HIV-1 latency can be maintained in TKO-BLT mice over extended periods on ART and rapid viral rebound occurs following therapy removal. The additional 15-18 weeks of healthy longevity compared with other BLT models provides sufficient time to examine the decay kinetics of the latent reservoir as well as observe delays in recrudescence in HIV-1 cure studies.

Over-expression of the translesion synthesis polymerase (TLS pol) hpol κ in glioblastomas has been linked to a poor patient prognosis; however, the mechanism promoting higher expression in these tumors remains unknown. We determined that activation of the aryl hydrocarbon receptor (AhR) pathway in glioblastoma cells leads to increased hpol κ mRNA and protein levels. We blocked nuclear translocation and DNA binding by the AhR in glioblastoma cells using a small-molecule and observed decreased hpol κ expression. Pharmacological inhibition of tryptophan-2,3-dioxygenase (TDO), the enzyme largely responsible for activating the AhR in glioblastomas, led to a decrease in the endogenous AhR agonist kynurenine (Kyn) and a corresponding decrease in hpol κ protein levels. Importantly, we discovered that inhibiting TDO activity, AhR signaling, or suppressing hpol κ expression with RNA interference led to decreased chromosomal damage in glioblastoma cells. Epistasis assays further supported the idea that TDO activity, activation of AhR signaling and the resulting over-expression of hpol κ function primarily in the same pathway to increase endogenous DNA damage. These findings indicate that up-regulation of hpol κ through glioblastoma-specific TDO activity and activation of AhR signaling likely contributes to the high levels of replication stress and genomic instability observed in these tumors.

Coumadin (rac-warfarin) is the most commonly used anticoagulant in the world; however, its clinical use is often challenging because of its narrow therapeutic range and interindividual variations in response. A critical contributor to the uncertainty is variability in warfarin metabolism, which includes mostly oxidative but also reductive pathways. Reduction of each warfarin enantiomer yields two warfarin alcohol isomers, and the corresponding four alcohols retain varying levels of anticoagulant activity. Studies on the kinetics of warfarin reduction have often lacked resolution of parent-drug enantiomers and have suffered from coelution of pairs of alcohol metabolites; thus, those studies have not established the importance of individual stereospecific reductive pathways. We report the first steady-state analysis of - and-warfarin reduction in vitro by pooled human liver cytosol. As determined by authentic standards, the major metabolites were 9R,11S-warfarin alcohol for -warfarin and 9S,11S-warfarin alcohol for-warfarin. -warfarin ( 150 pmol/mg per minute, 0.67 mM) was reduced more efficiently than-warfarin ( 27 pmol/mg per minute, 1.7 mM). Based on inhibitor phenotyping, carbonyl reductase-1 dominated-and -warfarin reduction, followed by aldo-keto reductase-1C3 and then other members of that family. Overall, the carbonyl at position 11 undergoes stereospecific reduction by multiple enzymes to form the alcohol for both drug enantiomers, yet -warfarin undergoes reduction preferentially. This knowledge will aid in assessing the relative importance of reductive pathways for- and -warfarin and factors influencing levels of pharmacologically active parent drugs and metabolites, thus impacting patient dose responses.

Not all women infected with chlamydiae develop upper genital tract disease, but the reason(s) for this remains undefined. Host genetics and hormonal changes associated with the menstrual cycle are possible explanations for variable infection outcomes. It is also possible that disease severity depends on the virulence of the chlamydial inoculum. It is likely that the inoculum contains multiple genetic variants, differing in virulence. If the virulent variants dominate, then the individual is more likely to develop severe disease. Based on our previous studies, we hypothesized that the relative degree of virulence of a chlamydial population dictates the microRNA (miRNA) expression profile of the host, which, in turn, through regulation of the host inflammatory response, determines disease severity. Thus, we infected C57BL/6 mice with two populations of Chlamydia muridarum, each comprised of multiple genetic variants and differing in virulence: an attenuated strain (Nigg A ) and a virulent strain (Nigg V ). Nigg A and Nigg V elicited upper tract pathology in 54% and 91% of mice, respectively. miRNA expression analysis in Nigg V -infected mice showed significant downregulation of miRNAs involved in dampening fibrosis (miR-200b, miR-200b-5p, and 200b-3p miR-200a-3p) and in transcriptional regulation of cytokine responses (miR-148a-3p, miR-152-3p, miR-132, and miR-212) and upregulation of profibrotic miRNAs (miR-142, and miR-147). Downregulated miRNAs were associated with increased expression of interleukin 8 (IL-8), CXCL2, IL-1␤, tumor necrosis factor alpha (TNF-␣), and IL-6. Infection with Nigg V but not Nigg A led to decreased expression of Dicer and Ago 2, suggesting that Nigg V interaction with host cells inhibits expression of the miRNA biogenesis machinery, leading to increased cytokine expression and pathology.

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