Replenishing the malaria drug discovery pipeline: Screening and hit evaluation of the MMV Hit Generation Library 1 (HGL1) against asexual blood stage Plasmodium falciparum, using a nano luciferase reporter read-out.

A central challenge of antimalarial therapy is the emergence of resistance to the components of artemisinin-based combination therapies (ACTs) and the urgent need for new drugs acting through novel mechanism of action. Over the last decade, compounds identified in phenotypic high throughput screens (HTS) have provided the starting point for six candidate drugs currently in the Medicines for Malaria Venture (MMV) clinical development portfolio. However, the published screening data which provided much of the new chemical matter for malaria drug discovery projects have been extensively mined. Here we present a new screening and selection cascade for generation of hit compounds active against the blood stage of Plasmodium falciparum. In addition, we validate our approach by testing a library of 141,786 compounds not reported earlier as being tested against malaria. The Hit Generation Library 1 (HGL1) was designed to maximise the chemical diversity and novelty of compounds with physicochemical properties associated with potential for further development. A robust HTS cascade containing orthogonal efficacy and cytotoxicity assays, including a newly developed and validated nanoluciferase-based assay was used to profile the compounds. 75 compounds (Screening Active hit rate of 0.05%) were identified meeting our stringent selection criteria of potency in drug sensitive (NF54) and drug resistant (Dd2) parasite strains (IC50 ≤ 2 µM), rapid speed of action and cell viability in HepG2 cells (IC50 ≥ 10 µM). Following further profiling, 33 compounds were identified that meet the MMV Confirmed Active profile and are high quality starting points for new antimalarial drug discovery projects.

Preclinical characterization and target validation of the antimalarial pantothenamide MMV693183.

Drug resistance and a dire lack of transmission-blocking antimalarials hamper malaria elimination. Here, we present the pantothenamide MMV693183 as a first-in-class acetyl-CoA synthetase (AcAS) inhibitor to enter preclinical development. Our studies demonstrate attractive drug-like properties and in vivo efficacy in a humanized mouse model of Plasmodium falciparum infection. The compound shows single digit nanomolar in vitro activity against P. falciparum and P. vivax clinical isolates, and potently blocks P. falciparum transmission to Anopheles mosquitoes. Genetic and biochemical studies identify AcAS as the target of the MMV693183-derived antimetabolite, CoA-MMV693183. Pharmacokinetic-pharmacodynamic modelling predict that a single 30 mg oral dose is sufficient to cure a malaria infection in humans. Toxicology studies in rats indicate a > 30-fold safety margin in relation to the predicted human efficacious exposure. In conclusion, MMV693183 represents a promising candidate for further (pre)clinical development with a novel mode of action for treatment of malaria and blocking transmission.

Rehabilitation after paediatric acquired brain injury: Longitudinal change in content and effect on recovery.

AIM: To describe cross-sectional and longitudinal variation in neurorehabilitation content provided to young people after severe paediatric acquired brain injury (pABI) and to relate this to observed functional recovery. METHOD: This was an observational study in a cohort of admissions to a residential neurorehabilitation centre. Recovery was described using the Pediatric Evaluation of Disability - Computer Adaptive Testing instrument. Rehabilitation content was measured using the recently described Paediatric Rehabilitation Ingredients Measure (PRISM) and examined using multidimensional scaling. RESULTS: The PRISM reveals wide variation in rehabilitation content between and during admissions primarily reflecting proportions of child active practice, child emotional support, and other management of body structure and function. Rehabilitation content is predicted by pre-admission recovery, suggesting therapist decisions in designing rehabilitation programmes are shaped by their initial expectations of recovery. However, significant correlations persist between plausibly-related aspects of delivered therapy and observed post-admission recovery after adjusting for such effects. INTERPRETATION: The PRISM approach to the analysis of rehabilitation content shows promise in that it demonstrates significant correlations between plausibly-related aspects of delivered therapy and observed recovery that have been hard to identify with other approaches. However, rigorous, causal analysis will be required to truly understand the contributions of rehabilitation to recovery after pABI. WHAT THIS PAPER ADDS: Rehabilitation content varies widely between, and during, admissions for neurorehabilitation after paediatric acquire brain injury. Strong correlations are seen between plausibly-related aspects of rehabilitation content and observed recovery, though careful interpretation is necessary.

