28 research outputs found

    Finishing the euchromatic sequence of the human genome

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    The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

    The Role of Drosophila α-Catenin in Growth Regulation and EMT

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    α-catenin (Drosophila α-Cat) links the cadherin-catenin complex to actomyosin at adherens junctions (AJs) in epithelial cells. I investigated the role of α-Cat in proliferation control and whether α-Cat acts as a mechanosensor at the AJs to regulate Hippo signaling. I showed that α-Cat has a dosage-dependent effect on proliferation and survival. α-Cat has distinct functions in growth regulation and adhesion, acting through JNK and the Hippo pathway. α-Cat null cells undergo EMT. Intermediate loss of α-Cat resulted in overgrowth. I found that α-Cat acts as an AJ component to regulate growth. Moreover, I showed that the mechanosensitive M region of α-Cat is dispensable for adhesion and proliferation control. My work identified a novel role for α-Cat as a growth regulator at the AJs, in addition to adhesion. This work will stimulate future investigations into how the α-Cat-centered protein network contributes to growth regulation in development and cancer progression.M.Sc.2018-11-30 00:00:0

    Non-equilibrium Condensation in the Actomyosin Cortex

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    Cells use energy to maintain order, as living systems are inherently non-equilibrium. Or- der in the cytoplasm is achieved by compartmentalization. One type of compartment that gained interest in recent years is membraneless organelles (MLOs). Observations of the liquid-like properties of MLOs led to their interpretation in analogy to Liquid-Liquid Phase Separation (LLPS). However, LLPS alone implies a passive closed system that tends towards equilibrium, which is incompatible with the physical nature of the cell. It is unclear then what non-equilibrium interactions give rise to the dynamics of MLOs in the cell. We sought to decipher the regulatory interactions that give rise to active condensation in the actomyosin cortex of C. elegans. The components of the actomyosin cortex, F- actin and its branching nucleation module Arp2/3 and N-WASP (WSP-1 in C. elegans) have been described as a phase separated system in previous reports. In vitro, phase separated N-WASP compartments do not have the non-equilibrium growth and disas- sembly dynamics observed in the multicomponent clusters in vivo. Therefore, our goal is to examine WSP-1, Arp2/3 and F-actin interactions in the endogenous context. We chose the stage in which the quiescent oocyte cortex becomes actively contractile. During the transition out of quiescence, we observed transient WSP-1 Arp2/3 F-actin puncta that assemble and disassemble. To capture growth dynamics for all puncta, we devel- oped a novel phase portrait analysis tool. The phase portrait allows us to simultaneously study puncta growth and disassembly rates as a function of internal composition. The growth rate dependence on internal composition reflects the non-trivial changes to nu- cleation profiles that accompany condensation in active, open, multi-component systems. We observed superlinear WSP-1 growth rates consistent with condensation. Further, we identified the in vivo equivalent of a nucleation barrier for WSP-1 condensation. The in vivo nucleation barrier increases with branching F-actin reaction, which tunes con- densation. Correspondingly, the reactive components WSP-1 and Arp2/3 are important for condensate dynamics. Combining condensation and the branching reaction, we for- mulated a coarse-grained model which captures non-equilibrium condensate dynamics. Altogether, our results showed that WSP-1 grows like condensation, and its growth is steered away from equilibrium by Arp2/3 mediated branching reaction. In summary, combining high-resolution imaging, quantitative analysis and theory, we identified the interactions that could explain non-equilibrium condensation in the acto- myosin cortex. The living dynamics that arise from the interplay between condensation and reaction. The interplay between physical processes (like condensation) and biological regulation (such as reactions) may be a common organizing principle behind MLO for- mation, as well as other non-equilibrium processes in the cell. The methods and concepts developed in this work hold the promise to deepen our understanding of how living cells regulate their dynamic organization, in order to maintain themselves in a non-equilibrium ordered state.:1 Introduction 1 1.1 Evolving concepts of cellular organization 1 1.2 Condensation of biomolecules 3 1.2.1 Terminology for biomolecular condensates 5 1.2.2 Technical considerations for identifying liquid-like properties and LLPS 7 1.2.3 Thermodynamics of condensation 10 1.2.4 The problem of an equilibrium description of living systems 13 1.2.5 Towards active condensation 14 1.3 Actomyosin cortex