Small Macrocycles As Highly Active Integrin α2β1 Antagonists

Starting from clinical candidates Firategrast, Valategrast, and AJM-300, a series of novel macrocyclic platelet collagen receptor α2β1 antagonists were developed. The amino acid derived low molecular weight 14–18-membered macrocycles turned out to be highly active toward integrin α2β1 with IC₅₀s in the low nanomolar range. The conformation of the macrocycles was found to be highly important for the activity, and an X-ray crystal structure was obtained to clarify this. Subsequent docking into the metal-ion-dependent adhesion site (MIDAS) of a β1 unit revealed a binding model indicating key binding features. Macrocycle <b>38</b> was selected for further in vitro and in vivo profiling

Mass Spectrometric Analysis of Noncovalent Complexes Between Synthetic Peptides from Human Ribosomal Protein L7 and Protein G

<div><p>In order to gain a comprehensive insight into the complexes of human ribosomal protein L7 with protein G in a certain degree, an investigation on the complexes of five synthetic L7 peptides, containing the basic-region-leucine-zipper (BZIP)-like domain (aa 15–49), with protein G was performed using nanoelectrospray ionization mass spectrometry (nanoESI-MS). Circular dichroism (CD) was used to characterize the secondary structures of L7 peptides. The characteristics of the complexes between L7 peptides and protein G were studied under various conditions, such as molar ratio of ligands, solvent condition, declustering potential, and peptide sequence. The stability of the complexes is found to decrease with increased declustering potential (>20 V), decreased pH (<5), increased pH (>5), while L7 peptide sequence had no obvious effect on the complex formation. Taken together, the complexes of L7 peptides with protein G are specific noncovalent binding with 1:1 stoichiometry. Because of the availability of synthetic L7 peptides, they might be used as baits to discover the binding partners of protein L7. Furthermore, the elaboration of the binding mechanisms of L7 peptides with protein G could benefit further application of protein G.</p></div

Sulfamide as Zinc Binding Motif in Small Molecule Inhibitors of Activated Thrombin Activatable Fibrinolysis Inhibitor (TAFIa)

Previously disclosed TAFIa inhibitors having a urea zinc-binding motif were used as the starting point for the development of a novel class of highly potent inhibitors having a sulfamide zinc-binding motif. High-resolution X-ray cocrystal structures were used to optimize the structures and reveal a highly unusual sulfamide configuration. A selected sulfamide was profiled in vitro and in vivo and displayed a promising ADMET profile

Sulfamide as Zinc Binding Motif in Small Molecule Inhibitors of Activated Thrombin Activatable Fibrinolysis Inhibitor (TAFIa)

Previously disclosed TAFIa inhibitors having a urea zinc-binding motif were used as the starting point for the development of a novel class of highly potent inhibitors having a sulfamide zinc-binding motif. High-resolution X-ray cocrystal structures were used to optimize the structures and reveal a highly unusual sulfamide configuration. A selected sulfamide was profiled in vitro and in vivo and displayed a promising ADMET profile

Sulfamide as Zinc Binding Motif in Small Molecule Inhibitors of Activated Thrombin Activatable Fibrinolysis Inhibitor (TAFIa)

Previously disclosed TAFIa inhibitors having a urea zinc-binding motif were used as the starting point for the development of a novel class of highly potent inhibitors having a sulfamide zinc-binding motif. High-resolution X-ray cocrystal structures were used to optimize the structures and reveal a highly unusual sulfamide configuration. A selected sulfamide was profiled in vitro and in vivo and displayed a promising ADMET profile

Novel Small Molecule Inhibitors of Activated Thrombin Activatable Fibrinolysis Inhibitor (TAFIa) from Natural Product Anabaenopeptin

Anabaenopeptins isolated from cyanobacteria were identified as inhibitors of carboxypeptidase TAFIa. Cocrystal structures of these macrocyclic natural product inhibitors in a modified porcine carboxypeptidase B revealed their binding mode and provided the basis for the rational design of small molecule inhibitors with a previously unknown central urea motif. Optimization based on these design concepts allowed for a rapid evaluation of the SAR and delivered potent small molecule inhibitors of TAFIa with a promising overall profile

