PAX2 Regulates ADAM10 Expression and Mediates Anchorage-Independent Cell Growth of Melanoma Cells

PAX transcription factors play an important role during development and carcinogenesis. In this study, we investigated PAX2 protein levels in melanocytes and melanoma cells by Western Blot and immunofluorescence analysis and characterized the role of PAX2 in the pathogenesis of melanoma. In vitro we found weak PAX2 protein expression in keratinocytes and melanocytes. Compared to melanocytes increased PAX2 protein levels were detectable in melanoma cell lines. Interestingly, in tissue sections of melanoma patients nuclear PAX2 expression strongly correlated with nuclear atypia and the degree of prominent nucleoli, indicating an association of PAX2 with a more atypical cellular phenotype. In addition, with chromatin immunoprecipitation assay, PAX2 overexpression and PAX2 siRNA we present compelling evidence that PAX2 can regulate ADAM10 expression, a metalloproteinase known to play important roles in melanoma metastasis. In human tissue samples we found co-expression of PAX2 and ADAM10 in melanocytes of benign nevi and in melanoma cells of patients with malignant melanoma. Importantly, the downregulation of PAX2 by specific siRNA inhibited the anchorage independent cell growth and decreased the migratory and invasive capacity of melanoma cells. Furthermore, the downregulation of PAX2 abrogated the chemoresistance of melanoma cells against cisplatin, indicating that PAX2 expression mediates cell survival and plays important roles during melanoma progression

Selective inhibitors of cardiac ADPR cyclase as novel anti-arrhythmic compounds

ADP-ribosyl cyclases (ADPRCs) catalyse the conversion of nicotinamide adenine dinucleotide to cyclic adenosine diphosphoribose (cADPR) which is a second messenger involved in Ca2+ mobilisation from intracellular stores. Via its interaction with the ryanodine receptor Ca2+ channel in the heart, cADPR may exert arrhythmogenic activity. To test this hypothesis, we have studied the effect of novel cardiac ADPRC inhibitors in vitro and in vivo in models of ventricular arrhythmias. Using a high-throughput screening approach on cardiac sarcoplasmic reticulum membranes isolated from pig and rat and nicotinamide hypoxanthine dinuleotide as a surrogate substrate, we have identified potent and selective inhibitors of an intracellular, membrane-bound cardiac ADPRC that are different from the two known mammalian ADPRCs, CD38 and CD157/Bst1. We show that two structurally distinct cardiac ADPRC inhibitors, SAN2589 and SAN4825, prevent the formation of spontaneous action potentials in guinea pig papillary muscle in vitro and that compound SAN4825 is active in vivo in delaying ventricular fibrillation and cardiac arrest in a guinea pig model of Ca2+ overload-induced arrhythmia. Inhibition of cardiac ADPRC prevents Ca2+ overload-induced spontaneous depolarizations and ventricular fibrillation and may thus provide a novel therapeutic principle for the treatment of cardiac arrhythmias

Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector

A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements

Accuracy of controlled attenuation parameter measurement for the detection of steatosis in autoimmune liver diseases

Background & Aims: Concurrent fatty liver disease represents an emerging challenge in the care of individuals with autoimmune liver diseases (AILD). Therefore, we aimed to validate the ultrasound-based method of controlled-attenuation parameter (CAP) as a non-invasive tool to detect hepatic steatosis in individuals with AILD. Methods: The diagnostic performance of CAP to determine biopsy-proven hepatic steatosis (>5%) was assessed in individuals with AILD (autoimmune hepatitis [AIH], primary biliary cholangitis [PBC], primary biliary cholangitis [PSC], or variant syndromes) who underwent liver biopsy at the University Medical Center Hamburg-Eppendorf between 2015-2020 by calculating the area under the receiver operating characteristic (AUROC) curves. In AIH, the impact of disease activity was evaluated by assessment of CAP upon resolution of hepatic inflammation during follow-up. Results: Overall, 433 individuals with AILD (AIH: 218, PBC: 51, PSC: 85, PBC/AIH: 63, PSC/AIH: 16) were included. Histologically proven steatosis was present in 90 individuals (20.8%). Steatosis was less frequently observed in people with PSC (14%) than in other AILD. CAP values correlated positively with grade of steatosis (ρ = 0.39) and the BMI (ρ = 0.53). In PBC and PSC, the ROC curves defined an AUROC of 0.81 and 0.93 for detecting steatosis at an optimal cut-off of 276 dB/m (sensitivity: 0.71; specificity: 0.82) and 254 dB/m (sensitivity: 0.91, specificity: 0.85), respectively. In AIH, the diagnostic performance of CAP was significantly lower (AUROC = 0.72, p = 0.009). However, resolution of hepatic inflammation under treatment was associated with a significant increase in CAP levels (median [IQR]: +38.0 [6-81] dB/m) and considerably improved diagnostic accuracy (AUROC = 0.85; cut-off: 288 dB/m; sensitivity: 0.67, specificity: 0.90). Conclusions: In PBC and PSC, hepatic steatosis can be reliably detected by applying disease-specific thresholds of CAP. In AIH, the diagnostic accuracy of CAP is moderate at diagnosis, but improves after acute hepatitis has resolved. Impact and implications: Non-invasive estimation of fat content in the liver can be performed with the ultrasound-based method of controlled-attenuation parameter (CAP). Here, we showed that the presence of a concomitant fatty liver is frequent in people with autoimmune liver diseases and we determined disease-specific thresholds of CAP to best predict the presence of a fatty liver. CAP measurement was shown to be a valid tool to detect fatty liver in individuals with PSC and PBC; however, in AIH, CAP had limited accuracy especially when significant inflammatory activity was present in the liver. In the context of substantial liver inflammation, therefore, CAP values should be interpreted with caution, and measurements should be repeated after acute hepatitis has resolved

Evolution of organic aerosols in the atmosphere

Organic aerosol (OA) particles affect climate forcing and human health, but their sources and evolution remain poorly characterized. We present a unifying model framework describing the atmospheric evolution of OA that is constrained by high–time-resolution measurements of its composition, volatility, and oxidation state. OA and OA precursor gases evolve by becoming increasingly oxidized, less volatile, and more hygroscopic, leading to the formation of oxygenated organic aerosol (OOA), with concentrations comparable to those of sulfate aerosol throughout the Northern Hemisphere. Our model framework captures the dynamic aging behavior observed in both the atmosphere and laboratory: It can serve as a basis for improving parameterizations in regional and global models

Novel β‑Amino Acid Derivatives as Inhibitors of Cathepsin A

Cathepsin A (CatA) is a serine carboxypeptidase distributed between lysosomes, cell membrane, and extracellular space. Several peptide hormones including bradykinin and angiotensin I have been described as substrates. Therefore, the inhibition of CatA has the potential for beneficial effects in cardiovascular diseases. Pharmacological inhibition of CatA by the natural product ebelactone B increased renal bradykinin levels and prevented the development of salt-induced hypertension. However, so far no small molecule inhibitors of CatA with oral bioavailability have been described to allow further pharmacological profiling. In our work we identified novel β-amino acid derivatives as inhibitors of CatA after a HTS analysis based on a project adapted fragment approach. The new inhibitors showed beneficial ADME and pharmacokinetic profiles, and their binding modes were established by X-ray crystallography. Further investigations led to the identification of a hitherto unknown pathophysiological role of CatA in cardiac hypertrophy. One of our inhibitors is currently undergoing phase I clinical trials