Discovery of novel GPVI receptor antagonists by structure-based repurposing.

Inappropriate platelet aggregation creates a cardiovascular risk that is largely managed with thienopyridines and aspirin. Although effective, these drugs carry risks of increased bleeding and drug 'resistance', underpinning a drive for new antiplatelet agents. To discover such drugs, one strategy is to identify a suitable druggable target and then find small molecules that modulate it. A good and unexploited target is the platelet collagen receptor, GPVI, which promotes thrombus formation. To identify inhibitors of GPVI that are safe and bioavailable, we docked a FDA-approved drug library into the GPVI collagen-binding site in silico. We now report that losartan and cinanserin inhibit GPVI-mediated platelet activation in a selective, competitive and dose-dependent manner. This mechanism of action likely underpins the cardioprotective effects of losartan that could not be ascribed to its antihypertensive effects. We have, therefore, identified small molecule inhibitors of GPVI-mediated platelet activation, and also demonstrated the utility of structure-based repurposing

conception, realization and an evaluation over four years

At the Hannover Medical School excursions into fields of medical activity include four elements: a lecture introducing the full range of fields of medical practice to all students, preparatory seminars for students after having chosen a special field (general medicine, public health agency, medical certification, medicine of addiction, industrial medicine, social psychiatry, medicine in prisons, social pediatrics, and forensic medicine), the practical part and a concluding seminar including an evaluation of the whole course program.In the present paper the results of evaluations over four years are described. Detailed findings are presented for the preparatory seminars, for the practical part, for the concluding seminars, and for a summary measure reflecting the general judgement of the students. After the end of the concluding seminars standardized questionnaires had to be completed, and 977 students returned them. The questionnaire covers a large number of aspects of the course. The statistical analyses are performed by means of nonparametric rank-ordering procedures and a regression analysis that also includes the general lecture.The general medicine program consistently got the highest rankings, followed by the public health agencies and industrial medicine. With the exception of industrial medicine the rankings of the preparatory and the concluding seminars are varying over the four years considered. Highly consistent rankings emerged for the practices and institutions that had been visited by the students. Furthermore, the analyses suggest that fields that had attracted particular interest before registration did not necessarily also obtained the highest rankings. The results of the regression analyses suggest that the concluding seminars and the general introducing lecture can be abolished since their didactic functions had not been apparent to the students.An der Medizinischen Hochschule Hannover besteht das Berufsfelderkundungspraktikum aus vier Elementen: einer Einführungsvorlesung zur Übersicht über die Breite ärztlicher Tätigkeitsfelder, vorbereitende Seminare in spezifische, von den Studierenden zu wählende und vorgegebene Berufsfelder (Hausbesuchsprogramm, Gesundheitsamt, MDK, Drogenmedizin, Arbeitsmedizin, Sozialpsychiatrie, Justizvollzug, Sozialpädiatrie und Rechtsmedizin), dem praktischen Teil in dem vorher gewählten Feld sowie einer Nachbereitung mit Beurteilung der Gesamtveranstaltung. Dargestellt werden die Ergebnisse der Evaluation über vier Durchgänge für die Vorbereitungsseminare, für die Betreuung in den aufnehmenden Einrichtungen und Praxen, für die Nachbereitung sowie die Ergebnisse der Gesamtbeurteilung durch die Absolventinnen und Absolventen.Insgesamt nahmen 977 Studierende an der Evaluation teil. Nach den Nachbereitungen füllten Sie einen standardisierten Fragebogen aus, der Fragen zu verschiedenen Aspekten des Praktikums enthält. Die statistischen Auswertungen wurden mittels Rangordnungsverfahren sowie einer Regressionsanalyse durchgeführt, die auch die Beurteilungen der Vorlesung berücksichtigt. Von den neun Praxisbereichen erhielt das Hausbesuchsprogramm in allen Praktikumsteilen die besten Beurteilungen, gefolgt von den Bereichen Gesundheitsamt und Arbeitsmedizin.Während die Beurteilungen der Einführungsseminare und der Nachbereitungen über die vier Jahre unterschiedlich eingestuft wurden, gibt es mit Ausnahme der Arbeitsmedizin eine hohe Konstanz in der Betreuung durch die besuchten Einrichtungen und Praxen. Die Analysen zeigen auch, dass die von den Studierenden mit Vorliebe gewählten Bereiche in den späteren Beurteilungen nicht notwendigerweise auch weit oben erscheinen müssen.Die Regressionsanalyse führte zu dem Schluss, dass die Nachbereitungsseminare und die allgemein orientierte Vorlesung künftig entfallen können, da ihre didaktische Bedeutung von den Studierenden nicht erkannt wird

Stromal Heterogeneity in the Human Proliferative Endometrium-A Single-Cell RNA Sequencing Study

The endometrium undergoes regular regeneration and stromal proliferation as part of the normal menstrual cycle. To better understand cellular interactions driving the mechanisms in endometrial regeneration we employed single-cell RNA sequencing. Endometrial biopsies were obtained during the proliferative phase of the menstrual cycle from healthy fertile women and processed to single-cell suspensions which were submitted for sequencing. In addition to known endometrial cell types, bioinformatic analysis revealed multiple stromal populations suggestive of specific stromal niches with the ability to control inflammation and extracellular matrix composition. Ten different stromal cells and two pericyte subsets were identified. Applying different R packages (Seurat, SingleR, Velocyto) we established cell cluster diversity and cell lineage/trajectory, while using external data to validate our findings. By understanding healthy regeneration in the described stromal compartments, we aim to identify points of further investigation and possible targets for novel therapy development for benign gynecological disorders affecting endometrial regeneration and proliferation such as endometriosis and Asherman's syndrome

EXP3179 inhibits collagen-dependent platelet activation via glycoprotein receptor-VI independent of AT1-receptor antagonism: Potential impact on atherothrombosis.

Thrombus formation after atherosclerotic plaque rupture critically involves the platelet collagen receptor glycoprotein (GP) VI. We investigated the impact of EXP3179, an active metabolite of the angiotensin II type 1 (AT1)-receptor antagonist Losartan (LOS) on GPVI-dependent platelet activation. METHODS AND RESULTS: EXP3179 and LOS but not EXP3174--the major AT1-receptor blocking metabolite of LOS--dose-dependently inhibited collagen-I (P<0.01) and GPVI-dependent platelet aggregation (P<0.01) analyzed by optical aggregometry. Platelet activation was further determined by flow cytometry measuring the expression of platelet PAC-1, an epitope of the activated fibrinogen-receptor complex. EXP3179 and LOS inhibited collagen-I (P<0.01) and GPVI-dependent PAC-1 expression (P<0.01). EXP3179 and LOS but not EXP3174 decreased the adhesion of GPVI-receptor expressing Chinese hamster ovarian cells on collagen-I under arterial shear conditions determined by flow chamber analysis (P<0.01 and P<0.05). EXP3179 also reduced human atherosclerotic plaque material-induced platelet aggregation (P<0.01) in vitro and murine platelet adhesion after acute vessel injury in vivo as determined by intravital microscopy (P<0.01). CONCLUSION: EXP3179 acts as a specific inhibitor of the platelet collagen receptor GPVI independent of AT1-receptor antagonism. Further investigations may clarify its individual potential as a novel pharmacological approach to specifically inhibit atherothrombotic events by GPVI-receptor blockade