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Imidazoline I 2 -IRs) are altered in Alzheimer's disease (AD) patients and are associated with analgesia. I 2 -IRs) are altered in Alzheimer's disease (AD) patients and are associated with analgesia. I 2 -IRs are not structurally described, and their pharmacological characterization relies on their modulation by highly affine ligands. Herein, we describe the synthesis of (3-phenylcarbamoyl-3,4-dihydro-2 H -pyrrol-2-yl)phosphonates endowed with relevant affinities for I 2 -IRs in human brain tissues. The optimal ADME and pharmacokinetic profile of a selected compound, 12d, secured its in vivo exploration in a senescence accelerated prone 8 mice revealing improvement in the cognitive impairment and unveiling the mechanism of action by analyzing specific AD biomarkers. The treatment of a capsaicin-induced mechanical hypersensitivity murine model with 12d revealed analgesic properties devoid of motor coordination issues. The target engagement of 12d was demonstrated by suppression of the analgesic effect by pretreatment with idazoxan. Overall, 12d is a putative candidate for advancing preclinical phases and supports the modulation of I 2 -IRs as an innovative approach for therapeutics.

With the aim of developing novel anti-SARS-CoV-2 drugs to address the ongoing evolution and emergence of drug-resistant strains, the reported SARS-CoV-2 M pro inhibitor WU-04 was selected as a lead to find novel, highly potent, and broad-spectrum inhibitors. Using a fragment-based multilevel virtual screening strategy, 15 hit compounds were identified and subsequently synthesized. Among them, A5 (IC 50 = 1.05 μM), A6 (IC 50 = 1.08 μM), and A9 (IC 50 = 0.154 μM) demonstrated potent SARS-CoV-2 M pro inhibition comparable to or slightly weaker than WU-04 . Antiviral activity evaluations revealed that compound A9 exhibited the strongest antiviral activity with an EC 50 value of 0.18 μM, quite comparable to the marketed drug Nirmatrelvir (EC 50 = 0.123 μM) and inferior to WU-04 (EC 50 = 0.042 μM). Molecular dynamics simulations elucidated the key interactions between compounds A5 , A6 , A9 , and the binding pocket of SARS-CoV-2 M pro , providing valuable insights into their mechanisms of action. These findings identify compound A9 as a promising lead for anti-SARS-CoV-2 drug development.

Inhibition of AP-2-associated protein kinase 1 (AAK1) has been shown to be a promising avenue for the development of broad-spectrum antiviral agents. On a previously described AAK1 inhibitor based on a pyrrolo[2,3-b]pyridine scaffold, the concept of isosterism was applied, by replacing a carboxamide linker by various five-membered heterocycles. It led to the discovery of a novel series of AAK1 inhibitors with IC 50 values in the low nM range, that also displayed antiviral activity against the dengue virus and Venezuelan equine encephalitis virus., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Steven De Jonghe and Shirit Einav reports financial support was provided by US Department of Defense. Steven De Jonghe and Shirit Einav reports financial support was provided by Defense Threat Reduction Agency. Wim Dehaen reports equipment, drugs, or supplies was provided by Hercules Foundation of the Flemish Government. Wim Dehaen reports equipment, drugs, or supplies was provided by FWO-Vlaanderen. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

The synthesis of 1 ' -azido C -nucleosides is described to expand the set of azide-functionalized nucleosides for bioorthogonal applications and as potential antiviral drugs. Lewis acid-promoted azidation of a nucleoside hemiketal resulted in the formation of a tetrazole through a Schmidt reaction manifold. Conformational control to prevent ring-chain tautomerism enabled efficient 1 ' -azidation with complete β-diastereoselectivity. The unique reactivity and further derivation of the 1 ' -azido C -nucleosides are also reported.

Histone deacetylase 6 (HDAC6) is a promising target for treating neurodegenerative disorders, several cancer types and viral infections. Unique among HDACs, the HDAC6 isoform possesses a zinc finger ubiquitin-binding domain (UBD) crucial for managing misfolded protein aggregates and facilitating viral infection. HDAC6 binds aggregated polyubiquitinated proteins through its UBD, mediating their transport to the aggresome and subsequent removal via autophagy. Despite the importance of the UBD in proteostasis and viral infection, its pharmacological inhibition has been minimally explored thus far, with research largely focused on the deacetylase domain. We synthesized a diverse library of new compounds designed to target the HDAC6-UBD, termed HZUBi, with varied core structures including quinazolinone, oxindole and tetrahydrothiopyrano[4,3-b]indole, aimed at enhancing UBD interaction and extending into the side pocket. New structure-activity relationships were established, computational docking and molecular dynamics studies were performed and the functional impact of selected inhibitors was assessed in the context of multiple myeloma and viral infection. Several new HZUBi could displace a ubiquitin peptide from HDAC6-UBD in a differential manner, although to a lower extent than the literature reference compound HZUBi-3e. Despite exhibiting in vitro target engagement, neither HZUBi-3e nor its ester prodrug HZUBi-1e enhanced proteasome inhibitor-mediated multiple myeloma cell killing. Finally, none of the screened HZUBi triggered anti-viral activity., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2025 Elsevier Masson SAS. All rights reserved.)

