154 research outputs found
The RNA-binding protein HuR contributes to neuroinflammation by promoting C-C chemokine receptor 6 (CCR6) expression on Th17 cells.
In both multiple sclerosis and experimental autoimmune encephalomyelitis (EAE), the C-C chemokine receptor 6 (CCR6) is critical for pathogenic T helper 17 (Th17) cell migration to the central nervous system (CNS). Whereas many cytokines and their receptors are potently regulated via post-transcriptional mechanisms in response to various stimuli, how CCR6 expression is post-transcriptionally regulated in Th17 cells is unknown. Here, using RNA-binding protein HuR conditional knock-out (KO) and wild-type (WT) mice, we present evidence that HuR post-transcriptionally regulates CCR6 expression by binding to and stabilizing Ccr6 mRNA and by promoting CCR6 translation. We also found that HuR down-regulates several microRNA expressions, which could target the 3\u27-UTR of Ccr6 mRNA for decay. Accordingly, knock-out of HuR reduced CCR6 expression on Th17 cells and impaired their migration to CNS compared with the response of WT Th17 cells and thereby ameliorated EAE. Together, these findings highlight how HuR contributes to Th17 cell-mediated autoimmune neuroinflammation and support the notion that targeting HuR might be a potential therapeutic intervention for managing autoimmune disorders of the CNS
Approach to Acute Heart Failure in the Emergency Department
Acute heart failure (AHF) patients rarely present complaining of ‘acute heart failure.’ Rather, they initially present to the emergency department (ED) with a myriad of chief complaints, symptoms, and physical exam findings. Such heterogeneity prompts an initially broad differential diagnosis; securing the correct diagnosis can be challenging. Although AHF may be the ultimate diagnosis, the precipitant of decompensation must also be sought and addressed. For those AHF patients who present in respiratory or circulatory failure requiring immediate stabilization, treatment begins even while the diagnosis is uncertain.
The initial diagnostic workup consists of a thorough history and exam (with a particular focus on the cause of decompensation), an EKG, chest X-ray, laboratory testing, and point-of-care ultrasonography performed by a qualified clinician or technologist. We recommend initial treatment be guided by presenting phenotype. Hypertensive patients, particularly those in severe distress and markedly elevated blood pressure, should be treated aggressively with vasodilators, most commonly nitroglycerin. Normotensive patients generally require significant diuresis with intravenous loop diuretics. A small minority of patients present with hypotension or circulatory collapse. These patients are the most difficult to manage and require careful assessment of intra- and extra-vascular volume status. After stabilization, diagnosis, and management, most ED patients with AHF in the United States (US) are admitted. While this is understandable, it may be unnecessary. Ongoing research to improve diagnosis, initial treatment, risk stratification, and disposition may help ease the tremendous public health burden of AHF
Recommended from our members
Identification of a Signature Motif in Target mRNAs of RNA-binding Protein AUF1
The ubiquitous RNA-binding protein AUF1 promotes the degradation of some target mRNAs, but increases the stability and translation of other targets. Here, we isolated AUF1-associated mRNAs by immunoprecipitation of (AUF1–RNA) ribonucleoprotein (RNP) complexes from HeLa cells, identified them using microarrays, and used them to elucidate a signature motif shared among AUF1 target transcripts. The predicted AUF1 motif (29–39 nucleotides) contained 79% As and Us, consistent with the AU-rich sequences of reported AUF1 targets. Importantly, 10 out of 15 previously reported AUF1 target mRNAs contained the AUF1 motif. The predicted interactions between AUF1 and target mRNAs were recapitulated in vitro using biotinylated RNAs. Interestingly, further validation of predicted AUF1 target transcripts revealed that AUF1 associates with both the pre-mRNA and the mature mRNA forms. The consequences of AUF1 binding to 10 predicted target mRNAs were tested by silencing AUF1, which elevated the steady-state levels of only four mRNAs, and by overexpressing AUF1, which also lowered the levels of only four mRNAs. In total, we have identified a signature motif in AUF1 target mRNAs, have found that AUF1 also associates with the corresponding pre-mRNAs, and have discovered that altering AUF1 levels alone only modifies the levels of subsets of target mRNAs
En masse nascent transcription analysis to elucidate regulatory transcription factors
Despite exhaustively informing about steady-state mRNA abundance, DNA microarrays have been used with limited success to identify regulatory transcription factors (TFs). The main limitation of this approach is that altered mRNA stability also strongly governs the patterns of expressed genes. Here, we used nuclear run-on assays and microarrays to systematically interrogate changes in nascent transcription in cells treated with the topoisomerase inhibitor camptothecin (CPT). Analysis of the promoters of coordinately transcribed genes after CPT treatment suggested the involvement of TFs c-Myb and Rfx1. The predicted CPT-dependent associations were subsequently confirmed by chromatin immunoprecipitation assays. Importantly, after RNAi-mediated knockdown of each TF, the CPT-elicited induction of c-Myb- and/or Rfx1-regulated mRNAs was diminished and the overall cellular response was impaired. The strategies described here permit the successful identification of the TFs responsible for implementing adaptive gene expression programs in response to cellular stimulation
Data and safety monitoring in social behavioral intervention trials: the REACH II experience
Background Psychosocial and behavioral interventions trials targeting a broad range of complex social and behavioral problems such as smoking, obesity and family caregiving have proliferated in the past 30 years. At the same time the use of Data and Safety Monitoring Boards (DSMBs) to monitor the progress and quality of intervention trials and the safety of study participants has increased substantially. Most of the existing literature and guidelines for safety monitoring and reporting of adverse events focuses on medical interventions. Consequently, there is little guidance for investigators conducting social and behavior trials.
