In plants, the highly abundant 2-cysteine peroxiredoxin (2-CysPrx) is associated with the chloroplast and involved in protecting photosynthesis. This work addresses the multiple interactions of the 2-CysPrx in the chloroplast, which depend on its redox state. Transcript co-regulation analysis showed a strong linkage to the peptidyl-prolyl-cis/trans isomerase Cyclophilin 20-3 (Cyp20-3) and other components of the photosynthetic apparatus. Co-expression in protoplasts and quantification of fluorescence resonance energy transfer (FRET) efficiency in vivo confirmed protein interactions of 2-CysPrx with Cyp20-3 as well as NADPH-dependent thioredoxin reductase C (NTRC), while thioredoxin x (Trx-x) did not form complexes that could enable FRET. Likewise, changes in FRET of fluorescently labeled 2-CysPrx in vitro and in vivo proved redox dependent dynamics of 2-CysPrx. Addition of Cyp20-3 to an in vitro peroxidase assay with 2-CysPrx had no significant effect on peroxide reduction. Also, in the presence of NTRC, addition of Cyp20-3 did not further enhance peroxide reduction. In addition, 2-CysPrx functioned as chaperone and inhibited aggregation of citrate synthase during heat treatment. This activity was partly inhibited by Cyp20-3. As a new interaction partner of decameric 2-CysPrx, photosystem II could be identified after chloroplast fractionation and in pull-down assays after reconstitution. In summary, the data indicate a dynamic function of plant 2-CysPrx as redox sensor, chaperone, and regulator in the chloroplast with diverse functions beyond its role as thiol peroxidase.
BackgroundAntigen (Ag)/IgE-mediated mast cell (MC) responses play detrimental roles in allergic diseases. MC activation via the high-affinity receptor for IgE (FcεRI) is controlled by the Src family kinase Lyn. Lyn-deficient (-/-) bone marrow-derived MCs (BMMCs) have been shown by various laboratories to exert stronger activation of the PI3K pathway, degranulation, and production of pro-inflammatory cytokines compared to wild-type (wt) cells. This mimics the phenotype of BMMCs deficient for the SH2-containing inositol-5’-phosphatase 1 (SHIP1). In this line, Lyn has been demonstrated to tyrosine-phosphorylate and activate SHIP1, thereby constituting a negative feedback control of PI3K-mediated signals. However, several groups have also reported on Lyn-/- BMMCs degranulating weaker than wt BMMCs.ResultsLyn-/- BMMCs, which show a suppressed degranulation response, were found to exhibit abrogated tyrosine phosphorylation of SHIP1 as well. This indicated that even in the presence of reduced SHIP1 function MC degranulation is dependent on Lyn function. In contrast to the reduced immediate secretory response, pro-inflammatory cytokine production was augmented in Lyn-/- BMMCs. For closer analysis, Lyn/SHIP1-double-deficient (dko) BMMCs were generated. In support of the dominance of Lyn deficiency, dko BMMCs degranulated significantly weaker than SHIP1-/- BMMCs. This coincided with reduced LAT1 and PLC-γ1 phosphorylation as well as Ca2+ mobilization in those cells. Interestingly, activation of the NFκB pathway followed the same pattern as measured by IκBα phosphorylation/degradation as well as induction of NFκB target genes. This suggested that Ag-triggered NFκB activation involves a Ca2+-dependent step. Indeed, IκBα phosphorylation/degradation and NFκB target gene induction were controlled by the Ca2+-dependent phosphatase calcineurin.ConclusionsLyn deficiency is dominant over SHIP1 deficiency in MCs with respect to Ag-triggered degranulation and preceding signaling events. Moreover, the NFκB pathway and respective targets are activated in a Lyn- and Ca2+-dependent manner, reinforcing the importance of Lyn for MC activation.Electronic supplementary materialThe online version of this article (doi:10.1186/s12964-016-0135-0) contains supplementary material, which is available to authorized users.
