The role of telomere damage in cardiomyocyte ageing

PhD ThesisCellular senescence is often defined as an irreversible cell cycle arrest of mitotic cells, however post-mitotic cells, including adipocytes and neurones, have also been shown to display senescent-like characteristics, such as elevated SA-β-Gal activity and increased production of pro-inflammatory cytokines, in response to persistent DNA damage. Our group have shown that a persistent DDR can occur at telomeres independently of length. We investigated the possibility of telomere dysfunction being associated with senescence in a non-rapidly dividing cell type, which is not subject to repeated end-replication problem-associated telomere shortening. We show that telomere damage can be induced in cardiomyocyte cell lines with X-irradiation or oxidative stress in the absence of cell division, with live-cell imaging revealing the presence of persistent DNA damage foci. Endonuclease-mediated telomere-specific double-strand DNA breaks trigger a senescent-like phenotype in cardiomyocytes in vitro, including elevated SA-β-Gal activity, p21 expression, hypertrophy and decrease of proliferation marker Ki-67. We observed an age-dependent increase in telomere dysfunction in both murine and human cardiomyocytes, occurring independently of telomere length. Furthermore, murine cardiomyocytes in vivo are associated with numerous markers of senescence, such as p15, p16 and p21 elevation, along with increased TGF-β expression and increased prevalence of senescence-associated distension of satellites. Increased oxidative stress via MnSOD-/+, Catalase-/-, or MAO-A overexpression (resulting in excess H2O2 production), can drive telomere dysfunction in murine cardiomyocytes in vivo, which correlates with a decrease in heart function, both of which can be rescued with anti-oxidant supplementation. Finally, we show that rapamycin, a drug shown to increase lifespan and delay age-related diseases in numerous organisms, can attenuate the accumulation of TAF in murine cardiomyocytes in vivo, and is associated with a decrease in senescence markers. Our data provide evidence that telomere dysfunction occurs independently of length in cardiomyocytes, and is associated with a senescent-like phenotype

Justice for the Rich: Have Changes to the Way Criminal Legal Aid is Awarded Undermined Access to Justice?

This article explores the effect that austerity-oriented public policy has had on access to justice in England and Wales, specifically in regard to the way in which legal aid is administered in criminal cases following the implementation of the Legal Aid, Sentencing and Punishment of Offenders Act 2012. The purpose of this paper is to explore the view, now, that only those with the means to fund their own legal representation are recipients of ‘true’ justice. While others, who would have previously relied on legal aid to pay for representation, are now having to represent themselves in court

The MSSM Spectrum from (0,2)-Deformations of the Heterotic Standard Embedding

We construct supersymmetric compactifications of E_8 \times E_8 heterotic string theory which realise exactly the massless spectrum of the Minimal Supersymmetric Standard Model (MSSM) at low energies. The starting point is the standard embedding on a Calabi-Yau threefold which has Hodge numbers (h^11,h^21) = (1,4) and fundamental group Z_12, which gives an E_6 grand unified theory with three net chiral generations. The gauge symmetry is then broken to that of the standard model by a combination of discrete Wilson lines and continuous deformation of the gauge bundle. On eight distinct branches of the moduli space, we find stable bundles with appropriate cohomology groups to give exactly the massless spectrum of the MSSM.Comment: 37 pages including appendice

Exploration of pathomechanisms triggered by a single-nucleotide polymorphism in titin\u27s I-band: the cardiomyopathy-linked mutation T2580I

Missense single-nucleotide polymorphisms (mSNPs) in titin are emerging as a main causative factor of heart failure. However, distinguishing between benign and disease-causing mSNPs is a substantial challenge. Here, we research the question of whether a single mSNP in a generic domain of titin can affect heart function as a whole and, if so, how. For this, we studied the mSNP T2850I, seemingly linked to arrhythmogenic right ventricular cardiomyopathy (ARVC). We used structural biology, computational simulations and transgenic muscle in vivo methods to track the effect of the mutation from the molecular to the organismal level. The data show that the T2850I exchange is compatible with the domain three-dimensional fold, but that it strongly destabilizes it. Further, it induces a change in the conformational dynamics of the titin chain that alters its reactivity, causing the formation of aberrant interactions in the sarcomere. Echocardiography of knock-in mice indicated a mild diastolic dysfunction arising from increased myocardial stiffness. In conclusion, our data provide evidence that single mSNPs in titin\u27s I-band can alter overall muscle behaviour. Our suggested mechanisms of disease are the development of non-native sarcomeric interactions and titin instability leading to a reduced I-band compliance. However, understanding the T2850I-induced ARVC pathology mechanistically remains a complex problem and will require a deeper understanding of the sarcomeric context of the titin region affected

Multiple emergences of genetically diverse amphibian-infecting chytrids include a globalized hypervirulent recombinant lineage

