Selective regulation of a defined subset of inflammatory and immunoregulatory genes by an NF-κB p50-IκBζ pathway.

The five NF-κB family members and three nuclear IκB proteins play important biological roles, but the mechanisms by which distinct members of these protein families contribute to selective gene transcription remain poorly understood, especially at a genome-wide scale. Using nascent transcript RNA-seq, we observed considerable overlap between p50-dependent and IκBζ-dependent genes in Toll-like receptor 4 (TLR4)-activated macrophages. Key immunoregulatory genes, including Il6, Il1b, Nos2, Lcn2, and Batf, are among the p50-IκBζ-codependent genes. IκBζ-bound genomic sites are occupied at earlier time points by NF-κB dimers. However, p50-IκBζ codependence does not coincide with preferential binding of either p50 or IκBζ, as RelA co-occupies hundreds of genomic sites with the two proteins. A common feature of p50-IκBζ-codependent genes is a nearby p50/RelA/IκBζ-cobound site exhibiting p50-dependent binding of both RelA and IκBζ. This and other results suggest that IκBζ acts in concert with RelA:p50 heterodimers. Notably, p50-IκBζ-codependent genes comprise a high percentage of genes exhibiting the greatest differential expression between TLR4-stimulated and tumor necrosis factor receptor (TNFR)-stimulated macrophages. Thus, our genome-centric analysis reveals a defined p50-IκBζ pathway that selectively activates a set of key immunoregulatory genes and serves as an important contributor to differential TNFR and TLR4 responses.

Expression-Based Cell Lineage Analysis in Drosophila Through a Course-Based Research Experience for Early Undergraduates.

A variety of genetic techniques have been devised to determine cell lineage relationships during tissue development. Some of these systems monitor cell lineages spatially and/or temporally without regard to gene expression by the cells, whereas others correlate gene expression with the lineage under study. The GAL4 Technique for Real-time and Clonal Expression (G-TRACE) system allows for rapid, fluorescent protein-based visualization of both current and past GAL4 expression patterns and is therefore amenable to genome-wide expression-based lineage screens. Here we describe the results from such a screen, performed by undergraduate students of the University of California, Los Angeles (UCLA) Undergraduate Research Consortium for Functional Genomics (URCFG) and high school summer scholars as part of a discovery-based education program. The results of the screen, which reveal novel expression-based lineage patterns within the brain, the imaginal disc epithelia, and the hematopoietic lymph gland, have been compiled into the G-TRACE Expression Database (GED), an online resource for use by the Drosophila research community. The impact of this discovery-based research experience on student learning gains was assessed independently and shown to be greater than that of similar programs conducted elsewhere. Furthermore, students participating in the URCFG showed considerably higher STEM retention rates than UCLA STEM students that did not participate in the URCFG, as well as STEM students nationwide.

Divergent antiviral effects of bioflavonoids on the hepatitis C virus life cycle.

We have previously demonstrated that quercetin, a bioflavonoid, blocks hepatitis C virus (HCV) proliferation by inhibiting NS5A-driven internal ribosomal entry site (IRES)-mediated translation of the viral genome. Here, we investigate the mechanisms of antiviral activity of quercetin and six additional bioflavonoids. We demonstrate that catechin, naringenin, and quercetin possess significant antiviral activity, with no associated cytotoxicity. Infectious virion secretion was not significantly altered by these bioflavonoids. Catechin and naringenin demonstrated stronger inhibition of infectious virion assembly compared to quercetin. Quercetin markedly blocked viral translation whereas catechin and naringenin demonstrated mild activity. Similarly quercetin completely blocked NS5A-augmented IRES-mediated translation in an IRES reporter assay, whereas catechin and naringenin had only a mild effect. Moreover, quercetin differentially inhibited HSP70 induction compared to catechin and naringenin. Thus, the antiviral activity of these bioflavonoids is mediated through different mechanisms. Therefore combination of these bioflavonoids may act synergistically against HCV.

Treatment of glenohumeral subluxation using electrothermal capsulorrhaphy.