self-organization 16 1.3.1 F-actin treadmilling and nucleation 17 1.3.2 N-WASP and Arp2/3 regulation 18 1.3.3 Multivalent interactions in condensation of transmembrane receptors and actin regulators 22 1.3.4 Cortex activation in C. elegans 23 2 Aims 25 3 Results 26 3.1 C. elegans cortical activation begins at fertilization 26 3.1.1 C. elegans oocytes as an ex utero model for cortex self-organization 27 3.2 WSP-1, Arp2/3 and F-actin form dynamic multicomponent phases 32 3.2.1 Capping proteins outcompete Formin in WSP-1 Arp2/3 puncta preventing F-actin elongation 32 3.2.2 WSP-1 and Arp2/3 are required for punctate F-actin formation and dynamics 34 3.2.3 Summary of the characterization of cortical activation 34 3.3 Establishment of systematic phase portrait analysis for multicomponent clusters 36 3.3.1 Non-equilibrium features of the multicomponent puncta 36 3.3.2 Recording intensity traces of multicomponent cluster over time 37 3.3.3 Probability flux of composition in the phase portrait show a closed cycle 38 3.3.4 WSP-1 F-actin puncta have a preferred joint concentration 38 3.3.5 The phase portrait is robust to cell-to-cell noise 41 3.3.6 Choosing the appropriate bin size 41 3.4 Existence of a tuned critical size and signatures of active condensation 45 3.4.1 Growth rate dependence on internal composition 45 3.4.2 Stoichiometric growth laws of WSP-1 F-actin clusters 47 3.4.3 Estimation of WSP-1 cluster critical size in vivo 47 3.4.4 Theoretical description of WSP-1 and F-actin interactions in regulating puncta dynamics 48 3.4.5 Summary of 2D phase portrait findings 52 3.5 Towards three dimensional phase portrait analysis of the reaction network 54 3.6 Initial assessment of the compartment’s external environment 54 3.7 Identification of modulators of puncta dynamics 56 3.7.1 CDC-42 controls cortical levels of WSP-1 56 3.7.2 RHO-1 and Formin CYK-1 are not involved in WSP-1 F-actin condensate dynamics 58 3.7.3 WSP-1 and Arp2/3 dynamics are independent of NCK-1 and VAB-1 58 3.7.4 Arp2/3 regulates condensate dynamics 60 3.8 Summary of perturbations 63 4 Conclusions and outlook 64 4.1 Concluding remarks 64 4.2 Discussion 66 4.3 Future directions 67 4.3.1 Realizing the full potential of the phase portraits in identifying biochemical interactions 67 4.3.2 Resolving the ultrastructure of condensates . 70 4.3.3 Further investigation of the biological function 71 4.3.4 Applying full-dynamic data acquisition to other membraneless organelles 71 5 Materials and Methods 72 5.1 C.elegans maintenance and strains 72 5.2 Sample preparation 72 5.2.1 In utero imaging 72 5.2.2 Oocyte imaging 73 5.2.3 C.elegans HaloTag staining 73 5.2.4 Oocyte chemical inhibitor treatments 73 5.3 RNAi Feeding 73 5.4 Microscopy 73 5.4.1 Spinning disk microscopy 73 5.4.2 SIM-TIRF microscopy 74 5.5 TIRF microscopy 74 5.6 Phase portrait analysis pipeline 74 5.7 Kymographs 76Zellen verbrauchen Energie, um Ordnung aufrechtzuerhalten, da lebende Systeme von Natur aus ungleichgewichtig sind. Ordnung im Zytoplasma wird durch Kompartimen- tierung erreicht. Eine Art von Kompartiment, das in den letzten Jahren an Interesse gewonnen hat, sind membranlose Organellen (engl.: membraneless organelles, MLOs). Beobachtungen der flu ̈ssigkeits ̈ahnlichen Eigenschaften dieser MLOs fu ̈hrten zu ihrer In- terpretation in Analogie zur Flu ̈ssig-Flu ̈ssig-Phasentrennung (engl.: liquid-liquid phase separation, LLPS). Die LLPS allein impliziert jedoch ein passives geschlossenes System, das zum Gleichgewicht neigt und mit der physikalischen Natur der Zelle nicht kompatibel ist. Es war bisher nicht bekannt, welche Ungleichgewichtswechselwirkungen die Dynamik von MLOs in der Zelle hervorrufen. Wir wollten die regulatorischen Wechselwirkungen entschlu ̈sseln, die zu aktiver Konden- sation im Aktomyosin-Kortex von C. elegans fu ̈hren. Die Komponenten des Aktomyosin- Kortex, F-Aktin und seines verzweigten Nukleationsmoduls Arp2/3 und N-WASP (WSP- 1 in C. elegans) wurden in fru ̈heren Studien als phasengetrenntes System beschrieben. In vitro weisen phasengetrennte N-WASP-Kompartimente allerdings nicht dieselben un- gleichgewichtigen Wachstums- und Zerlegungsdynamiken auf, die in kultivierten Zellen beobachtet werden. Daher wollten wir die Wechselwirkungen zwischen WSP-1, Arp2/3 und F-Aktin im Kontext des Fadenwurms C. elegans untersuchen. Wir haben das C.elegans Lebenstadium gew ̈ahlt, in dem die ruhende Eizellenrinde aktiv kontraktil wird. Wa ̈hrend des U ̈bergangs aus der ruhigen in die aktive Periode konnten wir voru ̈bergehende WSP- 1 Arp2/3 F-Aktin-Puncta beobachten, die sich zusammensetzen und zerlegen. Um die Wachstumsdynamik fu ̈r alle Puncta zu erfassen, haben wir ein neuartiges Tool zur Anal- yse von Phasenportr ̈ats entwickelt. Das Phasenportr ̈at ermo ̈glicht es uns, gleichzeitig die Wachstums- und die Zerlegungsraten von Puncta in Abha ̈ngigkeit der inneren Zusam- mensetzung zu messen. Die Abha ̈ngigkeit der Wachstumsrate von der inneren Zusam- mensetzung spiegelt die nicht trivialen A ̈nderungen