Photo-activatable drugs (PDs) are rapidly emerging as precision therapeutics across biomedical research, yet their potential in epilepsy treatment has remained understudied. Given that 30% of epilepsies are medically refractory, and anti-seizure medications often cause multi-organ side-effects, PDs could break new ground. Here, we evaluate light-switchable ion-channel blockers QAQ and CQAQ, and a newly developed caged propofol (CaP), in murine brain slices, and postsurgical brain tissue from patients with epilepsy or brain tumors. In mice, we show that QAQ/CQAQ reversibly suppress neuronal firing, while photo-activated CaP prolonged inhibitory post-synaptic currents and enhanced leak current. While QAQ caused identical effects in human tissue, CQAQ unexpectedly increased firing. Activated CaP robustly suppressed epileptiform activity across species. This work establishes CaP as a tool for neuroscience and disease-related studies. Our results highlight the necessity for early human model testing in biomedical research, and showcase photopharmacology as a potential powerful approach to control human epilepsy.

Proteolysis targeting chimeric small molecules (PROTACs) offer a strategy for degrading disease-associated proteins or controlling engineered protein tags fused to therapeutic proteins, like chimeric antigen receptors (CARs). New approaches are needed that allow spatiotemporal control of PROTAC activity, restricting degrader activity to targeted cells. Photopharmacology offers a solution by enabling light-mediated spatial control of drug action. Here, we synthesize photocaged and photoswitchable PROTAC molecules and test their regulation of proteins tagged with E. coli dihydrofolate reductase (eDHFR) in tumor and CAR-T cells. Several of the molecules are derived from triazole-linked trimethoprim-PROTACs (TMP-TACtz), that degrade eDHFR fused proteins at picomolar concentrations, show degradation in cells with low cereblon E3 ligase levels, and have little off-target effects. The photocleavable compound, TMP-TAC-PC yields the best light-mediated regulation of CAR T cell cytotoxicity and cytokine secretion. This work introduces photocontrolled, tag-directed degraders for controlling protein expression in tumor cells and CAR T cells. In this work authors demonstrate how photocontrolled tag-targeted degradation enables precise, spatiotemporal control of protein expression in tumor cells and CAR T cells, offering an esapproach for regulating engineered proteins with light.

Photolipids have emerged as attractive tools for the optical control of lipid functions. They often contain an azobenzene photoswitch that imparts a cis double-bond upon irradiation. Herein, we present the application of photoswitching to a lipidated natural product, the potent proteasome inhibitor cepafungin I. Several azobenzene-containing lipids were attached to the cyclopeptide core, yielding photoswitchable derivatives. Most notably, PhotoCep4 exhibited a 10-fold higher cellular potency in its light-induced cis-form, matching the potency of natural cepafungin I. The length of the photolipid tail and distal positioning of the azobenzene photoswitch with respect to the macrocycle is critical for this activity. In a proteome-wide experiment, light-triggered PhotoCep4 modulation showed high overlap with constitutively active cepafungin I. The mode of action was studied using crystallography and revealed an identical binding of the cyclopeptide in comparison to cepafungin I, suggesting that differences in their cellular activity originate from switching the tail structure. The photopharmacological approach described herein could be applicable to many other natural products as lipid conjugation is common and often necessary for potent activity. Such lipids are often introduced late in synthetic routes, enabling facile chemical modifications.

AMPA receptors (AMPARs) are the main drivers of excitatory glutamatergic transmission in the brain, central to synaptic plasticity, and are key drug targets. However, AMPARs are expressed in virtually every neuron in the central nervous system and are activated with complex temporal dynamics, making it difficult to determine their functional roles with sufficient precision. Here we describe a cell specific, light-controllable competitive antagonist for the AMPA receptor called MP-GluAblock that combines the temporal precision of a photo-switchable ligand with the spatial and cellular specificity of a genetically-encoded membrane-anchor protein. This tool could pave the way for controlling endogenous AMPARs in neural circuits with cellular, spatial, and temporal specificity.

