Regulating the levels of key factors in cell cycle and DNA repair: New pathways revealed by lamins

Spatial and temporal organization of the genome represents an additional step in the regulation of nuclear functions. The nuclear lamina, a polymeric meshwork formed by lamins (A/C and B type) and lamin-associated proteins, plays a key role in the maintenance of genome localization, structure and function. Specifically, mutations in the LMNA gene encoding lamins A/C or changes in its expression, either upregulation or silencing, are associated with defects in DNA replication, transcription and repair, as well as alterations in epigenetic modifications of chromatin. These data, together with the fact that defects in A-type lamins are associated with a whole variety of degenerative disorders, premature aging syndromes and cancer, support the notion that these proteins operate as caretakers of the genome. However, our understanding of their functions is limited due to the lack of well-defined mechanisms behind the genomic instability observed in lamin-related diseases. Here, we summarize our recent discovery of new pathways that are affected by the loss of A-type lamins. In particular, we found that A-type lamins control transcription and degradation of proteins with key roles in cell cycle regulation and DNA double-strand breaks (DSBs) repair by nonhomologous end-joining (NHEJ) and homologous-recombination (HR). Importantly, the proteins regulated by A-type lamins—Rb family members, 53BP1, BRCA1 and RAD51— exert tumor suppressor functions, with their loss being associated with cancer susceptibility. Moreover, our studies revealed novel pathways that contribute to genomic instability and that can be activated in disease states independent of the status of A-type lamins

Siting prisons, sighting communities: geographies of objection in a planning process

This paper reviews the planning process for a Scottish prison located near a former mining village. Analysing the letters of objection submitted by residents offers an opportunity to explore local views about prison and community and to relate these to the unique social and spatial history of the area. The planning process itself structured how residents were able to express themselves and defined what counted as a relevant objection. After deconstructing this process, the paper then restores and uses as a framework for analysis three geographies of objection stripped from local responses to the development proposal: the emotional, temporal, and spatial. Emotional expressions of objection added intensity and gave meaning to claims about the historical decline of the region and also conveyed a deep sense of the proposed building site as a lived space. Particular grounds of opposition—over fear of strangers, the fragility of a local orchid, and the pollution from mining—provide an opportunity to explore the complex nature of place meaning and community identity, ultimately leading to a conclusion that the meaning of place is always in flux. The paper argues that Simmel’s classic concept of the stranger, as the outsider who comes to stay, offers a useful analytic in understanding how the quality of proximal remoteness that prisons and other unwanted developments constitute participates in a constantly evolving sense of the local

Intranasal administration of RSV antigen-expressing MCMV elicits robust tissue-resident effector and effector memory CD8+ T cells in the lung

Cytomegalovirus vectors are promising delivery vehicles for vaccine strategies that aim to elicit effector CD8+ T cells. To determine how the route of immunization affects CD8+ T cell responses in the lungs of mice vaccinated with a murine cytomegalovirus vector expressing the respiratory syncytial virus matrix (M) protein, we infected CB6F1 mice via the intranasal or intraperitoneal route and evaluated the M-specific CD8+ T cell response at early and late time points. We found that intranasal vaccination generated robust and durable tissue-resident effector and effector memory CD8+ T cell populations that were undetectable after intraperitoneal vaccination. The generation of these antigen-experienced cells by intranasal vaccination resulted in earlier T cell responses, interferon gamma secretion, and viral clearance after respiratory syncytial virus challenge. Collectively, these findings validate a novel approach to vaccination that emphasizes the route of delivery as a key determinant of immune priming at the site of vulnerability

Determinants of boat velocity during a 200 m race in elite Paralympic sprint kayakers

This study investigates the relationships between boat velocity, stroke rate and displacement per stroke in Paracanoe 200m Sprint Kayak races. Data were analysed from 646, 200m efforts performed by 13 international Paracanoe athletes between 2017 and 2020 (Male: N= 6, female: N= 7) using boat-based GPS unit (Catapult S5). Significant differences between the Paralympic classifications were observed for boat velocity, stroke rate and displacement per stroke across both genders (p < 0.001) and Paracanoe classification (p < 0.001). Stroke rate was found to be the best predictor of boat velocity across classifications explaining between 13% and 34% of the variation. However, displacement per stroke was found to be more important for males than females potentially due to strength and anthropometric differences. Boat velocity, stroke rate and displacement per stroke values for the final 150m (measured in 50 m splits) indicated evidence for a mix of all-out and positive pacing strategies. The results of this study suggest intricate differences exist in Paracanoe Sprint Kayak based on gender and classification between athletes. This information is useful in the coaching of Paracanoe Sprint Kayak with evidence that physical preparation, training, and race strategy can be individualised to each athlete

