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Career Publications

24. O Thorn-Seshold*, J Meiring; Photocontrolling Microtubule Dynamics with Photoswitchable Chemical Reagents.
ChemRxiv 14424176, 2021.
Optically controlling microtubules in vivo has gone from dream to reality in less than a decade. A range of photoswitchable chemical MT inhibitors from our group now allow sub-second temporal resolution and micron-scale spatial resolution of control over MT dynamics and MT-dependent processes.

However, there are still no guides for biologists wishing to establish and use photopharmaceutical-based assays, for any class of photopharmaceutical. Nor have the principles for robust assay design and mechanistic validation been unified and codified even for the synthetic chemistry community, and lack of reproducibility or transparent standards remains an issue in primary photopharmacology research.

This is a practical quick-start guide for biologists to use photoswitchable chemical reagents in cells, that describes (i) the basics of small molecule photoswitching and (ii) the special performance features, usage requirements, and limitations of chemical reagents. We then present (iii) assay validation and benchmarking workflows that can be greatly useful also to the synthetic chemistry community, including troubleshooting measures for avoiding common mistakes in cellular photopharmacology. We then outline (iv) the major photoswitchable MT inhibitors that are currently available; and give (v) workflows to establish cellular assays where they are used to optically control MT dynamics in a temporally reversible fashion with spatial specificity down to a single selected cell. The methods in this chapter are generally translatable to establishing and benchmarking assays with photopharmaceuticals for any protein target; and will equip both biologists and chemists to develop more robust photoswitchable reagents and to apply them in 3D culture and in vivo.

23. O Thorn-Seshold*, L Zeisel, J Felber; Dichalcogenide Prodrugs.
EP Patent application EP21167187.0, 2021.
A modular probe and prodrug system based on dichalcogenide redox chemistry.

22. L Gao, J Meiring, A Varady, I Ruider, C Heise, M Wranik, C Velasco, J Taylor, B Terni, J Standfuss, C Cabernard, A Llobet, M Steinmetz, A Bausch, M Distel, J Thorn-Seshold, A Akhmanova, and O Thorn-Seshold*;
In vivo photocontrol of microtubule dynamics and integrity, migration and mitosis, by the potent GFP-imaging-compatible photoswitchable reagents SBTubA4P and SBTub2M.
BioRxiv 2021,
The monster paper lands! Photopharmaceuticals in 2D cell culture can achieve target selectivity, potency, and spatiotemporal specificity through local illumination of globally-treated samples. But in 3D and in vivo, this has essentially not been reproduced. Here, we optimise a novel photoswitch for microtubule inhibition, which is fully compatible with multiplexed fluorescent protein imaging. Its mechanism of action is reproducible from cell culture through to 3D systems (organoids, whole brain explant) through to classic animal models (zebrafish, clawed frog): systemic SBTub treatment plus spatiotemporally-localised illuminations photocontrol microtubule dynamics, MT network architecture, cell migration and cell division with cellular precision and second-level resolution in vivo. These in vivo-capable reagents can rewire how we aim for high-precision cytoskeleton research in cargo transport, cell motility, cell division and development. Their design can alsobe extended to a range of other protein targets: bringing general in vivo photopharmacology one step closer to reality.

21. J Felber, L Zeisel, L Poczka, K Scholzen, S Busker, M Maier, U Theisen, C Brandstädter, K Becker, E Arnér, J Thorn-Seshold, and O Thorn-Seshold*;
Selective, modular probes for thioredoxins enabled by rational tuning of a unique disulfide structure motif.
ChemRxiv 2021,
Cyclic disulfides have a lot of potential for redox biology (!). Here we rationally design unique disulfides, invoking a combination of considerations for topology, thermodynamics, and kinetics. These give the only disulfide-based probes that can resist the cellular monothiol background; and they proved to be selectively triggered by the central redox effector protein, thioredoxin (Trx). The methodology in this paper forms the basis for our longterm project on redox biology.

20. L Gao, J Meiring, C Heise, A Rai, A Müller-Deku, A Akhmanova, J Thorn-Seshold, and O Thorn-Seshold*;
Photoswitchable epothilone-based microtubule stabilisers allow GFP-imaging-compatible, optical control over the microtubule cytoskeleton.
BioRxiv 2021,
Epothilone and Taxol, C=C photoswitches both new and old: here, we bring the GFP-orthogonal azobenzene isostere styrylthiazole (ST) into photopharmacology. The nanomolar-potent STEpo reagents are microtubule photoswitches with micron-precise-targeting and intriguing potential towards in vivo applications.

19. A Sailer, J Meiring, C Heise, L Pettersson, A Akhmanova, J Thorn-Seshold, and O Thorn-Seshold*; Pyrrole hemithioindigo antimitotics with near-quantitative bidirectional photoswitching photocontrol cellular microtubule dynamics with single-cell precision.
ChemRxiv 2021,
Most photopharmaceuticals suffer background activity, as their photoswitching is incomplete. Our PHTubs are near-quantitatively-switchable reagents that deliver cell-precise real-time photocontrol over microtubule dynamics, cell cycle, and cell death, for high-precision cytoskeleton research. This is the first use of hemithioindigos for high-resolution control in live cell assays, and shows PHTs may be excellent scaffolds for a range of other biological targets.