Incorporating photoisomerizable moieties within drugs offers the possibility of rapid and reversible light-dependent switching between active and inactive configurations. Here, we developed a photoswitchable adenosine A3 receptor (A3R) agonist that confers optical control on this G protein-coupled receptor through noninvasive topical skin irradiation in an animal model of psoriasis. This was achieved by covalently bonding an adenosine-5 '-methyluronamide moiety to a diazocine photochrome, whose singular photoswitching properties facilitated repeated interconversion between a thermally stable, biologically inactive Z agonist form and a photoinduced, pharmacologically active E configuration. As a result, our photoswitchable agonist allowed the precise modulation of A3R function both in vitro and in vivo, which led to a clear light-controlled pharmacotherapeutic effect on mouse skin lesions. This breakthrough not only demonstrates the potential of diazocine photoswitches for in vivo photopharmacology but also paves the way for the development of new strategies for skin-related diseases that require localized and temporally controlled drug action.

Key words bioconjugation - electrophilic probe - oximes - KRAS

Hundreds of proteins determine the function of synapses, and synapses define the neuronal circuits that subserve myriad brain, cognitive, and behavioral functions. It is thus necessary to precisely manipulate specific proteins at specific sub-cellular locations and times to elucidate the roles of particular proteins and synapses in brain function. We developed PHOtochemically TArgeting Chimeras (PHOTACs) as a strategy to optically degrade specific proteins with high spatial and temporal precision. PHOTACs are small molecules that, upon wavelength-selective illumination, catalyze ubiquitylation and degradation of target proteins through endogenous proteasomes. Here, we describe the design and chemical properties of a PHOTAC that targets Ca2+/calmodulin-dependent protein kinase II alpha (CaMKIIα), which is abundant and crucial for the baseline synaptic function of excitatory neurons. We validate the PHOTAC strategy, showing that the CaMKIIα-PHOTAC is effective in mouse brain tissue. Light activation of CaMKIIα-PHOTAC removed CaMKIIα from regions of the mouse hippocampus only within 25 μm of the illuminated brain surface. The optically controlled degradation decreases synaptic function within minutes of light activation, measured by the light-initiated attenuation of evoked field excitatory postsynaptic potential (fEPSP) responses to physiological stimulation. The PHOTACs methodology should be broadly applicable to other key proteins implicated in synaptic function, especially for evaluating their precise roles in the maintenance of long-term potentiation and memory within subcellular dendritic domains.

Key words post-translational modification - pentosinane - advanced glycation end products

Key words Salvinorin - Reformatsky reaction - Robinson annulation - Hayashi conjugate addition

Translation is an elementary cellular process that involves a large number of factors interacting in a concerted fashion with the ribosome. Numerous natural products have emerged that interfere with the ribosomal function, such as puromycin, which mimics an aminoacyl tRNA and causes premature chain termination. Here, we introduce a photoswitchable version of puromycin that, in effect, puts translation under optical control. Our compound, termed puroswitch, features a diazocine that allows for reversible and nearly quantitative isomerization and pharmacological modulation. Its synthesis involves a new photoswitchable amino acid building block. Puroswitch shows little activity in the dark and becomes substantially more active and cytotoxic, in a graded fashion, upon irradiation with various wavelengths of visible light. In vitro translation assays confirm that puroswitch inhibits translation with a mechanism similar to that of puromycin itself. Once incorporated into nascent proteins, puroswitch reacts with standard puromycin antibodies, which allows for tracking de novo protein synthesis using western blots and immunohistochemistry. As a cell-permeable small molecule, puroswitch can be used for nascent proteome profiling in a variety of cell types, including primary mouse neurons. We envision puroswitch as a useful biochemical tool for the optical control of translation and for monitoring newly synthesized proteins in defined locations and at precise time points.