Signatures of TOP1 transcription-associated mutagenesis in cancer and germline.

The mutational landscape is shaped by many processes. Genic regions are vulnerable to mutation but are preferentially protected by transcription-coupled repair1. In microorganisms, transcription has been demonstrated to be mutagenic2,3; however, the impact of transcription-associated mutagenesis remains to be established in higher eukaryotes4. Here we show that ID4-a cancer insertion-deletion (indel) mutation signature of unknown aetiology5 characterized by short (2 to 5 base pair) deletions -is due to a transcription-associated mutagenesis process. We demonstrate that defective ribonucleotide excision repair in mammals is associated with the ID4 signature, with mutations occurring at a TNT sequence motif, implicating topoisomerase 1 (TOP1) activity at sites of genome-embedded ribonucleotides as a mechanistic basis. Such TOP1-mediated deletions occur somatically in cancer, and the ID-TOP1 signature is also found in physiological settings, contributing to genic de novo indel mutations in the germline. Thus, although topoisomerases protect against genome instability by relieving topological stress6, their activity may also be an important source of mutations in the human genome.

PRIM1 deficiency causes a distinctive primordial dwarfism syndrome.

DNA replication is fundamental for cell proliferation in all organisms. Nonetheless, components of the replisome have been implicated in human disease, and here we report PRIM1 encoding the catalytic subunit of DNA primase as a novel disease gene. Using a variant classification agnostic approach, biallelic mutations in PRIM1 were identified in five individuals. PRIM1 protein levels were markedly reduced in patient cells, accompanied by replication fork asymmetry, increased interorigin distances, replication stress, and prolonged S-phase duration. Consequently, cell proliferation was markedly impaired, explaining the patients' extreme growth failure. Notably, phenotypic features distinct from those previously reported with DNA polymerase genes were evident, highlighting differing developmental requirements for this core replisome component that warrant future investigation.

Mutations in genes encoding condensin complex proteins cause microcephaly through decatenation failure at mitosis.

Compaction of chromosomes is essential for accurate segregation of the genome during mitosis. In vertebrates, two condensin complexes ensure timely chromosome condensation, sister chromatid disentanglement, and maintenance of mitotic chromosome structure. Here, we report that biallelic mutations in NCAPD2, NCAPH, or NCAPD3, encoding subunits of these complexes, cause microcephaly. In addition, hypomorphic Ncaph2 mice have significantly reduced brain size, with frequent anaphase chromatin bridge formation observed in apical neural progenitors during neurogenesis. Such DNA bridges also arise in condensin-deficient patient cells, where they are the consequence of failed sister chromatid disentanglement during chromosome compaction. This results in chromosome segregation errors, leading to micronucleus formation and increased aneuploidy in daughter cells. These findings establish "condensinopathies" as microcephalic disorders, with decatenation failure as an additional disease mechanism for microcephaly, implicating mitotic chromosome condensation as a key process ensuring mammalian cerebral cortex size.

cGAS surveillance of micronuclei links genome instability to innate immunity.

DNA is strictly compartmentalized within the nucleus to prevent autoimmunity; despite this, cyclic GMP-AMP synthase (cGAS), a cytosolic sensor of double-stranded DNA, is activated in autoinflammatory disorders and by DNA damage. Precisely how cellular DNA gains access to the cytoplasm remains to be determined. Here, we report that cGAS localizes to micronuclei arising from genome instability in a mouse model of monogenic autoinflammation, after exogenous DNA damage and spontaneously in human cancer cells. Such micronuclei occur after mis-segregation of DNA during cell division and consist of chromatin surrounded by its own nuclear membrane. Breakdown of the micronuclear envelope, a process associated with chromothripsis, leads to rapid accumulation of cGAS, providing a mechanism by which self-DNA becomes exposed to the cytosol. cGAS is activated by chromatin, and consistent with a mitotic origin, micronuclei formation and the proinflammatory response following DNA damage are cell-cycle dependent. By combining live-cell laser microdissection with single cell transcriptomics, we establish that interferon-stimulated gene expression is induced in micronucleated cells. We therefore conclude that micronuclei represent an important source of immunostimulatory DNA. As micronuclei formed from lagging chromosomes also activate this pathway, recognition of micronuclei by cGAS may act as a cell-intrinsic immune surveillance mechanism that detects a range of neoplasia-inducing processes.

