Development of a Potent and Selective G2A (GPR132) Agonist.

G protein-coupled receptor G2A was postulated to be a promising target for the development of new therapeutics in neuropathic pain, acute myeloid leukemia, and inflammation. However, there is still a lack of potent, selective, and drug-like G2A agonists to be used as a chemical tool or as the starting matter for the development of drugs. In this work, we present the discovery and structure-activity relationship elucidation of a new potent and selective G2A agonist scaffold. Systematic optimization resulted in (3-(pyridin-3-ylmethoxy)benzoyl)-d-phenylalanine (T-10418) exhibiting higher potency than the reference and natural ligand 9-HODE and high selectivity among G protein-coupled receptors. With its favorable activity, a clean selectivity profile, excellent solubility, and high metabolic stability, T-10418 qualifies as a pharmacological tool to investigate the effects of G2A activation.

Structural basis for the bi-specificity of USP25 and USP28 inhibitors.

The development of cancer therapeutics is often hindered by the fact that specific oncogenes cannot be directly pharmaceutically addressed. Targeting deubiquitylases that stabilize these oncogenes provides a promising alternative. USP28 and USP25 have been identified as such target deubiquitylases, and several small-molecule inhibitors indiscriminately inhibiting both enzymes have been developed. To obtain insights into their mode of inhibition, we structurally and functionally characterized USP28 in the presence of the three different inhibitors AZ1, Vismodegib and FT206. The compounds bind into a common pocket acting as a molecular sink. Our analysis provides an explanation why the two enzymes are inhibited with similar potency while other deubiquitylases are not affected. Furthermore, a key glutamate residue at position 366/373 in USP28/USP25 plays a central structural role for pocket stability and thereby for inhibition and activity. Obstructing the inhibitor-binding pocket by mutation of this glutamate may provide a tool to accelerate future drug development efforts for selective inhibitors of either USP28 or USP25 targeting distinct binding pockets.

Generation of human excitatory forebrain neurons by cooperative binding of proneural NGN2 and homeobox factor EMX1.

Generation of defined neuronal subtypes from human pluripotent stem cells remains a challenge. The proneural factor NGN2 has been shown to overcome experimental variability observed by morphogen-guided differentiation and directly converts pluripotent stem cells into neurons, but their cellular heterogeneity has not been investigated yet. Here, we found that NGN2 reproducibly produces three different kinds of excitatory neurons characterized by partial coactivation of other neurotransmitter programs. We explored two principle approaches to achieve more precise specification: prepatterning the chromatin landscape that NGN2 is exposed to and combining NGN2 with region-specific transcription factors. Unexpectedly, the chromatin context of regionalized neural progenitors only mildly altered genomic NGN2 binding and its transcriptional response and did not affect neurotransmitter specification. In contrast, coexpression of region-specific homeobox factors such as EMX1 resulted in drastic redistribution of NGN2 including recruitment to homeobox targets and resulted in glutamatergic neurons with silenced nonglutamatergic programs. These results provide the molecular basis for a blueprint for improved strategies for generating a plethora of defined neuronal subpopulations from pluripotent stem cells for therapeutic or disease-modeling purposes.

Photochemistry in Medicinal Chemistry and Chemical Biology.

Photochemistry has emerged as a transformative force in organic chemistry, significantly expanding the chemical space accessible for medicinal chemistry. Light-induced reactions enable the efficient synthesis of intricate organic structures and have found applications throughout the different stages of the drug discovery and development processes. Moreover, photochemical techniques provide innovative solutions in chemical biology, allowing precise spatiotemporal drug activation and targeted delivery. In this Perspective, we highlight the already numerous remarkable applications and the even more promising future of photochemistry in medicinal chemistry and chemical biology.

Discovery of a Small Molecule Activator of Slack (Kcnt1) Potassium Channels That Significantly Reduces Scratching in Mouse Models of Histamine-Independent and Chronic Itch.

