The role of the NO-cGMP pathway and the soluble guanylatcyclase in liver fibrosis

Leberfibrose, die gemeinsame Endstrecke aller chronischen Lebererkrankungen, ist weltweit ein großes Problem der öffentlichen Gesundheit. Der schwere Krankheitsverlauf und die Tatsache, dass es bis heute keine effiziente Therapie für eine erfolgreiche Behandlung gibt, spiegelt die dringende Notwendigkeit der weiteren Erforschung dieser Erkrankung für die Entwicklung von neuen antifibrotischen Therapien wieder. Da es erste Hinweise für eine antifibrotische Wirkung durch eine pharmakologische Modulation des NO-cGMP-Signalweges gibt, war das Ziel die therapeutische Relevanz einer spezifischen Intervention mit dem cGMP-erhöhenden sGC Stimulator BAY 41-2272 in der Leberfibrose zu überprüfen. Des Weiteren sollten die Beteiligung von NO und cGMP an den molekularen Pathomechanismen der Leberfibrose weiterführend untersucht werden. Um diese Fragen zu beantworten, wurden TGFß-aktivierte, leberspezifische Fibroblasten vom Menschen und von Ratten (= hepatic stellate cells) und zwei verschiedene in vivo Modelle (Gallengangsligatur- und Schweineserum Modell) verwendet. In vitro konnte eine konzentrationsabhängige Expressionssenkung von profibrotischen Markergenen unter der Behandlung mit dem sGC Stimulator BAY 41-2272 in beiden Fibroblastenspezies beobachtet werden. Diese direkte zelluläre, antifibrotische und speziesunabhängige Wirkung basierte auf den spezifischen sGC-vermittelten Anstieg der intrazellulären cGMP-Konzentration. Erste Daten weisen darauf hin, dass dieser cGMP-vermittelte, antifibrotische Mechanismus von BAY 41-2272 in der Leberfibrose z.T. PKG-abhängig sein kann. Durch die Verwendung von zwei verschiedenen Tiermodellen, sollte die direkte zelluläre, antifibrotische in vitro Wirkung von BAY 41-2272 hinsichtlich einer Übertragbarkeit auf die in vivo Situation untersucht werden. In beiden Leberfibrosetiermodellen senkte der sGC Stimulator BAY 41-2272 signifikant die pathologische Ansammlung von Kollagen und die Expression von profibrotischen Markergenen in der Leber. Darüber hinaus zeigten BAY 41-2272 behandelte Tiere eine signifikante Senkung des Portalvenendruckes ohne Veränderungen des systemischen Blutdruckes, was anhand von hämodynamischen Parametern aufgezeigt wurde. Zusammenfassend zeigen diese Ergebnisse eine direkte, antifibrotische Wirkung des sGC Stimulators BAY 41-2272 sowohl auf zellulärer Ebene als auch in Tiermodellen mit unterschiedlichen Ätiologien. Zusätzlich konnte die Beteiligung des NO-cGMP Signalweges in der Pathogenese der Leberfibrose bestätigt werden. Die vorteilhafte, drucksenkende Wirkung von BAY 41-2272 auf die portale Hypertension in den in vivo Experimenten zeigt, dass eine spezifische pharmakologische Stimulation der sGC das Potential einer neuen Behandlungsoption von leberfibrotischen Patienten haben könnte.Liver fibrosis, the final common pathway of all chronic liver diseases, is a major public health problem worldwide. The severity and progression of this disease and the fact that there is still no efficacious treatment available reflects the urgent need for further research to find new direct anti-fibrotic treatment options. Since there is a preliminary evidence for anti-fibrotic effects by the pharmacological modulation of the NO-cGMP pathway, the aim was to investigate the relevance of a specific therapeutic intervention with the cGMP-enhancing sGC stimulator BAY 41-2272 within liver fibrosis. Furthermore, the involvement of NO and cGMP during the molecular pathogenesis of liver fibrosis should be examined. To address these questions rat and human TGFß-activated, liver specific fibroblasts (= hepatic stellate cells) and two different in vivo models (bile duct ligation- and pig serum model) were used. In vitro, a concentration-dependent reduction of pro-fibrotic marker genes expressions was observed under the treatment with the sGC stimulator BAY 41-2272 in both fibroblasts species. This direct cellular, anti-fibrotic, species-independent effect was based on the specific sGC-mediated increase in intracellular cGMP concentration. First data suggested that the cGMP-mediated, anti-fibrotic mechanism of BAY 41-2272 in part can be PKG-dependent. By the use of two different animal models, we wanted to investigate whether the direct cellular, anti-fibrotic effect of BAY 41-2272 could be translated to the in vivo situation. In both animal models of liver fibrosis, the sGC stimulator BAY 41-2272 significantly reduced the collagen accumulation and the expression of pro-fibrotic marker genes in the liver tissue. Moreover, BAY 41-2272 treated animals showed a significant reduction of portal venous pressure without effects on systemic blood pressure as demonstrated by the measurement of hemodynamic parameters. In conclusion, these findings demonstrated a direct anti-fibrotic effect of the sGC stimulator BAY 41-2272 on the cellular level and in animal models of different etiology. Additionally the involvement of the NO-cGMP pathway in the pathogenesis of liver fibrosis was confirmed. The beneficial effect on portal hypertension in the in vivo experiments suggests that a specific pharmacological stimulation of the sGC might have the potential to become a new treatment option for liver fibrosis patients

