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Eps15 (epidermal growth factor receptor pathway substrate 15) homology domain-containing proteins (EHDs) comprise a family of eukaryotic dynamin-related ATPases that participate in various endocytic membrane trafficking pathways. Dysregulation of EHDs function has been implicated in various diseases, including cancer. The lack of small molecule inhibitors which acutely target individual EHD members has hampered progress in dissecting their detailed cellular membrane trafficking pathways and their function during disease. Here, we established a Malachite green-based assay compatible with high throughput screening to monitor the liposome-stimulated ATPase of EHD4. In this way, we identified a drug-like molecule that inhibited EHD4’s liposome-stimulated ATPase activity. Structure activity relationship (SAR) studies indicated sites of preferred substitutions for more potent inhibitor synthesis. Moreover, the assay optimization in this work can be applied to other dynamin family members showing a weak and liposome-dependent nucleotide hydrolysis activity.

MACC1 (Metastasis Associated in Colon Cancer 1) is a key driver and prognostic biomarker for cancer progression and metastasis in a large variety of solid tumor types, particularly colorectal cancer (CRC). However, no MACC1 inhibitors have been identified yet. Therefore, we aimed to target MACC1 expression using a luciferase reporter-based high-throughput screening with the ChemBioNet library of more than 30,000 compounds. The small molecules lovastatin and rottlerin emerged as the most potent MACC1 transcriptional inhibitors. They remarkably inhibited MACC1 promoter activity and expression, resulting in reduced cell motility. Lovastatin impaired the binding of the transcription factors c-Jun and Sp1 to the MACC1 promoter, thereby inhibiting MACC1 transcription. Most importantly, in CRC-xenografted mice, lovastatin and rottlerin restricted MACC1 expression and liver metastasis. This is-to the best of our knowledge-the first identification of inhibitors restricting cancer progression and metastasis via the novel target MACC1. This drug repositioning might be of therapeutic value for CRC patients.

Microglia are the immune effector cells of the central nervous system (CNS) and react to pathologic events with a complex process including the release of nitric oxide (NO). NO is a free radical, which is toxic for all cells at high concentrations. To target an exaggerated NO release, we tested a library of 16 544 chemical compounds for their effect on lipopolysaccharide (LPS)-induced NO release in cell line and primary neonatal microglia. We identified a compound (C1) which significantly reduced NO release in a dose-dependent manner, with a low IC 50 (252 nM) and no toxic side effects in vitro or in vivo . Target finding strategies such as in silico modelling and mass spectroscopy hint towards a direct interaction between C1 and the nitric oxide synthase making C1 a great candidate for specific intra-cellular interaction with the NO producing machinery.

Lysophosphatidic acid (LPA) species in the extracellular environment induce downstream signaling six different G protein-coupled receptors (LPAR1-6). These signaling cascades are essential for normal brain development and function of the nervous system. However, in response to acute or chronic central nervous system (CNS) damage, LPA levels increase and aberrant signaling events can counteract brain function. Under neuro-inflammatory conditions signaling along the LPA/LPAR5 axis induces a potentially neurotoxic microglia phenotype indicating the need for new pharmacological intervention strategies. Therefore, we compared the effects of two novel small-molecule LPAR5 antagonists on LPA-induced polarization parameters of the BV-2 microglia cell line. AS2717638 is a selective piperidine-based LPAR5 antagonist (IC 0.038 μM) while compound 3 is a diphenylpyrazole derivative with an IC concentration of 0.7 μM in BV-2 cells. Both antagonists compromised cell viability, however, at concentrations above their IC concentrations. Both inhibitors blunted LPA-induced phosphorylation of STAT1 and STAT3, p65, and c-Jun and consequently reduced the secretion of pro-inflammatory cyto-/chemokines (IL-6, TNFα, IL-1β, CXCL10, CXCL2, and CCL5) at non-toxic concentrations. Both compounds modulated the expression of intracellular (COX-2 and Arg1) and plasma membrane-located (CD40, CD86, and CD206) polarization markers yet only AS2717638 attenuated the neurotoxic potential of LPA-activated BV-2 cell-conditioned medium towards CATH.a neurons. Our findings from the present study suggest that the two LPAR5 antagonists represent valuable pharmacological tools to interfere with LPA-induced pro-inflammatory signaling cascades in microglia.