Various disorders are accompanied by histamine-independent itching, which is often resistant to the currently available therapies. Here, it is reported that the pharmacological activation of Slack (Kcnt1, KNa1.1), a potassium channel highly expressed in itch-sensitive sensory neurons, has therapeutic potential for the treatment of itching. Based on the Slack-activating antipsychotic drug, loxapine, a series of new derivatives with improved pharmacodynamic and pharmacokinetic profiles is designed that enables to validate Slack as a pharmacological target in vivo. One of these new Slack activators, compound 6, exhibits negligible dopamine D2 and D3 receptor binding, unlike loxapine. Notably, compound 6 displays potent on-target antipruritic activity in multiple mouse models of acute histamine-independent and chronic itch without motor side effects. These properties make compound 6 a lead molecule for the development of new antipruritic therapies targeting Slack.

Dysregulation of alternative splicing in spinocerebellar ataxia type 1.

Spinocerebellar ataxia type 1 is caused by an expansion of the polyglutamine tract in ATAXIN-1. Ataxin-1 is broadly expressed throughout the brain and is involved in regulating gene expression. However, it is not yet known if mutant ataxin-1 can impact the regulation of alternative splicing events. We performed RNA sequencing in mouse models of spinocerebellar ataxia type 1 and identified that mutant ataxin-1 expression abnormally leads to diverse splicing events in the mouse cerebellum of spinocerebellar ataxia type 1. We found that the diverse splicing events occurred in a predominantly cell autonomous manner. A majority of the transcripts with misregulated alternative splicing events were previously unknown, thus allowing us to identify overall new biological pathways that are distinctive to those affected by differential gene expression in spinocerebellar ataxia type 1. We also provide evidence that the splicing factor Rbfox1 mediates the effect of mutant ataxin-1 on misregulated alternative splicing and that genetic manipulation of Rbfox1 expression modifies neurodegenerative phenotypes in a Drosophila model of spinocerebellar ataxia type 1 in vivo. Together, this study provides novel molecular mechanistic insight into the pathogenesis of spinocerebellar ataxia type 1 and identifies potential therapeutic strategies for spinocerebellar ataxia type 1.

Phenolate-Induced N-O Bond Formation versus TiemannType Rearrangement for the Synthesis of 3-Aminobenzisoxazoles and 2-Aminobenzoxazoles.

A novel oxadiazolone-based method for the synthesis of 3-aminobenzisoxazoles by N-O bond formation and of 2-aminobenzoxazoles through a Tiemann-type rearrangement has been developed. The synthesis of these two pharmaceutically relevant heterocycles was realized by an unexplored retrosynthetic disconnection using a cyclic nitrenoid precursor-based strategy. The selective formation of the two isomers was significantly influenced by steric and electronic effects of substituents. However, tetrabutylammonium chloride (TBACl) efficiently promoted the Tiemann-type rearrangement over N-O bond formation. Control experiments indicate that deprotonation of the phenol induces both rearrangements.

Identifying Disease Signatures in the Spinocerebellar Ataxia Type 1 Mouse Cortex.

The neurodegenerative disease spinocerebellar ataxia type 1 (SCA1) is known to lead to the progressive degeneration of specific neuronal populations, including cerebellar Purkinje cells (PCs), brainstem cranial nerve nuclei and inferior olive nuclei, and spinocerebellar tracts. The disease-causing protein ataxin-1 is fairly ubiquitously expressed throughout the brain and spinal cord, but most studies have primarily focused on the role of ataxin-1 in the cerebellum and brainstem. Therefore, the functions of ataxin-1 and the effects of SCA1 mutations in other brain regions including the cortex are not well-known. Here, we characterized pathology in the motor cortex of a SCA1 mouse model and performed RNA sequencing in this brain region to investigate the impact of mutant ataxin-1 towards transcriptomic alterations. We identified progressive cortical pathology and significant transcriptomic changes in the motor cortex of a SCA1 mouse model. We also identified progressive, region-specific, colocalization of p62 protein with mutant ataxin-1 aggregates in broad brain regions, but not the cerebellum or brainstem. A cross-regional comparison of the SCA1 cortical and cerebellar transcriptomic changes identified both common and unique gene expression changes between the two regions, including shared synaptic dysfunction and region-specific kinase regulation. These findings suggest that the cortex is progressively impacted via both shared and region-specific mechanisms in SCA1.

