NPM1 directs PIDDosome-dependent caspase-2 activation in the nucleolus

The PIDDosome (PIDD–RAIDD–caspase-2 complex) is considered to be the primary signaling platform for caspase-2 activation in response to genotoxic stress. Yet studies of PIDD-deficient mice show that caspase-2 activation can proceed in the absence of PIDD. Here we show that DNA damage induces the assembly of at least two distinct activation platforms for caspase-2: a cytoplasmic platform that is RAIDD dependent but PIDD independent, and a nucleolar platform that requires both PIDD and RAIDD. Furthermore, the nucleolar phosphoprotein nucleophosmin (NPM1) acts as a scaffold for PIDD and is essential for PIDDosome assembly in the nucleolus after DNA damage. Inhibition of NPM1 impairs caspase-2 processing, apoptosis, and caspase-2–dependent inhibition of cell growth, demonstrating that the NPM1-dependent nucleolar PIDDosome is a key initiator of the caspase-2 activation cascade. Thus we have identified the nucleolus as a novel site for caspase-2 activation and function

Caspase-2-mediated cell death is required for deleting aneuploid cells

Caspase-2, one of the most evolutionarily conserved of the caspase family, has been implicated in maintenance of chromosomal stability and tumour suppression. Caspase-2 deficient (Casp2-/-) mice develop normally but show premature ageing-related traits and when challenged by certain stressors, succumb to enhanced tumour development and aneuploidy. To test how caspase-2 protects against chromosomal instability, we utilized an ex vivo system for aneuploidy where primary splenocytes from Casp2-/- mice were exposed to anti-mitotic drugs and followed up by live cell imaging. Our data show that caspase-2 is required for deleting mitotically aberrant cells. Acute silencing of caspase-2 in cultured human cells recapitulated these results. We further generated Casp2C320S mutant mice to demonstrate that caspase-2 catalytic activity is essential for its function in limiting aneuploidy. Our results provide direct evidence that the apoptotic activity of caspase-2 is necessary for deleting cells with mitotic aberrations to limit aneuploidy.S Dawar, Y Lim, J Puccini, M White, P Thomas, L Bouchier-Hayes, D R Green, L Dorstyn and S Kuma

Genome Sequence of the Saprophyte Leptospira biflexa Provides Insights into the Evolution of Leptospira and the Pathogenesis of Leptospirosis

Leptospira biflexa is a free-living saprophytic spirochete present in aquatic environments. We determined the genome sequence of L. biflexa, making it the first saprophytic Leptospira to be sequenced. The L. biflexa genome has 3,590 protein-coding genes distributed across three circular replicons: the major 3,604 chromosome, a smaller 278-kb replicon that also carries essential genes, and a third 74-kb replicon. Comparative sequence analysis provides evidence that L. biflexa is an excellent model for the study of Leptospira evolution; we conclude that 2052 genes (61%) represent a progenitor genome that existed before divergence of pathogenic and saprophytic Leptospira species. Comparisons of the L. biflexa genome with two pathogenic Leptospira species reveal several major findings. Nearly one-third of the L. biflexa genes are absent in pathogenic Leptospira. We suggest that once incorporated into the L. biflexa genome, laterally transferred DNA undergoes minimal rearrangement due to physical restrictions imposed by high gene density and limited presence of transposable elements. In contrast, the genomes of pathogenic Leptospira species undergo frequent rearrangements, often involving recombination between insertion sequences. Identification of genes common to the two pathogenic species, L. borgpetersenii and L. interrogans, but absent in L. biflexa, is consistent with a role for these genes in pathogenesis. Differences in environmental sensing capacities of L. biflexa, L. borgpetersenii, and L. interrogans suggest a model which postulates that loss of signal transduction functions in L. borgpetersenii has impaired its survival outside a mammalian host, whereas L. interrogans has retained environmental sensory functions that facilitate disease transmission through water

Running With the Ball? Making a Play for Sport Heritage Archives in Higher Education Contexts