Batrachochytriumdendrobatidis (Bd) is a globally ubiquitous fungal infection that has emerged to become a primary driver of amphibian biodiversity loss. Despite widespread effort to understand the emergence of this panzootic, the origins of the infection, its patterns of global spread, and principle mode of evolution remain largely unknown. Using comparative population genomics, we discovered three deeply diverged lineages of Bd associated with amphibians. Two of these lineages were found in multiple continents and are associated with known introductions by the amphibian trade.We found that isolates belonging to one clade, the global panzootic lineage (BdGPL) have emerged across at least five continents during the 20th century and are associated with the onset of epizootics in North America, Central America, the Caribbean, Australia, and Europe. The two newly identified divergent lineages, Cape lineage (BdCAPE) and Swiss lineage (BdCH), were found to differ in morphological traits when compared against one another and BdGPL, and we show that BdGPL is hypervirulent. BdGPL uniquely bears the hallmarks of genomic recombination, manifested as extensive intergenomic phylogenetic conflict and patchily distributed heterozygosity. Wepostulate that contact between previously genetically isolated allopatric populations of Bd may have allowed recombination to occur, resulting in the generation, spread, and invasion of the hypervirulent BdGPL leading to contemporary disease-driven losses in amphibian biodiversity.Peer Reviewe

On the Use of Carbon Cables from Plastic Solvent Combinations of Polystyrene and Toluene in Carbon Nanotube Synthesis

For every three people on the planet, there are approximately two Tonnes (Te) of plastic waste. We show that carbon recovery from polystyrene (PS) plastic is enhanced by the coaddition of solvents to grow carbon nanotubes (CNTs) by liquid injection chemical vapour deposition. Polystyrene was loaded up to 4 wt% in toluene and heated to 780 °C in the presence of a ferrocene catalyst and a hydrogen/argon carrier gas at a 1:19 ratio. High resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and Raman spectroscopy were used to identify multiwalled carbon nanotubes (MWCNTs). The PS addition in the range from 0 to 4 wt% showed improved quality and CNT homogeneity; Raman “Graphitic/Defective” (G/D) values increased from 1.9 to 2.3; mean CNT diameters increased from 43.0 to 49.2 nm; and maximum CNT yield increased from 11.37% to 14.31%. Since both the CNT diameters and the percentage yield increased following the addition of polystyrene, we conclude that carbon from PS contributes to the carbon within the MWCNTs. The electrical contact resistance of acid-washed Bucky papers produced from each loading ranged from 2.2 to 4.4 Ohm, with no direct correlation to PS loading. Due to this narrow range, materials with different loadings were mixed to create the six wires of an Ethernet cable and tested using iPerf3; the cable achieved up- and down- link speeds of ~99.5 Mbps, i.e., comparable to Cu wire with the same dimensions (~99.5 Mbps). The lifecycle assessment (LCA) of CNT wire production was compared to copper wire production for a use case in a Boeing 747-400 over the lifespan of the aircraft. Due to their lightweight nature, the CNT wires decreased the CO2 footprint by 21 kTonnes (kTe) over the aircraft’s lifespan.We would like to thank Keysight Technologies for the use of a test model of the B2900A SMU. We would like to acknowledge the assistance provided by Swansea University College of Engineering AIM Facility. We would like to thank TRIMTABS Ltd. for purchasing equipment required for making ethernet cables. Thanks to Swansea Employability Academy (SEA) for the summer placements scheme. Thanks to the Swansea University Texas Strategic Partnership. R.E.P. acknowledges his work was associated with the IMPACT operation. We acknowledge pixabay for use of imagery in the graphical abstract (https://pixabay.com/vectors/airplane-boeing-747-transport-48 11157/ (accessed on 1 December 2021))

Vertical consolidation and financial sustainability: evidence from English local government

Proponents of the vertical consolidation of lower-tier units into a smaller number of single-tier local governments suggest that it improves the financial sustainability of governments by generating economies of scale and scope. However, critics suggest that such structural change is beset with disruptive and unanticipated costs that outweigh any potential efficiency savings. I investigate the validity of these contrasting arguments by analysing the expenditure and fiscal health of English county councils before and after the consolidation of the lower-tier units within several counties that took place in 2009. Levels of financial sustainability are modelled using a difference-in-difference estimator for the years 2003–2012. The results suggest that in the short run the consolidated governments have been able to realize administrative economies, but their fiscal health has weakened. These findings appear to be robust to the possibility of selection effects. Theoretical and practical implications are discussed

The TRIM-NHL protein NHL-2 is a Novel Co-Factor of the CSR-1 and HRDE-1 22G-RNA Pathways [preprint]

Proper regulation of germline gene expression is essential for fertility and maintaining species integrity. In the C. elegans germline, a diverse repertoire of regulatory pathways promote the expression of endogenous germline genes and limit the expression of deleterious transcripts to maintain genome homeostasis. Here we show that the conserved TRIM-NHL protein, NHL-2, plays an essential role in the C. elegans germline, modulating germline chromatin and meiotic chromosome organization. We uncover a role for NHL-2 as a co-factor in both positively (CSR-1) and negatively (HRDE-1) acting germline 22G-small RNA pathways and the somatic nuclear RNAi pathway. Furthermore, we demonstrate that NHL-2 is a bona fide RNA binding protein and, along with RNA-seq data point to a small RNA independent role for NHL-2 in regulating transcripts at the level of RNA stability. Collectively, our data implicate NHL-2 as an essential hub of gene regulatory activity in both the germline and soma