The Nitrobenzoxadiazole Derivative NBDHEX Behaves as Plasmodium falciparum Gametocyte Selective Inhibitor with Malaria Parasite Transmission Blocking Activity.

This work describes the activity of 6-((7-nitrobenzo[c][1,2,5]oxadiazol-4-yl)thio)hexan-1-ol (NBDHEX) and of its newly identified carboxylic acid metabolite on the human malaria parasite Plasmodium falciparum. NBDHEX has been previously identified as a potent cytotoxic agent against murine and human cancer cells as well as towards the protozoan parasite Giardia duodenalis. We show here that NBDHEX is active in vitro against all blood stages of P. falciparum, with the rare feature of killing the parasite stages transmissible to mosquitoes, the gametocytes, with a 4-fold higher potency than that on the pathogenic asexual stages. This activity importantly translates into blocking parasite transmission through the Anopheles vector in mosquito experimental infections. A mass spectrometry analysis identified covalent NBDHEX modifications in specific cysteine residues of five gametocyte proteins, possibly associated with its antiparasitic effect. The carboxylic acid metabolite of NBDHEX retains the gametocyte preferential inhibitory activity of the parent compound, making this novel P. falciparum transmission-blocking chemotype at least as a new tool to uncover biological processes targetable by gametocyte selective drugs. Both NBDHEX and its carboxylic acid metabolite show very limited in vitro cytotoxicity on VERO cells. This result and previous evidence that NBDHEX shows an excellent in vivo safety profile in mice and is orally active against human cancer xenografts make these molecules potential starting points to develop new P. falciparum transmission-blocking agents, enriching the repertoire of drugs needed to eliminate malaria.

Barcoded Asaia bacteria enable mosquito in vivo screens and identify novel systemic insecticides and inhibitors of malaria transmission.

This work addresses the need for new chemical matter in product development for control of pest insects and vector-borne diseases. We present a barcoding strategy that enables phenotypic screens of blood-feeding insects against small molecules in microtiter plate-based arrays and apply this to discovery of novel systemic insecticides and compounds that block malaria parasite development in the mosquito vector. Encoding of the blood meals was achieved through recombinant DNA-tagged Asaia bacteria that successfully colonised Aedes and Anopheles mosquitoes. An arrayed screen of a collection of pesticides showed that chemical classes of avermectins, phenylpyrazoles, and neonicotinoids were enriched for compounds with systemic adulticide activity against Anopheles. Using a luminescent Plasmodium falciparum reporter strain, barcoded screens identified 48 drug-like transmission-blocking compounds from a 400-compound antimicrobial library. The approach significantly increases the throughput in phenotypic screening campaigns using adult insects and identifies novel candidate small molecules for disease control.

The Community Navigator Study: Results from a feasibility randomised controlled trial of a programme to reduce loneliness for people with complex anxiety or depression.

