Response to letter regarding article by Patel et al: A Novel Biomarker of Oxidative Stress is Associated with Risk of Death in Patients with Coronary Artery Disease

We thank Drs Giral and colleagues for their interest in our work.1 They raise the important query of whether our findings would still persist after adjustment for γ-glutamyltransferase (GGT), given that GGT activity hydrolyzes glutathione (GSH) to produce glutamate+cysteinylglycine. This point, however, is not relevant to our description of GSH/cystine as a useful biomarker of cardiovascular disease, because our samples were all collected with a preservation solution containing a GGT

A Novel Biomarker of Oxidative Stress is Associated with Risk of Death in Patients with Coronary Artery Disease

Background—Free radical scavengers have failed to improve patient outcomes promoting the concept that clinically important oxidative stress (OS) may be mediated by alternative mechanisms. We sought to examine the association of emerging aminothiol markers of non-free radical mediated oxidative stress with clinical outcomes. Methods and Results—Plasma levels of reduced (cysteine and glutathione) and oxidized (cystine and glutathione disulphide) aminothiols were quantified by high performance liquid chromatography in 1411 patients undergoing coronary angiography (mean age 63 years, male 66%). All patients were followed for a mean of 4.7±2.1 years for the primary outcome of all-cause death (n=247). Levels of cystine (oxidized) and glutathione (reduced) were associated with risk of death (p\u3c0.001 both) before and after adjustment for covariates. High cystine and low glutathione levels (\u3e+1 SD & \u3c-1 SD respectively) were associated with higher mortality (adjusted HR 1.63 (95% CI 1.19-2.21; HR 2.19 (95% CI 1.50-3.19), respectively) compared to those outside these thresholds. Furthermore, the ratio of cystine/glutathione was also significantly associated with mortality (adjusted HR 1.92 (95% CI 1.39-2.64) and was independent of and additive to hs-CRP level. Similar associations were found for other outcomes of cardiovascular death and combined death and myocardial infarction. Conclusions—A high burden of OS, quantified by the plasma aminothiols, cystine, glutathione and their ratio is associated with mortality in patients with CAD, a finding that is independent of and additive to the inflammatory burden. Importantly, this data supports the emerging role of non-free radical biology in driving clinically important oxidative stress

Characterization of a novel role of inhibitor of growth 2 (ing2) in cell differentiation

Bibliography: p. 158-174Some pages are in colour

Roles of Ring-Hydroxylating Dioxygenases in Styrene and Benzene Catabolism in Rhodococcus jostii RHA1▿ †

Proteomics and targeted gene disruption were used to investigate the catabolism of benzene, styrene, biphenyl, and ethylbenzene in Rhodococcus jostii RHA1, a well-studied soil bacterium whose potent polychlorinated biphenyl (PCB)-transforming properties are partly due to the presence of the related Bph and Etb pathways. Of 151 identified proteins, 22 Bph/Etb proteins were among the most abundant in biphenyl-, ethylbenzene-, benzene-, and styrene-grown cells. Cells grown on biphenyl, ethylbenzene, or benzene contained both Bph and Etb enzymes and at least two sets of lower Bph pathway enzymes. By contrast, styrene-grown cells contained no Etb enzymes and only one set of lower Bph pathway enzymes. Gene disruption established that biphenyl dioxygenase (BPDO) was essential for growth of RHA1 on benzene or styrene but that ethylbenzene dioxygenase (EBDO) was not required for growth on any of the tested substrates. Moreover, whole-cell assays of the ΔbphAa and etbAa1::cmrA etbAa2::aphII mutants demonstrated that while both dioxygenases preferentially transformed biphenyl, only BPDO transformed styrene. Deletion of pcaL of the β-ketoadipate pathway disrupted growth on benzene but not other substrates. Thus, styrene and benzene are degraded via meta- and ortho-cleavage, respectively. Finally, catalases were more abundant during growth on nonpolar aromatic compounds than on aromatic acids. This suggests that the relaxed specificities of BPDO and EBDO that enable RHA1 to grow on a range of compounds come at the cost of increased uncoupling during the latter's initial transformation. The stress response may augment RHA1's ability to degrade PCBs and other pollutants that induce similar uncoupling

Identification of a Novel Function for the Chromatin Remodeling Protein ING2 in Muscle Differentiation

<div><p>The inhibitor of growth (ING) family of zinc-finger plant homeodomain (PHD)-containing chromatin remodeling protein controls gene expression and has been implicated in the regulation of cell proliferation and death. However, the role of ING proteins in cell differentiation remains largely unexplored. Here, we identify an essential function for ING2 in muscle differentiation. We find that knockdown of ING2 by RNA interference (RNAi) blocks the differentiation of C2C12 cells into myotubes, suggesting that ING2 regulates the myogenic differentiation program. We also characterize a mechanism by which ING2 drives muscle differentiation. In structure-function analyses, we find that the leucine zipper motif of ING2 contributes to ING2-dependent muscle differentiation. By contrast, the PHD domain, which recognizes the histone H3K4me3 epigenetic mark, inhibits the ability of ING2 to induce muscle differentiation. We also find that the Sin3A-HDAC1 chromatin remodeling complex, which interacts with ING2, plays a critical role in ING2-dependent muscle differentiation. These findings define a novel function for ING2 in muscle differentiation and bear significant implications for our understanding of the role of the ING protein family in cell differentiation and tumor suppression.</p> </div