der Nukleationsprofile wider, die mit der Kondensation in aktiven, offenen Mehrkomponentensystemen einhergehen. Wir kon- nten superlineare WSP-1-Wachstumsraten beobachten, die mit der Kondensation u ̈bere- instimmen. Ferner konnten wir das In-vivo-A ̈quivalent einer Nukleationsbarriere fu ̈r die WSP-1-Kondensation identifizieren. Die In-vivo-Nukleationsbarriere nimmt mit der verzweigten F-Actin-Reaktion zu, die die Kondensation reguliert. Dementsprechend sind die reaktiven Komponenten WSP-1 und Arp2/3 wichtig fu ̈r die Dynamik des Konden- sats. Wir haben die Kondensations- und Verzweigungsreaktionen kombiniert, um damit ein grobko ̈rniges Modell zu formulieren, das die Ungleichgewichtskondensationsdynamik erfasst. Insgesamt haben unsere Ergebnisse gezeigt, dass WSP-1 kondensiert und diese Kondensation durch Arp2/3-vermittelte Verzweigungsreaktionen aus dem Gleichgewicht gebracht wird. Zusammenfassend konnten wir durch Kombination von hochauflo ̈sender Bildgebung, quan- titativer Analyse und Theorie die Wechselwirkungen identifizieren, die die Ungleichgewicht- skondensation im Aktomyosin-Kortex erkla ̈ren ko ̈nnten. Die Dynamik im lebendem Sys- tem ergibt sich aus dem Zusammenspiel von Kondensation und Reaktion. Die Interaktion zwischen physikalischen Prozessen (wie Kondensation) und biologischen Regulationen (wie Reaktionen) kann ein gemeinsames Organisationsprinzip hinter der MLO-Bildung sowie anderen Ungleichgewichtsprozessen in der Zelle sein. Die in dieser Arbeit entwickel- ten Methoden und Konzepte k ̈onnen daher helfen, unser Versta ̈ndnis daru ̈ber zu vertiefen, wie lebende Zellen ihre r ̈aumlich-zeitlichen Proteinverteilungen dynamisch regulieren, um sich in einem ungleichgewichtigen, geordneten Zustand zu halten.:1 Introduction 1 1.1 Evolving concepts of cellular organization 1 1.2 Condensation of biomolecules 3 1.2.1 Terminology for biomolecular condensates 5 1.2.2 Technical considerations for identifying liquid-like properties and LLPS 7 1.2.3 Thermodynamics of condensation 10 1.2.4 The problem of an equilibrium description of living systems 13 1.2.5 Towards active condensation 14 1.3 Actomyosin cortex self-organization 16 1.3.1 F-actin treadmilling and nucleation 17 1.3.2 N-WASP and Arp2/3 regulation 18 1.3.3 Multivalent interactions in condensation of transmembrane receptors and actin regulators 22 1.3.4 Cortex activation in C. elegans 23 2 Aims 25 3 Results 26 3.1 C. elegans cortical activation begins at fertilization 26 3.1.1 C. elegans oocytes as an ex utero model for cortex self-organization 27 3.2 WSP-1, Arp2/3 and F-actin form dynamic multicomponent phases 32 3.2.1 Capping proteins outcompete Formin in WSP-1 Arp2/3 puncta preventing F-actin elongation 32 3.2.2 WSP-1 and Arp2/3 are required for punctate F-actin formation and dynamics 34 3.2.3 Summary of the characterization of cortical activation 34 3.3 Establishment of systematic phase portrait analysis for multicomponent clusters 36 3.3.1 Non-equilibrium features of the multicomponent puncta 36 3.3.2 Recording intensity traces of multicomponent cluster over time 37 3.3.3 Probability flux of composition in the phase portrait show a closed cycle 38 3.3.4 WSP-1 F-actin puncta have a preferred joint concentration 38 3.3.5 The phase portrait is robust to cell-to-cell noise 41 3.3.6 Choosing the appropriate bin size 41 3.4 Existence of a tuned critical size and signatures of active condensation 45 3.4.1 Growth rate dependence on internal composition 45 3.4.2 Stoichiometric growth laws of WSP-1 F-actin clusters 47 3.4.3 Estimation of WSP-1 cluster critical size in vivo 47 3.4.4 Theoretical description of WSP-1 and F-actin interactions in regulating puncta dynamics 48 3.4.5 Summary of 2D phase portrait findings 52 3.5 Towards three dimensional phase portrait analysis of the reaction network 54 3.6 Initial assessment of the compartment’s external environment 54 3.7 Identification of modulators of puncta dynamics 56 3.7.1 CDC-42 controls cortical levels of WSP-1 56 3.7.2 RHO-1 and Formin CYK-1 are not involved in WSP-1 F-actin condensate dynamics 58 3.7.3 WSP-1 and Arp2/3 dynamics are independent of NCK-1 and VAB-1 58 3.7.4 Arp2/3 regulates condensate dynamics 60 3.8 Summary of perturbations 63 4 Conclusions and outlook 64 4.1 Concluding remarks 64 4.2 Discussion 66 4.3 Future directions 67 4.3.1 Realizing the full potential of the phase portraits in identifying biochemical interactions 67 4.3.2 Resolving the ultrastructure of condensates . 70 4.3.3 Further investigation of the biological function 71 4.3.4 Applying full-dynamic data acquisition to other membraneless organelles 71 5 Materials and Methods 72 5.1 C.elegans maintenance and strains 72 5.2 Sample preparation 72 5.2.1 In utero imaging 72 5.2.2 Oocyte imaging 73 5.2.3 C.elegans HaloTag staining 73 5.2.4 Oocyte chemical inhibitor treatments 73 5.3 RNAi Feeding 73 5.4 Microscopy 73 5.4.1 Spinning disk microscopy 73 5.4.2 SIM-TIRF microscopy 74 5.5 TIRF microscopy 74 5.6 Phase portrait analysis pipeline 74 5.7 Kymographs 7