BACKGROUND: Loneliness is common among people with mental health problems and predicts poorer recovery from depression and anxiety. Needs for support with loneliness and social relationships are often under-addressed in mental health services. The Community Navigator programme was designed to reduce loneliness for adults (aged 18 and above) with complex depression or anxiety who were using secondary mental health services. Acceptability and feasibility of the programme and a trial evaluation were tested in a feasibility randomised controlled trial with qualitative evaluation. METHODS: Forty participants with depression or anxiety using secondary mental health services were recruited from mental health services in two London sites and randomised to receive: the Community Navigator programme over six months in addition to routine care (n = 30); or routine care (n = 10). Measures of loneliness, depression, other clinical and social outcomes and service use were collected at baseline and six-months follow-up. Levels of engagement in the programme and rates of trial recruitment and retention were assessed. Programme delivery was assessed through session logs completed by Community Navigators. The acceptability of the programme was explored through qualitative interviews (n = 32) with intervention group participants, their family and friends, programme providers and other involved staff. RESULTS: Forty participants were recruited in four months from 65 eligible potential participants asked. No one withdrew from the trial. Follow-up interviews were completed with 35 participants (88%). Process records indicated the programme was delivered as intended: there was a median of seven meetings with their Community Navigator (of a maximum ten) per treatment group participant. Qualitative interviews indicated good acceptability of the programme to stakeholders, and potential utility in reducing loneliness and depression and anxiety. CONCLUSIONS: A definitive, multi-site randomised controlled trial is recommended to evaluate the effectiveness and cost-effectiveness of the Community Navigator programme for people with complex anxiety and depression in secondary mental health services.

Epigenetic reader complexes of the human malaria parasite, Plasmodium falciparum.

Epigenetic regulatory mechanisms are central to the development and survival of all eukaryotic organisms. These mechanisms critically depend on the marking of chromatin domains with distinctive histone tail modifications (PTMs) and their recognition by effector protein complexes. Here we used quantitative proteomic approaches to unveil interactions between PTMs and associated reader protein complexes of Plasmodium falciparum, a unicellular parasite causing malaria. Histone peptide pull-downs with the most prominent and/or parasite-specific PTMs revealed the binding preference for 14 putative and novel reader proteins. Amongst others, they highlighted the acetylation-level-dependent recruitment of the BDP1/BDP2 complex and identified an PhD-finger protein (PHD 1, PF3D7_1008100) that could mediate a cross-talk between H3K4me2/3 and H3K9ac marks. Tagging and interaction proteomics of 12 identified proteins unveiled the composition of 5 major epigenetic complexes, including the elusive TBP-associated-factor complex as well as two distinct GCN5/ADA2 complexes. Furthermore, it has highlighted a remarkable degree of interaction between these five (sub)complexes. Collectively, this study provides an extensive inventory of PTM-reader interactions and composition of epigenetic complexes. It will not only fuel further explorations of gene regulation amongst ancient eukaryotes, but also provides a stepping stone for exploration of PTM-reader interactions for antimalarial drug development.

An analysis of suicide trends in Scotland 1950-2014: comparison with England & Wales.

BACKGROUND: Scotland has disproportionately high rates of suicide compared with England. An analysis of trends may help reveal whether rates appear driven more by birth cohort, period or age. A 'birth cohort effect' for England & Wales has been previously reported by Gunnell et al. (B J Psych 182:164-70, 2003). This study replicates this analysis for Scotland, makes comparisons between the countries, and provides information on 'vulnerable' cohorts. METHODS: Suicide and corresponding general population data were obtained from the National Records of Scotland, 1950 to 2014. Age and gender specific mortality rates were estimated. Age, period and cohort patterns were explored graphically by trend analysis. RESULTS: A pattern was found whereby successive male birth cohorts born after 1940 experienced higher suicide rates, in increasingly younger age groups, echoing findings reported for England & Wales. Young men (aged 20-39) were found to have a marked and statistically significant increase in suicide between those in the 1960 and 1965 birth cohorts. The 1965 cohort peaked in suicide rate aged 35-39, and the subsequent 1970 cohort peaked even younger, aged 25-29; it is possible that these 1965 and 1970 cohorts are at greater mass vulnerability to suicide than earlier cohorts. This was reflected in data for England & Wales, but to a lesser extent. Suicide rates associated with male birth cohorts subsequent to 1975 were less severe, and not statistically significantly different from earlier cohorts, suggestive of an amelioration of any possible influential 'cohort' effect. Scottish female suicide rates for all age groups converged and stabilised over time. Women have not been as affected as men, with less variation in patterns by different birth cohorts and with a much less convincing corresponding pattern suggestive of a 'cohort' effect. CONCLUSIONS: Trend analysis is useful in identifying 'vulnerable' cohorts, providing opportunities to develop suicide prevention strategies addressing these cohorts as they age.