Purpose This paper summarizes how issues associated with safety monitoring and adverse event reporting were handled in the Resources for Enhancing Alzheimer\u27s Caregiver Health (REACH II) program, a multi-site randomized clinical trial, funded by the National Institutes on Aging (NIA) and the National Institutes of Nursing Research (NINR), that tested the efficacy of a multicomponent social/behavioral intervention for caregivers of persons with Alzheimer\u27s disease.
Methods A task force was formed to define adverse events for the trial and protocols for reporting and resolving events that occurred. The task force conducted a review of existing polices and protocols for data and safety monitoring and adverse event reporting and identified potential risks particular to the study population. An informal survey regarding data and safety monitoring procedures with investigators on psychosocial intervention trials was also conducted.
Results Two categories of events were defined for both caregivers and patients; adverse events and safety alerts. A distinction was also made between events detected at baseline assessment and those detected post-randomization. Standardized protocols were also developed for the reporting and resolution of events that occurred and training of study personnel. Results from the informal survey indicated wide variability in practices for data safety and monitoring across psychosocial intervention trials. Conclusions Overall, the REACH II experience demonstrates that existing guidelines regarding safety monitoring and adverse event reporting pose unique challenges for social/behavioral intervention trials. Challenges encountered in the REACH II program included defining and classifying adverse events, defining resolution of adverse events and attributing causes for events that occurred. These challenges are highlighted and recommendations for addressing them in future studies are discussed
RNA topoisomerase is prevalent in all domains of life and associates with polyribosomes in animals
DNA Topoisomerases are essential to resolve topological problems during DNA metabolism in all species. However, the prevalence and function of RNA topoisomerases remain uncertain. Here, we show that RNA topoisomerase activity is prevalent in Type IA topoisomerases from bacteria, archaea, and eukarya. Moreover, this activity always requires the conserved Type IA core domains and the same catalytic residue used in DNA topoisomerase reaction; however, it does not absolutely require the non-conserved carboxyl-terminal domain (CTD), which is necessary for relaxation reactions of supercoiled DNA. The RNA topoisomerase activity of human Top3β differs from that of Escherichia coli topoisomerase I in that the former but not the latter requires the CTD, indicating that topoisomerases have developed distinct mechanisms during evolution to catalyze RNA topoisomerase reactions. Notably, Top3β proteins from several animals associate with polyribosomes, which are units of mRNA translation, whereas the Top3 homologs from E. coli and yeast lack the association. The Top3β-polyribosome association requires TDRD3, which directly interacts with Top3β and is present in animals but not bacteria or yeast. We propose that RNA topoisomerases arose in the early RNA world, and that they are retained through all domains of DNA-based life, where they mediate mRNA translation as part of polyribosomes in animals
What’s Next for Acute Heart Failure Research?
Each year over one million patients with acute heart failure (AHF) present to a United States emergency department (ED). The vast majority are hospitalized for further management. The length of stay and high postdischarge event rate in this cohort have changed little over the past decade. Therapeutic trials have failed to yield substantive improvement in postdischarge outcomes; subsequently, AHF care has changed little in the past 40 years. Prior research studies have been fragmented as either “inpatient” or “ED-based.” Recognizing the challenges in identification and enrollment of ED patients with AHF, and the lack of robust evidence to guide management, an AHF clinical trials network was developed. This network has demonstrated, through organized collaboration between cardiology and emergency medicine, that many of the hurdles in AHF research can be overcome. The development of a network that supports the collaboration of acute care and HF researchers, combined with the availability of federally funded infrastructure, will facilitate more efficient conduct of both explanatory and pragmatic trials in AHF. Yet many important questions remain, and in this document our group of emergency medicine and cardiology investigators have identified four high-priority research areas
Clinical and Research Considerations for Patients with Hypertensive Acute Heart Failure
Management approaches for patients in the emergency department (ED) who present with acute heart failure (AHF) have largely focused on intravenous diuretics. Yet, the primary pathophysiologic derangement underlying AHF in many patients is not solely volume overload. Patients with hypertensive AHF (H-AHF) represent a clinical phenotype with distinct pathophysiologic mechanisms that result in elevated ventricular filling pressures. To optimize treatment response and minimize adverse events in this subgroup, we propose that clinical management be tailored to a conceptual model of disease based on these mechanisms. This consensus statement reviews the relevant pathophysiology, clinical characteristics, approach to therapy, and considerations for clinical trials in ED patients with H-AHF
- …