This study describes 14 novel D2AAK1 derivatives exhibiting enhanced neuroprotective properties. These derivatives were tested for their inhibitory effects on AChE and MAO-B, as well as their effect on cell viability under normal conditions and under oxidative stress. D2AAK1 derivatives show strong cytoprotective effects, increasing cell viability by up to 80% under normal conditions and up to 60% under oxidative stress. These effects may involve modulation of MAPK p38 and Nrf2 pathway interactions, known to promote antioxidant and anti-apoptotic responses. In vivo studies indicated a beneficial effect of the tested derivative on memory processes in the novel object recognition test. These findings identify D2AAK1 derivatives as promising lead compounds for further development as potential treatments of memory deficits.

GPCR dimers and receptor mosaics are distinct pharmacological entities that can be targeted by specific ligands, including bivalent ligands, thus GPCR dimerization is a well-known concept. GPCR oligomerization can be studied with biochemical, biophysical, and computational methods. Here, we review classical and novel biochemical approaches to investigate this phenomenon. We discuss protomer co-expression, co-immunoprecipitation, heteromer-specific antibodies, proximity ligation assay, APEX2-MS proximity assay, receptor mutants and chimeras, radiation inactivation studies, cross-linking studies, and trans-complementation studies. For each approach, the basis of the technique is summarized, followed by an extensive list of its applications. This review is a comprehensive resource for biochemists and molecular biologists working in the field of GPCR oligomerization, as well as for scientists interested in GPCR drug design and discovery.

Castration-resistant prostate cancer (CRPC) remains a significant clinical challenge due to the ability of tumor cells to undergo intratumoral androgen synthesis, a process catalyzed by the CYP17A1 enzyme. The only CYP17A1 inhibitor available in therapy, abiraterone acetate, faces significant limitations due to its steroidal structure, which causes off-target effects and generates agonistic metabolites that paradoxically stimulate the androgen receptor (AR). This study presents the development of the D2AAK1M series, a novel class of non-steroidal potential CYP17A1 inhibitors based on a pyridine-piperidine scaffold. Through biomimetic design and molecular docking, we demonstrated that these compounds have the potential to coordinate the heme iron while achieving high shape complementarity within the catalytic pocket. In silico ADME profiling indicated superior physicochemical properties compared to abiraterone, including optimal lipophilicity, enhanced water solubility, and the potential to penetrate the blood-brain barrier for targeting CNS metastases. In vitro assay results correlated with a suggested mechanism, showing preferential cytotoxicity toward androgen-dependent LNCaP cells (AR+) while sparing AR-negative lines (DU145, PC3) and healthy human fibroblasts (BJ). Our compounds present a promising starting point for further development of non-steroidal CYP17A1 inhibitors.

Progress in understanding protein-ligand interactions is revolutionizing drug design, especially for G protein-coupled receptors (GPCRs), which are targets for 35% of marketed drugs.[1][1] The dopamine D2 receptor (D2R) represents a key drug target in schizophrenia and Parkinson’s disease.[2][2] While structural studies have clarified its interactions with classical ligands, the behavior of atypical, non-basic ligands like D2AAK2 remains unclear. Notably, D2AAK2 shows strong selectivity for D2R over the closely related D3R, despite identical binding pocket composition. Here, we present a cryo-EM structure of D2AAK2 bound to D2R, showing that aspartate 3.32 serves as the main anchoring point, even though the compound lacks a basic nitrogen atom. Using enhanced sampling molecular dynamics simulations and experimental approaches, we uncover a complex binding energy landscape. Simulations suggest that D2AAK2 receptor subtype selectivity between identical binding sites arises from different energy barriers for their conformational changes. Non-basic ligands offer advantages such as better brain penetration and improved pharmacokinetics.[3][3],[4][4] This study provides the first structural insights into a non-basic ligand targeting D2R, paving the way for developing more effective, selective drugs. ### Competing Interest Statement The authors have declared no competing interest. National Science Centre, 2017/27/B/NZ7/01767 Narodowa Agencja Wymiany Akademickiej, PANALLOS, BPN/BEK/2021/1/00408/U/00001 PRACE European Computing Infrastructure grants, MOLTRANSREC, NERVOMOLSIM Poznan Supercomputing and Networking Center, MOLTRANSREC Interdisciplinary Center for Mathematical and Computational Modeling in Warsaw, G85-948 Knut and Alice Wallenberg Foundation, KAW 2019.0130 Swedish Research Council, 2021-4186, 2025-06266, 2022-06725 Ministry of Economy, Industry and Competitiveness, SAF2014-57138-C2-1-R Xunta de Galicia Foundation for Polish Science, https://ror.org/048zd9m77 Tsinghua-Peking Center for Life Sciences Tsinghua University Beijing Frontier Research Center for Biological Structure Tsinghua University Initiative Scientific Research Program National Academic Infrastructure for Supercomputing in Sweden [1]: #ref-1 [2]: #ref-2 [3]: #ref-3 [4]: #ref-4

