Cytokinin response factor 6 represses cytokinin-associated genes during oxidative stress

Cytokinin is a phytohormone that is well known for its roles in numerous plant growth and developmental processes, yet it has also been linked to abiotic stress response in a less defined manner. Arabidopsis (Arabidopsis thaliana) Cytokinin Response Factor 6 (CRF6) is a cytokinin-responsive AP2/ERF-family transcription factor that, through the cytokinin signaling pathway, plays a key role in the inhibition of dark-induced senescence. CRF6 expression is also induced by oxidative stress, and here we show a novel function for CRF6 in relation to oxidative stress and identify downstream transcriptional targets of CRF6 that are repressed in response to oxidative stress. Analysis of transcriptomic changes in wild-type and crf6 mutant plants treated with H2O2 identified CRF6-dependent differentially expressed transcripts, many of which were repressed rather than induced. Moreover, many repressed genes also show decreased expression in 35S:CRF6 overexpressing plants. Together, these findings suggest that CRF6 functions largely as a transcriptional repressor. Interestingly, among the H2O2 repressed CRF6-dependent transcripts was a set of five genes associated with cytokinin processes: (signaling) ARR6, ARR9, ARR11, (biosynthesis) LOG7, and (transport) ABCG14. We have examined mutants of these cytokinin-associated target genes to reveal novel connections to oxidative stress. Further examination of CRF6-DNA interactions indicated that CRF6 may regulate its targets both directly and indirectly. Together, this shows that CRF6 functions during oxidative stress as a negative regulator to control this cytokinin-associated module of CRF6-dependent genes and establishes a novel connection between cytokinin and oxidative stress response

Alternative mechanism for bacteriophage adsorption to the motile bacterium Caulobacter crescentus

2D and 3D cryo-electron microscopy, together with adsorption kinetics assays of ϕCb13 and ϕCbK phage-infected Caulobacter crescentus, provides insight into the mechanisms of infection. ϕCb13 and ϕCbK actively interact with the flagellum and subsequently attach to receptors on the cell pole. We present evidence that the first interaction of the phage with the bacterial flagellum takes place through a filament on the phage head. This contact with the flagellum facilitates concentration of phage particles around the receptor (i.e., the pilus portals) on the bacterial cell surface, thereby increasing the likelihood of infection. Phage head filaments have not been well characterized and their function is described here. Phage head filaments may systematically underlie the initial interactions of phages with their hosts in other systems and possibly represent a widespread mechanism of efficient phage propagation

Risk Levels and Adverse Clinical Outcomes Among Patients With Nonvalvular Atrial Fibrillation Receiving Oral Anticoagulants

IMPORTANCE: The CHA(2)DS(2)-VASc score (calculated as congestive heart failure, hypertension, age 75 years and older, diabetes, stroke or TIA, vascular disease, age 65 to 74 years, and sex category) is the standard for assessing risk of stroke and systemic embolism and includes age and thromboembolic history. To our knowledge, no studies have comprehensively evaluated safety and effectiveness outcomes among patients with nonvalvular atrial fibrillation receiving oral anticoagulants according to independent, categorical risk strata. OBJECTIVE: To evaluate the incidence of key adverse outcomes among patients with nonvalvular atrial fibrillation receiving oral anticoagulants by CHA(2)DS(2)-VASc risk score range, thromboembolic event history, and age group. DESIGN, SETTING, AND PARTICIPANTS: This cohort study was a retrospective claims data analysis using combined data sets from 5 large health claims databases. Eligible participants were adult patients with nonvalvular atrial fibrillation who initiated oral anticoagulants. Data were analyzed between January 2012 and June 2019. EXPOSURE: Initiation of oral anticoagulants. MAIN OUTCOMES AND MEASURES: We observed clinical outcomes (including stroke or systemic embolism, major bleeding, and a composite outcome) on treatment through study end, censoring for discontinuation of oral anticoagulants, death, and insurance disenrollment. The population was stratified by CHA(2)DS(2)-VASc risk score; history of stroke, systemic embolism, or transient ischemic attack; and age groups. We calculated time to event, incidence rates, and cumulative incidence for outcomes. RESULTS: We identified 1 141 097 patients with nonvalvular atrial fibrillation; the mean (SD) age was 75.0 (10.5) years, 608 127 patients (53.3%) were men, and over 1 million were placed in the 2 highest risk categories (high risk 1, 327 766 participants; high risk 2, 688 449 participants). Deyo-Charlson Comorbidity Index scores ranged progressively alongside CHA(2)DS(2)-VASc risk score strata (mean [SD] scores: low risk, 0.4 [1.0]; high risk 2, 4.1 [2.9]). The crude incidence of stroke and systemic embolism generally progressed alongside risk score strata (low risk, 0.25 events per 100 person-years [95% CI, 0.18-0.34 events]; high risk 2, 3.43 events per 100 person-years [95% CI, 3.06-4.20 events]); patients at the second-highest risk strata with thromboembolic event history had higher stroke incidence vs patients at the highest risk score strata without event history (2.06 events per 100 person-years [95% CI, 2.00-3.12 events] vs 1.18 events per 100 person-years [95% CI, 1.14-1.30 events]). Major bleeding and composite incidence also increased progressively alongside risk score strata (major bleeding: low risk, 0.68 events per 100 person-years [95% CI, 0.56-0.82 events]; high risk 2, 6.29 events per 100 person-years [95% CI, 6.21-6.62 events]; composite incidence: 1.22 events per 100 person-years [95% CI, 1.06-1.41 events]; high risk 2, 10.67 events per 100 person-years [95% CI, 10.26-11.48 events]). The 12-month cumulative incidence proportions for stroke and systemic embolism, major bleeding, and composite outcomes progressed alongside risk score strata (stroke or systemic embolism, 0.30%-1.85%; major bleeding, 0.55%-5.55%; composite, 1.05%-8.23%). Age subgroup analysis followed similar trends. CONCLUSIONS AND RELEVANCE: The observed incidence of stroke or systemic embolism and major bleeding events generally conformed to an expected increasing incidence by risk score, adding insight into the importance of specific risk score range, thromboembolic event history, and age group strata. These results can help inform clinical decision-making, research, and policy