Supporting farmer wellbeing: exploring a potential role for farm advisory staff.

INTRODUCTION: Farmers in Ireland experience poor health outcomes and are considered 'hard to reach'. Agricultural advisors ('advisors') are uniquely positioned to support and signpost farmers on health issues. This paper explores the acceptability and terms of reference of a potential health role for advisors, and offers key recommendations for developing a bespoke farmers' health training programme. METHODS: Following ethical approval, eleven focus groups (n=26 female, n=35 male, age-range 20s-70s) were conducted with farmers (n=4), advisors (n=4), farming organisations (n=2) and farmers' 'significant others' (n=1). Utilizing Thematic Content Analysis, transcripts were coded iteratively and emerging themes were grouped into primary and subthemes. RESULTS: Our analysis identified three themes. 'Scope and acceptability of a potential health role for advisors' examines how participants envision and are receptive to such a role. 'Roles, responsibilities and boundaries' considers both a health promotion and 'health connector' advisory role - normalising health conversations and signposting farmers to services/supports. Finally, 'trouble-shooting potential obstacles to advisors assuming a health role' reflects on the barriers that may impede advisors capacity or potential to have a broader health role. DISCUSSION: Within the context of the stress process theory, findings provide unique insights into how advisory can mediate stress and contribute to farmers' health and wellbeing. Finally, findings have important implications for potentially extending the reach of training to other aspects of farming support services (eg agri-banking, agri-business, veterinary services etc.), as well as serving as a springboard for the development of similar initiatives in other jurisdictions.

Barriers and facilitators to implementing community-based physical activity interventions: a qualitative systematic review.

BACKGROUND: Over the past decade several physical activity (PA) interventions have been shown to be efficacious in a controlled research setting, however there is a continued lack of evidence for how to successfully implement these PA interventions in real-world settings such as the community. This review aims to explore the barriers and facilitators that affect the implementation of community-based PA interventions and make recommendations to improve implementation from the included studies. METHODS: A systematic literature search of EBSCOhost, Scopus, PUBMED and Web of Science was conducted to identify articles that reported qualitative data on the implementation factors of community-based interventions where PA was a primary outcome. Data were extracted using the Consolidated Framework for Implementation Research (CFIR) as a guide. Implementation factors and recommendations were then mapped onto the 5 domains of the CFIR and synthesised thematically. RESULTS: From 495 articles, a total of 13 eligible studies were identified, with 6 studies using a mixed methods approach, and 7 reporting qualitative methods only. There were 82 implementation factors identified, including 37 barriers and 45 facilitators, and a further 26 recommendations from the papers across all 5 domains of the CFIR. More barriers than facilitators were identified within the CFIR domain inner setting, in contrast to all other domains where facilitator numbers outweighed barriers. CONCLUSIONS: This review identified many facilitators and barriers of implementing physical activity interventions in the community. A key finding of this review was the impact of implementation strategies on successful implementation of community PA interventions. From the evidence, it was clear that many barriers to implementation could have been negated or reduced by an implementation plan in which several strategies are embedded. The findings of this review also suggest more attention to individual' skills and involvement is needed to improve self-efficacy and knowledge. The role of individuals across all organisational levels, from providers to leaders, can impact on the implementation of an intervention and its success. TRIAL REGISTRATION: PROSPERO - CRD42020153821 .

Economic evaluation of 'Men on the Move', a 'real world' community-based physical activity programme for men.

