Characteristics of patients initiated on edoxaban in Europe: baseline data from edoxaban treatment in routine clinical practice for patients with atrial fibrillation (AF) in Europe (ETNA-AF-Europe)

Background Non-vitamin K antagonist (VKA) oral anticoagulants (NOACs) have substantially improved anticoagulation therapy for prevention of stroke and systemic embolism in patients with atrial fibrillation (AF). The available routine care data have demonstrated the safety of different NOACs; however, such data for edoxaban are scarce. Here, we report baseline characteristics of 13,638 edoxaban-treated patients with AF enrolled between November 2016 and February 2018. Methods ETNA-AF-Europe is a multinational, multi-centre, post-authorisation, observational study conducted in 825 sites in 10 European countries. Patients will be followed up for four years. Results Overall, 13,980 patients were enrolled of which 342 patients were excluded from the analysis. Mean patient age was 73.6 years with an average creatinine clearance of 69.4 mL/min. 56.6% were male. The calculated CHA2DS2-VASc and HAS-BLED mean scores were 3.1 and 2.6, respectively. Overall, 3.3, 14.6 and 82.0% of patients had low (CHA2DS2-VASc = 0), intermediate (CHA2DS2-VASc = 1) and high (CHA2DS2-VASc≥2) risks of stroke, respectively. High-risk patients (those with prior stroke, prior major bleeding, prior intracranial bleed or CHA2DS2-VASc ≥4) comprised 38.4% of the overall population. For 75.1% of patients edoxaban was their first anticoagulant prescription, whilst 16.9% switched from a VKA and 8.0% from another NOAC. A total of 23.4% of patients in ETNA-AF-Europe received the reduced dose of edoxaban 30 mg. Overall, 83.8% of patients received an edoxaban dose in line with the criteria outlined in the label. Conclusion Edoxaban was predominantly initiated in older, often anticoagulation-naïve, unselected European patients with AF, with a good overall adherence to the approved label. Trial registration NCT02944019; Date of registration: October 24, 2016

A genome-wide screening uncovers the role of CCAR2 as an antagonist of DNA end resection

There are two major and alternative pathways to repair DNA double-strand breaks: non-homologous end-joining and homologous recombination. Here we identify and characterize novel factors involved in choosing between these pathways; in this study we took advantage of the SeeSaw Reporter, in which the repair of double-strand breaks by homology-independent or -dependent mechanisms is distinguished by the accumulation of green or red fluorescence, respectively. Using a genome-wide human esiRNA (endoribonuclease- prepared siRNA) library, we isolate genes that control the recombination/endjoining ratio. Here we report that two distinct sets of genes are involved in the control of the balance between NHEJ and HR: those that are required to facilitate recombination and those that favour NHEJ. This last category includes CCAR2/DBC1, which we show inhibits recombination by limiting the initiation and the extent of DNA end resection, thereby acting as an antagonist of CtIP

Characteristics of patients initiated on edoxaban in Europe:baseline data from edoxaban treatment in routine clinical practice for patients with atrial fibrillation (AF) in Europe (ETNA-AF-Europe)

Background: Non-vitamin K antagonist (VKA) oral anticoagulants (NOACs) have substantially improved anticoagulation therapy for prevention of stroke and systemic embolism in patients with atrial fibrillation (AF). The available routine care data have demonstrated the safety of different NOACs; however, such data for edoxaban are scarce. Here, we report baseline characteristics of 13,638 edoxaban-treated patients with AF enrolled between November 2016 and February 2018. Methods: ETNA-AF-Europe is a multinational, multi-centre, post-authorisation, observational study conducted in 825 sites in 10 European countries. Patients will be followed up for four years. Results: Overall, 13,980 patients were enrolled of which 342 patients were excluded from the analysis. Mean patient age was 73.6 years with an average creatinine clearance of 69.4 mL/min. 56.6% were male. The calculated CHA2DS2-VASc and HAS-BLED mean scores were 3.1 and 2.6, respectively. Overall, 3.3, 14.6 and 82.0% of patients had low (CHA2DS2-VASc = 0), intermediate (CHA2DS2-VASc = 1) and high (CHA2DS2-VASc≥2) risks of stroke, respectively. High-risk patients (those with prior stroke, prior major bleeding, prior intracranial bleed or CHA2DS2-VASc ≥4) comprised 38.4% of the overall population. For 75.1% of patients edoxaban was their first anticoagulant prescription, whilst 16.9% switched from a VKA and 8.0% from another NOAC. A total of 23.4% of patients in ETNA-AF-Europe received the reduced dose of edoxaban 30 mg. Overall, 83.8% of patients received an edoxaban dose in line with the criteria outlined in the label. Conclusion: Edoxaban was predominantly initiated in older, often anticoagulation-naïve, unselected European patients with AF, with a good overall adherence to the approved label. Trial registration: NCT02944019; Date of registration: October 24, 2016

