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The role of GGT5+ fibroblasts in leukocyte compartmentalisation in the gut and synovium
Get PDFThe spatial organisation of leukocytes within tissues is essential for coordinated immune responses. While stromal cells such as fibroblasts are well known to structure leukocyte niches in secondary lymphoid organs (SLOs), their role in organising immune cells within inflamed non‑lymphoid tissues remains unclear. Building on mechanisms described in germinal centres (GCs), where follicular dendritic cells (FDCs) restrict B cell movement through the GGT5–GGG–P2RY8 axis, this thesis tests the hypothesis that stromal programs, particularly the induction of GGT5 by fibroblasts, establish perivascular confinement zones that spatially position P2RY8⁺ leukocytes within inflamed synovial and intestinal tissues.Analysis of publicly available single-cell RNA-sequencing datasets revealed that GGT5, an enzyme shaping local gradients of the inhibitory ligand GGG, is broadly expressed by stromal cells across multiple inflamed tissues. In most tissues, GGT5 expression is restricted to endothelial cells and pericytes, but in RA synovium it expands beyond vascular rings into neighbouring fibroblasts, whereas in gut it is broadly distributed, forming a perivascular gradient associated with vascular activation. TNFα and NOTCH3 ligands induce GGT5 in synovial fibroblasts, while endothelial‑cell–derived factors stimulate GGT5 in both synovial and intestinal fibroblasts, suggesting that vascular–stromal communication provides an endothelium‑linked cue during inflammation.Functionally, GGG inhibited CXCL12‑ and CXCL13‑directed migration of human tonsil T follicular helper (Tfh) and GC B cells, and Tfh from inflamed gut, consistent with P2RY8‑dependent immobilisation. Pilot live‑imaging provides an analysis framework for quantifying chemotactic index and speed under GGG. As inflammation unfolds, leukocytes infiltrate via blood vessels, triggering neighbouring fibroblasts to upregulate GGT5 expression. This facilitates the establishment of a perivascular confinement zone, wherein GGT5⁺ fibroblasts, through the GGT5–GGG–P2RY8 axis, regulate the motility and positioning of P2RY8⁺ leukocytes, contributing to leukocyte compartmentalisation.Complementary murine colitis and arthritis models probe Ggt5 biology in vivo. However, mice lack P2RY8, limiting direct inference about GGG–P2RY8 signalling. Given that Ggt5 also participates in the leukotriene pathway, in vivo experiments have explored alternative roles for Ggt5 beyond P2RY8 signalling. Together, the data in this thesis supports a model in which endothelial activation and fibroblast GGT5 induction establish perivascular confinement zones that tune leukocyte positioning in IMIDs. These findings motivate the development of tools to map GGG in situ and suggest therapeutic strategies to modulate GGT5 activity to either stabilise protective niches or disperse pathogenic aggregates in RA and IBD
Revisiting the impact of political corruption on environmental policies by using data from 40 countries
Get PDFBackground: Political corruption undermines the effectiveness of environmental governance by eroding institutional capacity, distorting regulatory frameworks, and weakening policy enforcement. This study revisits the relationship between political corruption and environmental policy stringency (EPS), focusing on how corruption influences the strength of environmental regulations across countries and over time. Methods: A cross-national time-series analysis is conducted for 40 countries from 1990 to 2020 using data from the V-Dem Political Corruption Index and the OECD Environmental Policy Stringency Index. The baseline estimation employs a two-way fixed-effects model, complemented by robustness checks using Panel-Corrected Standard Errors (PCSE), Feasible Generalized Least Squares (FGLS), and System Generalized Method of Moments (System GMM). Findings: Results consistently demonstrate that higher political corruption is significantly associated with lower environmental policy stringency. Corruption weakens institutional oversight and enforcement capacity, thereby reducing governments’ ability to implement stringent regulations. Unexpectedly, the negative effect of corruption is more pronounced in developed countries, likely reflecting subtler, institutionalized forms such as regulatory capture and corporate lobbying. Conclusions: While institutional maturity can limit overt corruption, it does not fully shield advanced economies from its environmental consequences. These findings highlight that anti-corruption reforms should be integral to strategies for strengthening environmental governance
Stellar cooling limits on KK gravitons and dark dimensions
Get PDFWe revisit cooling bounds on light Kaluza-Klein (KK) gravitons, as arise in the dark dimension scenario, considering globular clusters, neutron stars, and supernovae. In addition to bremsstrahlung, we account for two novel production channels: resonant mixing with the in-medium photon and a pion-induced process in supernovae. The strongest limits arise from SN 1987A, with the emissivity from the pion process exceeding that from bremsstrahlung by a factor of a few albeit with substantial uncertainties, while resonant production is heavily suppressed. We obtain a bound on the KK mass scale of mKK ≳ 0.6 eV (≳ 500 eV) for 2 (3) extra dimensions, which, having accounted for these previously neglected processes, is broadly compatible with existing analyses. Improved understanding of the properties of pions in supernovae could strengthen these limits to roughly eV (keV). For 1 extra dimension, the bounds are weaker than those from laboratory searches. We also show that constraints from KK graviton decays to Standard Model particles are less stringent than the cooling bounds if there is KK number violation at the level typically assumed in the dark dimension scenario, although these bounds could be strengthened by future observations
