Synthesis of siderophore-based conjugates to detect and treat bacterial infections

Publikation: Qualifikations-/Studienabschlussarbeit › Dissertation

Autoren

  • Kevin Ferreira

Organisationseinheiten

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Details

OriginalspracheEnglisch
QualifikationDoctor rerum naturalium
Gradverleihende Hochschule
Betreut von
  • Mark Brönstrup, Betreuer*in
Datum der Verleihung des Grades9 Apr. 2018
ErscheinungsortHannover
PublikationsstatusVeröffentlicht - 2018

Abstract

Trotz der Entwicklung neuartiger Antiinfektiva steigen Morbidität und Mortalität aufgrund von Infektionen, die durch multiresistente Bakterien verursacht werden, weiter an.[1] Dies betrifft insbesondere Infektionen, die durch Gram-negative Bakterien verursacht werden. Die Herausforderung bei der Findung neuer Antibiotika besteht darin zu verstehen, wie eine ausreichende Translokation bioaktiver Moleküle durch die Zellwand Gram-negativer Bakterien gewährleistet werden kann. Zudem besteht ein Mangel an verlässlichen und empfindlichen Methoden, die die Erkennung von Bakterien zu einem frühen Zeitpunkt von Infektionen ermöglichen, an welchem die Behandlung mit Antibiotika noch effektiv ist.[2] Eine Möglichkeit bakterielle Zellwände zu durchdringen besteht in der Nutzung von Konjugaten, um die Internalisierung des Wirkstoffs über spezifische bakterielle Transportsysteme zu erleichtern.[2] So ist beispielsweise Eisen ein aktiv transportierter Nährstoff, der für Bakterien essentiell ist. Stabile, aktiv internalisierte Eisen(III)-Siderophorkomplexe können durch die sogenannte „Trojanisches-Pferd-Strategie“ genutzt werden. Eine Reihe von Siderophorkonjugaten wurde synthetisiert. Diese Konjugate nehmen aktiv Bakterien ins Visier, mindern deren Wachstum und ermöglichten die Visualisierung bakterieller Infektionen. Diese Dissertation beschreibt die Synthese und strukturelle Charakterisierung verschiedener Siderophore und Konjugate. Ferner wurden die Markierung von Siderophoren und ihre antibiotischen Eigenschaften evaluiert. 20 Substanzen wurden gegen E. coli und P. aeruginosa getestet. Um die intrazelluläre Akkumulation solcher Konjugate zu quantifizieren wurde eine neue Methode angewandt, die auf dem fluoreszenz-aktivierenden Protein (Fluorogen Activating Protein, FAP) basiert. Damit wurde die Bestimmung der subzellulären Lokalisation der Malachitgrün-gekoppelten niedermolekularen Verbindungen ermöglicht. Die Nutzung des Prinzips des aktiven Targetings in Verbindung mit der beschriebenen DOTAM/Metall-Plattform sollte geeignet für die Entwicklung neuartiger Wirkstoffkonjugate sein, die verschiedene zelluläre Wirkungsweisen und –orte gegen Gram-negative Bakterien aufweisen. Design und Synthese neuartiger Siderophorkonjugate, sowohl mit BODIPY-Verbindungen als auch mit Ampicillin, Ciprofloxacin oder Sorangicin, deren Internalisierungs-Eigenschaften in dieser Dissertation maßgeblich dargestellt werden, repräsentieren einen Meilenstein bei der Verbesserung der Theranostik gegen Bakterien der ESKAPE-Gruppe.

Zitieren

Synthesis of siderophore-based conjugates to detect and treat bacterial infections. / Ferreira, Kevin.
Hannover, 2018. 169 S.

Publikation: Qualifikations-/Studienabschlussarbeit › Dissertation

Ferreira, K 2018, 'Synthesis of siderophore-based conjugates to detect and treat bacterial infections', Doctor rerum naturalium, Gottfried Wilhelm Leibniz Universität Hannover, Hannover. https://doi.org/10.15488/3571
Ferreira, K. (2018). Synthesis of siderophore-based conjugates to detect and treat bacterial infections. [Dissertation, Gottfried Wilhelm Leibniz Universität Hannover]. https://doi.org/10.15488/3571
Ferreira K. Synthesis of siderophore-based conjugates to detect and treat bacterial infections. Hannover, 2018. 169 S. doi: 10.15488/3571
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@phdthesis{40ddcd0a757947a09390d4b0b5c03b38,
title = "Synthesis of siderophore-based conjugates to detect and treat bacterial infections",
abstract = "Infections caused by multidrug-resistant Gram-negative bacteria result in significant mortality and morbidity worldwide despite the development of new anti-infective drugs.[1] The need for novel antibiotics is currently not met by R&D efforts, in particular in the area of infections caused by Gram-negative bacteria. One of the scientific needs is to understand how to assure a sufficient translocation of bioactive molecules across the Gram-negative cell wall. Another limitation is the lack of reliable and sensitive methods that permit the detection of bacteria at early stages of infections where antibiotic treatments would still be effective.[2] One possibility to improve bacterial penetration is to generate conjugates and facilitate compound delivery through specific bacterial transport systems.[2] For example, iron is an essential actively transported nutrient: ferric siderophore complexes are internalized via recognition from the outer membrane and actively transported inside of Gram-positive and Gram-negative bacteria. Such stable, internalized complexes can be exploited with a so-called Trojan horse strategy. A series of agents comprising siderophores that actively target bacteria, inhibit bacterial growth and demonstrate efficacy to visualize bacterial infections were synthesized. This thesis shows the synthesis and structural characterization of various siderophores and conjugates, followed by an investigation of the siderophoric, labelling and antibiotic properties of the molecules. Designed conjugates were characterized as Fe(III) chelating agents. Among a list of 20 tested molecules on E. coli and P. aeruginosa, the DOTAM/catechol scaffolds showed high siderophoric effects. To quantify the intracellular accumulation of such conjugates, a fluorogen activating protein-based approach (FAP) that allows the determination of the subcellular localization of malachite green dye-coupled small molecules was pursued. This system served to validate the efficiency of vehicles for bacterial penetration.[3] The use of active targeting principles attached to the described DOTAM/Metal platform is expected to be appropriate for the development of new drug conjugates that have different cellular targets and modes of action against Gram-negative bacteria. The design and synthesis of novel BODIPY but also ampicillin, ciprofloxacin and sorangicin siderophore conjugates with a crucial demonstration of internalization described in this thesis represents a milestone towards improved theranostics against bacteria of the ESKAPE panel.",
author = "Kevin Ferreira",
note = "Doctoral thesis",
year = "2018",
doi = "10.15488/3571",
language = "English",
school = "Leibniz University Hannover",

