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ABSTRACT: Oleic acid (OA) is a nonesterified fatty acid that is released into the blood during lipomobilization at the time of calving in cows, a period where increased risk of infection and acute inflammation is observed. These data suggest potential OA-mediated regulation of innate immune responses. In the present study, we assessed the effects of OA on intracellular calcium release, ERK1/2 phosphorylation, superoxide production, CD11b expression and matrix metalloproteinase-9 (MMP-9) release in bovine neutrophils. Furthermore, the presence of GPR40, an OA receptor, was assessed by RT-PCR, immunoblotting and confocal microscopy. OA induced, in a dose-dependent manner, intracellular calcium mobilization, superoxide production and CD11b expression in bovine neutrophils; these effects were reduced by the intracellular chelating agent BAPTA-AM. OA also induced ERK2 phosphorylation and MMP-9 release. RT-PCR analysis detected mRNA expression of a bovine ortholog of the GPR40 receptor. Using a polyclonal antibody against human GPR40, we detected a protein of 31kDa by immunoblotting that was localized predominately in the plasma membrane. The selective agonist of GPR40, GW9508, induced intracellular calcium mobilization and ERK2 phosphorylation. In conclusion, OA can modulate bovine neutrophil responses in an intracellular calcium-dependent manner; furthermore, these responses could be induced by GPR40 activation.
Biochemical and Biophysical Research Communications 06/2011; 409(2):280-6. · 2.48 Impact Factor
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ABSTRACT: Interleukin-3 (IL-3) and granulocyte/macrophage colony-stimulating factor (GM-CSF) are two of the best-characterized cell survival factors in hematopoietic cells; these factors induce an increase in Akt activity in multiple cell lines, a process thought to be involved in cellular survival. It is known that growth factors require sustained glucose metabolism to promote cell survival. It has been determined that IL-3 and GM-CSF signal for increased glucose uptake in hematopoietic cells. Interestingly, receptors for IL-3 and GM-CSF are present in several non-hematopoietic cell types but their roles in these cells have been poorly described. In this study, we demonstrated the expression of IL-3 and GM-CSF receptors in HEK293 cells and analyzed their effect on glucose uptake. In these cells, both IL-3 and GM-CSF, increased glucose uptake. The results indicated that this increase involves the subcellular redistribution of GLUT1, affecting glucose transporter levels at the cell surface in HEK293 cells. Also the data directly demonstrates that the PI 3-kinase/Akt pathway is an important mediator of this process. Altogether these results show a role for non-insulin growth factors in the regulation of GLUT1 trafficking that has not yet been directly determined in non-hematopoietic cells.
Journal of Cellular Biochemistry 08/2010; 110(6):1471-80. · 2.87 Impact Factor
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ABSTRACT: The nuclear factor of activated T cells (NFAT) is a transcription factor essential for cytokine production during T-cell activation and is the target of several immunosuppressive drugs. Andrographolide is a diterpenic labdane that possesses anti-inflammatory and immunomodulatory effects. Several studies propose that andrographolide can reduce the immune response through inhibition of the nuclear factor kappa B (NF-kappaB) and mitogen-activated protein kinases (MAPK) such as extracellular signal regulated kinase 1/2 (ERK1/2) pathways. Moreover, andrographolide reduces IFN-gamma and IL-2 production induced by concanavalin A in murine T-cell. Nevertheless, the mechanisms involved in the decrease of cytokine production are unknown. In the present study, we determined that andrographolide reduced IL-2 production in Jurkat cells stimulated with phorbol myristate acetate and ionomycin (PMA/Ionomycin). We then showed that andrographolide reduced NFAT luciferase activity and interfered with its nuclear distribution, with these effects being linked to an increase in c-jun-N-terminal kinase (JNK) phosphorylation. Additionally, reduction of NF-kappaB activity in Jurkat cells treated with andrographolide was observed. Using Western blotting, we demonstrated that andrographolide decreased ERK1 and ERK5 phosphorylation induced by anti-CD3 or PMA/Ionomycin. Andrographolide did not affect cell viability at concentration of 10 and 50 muM; however, our results suggest that andrographolide increase early apoptosis at 100 muM. We concluded that andrographolide can exert immunomodulatory effects by interfering with NFAT activation and ERK1 and ERK5 phosphorylation in T-cells.
European journal of pharmacology 12/2008; 602(2-3):413-21. · 2.59 Impact Factor
