Patricia Melnyk

The angiotensin II type 1 (AT₁) receptor is a key component of the renin–angiotensin system (RAS) and a validated target for cardiovascular and renal disorders. Developing small molecules with defined AT₁ versus AT₂ binding profiles remains important for both therapeutic and mechanistic studies. Here, a series of novel imidazole-based compounds was synthesized and evaluated for their binding affinities toward angiotensin II type 1 (AT₁) and type 2 (AT₂) receptors. Binding studies were conducted by measuring the displacement of radiolabeled [³H]-angiotensin II ([³H]-AII) in PLC-PRF-5 human hepatoma cells for AT₁ receptors and calf cerebellum membranes for AT₂ receptors. Structure–activity relationship (SAR) analysis revealed that sulfonamide substitution significantly enhanced AT₁ receptor affinity, whereas sterically hindered derivatives and ester-containing compounds were less active. Molecular docking studies using the AT₁ receptor crystal structure (PDB: 8TH4) rationalized the observed activity trends. The most active compound showed high AT₁ affinity (Ki = 5 nM), comparable to losartan, and all compounds displayed preferential binding for AT₁ over AT₂ receptors.

Central nervous system (CNS) disorders such as neurodegenerative diseases, multiple sclerosis, or even brain ischemia represent major therapeutic challenges with limited effective treatments. The sigma-1 receptor (S1R), a unique ligand-operated molecular chaperone enriched at mitochondria-associated membranes, has emerged as a promising drug target due to its role in neuroprotection and neuroinflammation. Building upon our previously identified S1R ligand (compound 1), we designed and synthesized six novel benzamide derivatives through pharmacomodulation to optimize affinity, selectivity, and safety profiles. Among these, compound 2 demonstrated superior S1R affinity, improved selectivity over the sigma-2 receptor (S2R), and favorable ADME properties, including enhanced permeability and markedly reduced in vitro cardiac toxicity compared to the lead compound. Functional assays confirmed the agonist activity of key derivatives, while safety evaluations revealed low cytotoxicity and minimal off-target receptor interactions. Collectively, these findings support compound 2 as a promising candidate for further preclinical development in S1R-related CNS disorders.

Acyl‐coenzyme A synthetase long‐chain family member 4 (ACSL4), a pivotal enzyme in lipid metabolism, has emerged as a therapeutic target for ferroptosis‐related conditions and cancer. However, its reference inhibitor, rosiglitazone, has off‐target activity on peroxisome proliferator‐activated receptor gamma (PPARγ), a key regulator of lipid homeostasis. Here, the discovery of LIBX‐A401, a potent ACSL4 inhibitor derived from rosiglitazone devoid of PPARγ activity, is reported. Its binding to ACSL4 is ATP‐dependent, stabilizing the C‐terminal domain and altering the fatty acid gate region, as shown by Hydrogen‐Deuterium Exchange Mass Spectrometry. Photoaffinity labeling identified A329 within the fatty acid binding site, while molecular dynamics and mutagenesis highlighted Q302 as critical for LIBX‐A401 binding. LIBX‐A401 exhibits anti‐ferroptotic properties in cells, supported by target engagement. These findings establish LIBX‐A401 as a valuable tool to study ACSL4 in ferroptosis and cancer, while its elucidated binding mode paves the way for the rational design of improved inhibitors.

Acyl‐coenzyme A synthetase long‐chain family member 4 (ACSL4), a pivotal enzyme in lipid metabolism, has emerged as a therapeutic target for ferroptosis‐related conditions and cancer. However, its reference inhibitor, rosiglitazone, has off‐target activity on peroxisome proliferator‐activated receptor gamma (PPARγ), a key regulator of lipid homeostasis. Here, the discovery of LIBX‐A401, a potent ACSL4 inhibitor derived from rosiglitazone devoid of PPARγ activity, is reported. Its binding to ACSL4 is ATP‐dependent, stabilizing the C‐terminal domain and altering the fatty acid gate region, as shown by Hydrogen‐Deuterium Exchange Mass Spectrometry. Photoaffinity labeling identified A329 within the fatty acid binding site, while molecular dynamics and mutagenesis highlighted Q302 as critical for LIBX‐A401 binding. LIBX‐A401 exhibits anti‐ferroptotic properties in cells, supported by target engagement. These findings establish LIBX‐A401 as a valuable tool to study ACSL4 in ferroptosis and cancer, while its elucidated binding mode paves the way for the rational design of improved inhibitors.

The adenosine A_2A receptor (A_2AR) has been identified as a therapeutic target for treating neurodegenerative diseases and cancer. In recent years, we have highlighted the 2-aminoquinazoline heterocycle as an promising scaffold for designing new A_2AR antagonists, exemplified by 6-bromo-4-(furan-2-yl)quinazolin-2-amine 1 (K_i (hA_2AR) = 20 nM). Here, we report the synthesis of new 2-aminoquinazoline derivatives with substitutions at the C6- and C7-positions, and the introduction of aminoalkyl chains containing tertiary amines at the C2-position to enhance antagonist activity and solubility properties. Compound 5m showed a high affinity for hA_2AR with a K_i value of 5 nM and demonstrated antagonist activity with an IC₅₀ of 6 µM in a cyclic AMP assay. Introducing aminopentylpiperidine and 4-[(piperidin-1-yl)methyl]aniline substituents maintained the binding affinities (9x, K_i = 21 nM; 10d, K_i = 15 nM) and functional antagonist activities (9x, IC₅₀ = 9 µM; 10d, IC₅₀ = 5 µM) of the synthesized compounds while improving solubility. This study provides insights into the future development of A_2AR antagonists for therapeutic applications.

