Role of UDP-Glycosyltransferase (ugt) Genes in Detoxification and Glycosylation of 1-Hydroxyphenazine (1-HP) in Caenorhabditis elegans.

Caenorhabditis elegans is a useful model organism to study the xenobiotic detoxification pathways of various natural and synthetic toxins, but the mechanisms of phase II detoxification are understudied. 1-Hydroxyphenazine (1-HP), a toxin produced by the bacterium Pseudomonas aeruginosa, kills C. elegans. We previously showed that C. elegans detoxifies 1-HP by adding one, two, or three glucose molecules in N2 worms. Our current study evaluates the roles that some UDP-glycosyltransferase (ugt) genes play in 1-HP detoxification. We show that ugt-23 and ugt-49 knockout mutants are more sensitive to 1-HP than reference strains N2 or PD1074. Our data also show that ugt-23 knockout mutants produce reduced amounts of the trisaccharide sugars, while the ugt-49 knockout mutants produce reduced amounts of all 1-HP derivatives except for the glucopyranosyl product compared to the reference strains. We characterized the structure of the trisaccharide sugar phenazines made by C. elegans and showed that one of the sugar modifications contains an N-acetylglucosamine (GlcNAc) in place of glucose. This implies broad specificity regarding UGT function and the role of genes other than ogt-1 in adding GlcNAc, at least in small-molecule detoxification.

Vitamin D Deficiency, Inflammation, and Diminished Endogenous Regenerative Capacity in Coronary Heart Disease.

Background: Vitamin D deficiency (VDD) is associated with coronary heart disease (CHD) and poor outcomes, but supplementation does not improve prognosis. VDD has been implicated in and may promote greater risk through inflammation and impaired progenitor cell function. Objectives: The authors examined VDD, high-sensitivity C-reactive protein (hsCRP), circulating progenitor cell (CPC) counts, and outcomes in patients with CHD. They hypothesized that the higher risk with VDD is mediated by inflammation and impaired regenerative capacity. Methods: A total of 5,452 individuals with CHD in the Emory Cardiovascular Biobank had measurement of 25-hydroxyvitamin D, subsets of whom had hsCRP measurements and CPCs estimated as CD34-expressing mononuclear cell counts. Findings were validated in an independent cohort. 25-hydroxyvitamin D <20 ng/mL was considered VDD. Cox and Fine-Gray models determined associations between marker levels and: 1) all-cause mortality; 2) cardiovascular mortality; and 3) major adverse cardiovascular events, a composite of adverse CHD outcomes. Results: VDD (43.6% of individuals) was associated with higher adjusted cardiovascular mortality (HR: 1.57, 95% CI: 1.09-2.28). There were significant interactions between VDD and hsCRP and CPC counts in predicting cardiovascular mortality. Individuals with both VDD and elevated hsCRP had the greatest risk (HR: 2.82, 95% CI: 2.16-3.67). Only individuals with both VDD and low CPC counts were at high risk (HR: 2.25, 95% CI: 1.46-3.46). These findings were reproduced in the validation cohort. Conclusions: VDD predicts adverse outcomes in CHD. Those with VDD, inflammation and/or diminished regenerative capacity are at a significantly greater risk of cardiovascular mortality. Whether targeted supplementation in these high-risk groups improves risk warrants further study.