The global rise in life expectancy has been accompanied by a growing prevalence of neurodegenerative diseases, such as Alzheimer's disease (AD). These complex disorders arise from multiple pathogenic factors and biological pathways, necessitating the development of multi-target therapeutic strategies. D2AAK1, discovered by our group, has emerged as a promising candidate due to its cytoprotective, antioxidant, and procognitive properties. This study aimed to further elucidate the mechanisms underlying the action of D2AAK1 and its derivatives, with a focus on their potential for neuroprotection and cognitive enhancement. The effect of D2AAK1 on cell viability was evaluated under normal conditions and during H2O2-induced oxidative stress using the resazurin assay. p38 MAPK activity was measured through cell-based ELISA. mRNA expression was analyzed using a two-step quantitative PCR method, and enzymatic effects were assessed via photometric, fluorescence, and luminescence techniques. Behavioral studies in murine models were performed to investigate the influence of the compounds on memory processes. It was found that D2AAK1 and its derivatives significantly enhanced cell viability, with some derivatives exhibiting greater potency than D2AAK1. In vivo, one derivative notably improved memory performance and reversed scopolamine-induced memory impairment in the novel object recognition test in male Swiss mice. Mechanistic studies revealed that D2AAK1 increased the expression of cytoprotective proteins such as Bcl-2 and HO-1, while concurrently reducing the expression and activity of pro-apoptotic factors, including caspase-3, p38 MAPK, and MAO-B. These dual actions culminated in enhanced cellular resilience and viability, translating into improved cognitive outcomes. The findings suggest that D2AAK1 and its derivatives, through their multi-factor mechanism of action, hold promise as therapeutic agents for the treatment of neurodegenerative diseases.

Many drug discovery efforts have identified potentially promising molecules; however, a common limitation of these reports is the lack of further experimental confirmation of pharmacokinetic properties and behavioral effects of discovered compounds. In this study, we aim to address this limitation. Therefore, we build on our previous virtual screening campaign by synthesizing, analyzing in silico, and evaluating experimentally the SERAAK1 compound, which was initially identified as a ligand for 5-HT1A, 5-HT2A, and D2 receptors. Through these investigations, we discovered that SERAAK1 binds to the orthosteric pocket of the 5-HT2A receptor in a similar mechanism to that known for marketed antipsychotic medications. Molecular dynamics simulations revealed that the SERAAK1 compound remains stable in the orthosteric binding pocket of the 5-HT2A receptor. The determination of the ADMET parameters indicated the directions for further optimization of the compounds. In vivo studies demonstrated the anxiolytic and antidepressant properties of the SERAAK1 compound.

Alzheimer’s disease (AD) is a multi-factorial neurodegenerative disease with a complex pathomechanism that can be best treated with multi-target medications. Among the possible molecular targets involved in AD, acetylcholinesterase (AChE) and monoamine oxidase B (MAO-B) are well recognized because they control the neurotransmitters responsible for memory processes. This review discusses the current understanding of AD pathology, recent advances in AD treatment, and recent reports in the field of dual AChE/MAO-B inhibitors for treating AD. We provide a classification of dual inhibitors based on their chemical structure and describe active compounds belonging to, i.a., chalcones, coumarins, chromones, imines, and hydrazones. Special emphasis is given to the computer-aided strategies of dual inhibitors design, their structure–activity relationships, and their interactions with the molecular targets at the molecular level.

