Optische Kontrolle der Insulinsekretion mit einem Inkretinschalter

Near-Infrared Light-Activatable Spherical Nucleic Acids for Conditional Control of Protein Activity

Optical control of protein activity represents a promising strategy for precise modulation of biological processes. We report rationally designed, aptamer-based spherical nucleic acids (SNAs) capable of noninvasive and programmable regulation of target protein activity by deep-tissue-penetrable near-infrared (NIR) light. The photoresponsive SNAs are constructed by integrating activatable aptamer modules onto the surface of upconversion nanoparticles. The SNAs remain inert but can be remotely reverted by NIR light irradiation to capture the target protein and thus function as an enzyme inhibitor, while introduction of antidote DNA could further reverse their inhibition functions. Furthermore, we demonstrate the potential of the SNAs as controllable anticoagulants for the NIR light-triggered regulation of thrombin function. Ultimately, the availability of diverse aptamers would allow the design to regulate the activities of various proteins in a programmable manner.

Photoswitchable Serotonins for Optical Control of the 5-HT2A Receptor

Serotonin receptors play central roles in neuromodulation and are critical drug targets for psychiatric disorders. Optical control of serotonin receptor subtypes has the potential to greatly enhance our understanding of the spatiotemporal dynamics of receptor function. While other neuromodulatory receptors have been successfully rendered photoswitchable, reversible photocontrol of serotonin receptors has not been achieved, representing a major gap in GPCR photopharmacology. Herein, we develop the first tools that allow for such control. Azo5HT-2 shows light-dependent 5-HT_2A R agonism, with greater activity in the cis-form. Based on docking and test compound analysis, we also develop photoswitchable orthogonal, remotely-tethered ligands (PORTLs). These BG-Azo5HTs provide rapid, reversible, and repeatable optical control following conjugation to SNAP-tagged 5-HT_2A R. Overall, this study provides a foundation for the broad extension of photopharmacology to the serotonin receptor family.

Hydrazone Photoswitches for Structural Modulation of Short Peptides

Molecules that undergo light-driven structural transformations constitute the core components in photoswitchable molecular systems and materials. Among various families of photoswitches, photochromic hydrazones have recently emerged as a novel class of photoswitches with superb properties, such as high photochemical conversion, spectral tunability, thermal stability, and fatigue resistance. Hydrazone photoswitches have been adopted in various adaptive materials at different length scales, however, their utilization for modulating biomolecules still has not been explored. Herein we present new hydrazone switches that can photomodulate the structures of short peptides. Systematic investigation on a set of hydrazone derivatives revealed that installation of the amide group does not significantly alter the photoswitching behaviors. Importantly, a hydrazone switch comprising an upper phenyl ring and a lower quinolinyl ring was effective for structural control of peptides. We anticipate that this work, as a new milestone in the research of hydrazone switches, will open a new avenue for structural and functional control of biomolecules.

Impact of Substitution Registry on the Receptor-Activation Profiles of Backbone-Modified Glucagon-like Peptide-1 Analogues

Family B G protein-coupled receptors play important physiological roles and possess large extracellular domains (ECDs) that aid in binding the long polypeptide hormones that are their natural agonists. We have previously shown that agonist analogues in which subsets of native α-amino acid residues are replaced with β-amino acid residues can retain activity while avoiding proteolytic degradation. This study focuses on eight new α/β analogues of glucagon-like peptide 1 (GLP-1) that each contain five α-to-β replacements in the C-terminal half of the peptide. This portion of GLP-1 is known to adopt an α-helical conformation and contact the ECD. All four registries of the αααβ backbone pattern were evaluated; previous work has shown that the αααβ pattern supports adoption of an α-helix-like conformation. Two α-to-β replacement formats were employed, one involving β3 homologues of the native residues replaced and the other involving a cyclic β residue. GLP-1R response was characterized in terms of stimulation of cAMP production and β-arrestin recruitment. Some of the backbone-modified GLP-1 analogues display biased agonism of the GLP-1R. This study helps to establish the scope of the α→β backbone modification strategy.

A Photoswitchable Agonist for the Histamine H3 Receptor, a Prototypic Family A G-Protein-Coupled Receptor

Spatiotemporal control over biochemical signaling processes involving G protein-coupled receptors (GPCRs) is highly desired for dissecting their complex intracellular signaling. We developed sixteen photoswitchable ligands for the human histamine H3 receptor (hH3 R). Upon illumination, key compound 65 decreases its affinity for the hH3 R by 8.5-fold and its potency in hH3 R-mediated Gi protein activation by over 20-fold, with the trans and cis isomer both acting as full agonist. In real-time two-electrode voltage clamp experiments in Xenopus oocytes, 65 shows rapid light-induced modulation of hH3 R activity. Ligand 65 shows good binding selectivity amongst the histamine receptor subfamily and has good photolytic stability. In all, 65 (VUF15000) is the first photoswitchable GPCR agonist confirmed to be modulated through its affinity and potency upon photoswitching while maintaining its intrinsic activity, rendering it a new chemical biology tool for spatiotemporal control of GPCR activation.