Structural mass spectrometry techniques for characterisation of plant and algal proteins
Get PDFSUMMARY: Structural biology can offer valuable insights into the mechanisms and functions of key proteins within plant molecular and cellular systems. However, plant proteins present several specific challenges for structural analysis, including difficulties in expression and purification, significant intrinsic disorder, and extensive post‐translational modification. Structural mass spectrometry (MS) offers a complementary set of tools that can help overcome these obstacles and provide detailed structural and mechanistic information. In this review, we outline the principles and practical applications of the main structural mass spectrometry techniques, namely crosslinking, covalent labelling, hydrogen–deuterium exchange, and both intact (denaturing) and native MS. We also discuss recent case studies where structural MS has offered insight into the architecture, dynamics and interactions of proteins central to plant molecular and cell biology
Intradiscal linezolid (PP353) treatment for chronic low back pain associated with Modic change type 1: an international, first-in-human, randomised, sham procedure-controlled, double-blind, phase 1b clinical trial
Get PDFBackgroundOral amoxicillin reduced pain and disability in patients with chronic Low Back Pain (cLBP) and vertebral endplate bone oedema (Modic changes type 1; MC1) in two randomised controlled trials (RCTs), providing evidence that cLBP with MC1 may be caused by a chronic bacterial infection of the disc. Disc tissue is poorly vascularised, and oral antibiotics will not achieve optimal antibacterial concentration. Linezolid has been formulated for intradiscal administration (PP353) to deliver effective antibacterial therapy while minimising systemic exposure. This trial aimed to establish whether PP353 is safe and has the potential to treat cLBP with MC1 or mixed MC1 and Modic changes type 2 (MC2).MethodsThe trial was a double blind, randomised, sham-procedure controlled phase 1b clinical trial in patients with cLBP of ≥6 months duration and MC1 or mixed MC1 and MC2 at a single lumbar level, aged 18-70 years, average Low Back Pain Numerical Rating Scale (LBP NRS) ≥ 4 on chronic pain medication or ≥ 6 if not, Roland Morris Disability Questionnaire-23 (RMDQ-23) score ≥9, low back pain greater than leg pain, and failure to adequately respond to standard of care. Interactive response technology randomly assigned participants 1:1 to PP353 (2 intradiscal doses) or placebo (2 sham procedures). The primary outcomes were the incidence of adverse events and the change in LBP NRS score at 12 months. Secondary outcomes were change in LBP NRS at intervening timepoints and change in RMDQ-23 and Oswestry Disability Index (ODI) (v2.1) at all timepoints, responder analyses ≥30% and ≥50% change from baseline and characterisation of the pharmacokinetics of two doses of PP353. The trial is registered with ClinicalTrials.gov (NCT04238676) and EudraCT (2018-004488-30), and the Universal Trial Number is U1111-1257-2567.FindingsBetween December, 2021, and December, 2023, 41 participants from sites in the UK, Spain, New Zealand and Denmark were recruited, with 40 participants receiving at least one dose of PP353 (20 participants) or placebo (20 participants) and having at least one post-baseline assessment of efficacy. 29 (72.5%) participants were female. PP353 and the intradiscal procedure were well tolerated, with no severe, life-threatening or disabling adverse events and no overall difference in adverse events from the sham procedure. At 12 months, a statistically significant and clinically meaningful difference between PP353 and placebo in mean group change from baseline in patient-reported pain (LBP NRS -3.36 vs -2.00; 95% CI -0.19, p = 0.028), using a predefined one-sided test, was observed.InterpretationTwo intradiscal administrations of PP353 are well tolerated and could be an effective and minimally invasive, day case therapy for patients with cLBP associated with MC1 or mixed MC1 and MC2.FundingPersica Pharmaceuticals Ltd funded the trial and was responsible for the conceptualisation, overall design, collation of data, decision to publish and the first draft of the manuscript
Opportunities to Improve Nutrition for Patients in Hospital After Discharge From an Intensive Care Unit: A Human Factors Analysis
Get PDFBackground: Nutrition during hospitalisation following critical illness is fundamental to rehabilitation, but provision is often poor. Aim: To analyse the process of delivering nutrition to post‐ICU patients on the ward. Study Design: This work forms part of a mixed methods study. In three representative UK hospitals, we conducted: a structured judgement review (SJR) of 300 patients who died following discharge from ICU; in‐depth reviews of 20 survivors and 20 deaths judged to be ‘probably avoidable’ in the SJR; and interviews with 55 patients, family members and staff about their experiences of post‐ICU ward care. We extracted nutrition provision information from the primary data. Using these data and the Functional Resonance Analysis Method (FRAM), we worked with stakeholders to map the process of delivering enteral feed to patients discharged from ICU to hospital wards. Results: The stakeholder meeting included a dietitian and a medical registrar from two of the three primary data collection sites, two researchers with knowledge of the primary data (with nursing and physiotherapy backgrounds) and a human factors