Publications by authors named "Michael Clarkson"

Article Synopsis
  • - Disulfide-constrained peptides (DCPs) are gaining popularity in drug development due to their stability and benefits of both large biologics and small molecules, but traditional chemical synthesis is costly and environmentally damaging.
  • - A new bioproduction platform was introduced for creating DCPs in a cost-effective and eco-friendly way, utilizing bacterial expression and innovative ligation techniques to produce modified versions of the model peptide MK1-3.6.10.
  • - The study also achieved high yields of specifically labeled MK1-3.6.10 and developed a semi-automated workflow for studying DCPs, showing promise for a sustainable approach to DCP discovery that reduces reliance on harmful chemicals and speeds up the process.
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Land-based recirculating aquaculture systems (RAS) have risen in prevalence in recent years for Atlantic salmon production, enabling intensive production which allows increased growth and environmental control, but also having the potential for reducing water use and eutrophication. The Atlantic salmon has an anadromous life history with juvenile stages in freshwater (FW) and on-growing in seawater (SW), enabled by a transformational process known as smoltification. The timing of smoltification and transfer of smolts from FW to SW is critical under commercial production with high mortalities during this period.

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  • Immunosuppressive treatment for rheumatic diseases helps maintain remission but raises infection risk and diminishes response to SARS-CoV-2 vaccination.
  • The study evaluated immune responses to SARS-CoV-2 in two patient groups: one during acute infection and one post-vaccination, comparing results among those exposed to rituximab, other immunosuppressive treatments, and non-immunosuppressed individuals.
  • Results showed that while non-immunosuppressed patients had stronger T cell responses during infection, those on immunosuppression had reduced activation, with rituximab-treated patients showing preserved T cell responses but poor antibody production post-vaccination.
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Antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) is a rare multisystem autoimmune disease. There is a need for interoperable national registries to enable reporting of real-world long-term outcomes and their predictors in AAV. The Irish National Rare Kidney Disease (RKD) registry was founded in 2012.

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Background: A rapid, accurate method to identify and to age-grade mosquito populations would be a major advance in predicting the risk of pathogen transmission and evaluating the public health impact of vector control interventions. Whilst other spectrometric or transcriptomic methods show promise, current approaches rely on challenging morphological techniques or simple binary classifications that cannot identify the subset of the population old enough to be infectious. In this study, the ability of rapid evaporative ionisation mass spectrometry (REIMS) to identify the species and age of mosquitoes reared in the laboratory and derived from the wild was investigated.

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A pulldown using a biotinylated natural product of interest in the 17β-hydroxywithanolide (17-BHW) class, physachenolide C (PCC), identified the bromodomain and extra-terminal domain (BET) family of proteins (BRD2, BRD3, and BRD4), readers of acetyl-lysine modifications and regulators of gene transcription, as potential cellular targets. BROMOscan bromodomain profiling and biochemical assays support PCC as a BET inhibitor with increased selectivity for bromodomain (BD)-1 of BRD3 and BRD4, and X-ray crystallography and NMR studies uncovered specific contacts that underlie the potency and selectivity of PCC toward BRD3-BD1 over BRD3-BD2. PCC also displays characteristics of a molecular glue, facilitating proteasome-mediated degradation of BRD3 and BRD4.

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Homologous enzymes often exhibit different catalytic rates despite a fully conserved active site. The canonical view is that an enzyme sequence defines its structure and function and, more recently, that intrinsic protein dynamics at different time scales enable and/or promote catalytic activity. Here, we show that, using the protein tyrosine phosphatase PTP1B, residues surrounding the PTP1B active site promote dynamically coordinated chemistry necessary for PTP1B function.

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Background: Up to 70% of patients with ANCA-associated vasculitis (AAV) develop GN, with 26% progressing to ESKD. Diagnostic-grade and noninvasive tools to detect active renal inflammation are needed. Urinary soluble CD163 (usCD163) is a promising biomarker of active renal vasculitis, but a diagnostic-grade assay, assessment of its utility in prospective diagnosis of renal vasculitis flares, and evaluation of its utility in proteinuric states are needed.

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Background: Dyspnea is a common symptom in patients with end-stage kidney disease being treated with dialysis. This study aimed to ascertain the level of respiratory disability in patients after kidney transplantation through assessing a cohort of kidney allograft recipients for respiratory compromise and thereby identifying a potential target for therapeutic intervention.

Methods: Kidney transplant recipients who were under active observation in a single tertiary referral center were invited to take part in this prevalence study at the time of clinic follow-up.

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Background: Recent publications have shown patients with defects in the DNA mismatch repair (MMR) pathway driven by either MSH2 or MSH6 loss experience a significant increase in the incidence of prostate cancer. Moreover, this increased incidence of prostate cancer is accompanied by rapid disease progression and poor clinical outcomes.

Methods And Results: We show that androgen-receptor activation, a key driver of prostate carcinogenesis, can disrupt the MSH2 gene in prostate cancer.

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The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) entry into cells is a complex process that involves (1) recognition of the host entry receptor, angiotensin-converting enzyme 2 (ACE2), by the SARS-CoV-2 spike protein receptor binding domain (RBD), and (2) the subsequent fusion of the viral and cell membranes. Our long-term immune-defense is the production of antibodies (Abs) that recognize the SARS-CoV-2 RBD and successfully block viral infection. Thus, to understand immunity against SARS-CoV-2, a comprehensive molecular understanding of how human SARS-CoV-2 Abs recognize the RBD is needed.

