Fibroblasts derived from the lungs of patients with idiopathic pulmonary fibrosis (IPF) and systemic sclerosis (SSc) produce low levels of prostaglandin (PG) E 2 , due to a limited capacity to up-regulate cyclooxygenase-2 (COX-2). This deficiency contributes functionally to the fibroproliferative state, however the mechanisms responsible are incompletely understood. In the present study, we examined whether the reduced level of COX-2 mRNA expression observed in fibrotic lung fibroblasts is regulated epigenetically. The DNA methylation inhibitor, 5-aza-2′-deoxycytidine (5AZA) restored COX-2 mRNA expression by fibrotic lung fibroblasts dose dependently. Functionally, this resulted in normalization of fibroblast phenotype in terms of PGE 2 production, collagen mRNA expression and sensitivity to apoptosis. COX-2 methylation assessed by bisulfite sequencing and methylation microarrays was not different in fibrotic fibroblasts compared with controls. However, further analysis of the methylation array data identified a transcriptional regulator, chromosome 8 open reading frame 4 (thyroid cancer protein 1, TC-1) (c8orf4), which is hypermethylated and down-regulated in fibrotic fibroblasts compared with controls. siRNA knockdown of c8orf4 in control fibroblasts down-regulated COX-2 and PGE 2 production generating a phenotype similar to that observed in fibrotic lung fibroblasts. Chromatin immunoprecipitation demonstrated that c8orf4 regulates COX-2 expression in lung fibroblasts through binding of the proximal promoter. We conclude that the decreased capacity of fibrotic lung fibroblasts to up-regulate COX-2 expression and COX-2-derived PGE 2 synthesis is due to an indirect epigenetic mechanism involving hypermethylation of the transcriptional regulator, c8orf4.

Cardiovascular pathologies are still the primary cause of death worldwide. The molecular mechanisms behind these pathologies have not been fully elucidated. Unravelling them will bring us closer to therapeutic strategies to prevent or treat cardiovascular disease. One of the major transcription factors that has been linked to both cardiovascular health and disease is NF-κB (nuclear factor κB). The NF-κB family controls multiple processes, including immunity, inflammation, cell survival, differentiation and proliferation, and regulates cellular responses to stress, hypoxia, stretch and ischaemia. It is therefore not surprising that NF-κB has been shown to influence numerous cardiovascular diseases including atherosclerosis, myocardial ischaemia/reperfusion injury, ischaemic preconditioning, vein graft disease, cardiac hypertrophy and heart failure. The function of NF-κB is largely dictated by the genes that it targets for transcription and varies according to stimulus and cell type. Thus NF-κB has divergent functions and can protect cardiovascular tissues from injury or contribute to pathogenesis depending on the cellular and physiological context. The present review will focus on recent studies on the function of NF-κB in the cardiovascular system.

1. Serial measurements of total body calcium have been made by prompt γ-neutron activation analysis in 13 patients with inflammatory bowel disease over a mean period of 23 months. Changes in spinal trabecular bone mineral density and radial shaft bone mineral content were also assessed by using quantitative computed tomography and single photon absorptiometry, respectively. 2. The mean annual decreases (95% confidence intervals) were: total body calcium, 7.8% (−12.0 to −3.7%; P <0.001); spinal trabecular bone mineral density, 2.5% (−5.0 to +0.1%; 0.05 < P <0.1), radial bone mineral content, 2.1% (−3.4 to −0.8%; P <0.01). 3. No significant correlations were found between rates of change of the three variables. However, there were significant positive correlations between the baseline values for total body calcium and radial bone mineral content ( r = 0.638, P <0.05), spinal bone mineral density and radial bone mineral content ( r = 0.854, P <0.01), and total body calcium and spinal bone mineral density ( r = 0.876, P <0.001). 4. These results demonstrate rapid decreases in total body calcium in patients with inflammatory bowel disease which, in conjunction with the significant decrease in radial shaft bone mineral content, indicate increased rates of cortical bone loss. Whilst values for bone mass at different skeletal sites showed positive correlations within individuals, no relationship was found between the rates of change in bone mass at these sites. 5. The rapid bone loss observed in some subjects emphasizes the importance of early detection of osteoporosis by bone densitometry and the need for effective prophylactic measures to be established in this group of patients.