facilitator. The FRAM revealed that providing enteral feeding on the ward is not a linear process, with three clusters of functions delivering distinct steps within the wider process: establishing the need for nasogastric feeding, the nasogastric placement cycle and nasogastric feed delivery. There are multiple points in these processes where failures in multi‐professional teamwork result in the absence of the required steps to move through the processes in a timely manner. In particular, the process for confirming nasogastric tube placement risked system‐related delays to feed administration, significantly affecting the volume of feed delivered to patients. Conclusions: The FRAM identified multiple process problems affecting nutritional support that may have led to profound consequences for post‐ICU patients, with multi‐professional collaboration a key factor for effective delivery of timely enteral nutrition. Relevance to Clinical Practice: Improving collaborative working processes and addressing common nutritional support problems after ICU discharge could improve nutritional delivery and expedite recovery from critical illness. Trial Registration: ISRCTN1465805
2.24Å and 2.13Å structures of divalent anion sodium symporter (DASS) member LaINDY from L. acidophilus reveal highly-coordinated structural waters and a lipid at the dimer interface
Get PDFThe divalent anion sodium symporter (DASS) family are low affinity dicarboxylate phosphate transporters found across all domains of life. The DASS family contains two distinct clades: cotransporters, which utilise a sodium gradient to drive transport across the plasma membrane; and exchangers which utilise dicaboxylate antiport. The cotransporter clade is most well characterised, and contains the human SLC13 family which are involved in the disease pathologies of diabetes, cancer and epilepsy. In contrast, the exchanger clade DASS members are exclusively found exclusively in plants and prokaryotes. Better understanding of the DASS-E clade may have implications for bacterial infections, bioproduction and agriculture. Through the model DASS exchanger LaINDY from Lactobacillus acidophilus this project aims to characterise the substrate binding, and the transport mechanism of the DASS exchangers. Here I present 2.13Å and 2.24Å structures Cryo-EM structures of LaINDY, with the improved resolution revealing highly coordinated waters within the elevator domain that I hypothesise may have functional roles, and a phosphatidyl glycerol molecule modelled at the dimer interface. While the Cryo-EM maps were determined in the presence of ligands, no density was observed in the LaINDY binding site. This is consistent with in vitro binding experiments by tryptophan fluorescence quenching, which revealed LaINDYs low affinity for substrate at pH7.5. Ultimately my results reveal further complexity LaINDYs, transport mechanism, and substrate binding which may apply to the DASS exchanger clade as a whole
Translation, cross-cultural adaptation, and validation of the Caregiver Indirect and Informal Care Cost Assessment Questionnaire for end-of-life care into Spanish
Get PDFOBJECTIVE: This study aims to adapt and validate a Spanish (Argentina) version of the Caregiver Indirect and Informal Care Cost Assessment Questionnaire (CIIQ) to enable the measurement of informal care-related costs in the Argentine context, addressing the current lack of Spanish-language tools for assessing indirect costs. METHOD: The CIIQ was translated, cross-culturally adapted, and validated for the Spanish-Argentine language and culture. Psychometric properties were evaluated in a purposive sample of relatives of patients with advanced chronic disease and limited life expectancy in Argentina. Missing data and internal consistency (Cronbach's α) were assessed, along with discriminant capacity, content, and construct validity. Construct validity was examined through principal component analysis (PCA) and confirmatory factor analysis (CFA). RESULTS: The translation and cultural adaptation process was completed without major difficulties. A total of 154 caregivers completed the baseline questionnaire and 90 completed the follow-up assessment, with missing data remaining below 10% across items. Internal consistency was high for the overall instrument (α = 0.802) and for the unpaid care cost domain (α = 0.866). The productivity loss domain showed moderate reliability (α = 0.362). Low correlations with unrelated domains (ρ < 0.2) supported adequate discriminant validity. PCA identified 2 components - informal care costs (51.5% of explained variance) and productivity loss costs (20.3%) - which were further supported by CFA. SIGNIFICANCE OF RESULTS: The Spanish-Argentine version of the CIIQ is a reliable and culturally appropriate instrument for assessing the economic burden of informal care in Argentina. While the unpaid care items demonstrated strong psychometric performance, productivity-related items may require refinement to improve reliability in future applications
ATTITUDES TO THE LAW IN MENANDER: PAROCHIAL PANHELLENISM AND RADICAL CONSERVATISM
Get PDFThis article examines attitudes to the law in Menander. It argues that the law is given a specifically Athenian context and that it can give us an insight into the concerns and values of the playwright and his society. By analysing the ways in which characters perceive issues of legality, the article stresses the importance of humanity and personal character in the plays’ dramatization of the interface between private lives and public institutions in early Hellenistic Athens. The article highlights how the ambivalence and the multivocality which are inherent in Menander’s dramatic technique allow for varying responses and for the presentation of radical views