The synthesis of a new series of long-chain arylpiperazine as serotoninergic ligands (FG 1-18) is described. The combination of structural elements including heterocyclic nucleus, propyl chain, and 4,5-dihydrothiazol-2-ylphenylpiperazines leads to the preparation of different derivatives tested for their affinity toward 5-HT1A, 5-HT2A, and 5-HT2C receptors. The compounds with better affinity and selectivity binding profiles toward 5-HT1A and 5-HT2C (FG-1, FG-4, FG-5, FG-6, FG-7, FG-8, and FG-18) are selected for further in vivo assays to determine their functional activity. Finally, to rationalize the obtained results, molecular docking studies are performed. The results of pharmacological studies show that compounds FG-1, FG-5, FG-8, and FG-6 exert antidepressant-like effects, and FG-1, FG-18, FG-6, and FG-7 reveal also significant anxiolytic properties. Among the developed derivatives, the most promising compounds seem to be FG-1, which exhibit antidepressant, anxiolytic, and anticonvulsant properties, FG-7 and FG-18 that show features as anxiolytic combine to a pro-cognitive property and notable affinity and selectivity for 5-HT2C receptor, respectively.

Serotonin receptors, in particular 5-HT1A and 5-HT2A receptors, are important molecular targets for the central nervous system (CNS) disorders, such as schizophrenia, depression, anxiety disorders, memory deficits, and many others. Here, we present structural and pharmacological evaluation of a serotonin receptor ligand, SERAAK2, identified in a structure-based virtual screening campaign. Molecular docking studies revealed that SERAAK2 binds with its molecular targets via Asp3.32 as the main anchoring point, which is typical for orthosteric ligands of aminergic GPCRs. Molecular dynamics simulations confirmed the stability of the ligand binding poses in the studied receptors. MMGBSA calculations were in accordance with the receptor in vitro binding affinity studies, which indicated that SERAAK2 is a potent ligand of 5-HT1A and 5-HT2A receptors. It was also found that SERAAK2 displays favorable ADMET parameters. The demonstrated anxiolytic- and antidepressant-like effects of SERAAK2 in animal models, which may involve its interaction with 5-HT1A receptors, warrant further studies to confirm these activities and elucidate the underlying mechanisms.

The Na+ /Ca2+ exchanger plays a key role in the regulation of calcium homeostasis in most excitable cells. Three mammalian isoforms, NCX1, NCX2, and NCX3, are described, and with their splice variant, they are expressed in a tissue-specific manner and regulated by Ca2+ binding domains CBD1 and CBD2. Among the three isoforms, NCX3 is mainly expressed in the brain and skeletal muscle. The occurrence of [Na+]i and [Ca2+]i dyshomeostasis has been reported in several neurodegenerative diseases either at neuronal or glial levels. Although the role of each isoform is still under investigation, many lines of evidence point to a neuroprotective effect of NCX3 activation in several neurodegenerative diseases, including brain ischemia. On this light, we have designed, synthesized, and characterized novel 1,4-benzothiazepinonic derivatives structurally related to CGP37157, which is already described as a mitochondrial NCX (mNCX) blocker with a poor selectivity, where a cyclic amine has been linked in position 1 via an acetyl spacer. The newly synthesized compounds were screened for NCX3 activity by Fluo-4 single-cell microfluorimetry and patch-clamp electrophysiology in BHK cells singly expressing this isoform. Identification of the newly synthesized compounds modulating NCX3 activity was obtained by measuring Na+-free-dependent Ca2+ level changes above basal values and/or by electrophysiological detected NCX3 currents. Among the several newly synthesized pharmacological modulators of NCX3, compound 10 has shown the greatest capability of increasing the NCX3 activity in an in vivo model of focal brain ischemia.

G protein-coupled receptors (GPCRs) represent key drug targets, with approximately 30%-40% of all medications acting on these receptors. Recent advancements have uncovered the complexity of GPCR signaling, including biased signaling, which allows selective activation of specific intracellular pathways-primarily mediated by G proteins and β-arrestins. Among aminergic GPCRs, the serotonin 5-HT2A receptor has garnered attention for its potential to generate therapeutic effects without adverse outcomes, such as hallucinations, through biased agonism. This review delivers a comprehensive overview of 5-HT2A receptor-biased signaling and its significance in developing safer mental health therapeutics, particularly for depression and anxiety. We provide a critical evaluation of methodologies for assessing biased signaling, spanning from traditional radioligand binding assays to advanced biosensor technologies. Furthermore, we review structural studies and computational modeling that have identified key receptor residues modulating biased signaling. We also highlight novel biased ligands with selective pathway activation, presenting a promising avenue for developing targeted antidepressant therapies without psychedelic effects. Additionally, we explore the 5-HT2A receptor's role in memory processes and stress response regulation. Ultimately, advancing our understanding of 5-HT2A receptor-biased signaling could drive the development of next-generation GPCR-targeted therapies, maximizing therapeutic efficacy while minimizing side effects in psychiatric treatment.