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Download

TY - BOOK

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AU - Ferreira, Kevin

N1 - Doctoral thesis

PY - 2018

Y1 - 2018

N2 - Infections caused by multidrug-resistant Gram-negative bacteria result in significant mortality and morbidity worldwide despite the development of new anti-infective drugs.[1] The need for novel antibiotics is currently not met by R&D efforts, in particular in the area of infections caused by Gram-negative bacteria. One of the scientific needs is to understand how to assure a sufficient translocation of bioactive molecules across the Gram-negative cell wall. Another limitation is the lack of reliable and sensitive methods that permit the detection of bacteria at early stages of infections where antibiotic treatments would still be effective.[2] One possibility to improve bacterial penetration is to generate conjugates and facilitate compound delivery through specific bacterial transport systems.[2] For example, iron is an essential actively transported nutrient: ferric siderophore complexes are internalized via recognition from the outer membrane and actively transported inside of Gram-positive and Gram-negative bacteria. Such stable, internalized complexes can be exploited with a so-called Trojan horse strategy. A series of agents comprising siderophores that actively target bacteria, inhibit bacterial growth and demonstrate efficacy to visualize bacterial infections were synthesized. This thesis shows the synthesis and structural characterization of various siderophores and conjugates, followed by an investigation of the siderophoric, labelling and antibiotic properties of the molecules. Designed conjugates were characterized as Fe(III) chelating agents. Among a list of 20 tested molecules on E. coli and P. aeruginosa, the DOTAM/catechol scaffolds showed high siderophoric effects. To quantify the intracellular accumulation of such conjugates, a fluorogen activating protein-based approach (FAP) that allows the determination of the subcellular localization of malachite green dye-coupled small molecules was pursued. This system served to validate the efficiency of vehicles for bacterial penetration.[3] The use of active targeting principles attached to the described DOTAM/Metal platform is expected to be appropriate for the development of new drug conjugates that have different cellular targets and modes of action against Gram-negative bacteria. The design and synthesis of novel BODIPY but also ampicillin, ciprofloxacin and sorangicin siderophore conjugates with a crucial demonstration of internalization described in this thesis represents a milestone towards improved theranostics against bacteria of the ESKAPE panel.

AB - Infections caused by multidrug-resistant Gram-negative bacteria result in significant mortality and morbidity worldwide despite the development of new anti-infective drugs.[1] The need for novel antibiotics is currently not met by R&D efforts, in particular in the area of infections caused by Gram-negative bacteria. One of the scientific needs is to understand how to assure a sufficient translocation of bioactive molecules across the Gram-negative cell wall. Another limitation is the lack of reliable and sensitive methods that permit the detection of bacteria at early stages of infections where antibiotic treatments would still be effective.[2] One possibility to improve bacterial penetration is to generate conjugates and facilitate compound delivery through specific bacterial transport systems.[2] For example, iron is an essential actively transported nutrient: ferric siderophore complexes are internalized via recognition from the outer membrane and actively transported inside of Gram-positive and Gram-negative bacteria. Such stable, internalized complexes can be exploited with a so-called Trojan horse strategy. A series of agents comprising siderophores that actively target bacteria, inhibit bacterial growth and demonstrate efficacy to visualize bacterial infections were synthesized. This thesis shows the synthesis and structural characterization of various siderophores and conjugates, followed by an investigation of the siderophoric, labelling and antibiotic properties of the molecules. Designed conjugates were characterized as Fe(III) chelating agents. Among a list of 20 tested molecules on E. coli and P. aeruginosa, the DOTAM/catechol scaffolds showed high siderophoric effects. To quantify the intracellular accumulation of such conjugates, a fluorogen activating protein-based approach (FAP) that allows the determination of the subcellular localization of malachite green dye-coupled small molecules was pursued. This system served to validate the efficiency of vehicles for bacterial penetration.[3] The use of active targeting principles attached to the described DOTAM/Metal platform is expected to be appropriate for the development of new drug conjugates that have different cellular targets and modes of action against Gram-negative bacteria. The design and synthesis of novel BODIPY but also ampicillin, ciprofloxacin and sorangicin siderophore conjugates with a crucial demonstration of internalization described in this thesis represents a milestone towards improved theranostics against bacteria of the ESKAPE panel.

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DO - 10.15488/3571

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