Design Of Drug-Like Protein-Protein Interaction Stabilizers Guided By Chelation-Controlled Bioactive Conformation Stabilization

International audienceThe protein-protein interactions (PPIs) of 14-3-3 proteins are a model system for studying PPI stabilization. The complex natural product Fusicoccin A stabilizes many 14-3-3 PPIs but is not amenable for use in SAR studies, motivating the search for more drug-like chemical matter. However, drug-like 14-3-3 PPI stabilizers enabling such study have remained elusive. An X-ray crystal structure of a PPI in complex with an extremely low potency stabilizer uncovered an unexpected non-protein interacting, ligand-chelated Mg 2+ leading to the discovery of metal ion-dependent 14-3-3 PPI stabilization potency. This originates from a novel chelation-controlled bioactive conformation stabilization effect. Metal chelation has been associated with pan-assay interference compounds (PAINS) and frequent hitter behavior, but chelation can evidently also lead to true potency gains and find use as a medicinal chemistry strategy to guide compound optimization. To demonstrate this, we exploited the effect to design the first potent, selective and drug-like 14-3-3 PPI stabilizers

Phosphorylated full-length Tau interacts with 14-3-3 proteins via two short phosphorylated sequences, each occupying a binding groove of 14-3-3 dimer

International audienceProtein-protein interactions (PPIs) remain poorly explored targets for the treatment of Alzheimer’s disease (AD). The interaction of 14-3-3 proteins with Tau was shown to have detrimental effects on neuronal cells and to be linked to Tau pathology. This PPI is therefore seen as a potential target for AD. When Tau is phosphorylated by PKA (Tau-PKA), two 14-3-3 binding epitopes are generated, surrounding the phosphorylated serines 214 and 324 of Tau. The crystal structures of 14-3-3 in complex with peptides surrounding these Tau phosphosites show that both these motifs are anchored in the amphipathic binding groove of 14-3-3. However, in the absence of structural data with the full-length Tau protein, the stoichiometry of the complex or the interface and affinity of the partners, are still unclear. In this work, we addressed these points, using a broad range of biophysical techniques. The interaction of the long disordered Tau-PKA protein with 14-3-3σ is restricted to two short sequences, containing phosphorylated serines, which bind in the amphipathic binding groove of 14-3-3. Phosphorylation of Tau is fundamental for the formation of this stable complex, and the affinity of the Tau-PKA/14-3-3 interaction is in the 1-10 micromolar range. Each monomer of the 14-3-3σ dimer binds one of the two different phosphorylated peptides of Tau-PKA, suggesting a 14-3-3/Tau-PKA stoichiometry of 2:1, confirmed by analytical ultracentrifugation. These results contribute to a better understanding of this PPI and provide useful insights for drug discovery projects aiming at the inhibition of this interaction

Prevalence of Sarcopenia in Older Patients in Rehabilitation Wards

The multidisciplinary assessment of hospitalized patients via validated scales and tools has become crucial in the early identification of sarcopenia. The objective of this study was to determine the prevalence of sarcopenia and its related factors in patients aged ≥65 years admitted to the neurological rehabilitation departments of cognitive motor disorders and functional motor rehabilitation at the IRCCS Hospital San Raffaele in Milan. Using the algorithm reported by the European Working Group on Sarcopenia in Older People (EWGSOP2), the prevalence of sarcopenia in patients was investigated from 2019–2020. Definite sarcopenia was detected in 161 of 336 recruited patients (47.9%). Age was significantly higher in sarcopenic patients than in those without sarcopenia (median 81 vs. 79 years, p p p p p < 0.005 for both). In conclusion, sarcopenic patients were more cognitively impaired and less autonomous in their daily life, but the majority presented with a negative malnutrition screening test

Co-Infection of L. monocytogenes and Toxoplasma gondii in a Sheep Flock Causing Abortion and Lamb Deaths

Abortion in livestock is a public health burden, and the cause of economic losses for farmers. Abortion can be multifactorial, and a deep diagnostic investigation is important to reduce the spread of zoonotic disease and public health prevention. In our study, a multidisciplinary investigation was conducted to address the cause of increased abortion and lamb mortality on a farm, which detected a co-infection of Listeria monocytogenes and Toxoplasma gondii. Hence, it was possible to conclude that this was the reason for a reduced flock health status and the cause of an increased abortion rate. Furthermore, the investigation work and identification of the L. monocytogenes infection root allowed the reduction of economic loss

CCDC 2190057: Experimental Crystal Structure Determination

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures

Designing Selective Drug-like Molecular Glues for the Glucocorticoid Receptor/14-3‑3 Protein–Protein Interaction

The ubiquitously expressed glucocorticoid receptor (GR) is a nuclear receptor that controls a broad range of biological processes and is activated by steroidal glucocorticoids such as hydrocortisone or dexamethasone. Glucocorticoids are used to treat a wide variety of conditions, from inflammation to cancer but suffer from a range of side effects that motivate the search for safer GR modulators. GR is also regulated outside the steroid-binding site through protein–protein interactions (PPIs) with 14-3-3 adapter proteins. Manipulation of these PPIs will provide insights into noncanonical GR signaling as well as a new level of control over GR activity. We report the first molecular glues that selectively stabilize the 14-3-3/GR PPI using the related nuclear receptor estrogen receptor α (ERα) as a selectivity target to drive design. These 14-3-3/GR PPI stabilizers can be used to dissect noncanonical GR signaling and enable the development of novel atypical GR modulators

Designing Selective Drug-like Molecular Glues for the Glucocorticoid Receptor/14-3‑3 Protein–Protein Interaction

The ubiquitously expressed glucocorticoid receptor (GR) is a nuclear receptor that controls a broad range of biological processes and is activated by steroidal glucocorticoids such as hydrocortisone or dexamethasone. Glucocorticoids are used to treat a wide variety of conditions, from inflammation to cancer but suffer from a range of side effects that motivate the search for safer GR modulators. GR is also regulated outside the steroid-binding site through protein–protein interactions (PPIs) with 14-3-3 adapter proteins. Manipulation of these PPIs will provide insights into noncanonical GR signaling as well as a new level of control over GR activity. We report the first molecular glues that selectively stabilize the 14-3-3/GR PPI using the related nuclear receptor estrogen receptor α (ERα) as a selectivity target to drive design. These 14-3-3/GR PPI stabilizers can be used to dissect noncanonical GR signaling and enable the development of novel atypical GR modulators