Publications

Both the aa(3)-type cytochrome c oxidase from Rhodobacter sphaeroides (RsCcO(aa3)) and the closely related bo(3)-type ubiquinol oxidase from Escherichia coli (EcQO(bo3)) possess a proton-conducting D-channel that terminates at a glutamic acid, E286, which is critical for controlling proton transfer to the active site for oxygen chemistry and to a proton loading site for proton pumping. E286 mutations in each enzyme block proton flux and, therefore, inhibit oxidase function. In the current work, resonance Raman spectroscopy was used to show that the E286A and E286C mutations in RsCcO(aa3) result in long range conformational changes that influence the protein interactions with both heme a and heme a(3). Therefore, the severe reduction of the steady-state activity of the E286 mutants in RsCcO(aa3) to ~0.05% is not simply a result of the direct blockage of the D-channel, but it is also a consequence of the conformational changes induced by the mutations to heme a and to the heme a(3)-Cu(B) active site. In contrast, the E286C mutation of EcQO(bo3) exhibits no evidence of conformational changes at the two heme sites, indicating that its reduced activity (3%) is exclusively a result of the inhibition of proton transfer from the D-channel. We propose that in RsCcO(aa3), the E286 mutations severely perturb the active site through a close interaction with F282, which lies between E286 and the heme-copper active site. The local structure around E286 in EcQO(bo3) is different, providing a rationale for the very different effects of E286 mutations in the two enzymes. This article is part of a Special Issue entitled: Allosteric cooperativity in respiratory proteins.

OBJECTIVES

The aim of this study was to evaluate the effect of statin treatment in primary prevention of cardiovascular events in different race/ethnic groups.

BACKGROUND

Clinical trial evidence about the efficacy of statins in the primary prevention of cardiovascular events among nonwhites is uncertain.

METHODS

JUPITER trial, a randomized, double-blind, placebo-controlled evaluation of rosuvastatin 20 mg in the primary prevention of myocardial infarction (MI), stroke, arterial revascularization, hospitalization for unstable angina, and cardiovascular death included 12,683 whites and 5,117 nonwhites with low-density lipoprotein levels <130 mg/dL and high-sensitivity C-reactive protein levels ≥2.0 mg/L.

RESULTS

Random allocation to rosuvastatin resulted in a 45% reduction in the primary end point among whites (hazard ratio [HR] 0.55, 95% CI 0.43-0.69) and a 37% reduction among nonwhites (HR 0.63, 95% CI 0.41-0.99). Blacks (HR 0.65, 95% CI 0.35-1.22) and Hispanics (HR 0.58, 95% CI 0.25-1.39) had similar risk reductions. Among nonwhites in the placebo group, the stroke rate exceeded the MI rate (0.44 vs 0.20 per 100 person-years); an opposite pattern was observed among whites (0.31 vs 0.42 per 100 person-years). Nonwhites had higher death rates than whites (2.25 vs 0.93 per 100 person-years); however, all-cause mortality was similar at 20% with rosuvastatin treatment in both participant groups.

CONCLUSIONS

When used in primary prevention among individuals with low-density lipoprotein <130 mg/dL and high-sensitivity C-reactive protein ≥2 mg/L, rosuvastatin significantly reduced first MI, stroke, arterial revascularization, hospitalization for unstable angina, and cardiovascular death among whites and nonwhites.

Human Papillomavirus (HPV) is the main risk factor for cervical cancers and is associated with close to 36% of oropharyngeal cancers. There is increasing evidence that oral HPV transmission is related to sexual behavior but to our knowledge studies that involve women who have sex with women have not been performed. We examined the prevalence of oral HPV according to sexual behavior among a population-based sample of 118 women and have made some inferences of possible predictors of oral HPV infection. Women were categorized as heterosexual (history of vaginal sex and/or oral sex with males only, n = 75), bisexual (history of vaginal sex and oral sex with females, n = 32) and other (no history of vaginal sex but oral sex with females [homosexuals], virgins and women with incomplete sexual exposure data, n = 11) The prevalence of oral HPV infection was 12/118 (10.2%) for the overall study population and was not significantly different between heterosexual and bisexual women (10.7% (8/75) vs. 12.5% (4/32), p = 0.784). There was no oral HPV detected among homosexual women, virgins or among women where sexual exposure was unknown. Never smokers were more likely to be oral HPV+ compared to former smokers (Adjusted Odds Ratio (Adj OR) = 0.1, 95% CI, 0.0-1.1) and there was no difference in risk between never smokers and current smokers (Adj OR = 0.7, 95% CI, 0.1-4.6). Twenty-five percent (3/12) of oral HPV+ women had a history of HPV and/or genital warts compared to 9% (10/106) of oral HPV-women (p = 0.104). For the women with a history of vaginal sex (n = 110), oral HPV status was statistically significantly different according to oral sex exposure (p = 0.039). A higher proportion of oral HPV-positive women reported that they had no history of oral sex exposure compared to oral HPV-negative women (4/12, 33% vs. 7/98, 8%). The prevalence of cervical HPV infection did not vary between heterosexuals and bisexuals (35.7% (25/70) vs. 35.5% (11/31), p-value 0.411) and for all other women the cervical HPV prevalence was significantly lower (11.1%, 1/9). Our study suggests that smoking and sexual behavior involving males rather than female partners may be possible predictors of oral HPV infection in women. Further studies with larger sample size are needed to confirm these findings.