Lipid metabolism affects many cellular processes essential for homeostasis, and its disruption is linked to various diseases. A key enzyme in these processes, acyl-coenzyme A synthetase long-chain family member 4 (ACSL4), is a promising target for treating conditions involving ferroptosis and certain cancers. Rosiglitazone (ROSI) is a known ACSL4 inhibitor but its potent activity on peroxisome proliferator-activated receptor gamma (PPARγ), a nuclear receptor strongly involved in lipid metabolism constitutes an important limitation. This study focuses on developing novel ACSL4 inhibitors derived from ROSI, which lack PPARγ activity. Binding of the most potent compound of this series (9) relies on the prior binding of ATP. Hydrogen-Deuterium Exchange Mass Spectrometry (HDx-MS) demonstrated that ATP binding stabilizes the ACSL4 C-terminus, an effect enhanced by compound 9, which also alters important peptide sequences, including the fatty acid gate-domain. Photoaffinity Labeling (PAL) with a diazirine-based probe identified residue A329 in the fatty acid pocket. Molecular dynamics simulations and site-directed mutagenesis highlighted Q302 as critical for compound 9 binding. Thus, compound 9 (LIBX-A401) is a promising tool for studying ACSL4 in ferroptosis-related diseases and cancer, and the elucidation of its binding mode paves the way to the rational design of optimized inhibitors

The progress in Alzheimer’s disease (AD) treatment suggests a combined therapeutic approach targeting the two lesional processes of AD, which include amyloid plaques made of toxic Aβ species and neurofibrillary tangles formed of aggregates of abnormally modified Tau proteins. A pharmacophoric design, novel drug synthesis, and structure-activity relationship enabled the selection of a polyamino biaryl PEL24-199 compound. The pharmacologic activity consists of a non-competitive β-secretase (BACE1) modulatory activity in cells. Curative treatment of the Thy-Tau22 model of Tau pathology restores short-term spatial memory, decreases neurofibrillary degeneration, and alleviates astrogliosis and neuroinflammatory reactions. Modulatory effects of PEL24-199 towards APP catalytic byproducts are described in vitro, but whether PEL24-199 can alleviate the Aβ plaque load and associated inflammatory counterparts in vivo remains to be elucidated. We investigated short- and long-term spatial memory, Aβ plaque load, and inflammatory processes in APP^Swe/PSEN1^ΔE9 PEL24-199 treated transgenic model of amyloid pathology to achieve this objective. PEL24-199 curative treatment induced the recovery of spatial memory and decreased the amyloid plaque load in association with decreased astrogliosis and neuroinflammation. The present results underline the synthesis and selection of a promising polyaminobiaryl-based drug that modulates both Tau and, in this case, APP pathology in vivo via a neuroinflammatory-dependent process.

The Hippo pathway consists of a cascade of kinases that controls the phosphorylation of the co-activators YAP/TAZ. When unphosphorylated, YAP and TAZ translocate into the nucleus, where they mainly bind to the TEAD transcription factor family and activate genes related to cell proliferation and survival. In this way, the inhibition of the Hippo pathway promotes cell survival, proliferation, and stemness fate. Another pathway can modulate these processes, namely the Wnt/β-catenin pathway that is indeed involved in cellular functions such as proliferation and cell survival, as well as apoptosis, growth, and cell renewal. Wnt signaling can act in a canonical or noncanonical way, depending on whether β-catenin is involved in the process. In this review, we will focus only on the canonical Wnt pathway. It has emerged that YAP/TAZ are components of the β-catenin destruction complex and that there is a close relationship between the Hippo pathway and the canonical Wnt pathway. Furthermore, recent data have shown that both of these pathways may play a role in neurodegenerative diseases, such as Huntington’s disease, Alzheimer’s disease, or Amyotrophic Lateral Sclerosis. Thus, this review analyzes the Hippo pathway and the Wnt pathway, their crosstalk, and their involvement in Huntington’s disease, as well as in other neurodegenerative disorders. Altogether, these data suggest possible therapeutic approaches targeting key players of these pathways.

The rationale to define the biological and molecular parameters derived from structure–activity relationships (SAR) is mandatory for the lead selection of small drug compounds. Several series of small molecules have been synthesized based on a computer-assisted pharmacophore design derived from two series of compounds whose scaffold originates from chloroquine or amodiaquine. All compounds share similar biological activities. In vivo, Alzheimer’s disease-related pathological lesions are reduced, consisting of amyloid deposition and neurofibrillary degeneration, which restore and reduce cognitive-associated impairments and neuroinflammation, respectively. Screening election was performed using a cell-based assay to measure the repression of Aβ_1–x peptide production, the increased stability of APP metabolites, and modulation of the ratio of autophagy markers. These screening parameters enabled us to select compounds as potent non-competitive β-secretase modulators, associated with various levels of lysosomotropic or autophagy modulatory activities. Structure–activity relationship analyses enabled us to define that (1) selectively reducing the production of Aβ_1–x, and (2) little Aβ_x–40/42 modification together with (3) a decreased ratio of p62/(LC3-I/LC3-II) enabled the selection of non-competitive β-secretase modulators. Increased stability of CTFα and AICD precluded the selection of compounds with lysosomotropic activity whereas cell toxicity was associated with the sole p62 enhanced expression shown to be driven by the loss of nitrogen moieties. These SAR parameters are herein proposed with thresholds that enable the selection of potent anti-Alzheimer drugs for which further investigation is necessary to determine the basic mechanism underlying their mode of action.