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Article Synopsis
  • * Whole-genome sequencing was conducted on tissue samples from eight patients, and ctDNA was analyzed before and after prostate surgery; only two out of eight patients showed detectable ctDNA variants pre-treatment.
  • * The presence of ctDNA variants was linked to faster disease recurrence and progression, while specific TP53 mutations in ctDNA were associated with a significantly shorter metastasis-free survival, highlighting the potential prognostic value of ctDNA in localized prostate cancer.
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Protein-tyrosine phosphatase 1B (PTP1B) is the canonical enzyme for investigating how distinct structural elements influence enzyme catalytic activity. Although it is recognized that dynamics are essential for PTP1B function, the data collected thus far have not resolved whether distinct elements are dynamically coordinated or, alternatively, whether they fulfill their respective functions independently. To answer this question, we performed a comprehensive C-methyl relaxation study of Ile, Leu, and Val (ILV) residues of PTP1B, which, because of its substantially increased sensitivity, provides a comprehensive understanding of the influence of protein motions on different time scales for enzyme function.

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Cellular retinoic acid-binding protein 2 (CRABP2) delivers retinoic acid (atRA) to retinoic acid receptors (RARs), allowing for the activation of specific gene transcription. The structural similarities between free and atRA-bound CRABP2 raise the questions of how atRA binding occurs and how the atRA:CRABP2 complex is recognized by downstream binding partners. Thus, to gain insights into these questions, we conducted a detailed atRA-CRABP2 interaction study using nuclear magnetic resonance spectroscopy.

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DNA-fluorescence in situ hybridisation (DNA-FISH) allows visualisation of chromosome organisation and rearrangement. FISH probes are pools of short fluorescently labelled DNA fragments that are often produced from template plasmids that contain large genomic inserts. For effective sample penetration and target hybridisation it is critical that probe fragments are between 200 and 500bp.

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Eukaryotic elongation factor 2 kinase (eEF-2K), the only known calmodulin (CaM)-activated α-kinase, phosphorylates eukaryotic elongation factor 2 (eEF-2) on a specific threonine (Thr-56) diminishing its affinity for the ribosome and reducing the rate of nascent chain elongation during translation. Despite its critical cellular role, the precise mechanisms underlying the CaM-mediated activation of eEF-2K remain poorly defined. Here, employing a minimal eEF-2K construct (TR) that exhibits activity comparable to the wild-type enzyme and is fully activated by CaM in vitro and in cells, and using a variety of complimentary biophysical techniques in combination with computational modeling, we provide a structural mechanism by which CaM activates eEF-2K.

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Mitogen-activated protein kinases, which include p38, are essential for cell differentiation and autophagy. The current model for p38 activation involves activation-loop phosphorylation with subsequent substrate binding leading to substrate phosphorylation. Despite extensive efforts, the molecular mechanism of activation remains unclear.

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Rational design and directed evolution have proved to be successful approaches to increase catalytic efficiencies of both natural and artificial enzymes. Protein dynamics is recognized as important, but due to the inherent flexibility of biological macromolecules it is often difficult to distinguish which conformational changes are directly related to function. Here, we use directed evolution on an impaired mutant of the proline isomerase CypA and identify two second-shell mutations that partially restore its catalytic activity.

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Evidence suggests that altered adipose tissue homeostasis may be an important contributor to the development and/or progression of prostate cancer. In this study, we investigated the adipose transcriptional profiles of low- and high-risk disease to determine both prognostic potential and possible biological drivers of aggressive disease. RNA was extracted from periprostatic adipose tissue from patients categorised as having prostate cancer with either a low or high risk of progression based on tumour characteristics at prostatectomy and profiled by RNA sequencing.

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The present study investigated nutritional programming in Atlantic salmon to improve utilisation of a vegetable-based diet. At first exogenous feeding, fry were fed either a marine-based diet (Diet Mstimulus, 80% fishmeal (FM)/4% fish oil (FO)) or a vegetable-based diet (Diet Vstimulus, 10% FM/0% FO) for 3 weeks. Subsequently, all fish were then fed under the same conditions with a commercial, marine-based, diet for 15 weeks and thereafter challenged with a second V diet (Diet Vchallenge, 10% FM/0% FO) for 6 weeks.

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Neurological symptoms commonly occur in chronic kidney disease and may result from its treatments and complications. Impaired renal function also influences treatments for other neurological conditions, requiring various cautions, dose adjustments and timing considerations, particularly in the context of renal replacement therapy. In this review, we present six illustrative clinical vignettes to highlight these challenges.

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Background And Objectives: An environmental trigger has been proposed as an inciting factor in the development of anti-GBM disease. This multicenter, observational study sought to define the national incidence of anti-GBM disease during an 11-year period (2003-2014) in Ireland, investigate clustering of cases in time and space, and assess the effect of spatial variability in incidence on outcome.

Design, Setting, Participants, & Measurements: We ascertained cases by screening immunology laboratories for instances of positivity for anti-GBM antibody and the national renal histopathology registry for biopsy-proven cases.

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The maintenance of a pristine genome, free from errors, is necessary to prevent cellular transformation and degeneration. When errors in DNA are detected, DNA damage repair (DDR) genes and their regulators are activated to effect repair. When these DDR pathways are themselves mutated or aberrantly downregulated, cancer and neurodegenerative disorders can ensue.

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A specific biomarker that can separate active renal vasculitis from other causes of renal dysfunction is lacking, with a kidney biopsy often being required. Soluble CD163 (sCD163), shed by monocytes and macrophages, has been reported as a potential biomarker in diseases associated with excessive macrophage activation. Thus, we hypothesized that urinary sCD163 shed by crescent macrophages correlates with active glomerular inflammation.

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