From hormone replacement therapy to regenerative scaffolds:A review of current and novel primary hypothyroidism therapeutics

Primary hypothyroidism severely impacts the quality of life of patients through a decrease in the production of the thyroid hormones T3 and T4, leading to symptoms affecting cardiovascular, neurological, cognitive, and metabolic function. The incidence rate of primary hypothyroidism is expected to increase in the near future, partially due to increasing survival of patients that have undergone radiotherapy for head and neck cancer, which induces this disease in over half of those treated. The current standard of care encompasses thyroid hormone replacement therapy, traditionally in the form of synthetic T4. However, there is mounting evidence that this is unable to restore thyroid hormone signaling in all tissues due to often persistent symptoms. Additional complications are also present in the form of dosage difficulties, extensive drug interactions and poor patience compliance. The alternative therapeutic approach employed in the past is combination therapy, which consists of administration of both T3 and T4, either synthetic or in the form of desiccated thyroid extract. Here, issues are present regarding the lack of regulation concerning formulation and lack of data regarding safety and efficacy of these treatment methods. Tissue engineering and regenerative medicine have been applied in conjunction with each other to restore function of various tissues. Recently, these techniques have been adapted for thyroid tissue, primarily through the fabrication of regenerative scaffolds. Those currently under investigation are composed of either biopolymers or native decellularized extracellular matrix (dECM) in conjunction with either primary thyrocytes or stem cells which have undergone directed thyroid differentiation. Multiple of these scaffolds have successfully restored an athyroid phenotype in vivo. However, further work is needed until clinical translation can be achieved. This is proposed in the form of exploration and combination of materials used to fabricate these scaffolds, the addition of peptides which can aid restoration of tissue homeostasis and additional in vivo experimentation providing data on safety and efficacy of these implants

The mesh is a network of microtubule connectors that stabilizes individual kinetochore fibers of the mitotic spindle

Kinetochore fibers (K-fibers) of the mitotic spindle are force-generating units that power chromosome movement during mitosis. K-fibers are composed of many microtubules that are held together throughout their length. Here we show, using 3D electron microscopy, that K-fiber microtubules are connected by a network of microtubule connectors. We term this network 'the mesh'. The K-fiber mesh is made of linked multipolar connectors. Each connector has up to four struts, so that a single connector can link up to four microtubules. Molecular manipulation of the mesh by overexpression of TACC3 causes disorganization of the K-fiber microtubules. Optimal stabilization of K-fibers by the mesh is required for normal progression through mitosis. We propose that the mesh stabilizes K-fibers by pulling MTs together and thereby maintaining the integrity of the fiber. Our work thus identifies the K-fiber meshwork of linked multipolar connectors as a key integrator and determinant of K-fiber structure and function

Inhibition of neurite outgrowth in differentiating mouse N2a neuroblastoma cells by phenyl saligenin phosphate: Effects on MAP kinase (ERK 1/2) activation, neurofilament heavy chain phosphorylation and neuropathy target esterase activity

Sub-lethal concentrations of the organophosphate phenyl saligenin phosphate (PSP) inhibited the outgrowth of axon-like processes in differentiating mouse N2a neuroblastoma cells (IC50 2.5 μM). A transient rise in the phosphorylation state of neurofilament heavy chain (NFH) was detected on Western blots of cell extracts treated with 2.5 μM PSP for 4 h compared to untreated controls, as determined by a relative increase in reactivity with monoclonal antibody Ta51 (anti-phosphorylated NFH) compared to N52 (anti-total NFH). However, cross-reactivity of PSP-treated cell extracts was lower than that of untreated controls after 24 h exposure, as indicated by decreased reactivity with both antibodies. Indirect immunofluorescence analysis with these antibodies revealed the appearance of neurofilament aggregates in the cell bodies of treated cells and reduced axonal staining compared to controls. By contrast, there was no significant change in reactivity with anti-a tubulin antibody B512 at either time point. The activation state of the MAP kinase ERK 1/2 increased significantly after PSP treatment compared to controls, particularly at 4 h, as indicated by increased reactivity with monoclonal antibody E-4 (anti-phosphorylated MAP kinase) but not with polyclonal antibody K-23 (anti-total MAP kinase). The observed early changes were concomitant with almost complete inhibition of the activity of neuropathy target esterase (NTE), one of the proposed early molecular targets in organophosphate-induced delayed neuropathy (OPIDN)

Economics methods in Cochrane systematic reviews of health promotion and public health related interventions.