Malaria parasites possess a telomere repeat-binding protein that shares ancestry with transcription factor IIIA.

Telomere repeat-binding factors (TRFs) are essential components of the molecular machinery that regulates telomere function. TRFs are widely conserved across eukaryotes and bind duplex telomere repeats via a characteristic MYB-type domain. Here, we identified the telomere repeat-binding protein PfTRZ in the malaria parasite Plasmodium falciparum, a member of the Alveolate phylum for which TRFs have not been described so far. PfTRZ lacks an MYB domain and binds telomere repeats via a C2H2-type zinc finger domain instead. In vivo, PfTRZ binds with high specificity to the telomeric tract and to interstitial telomere repeats upstream of subtelomeric virulence genes. Conditional depletion experiments revealed that PfTRZ regulates telomere length homeostasis and is required for efficient cell cycle progression. Intriguingly, we found that PfTRZ also binds to and regulates the expression of 5S rDNA genes. Combined with detailed phylogenetic analyses, our findings identified PfTRZ as a remote functional homologue of the basic transcription factor TFIIIA, which acquired a new function in telomere maintenance early in the apicomplexan lineage. Our work sheds unexpected new light on the evolution of telomere repeat-binding proteins and paves the way for dissecting the presumably divergent mechanisms regulating telomere functionality in one of the most deadly human pathogens.

H3.3 demarcates GC-rich coding and subtelomeric regions and serves as potential memory mark for virulence gene expression in Plasmodium falciparum.

Histones, by packaging and organizing the DNA into chromatin, serve as essential building blocks for eukaryotic life. The basic structure of the chromatin is established by four canonical histones (H2A, H2B, H3 and H4), while histone variants are more commonly utilized to alter the properties of specific chromatin domains. H3.3, a variant of histone H3, was found to have diverse localization patterns and functions across species but has been rather poorly studied in protists. Here we present the first genome-wide analysis of H3.3 in the malaria-causing, apicomplexan parasite, P. falciparum, which revealed a complex occupancy profile consisting of conserved and parasite-specific features. In contrast to other histone variants, PfH3.3 primarily demarcates euchromatic coding and subtelomeric repetitive sequences. Stable occupancy of PfH3.3 in these regions is largely uncoupled from the transcriptional activity and appears to be primarily dependent on the GC-content of the underlying DNA. Importantly, PfH3.3 specifically marks the promoter region of an active and poised, but not inactive antigenic variation (var) gene, thereby potentially contributing to immune evasion. Collectively, our data suggest that PfH3.3, together with other histone variants, indexes the P. falciparum genome to functionally distinct domains and contribute to a key survival strategy of this deadly pathogen.

Adult congenital heart disease interventions: recommendations from a joint working group of the British Congenital Cardiac Association, British Cardiovascular Intervention Society, and the British Cardiovascular Society.

In order to optimise care of the adult patients with complex congenital heart disease, there is a need to develop recommendations for interventions. This document is the work of representatives of the three relevant societies and provides recommendations for institutions and operators performing cardiac interventions in these patients.

Denosumab for the prevention of osteoporotic fractures in post-menopausal women: a NICE single technology appraisal.