Mistle: bringing spectral library predictions to metaproteomics with an efficient search index

Motivation Deep learning has moved to the forefront of tandem mass spectrometry-driven proteomics and authentic prediction for peptide fragmentation is more feasible than ever. Still, at this point spectral prediction is mainly used to validate database search results or for confined search spaces. Fully predicted spectral libraries have not yet been efficiently adapted to large search space problems that often occur in metaproteomics or proteogenomics. Results In this study, we showcase a workflow that uses Prosit for spectral library predictions on two common metaproteomes and implement an indexing and search algorithm, Mistle, to efficiently identify experimental mass spectra within the library. Hence, the workflow emulates a classic protein sequence database search with protein digestion but builds a searchable index from spectral predictions as an in-between step. We compare Mistle to popular search engines, both on a spectral and database search level, and provide evidence that this approach is more accurate than a database search using MSFragger. Mistle outperforms other spectral library search engines in terms of run time and proves to be extremely memory efficient with a 4- to 22-fold decrease in RAM usage. This makes Mistle universally applicable to large search spaces, e.g. covering comprehensive sequence databases of diverse microbiomes. Availability and implementation Mistle is freely available on GitHub at https://github.com/BAMeScience/Mistle

Plasma metabolomics and proteomics profiling after a postprandial challenge reveal subtle diet effects on human metabolic status

We introduce the metabolomics and proteomics based Postprandial Challenge Test (PCT) to quantify the postprandial response of multiple metabolic processes in humans in a standardized manner. The PCT comprised consumption of a standardized 500 ml dairy shake containing respectively 59, 30 and 12 energy percent lipids, carbohydrates and protein. During a 6 h time course after PCT 145 plasma metabolites, 79 proteins and 7 clinical chemistry parameters were quantified. Multiple processes related to metabolism, oxidation and inflammation reacted to the PCT, as demonstrated by changes of 106 metabolites, 31 proteins and 5 clinical chemistry parameters. The PCT was applied in a dietary intervention study to evaluate if the PCT would reveal additional metabolic changes compared to non-perturbed conditions. The study consisted of a 5-week intervention with a supplement mix of anti-inflammatory compounds in a crossover design with 36 overweight subjects. Of the 231 quantified parameters, 31 had different responses over time between treated and control groups, revealing differences in amino acid metabolism, oxidative stress, inflammation and endocrine metabolism. The results showed that the acute, short term metabolic responses to the PCT were different in subjects on the supplement mix compared to the controls. The PCT provided additional metabolic changes related to the dietary intervention not observed in non-perturbed conditions. Thus, a metabolomics based quantification of a standardized perturbation of metabolic homeostasis is more informative on metabolic status and subtle health effects induced by (dietary) interventions than quantification of the homeostatic situation

Cell Adhesion Molecules and Their Roles and Regulation in the Immune and Tumor Microenvironment

The immune system and cancer have a complex relationship with the immune system playing a dual role in tumor development. The effector cells of the immune system can recognize and kill malignant cells while immune system-mediated inflammation can also promote tumor growth and regulatory cells suppress the anti-tumor responses. In the center of all anti-tumor responses is the ability of the immune cells to migrate to the tumor site and to interact with each other and with the malignant cells. Cell adhesion molecules including receptors of the immunoglobulin superfamily and integrins are of crucial importance in mediating these processes. Particularly integrins play a vital role in regulating all aspects of immune cell function including immune cell trafficking into tissues, effector cell activation and proliferation and the formation of the immunological synapse between immune cells or between immune cell and the target cell both during homeostasis and during inflammation and cancer. In this review we discuss the molecular mechanisms regulating integrin function and the role of integrins and other cell adhesion molecules in immune responses and in the tumor microenvironment. We also describe how malignant cells can utilize cell adhesion molecules to promote tumor growth and metastases and how these molecules could be targeted in cancer immunotherapy.Peer reviewe

Statut vaccinal pour la coqueluche chez les professionnels de santé et à la maternité de l'hôpital de La Rochelle

POITIERS-BU Médecine pharmacie (861942103) / SudocSudocFranceF

Mistle: bringing spectral library predictions to metaproteomics with an efficient search index

Motivation: Deep learning has moved to the forefront of tandem mass spectrometry-driven proteomics and authentic prediction for peptide fragmentation is more feasible than ever. Still, at this point spectral prediction is mainly used to validate database search results or used for confined search spaces. Fully predicted spectral libraries have not yet been efficiently adapted to large search space problems that often occur in metaproteomics or proteogenomics. Results: In this study, we showcase a workflow that uses Prosit for spectral library predictions on two common metaproteomes and implement an indexing and search algorithm, Mistle, to efficiently identify experimental mass spectra within the library. Hence, the workflow emulates a classic protein sequence database search with protein digestion but builds a searchable index from spectral predictions as an in-between step. We compare Mistle to popular search engines, both on a spectral and database search level, and provide evidence that this approach is more accurate than a database search using MSFragger. Mistle outperforms other spectral library search engines in terms of run time and proves to be extremely memory efficient with an 8 to 22-fold decrease in RAM usage. This makes Mistle universally applicable to large search spaces, e.g. covering comprehensive sequence databases of diverse microbiomes. Availability: Mistle is freely available on GitHub at https://github.com/BAMeScience/Mistle