    Non-equilibrium Condensation in the Actomyosin Cortex

    No full text
    Cells use energy to maintain order, as living systems are inherently non-equilibrium. Or- der in the cytoplasm is achieved by compartmentalization. One type of compartment that gained interest in recent years is membraneless organelles (MLOs). Observations of the liquid-like properties of MLOs led to their interpretation in analogy to Liquid-Liquid Phase Separation (LLPS). However, LLPS alone implies a passive closed system that tends towards equilibrium, which is incompatible with the physical nature of the cell. It is unclear then what non-equilibrium interactions give rise to the dynamics of MLOs in the cell. We sought to decipher the regulatory interactions that give rise to active condensation in the actomyosin cortex of C. elegans. The components of the actomyosin cortex, F- actin and its branching nucleation module Arp2/3 and N-WASP (WSP-1 in C. elegans) have been described as a phase separated system in previous reports. In vitro, phase separated N-WASP compartments do not have the non-equilibrium growth and disas- sembly dynamics observed in the multicomponent clusters in vivo. Therefore, our goal is to examine WSP-1, Arp2/3 and F-actin interactions in the endogenous context. We chose the stage in which the quiescent oocyte cortex becomes actively contractile. During the transition out of quiescence, we observed transient WSP-1 Arp2/3 F-actin puncta that assemble and disassemble. To capture growth dynamics for all puncta, we devel- oped a novel phase portrait analysis tool. The phase portrait allows us to simultaneously study puncta growth and disassembly rates as a function of internal composition. The growth rate dependence on internal composition reflects the non-trivial changes to nu- cleation profiles that accompany condensation in active, open, multi-component systems. We observed superlinear WSP-1 growth rates consistent with condensation. Further, we identified the in vivo equivalent of a nucleation barrier for WSP-1 condensation. The in vivo nucleation barrier increases with branching F-actin reaction, which tunes con- densation. Correspondingly, the reactive components WSP-1 and Arp2/3 are important for condensate dynamics. Combining condensation and the branching reaction, we for- mulated a coarse-grained model which captures non-equilibrium condensate dynamics. Altogether, our results showed that WSP-1 grows like condensation, and its growth is steered away from equilibrium by Arp2/3 mediated branching reaction. In summary, combining high-resolution imaging, quantitative analysis and theory, we identified the interactions that could explain non-equilibrium condensation in the acto- myosin cortex. The living dynamics that arise from the interplay between condensation and reaction. The interplay between physical processes (like condensation) and biological regulation (such as reactions) may be a common organizing principle behind MLO for- mation, as well as other non-equilibrium processes in the cell. The methods and concepts developed in this work hold the promise to deepen our understanding of how living cells regulate their dynamic organization, in order to maintain themselves in a non-equilibrium ordered state.:1 Introduction 1 1.1 Evolving concepts of cellular organization 1 1.2 Condensation of biomolecules 3 1.2.1 Terminology for biomolecular condensates 5 1.2.2 Technical considerations for identifying liquid-like properties and LLPS 7 1.2.3 Thermodynamics of condensation 10 1.2.4 The problem of an equilibrium description of living systems 13 1.2.5 Towards active condensation 14 1.3 Actomyosin cortex self-organization 16 1.3.1 F-actin treadmilling and nucleation 17 1.3.2 N-WASP and Arp2/3 regulation 18 1.3.3 Multivalent interactions in condensation of transmembrane receptors and actin regulators 22 1.3.4 Cortex activation in C. elegans 23 2 Aims 25 3 Results 26 3.1 C. elegans cortical activation begins at fertilization 26 3.1.1 C. elegans oocytes as an ex utero model for cortex self-organization 27 3.2 WSP-1, Arp2/3 and F-actin form dynamic multicomponent phases 32 3.2.1 Capping proteins outcompete Formin in WSP-1 Arp2/3 puncta preventing F-actin elongation 32 3.2.2 WSP-1 and Arp2/3 are required for punctate F-actin formation and dynamics 34 3.2.3 Summary of the characterization of cortical activation 34 3.3 Establishment of systematic phase portrait analysis for multicomponent clusters 36 3.3.1 Non-equilibrium features of the multicomponent puncta 36 3.3.2 Recording intensity traces of multicomponent cluster over time 37 3.3.3 Probability flux of composition in the phase portrait show a closed cycle 38 3.3.4 WSP-1 F-actin puncta have a preferred joint concentration 38 3.3.5 The phase portrait is robust to cell-to-cell noise 41 3.3.6 Choosing the appropriate bin size 41 3.4 Existence of a tuned critical size and signatures of active condensation 45 3.4.1 Growth rate dependence on internal composition 45 3.4.2 Stoichiometric growth laws of WSP-1 F-actin clusters 47 3.4.3 Estimation of WSP-1 cluster critical size in vivo 47 3.4.4 Theoretical description of WSP-1 and F-actin interactions in regulating puncta dynamics 48 3.4.5 Summary of 2D phase portrait findings 52 3.5 Towards three dimensional phase portrait analysis of the reaction network 54 3.6 Initial assessment of the compartment’s external environment 54 3.7 Identification of modulators of puncta dynamics 56 3.7.1 CDC-42 controls cortical levels of WSP-1 56 3.7.2 RHO-1 and Formin CYK-1 are not involved in WSP-1 F-actin condensate dynamics 58 3.7.3 WSP-1 and Arp2/3 dynamics are independent of NCK-1 and VAB-1 58 3.7.4 Arp2/3 regulates condensate dynamics 60 3.8 Summary of perturbations 63 4 Conclusions and outlook 64 4.1 Concluding remarks 64 4.2 Discussion 66 4.3 Future directions 67 4.3.1 Realizing the full potential of the phase portraits in identifying biochemical interactions 67 4.3.2 Resolving the ultrastructure of condensates . 