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BackgroundAchieving timely accrual into clinical research studies remains a challenge for clinical translational research. We developed an evaluation measure, the Accrual Index (AI), normalized for sample size and study duration, using data from the protocol and study management databases. We applied the AI retrospectively and prospectively to assess its utility. MethodsAccrual Target, Projected Time to Accrual Completion (PTAC), Evaluable Subjects, Dates of Recruitment Initiation, Analysis, and Completion were defined. AI is (% Accrual Target accrued/% PTAC elapsed). Changes to recruitment practices were described, and data extracted from study management databases. ResultsDecember 2014 (or final) AI was analyzed for 101 studies initiating recruitment from 2007 to 2014. Median AI was 1 for protocols initiating recruitment in 2011, 2013, and 2014. The AI varied widely for studies pre-2013. Studies with AI > 4 utilized convenience samples for recruitment. Data-justified PTAC was refined in 2013-2014 after which the AI range narrowed. Protocol characteristics were not associated with study AI. ConclusionProtocol AI reflects the relative agreement between accrual feasibility assessment (PTAC), and accrual performance, and is affected by recruitment practices. The AI may be useful in managing accountability, modeling accrual, allocating recruitment resources, and testing innovations in recruitment practices.

The Mediator complex orchestrates multiple transcription factors with the Pol II apparatus for precise transcriptional control. However, its interplay with the surrounding chromatin remains poorly understood. Here, we analyze differential histone modifications between WT and MED23(-/-) (KO) cells and identify H2B mono-ubiquitination at lysine 120 (H2Bub) as a MED23-dependent histone modification. Using tandem affinity purification and mass spectrometry, we find that MED23 associates with the RNF20/40 complex, the enzyme for H2Bub, and show that this association is critical for the recruitment of RNF20/40 to chromatin. In a cell-free system, Mediator directly and substantially increases H2Bub on recombinant chromatin through its cooperation with RNF20/40 and the PAF complex. Integrative genome-wide analyses show that MED23 depletion specifically reduces H2Bub on a subset of MED23-controlled genes. Importantly, MED23-coupled H2Bub levels are oppositely regulated during myogenesis and lung carcinogenesis. In sum, these results establish a mechanistic link between the Mediator complex and a critical chromatin modification in coordinating transcription with cell growth and differentiation.

Objectives: To measure plasma nucleosome levels and expression of toll-like receptors (TLRs) in a pilot cohort of patients with severe acute kidney injury (AKI) within a randomised controlled trial of continuous venovenous haemofiltration with high cut-off filters (CVVH-HCO) v standard filters (CVVH-std). Methods: We measured plasma nucleosome levels using the Cell Death Detection ELISA PLUS (10X) assay kit. We analysed plasma levels for correlation with disease severity and compared the effects of CVVH-HCO and CVVH-std on plasma nucleosome levels over the first 72 hours. We studied cell surface TLR expression on CD14-positive monocytes in a subcohort of CVVH-HCO patients. Results: We did not detect nucleosomes in normal human plasma, but found elevated nucleosome levels in patients with severe AKI. Nucleosome levels at randomisation correlated weakly with Acute Physiology and Chronic Health Evaluation Ill scores (Pearson rho =0.475, P=0.016). Treatment with CVVH-HCO or CVVH-std had no effect on nucleosome levels over 72 hours. The mean fluorescence intensity (MFI) ratios of TLR2 and TLR4 expression were elevated throughout the 72-hour period (range for TLR2, 0.97-3.98; range for TLR4, 0.91-10.18) and did not appear to decrease as a result of treatment with CVVH-HCO. Conclusions: Nucleosome concentration was elevated in the plasma of patients with severe AKI and mildly correlated with disease severity, but was not affected by treatment with CVVH-HCO or CVVH-std. Similarly, levels of TLR2 and TLR4 expression did not decrease over time during CVVH-HCO treatment.

As a consequence of excessive antibiotic therapies in hospitalized patients, Clostridium difficile, a Gram-positive anaerobic spore-forming intestinal pathogen, is the leading cause of hospital-acquired diarrhea and colitis. Drug treatments for these diseases are often complicated by antibiotic-resistant strains and a high frequency of treatment failures and relapse; therefore, novel nonantibiotic approaches may prove to be more effective. In this study, we recombinantly expressed a prophage lysin identified from a C. difficile strain, CD630, which we named PlyCD. PlyCD was found to have lytic activity against specific C. difficile strains. However, the recombinantly expressed catalytic domain of this protein, PlyCD(1-174), displayed significantly greater lytic activity (>4-log kill) and a broader lytic spectrum against C. difficile strains while still retaining a high degree of specificity toward C. difficile versus commensal clostridia and other bacterial species. Our data also indicated that noneffective doses of vancomycin and PlyCD(1-174) when combined in vitro could be significantly more bactericidal against C. difficile. In an ex vivo treatment model of mouse colon infection, we found that PlyCD(1-174) functioned in the presence of intestinal contents, significantly decreasing colonizing C. difficile compared to controls. Together, these data suggest that PlyCD(1-174) has potential as a novel therapeutic for clinical application against C. difficile infection, either alone or in combination with other preexisting treatments to improve their efficacy.

