Kinetics of cytokine receptor trafficking determine signaling and functional selectivity

Cytokines activate signaling via assembly of cell surface receptors, but it is unclear whether modulation of cytokine-receptor binding parameters can modify biological outcomes. We have engineered IL-6 variants with different affinities to gp130 to investigate how cytokine receptor binding dwell-times influence functional selectivity. Engineered IL-6 variants showed a range of signaling amplitudes and induced biased signaling, with changes in receptor binding dwell-times affecting more profoundly STAT1 than STAT3 phosphorylation. We show that this differential signaling arises from defective translocation of ligand-gp130 complexes to the endosomal compartment and competitive STAT1/STAT3 binding to phospho-tyrosines in gp130, and results in unique patterns of STAT3 binding to chromatin. This leads to a graded gene expression response and differences in ex vivo differentiation of Th17, Th1 and Treg cells. These results provide a molecular understanding of signaling biased by cytokine receptors, and demonstrate that manipulation of signaling thresholds is a useful strategy to decouple cytokine functional pleiotropy

Study of the signaling pathways activated by interferon alpha2 and interferon beta underlying differential biological activities

Le génome humain encode 3 familles d interféron : les interférons de type I (IFN / ), de type II (IFN ), de type III ( ). Chez l homme, les interférons de type I sont divisés en 16 sous-types très conservés, nommé IFN / . Ces cytokines se lient au récepteur à l interféron de type I constitué de deux sous-unités IFNAR1 et IFNAR2 induisant la même voie de signalisation Jak/Stat. Cependant le mécanisme moléculaire par lequel différents interférons agissent avec des activités biologiques différentes reste inconnu. La première partie de mon travail est axée sur l impact de la densité des récepteurs sur le potentiel biologique des différents sous-types d interférons. Puis j ai étudié l implication d une voie alternative à la voie des Stats dans le fort potentiel apoptotique et antiprolifératif de l IFN . Enfin, la dernière partie de ma thèse traite de la contribution des gènes ISRE- et GAS-dépendant dans la suppression de la croissance cellulaire induit par l interféronPARIS-BIUSJ-Physique recherche (751052113) / SudocSudocFranceF

The effect of anesthetic preconditioning with sevoflurane on intracellular signal-transduction pathways and apoptosis, in a lung autotransplant experimental model

Background: Anesthetic pre-conditioning attenuates inflammatory response during ischemia-reperfusion lung injury. The molecular mechanisms to explain it are not fully understood. The aim of our investigation was to analyze the molecular mechanism that explain the anti-inflammatory effects of anesthetic pre-conditioning with sevoflurane focusing on its effects on MAPKs (mitogen-activated protein kinases), NF-κB (nuclear factor kappa beta) pathways, and apoptosis in an experimental lung autotransplant model. Methods: Twenty large white pigs undergoing pneumonectomy plus lung autotransplant were divided into two 10-member groups on the basis of the anesthetic received (propofol or sevoflurane). Anesthetic pre-conditioning group received sevoflurane 3% after anesthesia induction and it stopped when one-lung ventilation get started. Control group did not receive sevoflurane in any moment during the whole study period. Intracellular signal-transduction pathways (MAPK family), transcription factor (NF-κB), and apoptosis (caspases 3 and 9) were analyzed during experiment. Results: Pigs that received anesthetic pre-conditioning with sevoflurane have shown significant lower values of MAPK-p38, MAPK-P-p38, JNK (c-Jun N-terminal kinases), NF-κB p50 intranuclear, and caspases (p < 0.05) than pigs anesthetized with intravenous propofol. Conclusions: Lung protection of anesthetic pre-conditioning with sevoflurane during experimental lung autotransplant is, at least, partially associated with MAPKs and NF κB pathways attenuation, and antiapoptotic effects. Resumo: Justificativa: O pré-condicionamento anestésico atenua a resposta inflamatória durante a lesão de isquemia-reperfusão do pulmão. Os mecanismos moleculares para explicá-lo não são totalmente compreendidos. O objetivo de nossa investigação foi analisar o mecanismo molecular que explica os efeitos anti-inflamatórios do pré-condicionamento anestésico com sevoflurano, enfocando seus efeitos sobre as proteínas quinases ativadas por mitógenos (MAPKs), o fator nuclear kappa beta (NF-κB) e a apoptose em modelo experimental de autotransplante pulmonar. Métodos: Vinte porcos Large White submetidos à pneumonectomia e autoimplante de pulmão foram divididos em dois grupos de 10 membros com base no anestésico recebido (propofol ou sevoflurano). O grupo de pré-condicionamento anestésico recebeu sevoflurano a 3% após a indução da anestesia, que foi descontinuado quando a ventilação monopulmonar foi iniciada. O grupo controle não recebeu sevoflurano em nenhum momento durante todo o período do estudo. As vias de transdução de sinal intracelular (família MAPK), o fator de transcrição (NF-κB) e a apoptose (caspases 3 e 9) foram analisados durante o experimento. Resultados: Os suínos que receberam pré-condicionamento anestésico com sevoflurano apresentaram valores mais baixos de MAPK-p38, MAPK-P-p38, c-Jun N-terminal quinases (JNK), NF-κB p50 intranuclear e caspases (p < 0,05) que os suínos anestesiados com propofol intravenoso. Conclusões: A proteção pulmonar do pré-condicionamento anestésico com sevoflurano durante o autotransplante pulmonar experimental está, pelo menos, parcialmente associada à atenuação das vias de MAPKs e NF κB e aos efeitos antiapoptóticos. Keywords: Lung transplantation, Sevoflurane, Inflammation, Apoptosis, Palavras-chave: Transplante pulmonar, Sevoflurano, Inflamação, Apoptos

BJS commission on surgery and perioperative care post-COVID-19

Background: Coronavirus disease 2019 (COVID-19) was declared a pandemic by the WHO on 11 March 2020 and global surgical practice was compromised. This Commission aimed to document and reflect on the changes seen in the surgical environment during the pandemic, by reviewing colleagues experiences and published evidence. Methods: In late 2020, BJS contacted colleagues across the global surgical community and asked them to describe how severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) had affected their practice. In addition to this, the Commission undertook a literature review on the impact of COVID-19 on surgery and perioperative care. A thematic analysis was performed to identify the issues most frequently encountered by the correspondents, as well as the solutions and ideas suggested to address them. Results: BJS received communications for this Commission from leading clinicians and academics across a variety of surgical specialties in every inhabited continent. The responses from all over the world provided insights into multiple facets of surgical practice from a governmental level to individual clinical practice and training. Conclusion: The COVID-19 pandemic has uncovered a variety of problems in healthcare systems, including negative impacts on surgical practice. Global surgical multidisciplinary teams are working collaboratively to address research questions about the future of surgery in the post-COVID-19 era. The COVID-19 pandemic is severely damaging surgical training. The establishment of a multidisciplinary ethics committee should be encouraged at all surgical oncology centres. Innovative leadership and collaboration is vital in the post-COVID-19 era

BJS commission on surgery and perioperative care post-COVID-19

Coronavirus disease 2019 (COVID-19) was declared a pandemic by the WHO on 11 March 2020 and global surgical practice was compromised. This Commission aimed to document and reflect on the changes seen in the surgical environment during the pandemic, by reviewing colleagues' experiences and published evidence