Identification of High-Affinity P2Y₁₂ Antagonists Based on a Phenylpyrazole Glutamic Acid Piperazine Backbone

A series of novel, highly potent P2Y₁₂ antagonists as inhibitors of platelet aggregation based on a phenylpyrazole glutamic acid piperazine backbone is described. Exploration of the structural requirements of the substituents by probing the structure–activity relationship along this backbone led to the discovery of the <i>N</i>-acetyl-(<i>S</i>)-proline cyclobutyl amide moiety as a highly privileged motif. Combining the most favorable substituents led to remarkably potent P2Y₁₂ antagonists displaying not only low nanomolar binding affinity to the P2Y₁₂ receptor but also a low nanomolar inhibition of platelet aggregation in the human platelet rich plasma assay with IC₅₀ values below 50 nM. Using a homology and a three-dimensional quantitative structure–activity relationship model, a binding hypothesis elucidating the impact of several structural features was developed

Novel β‑Amino Acid Derivatives as Inhibitors of Cathepsin A

Cathepsin A (CatA) is a serine carboxypeptidase distributed between lysosomes, cell membrane, and extracellular space. Several peptide hormones including bradykinin and angiotensin I have been described as substrates. Therefore, the inhibition of CatA has the potential for beneficial effects in cardiovascular diseases. Pharmacological inhibition of CatA by the natural product ebelactone B increased renal bradykinin levels and prevented the development of salt-induced hypertension. However, so far no small molecule inhibitors of CatA with oral bioavailability have been described to allow further pharmacological profiling. In our work we identified novel β-amino acid derivatives as inhibitors of CatA after a HTS analysis based on a project adapted fragment approach. The new inhibitors showed beneficial ADME and pharmacokinetic profiles, and their binding modes were established by X-ray crystallography. Further investigations led to the identification of a hitherto unknown pathophysiological role of CatA in cardiac hypertrophy. One of our inhibitors is currently undergoing phase I clinical trials

Image5_An orally available small molecule that targets soluble TNF to deliver anti-TNF biologic-like efficacy in rheumatoid arthritis.tif

Tumor necrosis factor (TNF) is a pleiotropic cytokine belonging to a family of trimeric proteins with both proinflammatory and immunoregulatory functions. TNF is a key mediator in autoimmune diseases and during the last couple of decades several biologic drugs have delivered new therapeutic options for patients suffering from chronic autoimmune diseases such as rheumatoid arthritis and chronic inflammatory bowel disease. Attempts to design small molecule therapies directed to this cytokine have not led to approved products yet. Here we report the discovery and development of a potent small molecule inhibitor of TNF that was recently moved into phase 1 clinical trials. The molecule, SAR441566, stabilizes an asymmetrical form of the soluble TNF trimer, compromises downstream signaling and inhibits the functions of TNF in vitro and in vivo. With SAR441566 being studied in healthy volunteers we hope to deliver a more convenient orally bioavailable and effective treatment option for patients suffering with chronic autoimmune diseases compared to established biologic drugs targeting TNF.</p

Image4_An orally available small molecule that targets soluble TNF to deliver anti-TNF biologic-like efficacy in rheumatoid arthritis.tif

Tumor necrosis factor (TNF) is a pleiotropic cytokine belonging to a family of trimeric proteins with both proinflammatory and immunoregulatory functions. TNF is a key mediator in autoimmune diseases and during the last couple of decades several biologic drugs have delivered new therapeutic options for patients suffering from chronic autoimmune diseases such as rheumatoid arthritis and chronic inflammatory bowel disease. Attempts to design small molecule therapies directed to this cytokine have not led to approved products yet. Here we report the discovery and development of a potent small molecule inhibitor of TNF that was recently moved into phase 1 clinical trials. The molecule, SAR441566, stabilizes an asymmetrical form of the soluble TNF trimer, compromises downstream signaling and inhibits the functions of TNF in vitro and in vivo. With SAR441566 being studied in healthy volunteers we hope to deliver a more convenient orally bioavailable and effective treatment option for patients suffering with chronic autoimmune diseases compared to established biologic drugs targeting TNF.</p