The effect of small-molecule inhibition of MAPKAPK2 on cell ageing phenotypes of fibroblasts from human Werner syndrome

Simple and efficient one-pot multi-step strategy for the synthesis of 2-substituted (1,2,5-triarylpyrrolo[3,2-c]pyridin-3-yl)-N-arylacetamide derivatives in water

A novel one-pot multi-step domino strategy for the synthesis of functionalized 2-substituted acetic acids, 2-substituted (1,2,5-triarylpyrrolo[3,2-c]pyridin-3-yl)acetates and 2-substituted-(1,2,5-triarylpyrrolo[3,2-c]pyridin-3-yl)-N-arylacetamides has been established from inexpensive and readily available starting materials. The reaction can be easily performed by employing different substrates via a one-pot multi-step domino reaction. The target products can be easily obtained with satisfactory yields by only simple recrystallization from a mixture of hot 95% ethanol and N,N-dimethylformamide. The reaction features of readily available starting materials, broad substrate scope, bond-forming efficiency, simple one-pot multi-step synthesis as well as green reaction media, make the procedure highly useful for the construction of potential pharmacological heterocyclic molecules.

Targeting Mitogen-Activated Protein Kinase-Activated Protein Kinase 2 (MAPKAPK2, MK2): Medicinal Chemistry Efforts To Lead Small Molecule Inhibitors to Clinical Trials

The p38/MAPK-activated kinase 2 (MK2) pathway is involved in a series of pathological conditions (inflammation diseases and metastasis) and in the resistance mechanism to antitumor agents. None of the p38 inhibitors entered advanced clinical trials because of their unwanted systemic side effects. For this reason, MK2 was identified as an alternative target to block the pathway but avoiding the side effects of p38 inhibition. However, ATP-competitive MK2 inhibitors suffered from low solubility, poor cell permeability, and scarce kinase selectivity. Fortunately, non-ATP-competitive inhibitors of MK2 have been already discovered that allowed circumventing the selectivity issue. These compounds showed the additional advantage to be effective at lower concentrations in comparison to the ATP-competitive inhibitors. Therefore, although the significant difficulties encountered during the development of these inhibitors, MK2 is still considered as an attractive target to treat inflammation and related diseases to prevent tumor metastasis and to increase tumor sensitivity to chemotherapeutics.

Suppression of the senescence-associated secretory phenotype (SASP) in human fibroblasts using small molecule inhibitors of p38 MAP kinase and MK2

Senescent cells show an altered secretome profile termed the senescence-associated secretory phenotype (SASP). There is an increasing body of evidence that suggests that the accumulation of SASP-positive senescent cells in humans is partially causal in the observed shift to a low-level pro-inflammatory state in aged individuals. This in turn suggests the SASP as a possible therapeutic target to ameliorate inflammatory conditions in the elderly, and thus a better understanding of the signalling pathways underlying the SASP are required. Prior studies using the early generation p38 MAPK inhibitor SB203580 indicated that p38 signalling was required for the SASP. In this study, we extend these observations using two next-generation p38 inhibitors (UR-13756 and BIRB 796) that have markedly improved selectivity and specificity compared to SB203580, to strengthen the evidence that the SASP is p38-dependent in human fibroblasts. BIRB 796 has an efficacy and toxicity profile that has allowed it to reach Phase III clinical trials, suggesting its possible use to suppress the SASP in vivo. We also demonstrate for the first time a requirement for signalling through the p38 downstream MK2 kinase in the regulation of the SASP using two MK2 inhibitors. Finally, we demonstrate that a commercially-available multiplex cytokine assay technology can be used to detect SASP components in the conditioned medium of cultured fibroblasts from both young and elderly donors. This assay is a high-throughput, multiplex microtitre-based assay system that is highly sensitive, with very low sample requirements, allowing it to be used for low-volume human biological fluids. Our initial studies using existing multiplex plates form the basis for a “SASP signature” assay that could be used as a high-throughput system in a clinical study setting. Our findings therefore provide important steps towards the study of, and intervention in, the SASP in human ageing and age-related disease.