Huntington's Disease (HD) is a neurodegenerative disorder that results from the abnormal expansion of poly-glutamine (polyQ) repeats in the Huntingtin (HTT) gene. Although HTT has been linked to a variety of cellular events, it is still not clear what the physiological functions of the protein are. Because of its critical role during mouse embryonic mouse development, we investigated the functions of Htt during early Xenopus embryogenesis. We find that reduction of Htt levels affects cilia polarity and function and causes whole body paralysis. Moreover, Htt loss of function leads to abnormal development of trigeminal and motor neurons. Interestingly, these phenotypes are partially rescued by either wild-type or expanded HTT. These results show that the Htt activity is required for normal embryonic development, and highlight the usefulness of the Xeno pus system for investigating proteins involved in human diseases. (C) 2015 Elsevier Inc. All rights reserved.

Trypanosoma brucei, the causative agent of African sleeping sickness, is transmitted to its mammalian host by the tsetse. In the fly, the parasite's surface is covered with invariant procyclin, while in the mammal it resides extracellularly in its bloodstream form (BF) and is densely covered with highly immunogenic Variant Surface Glycoprotein (VSG). In the BF, the parasite varies this highly immunogenic surface VSG using a repertoire of similar to 2500 distinct VSG genes. Recent reports in mammalian systems point to a role for histone acetyl-lysine recognizing bromodomain proteins in the maintenance of stem cell fate, leading us to hypothesize that bromodomain proteins may maintain the BF cell fate in trypanosomes. Using small-molecule inhibitors and genetic mutants for individual bromodomain proteins, we performed RNA-seq experiments that revealed changes in the transcriptome similar to those seen in cells differentiating from the BF to the insect stage. This was recapitulated at the protein level by the appearance of insect-stage proteins on the cell surface. Furthermore, bromodomain inhibition disrupts two major BF-specific immune evasion mechanisms that trypanosomes harness to evade mammalian host antibody responses. First, monoallelic expression of the antigenically varied VSG is disrupted. Second, rapid internalization of antibodies bound to VSG on the surface of the trypanosome is blocked. Thus, our studies reveal a role for trypanosome bromodomain proteins in maintaining bloodstream stage identity and immune evasion. Importantly, bromodomain inhibition leads to a decrease in virulence in a mouse model of infection, establishing these proteins as potential therapeutic drug targets for trypanosomiasis. Our 1.25A resolution crystal structure of a trypanosome bromodomain in complex with I-BET151 reveals a novel binding mode of the inhibitor, which serves as a promising starting point for rational drug design.

Recent studies have identified molecular pathways driving forgetting and supported the notion that forgetting is a biologically active process. The circuit mechanisms of forgetting, however, remain largely unknown. Here we report two sets of Drosophila neurons that account for the rapid forgetting of early olfactory aversive memory. We show that inactivating these neurons inhibits memory decay without altering learning, whereas activating them promotes forgetting. These neurons, including a cluster of dopaminergic neurons ( PAM-beta'1) and a pair of glutamatergic neurons (MBON-gamma 4>gamma 1 gamma 2), terminate in distinct subdomains in the mushroom body and represent parallel neural pathways for regulating forgetting. Interestingly, although activity of these neurons is required for memory decay over time, they are not required for acute forgetting during reversal learning. Our results thus not only establish the presence of multiple neural pathways for forgetting in Drosophila but also suggest the existence of diverse circuit mechanisms of forgetting in different contexts.

Crystallography of the cores of phosphotyrosine-activated dimers of STAT1 (132-713) and STAT3 (127-722) bound to a similar double-stranded deoxyoligonucleotide established the domain structure of the STATs and the structural basis for activation through tyrosine phosphorylation and dimerization. We reported earlier that mutants in the linker domain of STAT1 that connect the DNA-binding domain and SH2 domain can prevent transcriptional activation. Because of the pervasive importance of persistently activated STAT3 in many human cancers and the difficulty of finding useful drug candidates aimed at disrupting the pY interchange in active STAT3 dimers, we have examined effects of an array of mutants in the STAT3 linker domain. We have found several STAT3 linker domain mutants to have profound effects of inhibiting STAT3 transcriptional activation. From these results, we propose (i) there is definite functional interaction of the linker both with the DNA binding domain and with the SH2 domain, and (ii) these putative contacts provide potential new targets for small molecule-induced pSTAT3 inhibition.

The key problem in human infectious diseases was posed at the turn of the 20th century: their pathogenesis. For almost any given virus, bacterium, fungus, or parasite, life-threatening clinical disease develops in only a small minority of infected individuals. Solving this infection enigma is important clinically, for diagnosis, prognosis, prevention, and treatment. Some microbes will inevitably remain refractory to, or escape vaccination, or chemotherapy, or both. The solution also is important biologically, because the emergence and evolution of eukaryotes alongside more rapidly evolving prokaryotes, archaea, and viruses posed immunological challenges of an ecological and evolutionary nature. We need to study these challenges in natural, as opposed to experimental, conditions, and also at the molecular and cellular levels. According to the human genetic theory of infectious diseases, inborn variants underlie life-threatening infectious diseases. Here I review the history of the field of human genetics of infectious diseases from the turn of the 19th century to the second half of the 20th century. This paper thus sets the scene, providing the background information required to understand and appreciate the more recently described monogenic forms of resistance or predisposition to specific infections discussed in a second paper in this issue.