N-((8-hydroxy-5-substituted-quinolin-7-yl)(phenyl)methyl)-2-phenyloxy/amino-acetamide inhibitors of ADAMTS-5 (Aggrecanase-2)

Conversion of 2-methyl-4-styrylquinolines into 2,4-distyrylquinolines: synthesis, and spectroscopic and structural characterization of five examples

Four new 2,4-distyrylquinolines and one 2-styryl-4-[2-(thiophen-2-yl)vinyl]quinoline have been synthesized using indium trichloride condensation reactions between aromatic aldehydes and the corresponding 2-methylquinolines, which were themselves prepared using Friedländer annulation reactions between mono- or diketones and (2-aminophenyl)chalcones: the products have all been fully characterized by spectroscopic and crystallographic methods. 2,4-Bis[(E)-styryl]quinoline, C25H19N, (IIa), and its dichloro analogue, 2-[(E)-2,4-dichlorostyryl]-4-[(E)-styryl]quinoline, C25H17Cl2N, (IIb), exhibit different orientations of the 2-styryl unit relative to the quinoline nucleus. In each of the 3-benzoyl analogues {2-[(E)-4-bromostyryl]-4-[(E)-styryl]quinolin-3-yl}(phenyl)methanone, C32H22BrNO, (IIc), {2-[(E)-4-bromostyryl]-4-[(E)-4-chlorostyryl]quinolin-3-yl}(phenyl)methanone, C32H21BrClNO, (IId), and {2-[(E)-4-bromostyryl]-4-[(E)-2-(thiophen-2-yl)vinyl]quinolin-3-yl}(phenyl)methanone, C30H20BrNOS, (IIe), the orientation of the 2-styryl unit is similar to that in (IIa), but the orientation of the 4-arylvinyl units show considerable variation. The thiophene unit in (IIe) is disordered over two sets of atomic sites having occupancies of 0.926 (3) and 0.074 (3). There are no hydrogen bonds of any kind in the structure of (IIa), but in (IId), a single C-H...O hydrogen bond links the molecules into cyclic centrosymmetric R22(20) dimers. A combination of C-H...N and C-H...π hydrogen bonds links the molecules of (IIb) into a three-dimensional framework structure. A combination of three C-H...π hydrogen bonds links the molecules of (IIc) into sheets, and a combination of C-H...O and C-H...π hydrogen bonds forms sheets in (IIe). Comparisons are made with the structures of some related compounds.

Targeting Aggrecanases for Osteoarthritis Therapy: From Zinc Chelation to Exosite Inhibition

Osteoarthritis (OA) is the most common degenerative joint disease. In 1999, two members of the A Disintegrin and Metalloproteinase with Thrombospondin Motifs (ADAMTS) family of metalloproteinases, ADAMTS4 and ADAMTS5, or aggrecanases, were identified as the enzymes responsible for aggrecan degradation in cartilage. The first aggrecanase inhibitors targeted the active site by chelation of the catalytic zinc ion. Due to the generally disappointing performance of zinc-chelating inhibitors in preclinical and clinical studies, inhibition strategies tried to move away from the active-site zinc in order to improve selectivity. Exosite inhibitors bind to proteoglycan-binding residues present on the aggrecanase ancillary domains (called exosites). While exosite inhibitors are generally more selective than zinc-chelating inhibitors, they are still far from fulfilling their potential, partly due to a lack of structural and functional data on aggrecanase exosites. Filling this gap will inform the design of novel potent, selective aggrecanase inhibitors.

Recent Progress in the Synthesis of Quinolines

BACKGROUND

Quinoline-containing compounds present in both natural and synthetic products are an important class of heterocyclic compounds. Many of the substituted quinolines have been used in various areas including medicine as drugs. Compounds with quinoline skeleton possess a wide range of bioactivities such as antimalarial, anti-bacterial, anthelmintic, anticonvulsant, antiviral, anti-inflammatory, and analgesic activity. Due to such a wide range of applicability, the synthesis of quinoline derivatives has attracted a lot of attention of chemists to develop effective methods. Many known methods have been expanded and improved. Furthermore, various new methods for quinoline synthesis have been established. This review will focus on considerable studies on the synthesis of quinolines date which back to 2014.

OBJECTIVE

In this review, we discussed recent achievements on the synthesis of quinoline compounds. Some classical methods have been modified and improved, while other new methods have been developed. A vast variety of catalysts were used for these transformations. In some studies, quinoline synthesis reaction mechanisms were also displayed.

CONCLUSION

Many methods for the synthesis of substituted quinoline rings have been developed recently. Over the past five years, the majority of those reported have been based on cycloisomerization and cyclization processes. Undoubtedly, more imaginative approaches to quinoline synthesis will appear in the literature in the near future. The application of known methods to natural product synthesis is probably the next challenge in the field.

