How to find targets for new magic bullets? Hans Georg Sahl IMMIP – Pharmazeutische Mikrobiologie, Universität Bonn The lasting combat – new antibiotics and bacterial resistance Introduction of novel antibiotic classes 1950 Aminoglycosides 1940 Penicillin 1952 Macrolides 1962 Quinolones 2000 Oxazolidinones 1935 Sulphonamides 1949 Tetracyclines 1930s 1940s 1950s 1960s 1970s 1942 Sulphonamide resistance 1950s -Lactamresistance 1961 MRSA 1972 Multiresistent Salmonella typhi Examples of bacterial resistance development 1958 1962 Glycopeptides Streptogramines 1968 Tetracycline resistance 2003 Lipopeptides 1980s 1986 VRE 1990s 2000s 1990s Fluoroquinolone resistance 2000s First resistances against linezolid and daptomycin 1997 Discovery of VISA 2002 VRSA ? Antibiotic Targets Approaches for the discovery of novel antibiotic classes Advantages - antibiotic activity Problems - Unspecific – toxicity - old or new ? - MoA: time consuming - overmining of actinobacteria Advantages - target specificity - automation, robotics - target structures > rational drug design - combinatorial chemistry Problems - Lack of antibiotic activity > uptake/efflux - Specific aspects of MiOs neglected: - Essentiality ? - What is a good target ? - How to combine the advantages and avoid the problems ? - How to find a good target ? Bacterial Cell Biology Novel Isolation and Screening Technology Cell Wall Biosynthesis in Staphylococci GlcNAc III MurNAc peptidoglycan C55-P PBPs P Pi cytoplasm II P P P P P P MraY P P UDP MurG UMP MurF P P UDP DdlA P P FemABX 5 x Gly-tRNA D-Ala + D-Ala D-Ala-D-Ala, ATP ATP I MurE, MurD, MurC MurB, MurA UDP- UDP UDP L-Lys, ATP D-Glu, ATP L-Ala, ATP NADPH PEP Antibiotics – Tools to study biological processes T ARG ETS O O L S Lipid II : A most relevant target • • Glyco(lipo)peptide Antibiotics Target sites on Lipid II - e.g.Vancomycin - Ramoplanin Lantibiotics Lantibiotics Defensins Ramoplanin - Nisin - Gallidermin - Mersacidin ● Defensins - Plectasin and related defence peptides bactoprenol Vancomycin Antibiotics – Tools in Bacterial Cell Biology Peptidoglycan Cell Division WTA PknB SleI PBP PBP VicK LytM UppP TagO FtsQ MurJ MraY FtsW FtsQ FtsL RodA TagA MurG FemX FemA FtsB FemB EzrA FtsZ MnaA ZapA MurE MurZ MurD MurC based on an idea by Maria Senn FtsA GlyRS MurF Model by Tanja Schneider FtsK MurB MurA GlmU GlmM GlmS Fruc-6-P Why are penicillins such good antibiotics? - Do we know how penicillin kills? Similarity in structure Penicillin peptidoglycan D-Alanyl-D-Alanin O O OH OH TP TG PBP2 O O N N S N R O N R O PBP2-GFP localisation untreated penicillin-treated Pinho & Errington, 2005 Antibiotics that target cell envelope structures re-sensitize MRSA to β-lactams WTA PG LTA cell division PBP2a murgocil → high functional interdependencies between the different cellular pathways → reset MRSA phenotype > re-sensitize resistant strains & restore antibiotic activity Schneider, Pinho & Roemer. Curr Opin Microbiol, 2013 Mann et al., ACS Chem Biol, 2013 Koyoma et al., PLoS One, 2013 An irresistible newcomer Teixobactin Eleftheria terrae (William Fowley, Norteastern University) Ling & Schneider et al., Nature, 2015 Mode of action model → strongly limits resistance development 128 Fold-change in MIC • binds to multiple targets • of different cell envelope pathways • highly conserved non-protein target structures 256 64 32 16 8 Teixobactin 4 Ofloxacin 2 1 producer E. terrae S. aureus 0,5 0 5 10 [days] 15 Time 20 25 Fluorescence based promotor-reporter fusions (…) P sGFP P yvqF vraS Activation of the CWSS by treatment with CW active agents Control – nothing added Van 10X MIC Control – Nal. Acid 10X MIC Oxa 10X MIC Control – Erythr 10X MIC What can we learn from antibiotics / natural products ? Bacteria cells have a high degree of of functional organization - not just a bag full of enzymes - target biosynthesis machines and impact on their coordinated function - physical cellular damage which cannot be managed by stress response sytems - have two or more targets and activities Prof. Dr. Tanja Schneider Hannah Ulm Anna Müller Daniela Münch Patrick Hardt Marvin Rausch Ina Bertholt Dr. Beate Henrichfreise Anna Klöckner Stefania de Benedetti Christian Otten Henrike Bühl Dr. Fabian Grein Daniela Nusser Nina Kuklinski Dr. Iulia Chiriac Dr. Miriam Wilmes Michaele Josten Christiane Szekat Inge Luhmer Becker Acknowledgement Staphylococci Chlamydia produce perform kill Antimicrobial Peptides - Defensins Cooperations Heike Brötz-Oesterhelt Alex Tossi, Yechiel Shai Andreas Peschel, Fritz Götz Arnie Bayer, Michael Yeaman Leendert Hamoen Bob Hancock - Lantibiotics - Lipopeptides - Glycopeptides Cell Wall Biosynthesis interfere with Funding Deutsche Forschungsgemeinschaft DFG- FOR 854 Research Ministry BMBF DZIF (German Center of Infection Research) European Union various projects
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