70 4.3.3 Further investigation of the biological function 71 4.3.4 Applying full-dynamic data acquisition to other membraneless organelles 71 5 Materials and Methods 72 5.1 C.elegans maintenance and strains 72 5.2 Sample preparation 72 5.2.1 In utero imaging 72 5.2.2 Oocyte imaging 73 5.2.3 C.elegans HaloTag staining 73 5.2.4 Oocyte chemical inhibitor treatments 73 5.3 RNAi Feeding 73 5.4 Microscopy 73 5.4.1 Spinning disk microscopy 73 5.4.2 SIM-TIRF microscopy 74 5.5 TIRF microscopy 74 5.6 Phase portrait analysis pipeline 74 5.7 Kymographs 76Zellen verbrauchen Energie, um Ordnung aufrechtzuerhalten, da lebende Systeme von Natur aus ungleichgewichtig sind. Ordnung im Zytoplasma wird durch Kompartimen- tierung erreicht. Eine Art von Kompartiment, das in den letzten Jahren an Interesse gewonnen hat, sind membranlose Organellen (engl.: membraneless organelles, MLOs). Beobachtungen der flu ̈ssigkeits ̈ahnlichen Eigenschaften dieser MLOs fu ̈hrten zu ihrer In- terpretation in Analogie zur Flu ̈ssig-Flu ̈ssig-Phasentrennung (engl.: liquid-liquid phase separation, LLPS). Die LLPS allein impliziert jedoch ein passives geschlossenes System, das zum Gleichgewicht neigt und mit der physikalischen Natur der Zelle nicht kompatibel ist. Es war bisher nicht bekannt, welche Ungleichgewichtswechselwirkungen die Dynamik von MLOs in der Zelle hervorrufen. Wir wollten die regulatorischen Wechselwirkungen entschlu ̈sseln, die zu aktiver Konden- sation im Aktomyosin-Kortex von C. elegans fu ̈hren. Die Komponenten des Aktomyosin- Kortex, F-Aktin und seines verzweigten Nukleationsmoduls Arp2/3 und N-WASP (WSP- 1 in C. elegans) wurden in fru ̈heren Studien als phasengetrenntes System beschrieben. In vitro weisen phasengetrennte N-WASP-Kompartimente allerdings nicht dieselben un- gleichgewichtigen Wachstums- und Zerlegungsdynamiken auf, die in kultivierten Zellen beobachtet werden. Daher wollten wir die Wechselwirkungen zwischen WSP-1, Arp2/3 und F-Aktin im Kontext des Fadenwurms C. elegans untersuchen. Wir haben das C.elegans Lebenstadium gew ̈ahlt, in dem die ruhende Eizellenrinde aktiv kontraktil wird. Wa ̈hrend des U ̈bergangs aus der ruhigen in die aktive Periode konnten wir voru ̈bergehende WSP- 1 Arp2/3 F-Aktin-Puncta beobachten, die sich zusammensetzen und zerlegen. Um die Wachstumsdynamik fu ̈r alle Puncta zu erfassen, haben wir ein neuartiges Tool zur Anal- yse von Phasenportr ̈ats entwickelt. Das Phasenportr ̈at ermo ̈glicht es uns, gleichzeitig die Wachstums- und die Zerlegungsraten von Puncta in Abha ̈ngigkeit der inneren Zusam- mensetzung zu messen. Die Abha ̈ngigkeit der Wachstumsrate von der inneren Zusam- mensetzung spiegelt die nicht trivialen A ̈nderungen der Nukleationsprofile wider, die mit der Kondensation in aktiven, offenen Mehrkomponentensystemen einhergehen. Wir kon- nten superlineare WSP-1-Wachstumsraten beobachten, die mit der Kondensation u ̈bere- instimmen. Ferner konnten wir das In-vivo-A ̈quivalent einer Nukleationsbarriere fu ̈r die WSP-1-Kondensation identifizieren. Die In-vivo-Nukleationsbarriere nimmt mit der verzweigten F-Actin-Reaktion zu, die die Kondensation reguliert. Dementsprechend sind die reaktiven Komponenten WSP-1 und Arp2/3 wichtig fu ̈r die Dynamik des Konden- sats. Wir haben die Kondensations- und Verzweigungsreaktionen kombiniert, um damit ein grobko ̈rniges Modell zu formulieren, das die Ungleichgewichtskondensationsdynamik erfasst. Insgesamt haben unsere Ergebnisse gezeigt, dass WSP-1 kondensiert und diese Kondensation durch Arp2/3-vermittelte Verzweigungsreaktionen aus dem Gleichgewicht gebracht wird. Zusammenfassend konnten wir durch Kombination von hochauflo ̈sender Bildgebung, quan- titativer Analyse und Theorie die Wechselwirkungen identifizieren, die die Ungleichgewicht- skondensation im Aktomyosin-Kortex erkla ̈ren ko ̈nnten. Die Dynamik im lebendem Sys- tem ergibt sich aus dem Zusammenspiel von Kondensation und Reaktion. Die Interaktion zwischen physikalischen Prozessen (wie Kondensation) und biologischen Regulationen (wie Reaktionen) kann ein gemeinsames Organisationsprinzip hinter der MLO-Bildung sowie anderen Ungleichgewichtsprozessen in der Zelle sein. Die in dieser Arbeit entwickel- ten Methoden und Konzepte k ̈onnen daher helfen, unser Versta ̈ndnis daru ̈ber zu vertiefen, wie lebende Zellen ihre r ̈aumlich-zeitlichen Proteinverteilungen dynamisch regulieren, um sich in einem ungleichgewichtigen, geordneten Zustand zu halten.:1 Introduction 1 1.1 Evolving concepts of cellular organization 1 1.2 Condensation of biomolecules 3 1.2.1 Terminology for biomolecular condensates 5 1.2.2 Technical considerations for identifying liquid-like properties and LLPS 7 1.2.3 Thermodynamics of condensation 10 1.2.4 The problem of an equilibrium description of living systems 13 1.2.5 Towards active condensation 14 1.3 Actomyosin cortex self-organization 16 1.3.1 F-actin treadmilling and nucleation 17 1.3.2 N-WASP and Arp2/3 regulation 18 1.3.3 Multivalent interactions in condensation of transmembrane receptors and actin regulators 22 1.3.4 Cortex activation in C. elegans 23 2 Aims 25 3 Results 26 3.1 C. elegans cortical activation begins at fertilization 26 3.1.1 C. elegans oocytes as an ex utero model for cortex self-organization 27 3.2 WSP-1, Arp2/3 and F-actin form dynamic multicomponent phases 32 3.2.1 Capping proteins outcompete Formin in WSP-1 Arp2/3 puncta preventing F-actin elongation 32 3.2.2 WSP-1 and Arp2/3 are required for punctate F-actin formation and dynamics 34 3.2.3 Summary of the characterization of cortical activation 34 3.3 Establishment of systematic phase portrait analysis for multicomponent clusters 36 3.3.1 Non-equilibrium features of the multicomponent puncta 36 3.3.2 Recording intensity traces of multicomponent cluster over time 37 3.3.3 Probability flux of composition in the phase portrait show a closed cycle 38 3.3.4 WSP-1 F-actin puncta have a preferred joint concentration 38 3.3.5 The phase portrait is robust to cell-to-cell noise 41 3.3.6 Choosing the appropriate bin size 41 3.4 Existence of a tuned critical size and signatures of active condensation 45 3.4.1 Growth rate dependence on internal composition 45 3.4.2 Stoichiometric growth laws of WSP-1 F-actin clusters 47 3.4.3 Estimation of WSP-1 cluster critical size in vivo 47 3.4.4 Theoretical description of WSP-1 and F-actin interactions in regulating puncta dynamics 48 3.4.5 Summary of 2D phase portrait findings 52 3.5 Towards three dimensional phase portrait analysis of the reaction network 54 3.6 Initial assessment of the compartment’s external environment 54 3.7 Identification of modulators of puncta dynamics 56 3.7.1 CDC-42 controls cortical levels of WSP-1 56 3.7.2 RHO-1 and Formin CYK-1 are not involved in WSP-1 F-actin condensate dynamics 58 3.7.3 WSP-1 and Arp2/3 dynamics are independent of NCK-1 and VAB-1 58 3.7.4 Arp2/3 regulates condensate dynamics 60 3.8 Summary of perturbations 63 4 Conclusions and outlook 64 4.1 Concluding remarks 64 4.2 Discussion 66 4.3 Future directions 67 4.3.1 Realizing the full potential of the phase portraits in identifying biochemical interactions 67 4.3.2 Resolving the ultrastructure of condensates . 70 4.3.3 Further investigation of the biological function 71 4.3.4 Applying full-dynamic data acquisition to other membraneless organelles 71 5 Materials and Methods 72 5.1 C.elegans maintenance and strains 72 5.2 Sample preparation 72 5.2.1 In utero imaging 72 5.2.2 Oocyte imaging 73 5.2.3 C.elegans HaloTag staining 73 5.2.4 Oocyte chemical inhibitor treatments 73 5.3 RNAi Feeding 73 5.4 Microscopy 73 5.4.1 Spinning disk microscopy 73 5.4.2 SIM-TIRF microscopy 74 5.5 TIRF microscopy 74 5.6 Phase portrait analysis pipeline 74 5.7 Kymographs 7

