100 research outputs found
Competing English, Spanish, and French alabaster trade in Europe over five centuries as evidenced by isotope fingerprinting
A lack of written sources is a serious obstacle in the reconstruction of the medieval trade of art and art materials, and in the identification of artists, workshop locations, and trade routes. We use the isotopes of sulfur, oxygen, and strontium (S, O, Sr) present in gypsum alabaster to unambiguously link ancient European source quarries and areas to alabaster artworks produced over five centuries (12th–17th) held by the Louvre museum in Paris and other European and American collections. Three principal alabaster production areas are identified, in central England, northern Spain, and a major, long-lived but little-documented alabaster trade radiating from the French Alps. The related trade routes are mostly fluvial, although terrestrial transport crossing the major river basin borders is also confirmed by historical sources. Our study also identifies recent artwork restoration using Italian alabaster and provides a robust geochemical framework for provenancing, including recognition of restoration and forgeries
Comparison of skin microvascular reactivity with hemostatic markers of endothelial dysfunction and damage in type 2 diabetes
AIM: Patients with non-insulin-dependent diabetes mellitus (NIDDM) are at increased cardiovascular risk due to an accelerated atherosclerotic process. The present study aimed to compare skin microvascular function, pulse wave velocity (PWV), and a variety of hemostatic markers of endothelium injury [von Willebrand factor (vWF), plasminogen activator inhibitor-1 (PAI-1), tissue plasminogen activator (t-PA), tissue factor pathway inhibitor (TFPI), and the soluble form of thrombomodulin (s-TM)] in patients with NIDDM. METHODS: 54 patients with NIDDM and 38 sex- and age-matched controls were studied. 27 diabetics had no overt micro- and/or macrovascular complications, while the remainder had either or both. The forearm skin blood flow was assessed by laser-Doppler imaging, which allowed the measurement of the response to iontophoretically applied acetylcholine (endothelium-dependent vasodilation) and sodium nitroprusside (endothelium-independent vasodilation), as well as the reactive hyperemia triggered by the transient occlusion of the circulation. RESULTS: Both endothelial and non-endothelial reactivity were significantly blunted in diabetics, regardless of the presence or the absence of vascular complications. Plasma vWF, TFPI and s-TM levels were significantly increased compared with controls only in patients exhibiting vascular complications. Concentrations of t-PA and PAI-1 were significantly increased in the two groups of diabetics versus controls. CONCLUSION: In NIDDM, both endothelium-dependent and -independent microvascular skin reactivity are impaired, whether or not underlying vascular complications exist. It also appears that microvascular endothelial dysfunction is not necessarily associated in NIDDM with increased circulating levels of hemostatic markers of endothelial damage known to reflect a hypercoagulable state
Potent Tau Aggregation Inhibitor D-Peptides Selected against Tau-Repeat 2 Using Mirror Image Phage Display
Alzheimer's disease and other Tauopathies are associated with neurofibrillary tangles composed of Tau protein, as well as toxic Tau oligomers. Therefore, inhibitors of pathological Tau aggregation are potentially useful candidates for future therapies targeting Tauopathies. Two hexapeptides within Tau, designated PHF6* (275-VQIINK-280) and PHF6 (306-VQIVYK-311), are known to promote Tau aggregation. Recently, the PHF6* segment has been described as the more potent driver of Tau aggregation. We therefore employed mirror-image phage display with a large peptide library to identify PHF6* fibril binding peptides consisting of D-enantiomeric amino acids. The suitability of D-enantiomeric peptides for in vivo applications, which are protease stable and less immunogenic than L-peptides, has already been demonstrated. The identified D-enantiomeric peptide MMD3 and its retro-inverso form, designated MMD3rev, inhibited in vitro fibrillization of the PHF6* peptide, the repeat domain of Tau as well as full-length Tau. Dynamic light scattering, pelleting assays and atomic force microscopy demonstrated that MMD3 prevents the formation of tau β-sheet-rich fibrils by diverting Tau into large amorphous aggregates. NMR data suggest that the D-enantiomeric peptides bound to Tau monomers with rather low affinity, but ELISA (enzyme-linked immunosorbent assay) data demonstrated binding to PHF6* and full length Tau fibrils. In addition, molecular insight into the binding mode of MMD3 to PHF6* fibrils were gained by in silico modelling. The identified PHF6*-targeting peptides were able to penetrate cells. The study establishes PHF6* fibril binding peptides consisting of D-enantiomeric amino acids as potential molecules for therapeutic and diagnostic applications in AD research
A novel D-amino acid peptide with therapeutic potential (ISAD1) inhibits aggregation of neurotoxic disease-relevant mutant Tau and prevents Tau toxicity in vitro
Background: Alzheimer's disease (AD), the most common form of dementia, is a progressive neurodegenerative disorder that mainly affects older adults. One of the pathological hallmarks of AD is abnormally aggregated Tau protein that forms fibrillar deposits in the brain. In AD, Tau pathology correlates strongly with clinical symptoms, cognitive dysfunction, and neuronal death.
