therapeutics against cardiovascular disease by targeting the induction of HO-1 will be discussed.
    02/2012; 2012:127910. DOI:10.1155/2012/127910