Thirteen new 4,7-disubstituted pyrimido[4,5- d ]pyrimidines were synthesized via a straightforward methodology starting from thiourea. The anti-proliferative activity of these compounds was evaluated across a diverse panel of eight cancer cell lines, with derivatives 7d and 7h showing efficacy against several hematological cancer types. Furthermore, all compounds were assessed for their antiviral potency against a panel of viruses. Compounds featuring a cyclopropylamino group and an aminoindane moiety exhibited remarkable efficacy against human coronavirus 229E (HCoV-229E). These findings highlight the pyrimidino[4,5- d ]pyrimidine scaffold as an interesting framework for the design of novel antiviral agents against HCoVs, with compounds 7a , 7b , and 7f emerging as strong candidates for further investigation.

Microtubule-targeting agents are an important class of anti-cancer drugs; their full potential is however not realized because of significant myelotoxicity and neurotoxicity. We here report 3-nitropyridine analogues as a novel group of microtubule-targeting agents with potent anti-cancer effects against a broad range of cancer types. We show that these 3-nitropyridines induce cell cycle arrest in the G2-M phase and inhibit tubulin polymerization by interacting with tubulin. Determination of the tubulin-4AZA2996 structure by X-ray crystallography demonstrated that this class of compounds binds to the colchicine-site of tubulin. Furthermore, the anti-cancer effect was demonstrated both in vitro and in vivo in a murine heterotopic xenograft model of colon cancer. When administered intravenously, 4AZA2891 effectively inhibited cancer growth. Whereas 3-nitropyridine compounds do not induce myelotoxicity at pharmacological doses, the neurotoxicity associated with microtubule-targeting agents is still present., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Herman et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Nitrogen-containing steroids are known as prostate cancer therapeutics. In this work, a series of pregnane derivatives bearing an imidazolium moiety were synthesized using Δ 16 -20-ketones as starting material. An improved approach for the construction of the 20-keto-21-heterocycle-substituted fragment involved the rearrangement of 16,17-epoxides with HCl, followed by reaction of the formed α-chloroketone with 1-substituted imidazoles. Binding affinity analysis of the imidazolium steroids and their synthetic intermediates to human CYP17A1 showed only type I (substrate-like) interactions. The strongest affinity was observed for 16α,17α-epoxy-5α-pregnan-20-on-3β-ol (K d  = 0.66 ± 0.05 µM). The steroid derivatives have been evaluated for antitumor activity against a range of prostate cancer cells as well as against various other solid tumor and hematologic cancer cell lines. All 21-imidazolium salts were active against the hormone-dependent prostate cancer line LNCaP. The most pronounced cytotoxicity in solid tumor and hematologic cancer cell lines was observed for intermediate product, 21-chloro-5α-pregn-16-en-20-on-3β-ol. Among the imidazolium salts, the derivatives with a single bond were more cytotoxic than their unsaturated congeners., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Isothiazolo[4,3- b ]pyridines have been extensively explored as inhibitors of cyclin G-associated kinase (GAK). In order to expand the structure-activity relationship study and to discover other chemotypes that act as GAK inhibitors, the closely related isothiazolo[4,5- b ]pyridine scaffold was explored. An easy and efficient synthetic procedure to access 3,5- and 3,6-dihalogenated isothiazolo[4,5- b ]pyridines as key building blocks was developed. Regioselective functionalization with various substituents was performed. None of the newly synthesized isothiazolo[4,5- b ]pyridines were active as GAK inhibitors. Molecular modeling was applied to rationalise their inactivity as GAK binders.