The authors developed small-molecule inhibitors of STOML3 oligomerization, a membrane protein that interacts with mechanosensitive ion channels, such as Piezo2. One of these molecules was effective in silencing touch receptors and reversed touch-evoked pain associated with nerve injury or diabetic neuropathy. The skin is equipped with specialized mechanoreceptors that allow the perception of the slightest brush. Indeed, some mechanoreceptors can detect even nanometer-scale movements. Movement is transformed into electrical signals via the gating of mechanically activated ion channels at sensory endings in the skin. The sensitivity of Piezo mechanically gated ion channels is controlled by stomatin-like protein-3 (STOML3), which is required for normal mechanoreceptor function. Here we identify small-molecule inhibitors of STOML3 oligomerization that reversibly reduce the sensitivity of mechanically gated currents in sensory neurons and silence mechanoreceptors in vivo . STOML3 inhibitors in the skin also reversibly attenuate fine touch perception in normal mice. Under pathophysiological conditions following nerve injury or diabetic neuropathy, the slightest touch can produce pain, and here STOML3 inhibitors can reverse mechanical hypersensitivity. Thus, small molecules applied locally to the skin can be used to modulate touch and may represent peripherally available drugs to treat tactile-driven pain following neuropathy.

The SRP-Sec61 targeting/translocation pathway of eukaryotic cells targets nascent protein chains to the membrane of the endoplasmic reticulum. Using this machinery, secretory proteins are translocated across this membrane whereas membrane proteins are integrated into the lipid bilayer. One of the key players of the pathway is the protein-conducting Sec61 (translocon) complex of the endoplasmic reticulum. The Sec61 complex has no enzymatic activity, is expressed only intracellularly and is difficult to purify and to reconstitute. Screening for small molecule inhibitors impairing its functions is thus notoriously difficult. Such inhibitors may not only be valuable tools for cell biology, they may also represent novel anti-tumor drugs. Here we have developed a two-step, sequential screening assay for inhibitors of the whole SRP-Sec61 targeting/translocation pathway which might include molecules affecting Sec61 complex functions. The resulting hit compounds were analyzed using a whole cell biosynthesis assay and a cell free transcription/translation/translocation assay. Using this methodology, we identified novel compounds inhibiting this pathway. Following structure-based back screening, one of these substances was analyzed in more detail and we could show that it indeed impairs translocation at the level of the Sec61 complex. A slightly modified methodology may be used in the future to screen for substances affecting SecYEG, the bacterial ortholog of the Sec61 complex in order to derive novel antibiotic drugs.

Background The pathogenesis of contact dermatitis, a common inflammatory skin disease with limited treatment options, is held to be driven by inflammasome activation induced by allergens and irritants. We here aim to identify inflammasome‐targeting treatment strategies for irritant contact dermatitis. Methods A high content screen with 41,184 small molecules was performed using fluorescent Apoptosis associated speck‐like protein containing a CARD (ASC) speck formation as a readout for inflammasome activation. Hit compounds were validated for inhibition of interleukin (IL)‐1β secretion. Of these, the approved thiuramdisulfide derivative disulfiram was selected and tested in a patch test model of irritant contact dermatitis in 25 healthy volunteers. Topical application of disulfiram, mometasone or vehicle was followed by application of sodiumdodecylsulfate (SDS) for 24 h each. Eczema induction was quantified by mexameter and laser speckle imaging. Corneocyte sampling of lesional skin was performed to assess inflammasome‐mediated cytokines IL‐1β and IL‐18. Results Disulfiram induced a dose‐dependent inhibition of ASC speck formation and IL‐1β release in cellular assays in vitro. In vivo, treatment with disulfiram, but not with vehicle and less mometasone, inhibited SDS‐induced eczema. This was demonstrated by significantly lower erythema and total perfusion values assessed by mexameter and laser speckle imaging for disulfiram compared to vehicle (p < 0.001) and/or mometasone (p < 0.001). Also, corneocyte IL‐18 levels were significantly reduced after application of disulfiram compared to vehicle (p < 0.001). Conclusion We show that disulfiram is a dose‐dependent inhibitor of inflammasome pathway activation in vitro and inhibitor of SDS‐induced eczema in vivo. Topical application of disulfiram represents a potential treatment option for irritant contact dermatitis.