Arylpiperazines are considered a “privileged scaffold” in medical chemistry due to their versatility and modular structure, enabling modifications towards diverse molecular targets with desired potency, selectivity, and pharmacokinetic properties. In particular, arylpiperazines are aminergic G protein-coupled receptor (GPCR) ligands and neurotransmitter transporter inhibitors, making this group of compounds attractive in central nervous system (CNS) drug discovery for treating schizophrenia, depression, sleep disorders, and Parkinson’s disease (PD). Furthermore, arylpiperazines may possess anticancer properties and can modulate some molecular targets involved in this disease. This review focuses on the structural aspects of arylpiperazines as aminergic GPCR ligands. The review centers on biologically active arylpiperazines with known X-ray structures, providing a detailed discussion of the conformations in the solid state. Next, their interactions with the aminergic GPCRs, based on experimental and molecular modelling studies, are addressed, making this review a comprehensive resource for medicinal and structural chemists working on arylpiperazines.

Spatially offset Raman spectroscopy (SORS) enhanced the capabilities of Raman spectroscopy for the depth-resolved analysis of biological and diffusely scattering samples. This technique offers selective probing of subsurface layers, providing molecular insights without invasive procedures. While SORS has found application in biomedical research, up to now, studies have focused mainly on the detection of mineralization of bones and tissues. Herein, for the first time, SORS is used to assess the soft, organic tissue beneath the skin's surface. In this study, we demonstrate the diagnostic utility of a hand-held SORS device for evaluating the chemical composition of the adipose tissue. We compared perigonadal white adipose tissue (gWAT) in a murine model of atherosclerosis, heart failure, and high-fat diet (HFD) induced obesity. Our results reveal distinct chemical differences in gWAT between HFD-fed and control mice, showcasing the potential of SORS for intravital adipose tissue phenotype characterization. Furthermore, our findings underscore the effectiveness of SORS as a valuable tool for noninvasive assessment of the adipose tissue composition, holding potential diagnostic significance for metabolic disorders.

Raman optical activity (ROA) has truly reached middle age at 50 years. The technique has matured significantly in this period, both with respect to instrument development and number of applications and users. Yet, ROA is still viewed as an auxiliary technique, compared to conventional Raman and infrared absorption spectroscopies. In this perspective, we outline the newest trends in the field of ROA, including exciting opportunities for future developments and of course ask the important question: what is the future of ROA?

Treatment of schizophrenia with currently available drugs is often ineffective or results in several adverse reactions. In previous studies focusing on the search for new antipsychotic drugs, we designed and obtained a series of dopamine D2 and serotonin 5-HT1A and 5-HT2A receptor ligands that were pharmacologically evaluated and showed promising antipsychotic activity. Evaluation of ADMET parameters is an important issue in drug development and should be performed at its early stage to avoid developing molecules with poor pharmacokinetics, that are unlikely to enter the market. For this reason, in this work we focused on the assessment of physicochemical parameters of selected compounds from the series we obtained to assess their drug-like potential. The results of thermal analysis showed that most of the tested compounds are thermally stable above 200 °C, with one compound stable up to 190 °C. Permeability through biological membranes assessed in the parallel artificial membrane permeability assay indicated that all tested compounds effectively migrate through biological membranes by means of passive diffusion. The solubility of the tested compounds was determined in PBS, reflecting physiological pH, and 0.01 M HCl, indicating their low to moderate solubility in PBS, which was significantly improved in acidic environment. The lipophilicity of the studied compounds expressed as LogD falls within the range of 1.84–2.80, what suggest that they would show good oral absorption and the ability to cross lipid barriers. The studies were supplemented with in silico prediction of ADMET parameters, which also indicate the probable high drug-likeness of the tested compounds.