Optimal selection of epitopes for TXP-immunoaffinity mass spectrometry

<p>Abstract</p> <p>Background</p> <p>Mass spectrometry (MS) based protein profiling has become one of the key technologies in biomedical research and biomarker discovery. One bottleneck in MS-based protein analysis is sample preparation and an efficient fractionation step to reduce the complexity of the biological samples, which are too complex to be analyzed directly with MS. Sample preparation strategies that reduce the complexity of tryptic digests by using immunoaffinity based methods have shown to lead to a substantial increase in throughput and sensitivity in the proteomic mass spectrometry approach. The limitation of using such immunoaffinity-based approaches is the availability of the appropriate peptide specific capture antibodies. Recent developments in these approaches, where subsets of peptides with short identical terminal sequences can be enriched using antibodies directed against short terminal epitopes, promise a significant gain in efficiency.</p> <p>Results</p> <p>We show that the minimal set of terminal epitopes for the coverage of a target protein list can be found by the formulation as a set cover problem, preceded by a filtering pipeline for the exclusion of peptides and target epitopes with undesirable properties.</p> <p>Conclusions</p> <p>For small datasets (a few hundred proteins) it is possible to solve the problem to optimality with moderate computational effort using commercial or free solvers. Larger datasets, like full proteomes require the use of heuristics.</p

Effectiveness and safety of oral anticoagulants in non-valvular atrial fibrillation patients with prior bleeding events: a retrospective analysis of administrative claims databases

Introduction There are a paucity of real-world data examining effectiveness and safety of non-vitamin K antagonist oral anticoagulants (NOACs) and warfarin in nonvalvular atrial fibrillation (NVAF) patients with prior bleeding. Methods This retrospective analysis included data from 5 insurance claims databases and included NVAF patients prescribed OACs with prior bleeding. One-to-one propensity score matching was conducted between NOACs and warfarin and between NOACs in each database. Cox proportional hazards models were used to evaluate the risk of stroke/systemic embolism (SE) and MB. Results A total of 244,563 patients (mean age 77; 50% female) with prior bleeding included 55,094 (22.5%) treated with apixaban, 12,500 (5.1%) with dabigatran, 38,246 (15.6%) with rivaroxaban, and 138,723 (56.7%) with warfarin. Apixaban (hazard ratio [HR]: 0.76 [95% CI: 0.70, 0.83]) and rivaroxaban (HR: 0.79 [95% CI: 0.71, 0.87]) had a lower risk of stroke/SE vs. warfarin. Apixaban (HR: 0.67 [95% CI: 0.64, 0.70]) and dabigatran (HR: 0.88 [95% CI: 0.81, 0.96]) had a lower risk of MB vs. warfarin. Apixaban patients had a lower risk of stroke/SE vs. dabigatran (HR: 0.70 [95% CI: 0.57, 0.86]) and rivaroxaban (HR: 0.85 [95% CI: 0.76, 0.96]) and a lower risk of MB than dabigatran (HR: 0.73 [95% CI: 0.67, 0.81]) and rivaroxaban (HR: 0.64 [95% CI: 0.61, 0.68]). Conclusions In this real-world analysis of a large sample of NVAF patients with prior bleeding, NOACs were associated with similar or lower risk of stroke/SE and MB vs. warfarin and variable risk of stroke/SE and MB against each other. Highlights Data on NOAC effectiveness and safety in NVAF patients with prior bleed history are lacking. This study included data on OAC-treated NVAF patients with a history of bleeding. NOACs were associated with similar or lower risk of stroke/SE and MB vs. warfarin. NOACs were associated with variable risk of stroke/SE and MB against each other. This study further demonstrated the effectiveness and safety profile when comparing NOACs to warfarin. The findings could aid to inform the discussion on the benefits and risks in the decision making process for NVAF patients who had a prior bleed