    Non-equilibrium Condensation in the Actomyosin Cortex

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    Cells use energy to maintain order, as living systems are inherently non-equilibrium. Or- der in the cytoplasm is achieved by compartmentalization. One type of compartment that gained interest in recent years is membraneless organelles (MLOs). Observations of the liquid-like properties of MLOs led to their interpretation in analogy to Liquid-Liquid Phase Separation (LLPS). However, LLPS alone implies a passive closed system that tends towards equilibrium, which is incompatible with the physical nature of the cell. It is unclear then what non-equilibrium interactions give rise to the dynamics of MLOs in the cell. We sought to decipher the regulatory interactions that give rise to active condensation in the actomyosin cortex of C. elegans. The components of the actomyosin cortex, F- actin and its branching nucleation module Arp2/3 and N-WASP (WSP-1 in C. elegans) have been described as a phase separated system in previous reports. In vitro, phase separated N-WASP compartments do not have the non-equilibrium growth and disas- sembly dynamics observed in the multicomponent clusters in vivo. Therefore, our goal is to examine WSP-1, Arp2/3 and F-actin interactions in the endogenous context. We chose the stage in which the quiescent oocyte cortex becomes actively contractile. During the transition out of quiescence, we observed transient WSP-1 Arp2/3 F-actin puncta that assemble and disassemble. To capture growth dynamics for all puncta, we devel- oped a novel phase portrait analysis tool. The phase portrait allows us to simultaneously study puncta growth and disassembly rates as a function of internal composition. The growth rate dependence on internal composition reflects the non-trivial changes to nu- cleation profiles that accompany condensation in active, open, multi-component systems. We observed superlinear WSP-1 growth rates consistent with condensation. Further, we identified the in vivo equivalent of a nucleation barrier for WSP-1 condensation. The in vivo nucleation barrier increases with branching F-actin reaction, which tunes con- densation. Correspondingly, the reactive components WSP-1 and Arp2/3 are important for condensate dynamics. Combining condensation and the branching reaction, we for- mulated a coarse-grained model which captures non-equilibrium condensate dynamics. Altogether, our results showed that WSP-1 grows like condensation, and its growth is steered away from equilibrium by Arp2/3 mediated branching reaction. In summary, combining high-resolution imaging, quantitative analysis and theory, we identified the interactions that could explain non-equilibrium condensation in the acto- myosin cortex. The living dynamics that arise from the interplay between condensation and reaction. The interplay between physical processes (like condensation) and biological regulation (such as reactions) may be a common organizing principle behind MLO for- mation, as well as other non-equilibrium processes in the cell. The methods and concepts developed in this work hold the promise to deepen our understanding of how living cells regulate their dynamic organization, in order to maintain themselves in a non-equilibrium ordered state.:1 Introduction 1 1.1 Evolving concepts of cellular organization 1 1.2 Condensation of biomolecules 3 1.2.1 Terminology for biomolecular condensates 5 1.2.2 Technical considerations for identifying liquid-like properties and LLPS 7 1.2.3 Thermodynamics of condensation 10 1.2.4 The problem of an equilibrium description of living systems 13 1.2.5 Towards active condensation 14 1.3 Actomyosin cortex self-organization 16 1.3.1 F-actin treadmilling and nucleation 17 1.3.2 N-WASP and Arp2/3 regulation 18 1.3.3 Multivalent interactions in condensation of transmembrane receptors and actin regulators 22 1.3.4 Cortex activation in C. elegans 23 2 Aims 25 3 Results 26 3.1 C. elegans cortical activation begins at fertilization 26 3.1.1 C. elegans oocytes as an ex utero model for cortex self-organization 27 3.2 WSP-1, Arp2/3 and F-actin form dynamic multicomponent phases 32 3.2.1 Capping proteins outcompete Formin in WSP-1 Arp2/3 puncta preventing F-actin elongation 32 3.2.2 WSP-1 and Arp2/3 are required for punctate F-actin formation and dynamics 34 3.2.3 Summary of the characterization of cortical activation 34 3.3 Establishment of systematic phase portrait analysis for multicomponent clusters 36 3.3.1 Non-equilibrium features of the multicomponent puncta 36 3.3.2 Recording intensity traces of multicomponent cluster over time 37 3.3.3 Probability flux of composition in the phase portrait show a closed cycle 38 3.3.4 WSP-1 F-actin puncta have a preferred joint concentration 38 3.3.5 The phase portrait is robust to cell-to-cell noise 41 3.3.6 Choosing the appropriate bin size 41 3.4 Existence of a tuned critical size and signatures of active condensation 45 3.4.1 Growth rate dependence on internal composition 45 3.4.2 Stoichiometric growth laws of WSP-1 F-actin clusters 47 3.4.3 Estimation of WSP-1 cluster critical size in vivo 47 3.4.4 Theoretical description of WSP-1 and F-actin interactions in regulating puncta dynamics 48 3.4.5 Summary of 2D phase portrait findings 52 3.5 Towards three dimensional phase portrait analysis of the reaction network 54 3.6 Initial assessment of the compartment’s external environment 54 3.7 Identification of modulators of puncta dynamics 56 3.7.1 CDC-42 controls cortical levels of WSP-1 56 3.7.2 RHO-1 and Formin CYK-1 are not involved in WSP-1 F-actin condensate dynamics 58 3.7.3 WSP-1 and Arp2/3 dynamics are independent of NCK-1 and VAB-1 58 3.7.4 Arp2/3 regulates condensate dynamics 60 3.8 Summary of perturbations 63 4 Conclusions and outlook 64 4.1 Concluding remarks 64 4.2 Discussion 66 4.3 Future directions 67 4.3.1 Realizing the full potential of the phase portraits in identifying biochemical interactions 67 4.3.2 Resolving the ultrastructure of condensates . 