Ad26.COV2.S vaccination can lead to vaccine-induced immune thrombotic thrombocytopenia (VITT), a rare but severe adverse effect, characterized by thrombocytopenia and thrombosis. The mechanism of VITT induction is unclear and likely multifactorial, potentially including the activation of platelets and endothelial cells mediated by the vaccine-encoded spike protein (S protein). Here, we investigated the biodistribution of the S protein after Ad26.COV2.S dosing in three animal models and in human serum samples. The S protein was transiently present in draining lymph nodes of rabbits after Ad26.COV2.S dosing. The S protein was detected in the serum in all species from 1 day to 21 days after vaccination with Ad26.COV2.S, but it was not detected in platelets, the endothelium lining the blood vessels, or other organs. The S protein S1 and S2 subunits were detected at different ratios and magnitudes after Ad26.COV2.S or COVID-19 mRNA vaccine immunization. However, the S1/S2 ratio did not depend on the Ad26 platform, but on mutation of the furin cleavage site, suggesting that the S1/S2 ratio is not VITT related. Overall, our data suggest that the S-protein biodistribution and kinetics after Ad26.COV2.S dosing are likely not main contributors to the development of VITT, but other S-protein-specific parameters require further investigation.

In search for broad-spectrum antivirals, we discovered a small molecule inhibitor, RMC-113, that potently suppresses the replication of multiple RNA viruses including SARS-CoV-2 in human lung organoids. We demonstrated selective dual inhibition of the lipid kinases PIP4K2C and PIKfyve by RMC-113 and target engagement by its clickable analog. Advanced lipidomics revealed alteration of SARS-CoV-2-induced phosphoinositide signature by RMC-113 and linked its antiviral effect with functional PIP4K2C and PIKfyve inhibition. We discovered PIP4K2C's roles in SARS-CoV-2 entry, RNA replication, and assembly/egress, validating it as a druggable antiviral target. Integrating proteomics, single-cell transcriptomics, and functional assays revealed that PIP4K2C binds SARS-CoV-2 nonstructural protein 6 and regulates virus-induced impairment of autophagic flux. Reversing this autophagic flux impairment is a mechanism of antiviral action of RMC-113. These findings reveal virus-induced autophagy regulation via PIP4K2C, an understudied kinase, and propose dual inhibition of PIP4K2C and PIKfyve as a candidate strategy to combat emerging viruses.

The human CC chemokine receptor 8 (CCR8) has been extensively pursued as target for the treatment of various inflammatory disorders. More recently, the importance of CCR8 in the tumor microenvironment has been demonstrated, spurring the interest in CCR8 antagonism as therapeutic strategy in immuno-oncology. On a previously described naphthalene sulfonamide with CCR8 antagonistic properties, the concept of isosterism was applied, leading to the discovery of novel CCR8 antagonists with IC 50 values in the nM range in both the CCL1 competition binding and CCR8 calcium mobilization assay. The excellent CCR8 antagonistic activity of the most potent congeners was rationalized by homology molecular modeling., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Yenthel Verhaegen reports financial support was provided by Fund for Scientific Research. Libao Liu reports financial support was provided by Guangzhou Elite Project. Steven De Jonghe has patent #Novel CCR8 antagonists pending to KU Leuven. Tom Van Loy has patent #Novel CCR8 antagonists pending to KU Leuven. Dominique Schols has patent #Novel CCR8 antagonists pending to KU Leuven. Wim Dehaen has patent #Novel CCR8 antagonists pending to KU Leuven. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

With the aim to identify new antiviral agents with antibacterial properties, a series of 2-quinolone-1,2,3-triazole derivatives bearing α-aminophosphonates was synthesized and characterized by 1 H NMR, 13 C NMR, 31 P NMR, single crystal XRD and HRMS analyses. These compounds were examined against five RNA viruses (YFV, ZIKV, CHIKV, EV71 and HRV) from three distinct families (Picornaviridae, Togaviridae and Flaviviridae) and four bacterial strains (S. aureus, E. feacalis, E. coli and P. aeruginosa). The α-aminophosphonates 4f, 4i, 4j, 4k, 4p and 4q recorded low IC 50 values of 6.8-10.91 μM, along with elevated selectivity indices ranging from 2 to more than 3, particularly against YFV, CHIKV and HRV-B14. Besides, the synthesized compounds were generally more sensitive toward Gram-positive bacteria, with the majority of them displaying significant potency against E. feacalis. Specifically, an excellent anti-enterococcus activity was obtained by compound 4q with MIC and MBC values of 0.03 μmol/mL, which were 8.7 and 10 times greater than those of the reference drugs ampicillin and rifampicin, respectively. Also, compounds 4f, 4p and 4q showed potent anti-staphylococcal activity with MIC values varying between 0.11 and 0.13 μmol/mL, compared to 0.27 μmol/mL for ampicillin. The results from DFT and molecular docking simulations were in agreement with the biological assays, proving the binding capability of hybrids 4f, 4i, 4j, 4k, 4p and 4q with viral and bacterial target enzymes through hydrogen bonds and other non-covalent interactions. The in silico ADME/Tox prediction revealed that these molecules possess moderate to good drug-likeness and pharmacokinetic properties, with a minimal chance of causing liver toxicity or carcinogenic effects., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Masson SAS. All rights reserved.)