Synthesis and structure-activity relationships for some novel diflapolin derivatives with benzimidazole subunit.

A series of derivatives of the potent dual soluble epoxide hydrolase (sEH)/5-lipoxygenase-activating protein (FLAP) inhibitor diflapolin was designed, synthesised, and characterised. These novel compounds, which contain a benzimidazole subunit were evaluated for their inhibitory activity against sEH and FLAP. Molecular modelling tools were applied to analyse structure-activity relationships (SAR) on both targets and to predict solubility and gastrointestinal (GI) absorption. The most promising dual inhibitors of these series are 5a, 6b, and 6c.

The extra-cerebellar effects of spinocerebellar ataxia type 1 (SCA1): looking beyond the cerebellum.

Spinocerebellar ataxia type 1 (SCA1) is one of nine polyglutamine (polyQ) diseases and is characterized as an adult late-onset, progressive, dominantly inherited genetic disease. SCA1 is caused by an increase in the number of CAG repeats in the ATXN1 gene leading to an expanded polyQ tract in the ATAXIN-1 protein. ATAXIN-1 is broadly expressed throughout the brain. However, until recently, SCA1 research has primarily centered on the cerebellum, given the characteristic cerebellar Purkinje cell loss observed in patients, as well as the progressive motor deficits, including gait and limb incoordination, that SCA1 patients present with. There are, however, also other symptoms such as respiratory problems, cognitive defects and memory impairment, anxiety, and depression observed in SCA1 patients and mouse models, which indicate that there are extra-cerebellar effects of SCA1 that cannot be explained solely through changes in the cerebellar region of the brain alone. The existing gap between human and mouse model studies of extra-cerebellar regions in SCA1 makes it difficult to answer many important questions in the field. This review will cover both the cerebellar and extra-cerebellar effects of SCA1 and highlight the need for further investigations into the impact of mutant ATXN1 expression in these regions. This review will also discuss implications of extra-cerebellar effects not only for SCA1 but other neurodegenerative diseases showing diverse pathology as well.

Compilation and evaluation of a fatty acid mimetics screening library.

Focused compound libraries are well-established tools for hit identification in drug discovery and chemical probe development. We present the compilation and application of a focused screening library of fatty acid mimetics (FAMs), which are compounds designed to bind the orthosteric site of proteins that endogenously accommodate natural fatty acids and lipid metabolites. This set complies with chemical properties of FAM and was found suitable for use also in cellular setting. Several hits were retrieved in screening the focused library against diverse fatty acid binding targets including the enzymes soluble epoxide hydrolase (sEH) and leukotriene A4 hydrolase (LTA4H), the nuclear receptors peroxisome proliferator-activated receptor γ (PPARγ) and retinoid X receptor α (RXRα), the carrier proteins fatty acid binding protein 4 and 5 (FABP4 and FABP5), as well as the G-protein coupled receptors leukotriene B4 receptor 1 (BLT1) and free-fatty acid receptor 1 (FFAR1). Thus, the focused FAM library is suitable to obtain chemical starting matter for fatty acid binding proteins and provides a valuable extension to available screening collections.

Influence of statin treatment in a cohort of patients admitted for COVID-19.