Peer reviewedPublisher PD

DYNamic assessment of multi‐organ level dysfunction in patients recovering from COVID‐19: DYNAMO COVID‐19

We evaluated the impacts of COVID‐19 on multi‐organ and metabolic function in patients following severe hospitalised infection compared to controls. Patients (n = 21) without previous diabetes, cardiovascular or cerebrovascular disease were recruited 5–7 months post‐discharge alongside controls (n = 10) with similar age, sex and body mass. Perceived fatigue was estimated (Fatigue Severity Scale) and the following were conducted: oral glucose tolerance (OGTT) alongside whole‐body fuel oxidation, validated magnetic resonance imaging and spectroscopy during resting and supine controlled exercise, dual‐energy X‐ray absorptiometry, short physical performance battery (SPPB), intra‐muscular electromyography, quadriceps strength and fatigability, and daily step‐count. There was a greater insulin response (incremental area under the curve, median (inter‐quartile range)) during the OGTT in patients [18,289 (12,497–27,448) mIU/min/L] versus controls [8655 (7948–11,040) mIU/min/L], P < 0.001. Blood glucose response and fasting and post‐prandial fuel oxidation rates were not different. This greater insulin resistance was not explained by differences in systemic inflammation or whole‐body/regional adiposity, but step‐count (P = 0.07) and SPPB scores (P = 0.004) were lower in patients. Liver volume was 28% greater in patients than controls, and fat fraction adjusted liver T1, a measure of inflammation, was raised in patients. Patients displayed greater perceived fatigue scores, though leg muscle volume, strength, force‐loss, motor unit properties and post‐exercise muscle phosphocreatine resynthesis were comparable. Further, cardiac and cerebral architecture and function (at rest and on exercise) were not different. In this cross‐sectional study, individuals without known previous morbidity who survived severe COVID‐19 exhibited greater insulin resistance, pointing to a need for physical function intervention in recovery

Absent expansion of AXIN2+ hepatocytes and altered physiology in Axin2CreERT2 mice challenges the role of pericentral hepatocytes in homeostatic liver regeneration

Background & Aims: Mouse models of lineage tracing have helped to describe the important subpopulations of hepatocytes responsible for liver regeneration. However, conflicting results have been obtained from different models. Herein, we aimed to reconcile these conflicting reports by repeating a key lineage-tracing study from pericentral hepatocytes and characterising this Axin2CreERT2 model in detail. Methods: We performed detailed characterisation of the labelled population in the Axin2CreERT2 model. We lineage traced this cell population, quantifying the labelled population over 1 year and performed in-depth phenotypic comparisons, including transcriptomics, metabolomics and analysis of proteins through immunohistochemistry, of Axin2CreERT2 mice to WT counterparts. Results: We found that after careful definition of a baseline population, there are marked differences in labelling between male and female mice. Upon induced lineage tracing there was no expansion of the labelled hepatocyte population in Axin2CreERT2 mice. We found substantial evidence of disrupted homeostasis in Axin2CreERT2 mice. Offspring are born with sub-Mendelian ratios and adult mice have perturbations of hepatic Wnt/β-catenin signalling and related metabolomic disturbance. Conclusions: We find no evidence of predominant expansion of the pericentral hepatocyte population during liver homeostatic regeneration. Our data highlight the importance of detailed preclinical model characterisation and the pitfalls which may occur when comparing across sexes and backgrounds of mice and the effects of genetic insertion into native loci. Impact and implications: Understanding the source of cells which regenerate the liver is crucial to harness their potential to regrow injured livers. Herein, we show that cells which were previously thought to repopulate the liver play only a limited role in physiological regeneration. Our data helps to reconcile differing conclusions drawn from results from a number of prior studies and highlights methodological challenges which are relevant to preclinical models more generally

Identification of Novel Antimalarial Chemotypes via Chemoinformatic Compound Selection Methods for a High-Throughput Screening Program against the Novel Malarial Target, PfNDH2: Increasing Hit Rate via Virtual Screening Methods