Small intestinal epithelial vacuolation induced by a heteroaryldihydropyrimidine compound (HAP-1) was observed in rats but not in dogs at termination in screening toxicity studies, despite the plasma exposure being higher in dogs. To understand the species differences, investigational studies with multiple time points following single dose (SD) and 7-day repeated dose (RD) were conducted in both species at doses resulting in comparable plasma exposures. In rats, epithelial vacuolation in the duodenum and jejunum were observed at all time points. In dogs, transient vacuolation was noted at 8 h post-SD (SD_8h) and 4 h post-RD (RD_4 h), but not at termination (RD_24 h). Special stains demonstrated lipid accumulation within enterocytes in both species and intracytoplasmic inclusion bodies in rats. Transmission electron microscopy identified these inclusion bodies as endoplasmic reticulum (ER) membranous structures. Transcriptomic analysis on jejunal mucosa at SD_8 h and RD_24 h revealed perturbations of lipid metabolism-related genes at SD_8 h in both species, but not at RD_24 h in dogs. ER stress-related gene changes at both time points were observed in rats only. Despite comparable HAP-1 plasma exposures, the duodenum and jejunum tissue concentrations of HAP-1 and acyl glucuronide metabolite were >5- and >30-fold higher in rats than in dogs, respectively. In vitro, similar cytotoxicity was observed in rat and dog duodenal organoids treated with HAP-1. In conclusion, HAP-1-induced intestinal epithelial vacuolation was related to lipid metabolism dysregulation in both species and ER-related injuries in rats only. The species differences were likely related to the difference in intestinal exposure to HAP-1 and its reactive metabolite., (© 2023 John Wiley & Sons Ltd.)

Disubstituted isothiazolo[4,3- b ]pyridines are known inhibitors of cyclin G-associated kinase. Since 3-substituted-7-aryl-isothiazolo[4,3- b ]pyridines remain elusive, a strategy was established to prepare this chemotype, starting from 2,4-dichloro-3-nitropyridine. Selective C-4 arylation using ligand-free Suzuki-Miyaura coupling and palladium-catalyzed aminocarbonylation functioned as key steps in the synthesis. The 3- N -morpholinyl-7-(3,4-dimethoxyphenyl)-isothiazolo[4,3- b ]pyridine was completely devoid of GAK affinity, in contrast to its 3,5- and 3,6-disubstituted congeners. Molecular modeling was applied to rationalize its inactivity as a GAK ligand.

The human CC chemokine receptor 8 (CCR8) is specifically expressed on tumor-infiltrating regulatory T cells (TITRs) and is a promising drug target for cancer immunotherapy. However, the role of CCR8 signaling in TITR biology and the effectiveness of CCR8 small molecule antagonists as TITR-targeting immunotherapy remain subjects of ongoing debate. In this work, we generated a novel cellular model of TITRs by culturing peripheral blood mononuclear cell-derived regulatory T cells in medium containing tumor cell-conditioned medium, CD3/CD28 activator, interleukin-2 and 1α,25-dihydroxyvitamin D3. This cellular model (named TITR mimics) highly and stably expressed a series of TITR signature molecules, including CCR8, FOXP3, CD30, CD39, CD134, CD137, TIGIT and Tim-3. Moreover, TITR mimics displayed robust in vitro immunosuppressive activity. To unravel the functional role of CCR8 in TITR mimics, a chemotaxis assay was performed showing strong and CCR8-specific migration toward CCL1, the natural chemokine agonist of CCR8. However, either stimulation (with CCL1) or blocking (with the small molecule antagonist NS-15) of CCR8 signaling did not affect the immunosuppressive activity, proliferation and survival of TITR mimics. Collectively, our work provides a method for the generation of TITR mimics in vitro, which can be used to study TITR biology and to evaluate drug candidates targeting TITRs. Furthermore, our findings suggest that CCR8 signaling primarily regulates migration of these cells., (© 2024. The Author(s).)

Sixteen new 2-substituted quinazolines were synthesized using a straightforward methodology starting from 2-methoxybezoic acid or 3-methoxy-2-naphthoic acid. The anti-proliferative activity of the target compounds was evaluated against nine cancer cell lines. Additionally, all the compounds were screened for their potency and selectivity against a panel of 109 kinases and four bromodomains, using Differential Scanning Fluorimetry (DSF). Compound 17 bearing a 2-methoxyphenyl substitution along with a basic side chain displayed a remarkable profile against the majority of the tested cell lines.