Abstract Inhaled pharmacotherapies are promising treatment options for patients with pulmonary arterial hypertension (PAH), as they minimize extrapulmonary adverse effects. Recently, we developed a highly specific tryptophan hydroxylase 1 inhibitor (TPHi): TPT-004. We hypothesized that repetitive nose-only inhalation of TPT-004 alleviates PAH and pulmonary vascular remodeling in the Sugen 5416/hypoxia (SuHx) rat model. Male Sprague Dawley rats were divided into three groups: ConNx (control animals kept in room air during the study); SuHx+vehicle (rats injected with the VEGFR2 inhibitor SU5416 and then exposed to chronic hypoxia for 3 weeks, followed by 10 days recovery and subsequent 4 weeks of daily vehicle inhalations; and SuHx+TPHi (SuHx-exposed rats after recovery treated with daily inhalations of the TPH1 inhibitor, TPT-004, for 4 weeks). Closed-chest right–left heart catheterization and cardiac magnetic resonance imaging were performed in spontaneously breathing rats. Histological and mRNA-sequencing analyses were performed on lungs. SuHx-exposed rats had severe PAH, right ventricle (RV) hypertrophy, and RV dilation. In comparison with SuHx-exposed rats, TPHi-treated SuHx rats had significantly lower RV systolic pressure (67.25 vs. 51.47 mm Hg; P < 0.0001), normalized RV end-systolic volume (182.6 vs. 105.1 μl; P < 0.0001), and improved RV ejection fraction by cardiac magnetic resonance imaging (47.9 vs. 66.8%; P < 0.0001). Inhaled TPT-004 did not affect left ventricular (LV) end-diastolic or systemic blood pressure. TPT-004 therapy reversed pulmonary vascular remodeling and alveolar macrophage infiltration. RNA sequencing unraveled TPHi-induced changes in pulmonary gene expression: increased cell adhesion as well as reduced cell motility and migration; suppressed extracellular matrix remodeling; modulated immune response; and suppressed pulmonary vascular remodeling by means of modulating proliferation, apoptosis, and homeostasis. Taken together, TPT-004 is an effective therapeutic PAH agent that does not cause any hemodynamic adverse effects in rodents, and thus, should be tested further towards a clinical phase 1b/phase 2 study in patients with PAH.

Fragment-based screening has evolved as a remarkable approach within the drug discovery process both in the industry and academia. Fragment screening has become a more structure-based approach to inhibitor development, but also towards development of pathway-specific clinical probes. However, it is often witnessed that the availability, immediate and long-term, of a high quality fragment-screening library is still beyond the reach of most academic laboratories. Within iNEXT (Infrastructure for NMR, EM and X-rays for Translational research), a EU-funded Horizon 2020 program, a collection of 782 fragments were assembled utilizing the concept of “poised fragments” with the aim to facilitate downstream synthesis of ligands with high affinity by fragment ligation. Herein, we describe the analytical procedure to assess the quality of this purchased and assembled fragment library by NMR spectroscopy. This quality assessment requires buffer solubility screening, comparison with LC/MS quality control and is supported by state-of-the-art software for high throughput data acquisition and on-the-fly data analysis. Results from the analysis of the library are presented as a prototype of fragment progression through the quality control process.

The layout of multipurpose screening libraries must address criteria for the compounds such as novelty, diversity potential, innovative design, and last but not least synthetic tractability. While academic compound collections are often innovative, novel, and highly divers, synthesis of analogs or larger substance quantities is often hampered by complex multistep syntheses with low overall yields. In addition, covalently binding compounds and interaction motifs designed to bind metal ions were discriminated against by the paradigm that these interaction types must almost inevitably lead to toxic effects. We would like to challenge this hypothesis. The lack of such interactions could be a reason for frequent failure in the disclosure of hits for hitherto undruggable target proteins using commercially available screening collections. Thus, easily synthesizable screening candidates equipped to bind covalently to nucleophiles or to metalloenzymes by chelation are under-represented in public access screening libraries. Within this work, we present the synthesis and deposition of 88 compounds with five distinct functional classes, each of which features under-represented screening motifs, for example, metal ion complexation, reversible covalent binding, or halogen bonding. The collection includes acetohydrazides, acylhydrazones, propylene glycol ethers, 2-cyanoacetamides, and 2-cyanoacrylamides. The rational for the synthesis of most of the compounds was recently published by our group and is now supplemented by additional compounds reported here for the first time. The public access disposition enables academic research groups to collectively expand the druggable space and interdisciplinary collaborate within the scientific field. Graphical Abstract