18. O Thorn-Seshold*, J Felber, J Thorn-Seshold, L Zeisel; Disulfide prodrug compounds.
EP Patent application EP21163944.8, 2021.
A modular probe and prodrug system based on disulfide redox chemistry.

17. J Felber, L Poczka, S Busker, U Theisen, L Zeisel, M Maier, C Brandstädter, K Scholzen, K Becker, E Arnér, J Thorn-Seshold, and O Thorn-Seshold*;
Cyclic 5-membered disulfides are not selective substrates of thioredoxin reductase, but are opened nonspecifically by thiols.
ChemRxiv 2020,
Cyclic five-membered disulfides have been used as "TRFS" probes for thioredoxin reductase (TrxR), in inhibitor screening and disease analysis. We show that such papers may need retraction. These SS50 probes are nonspecifically reduced by a broad range of thiols and proteins, and are barely affected by TrxR inhibition or knockout. We show why misinterpretations have arisen, and we present an approach to better orient future redox research.

16. L Gao, J Meiring, Y Kraus, M Wranik, T Weinert, S Pritzl, R Bingham, E Ntouliou, K Jansen, N Olieric, J Standfüss, L Kapitein, T Lohmüller, J Ahlfeld, A Akhmanova, M Steinmetz, and O Thorn-Seshold*;
A robust, GFP-orthogonal photoswitchable inhibitor scaffold extends optical control over the microtubule cytoskeleton.
Cell Chemical Biology 2021, 28, 1; highlighted in SynFacts.
It's no use photoswitching if you can't see what you're doing, or if the switch falls apart while you use it. These heterostilbene SBTubs were developed to leave GFP/YFP imaging channels free, and also resist in vivo metabolism. They allow exquisitely orthogonal photocontrol of cellular microtubule dynamics with minimal crosstalk/bleaching.

15. A Müller-Deku, J Meiring, K Loy, Y Kraus, C Heise, R Bingham, K Jansen, X Qu, F Bartolini, L Kapitein, A Akhmanova, J Ahlfeld, D Trauner, O Thorn-Seshold*; Photoswitchable paclitaxel-based microtubule stabilisers allow optical control over the microtubule cytoskeleton.
Nature Communications 2020, 11, 4640.
These AzTax reagents (azobenzene-extended taxols) are the first photoswitchable microtubule stabilisers. They enable cellularly- and subcellularly-specific photocontrol of MT polymerisation dynamics, incl. in primary neurons.

14. U Theisen, A Ernst, R Heyne, T Ring, O Thorn-Seshold, R Köster; Microtubules and motor proteins support zebrafish neuronal migration by directing cargo.
Journal of Cell Biology 2020, 219, e201908040.
Not only motile cell types but also neurons require dynamic MTs during motion. Spatiotemporally precise inhibition of their MTs with PST-1 links MT-based protein relocalisation to migration speed and directionality.

13. M Borowiak, F Küllmer, F Gegenfurtner, S Peil, V Nasufovic, S Zahler, O Thorn-Seshold, D Trauner, H-D Arndt; Optical manipulation of F-actin with photoswitchable small molecules.
Journal of the American Chemical Society 2020, 142, 9240.
These OptoJasps (azobenzene-extended jasplakinolides) are the first photoswitchable inhibitors for actin dynamics. They enable cellularly-targeted modulation of cell motility and other actin-dependent processes.

12. Y Kraus#, C Glas#, B Melzer, L Gao, C Heise, M Preuße, J Ahlfeld, F Bracher, O Thorn-Seshold*; Isoquinoline-based biaryls as a robust scaffold for microtubule inhibitors.
European Journal of Medicinal Chemistry 2020, 186, 111865.
Colchicinoids have two aryl blades separated by a bridge that is often metabolically or photochemically labile. These IQTub biaryls are highly robust; easy to make and diversify; and are potent druglike cellular binders.

11. A Sailer, F Ermer, Y Kraus, R Bingham, F Lutter, J Ahlfeld and O Thorn-Seshold*; Potent hemithioindigo-based antimitotics photocontrol the microtubule cytoskeleton in cellulo.
Beilstein Journal of Organic Chemistry 2020, 16, 125.
Improving on our first generation photoswitchable microtubule inhibitor HTIs, these HITubs are mid-nanomolar cell-active photoswitchable tubulin binders with all-visible-light switching, illustrating the potential of the HTI scaffold for cell biology.

10. A Kopf, J Renkawitz, R Hauschild, I Girkontaite, K Tedford, J Merrin, O Thorn-Seshold, D Trauner, H Häcker, K-D Fischer, E Kiermaier and M Sixt; Microtubules control cellular shape and coherence in amoeboid migrating cells.
Journal of Cell Biology 2020, 219, e201907154.
Using PSTs to spatiotemporally precisely inhibit MT dynamics in highly motile cells revealed the roles of MTs in maintaining cell shape and coordinating retractions with actomyosin.