BACKGROUND & AIMS:Butyric (one of the short-chain fatty acids), a major byproduct of the fermentation of non-digestible carbohydrates (e.g. fiber), is supposed to have anti-obesity and anti-inflammatory properties. However, butyrate's potential and mechanism in preventing obesity and the efficient form of administration remain to be clarified.METHODS:Hence, we studied the effect of oral supplementation with 5% (w/w) sodium butyrate and 4% (w/w) β-glucan (fiber) on young male mice (C57BL/6J) with high-fat diet-induced obesity (HFD: 60 kcal% of fat + 1% of cholesterol). Six weeks old mice were fed diets based on HFD or control (AIN-93G) diet with/without supplements for 4 weeks. The unique, interdisciplinary approach combining several Raman-based techniques (including Raman microscopy and fiber optic Raman spectroscopy) and next-generation sequencing was used to ex vivo analyze various depots of the adipose tissue (white, brown, perivascular) and gut microbiome, respectively.RESULTS:The findings demonstrate that sodium butyrate more effectively prevent the pathological increase in body weight caused by elevated saturated fatty acids influx linked to a HFD in comparison to β-glucan, thereby entirely inhibiting diet-induced obesity. Moreover, butyrate significantly affects the white adipose tissue (WAT) reducing the epididymal WAT mass in comparison to HFD without supplements, and decreasing lipid saturation in the epididymal WAT and perivascular adipose tissue of the thoracic aorta. Contrarily, β-glucan significantly changes the composition and diversity of the gut microbiome, reversing the HFD effect, but shows no effect on the epididymal WAT mass and therefore the weight gain inhibition is not as effective as with sodium butyrate.CONCLUSIONS:Here, oral supplementation with sodium butyrate and β-glucan (fiber) has been proven to have an anti-obesity effect through two different targets. Administration-dependent effects that butyrate imposes on the adipose tissue (oral administration) and microbiome (fiber-derived) make it a promising candidate for the personalized treatment of obesity.

Previously, we demonstrated that palmatine (PALM) – an isoquinoline alkaloid from Berberis sibrica radix, exerted antiseizure activity in the pentylenetetrazole (PTZ)-induced seizure assay in larval zebrafish. The aim of the present study was to more precisely characterize PALM as a potential anticonvulsant drug candidate. A range of zebrafish and mouse seizure/epilepsy models were applied in the investigation. Immunostaining analysis was conducted to assess the changes in mouse brains, while in silico molecular modelling was performed to determine potential targets for PALM. Accordingly, PALM had anticonvulsant effect in ethyl 2-ketopent-4-enoate (EKP)-induced seizure assay in zebrafish larvae as well as in the 6 Hz-induced psychomotor seizure threshold and timed infusion PTZ tests in mice. The protective effect in the EKP-induced seizure assay was confirmed in the local field potential recordings. PALM did not affect seizures in the gabra1a knockout line of zebrafish larvae. In the scn1Lab-/- zebrafish line, pretreatment with PALM potentiated seizure-like behaviour of larvae. Repetitive treatment with PALM, however, did not reduce development of PTZ-induced seizure activity nor prevent the loss of parvalbumin-interneurons in the hippocampus of the PTZ kindled mice. In silico molecular modelling revealed that the noted anticonvulsant effect of PALM in EKP-induced seizure assay might result from its interactions with glutamic acid decarboxylase and/or via AMPA receptor non-competitive antagonism. Our study has demonstrated the anticonvulsant activity of PALM in some experimental models of seizures, including a model of pharmacoresistant seizures induced by EKP. These results indicate that PALM might be a suitable new drug candidate but the precise mechanism of its anticonvulsant activity has to be determined.

Androgens like testosterone and dihydrotestosterone play a key role in prostate cancer progression, making the enzyme CYP17A1, essential for androgen synthesis, a crucial therapeutic target. Recent studies have revealed electron density at the substrate entry channel, suggesting the presence of a secondary binding site. In this study, we calculated the binding free energy landscape of known ligands at this site using Funnel Metadynamics. Our results characterize this binding site and indicate that nonheme-interacting ligands could effectively bind to CYP17A1, providing a novel approach to the design of CYP17A1 inhibitors.

Carotenoids are very effectively delivered by albumin to adipocytes. The uptake of carotenoids to the cells occurs in the form of self-aggregates that localize in the vicinity of the adipocyte membrane, as shown by high spatial resolution Raman spectroscopy. The binding of carotenoids to albumin and the mechanism of their transport were elucidated with the help of chiroptical spectroscopies, in tandem with molecular docking and molecular dynamics simulations. In particular, apart from the recognized high affinity pocket of albumin that binds a carotenoid monomer in domain I, we have identified a hydrophobic periphery area in domain IIIB that loosely bounds the self-aggregated carotenoid in aqueous media and enables its easy detachment in hydrophobic environments. This explains the effectiveness of albumins as nanocarriers of carotenoids to adipocytes in vitro. A hydrophobic periphery area of albumin loosely bounds the self-aggregated astaxanthin in water and enables its easy detachment in hydrophobic environment. This explains the effectiveness of albumins as nanocarriers of carotenoids to adipocytes.