The National Institute for Health and Clinical Excellence (NICE) invited the manufacturer of denosumab (Amgen Inc., UK) to submit evidence for the clinical and cost effectiveness of denosumab for the prevention of fragility fractures in post-menopausal women, as part of the Institute's single technology appraisal (STA) process. The University of Aberdeen Health Technology Assessment Group were commissioned to act as the Evidence Review Group (ERG); the role of the ERG being to appraise the manufacturer's submission and to produce an independent report. This article provides a description of the company submission, the ERG review and NICE's subsequent decisions. The manufacturer considered that denosumab would be appropriate for patients unable to take, comply with or tolerate oral bisphosphonates. Comparator treatments selected for the submission were, therefore, 'no treatment', raloxifene, strontium ranelate, intravenous zoledronic acid, intravenous ibandronate and teriparatide. The main effectiveness evidence for denosumab was derived from a large randomized controlled trial comparing denosumab with placebo. Given by subcutaneous injection at 6-monthly intervals for 3 years, denosumab reduced the incidence of hip fracture by 40%, and reduced the incidence of clinical vertebral fracture by 69%. An indirect treatment comparison was used to derive adjusted relative risk (RR) estimates for different types of fracture for each comparator versus placebo. The RRs (95% CI) applied for denosumab were 0.316 (0.208, 0.478) for clinical vertebral fracture, 0.605 (0.373, 0.983) for hip fracture and 0.842 (0.638, 1.110) for wrist fracture. Despite a number of concerns surrounding the methodology of the indirect comparison, the ERG was satisfied with the robustness of the effect estimates. The RR estimates were applied in a good-quality Markov model that took account of drug costs, administration and monitoring costs, costs associated with fractures, and long-term nursing home costs. Utility weights were used to adjust time spent in fracture states, allowing QALYs to be estimated. The base-case analysis was conducted for women aged 70 years with a T-score of -2.5 or less and no prior fracture, and women aged 70 years with a T-score of -2.5 or less with a prior fragility fracture. Subgroup analyses based on T-score and independent clinical risk factors were also undertaken. Applying a willingness-to-pay (WTP) threshold of £30 000 per QALY, the manufacturer's results suggested that denosumab would offer a cost-effective alternative to all treatment comparators for the primary and secondary prevention of fractures. The ERG was concerned about an assumption that denosumab would be administered in general practice at the average cost of two standard GP visits a year. As a result, the ERG requested some further sensitivity analysis and undertook some further modelling, applying an assumption that denosumab would be provided primarily in secondary care. This modification altered the cost effectiveness of denosumab versus 'no treatment' (in women with no prior fragility fracture) and zoledronic acid. The NICE Appraisal Committee concluded that, as a treatment option for the prevention of osteoporotic fractures, denosumab should be recommended only in post-menopausal women at increased risk of fracture who cannot comply with the special instructions for administering oral bisphosphonates, or have an intolerance of, or contraindication to, those treatments. For primary prevention, the Appraisal Committee also stipulated specific levels of fracture risk at which denosumab is recommended.

Reduction in young male suicide in Scotland.

BACKGROUND: Rates of suicide and undetermined death increased rapidly in Scotland in the 1980's and 1990's. The largest increases were in men, with a marked increase in rates in younger age groups. This was associated with an increase in hanging as a method of suicide. National suicide prevention work has identified young men as a priority group. Routinely collected national information suggested a decrease in suicide rates in younger men at the beginning of the 21st century. This study tested whether this was a significant change in trend, and whether it was associated with any change in hanging rates in young men. METHODS: Joinpoint regression was used to estimate annual percentage changes in age-specific rates of suicide and undetermined intent death, and to identify times when the trends changed significantly. Rates of deaths by method in 15 - 29 year old males and females were also examined to assess whether there had been any significant changes in method use in this age group. RESULTS: There was a 42% reduction in rates in 15 - 29 year old men, from 42.5/100,000 in 2000 to 24.5/100,000 in 2004. A joinpoint analysis confirmed that this was a significant change. There was also a significant change in trend in hanging in men in this age group, with a reduction in rates after 2000. No other male age group showed a significant change in trend over the period 1980 - 2004. There was a smaller reduction in suicide rates in women in the 15 - 29 year old age group, with a reduction in hanging from 2002. CONCLUSION: There has been a reduction in suicide rates in men aged 15 - 29 years, and this is associated with a significant reduction in deaths by hanging in this age group. It is not clear whether this is related to a change in method preference, or an overall reduction in suicidal behaviour, and review of self-harm data will be required to investigate this further.