RC3H1 post-transcriptionally regulates A20 mRNA and modulates the activity of the IKK/NF-kappa B pathway

The RNA-binding protein RC3H1 (also known as ROQUIN) promotes TNF alpha mRNA decay via a 3'UTR constitutive decay element (CDE). Here we applied PAR-CLIP to human RC3H1 to identify similar to 3, 800 mRNA targets with 416, 000 binding sites. A large number of sites are distinct from the consensus CDE and revealed a structure-sequence motif with U-rich sequences embedded in hairpins. RC3H1 binds preferentially short-lived and DNA damage-induced mRNAs, indicating a role of this RNA-binding protein in the post-transcriptional regulation of the DNA damage response. Intriguingly, RC3H1 affects expression of the NF-kappa B pathway regulators such as I kappa B alpha and A20. RC3H1 uses ROQ and Zn-finger domains to contact a binding site in the A20 30UTR, demonstrating a not yet recognized mode of RC3H1 binding. Knockdown of RC3H1 resulted in increased A20 protein expression, thereby interfering with I kappa B kinase and NF-kappa B activities, demonstrating that RC3H1 can modulate the activity of the IKK/NF-kappa B pathway

The Structural Basis of Gas-Responsive Transcription by the Human Nuclear Hormone Receptor REV-ERBβ

Heme is a ligand for the human nuclear receptors (NR) REV-ERBα and REV-ERBβ, which are transcriptional repressors that play important roles in circadian rhythm, lipid and glucose metabolism, and diseases such as diabetes, atherosclerosis, inflammation, and cancer. Here we show that transcription repression mediated by heme-bound REV-ERBs is reversed by the addition of nitric oxide (NO), and that the heme and NO effects are mediated by the C-terminal ligand-binding domain (LBD). A 1.9 Å crystal structure of the REV-ERBβ LBD, in complex with the oxidized Fe(III) form of heme, shows that heme binds in a prototypical NR ligand-binding pocket, where the heme iron is coordinately bound by histidine 568 and cysteine 384. Under reducing conditions, spectroscopic studies of the heme-REV-ERBβ complex reveal that the Fe(II) form of the LBD transitions between penta-coordinated and hexa-coordinated structural states, neither of which possess the Cys384 bond observed in the oxidized state. In addition, the Fe(II) LBD is also able to bind either NO or CO, revealing a total of at least six structural states of the protein. The binding of known co-repressors is shown to be highly dependent upon these various liganded states. REV-ERBs are thus highly dynamic receptors that are responsive not only to heme, but also to redox and gas. Taken together, these findings suggest new mechanisms for the systemic coordination of molecular clocks and metabolism. They also raise the possibility for gas-based therapies for the many disorders associated with REV-ERB biological functions

Different Inhibitory Potencies of Oseltamivir Carboxylate, Zanamivir, and Several Tannins on Bacterial and Viral Neuraminidases as Assessed in a Cell-Free Fluorescence-Based Enzyme Inhibition Assay

Neuraminidase is a key enzyme in the life cycle of influenza viruses and is present in some bacterial pathogens. We here assess the inhibitory potency of plant tannins versus clinically used inhibitors on both a viral and a bacterial model neuraminidase by applying the 2′-(4-methylumbelliferyl)-α-d-N-acetylneuraminic acid (MUNANA)-based activity assay. A range of flavan-3-ols, ellagitannins and chemically defined proanthocyanidin fractions was evaluated in comparison to oseltamivir carboxylate and zanamivir for their inhibitory activities against viral influenza A (H1N1) and bacterial Vibrio cholerae neuraminidase (VCNA). Compared to the positive controls, all tested polyphenols displayed a weak inhibition of the viral enzyme but similar or even higher potency on the bacterial neuraminidase. Structure–activity relationship analyses revealed the presence of galloyl groups and the hydroxylation pattern of the flavan skeleton to be crucial for inhibitory activity. The combination of zanamivir and EPs® 7630 (root extract of Pelargonium sidoides) showed synergistic inhibitory effects on the bacterial neuraminidase. Co-crystal structures of VCNA with oseltamivir carboxylate and zanamivir provided insight into bacterial versus viral enzyme-inhibitor interactions. The current data clearly indicate that inhibitor potency strongly depends on the biological origin of the enzyme and that results are not readily transferable. The therapeutic relevance of our findings is briefly discussed

Repression of Transcriptional Activity of C/EBPα by E2F-Dimerization Partner Complexes▿†

The transcription factor CCAAT/enhancer-binding protein α (C/EBPα) coordinates proliferation arrest and the differentiation of myeloid progenitors, adipocytes, hepatocytes, keratinocytes, and cells of the lung and placenta. C/EBPα transactivates lineage-specific differentiation genes and inhibits proliferation by repressing E2F-regulated genes. The myeloproliferative C/EBPα BRM2 mutant serves as a paradigm for recurrent human C-terminal bZIP C/EBPα mutations that are involved in acute myeloid leukemogenesis. BRM2 fails to repress E2F and to induce adipogenesis and granulopoiesis. The data presented here show that, independently of pocket proteins, C/EBPα interacts with the dimerization partner (DP) of E2F and that C/EBPα-E2F/DP interaction prevents both binding of C/EBPα to its cognate sites on DNA and transactivation of C/EBP target genes. The BRM2 mutant, in addition, exhibits enhanced interaction with E2F-DP and reduced affinity toward DNA and yet retains transactivation potential and differentiation competence that becomes exposed when E2F/DP levels are low. Our data suggest a tripartite balance between C/EBPα, E2F/DP, and pocket proteins in the control of proliferation, differentiation, and tumorigenesis