Aims and objectives: Statins have been proposed as potentially useful agents for modulating the host response in COVID-19. However, solid evidence-based recommendations are still lacking. Our aim was to study the association between statin use and clinical outcomes in a large cohort of hospitalized patients with SARS-CoV-2 infection, as well as the specific consequences of chronic treatment withdrawal during hospital admission. Material and methods: Retrospective observational study including 2191 hospitalized patients with confirmed SARS-CoV-2 infection. Results: Mean age was 68.0±17.8 years and 597 (27.3%) patients died during follow-up. A total of 827 patients (37.7% of the whole sample), received chronic treatment with statins. Even though they underwent more frequent admissions in critical care units, chronic treatment with statins was not independently associated with all-cause mortality [HR 0.95 (0.72-1.25)]. During the whole hospital admission, 371 patients (16.9%) received at least one dose of statin. Although these patients had a significantly worse clinical profile, both treatment with statins during admission [HR 1.03 (0.78-1.35)] and withdrawal of chronic statin treatment [HR 1.01 (0.78-1.30)] showed a neutral effect in mortality. However, patients treated with statins presented more frequently hepatic cytolysis, rhabdomyolysis and thrombotic/hemorrhagic events. Conclusions: In this large cohort of hospitalized COVID-19 patients, statins were not independently associated with all-cause mortality during follow-up. Clinically relevant statin-associated adverse effects should be carefully monitored during hospital admission.

Antecedentes y objetivos: Se ha especulado que las estatinas pueden ser de utilidad en el tratamiento de pacientes con COVID-19, pero no existen evidencias clínicas sólidas. El objetivo de este trabajo es conocer su utilidad en una cohorte de gran tamaño de pacientes hospitalizados por COVID-19, así como si su retirada se asocia con un peor pronóstico. Material y métodos: Estudio retrospectivo observacional. Se incluyeron 2.191 pacientes hospitalizados con infección confirmada con SARS-CoV-2. Resultados: La edad media fue de 68,0 ± 17,8 años y fallecieron un total de 597 (27,3%) pacientes. Un total de 827 pacientes (37,7% de la muestra) estaban tratados previamente con estatinas. Aunque precisaron con mayor frecuencia de ingreso en camas de críticos, dicho grupo terapéutico no resultó un factor predictor independiente de muerte en el seguimiento [HR 0,95 (0,72-1,25)]. Un total de 371 pacientes (16,9%) recibió al menos una dosis de estatina durante el ingreso. A pesar de ser una población con un perfil clínico más desfavorable, tanto su uso [HR 1,03 (0,78-1,35)] como la suspensión durante el ingreso en pacientes que las recibían crónicamente [HR 1,01 (0,78-1,30)] presentaron un efecto neutro en la mortalidad. No obstante, el grupo con estatinas desarrolló con mayor frecuencia datos de citolisis hepática, rabdomiolisis y más eventos trombóticos y hemorrágicos. Conclusiones: En nuestra muestra, las estatinas no se asociaron de forma independiente a una menor mortalidad en pacientes con COVID-19. En aquellos pacientes que tengan indicación de recibirlas por su patología previa es necesario monitorizar estrechamente sus potenciales efectos adversos durante el ingreso hospitalario.

Exploring the Role of Posttranslational Modifications in Spinal and Bulbar Muscular Atrophy.

Spinal and Bulbar Muscular Atrophy (SBMA) is an X-linked adult-onset progressive neuromuscular disease that affects the spinal and bulbar motor neurons and skeletal muscles. SBMA is caused by expansion of polymorphic CAG trinucleotide repeats in the Androgen Receptor (AR) gene, resulting in expanded glutamine tract in the AR protein. Polyglutamine (polyQ) expansion renders the mutant AR protein toxic, resulting in the formation of mutant protein aggregates and cell death. This classifies SBMA as one of the nine known polyQ diseases. Like other polyQ disorders, the expansion of the polyQ tract in the AR protein is the main genetic cause of the disease; however, multiple other mechanisms besides the polyQ tract expansion also contribute to the SBMA disease pathophysiology. Posttranslational modifications (PTMs), including phosphorylation, acetylation, methylation, ubiquitination, and SUMOylation are a category of mechanisms by which the functionality of AR has been found to be significantly modulated and can alter the neurotoxicity of SBMA. This review summarizes the different PTMs and their effects in regulating the AR function and discusses their pathogenic or protective roles in context of SBMA. This review also includes the therapeutic approaches that target the PTMs of AR in an effort to reduce the mutant AR-mediated toxicity in SBMA.