Lamin A Δexon9 mutation leads to telomere and chromatin defects but not genomic instability

Over 300 mutations in the LMNA gene, encoding A-type lamins, are associated with 15 human degenerative disorders and premature aging syndromes. Although genomic instability seems to contribute to the pathophysiology of some laminopathies, there is limited information about what mutations cause genomic instability and by which molecular mechanisms. Mouse embryonic fibroblasts depleted of A-type lamins or expressing mutants lacking exons 8–11 (Lmna(Δ8–11/Δ8–11)) exhibit alterations in telomere biology and DNA repair caused by cathepsin L-mediated degradation of 53BP1 and reduced expression of BRCA1 and RAD51. Thus, a region encompassing exons 8–11 seems essential for genome integrity. Given that deletion of lamin A exon 9 in the mouse (Lmna(Δ9/Δ9)) results in a progeria phenotype, we tested if this domain is important for genome integrity. Lmna(Δ9/Δ9) MEFs exhibit telomere shortening and heterochromatin alterations but do not activate cathepsin L-mediated degradation of 53BP1 and maintain expression of BRCA1 and RAD51. Accordingly, Lmna(Δ9/Δ9) MEFs do not present genomic instability, and expression of mutant lamin A Δexon9 in lamin-depleted cells restores DNA repair factors levels and partially rescues nuclear abnormalities. These data reveal that the domain encoded by exon 9 is important to maintain telomere homeostasis and heterochromatin structure but does not play a role in DNA repair, thus pointing to other exons in the lamin A tail as responsible for the genomic instability phenotype in Lmna(Δ8–11/Δ8–11) mice. Our study also suggests that the levels of DNA repair factors 53BP1, BRCA1 and RAD51 could potentially serve as biomarkers to identify laminopathies that present with genomic instability

Abacavir inhibits but does not cause self-reactivity to HLA-B*57:01-restricted EBV specific T cell receptors

Pre-existing pathogen-specific memory T cell responses can contribute to multiple adverse outcomes including autoimmunity and drug hypersensitivity. How the specificity of the T cell receptor (TCR) is subverted or seconded in many of these diseases remains unclear. Here, we apply abacavir hypersensitivity (AHS) as a model to address this question because the disease is linked to memory T cell responses and the HLA risk allele, HLA-B*57:01, and the initiating insult, abacavir, are known. To investigate the role of pathogen-specific TCR specificity in mediating AHS we performed a genome-wide screen for HLA-B*57:01 restricted T cell responses to Epstein-Barr virus (EBV), one of the most prevalent human pathogens. T cell epitope mapping revealed HLA-B*57:01 restricted responses to 17 EBV open reading frames and identified an epitope encoded by EBNA3C. Using these data, we cloned the dominant TCR for EBNA3C and a previously defined epitope within EBNA3B. TCR specificity to each epitope was confirmed, however, cloned TCRs did not cross-react with abacavir plus self-peptide. Nevertheless, abacavir inhibited TCR interactions with their cognate ligands, demonstrating that TCR specificity may be subverted by a drug molecule. These results provide an experimental road map for future studies addressing the heterologous immune responses of TCRs including T cell mediated adverse drug reactions

Disciplinary behaviour management strategies in schools and their impact on student psychosocial outcomes: A systematic review

Background Disciplinary behaviour management strategies are implemented in schools to manage pupil behaviour. There is limited evidence of their intended impact on behaviour but there is growing concern around the potential negative impacts on pupil wellbeing. Methods We carried out a systematic review to examine the impact of these strategies on psychosocial outcomes in pupils (PROSPERO Registration: CRD42021285427). We searched multiple sources and double-screened titles, abstracts, and full texts. Data extraction and risk of bias assessment were done by one reviewer and checked by another. Results were narratively synthesised. Results We included 14 studies, from 5375 citations, assessing temporary suspension (n=10), verbal reprimand (n=2), and mixed strategies (n=2). Depression was the most common outcome (n=7), followed by academic grades (n=4) and behaviour in class (n=4). All except one study were at high risk of bias. We found a recurring pattern in the evidence of disciplinary strategies associated with poor mental wellbeing and behaviour in pupils. The effect on academic attainment was unclear. Conclusions Disciplinary behaviour management strategies may have negative impact on pupil mental wellbeing and class behaviour. These important consequences should be assessed in better designed studies before these strategies are implemented