BACKGROUND: Physical activity (PA) interventions capable of producing health benefits cost effectively are a public health priority across the Western world. 'Men on the Move' (MOM), a community-based PA intervention for men, demonstrated significant health benefits up to 52-weeks (W) post-baseline. This article details the economic evaluation of MOM with a view to determining its cost-effectiveness as a public health intervention to be rolled out nationally in Ireland. METHODS: Cost-effectiveness was determined by comparing the costs (direct and indirect) of the programme to its benefits, which were captured as the impact on quality-adjusted life-years (QALYs). For the benefits, cost-utility analysis was conducted by retrospectively adapting various health-related measures of participants to generate health states using Brazier et al.'s (2002) short form-6D algorithm. This in turn allowed for 'utility measures' to be generated, from which QALYs were derived. RESULTS: Findings show MOM to be cost-effective in supporting an 'at risk' cohort of men achieves significant improvements in aerobic fitness, weight loss and waist reduction. The total cost per participant (€125.82 for each of the 501 intervention participants), the QALYs gained (11.98 post-12-W intervention, or 5.3% health improvement per participant) and estimated QALYs ratio costs of €3723 represents a cost-effective improvement when compared to known QALY guidelines. CONCLUSIONS: The analysis shows that the cost per QALY achieved by MOM is significantly less than the existing benchmarks of £20 000 and €45 000 in the UK and Ireland respectively, demonstrating MOM to be cost-effective.

Ribonuclease H2 mutations induce a cGAS/STING-dependent innate immune response.

Aicardi-Goutières syndrome (AGS) provides a monogenic model of nucleic acid-mediated inflammation relevant to the pathogenesis of systemic autoimmunity. Mutations that impair ribonuclease (RNase) H2 enzyme function are the most frequent cause of this autoinflammatory disorder of childhood and are also associated with systemic lupus erythematosus. Reduced processing of eitherRNA:DNAhybrid or genome-embedded ribonucleotide substrates is thought to lead to activation of a yet undefined nucleic acid-sensing pathway. Here, we establishRnaseh2b(A174T/A174T)knock-in mice as a subclinical model of disease, identifying significant interferon-stimulated gene (ISG) transcript upregulation that recapitulates theISGsignature seen inAGSpatients. The inflammatory response is dependent on the nucleic acid sensor cyclicGMP-AMPsynthase (cGAS) and its adaptorSTINGand is associated with reduced cellular ribonucleotide excision repair activity and increasedDNAdamage. This suggests thatcGAS/STINGis a key nucleic acid-sensing pathway relevant toAGS, providing additional insight into disease pathogenesis relevant to the development of therapeutics for this childhood-onset interferonopathy and adult systemic autoimmune disorders.

Recruiting men from across the socioeconomic spectrum via GP registers and community outreach to a weight management feasibility randomised controlled trial.

BACKGROUND: Men, particularly those living in disadvantaged areas, are less likely to participate in weight management programmes than women despite similar levels of excess weight. Little is known about how best to recruit men to weight management interventions. This paper describes patient and public involvement in pre-trial decisions relevant to recruitment and aims to report on recruitment to the subsequent men-only weight management feasibility trial, including the: i) acceptability and feasibility of recruitment; and ii) baseline sample characteristics by recruitment strategy. METHODS: Men with BMI ≥30 kg/m2 and/or waist circumference ≥ 40 in. were recruited to the feasibility trial via two strategies; community outreach (venue information stands and word of mouth) and GP letters, targeting disadvantaged areas. Recruitment activities (e.g. letters sent, researcher venue hours) were recorded systematically, and baseline characteristics questionnaire data collated. Qualitative interviews (n = 50) were conducted three months post-recruitment. Analyses and reporting followed a complementary mixed methods approach. RESULTS: 105 men were recruited within four months (community n = 60, GP letter n = 45). Community outreach took 2.3 recruiter hours per participant and GP letters had an opt-in rate of 10.2% (n = 90/879). More men were interested than could be accommodated. Most participants (60%) lived in more disadvantaged areas. Compared to community outreach, men recruited via GP letters were older (mean = 57 vs 48 years); more likely to report an obesity-related co-morbidity (87% vs 44%); and less educated (no formal qualifications, 32% vs 10%, degree educated 11% vs 41%). Recruitment strategies were acceptable, a sensitive approach and trusting relationships with recruiters valued, and the 'catchy' study name drew attention. CONCLUSIONS: Targeted community outreach and GP letters were acceptable strategies that successfully recruited participants to a men-only weight management feasibility trial. Both strategies engaged men from disadvantaged areas, a typically underserved population. Using two recruitment strategies produced samples with different health risk profiles, which could add value to research where either primary or secondary prevention is of interest. Further work is required to examine how these strategies could be implemented and sustained in practice. TRIAL REGISTRATION: ClinicalTrials.gov: NCT03040518 , 2nd February 2017.