Design, Synthesis, and Biological Activity of Novel, Potent, and Selective (Benzoylaminomethyl)thiophene Sulfonamide Inhibitors of c-Jun-N-Terminal Kinase

Design and synthesis of 2′-anilino-4,4′-bipyridines as selective inhibitors of c-Jun N-terminal kinase-3

The design and synthesis of a new series of c-Jun N-terminal kinase-3 (JNK3) inhibitors with selectivity against JNK1 are reported. The novel series of substituted 2'-anilino-4,4'-bipyridines were designed based on a combination of hits from high throughput screening and X-ray crystal structure information of compounds crystallized into the JNK3 ATP binding active site.

Janus kinase-2 signaling mediates apoptosis in rat cardiomyocytes

We tested the hypothesis that activation Jak2, which is prominently involved in the up-regulation of the renin-angiotensin system (RAS), constitutes a focal point in relaying signals triggered by a Angiotensin II (Ang II) and hypoxia/reoxygenation separately to cause an enhanced susceptibility of cardiac myocyte to apoptotic cell death. Ang II-treated adult cardiomyocytes in culture exhibited an increased level of apoptosis that accompanied activation of pro-apoptotic as well as anti-apoptotic signaling pathways. We observed increased phosphorylation of Jak2 kinase, Stat1, JNK, with increased expression of Bax protein, followed by an increase in caspase-1 and caspase-3 activity. Activation of these pro-apoptotic pathways was blocked by the Jak2 pharmacological inhibitor, Tyrphostin AG490. We also observed an increase in phosphorylation of cardioprotective pathway components, namely S6 ribosomal protein, and heat shock protein 27 (HSP27). Likewise, the oxidative stress, via the hypoxia/reoxygenation treatment of rat adult cardiomyocytes, produced apoptosis that was dependent upon activation of Jak2. The apoptotic response was not only reduced by Losartan, an inverse agonist of the AT1, receptor, but by treatment with AG490 as well. Taken together, these observations provide clear evidence in favor of Jak2 signaling as mediator of the apoptotic response in cardiomyocytes. However, there was a concomitant induction of cytoprotective signaling that presumably provides a negative feed-back to the deleterious effects of the agonist.

Design and synthesis of 6-anilinoindazoles as selective inhibitors of c-Jun N-terminal kinase-3

The structure-based design and synthesis of a new series of c-Jun N-terminal kinase-3 inhibitors with selectivity against JNK1 and p38alpha is reported. The novel series of substituted 6-anilinoindazoles were designed based on a combination of hits from high throughput screening and X-ray crystal structure information of the compounds crystallized into the JNK3 ATP binding active site.

Biological basis for the use of botanicals in osteoarthritis and rheumatoid arthritis: a review

Osteoarthritis (OA) of the knee and hip is a debilitating disease affecting more women than men and the risk of developing OA increases precipitously with aging. Rheumatoid arthritis (RA), the most common form of inflammatory joint diseases, is a disease of unknown etiology and affects approximately 1% of the population worldwide, and unlike OA, generally involves many joints because of the systemic nature of the disease. Non-steroidal anti-inflammatory drugs (NSAIDs) are the first drugs of choice for the symptomatic treatment of both OA and RA. Because of the risks associated with the use of NSAIDs and other limitations, the use of alternative therapies, such as acupuncture and medicinal herbs, is on the rise and according to reports approximately 60-90% of dissatisfied arthritis patients are likely to seek the option of complementary and alternative medicine (CAM). This paper reviews the efficacy of some of the common herbs that have a history of human use and their anti-inflammatory or antiarthritic properties have been evaluated in animal models of inflammatory arthritis, in studies employing well defined and widely accepted in vitro models that use human chondrocytes/cartilage explants or in clinical trials. Available data suggests that the extracts of most of these herbs or compounds derived from them may provide a safe and effective adjunctive therapeutic approach for the treatment of OA and RA. This, in turn, argues for trials to establish efficacy and optimum dosage of these compounds for treating human inflammatory and degenerative joint diseases.

Design and synthesis of the first generation of novel potent, selective, and in vivo active (benzothiazol-2-yl)acetonitrile inhibitors of the c-Jun N-terminal kinase

Several lines of evidence support the hypothesis that c-Jun N-terminal kinase (JNKs) plays a critical role in a wide range of diseases including cell death (apoptosis)-related disorders (neurodegenerative diseases, brain, heart, and renal ischemia, epilepsy) and inflammatory disorders (multiple sclerosis, rheumatoid arthritis, inflammatory bowel diseases). Screening of our internal compound collection for inhibitors of JNK3 led to the identification of (benzothiazol-2-yl)acetonitrile derivatives as potent and selective JNK1, -2, -3 inhibitors. Starting from initial hit 1 (AS007149), the chemistry and initial structure-activity relationship (SAR) of this novel and unique kinase inhibitor template were explored. Investigation of the SAR rapidly revealed that the benzothiazol-2-ylacetonitrile pyrimidine core was crucial to retain a good level of potency on rat JNK3. Therefore, compound 6 was further optimized by exploring a number of distal combinations in place of the chlorine atom. This led to the observation that the presence of an aromatic group, two carbons away from the aminopyrimidine moiety and bearing substituents conferring hydrogen bond acceptor (HBA) properties, could improve the potency. Further improvements to the biological and biopharmaceutical profile of the most promising compounds were performed, resulting in the discovery of compound 59 (AS601245). The in vitro and in vivo anti-inflammatory potential of this new JNK inhibitor was investigated and found to demonstrate efficacy per oral route in an experimental model of rheumatoid arthritis (RA).

Substituting c-Jun N-terminal kinase-3 (JNK3) ATP-binding site amino acid residues with their p38 counterparts affects binding of JNK- and p38-selective inhibitors

c-Jun N-terminal kinase (JNK) activation is linked to the aberrant cell death in several neurodegenerative disorders, including Parkinson's and Alzheimer's disease. The sequence similarity among the JNK isoforms and fellow MAP kinase family member p38 has rendered the challenge of producing JNK3-specific inhibitors difficult. Using the crystal structure of JNK3 complexed with JNK inhibitors, potential compound-interacting amino acid residues were mutated to the corresponding residues in p38. The effects of these mutations on the kinetic parameters with three compounds were examined: a JNK3- (vs. p38-) selective inhibitor (SP 600125); a p38-selective inhibitor (Merck Z); and a potent combined JNK3 and p38 inhibitor (Merck Y). The data confirm the role of the JNK3 residues Ile-70 and Val-196 in both inhibitor and ATP-binding. Remarkably, the Ile-70-Val and Val-196-Ala mutations caused an increase and decrease, respectively, in the binding affinity of the p38-specific compound, Merck Z, of 10-fold. The Ile-70-Val effect may be due to the increased capacity of the active site to accommodate Merck Z, whereas the Val-196-Ala mutant may induce an unfavourable conformational change. Conservative mutations of the Asn-152 and Gln-155 residues inactivated the JNK3 enzyme, possibly interfering with protein folding in a critical hinge region of the protein.