PURPOSE: The purpose of this study was to review the results of a relatively homogenous group of patients with glenohumeral subluxation without labral pathology who were treated with an electrothermal capsulorrhaphy procedure. TYPE OF STUDY: Case series without controls. METHODS: From 1997 to 1998, 42 patients underwent electrothermal capsulorrhaphy using a monopolar radiofrequency probe (Oratec Interventions, Menlo Park, CA). Patients with prior capsular repairs, labral pathology that required repair, or capsular avulsion injuries were excluded from the study. Thirty-one patients met the inclusion criteria. Patients had a minimum of 2 years of follow-up (mean, 25 months), and a mean age of 25 years (range, 16 to 38 years). All of the patients had previously failed conservative treatment. There were 25 patients with unidirectional anterior instability, 2 patients with unidirectional inferior instability, 1 patient with unidirectional posterior instability, and 3 patients with multidirectional instability. The patients were assessed using a modified American Shoulder and Elbow Surgeons (ASES) score that examined pain (30 points), function (60 points), and patient satisfaction (10 points). In addition, subjective stability was assessed using a 10-point scale. RESULTS: The average modified ASES score increased to 88 points from 56 preoperatively (P < .01). The average subjective stability scale increased to 8.5 from 4.4 preoperatively (P < .01). Nineteen patients (61%) had an excellent result, 4 (13%) had a good result, 5 (16%) had a fair result, and 3 (10%) had a poor result; 22 of 26 patients who participated in sports were able to return to their preinjury level of play. The subset of patients with isolated anterior instability had results similar to the overall group. There were no instances of axillary neuritis or other neurologic injury. CONCLUSIONS: In carefully selected patients with shoulder instability, including unidirectional anterior instability without associated labral pathology, electrothermal capsulorrhaphy was effective and had few complications. LEVEL OF EVIDENCE: Level IV, case series without controls.

8-Nitroxanthine, a product of myeloperoxidase, peroxynitrite, and activated human neutrophils, enhances generation of superoxide by xanthine oxidase.

Reactive nitrogen and oxygen species are implicated in the damage of ischemic tissue that is reperfused. One important pathway may involve xanthine oxidase. Xanthine oxidase uses xanthine, a product of ATP degradation in ischemic tissue, to produce superoxide and hydrogen peroxide. Superoxide reacts rapidly with nitric oxide to form peroxynitrite, a powerful oxidant. Another potential source of reactive nitrogen species is the myeloperoxidase-hydrogen peroxide-nitrite system of activated phagocytes. We demonstrate that peroxynitrite and myeloperoxidase nitrate xanthine in vitro. Through 13C NMR spectroscopy, UV/visible spectroscopy, and mass spectrometry, the major product was identified as 8-nitroxanthine. Xanthine nitration by peroxynitrite was optimal at neutral pH and was markedly stimulated by physiological concentrations of bicarbonate. Xanthine nitration by myeloperoxidase required hydrogen peroxide and nitrite. However, it was independent of chloride ion and little affected by scavengers of hypochlorous acid, suggesting that the reactive agent is a nitrogen dioxide-like species. 8-Nitroxanthine was generated by a low, steady flux of peroxynitrite, and also by the myeloperoxidase-hydrogen peroxide-nitrite system of activated human neutrophils, suggesting that the reactions may be physiologically relevant. 8-Nitroxanthine may exert biological effects because it markedly increased the production of superoxide by the xanthine oxidase-xanthine system. Our observations suggest a mechanism for the enhanced formation of superoxide in reperfused tissue, which might increase the production of peroxynitrite and 8-nitroxanthine. Generation of 8-nitroxanthine by peroxynitrite and myeloperoxidase could represent a positive feedback mechanism that enhances further the production of both reactive oxygen and nitrogen species in ischemic tissue that is reperfused.

Synthesis and Characterization of Cobalt-Cage Complexes with Pendant Phenol Groups.

The synthesis and characterization of four compounds formed from the reductive amination of m- and o-hydroxybenzaldehyde to (1,8-diamino-3,6,10,13,16,19-hexaazabicyclo[6.6.6]eicosane)cobalt(III) are presented. These compounds are the mono- and dialkylated derivatives of the starting cobalt complex. The X-ray crystal structures of each compound, as its fully protonated chloride salt, have been obtained and are reported. The pK(a)'s of the compounds were determined by nonlinear least-squares analysis of data from potentiometric titrations and UV/vis spectrophotometry. The K(a)'s of the phenol groups of the compounds are reduced by roughly 1 order of magnitude compared to their analogous organic phenols. In the solid state, the compounds with one pendant phenol group (2, 4) are yellow and adopt the ob(3) conformation of their ethylene diamine rings in their crystal structures, while the compounds with two pendant phenol groups (3, 5) are orange and have the lel(3) conformation in their crystal structures. Solid-state reflectance UV/vis spectroscopy confirms these structural differences. In water, all four compounds form orange solutions and adopt the lel(3) conformation, as indicated by comparison of UV/vis spectroscopy and cyclic voltammetry properties with the literature.