Use of Non-Vitamin K Antagonist Oral Anticoagulants Among Patients with Nonvalvular Atrial Fibrillation and Multimorbidity

Introduction Non-valvular atrial fibrillation (NVAF) is often accompanied by multiple comorbid conditions, which increase the associated risks and complexity of patient management. This study evaluated the risk of stroke/systemic embolism (SE) and major bleeding (MB) among multimorbid patients with NVAF who were prescribed non-vitamin K antagonist oral anticoagulants (NOACs) or warfarin. Methods A retrospective study of patients with NVAF and high multimorbidity who initiated apixaban, dabigatran, rivaroxaban, or warfarin from 1 January 2013 to 30 September 2015 was conducted using five insurance claims databases. Multimorbidity was defined as six or more comorbid conditions, and 1:1 propensity score matching (PSM) was conducted between the NOAC-warfarin and NOAC-NOAC cohorts. Cox proportional hazard models were used to evaluate the hazard ratios of stroke/SE and MB. Results Of the NVAF population (n = 466,991), 33.4% (n = 155,959) had multimorbidity, including 36,921 apixaban, 10,248 dabigatran, 45,509 rivaroxaban, and 63,281 warfarin patients. Compared to warfarin, apixaban and rivaroxaban were associated with a lower risk of stroke/SE (hazard ratio [HR] 0.63, 95% CI 0.54–0.74; HR 0.70, 95% CI 0.64–0.77, respectively). Apixaban and dabigatran were associated with a lower risk of MB (HR 0.61, 95% CI 0.56–0.67; HR 0.75, 95% CI 0.66–0.86, respectively) and rivaroxaban was associated with a higher risk of MB (HR 1.06, 95% CI 1.01–1.12) compared to warfarin. Conclusions Among patients with NVAF and six or more comorbid conditions, NOACs were associated with varying risk of stroke/SE and MB compared to warfarin and to each other. Rather than a “one drug fits all” approach, our results may be useful for appropriate OAC treatment for multimorbid patients

Oral anticoagulants for nonvalvular atrial fibrillation in frail elderly patients: insights from the ARISTOPHANES study

Background Patient frailty amongst patients with nonvalvular atrial fibrillation (NVAF) is associated with adverse health outcomes and increased risk of mortality. Additional evidence is needed to evaluate effective and safe NVAF treatment in this patient population. Objectives This subgroup analysis of the ARISTOPHANES study compared the risk of stroke/systemic embolism (S/SE) and major bleeding (MB) amongst frail NVAF patients prescribed nonvitamin K antagonist oral anticoagulants (NOACs) or warfarin. Methods This comparative retrospective observational study of frail, older NVAF patients who initiated apixaban, dabigatran, rivaroxaban or warfarin from 01JAN2013‐30SEP2015 was conducted using Medicare and 3 US commercial claims databases. To compare each drug, 6 propensity score‐matched (PSM) cohorts were created. Patient cohorts were pooled from 4 databases after PSM. Cox models were used to estimate hazard ratios (HR) of S/SE and MB. Results Amongst NVAF patients, 34% (N = 150 487) met frailty criteria. Apixaban and rivaroxaban were associated with a lower risk of S/SE vs warfarin (apixaban: HR: 0.61, 95% CI: 0.55–0.69; rivaroxaban: HR: 0.79, 95% CI: 0.72–0.87). For MB, apixaban (HR: 0.62, 95% CI: 0.57–0.66) and dabigatran (HR: 0.79, 95% CI: 0.70–0.89) were associated with a lower risk and rivaroxaban (HR: 1.14, 95% CI: 1.08–1.21) was associated with a higher risk vs warfarin. Conclusion Amongst this cohort of frail NVAF patients, NOACs were associated with varying rates of stroke/SE and MB compared with warfarin. Due to the lack of real‐world data regarding OAC treatment in frail patients, these results may inform clinical practice in the treatment of this patient population