For considerable time, academia (in particular, the Humanities) has been in an intellectual, economic and pragmatic par des deux with the culture and arts sector (in this case, heritage, museums and archives). In many ways, given their respective pursuits of scientific enquiry and learning, valuable contribution to a knowledge economy, commitment to public enlightenment, and exploration of critical and creative endeavour, a relationship between the sectors makes sense. Unity notwithstanding, the relationships have become increasingly now influenced by (en)forced contextual constraints (e.g., government policy development and intervention, neoliberal market forces, structural and ideological shifts in funding acquisition and allocation, patronage changes and demands, and/or individual political priorities) (Dubuc 2011; McCall and Gray 2014; Watson 2002). Drawing on education and heritage scholarship, and theoretical frameworks of sport culture spaces (Hardy, Loy and Booth 2009; Phillips 2012; Pinson 2017), this paper examines efforts undertaken at one specific Higher Education establishment in the United Kingdom in which institutional agendas (vis-à-vis historical and cultural foci, encouraging ‘impactful’ academic activity, brand exposure, economic efficiency, and community engagement) have contoured, and become entwined with, an embryonic sport heritage and archive project. Recalling similar arrangements elsewhere (Krüger 2014; Reilly, Clayton and Hughson 2014; Reilly 2015), the aim of this case study is to explore how the wider education and cultural policy context have precipitated an increasingly symbiotic and dependent relationship between university and cultural/arts initiatives. The paper considers how the impetus to develop a sports-based (basketball) heritage archive and study centre reflects the current fragilities of the two sectors, yet, concomitantly, reveals the potentials that might be developed from fostering greater intellectual and pragmatic alliances. The paper concludes by advocating the practical, political and ideological usefulness of network formation, sustainability measures and continued cross-sector dialogue

Investigation of Swedish cases reveals an outbreak of cryptosporidiosis at a Norwegian hotel with possible links to in-house water systems

<p>Abstract</p> <p>Background</p> <p>In March 2007, the Norwegian Institute of Public Health was notified of Swedish individuals diagnosed with cryptosporidiosis after staying at a Norwegian hotel. In Norway, cryptosporidiosis is not reportable, and human infections are rarely diagnosed.</p> <p>Methods</p> <p>A questionnaire on illness and exposure history was e-mailed to seven organised groups who had visited the hotel in March. Cases were defined as persons with diarrhoea for more than two days or laboratory-confirmed cryptosporidiosis during or within two weeks of the hotel visit. The risk factor analysis was restricted to two groups with the highest attack rates (AR) and same hotel stay period. Local food safety authorities conducted environmental investigations.</p> <p>Results</p> <p>In total, 25 diarrhoeal cases (10 laboratory-confirmed) were identified among 89 respondents. Although environmental samples were negative, epidemiological data suggest an association with in-house water consumption. In one group, the AR was higher amongst consumers of water from hotel dispenser (relative risk [RR] = 3.0; 95% confidence interval [CI]: 0.9–9.8), tap water (RR = 2.3; CI: 0.9–5.8), and lower amongst commercial bottled water drinkers (RR = 0.6; CI: 0.4–1.0). Consumption of ice cubes was a risk-factor (RR = 7.1; CI: 1.1–45.7) in the two groups combined.</p> <p>Conclusion</p> <p>This outbreak would probably have remained undetected without the alert from Swedish health authorities, illustrating the difficulties in outbreak detection due to low health care seeking behaviour for diarrhoea and limited parasite diagnostics in Norway. Awareness of cryptosporidiosis should be raised amongst Norwegian medical personnel to improve case and outbreak detection, and possible risks related to in-house water systems should be assessed.</p

Thrombomodulin expression in colorectal carcinoma is protective and correlates with survival