Rif1 maintains telomeres and mediates DNA repair by encasing DNA ends

In yeast, Rif1 is part of the telosome, where it inhibits telomerase and checkpoint signaling at chromosome ends. In mammalian cells, Rif1 is not telomeric, but it suppresses DNA end resection at chromosomal breaks, promoting repair by nonhomologous end joining (NHEJ). Here, we describe crystal structures for the uncharacterized and conserved ∼125-kDa N-terminal domain of Rif1 from Saccharomyces cerevisiae (Rif1-NTD), revealing an α-helical fold shaped like a shepherd's crook. We identify a high-affinity DNA-binding site in the Rif1-NTD that fully encases DNA as a head-to-tail dimer. Engagement of the Rif1-NTD with telomeres proved essential for checkpoint control and telomere length regulation. Unexpectedly, Rif1-NTD also promoted NHEJ at DNA breaks in yeast, revealing a conserved role of Rif1 in DNA repair. We propose that tight associations between the Rif1-NTD and DNA gate access of processing factors to DNA ends, enabling Rif1 to mediate diverse telomere maintenance and DNA repair functions

A Fine-Structure Map of Spontaneous Mitotic Crossovers in the Yeast Saccharomyces cerevisiae

Homologous recombination is an important mechanism for the repair of DNA damage in mitotically dividing cells. Mitotic crossovers between homologues with heterozygous alleles can produce two homozygous daughter cells (loss of heterozygosity), whereas crossovers between repeated genes on non-homologous chromosomes can result in translocations. Using a genetic system that allows selection of daughter cells that contain the reciprocal products of mitotic crossing over, we mapped crossovers and gene conversion events at a resolution of about 4 kb in a 120-kb region of chromosome V of Saccharomyces cerevisiae. The gene conversion tracts associated with mitotic crossovers are much longer (averaging about 12 kb) than the conversion tracts associated with meiotic recombination and are non-randomly distributed along the chromosome. In addition, about 40% of the conversion events have patterns of marker segregation that are most simply explained as reflecting the repair of a chromosome that was broken in G1 of the cell cycle

Drosha drives the formation of DNA:RNA hybrids around DNA break sites to facilitate DNA repair

The error-free and efficient repair of DNA double-stranded breaks (DSBs) is extremely important for cell survival. RNA has been implicated in the resolution of DNA damage but the mechanism remains poorly understood. Here, we show that miRNA biogenesis enzymes, Drosha and Dicer, control the recruitment of repair factors from multiple pathways to sites of damage. Depletion of Drosha significantly reduces DNA repair by both homologous recombination (HR) and non-homologous end joining (NHEJ). Drosha is required within minutes of break induction, suggesting a central and early role for RNA processing in DNA repair. Sequencing of DNA:RNA hybrids reveals RNA invasion around DNA break sites in a Drosha-dependent manner. Removal of the RNA component of these structures results in impaired repair. These results show how RNA can be a direct and critical mediator of DNA damage repair in human cells

Molecular mechanisms and cellular functions of cGAS-STING signalling

The cGAS–STING signalling axis, comprising the synthase for the second messenger cyclic GMP–AMP (cGAS) and the cyclic GMP–AMP receptor stimulator of interferon genes (STING), detects pathogenic DNA to trigger an innate immune reaction involving a strong type I interferon response against microbial infections. Notably however, besides sensing microbial DNA, the DNA sensor cGAS can also be activated by endogenous DNA, including extranuclear chromatin resulting from genotoxic stress and DNA released from mitochondria, placing cGAS–STING as an important axis in autoimmunity, sterile inflammatory responses and cellular senescence. Initial models assumed that co-localization of cGAS and DNA in the cytosol defines the specificity of the pathway for non-self, but recent work revealed that cGAS is also present in the nucleus and at the plasma membrane, and such subcellular compartmentalization was linked to signalling specificity of cGAS. Further confounding the simple view of cGAS–STING signalling as a response mechanism to infectious agents, both cGAS and STING were shown to have additional functions, independent of interferon response. These involve non-catalytic roles of cGAS in regulating DNA repair and signalling via STING to NF-κB and MAPK as well as STING-mediated induction of autophagy and lysosome- dependent cell death. We have also learnt that cGAS dimers can multimerize and undergo liquid–liquid phase separation to form biomolecular condensates that could importantly regulate cGAS activation. Here, we review the molecular mechanisms and cellular functions underlying cGAS–STING activation and signalling, particularly highlighting the newly emerging diversity of this signalling pathway and discussing how the specificity towards normal, damage-induced and infection-associated DNA could be achieved