Influencia del tratamiento con estatinas en una cohorte de pacientes ingresados por COVID-19 / Influence of statin treatment in a cohort of patients admitted for COVID-19

Antecedentes y objetivos:Se ha especulado que las estatinas pueden ser de utilidad en el tratamiento de pacientes con COVID-19, pero no existen evidencias clínicas sólidas. El objetivo de este trabajo es conocer su utilidad en una cohorte de gran tamaño de pacientes hospitalizados por COVID-19, así como si su retirada se asocia con un peor pronóstico.Material y métodos:Estudio retrospectivo observacional. Se incluyeron 2.191 pacientes hospitalizados con infección confirmada con SARS-CoV-2.Resultados:La edad media fue de 68,0 ± 17,8 años y fallecieron un total de 597 (27,3%) pacientes. Un total de 827 pacientes (37,7% de la muestra) estaban tratados previamente con estatinas. Aunque precisaron con mayor frecuencia de ingreso en camas de críticos, dicho grupo terapéutico no resultó un factor predictor independiente de muerte en el seguimiento [HR 0,95 (0,72-1,25)]. Un total de 371 pacientes (16,9%) recibió al menos una dosis de estatina durante el ingreso. A pesar de ser una población con un perfil clínico más desfavorable, tanto su uso [HR 1,03 (0,78-1,35)] como la suspensión durante el ingreso en pacientes que las recibían crónicamente [HR 1,01 (0,78-1,30)] presentaron un efecto neutro en la mortalidad. No obstante, el grupo con estatinas desarrolló con mayor frecuencia datos de citolisis hepática, rabdomiolisis y más eventos trombóticos y hemorrágicos.Conclusiones:En nuestra muestra, las estatinas no se asociaron de forma independiente a una menor mortalidad en pacientes con COVID-19. En aquellos pacientes que tengan indicación de recibirlas por su patología previa es necesario monitorizar estrechamente sus potenciales efectos adversos durante el ingreso hospitalario. (AU)

Aims and objectives:Statins have been proposed as potentially useful agents for modulating the host response in COVID-19. However, solid evidence-based recommendations are still lacking. Our aim was to study the association between statin use and clinical outcomes in a large cohort of hospitalized patients with SARS-CoV-2 infection, as well as the specific consequences of chronic treatment withdrawal during hospital admission.Material and methods:Retrospective observational study including 2191 hospitalized patients with confirmed SARS-CoV-2 infection.Results:Mean age was 68.0±17.8 years and 597 (27.3%) patients died during follow-up. A total of 827 patients (37.7% of the whole sample), received chronic treatment with statins. Even though they underwent more frequent admissions in critical care units, chronic treatment with statins was not independently associated with all-cause mortality [HR 0.95 (0.72-1.25)]. During the whole hospital admission, 371 patients (16.9%) received at least one dose of statin. Although these patients had a significantly worse clinical profile, both treatment with statins during admission [HR 1.03 (0.78-1.35)] and withdrawal of chronic statin treatment [HR 1.01 (0.78-1.30)] showed a neutral effect in mortality. However, patients treated with statins presented more frequently hepatic cytolysis, rhabdomyolysis and thrombotic/hemorrhagic events.Conclusions:In this large cohort of hospitalized COVID-19 patients, statins were not independently associated with all-cause mortality during follow-up. Clinically relevant statin-associated adverse effects should be carefully monitored during hospital admission. (AU)

Cascade Synthesis of Kinase-Privileged 3-Aminoindazoles via Intramolecular N-N Bond Formation.

3-Aminoindazoles are privileged scaffolds for bioactive drug-like molecules. In this study, a microwave-assisted cascade reaction for the synthesis of N-1 substituted 3-aminoindazoles with yields up to 81% has been developed. Starting from 3-(2-bromoaryl)-1,2,4-oxadiazol-5(4H)-ones, the reaction exhibits a broad substrate scope including anilines, aliphatic amines, and sulfonamides and bypasses selectivity issues between N-1 and 3-amino group. Furthermore, the Differential Scanning Fluorimetry screen of a kinase panel demonstrated the value of targeting N-1 substituted 3-aminoindazoles as kinase-biased fragments.