Thrombomodulin (TM) is an endothelial receptor that exhibits anticoagulant, antifibrinolytic and anti-inflammatory activity by inhibiting thrombin and cellular adhesion. In this study, the expression and significance of TM was examined in primary colorectal cancer and its prognostic implications explored. TM immunostaining was performed on formalin-fixed, paraffin-embedded tissue sections, from primary lesions of 200 patients with colorectal carcinoma. Institutional Ethical approval was granted and clinical data retrieved from patients' records. All normal colonic tissue expressed TM on endothelial cells. TM tumour cell expression was demonstrated in 53 (26.5%) cases and 147 (73.5%) showed no neoplastic cell staining. On univariate and multivariate analysis TM expression on tumour cells correlated significantly with tumour stage, differentiation, Jass score and 5 year survival. TM expression decreases as overall stage and tumour size increase (P=0.03). In all, 91% TM positive tumours were well differentiated and 85% of TM negative tumours were poorly differentiated (P<0.01). Five year survival rates of patients with positive and negative TM expression were 71 and 41%, respectively. Survival rate was poorer in those patients who were TM negative compared with those who were positive (P<0.01). A total of 101 (50.5%) of the cases were node negative. In this group, 5 year survival rates of patients with positive and negative TM expression were 87.5 and 37.8%, respectively, demonstrating a poorer survival rate for those who are node negative and TM negative at the time of surgery (P<0.001). This study demonstrates that loss of TM is a key indicator in tumour biology and prognosis

The Molecular Chaperone Hsp90α Is Required for Meiotic Progression of Spermatocytes beyond Pachytene in the Mouse

The molecular chaperone Hsp90 has been found to be essential for viability in all tested eukaryotes, from the budding yeast to Drosophila. In mammals, two genes encode the two highly similar and functionally largely redundant isoforms Hsp90α and Hsp90β. Although they are co-expressed in most if not all cells, their relative levels vary between tissues and during development. Since mouse embryos lacking Hsp90β die at implantation, and despite the fact that Hsp90 inhibitors being tested as anti-cancer agents are relatively well tolerated, the organismic functions of Hsp90 in mammals remain largely unknown. We have generated mouse lines carrying gene trap insertions in the Hsp90α gene to investigate the global functions of this isoform. Surprisingly, mice without Hsp90α are apparently normal, with one major exception. Mutant male mice, whose Hsp90β levels are unchanged, are sterile because of a complete failure to produce sperm. While the development of the male reproductive system appears to be normal, spermatogenesis arrests specifically at the pachytene stage of meiosis I. Over time, the number of spermatocytes and the levels of the meiotic regulators and Hsp90 interactors Hsp70-2, NASP and Cdc2 are reduced. We speculate that Hsp90α may be required to maintain and to activate these regulators and/or to disassemble the synaptonemal complex that holds homologous chromosomes together. The link between fertility and Hsp90 is further supported by our finding that an Hsp90 inhibitor that can cross the blood-testis barrier can partially phenocopy the genetic defects

Evolutionary Dynamics of Human Toll-Like Receptors and Their Different Contributions to Host Defense

Infectious diseases have been paramount among the threats to health and survival throughout human evolutionary history. Natural selection is therefore expected to act strongly on host defense genes, particularly on innate immunity genes whose products mediate the direct interaction between the host and the microbial environment. In insects and mammals, the Toll-like receptors (TLRs) appear to play a major role in initiating innate immune responses against microbes. In humans, however, it has been speculated that the set of TLRs could be redundant for protective immunity. We investigated how natural selection has acted upon human TLRs, as an approach to assess their level of biological redundancy. We sequenced the ten human TLRs in a panel of 158 individuals from various populations worldwide and found that the intracellular TLRs—activated by nucleic acids and particularly specialized in viral recognition—have evolved under strong purifying selection, indicating their essential non-redundant role in host survival. Conversely, the selective constraints on the TLRs expressed on the cell surface—activated by compounds other than nucleic acids—have been much more relaxed, with higher rates of damaging nonsynonymous and stop mutations tolerated, suggesting their higher redundancy. Finally, we tested whether TLRs have experienced spatially-varying selection in human populations and found that the region encompassing TLR10-TLR1-TLR6 has been the target of recent positive selection among non-Africans. Our findings indicate that the different TLRs differ in their immunological redundancy, reflecting their distinct contributions to host defense. The insights gained in this study foster new hypotheses to be tested in clinical and epidemiological genetics of infectious disease