Structural basis for molecular recognition and presentation of histone H3 By WDR5

Histone methylation at specific lysine residues brings about various downstream events that are mediated by different effector proteins. The WD40 domain of WDR5 represents a new class of histone methyl-lysine recognition domains that is important for recruiting H3K4 methyltransferases to K4-dimethylated histone H3 tail as well as for global and gene-specific K4 trimethylation. Here we report the crystal structures of full-length WDR5, WDR5Δ23 and its complexes with unmodified, mono-, di- and trimethylated histone H3K4 peptides. The structures reveal that WDR5 is able to bind all of these histone H3 peptides, but only H3K4me2 peptide forms extra interactions with WDR5 by use of both water-mediated hydrogen bonding and the altered hydrophilicity of the modified lysine 4. We propose a mechanism for the involvement of WDR5 in binding and presenting histone H3K4 for further methylation as a component of MLL complexes

Screening by social workers in medical patients with risk of post-acute care needs ::a stepped wedge cluster randomized trial

Background : Elderly patients often need post-acute care after hospital discharge. Involvement of social workers can positively affect the discharge planning process. Aim : To investigate the effect of screening patients at risk for post-acute care needs by social workers on time with respect to social workers’ notification, length of stay and delays in discharge compared to usual care. Methods : Cluster randomized stepped wedge trial design for five clusters (wards) and two steps (control to intervention) was used. A total of 400 patients (200 per period) with high risk of post-acute care needs (defined as Post-Acute Care Discharge score, PACD ≥ 7) were included. Social workers performed a screening to decide about self-referral to their services (intervention period), which was compared to a highly structured standard SW notification by physicians and nurses (control period). A Generalized Estimating Equations model adjusted the clustering and baseline differences. Results : A total of 139 patients were referred to social services (intervention: n = 76; control: n = 63). Time to social workers’ notification was significantly shorter in the intervention period when adjusted for all the differences in baseline (Mdn 1.2 vs 1.7, Beta = -0.73, 95%-CI 1.39 to -0.09). Both the length of stay and the delayed discharge time in nights showed no significant differences (Mdn 10.0 vs 9.1, Beta = -0.12, 95%-CI 0.46 to .22 nights 95%-CI, resp. Mdn 0.0 vs 0.0, Beta = .1 1, 95%-CI -0.64 to 0.86). Conclusion : Screening speeded up social workers’ notification but did not accelerate the discharge processes. The screening by social workers might show process improvement in settings with less structured discharge planningHintergrund: Ältere Patienten benötigen nach dem Spitalaufenthalt oft post-akute Versorgungsangebote, die zu verlängerten Spitalaufenthalten führen. Ein früherer Einbezug von Sozialarbeitern vermag die Austrittsplanung zu verbessern. Ziel: Es wurde untersucht, ob ein durch Sozialarbeiter durchgeführtes Screening von medizinischen Patienten, die ein Risiko für einen post-akuten Nachsorgebedarf aufweisen, im Vergleich zum Standardprozess Unterschiede beim Zeitpunkt der Sozialdienstanmeldung, der Spitalaufenthaltstage und der Wartezeit zeigt. Methode: Ein cluster-randomisiertes stepped-wedge -Studiendesign für fünf Cluster (Stationen) und zwei Perioden (Kontroll- zu Interventionsperiode) wurde angewendet. Insgesamt wurden 400 männliche und weibliche Patienten (200 pro Periode) mit einem hohen Risiko für einen post-akuten Nachsorgebedarf (PACD-Score ≥7) eingeschlossen. Sozialarbeiter führten ein Screening in der Interventionsperiode durch, um zu entscheiden, ob die Patienten einen post-akuten Nachsorgebedarf haben. Als Kontrolle diente der bisherige Prozess, bei dem Patienten mit einem potenziellen Nachsorgebedarf von der Pflege und der Ärzteschaft gemeldet wurden. Zur Analyse wurde ein Generalized-Estimating-Equations -Modell gerechnet. Resultate: Insgesamt wurden 139 Patienten beim Sozialdienst angemeldet (Intervention: n=76, Kontrolle: n=63). Die Zeit bis zur Sozialdienstanmeldung (Median) war in der Interventionsperiode signifikant kürzer (1.2 vs. 1.7, Beta = 0.73, 95%-KI −1.39 bis −0.09 Nächte), wenn für alle Unterschiede kontrolliert wurde. Die Aufenthaltsdauer (10.0 vs. 9.1, Beta = −0.12, 95%-KI −0.46 bis 0.22 Nächte) und die Wartezeiten (0.0 vs. 0.0, Beta = 0.11, 95%-KI −0.64 bis 0.86 Nächte) zeigten keine Unterschiede. Schlussfolgerung: Das Screening durch Sozialarbeiter verkürzte die Zeit bis zur Anmeldung beim Sozialdienst, beschleunigte aber nicht den Austrittsprozess. Das Screening durch Sozialarbeiter könnte in Spitälern mit geringerer strukturierter Austrittsplanung positive Effekte aufzeigen

Screening by Social Workers in Medical Patients with Risk of Post-Acute Care Needs: A Stepped Wedge Cluster Randomized Trial / Evaluation eines Screenings durch Sozialarbeiter bei medizinischen Patienten mit einem Risiko für post-akuten Nachsorgebedarf: eine stepped wedge clusterrandomisierte Studie

Elderly patients often need post-acute care after hospital discharge. Involvement of social workers can positively affect the discharge planning process