A dual role for A-type lamins in DNA double-strand break repair

A-type lamins are emerging as regulators of nuclear organization and function. Changes in their expression are associated with cancer and mutations are linked to degenerative diseases—laminopathies. Although a correlation exists between alterations in lamins and genomic instability, the molecular mechanisms remain largely unknown. We previously found that loss of A-type lamins leads to degradation of 53BP1 protein and defective long-range non-homologous end-joining (NHEJ) of dysfunctional telomeres. Here, we determined how loss of A-type lamins affects the repair of short-range DNA double-strand breaks (DSBs) induced by ionizing radiation (IR). We find that lamins deficiency allows activation of the DNA damage response, but compromises the accumulation of 53BP1 at IR-induced foci (IRIF), hindering the fast phase of repair corresponding to classical-NHEJ. Importantly, reconstitution of 53BP1 is sufficient to rescue long-range and short-range NHEJ. Moreover, we demonstrate an unprecedented role for A-type lamins in the maintenance of homologous recombination (HR). Depletion of lamins compromises HR by a mechanism involving transcriptional downregulation of BRCA1 and RAD51 by the repressor complex formed by the Rb family member p130 and E2F4. In line with the DNA repair defects, lamins-deficient cells exhibit increased radiosensitivity. This study demonstrates that A-type lamins promote genomic stability by maintaining the levels of proteins with key roles in DNA DSBs repair by NHEJ and HR. Our results suggest that silencing of A-type lamins by DNA methylation in some cancers could contribute to the genomic instability that drives malignancy. In addition, lamins-deficient tumor cells could represent a good target for radiation therapy

Impact assessment of onchocerciasis through lymphatic filariasis transmission assessment surveys using Ov-16 rapid diagnostic tests in Sierra Leone

Background: Onchocerciasis is endemic in 14 of Sierra Leone's 16 districts with high prevalence (47–88.5%) according to skin snips at baseline. After 11 rounds of mass treatment with ivermectin with good coverage, an impact assessment was conducted in 2017 to assess the progress towards eliminating onchocerciasis in the country. Methods: A cluster survey was conducted, either integrated with lymphatic filariasis (LF) transmission assessment survey (TAS) or standalone with the LF TAS sampling strategy in 12 (now 14) endemic districts. Finger prick blood samples of randomly selected children in Grades 1–4 were tested in the field using SD Bioline Onchocerciasis IgG4 rapid tests. Results: In total, 17,402 children aged 4–19 years in 177 schools were tested, and data from 17,364 children aged 4–14 years (14,230 children aged 5–9 years) were analyzed. Three hundred forty-six children were confirmed positive for Ov-16 IgG4 antibodies, a prevalence of 2.0% (95% CI 1.8–2.2%) in children aged 4–14 years with prevalence increasing with age. Prevalence in boys (2.4%; 95% CI 2.1–2.7%) was higher than in girls (1.6%; 95% CI 1.4–1.9%). There was a trend of continued reduction from baseline to 2010. Using data from children aged 5–9 years, overall prevalence was 1.7% (95% CI 1.5–1.9%). The site prevalence ranged from 0 to 33.3% (median prevalence = 0.0%): &lt; 2% in 127 schools, 2 to &lt; 5% in 34 schools and ≥ 5% in 16 schools. There was a significant difference in average prevalence between districts. Using spatial analysis, the Ov-16 IgG4 antibody prevalence was predicted to be &lt; 2% in coastal areas and in large parts of Koinadugu, Bombali and Tonkolili Districts, while high prevalence (&gt; 5%) was predicted in some focal areas, centered in Karene, Kailahun and Moyamba/Tonkolili. Conclusions:Low Ov-16 IgG4 antibody prevalence was shown in most areas across Sierra Leone. In particular, low seroprevalence in children aged 5–9 years suggests that the infection was reduced to a low level after 11 rounds of treatment intervention. Sierra Leone has made major progress towards elimination of onchocerciasis. However, attention must be paid to those high prevalence focal areas. Graphical Abstract: (Figure presented.)</p