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Gonzalez-Flores A.,Institute of Parasitology and Biomedicine Lo pez Neyra | Aguilar-Quesada R.,Institute of Parasitology and Biomedicine Lo pez Neyra | Siles E.,University of Jae N | Pozo S.,CIC bioGUNE | And 9 more authors.
Oncogene | Year: 2014

Hypoxia-inducible factors (HIFs) mediate the transcriptional adaptation of hypoxic cells. The extensive transcriptional programm regulated by HIFs involves the induction of genes controlling angiogenesis, cellular metabolism, cell growth, metastasis, apoptosis, extracellular matrix remodeling and others. HIF is a heterodimer of HIF- and HIF-β subunits. In addition to HIF-1, HIF-2 has evolved as an isoform that contributes differently to the hypoxic adaptation by performing non-redundant functions. Poly (ADP-ribose) polymerase-1 (PARP-1) is a nuclear protein involved in the control of DNA repair and gene transcription by modulating chromatin structure and acting as part of gene-specific enhancer/promoter-binding complexes. Previous results have shown that PARP-1 regulates HIF-1 activity. In this study, we focused on the cross-talk between HIF-2 and PARP-1. By using different approaches to suppress PARP-1, we show that HIF-2 mRNA expression, protein levels and HIF-2-dependent gene expression, such as ANGPTL4 and erythropoietin (EPO), are regulated by PARP-1. This regulation occurs at both the transcriptional and post-trancriptional level. We also show a complex formation between HIF-2 with PARP-1. This complex is sensitive to PARP inhibition and seems to protect against the von Hippel-Lindau-dependent HIF-2 degradation. Finally, we show that parp-1-/-mice display a significant reduction in the circulating hypoxia-induced EPO levels, number of red cells and hemoglobin concentration. Altogether, these results reveal a complex functional interaction between PARP-1 and the HIF system and suggest that PARP-1 is involved in the fine tuning of the HIF-mediated hypoxic response in vivo. © 2014 Macmillan Publishers Limited. Source


Garci a-Bermu dez M.,Institute of Parasitology and Biomedicine Lo pez Neyra | Lo pez-Meji as R.,systemIC | Genre F.,systemIC | Castan&tild;eda S.,Hospital Universitario La Paz | And 17 more authors.
Arthritis Research and Therapy | Year: 2014

Introduction: Rheumatoid arthritis (RA) is a complex polygenic inflammatory disease associated with accelerated atherosclerosis and increased cardiovascular (CV) disease risk. Interferon regulatory factor 5 (IRF5) is a regulator of type I interferon induction. Recently, researchers have described an association between multiple single-nucleotide polymorphisms of the IRF5 gene and some rheumatic disorders. In this study, we aimed to evaluate whether three different haplotype blocks within the IRF5 locus which have been shown to alter the protein function are involved in the risk of CV events occurring in Spanish RA patients. Methods: Three IRF5 polymorphisms (rs2004640, rs2070197 and rs10954213) representative of each haplotype group were genotyped by performing TaqMan assays using a 7900HT Fast Real-Time PCR System with tissue from a total of 2,137 Spanish patients diagnosed with RA. Among them, 390 (18.2%) had experienced CV events. The relationship of IRF5 genotypes and haplotypes to CV events was tested using Cox regression. Results: Male sex, age at RA diagnosis and most traditional risk factors (hypertension, dyslipidemia and smoking habit) were associated with increased risk for CV events in the RA population. Interestingly, a protective effect of both IRF5 rs2004640 GG and IRF5 rs10954213 GG genotypes against the risk for CV events after adjusting the results for sex, age at RA diagnosis and traditional CV disease risk factors was observed (hazard ratio (HR) = 0.6, 95% confidence interval (CI) = 0.38 to 0.92, P = 0.02; and HR = 0.58, 95% CI = 0.36 to 0.95, P = 0.03, respectively). Moreover, we detected a protective effect of the GTG haplotype against the risk for CV events after adjusting the results for potential confounding factors (HR = 0.72, 95% CI = 0.56 to 0.93, P = 0.012). Conclusions: Our results reveal that IRF5 gene variants are associated with risk of CV events in patients with RA. © 2014 Garci´a-Bermu´dez et al.; licensee BioMed Central Ltd. Source

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