Development and Characterization of a Fluorescent Ligand for Leukotriene B4 Receptor 2 in Cells and Tissues.

The leukotriene B4 receptor 2 (BLT2) is a G-protein coupled receptor activated by 12(S)-hydroxyheptadeca-5Z,8E,10E-trienoic acid (12-HHT), which has been proposed as a promising therapeutic target for diabetic wound healing and gastrointestinal lesions. In this study, the rational design of a fluorescent probe based on the synthetic BLT2 agonist CAY10583 is described. The synthesis of several derivatives of CAY10583 coupled to fluorescein resulted in a traceable ligand suitable for different fluorescence-based techniques. An HTRF-based displacement assay (Tag-lite) on stably transfected CHO-K1 cells was developed to characterize binding properties of diverse BLT2 ligands. Highly specific binding to the BLT2 receptor was demonstrated in staining experiments on mouse skin tissue, and specific modulation of BLT2-induced cAMP signaling provided further evidence for receptor binding and ligand functionality. In conclusion, the fluorescent ligands developed in this study are suitable to investigate the pharmacology of BLT2 receptor ligands in a variety of assay systems.

Influence of statin treatment in a cohort of patients admitted for COVID-19. / Influencia del tratamiento con estatinas en una cohorte de pacientes ingresados por COVID-19.

AIMS AND OBJECTIVES: Statins have been proposed as potentially useful agents for modulating the host response in COVID-19. However, solid evidence-based recommendations are still lacking. Our aim was to study the association between statin use and clinical outcomes in a large cohort of hospitalized patients with SARS-CoV-2 infection, as well as the specific consequences of chronic treatment withdrawal during hospital admission. MATERIAL AND METHODS: Retrospective observational study including 2191 hospitalized patients with confirmed SARS-CoV-2 infection. RESULTS: Mean age was 68.0±17.8 years and 597 (27.3%) patients died during follow-up. A total of 827 patients (37.7% of the whole sample), received chronic treatment with statins. Even though they underwent more frequent admissions in critical care units, chronic treatment with statins was not independently associated with all-cause mortality [HR 0.95 (0.72-1.25)]. During the whole hospital admission, 371 patients (16.9%) received at least one dose of statin. Although these patients had a significantly worse clinical profile, both treatment with statins during admission [HR 1.03 (0.78-1.35)] and withdrawal of chronic statin treatment [HR 1.01 (0.78-1.30)] showed a neutral effect in mortality. However, patients treated with statins presented more frequently hepatic cytolysis, rhabdomyolysis and thrombotic/hemorrhagic events. CONCLUSIONS: In this large cohort of hospitalized COVID-19 patients, statins were not independently associated with all-cause mortality during follow-up. Clinically relevant statin-associated adverse effects should be carefully monitored during hospital admission.

Structure-Based Design of Dual Partial Peroxisome Proliferator-Activated Receptor γ Agonists/Soluble Epoxide Hydrolase Inhibitors.

Polypharmaceutical regimens often impair treatment of patients with metabolic syndrome (MetS), a complex disease cluster, including obesity, hypertension, heart disease, and type II diabetes. Simultaneous targeting of soluble epoxide hydrolase (sEH) and peroxisome proliferator-activated receptor γ (PPARγ) synergistically counteracted MetS in various in vivo models, and dual sEH inhibitors/PPARγ agonists hold great potential to reduce the problems associated with polypharmacy in the context of MetS. However, full activation of PPARγ leads to fluid retention associated with edema and weight gain, while partial PPARγ agonists do not have these drawbacks. In this study, we designed a dual partial PPARγ agonist/sEH inhibitor using a structure-guided approach. Exhaustive structure-activity relationship studies lead to the successful optimization of the designed lead. Crystal structures of one representative compound with both targets revealed potential points for optimization. The optimized compounds exhibited favorable metabolic stability, toxicity, selectivity, and desirable activity in adipocytes and macrophages.