Methods: We aimed to develop novel therapeutic D-amino acid peptides as Tau fibrillization inhibitors. It has been previously demonstrated that D-amino acid peptides are protease stable and less immunogenic than L-peptides, and these characteristics may render them suitable for in vivo applications. Using a phage display procedure against wild type full-length Tau (TauFL), we selected a novel Tau binding L-peptide and synthesized its D-amino acid version ISAD1 and its retro inversed form, ISAD1rev, respectively.
Results: While ISAD1rev inhibited Tau aggregation only moderately, ISAD1 bound to Tau in the aggregation-prone PHF6 region and inhibited fibrillization of TauFL, disease-associated mutant full-length Tau (TauFLΔK, TauFL-A152T, TauFL-P301L), and pro-aggregant repeat domain Tau mutant (TauRDΔK). ISAD1 and ISAD1rev induced the formation of large high molecular weight TauFL and TauRDΔK oligomers that lack proper Thioflavin-positive β-sheet conformation even at lower concentrations. In silico modeling of ISAD1 Tau interaction at the PHF6 site revealed a binding mode similar to those known for other PHF6 binding peptides. Cell culture experiments demonstrated that ISAD1 and its inverse form are taken up by N2a-TauRDΔK cells efficiently and prevent cytotoxicity of externally added Tau fibrils as well as of internally expressed TauRDΔK.
Conclusions: ISAD1 and related peptides may be suitable for therapy development of AD by promoting off-pathway assembly of Tau, thus preventing its toxicity.
Keywords: Alzheimer’s disease; D-amino acid peptides; Phage display; Tau aggregation inhibitors; Therap
Single-cell RNA sequencing uncovers the nuclear decoy lincRNA PIRAT as a regulator of systemic monocyte immunity during COVID-19
The systemic immune response to viral infection is shaped by master transcription fac-tors, such as NF-κB, STAT1, or PU.1. Although long noncoding RNAs (lncRNAs)have been suggested as important regulators of transcription factor activity, their contri-butions to the systemic immunopathologies observed during SARS-CoV-2 infectionhave remained unknown. Here, we employed a targeted single-cell RNA sequencingapproach to reveal lncRNAs differentially expressed in blood leukocytes during severeCOVID-19. Our results uncover the lncRNA PIRAT (PU.1-induced regulator of alar-min transcription) as a major PU.1 feedback-regulator in monocytes, governing the pro-duction of the alarmins S100A8/A9, key drivers of COVID-19 pathogenesis. Knockoutand transgene expression, combined with chromatin-occupancy profiling, characterizedPIRATasanucleardecoyRNA,keepingPU.1frombindingtoalarminpromotersandpromoting its binding to pseudogenes in naïve monocytes. NF-κB–dependent PIRATdown-regulation during COVID-19 consequently releases a transcriptional brake, fuelingalarmin production. Alarmin expression is additionally enhanced by the up-regulation ofthe lncRNA LUCAT1, which promotes NF-κB–dependentgeneexpressionattheexpenseof targets of the JAK-STAT pathway. Our results suggest a major role of nuclear noncod-ing RNA networks in systemic antiviral responses to SARS-CoV-2 in humans
MARK4 controls ischaemic heart failure through microtubule detyrosination.
Myocardial infarction is a major cause of premature death in adults. Compromised cardiac function after myocardial infarction leads to chronic heart failure with systemic health complications and a high mortality rate1. Effective therapeutic strategies are needed to improve the recovery of cardiac function after myocardial infarction. More specifically, there is a major unmet need for a new class of drugs that can improve cardiomyocyte contractility, because inotropic therapies that are currently available have been associated with high morbidity and mortality in patients with systolic heart failure2,3 or have shown a very modest reduction of risk of heart failure4. Microtubule detyrosination is emerging as an important mechanism for the regulation of cardiomyocyte contractility5. Here we show that deficiency of microtubule-affinity regulating kinase 4 (MARK4) substantially limits the reduction in the left ventricular ejection fraction after acute myocardial infarction in mice, without affecting infarct size or cardiac remodelling. Mechanistically, we provide evidence that MARK4 regulates cardiomyocyte contractility by promoting phosphorylation of microtubule-associated protein 4 (MAP4), which facilitates the access of vasohibin 2 (VASH2)-a tubulin carboxypeptidase-to microtubules for the detyrosination of α-tubulin. Our results show how the detyrosination of microtubules in cardiomyocytes is finely tuned by MARK4 to regulate cardiac inotropy, and identify MARK4 as a promising therapeutic target for improving cardiac function after myocardial infarction.BHF fellowship grant (FS/14/28/30713), Issac Newton Trust Grant (18.40u), and Cambridge BHF Centre of Research Excellence grants (RE/13/6/30180 and RE/18/1/34212)
Effect of 24 Hours of Normoglycaemia on Tissue-Type Plasminogen Activator Plasma Levels in Insulin Dependent Diabetes
Venous Occlusion Does Not Induce the Release of Thrombomodulin from Endothelial Cells in Patients with Thromboembolic Disease
Increased PA-Inhibitor Levels in the Postoperative Period – No Cause-Effect Relation with Increased Cortisol
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