Planavila Anna, Sánchez Rosa M, Merlos Manuel, Laguna Juan C, Vázquez-Carrera Manuel
Unidad de Farmacología, Departamento de Farmacología y Química Terapéutica, Facultad de Farmacia, Universidad de Barcelona, Spain.
Biochim Biophys Acta. 2005 Sep 15;1736(2):120-7. doi: 10.1016/j.bbalip.2005.08.001.
Although abnormalities in cardiac fatty acid metabolism are involved in the development of several cardiac pathologies, the mechanisms underlying these changes are not well understood. Given the prominent role played by peroxisome proliferator-activated receptor beta/delta (PPARbeta/delta in cardiac fatty acid metabolism, the aim of this study was to examine the effects of nuclear factor (NF)-kappaB activation on the activity of this nuclear receptor. Embryonic rat heart-derived H9c2 cells stimulated with lipopolysaccharide (LPS) showed a reduction (38%, P<0.05) in the mRNA levels of the PPARbeta/delta-target gene pyruvatedehydrogenase kinase 4 (PDK4) that was prevented in the presence of the NF-kappaB inhibitors parthenolide (10 microM) and atorvastatin (10 microM). Electrophoretic mobility shift assay revealed that both parthenolide and atorvastatin significantly decreased LPS-stimulated NF-kappaB binding activity in H9c2 cardiac cells. LPS-stimulation of H9c2 cardiac cells also led to a 30% reduction (P<0.05) in the mRNA levels of PPARgamma Coactivator 1 (PGC-1) that was consistent with the reduction in the protein levels of this coactivator. In the presence of either atorvastatin or parthenolide, the reduction in PGC-1 expression was prevented. Co-immunoprecipitation studies showed that LPS-stimulation led to a reduction in the physical interaction between PGC-1 and PPARbeta/delta and that this reduction was prevented in the presence of atorvastatin. Finally, electrophoretic mobility shift assay revealed that parthenolide and atorvastatin prevented LPS-mediated reduction in PPARbeta/delta binding activity in H9c2 cardiac cells. These results suggest that LPS-mediated NF-kappaB activation inhibits the expression of genes involved in fatty acid metabolism by a mechanism involving reduced expression of PGC-1, which in turn affects the PPARbeta/delta transactivation of target genes involved in cardiac fatty acid oxidation.
尽管心脏脂肪酸代谢异常与多种心脏疾病的发生有关，但其潜在机制尚未完全明确。鉴于过氧化物酶体增殖物激活受体β/δ（PPARβ/δ）在心脏脂肪酸代谢中发挥的重要作用，本研究旨在探讨核因子（NF）-κB激活对该核受体活性的影响。用脂多糖（LPS）刺激胚胎大鼠心脏来源的H9c2细胞后，PPARβ/δ靶基因丙酮酸脱氢酶激酶4（PDK4）的mRNA水平降低了38%（P<0.05），而在存在NF-κB抑制剂小白菊内酯（10 microM）和阿托伐他汀（10 microM）的情况下，这种降低得到了预防。电泳迁移率变动分析显示，小白菊内酯和阿托伐他汀均显著降低了H9c2心脏细胞中LPS刺激的NF-κB结合活性。LPS刺激H9c2心脏细胞还导致PPARγ共激活因子1（PGC-1）的mRNA水平降低了30%（P<0.05），这与该共激活因子蛋白水平的降低一致。在存在阿托伐他汀或小白菊内酯的情况下，PGC-1表达的降低得到了预防。免疫共沉淀研究表明，LPS刺激导致PGC-1与PPARβ/δ之间的物理相互作用减少，而在存在阿托伐他汀的情况下，这种减少得到了预防。最后，电泳迁移率变动分析显示，小白菊内酯和阿托伐他汀可预防LPS介导的H9c2心脏细胞中PPARβ/δ结合活性的降低。这些结果表明，LPS介导的NF-κB激活通过一种涉及PGC-1表达降低的机制抑制脂肪酸代谢相关基因的表达，进而影响参与心脏脂肪酸氧化的靶基因的PPARβ/δ反式激活。