Zusammenfassung Ziel der Studie Aus der durch das Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) bedingten Coronavirus-Krankheit-2019 (COVID-19) haben sich Chancen und Herausforderungen für den Aufbau von Registern in der Versorgungsforschung ergeben. Diese sollen exemplarisch am aktuell größten sektorenübergreifenden Register mit einem detaillierten klinischen Datensatz zu mit SARS-CoV-2 infizierten Patient:innen in Deutschland, der Lean European Open Survey on SARS-CoV-2 Infected Patients (LEOSS), aufgezeigt werden. Methodik Ziele von LEOSS waren es, ein kollaboratives und integratives Register zur Erfassung von anonymen Daten aus der Versorgung zu schaffen und die Daten der Wissenschaft im Sinne eines Open Science Ansatzes rasch bereitzustellen. Alleiniges Einschlusskriterium war der virologische Nachweis von SARS-CoV-2. Schlüsselstrategien waren die Reallokation der vorhandenen personellen und technischen Ressourcen, die frühe und direkte Einbeziehung von Vertreter:innen des Datenschutzes und der Ethikkommissionen sowie die Entscheidung zu einem iterativen und agilen Entwicklungs- und Anpassungsprozess. Ergebnisse Getragen von den zahlreichen kollaborierenden Institutionen konnte ein transsektorales und internationales Netzwerk mit aktuell 133 aktiv rekrutierenden Standorten und 7227 dokumentierten Fällen aufgebaut werden (Stand 18.03.2021, ein Jahr seit Rekrutierungsstart von LEOSS). Die Nutzung der Daten wurde über auf der Projektwebseite verfügbare Werkzeuge zur Datenexploration, wie auch über die teilautomatisierte Bereitstellung von Datensätzen verschiedenen Umfangs, innerhalb kurzer Zeit ermöglicht. Es wurden 97 Anträge zur Datennutzung aus 27 Themengebieten begutachtet. Im Peer-Review-Verfahren wurden 9 Arbeiten in internationalen Fachzeitschriften veröffentlicht. Schlussfolgerung Mit LEOSS konnte in kürzester Zeit ein System zur Erfassung klinischer Verlaufsdaten zu COVID-19 in Deutschland etabliert werden. Auch wenn in anderen Projekten für spezifische Fragestellungen weitaus größere Datenbestände durch direkten Zugriff auf Quellsysteme analysiert werden konnten, wurde durch den einheitlich gepflegten und technisch geprüften Dokumentationsstandard mit vielen fachspezifischen Details ein sehr großer Datensatz mit wertvollen Alleinstellungsmerkmalen geschaffen. Aus den Erfahrungen von LEOSS können Implikationen für die zukünftige Gestaltung von Registern und eine rasche Reaktion auf Pandemien abgeleitet werden.
Purpose Reported antibiotic use in coronavirus disease 2019 (COVID-19) is far higher than the actual rate of reported bacterial co- and superinfection. A better understanding of antibiotic therapy in COVID-19 is necessary. Methods 6457 SARS-CoV-2-infected cases, documented from March 18, 2020, until February 16, 2021, in the LEOSS cohort were analyzed. As primary endpoint, the correlation between any antibiotic treatment and all-cause mortality/progression to the next more advanced phase of disease was calculated for adult patients in the complicated phase of disease and procalcitonin (PCT) ≤ 0.5 ng/ml. The analysis took the confounders gender, age, and comorbidities into account. Results Three thousand, six hundred twenty-seven cases matched all inclusion criteria for analyses. For the primary endpoint, antibiotic treatment was not correlated with lower all-cause mortality or progression to the next more advanced (critical) phase (n = 996) (both p > 0.05). For the secondary endpoints, patients in the uncomplicated phase (n = 1195), regardless of PCT level, had no lower all-cause mortality and did not progress less to the next more advanced (complicated) phase when treated with antibiotics (p > 0.05). Patients in the complicated phase with PCT > 0.5 ng/ml and antibiotic treatment (n = 286) had a significantly increased all-cause mortality (p = 0.029) but no significantly different probability of progression to the critical phase (p > 0.05). Conclusion In this cohort, antibiotics in SARS-CoV-2-infected patients were not associated with positive effects on all-cause mortality or disease progression. Additional studies are needed. Advice of local antibiotic stewardship- (ABS-) teams and local educational campaigns should be sought to improve rational antibiotic use in COVID-19 patients.
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