Statins modulate transcriptional activity of heme‐oxygenase‐1 promoter in NIH 3T3 Cells

Abstract

Statins, inhibitors of HMG CoA reductase, have pleiotropic effects independent of their capacity to lower cholesterol. Heme-oxygenase-1(HO-1) plays an important role as an anti-oxidant and anti-inflammatory enzyme. In the present study, we used NIH 3T3 cells which express HO-1 to investigate the molecular mechanisms of HO-1 induction by statins. Simvastatin or fluvastatin induced a significant increase in HO-1 protein expression and mRNA levels. Both statins stimulated activity of a mouse HO-1 promoter (-1,287 to +73 bp)/luciferase reporter gene, 3.25 ± 0.23 (Mean ± S.E.M., n = 15, P < 0.001, t-test) and 3.13 ± 0.33 (Mean ± S.E.M., n = 6, P < 0.001, t-test), respectively. This effect was more pronounced in the short proximal promoter than the full promoter of HO-1. Gel retardation experiments for C/EBP and upstream stimulatory factor (USF) DNA-binding activities using simvastatin- or fluvastatin-treated cells showed significant nuclear protein-DNA complexes which were supershifted with antibodies specific for C/EBP β and δ or USF-1 and USF-2. Point mutations of the proximal HO-1 promoter (-149 to +73 bp) for the myc/max which binds USF or the C/EBP binding sequences showed a reduction in statin-induced reporter activity whereas no role of the distal C/EBP binding elements located at -4 kb was observed. Moreover, overexpression of mutated C/EBP β and USF factor or the siRNA for both factors supported a role of these transcription factors in statin-dependent induction of HO-1, with a clearer effect for C/EBP.

Translational Significance of Heme Oxygenase in Obesity and Metabolic Syndrome

“…Niacin has additionally been shown to induce the HO-1 gene to counter cardiovascular disease 226 and may have a beneficial effect on obesity-induced hypertension. Further, certain statins have activated the HO-1 promoter in mouse pre-adipocytes, preventing adipocyte differentiation, suggesting this class of drugs can combat adiposity and adipogenesis 227 . Additionally, analogs of EET targeting β-catenin/SIRT1 will represent novel small molecules enhancing bilirubin downstream signaling to prevent pre-adipocyte full differentiation and inflammation and protect against obesity and diabetes.…”

ROS Stress Resets Circadian Clocks to Coordinate Pro-Survival Signals

“…Our data do not exclude the contribution of the pathway via direct Nrf2 phosphorylation by CK2 [62]. Additionally, cOS-up-regulated genes encoding the heterodimeric partner of Nrf2 ( Maff, Mafg, Mafk ) [63,64], a transcription factor for the anti-oxidant genes ( Cebpb ) [65] (Figure 7B and S7) and other proteins in oxidative stress-responsive pathways (Figures S8), might contribute to cell survival. NF-kappa-B-mediated up-regulation Sod1 and Sod2 [66] after cOS-pulse is controlled by BMAL1 and CK2-mediated BMAL1-S90 phosphorylation, as evidenced by SOD1/2 quantitation after cOS-pulse (Figure S9) and the result in Figure 6D.…”

Overview of Community-Acquired Pneumonia and the Role of Inflammatory Mechanisms in the Immunopathogenesis of Severe Pneumococcal Disease

“…The consequence is decreased activation of NF κ B and resultant interference with the transcription of genes encoding various proinflammatory proteins such as inducible nitric oxide synthase, cyclooxygenase-2 and matrix metalloproteinase-9 [176, 178]. Secondly, via induction of heme oxygenase-1 expression, also resulting in attenuation of activation of NF κ B, as well as decreased production of ROS in the setting of increased production of anti-inflammatory IL-10 [178, 179]. …”