70 4.3.3 Further investigation of the biological function 71 4.3.4 Applying full-dynamic data acquisition to other membraneless organelles 71 5 Materials and Methods 72 5.1 C.elegans maintenance and strains 72 5.2 Sample preparation 72 5.2.1 In utero imaging 72 5.2.2 Oocyte imaging 73 5.2.3 C.elegans HaloTag staining 73 5.2.4 Oocyte chemical inhibitor treatments 73 5.3 RNAi Feeding 73 5.4 Microscopy 73 5.4.1 Spinning disk microscopy 73 5.4.2 SIM-TIRF microscopy 74 5.5 TIRF microscopy 74 5.6 Phase portrait analysis pipeline 74 5.7 Kymographs 76Zellen verbrauchen Energie, um Ordnung aufrechtzuerhalten, da lebende Systeme von Natur aus ungleichgewichtig sind. Ordnung im Zytoplasma wird durch Kompartimen- tierung erreicht. Eine Art von Kompartiment, das in den letzten Jahren an Interesse gewonnen hat, sind membranlose Organellen (engl.: membraneless organelles, MLOs). Beobachtungen der flu ̈ssigkeits ̈ahnlichen Eigenschaften dieser MLOs fu ̈hrten zu ihrer In- terpretation in Analogie zur Flu ̈ssig-Flu ̈ssig-Phasentrennung (engl.: liquid-liquid phase separation, LLPS). Die LLPS allein impliziert jedoch ein passives geschlossenes System, das zum Gleichgewicht neigt und mit der physikalischen Natur der Zelle nicht kompatibel ist. Es war bisher nicht bekannt, welche Ungleichgewichtswechselwirkungen die Dynamik von MLOs in der Zelle hervorrufen. Wir wollten die regulatorischen Wechselwirkungen entschlu ̈sseln, die zu aktiver Konden- sation im Aktomyosin-Kortex von C. elegans fu ̈hren. Die Komponenten des Aktomyosin- Kortex, F-Aktin und seines verzweigten Nukleationsmoduls Arp2/3 und N-WASP (WSP- 1 in C. elegans) wurden in fru ̈heren Studien als phasengetrenntes System beschrieben. In vitro weisen phasengetrennte N-WASP-Kompartimente allerdings nicht dieselben un- gleichgewichtigen Wachstums- und Zerlegungsdynamiken auf, die in kultivierten Zellen beobachtet werden. Daher wollten wir die Wechselwirkungen zwischen WSP-1, Arp2/3 und F-Aktin im Kontext des Fadenwurms C. elegans untersuchen. Wir haben das C.elegans Lebenstadium gew ̈ahlt, in dem die ruhende Eizellenrinde aktiv kontraktil wird. Wa ̈hrend des U ̈bergangs aus der ruhigen in die aktive Periode konnten wir voru ̈bergehende WSP- 1 Arp2/3 F-Aktin-Puncta beobachten, die sich zusammensetzen und zerlegen. Um die Wachstumsdynamik fu ̈r alle Puncta zu erfassen, haben wir ein neuartiges Tool zur Anal- yse von Phasenportr ̈ats entwickelt. Das Phasenportr ̈at ermo ̈glicht es uns, gleichzeitig die Wachstums- und die Zerlegungsraten von Puncta in Abha ̈ngigkeit der inneren Zusam- mensetzung zu messen. Die Abha ̈ngigkeit der Wachstumsrate von der inneren Zusam- mensetzung spiegelt die nicht trivialen A ̈nderungen der Nukleationsprofile wider, die mit der Kondensation in aktiven, offenen Mehrkomponentensystemen einhergehen. Wir kon- nten superlineare WSP-1-Wachstumsraten beobachten, die mit der Kondensation u ̈bere- instimmen. Ferner konnten wir das In-vivo-A ̈quivalent einer Nukleationsbarriere fu ̈r die WSP-1-Kondensation identifizieren. Die In-vivo-Nukleationsbarriere nimmt mit der verzweigten F-Actin-Reaktion zu, die die Kondensation reguliert. Dementsprechend sind die reaktiven Komponenten WSP-1 und Arp2/3 wichtig fu ̈r die Dynamik des Konden- sats. Wir haben die Kondensations- und Verzweigungsreaktionen kombiniert, um damit ein grobko ̈rniges Modell zu formulieren, das die Ungleichgewichtskondensationsdynamik erfasst. Insgesamt haben unsere Ergebnisse gezeigt, dass WSP-1 kondensiert und diese Kondensation durch Arp2/3-vermittelte Verzweigungsreaktionen aus dem Gleichgewicht gebracht wird. Zusammenfassend konnten wir durch Kombination von hochauflo ̈sender Bildgebung, quan- titativer Analyse und Theorie die Wechselwirkungen identifizieren, die die Ungleichgewicht- skondensation im Aktomyosin-Kortex erkla ̈ren ko ̈nnten. Die Dynamik im lebendem Sys- tem ergibt sich aus dem Zusammenspiel von Kondensation und Reaktion. Die Interaktion zwischen physikalischen Prozessen (wie Kondensation) und biologischen Regulationen (wie Reaktionen) kann ein gemeinsames Organisationsprinzip hinter der MLO-Bildung sowie anderen Ungleichgewichtsprozessen in der Zelle sein. Die in dieser Arbeit entwickel- ten Methoden und Konzepte k ̈onnen daher helfen, unser Versta ̈ndnis daru ̈ber zu vertiefen, wie lebende Zellen ihre r ̈aumlich-zeitlichen Proteinverteilungen dynamisch regulieren, um sich in einem ungleichgewichtigen, geordneten Zustand zu halten.:1 Introduction 1 1.1 Evolving concepts of cellular organization 1 1.2 Condensation of biomolecules 3 1.2.1 Terminology for biomolecular condensates 5 1.2.2 Technical considerations for identifying liquid-like properties and LLPS 7 1.2.3 Thermodynamics of condensation 10 1.2.4 The problem of an equilibrium description of living systems 13 1.2.5 Towards active condensation 14 1.3 Actomyosin cortex self-organization 16 1.3.1 F-actin treadmilling and nucleation 17 1.3.2 N-WASP and Arp2/3 regulation 18 1.3.3 Multivalent interactions in condensation of transmembrane receptors and actin regulators 22 1.3.4 Cortex activation in C. elegans 23 2 Aims 25 3 Results 26 3.1 C. elegans cortical activation begins at fertilization 26 3.1.1 C. elegans oocytes as an ex utero model for cortex self-organization 27 3.2 WSP-1, Arp2/3 and F-actin form dynamic multicomponent phases 32 3.2.1 Capping proteins outcompete Formin in WSP-1 Arp2/3 puncta preventing F-actin elongation 32 3.2.2 WSP-1 and Arp2/3 are required for punctate F-actin formation and dynamics 34 3.2.3 Summary of the characterization of cortical activation 34 3.3 Establishment of systematic phase portrait analysis for multicomponent clusters 36 3.3.1 Non-equilibrium features of the multicomponent puncta 36 3.3.2 Recording intensity traces of multicomponent cluster over time 37 3.3.3 Probability flux of composition in the phase portrait show a closed cycle 38 3.3.4 WSP-1 F-actin puncta have a preferred joint concentration 38 3.3.5 The phase portrait is robust to cell-to-cell noise 41 3.3.6 Choosing the appropriate bin size 41 3.4 Existence of a tuned critical size and signatures of active condensation 45 3.4.1 Growth rate dependence on internal composition 45 3.4.2 Stoichiometric growth laws of WSP-1 F-actin clusters 47 3.4.3 Estimation of WSP-1 cluster critical size in vivo 47 3.4.4 Theoretical description of WSP-1 and F-actin interactions in regulating puncta dynamics 48 3.4.5 Summary of 2D phase portrait findings 52 3.5 Towards three dimensional phase portrait analysis of the reaction network 54 3.6 Initial assessment of the compartment’s external environment 54 3.7 Identification of modulators of puncta dynamics 56 3.7.1 CDC-42 controls cortical levels of WSP-1 56 3.7.2 RHO-1 and Formin CYK-1 are not involved in WSP-1 F-actin condensate dynamics 58 3.7.3 WSP-1 and Arp2/3 dynamics are independent of NCK-1 and VAB-1 58 3.7.4 Arp2/3 regulates condensate dynamics 60 3.8 Summary of perturbations 63 4 Conclusions and outlook 64 4.1 Concluding remarks 64 4.2 Discussion 66 4.3 Future directions 67 4.3.1 Realizing the full potential of the phase portraits in identifying biochemical interactions 67 4.3.2 Resolving the ultrastructure of condensates . 70 4.3.3 Further investigation of the biological function 71 4.3.4 Applying full-dynamic data acquisition to other membraneless organelles 71 5 Materials and Methods 72 5.1 C.elegans maintenance and strains 72 5.2 Sample preparation 72 5.2.1 In utero imaging 72 5.2.2 Oocyte imaging 73 5.2.3 C.elegans HaloTag staining 73 5.2.4 Oocyte chemical inhibitor treatments 73 5.3 RNAi Feeding 73 5.4 Microscopy 73 5.4.1 Spinning disk microscopy 73 5.4.2 SIM-TIRF microscopy 74 5.5 TIRF microscopy 74 5.6 Phase portrait analysis pipeline 74 5.7 Kymographs 7