Microwave-Assisted Synthesis of a MK2 Inhibitor by Suzuki-Miyaura Coupling for Study in Werner Syndrome Cells

Microwave-assisted Suzuki-Miyaura cross-coupling reactions have been employed towards the synthesis of three different MAPKAPK2 (MK2) inhibitors to study accelerated aging in Werner syndrome (WS) cells, including the cross-coupling of a 2-chloroquinoline with a 3-pyridinylboronic acid, the coupling of an aryl bromide with an indolylboronic acid and the reaction of a 3-amino-4-bromopyrazole with 4-carbamoylphenylboronic acid. In all of these processes, the Suzuki-Miyaura reaction was fast and relatively efficient using a palladium catalyst under microwave irradiation. The process was incorporated into a rapid 3-step microwave-assisted method for the synthesis of a MK2 inhibitor involving 3-aminopyrazole formation, pyrazole C-4 bromination using N-bromosuccinimide (NBS), and Suzuki-Miyaura cross-coupling of the pyrazolyl bromide with 4-carbamoylphenylboronic acid to give the target 4-arylpyrazole in 35% overall yield, suitable for study in WS cells.

Microwave-assisted synthesis of 3-aminobenzo[b]thiophene scaffolds for the preparation of kinase inhibitors

Microwave-assisted synthesis of 3-aminobenzo[b]thiophenes has been applied to 3 kinase inhibitor scaffolds.

Nijmegen breakage syndrome fibroblasts expressing the C-terminal truncated NBN(p70) protein undergo p38/MK2-dependent premature senescence

Fibroblasts from the progeroid Nijmegen breakage syndrome that express a truncated version of the nibrin protein (NBN^p70) undergo premature senescence and have an enlarged morphology with high levels of senescence-associated β-galactosidase, although they do not have F-actin stress fibres. Growth of these fibroblasts in the continuous presence of p38 inhibitors resulted in a large increase in replicative capacity and changed the cellular morphology so that the cells resembled young normal fibroblasts. A similar effect was seen using an inhibitor of the p38 downstream effector kinase MK2. These data suggest that NBN^p70 expressing cells undergo a degree of stress-induced replicative senescence via p38/MK2 activation, potentially due to increased telomere dysfunction, that may play a role in the progeroid features seen in this syndrome.

Entada africana fraction CH₂Cl₂/MEOH 5% inhibits inducible nitric oxide synthase and pro-inflammatory cytokines gene expression induced by lipopolysaccharide in microglia

Background

Inflammatory response in the CNS mediated by microglia cells play an important role in host defense and is implicated in the pathology of neurodegenerative diseases. We investigated the capacity of Entada africana to protect microglia from inflammatory insults by exploring the effect of the CH₂Cl₂/MEOH 5% fraction (Ea5) on pro-inflammatory cytokines mRNA expression. Finally, we studied the effect of Ea5 on the inhibition of p38 MAPK Kinase. The results were compared to those obtained with Baicalin, a well reported anti-inflammatory flavonoid.

Methods

Barks from E. africana were harvested in 2010, in the west region of Cameroon. A crude extract was prepared using CH₂Cl₂/MEOH 1:1 V/V. The crude extract obtained was further fractionated by flash chromatography. A mouse microglia cell line (N9) was stimulated by LPS with or without different concentrations of Baicalin and Ea5. The release of NO was evaluated using the Griess method. The expression of pro-inflammatory cytokines mRNA (TNFα, IL-1β, IL-6) and iNOS/NO were measured by RT- PCR. The inhibition of p38 MAPK Kinase was assessed using ELISA.

Results

We found that Ea5, as well as Baicalin inhibited LPS-induced NO production in a dose dependent manner. Ea5 was most active in term of NO inhibition (87.07%), in comparison to Baicalin (70.85%). The expression of TNFα, IL-1β, IL-6 and iNOS was strongly suppressed by Ea5 in microglia. Ea5 also inhibited the activity of p38MAPK Kinase, up to 30% for the concentrations tested, whereas a prominent inhibition was obtained with Baicalin.

Conclusion

These results suggest that E. africana may contain promising compounds useful for the treatment of diseases cause by over-activation of microglia such as Alzheimer disease and other neurological diseases.