9. M Bischof, S Olthoff, C Glas, O Thorn-Seshold, M Schaefer, K Hill; TRPV3 endogenously expressed in murine colonic epithelial cells is inhibited by the novel TRPV3 blocker 26E01.
Cell Calcium 2020, 102320.
26E01 was identified as a nontoxic blocker of TRPV3 currents in overexpression and native-expression cellular systems, that does not affect TRPV1, TRPV2, and TRPV4 channels.

8. O Thorn-Seshold*; Comment on “Photo-Controlled Reversible Microtubule Assembly”.
Angewandte Chemie 2020, 59, 7652.
Metabolically labile inhibitor-photoswitch attachment strategies and PAINS-like aggregation modulation can confound reagent design. This critique to Liu et al., ACIE 2018 highlights the danger of neglecting controls and SAR. Despite their followup showing that non-inhibitory analogues give identical effects (Liu et al., ACIE 2019) the initial paper is still not retracted (author response here).

7. A Sailer, F Ermer, Y Kraus, F Lutter, C Donau, M Bremerich, J Ahlfeld and O Thorn-Seshold*; Hemithioindigos for cellular photopharmacology: desymmetrised molecular switch scaffolds enabling design control over the isomer-dependency of potent antimitotic bioactivity.
ChemBioChem 2019, 20, 1305.
The understudied hemithioindigos have more attractive photoswitching than standard azobenzenes. These HOTubs are the first HTI-pharmacophore reagents to succeed in cell biology, and enable desymmetrised designs.

6. O Thorn-Seshold*, F. Bracher, B. Melzer; Isoquinoline biaryl compounds.
EP18207030, 2018.
IQTubs are diversifiable, metabolically robust isosteres for cis-stilbenoid bioactives.

5. A Singh, T Saha, I Begemann, A Ricker, H Nüsse, O Thorn-Seshold, J Klingauf, M Galic, M Matis; Polarized microtubule dynamics directs cell mechanics and coordinates forces during epithelial morphogenesis.
Nature Cell Biology 2018, 20, 1126.
Spatiotemporally resolved, reversible PST photoswitching elucidates the need for dynamic MTs in force generation to orient drosophila tissue development.

4. J Zenker, MD White, RM Templin, RG Parton, O Thorn-Seshold, S Bissiere, N Plachta; A microtubule-organizing center directing intracellular transport in the early mouse embryo.
Science 2017, 357, 925.
Spatiotemporally resolved, reversible PST photoswitching elucidates the location and origin of the non-centrosomal MT-organising system in the early stages of mammalian development.

3. K Eguchi, Z Taoufiq, O Thorn-Seshold, et al., T Takahashi; Wild-type monomeric α-synuclein can impair vesicle endocytosis and synaptic fidelity via tubulin polymerization at the calyx of Held.
The Journal of Neuroscience 2017, 37, 6043.
Temporally reversible MT inhibition applied using PST photoswitching contributes to understanding vesicle trafficking dynamics in neurons.

2. M Borowiak, et al., D Trauner*, O Thorn-Seshold*; Photoswitchable Inhibitors of Microtubule Dynamics Optically Control Mitosis and Cell Death.
Cell 2015, 162, 403.
Reversible photoswitching of PSTs allows bidirectionally reversible optical modulation of MT dynamics in live cells, and modifies cell division sequences during embryonic development.

1. O Thorn-Seshold*, M Borowiak, D Trauner, J Hasserodt; Azoaryls as Reversibly Modulatable Tubulin Inhibitors.
WO2015166295, 2014.
Reversibly photoswitchable isosteres of stilbenoid colchicine-mimic drugs ("PSTs") for in vitro and in vivo control of microtubule dynamics.

Studies & PhD

O Thorn-Seshold, M Vargas-Sanchez, S McKeon, J Hasserodt; A Robust, High-Sensitivity Stealth Probe for Peptidases. Chem. Comm. 2012, 48, 6253-6255.

J Hasserodt, O Thorn-Seshold; Fluorogenic Peptidase Substrate. WO2013045854, 2011.

D Konkolewicz, O Thorn-Seshold and A Gray-Weale; Models for randomly hyperbranched polymers: Theory and simulation. J. Chem. Phys. 2008, 129, 054901.

MM Bishop, LF Lindoy, M McPartlin, A Parkin, O Thorn-Seshold, P Turner; A systematic study of ligand intermolecular interactions in crystals of copper(II) complexes of bidentate guanidino derivatives. Polyhedron 2007, 26, (2), 415-429.

MM Bishop, SJ Coles, A Lee, LF Lindoy, A Parkin, O Thorn-Seshold, P Turner; A Structural Study of Tautomerism and Hydrogen-Bonding in Supramolecular Assemblies. Supramol. Chem. 2005, 17, (7), 567-578.

MM Bishop, LF Lindoy, O Thorn-Seshold, RO Piltz, P Turner; A Supramolecular Assembly Containing an Unusually Short N-H∙∙∙N Hydrogen Bond. J. Het. Chem. 2001, 38, (6), 1377-1382.