Malaria is responsible for approximately 1 million deaths annually; thus, continued efforts to discover new antimalarials are required. A HTS screen was established to identify novel inhibitors of the parasite's mitochondrial enzyme NADH:quinone oxidoreductase (PfNDH2). On the basis of only one known inhibitor of this enzyme, the challenge was to discover novel inhibitors of PfNDH2 with diverse chemical scaffolds. To this end, using a range of ligand-based chemoinformatics methods, ~17000 compounds were selected from a commercial library of ~750000 compounds. Forty-eight compounds were identified with PfNDH2 enzyme inhibition IC(50) values ranging from 100 nM to 40 μM and also displayed exciting whole cell antimalarial activity. These novel inhibitors were identified through sampling 16% of the available chemical space, while only screening 2% of the library. This study confirms the added value of using multiple ligand-based chemoinformatic approaches and has successfully identified novel distinct chemotypes primed for development as new agents against malaria

HNF4A and GATA6 loss reveals therapeutically actionable subtypes in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) can be divided into transcriptomic subtypes with two broad lineages referred to as classical (pancreatic) and squamous. We find that these two subtypes are driven by distinct metabolic phenotypes. Loss of genes that drive endodermal lineage specification, HNF4A and GATA6, switch metabolic profiles from classical (pancreatic) to predominantly squamous, with glycogen synthase kinase 3 beta (GSK3β) a key regulator of glycolysis. Pharmacological inhibition of GSK3β results in selective sensitivity in the squamous subtype; however, a subset of these squamous patient-derived cell lines (PDCLs) acquires rapid drug tolerance. Using chromatin accessibility maps, we demonstrate that the squamous subtype can be further classified using chromatin accessibility to predict responsiveness and tolerance to GSK3β inhibitors. Our findings demonstrate that distinct patterns of chromatin accessibility can be used to identify patient subgroups that are indistinguishable by gene expression profiles, highlighting the utility of chromatin-based biomarkers for patient selection in the treatment of PDAC

A broadband thermal emission spectrum of the ultra-hot Jupiter WASP-18b

Close-in giant exoplanets with temperatures greater than 2,000 K (''ultra-hot Jupiters'') have been the subject of extensive efforts to determine their atmospheric properties using thermal emission measurements from the Hubble and Spitzer Space Telescopes. However, previous studies have yielded inconsistent results because the small sizes of the spectral features and the limited information content of the data resulted in high sensitivity to the varying assumptions made in the treatment of instrument systematics and the atmospheric retrieval analysis. Here we present a dayside thermal emission spectrum of the ultra-hot Jupiter WASP-18b obtained with the NIRISS instrument on JWST. The data span 0.85 to 2.85 $\mu$m in wavelength at an average resolving power of 400 and exhibit minimal systematics. The spectrum shows three water emission features (at $>$6$\sigma$ confidence) and evidence for optical opacity, possibly due to H$^-$, TiO, and VO (combined significance of 3.8$\sigma$). Models that fit the data require a thermal inversion, molecular dissociation as predicted by chemical equilibrium, a solar heavy element abundance (''metallicity'', M/H = 1.03$_{-0.51}^{+1.11}$ $\times$ solar), and a carbon-to-oxygen (C/O) ratio less than unity. The data also yield a dayside brightness temperature map, which shows a peak in temperature near the sub-stellar point that decreases steeply and symmetrically with longitude toward the terminators.Comment: JWST ERS bright star observations. Uploaded to inform JWST Cycle 2 proposals. Manuscript under review. 50 pages, 14 figures, 2 table

A tetraoxane-based antimalarial drug candidate that overcomes PfK13-C580Y dependent artemisinin resistance.

K13 gene mutations are a primary marker of artemisinin resistance in Plasmodium falciparum malaria that threatens the long-term clinical utility of artemisinin-based combination therapies, the cornerstone of modern day malaria treatment. Here we describe a multinational drug discovery programme that has delivered a synthetic tetraoxane-based molecule, E209, which meets key requirements of the Medicines for Malaria Venture drug candidate profiles. E209 has potent nanomolar inhibitory activity against multiple strains of P. falciparum and P. vivax in vitro, is efficacious against P. falciparum in in vivo rodent models, produces parasite reduction ratios equivalent to dihydroartemisinin and has pharmacokinetic and pharmacodynamic characteristics compatible with a single-dose cure. In vitro studies with transgenic parasites expressing variant forms of K13 show no cross-resistance with the C580Y mutation, the primary variant observed in Southeast Asia. E209 is a superior next generation endoperoxide with combined pharmacokinetic and pharmacodynamic features that overcome the liabilities of artemisinin derivatives