    Decontamination and Ecological Restoration Performance of a Bioretention Cell-Microbial Fuel Cell under Multiple-Antibiotics Stress

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    Antibiotics are refractory pollutants that have been widely found in various environmental media such as soil and surface water. Existing sewage treatments perform poorly at preventing antibiotics in urban sewage from polluting natural environments. In this study, we designed a bioelectrically enhanced bioretention cell system (bioretention cell-microbial fuel cell, BRC-MFC) that utilizes the unique structure of the BRC system to improve the removal of sewage antibiotics. This new system can efficiently remove antibiotics by using a synergy of plant absorption, filler adsorption, filler filtration and microbial degradation. To study the influences of multiple-antibiotics stress on the decontamination performance of BRC-MFC, ofloxacin (OFLX) and tetracycline (TC) were selected as target antibiotics, and five BRC-MFCs were built to treat sewage containing antibiotics of different concentrations. The concentrations of pollutant in the influent and effluent were measured and the pollutant removal performance of BRC-MFC was studied. The diversity of rhizosphere microorganisms and the abundance of denitrifying functional genes were analyzed. Experimental results showed that over 90% of OFLX and TC in each BRC-MFC were removed, with the removal rates positively correlating with the concentration of antibiotics. In addition, the removal rates of chemical oxygen demand (COD) in BRC-MFC were both over 90%, while the removal rate of total nitrogen (TN) was around 70%. Meanwhile, antibiotics could significantly improve the removal of ammonia nitrogen (NH4+-N, p < 0.01). The microbial richness decreased, and we found that combined antibiotic stress on microorganisms was stronger than single antibiotic stress. The abundance of denitrifying functional genes was reduced by antibiotic stress. The results of this study provide reference values for other projects focusing on removing various antibiotics from domestic sewage using BRC-MFC

    Mucinous cystadenocarcinoma of the ovary in a 14-year-old girl: a case report and literature review

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    Abstract Background Ovarian epithelial tumors are common in adults, and their peak incidence of onset is over 40 years of age. In children, most ovarian tumors are germ cell-derived, whereas epithelial tumors are rare and mostly benign. Case presentation This report describes a case of a 14-year-old Chinese girl with ovarian mucinous cystadenocarcinoma. She was admitted with a small amount of bloody vaginal discharge during the past month. Magnetic resonance imaging of the abdomen and pelvis showed a large solid cystic mass lesion in the left ovary. Tumor marker levels were within normal limits ( CA-125: 22.3 U/mL, HE4: 28.5 pmol/L, HCG: < 1.20 mIU/ml, AFP: 3.3 ng/ml, CEA: 2.2 ng/ml, CA19-9: < 2.0 U/mL). Laparoscopic exploration revealed a large left ovarian tumor. The patient underwent left salpingo-oophorectomy, and showed no significant issues during follow-up, as well as no evidence of recurrence or metastasis. Conclusions We report the first pediatric case of ovarian mucinous cystadenocarcinoma in China. Given the scarcity of reports addressing the clinical management of this condition, the present study provides a useful contribution to its further understanding in light of developing future treatment strategies

    Cumulative network-meta-analyses, practice guidelines and actual prescriptions of drug treatments for postmenopausal osteoporosis: a study protocol for cumulative network meta-analyses and meta-epidemiological study

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    Introduction: Cumulative network meta-analysis (NMA) is a method to provide a global comparison of multiple treatments with real-time update to evidence users. Several studies investigated the ranking of cumulative NMA and the recommendations of practice guidelines. However, to the best of our knowledge, no study has evaluated the cumulative NMA ranking and prescription patterns. Here, we present a protocol for a meta-epidemiological investigation to compare the results of cumulative NMA with the recommendations in postmenopausal osteoporosis practice guidelines and with the actual prescriptions. Method and analysis: We will use the data of primary trials from the upcoming postmenopausal osteoporosis clinical practice guideline of the Endocrine Society. We will conduct cumulative NMA using all eligible trials and generate hierarchy of treatment rankings by using the surface under the cumulative ranking curve. We will search practice guidelines in relevant society websites. Two review authors will extract the practice recommendations. We will use data from the Medical Expenditures Panel Survey, a US representative sample of the non-institutionalised population, to determine the prescription patterns. Ethics and dissemination: Because all data will be retrieved from public databases, institutional review board approval is not required. We will publish our findings in a peer-reviewed journal and present key findings at conferences. Trial registration number: UMIN000031894: Pre-results
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