BACKGROUND

Epidemiologic evidence suggests a heritable component to risk for sudden cardiac arrest independent of risk for myocardial infarction. Recent candidate gene association studies for community sudden cardiac arrests have focused on a limited number of biological pathways and yielded conflicting results. We sought to identify novel gene associations for sudden cardiac arrest in patients with coronary artery disease by performing a genome-wide association study.

METHODS

Tagging SNPs (n = 338,328) spanning the genome were typed in a case-control study comparing 89 patients with coronary artery disease and sudden cardiac arrest due to ventricular tachycardia or ventricular fibrillation to 520 healthy controls.

RESULTS

Fourteen SNPs including 7 SNPs among 7 genes (ACYP2, AP1G2, ESR1, DGES2, GRIA1, KCTD1, ZNF385B) were associated with sudden cardiac arrest (all p < 1.30 × 10(-7)), following Bonferroni correction and adjustment for population substructure, age, and sex; genetic variation in ESR1 (p = 2.62 × 10(-8); Odds Ratio [OR] = 1.43, 95% confidence interval [CI]:1.277, 1.596) has previously been established as a risk factor for cardiovascular disease. In tandem, the role of 9 genes for monogenic long QT syndrome (LQT1-9) was assessed, yielding evidence of association with CACNA1C (LQT8; p = 3.09 × 10(-4); OR = 1.18, 95% CI:1.079, 1.290). We also assessed 4 recently published gene associations for sudden cardiac arrest, validating NOS1AP (p = 4.50 × 10(-2), OR = 1.15, 95% CI:1.003, 1.326), CSMD2 (p = 6.6 × 10(-3), OR = 2.27, 95% CI:1.681, 2.859), and AGTR1 (p = 3.00 × 10(-3), OR = 1.13, 95% CI:1.042, 1.215).

CONCLUSION

We demonstrate 11 gene associations for sudden cardiac arrest due to ventricular tachycardia/ventricular fibrillation in patients with coronary artery disease. Validation studies in independent cohorts and functional studies are required to confirm these associations.

BACKGROUND

Tumor immune tolerance can derive from the recruitment of suppressor cell populations, including myeloid-derived suppressor cells (MDSC). In cancer patients, MDSC accumulation correlates with increased tumor burden, but the mechanisms of MDSC induction remain poorly understood.

METHODS

This study examined the ability of human tumor cell lines to induce MDSC from healthy donor PBMC using in vitro co-culture methods. These human MDSC were then characterized for morphology, phenotype, gene expression, and function.

RESULTS

Of over 100 tumor cell lines examined, 45 generated canonical CD33+HLA-DR(low)Lineage- MDSC, with high frequency of induction by cervical, ovarian, colorectal, renal cell, and head and neck carcinoma cell lines. CD33+ MDSC could be induced by cancer cell lines from all tumor types with the notable exception of those derived from breast cancer (0/9, regardless of hormone and HER2 status). Upon further examination, these and others with infrequent CD33+ MDSC generation were found to induce a second subset characterized as CD11b+CD33(low)HLA-DR(low)Lineage-. Gene and protein expression, antibody neutralization, and cytokine-induction studies determined that the induction of CD33+ MDSC depended upon over-expression of IL-1β, IL-6, TNFα, VEGF, and GM-CSF, while CD11b+ MDSC induction correlated with over-expression of FLT3L and TGFβ. Morphologically, both CD33+ and CD11b+ MDSC subsets appeared as immature myeloid cells and had significantly up-regulated expression of iNOS, NADPH oxidase, and arginase-1 genes. Furthermore, increased expression of transcription factors HIF1α, STAT3, and C/EBPβ distinguished MDSC from normal counterparts.

CONCLUSIONS

These studies demonstrate the universal nature of MDSC induction by human solid tumors and characterize two distinct MDSC subsets: CD33+HLA-DR(low)HIF1α+/STAT3+ and CD11b+HLA-DR(low)C/EBPβ+, which should enable the development of novel diagnostic and therapeutic reagents for cancer immunotherapy.