Design, Synthesis, and SAR of Novel 2-Glycinamide Cyclohexyl Sulfonamide Derivatives against Botrytis cinerea

N-(2-trifluoromethyl-4-chlorophenyl)-2-oxocyclohexyl sulfonamide (chesulfamide) is in the limelight as a novel fungicide, and has fungicidal activity against Botrytis cinerea. For exploring more novel structures, 33 new compounds were synthesized by N-alkylation and acid–amine coupling reactions with chesulfamide as the core moiety, and their structures were characterized and established by ¹H-NMR, ¹³C-NMR, MS, and elemental analysis. The structure of (1R,2S)-2-(2-(N-(4-chloro-2-trifluoromethylphenyl)sulfamoyl)-cyclohexylamino)-N-(2-trifluoromethylphenyl) acetamide (II-19) was defined by X-ray single crystal diffraction. The in vivo and in vitro fungicidal activities against B. cinerea were evaluated. The bioassay results of mycelial growth demonstrated that most compounds exhibited excellent inhibitory activity against B. cinerea at 50 μg mL⁻¹, and 7 compounds showed lower EC₅₀ values than boscalid (EC₅₀ = 4.46 μg mL⁻¹) against B. cinerea (CY-09). In cucumber pot experiment, the inhibitory rates of four compounds (II-4, II-5, II-12, and II-13) against B. cinerea were 90.48, 93.45, 92.86, and 91.07, which were better than cyprodinil (88.69%), the best performing of all controls. In tomato pot experiment, the control efficacy of two analogs (II-8 and II-15) were 87.98 and 87.97% at 200 μg mL⁻¹, which were significantly higher than boscalid (78.10%). Most compounds have an excellent fungicidal effect on B. cinerea, with potential as a lead compound for developing new pesticides.

Roles of microRNA and signaling pathway in osteoarthritis pathogenesis

Osteoarthritis (OA) is a common chronic degenerative joint disease, with complicated pathogenic factors and undefined pathogenesis. Various signaling pathways play important roles in OA pathogenesis, including genetic expression, matrix synthesis and degradation, cell proliferation, differentiation, apoptosis, and so on. MicroRNA (miRNA) is a class of non-coding RNA in Eukaryon, regulating genetic expression on the post-transcriptional level. A great number of miRNAs are involved in the development of OA, and are closely associated with different signaling pathways. This article reviews the roles of miRNAs and signaling pathways in OA, looking toward having a better understanding of its pathogenesis mechanisms and providing new therapeutic targets for its treatment.

Enol ethers as carbonyl surrogates in a modification of the Povarov synthesis of 3-aryl quinolines and their anti-Toxoplasma activity

A novel method for the preparation of 2-carboxyl-3-aryl quinoline derivatives from anilines, ethyl glyoxalate and enol ethers as phenylacetaldehyde surrogates is reported.

Inhibition of aggrecanases as a therapeutic strategy in osteoarthritis

Over the last decade, there has been a large effort to target aggrecanases, which are responsible for the degradation of the aggrecan in the extracellular matrix of joints, in order to hopefully lead to new treatments for osteoarthritis. Only a few inhibitors have been effective in explants or rodent models and thus only a few have reached the clinic, none of which have proven to be effective. In this article, a survey of chemical series is described, covering historical and recent inhibitors and highlighting how some of their problems were resolved, with a critical overview of the challenges encountered. A large effort should be undertaken in designing smaller compounds with higher residence times, defining new interaction sites on the aggrecanases and exploiting target flexibility.

Altered expression of circulating microRNA in plasma of patients with primary osteoarthritis and in silico analysis of their pathways

Objective

To analyze a set of circulating microRNA (miRNA) in plasma from patients with primary Osteoarthritis (OA) and describe the biological significance of altered miRNA in OA based on an in silico analysis of their target genes.

Methods

miRNA expression was analyzed using TaqMan Low Density Arrays and independent assays. The search for potential messenger RNA (mRNA) targets of the differentially expressed miRNA was performed by means of the miRWalk and miRecords database; we conducted the biological relevance of the predicted miRNA targets by pathway analysis with the Reactome and DAVID databases.

Results

We measured the expression of 380 miRNA in OA; 12 miRNA were overexpressed under the OA condition (p value, ≤0.05; fold change, >2). These results were validated by the detection of some selected miRNA by quantitative PCR (qPCR). In silico analysis showed that target messenger RNA (mRNA) were potentially regulated by these miRNA, including genes such as SMAD1, IL-1B, COL3A, VEGFA, and FGFR1, important in chondrocyte maintenance and differentiation. Some metabolic pathways affected by the miRNA: mRNA ratio are signaling Bone morphogenetic proteins (BMP), Platelet-derived growth factor (PDGF), and Nerve growth factor (NGF), these latter two involved in the process of pain.

Conclusions

We identified 12 miRNA in the plasma of patients with primary OA. Specific miRNA that are altered in the disease could be released into plasma, either due to cartilage damage or to an inherent cellular mechanism. Several miRNA could regulate genes and pathways related with development of the disease; eight of these circulating miRNA are described, to our knowledge, for first time in OA.

The amelioration of cartilage degeneration by ADAMTS-5 inhibitor delivered in a hyaluronic acid hydrogel

Degradation of proteoglycan is the key early event in the development of osteoarthritis (OA). The aggrecanase ADAMTS-5 has been identified as the major enzyme responsible for the degradation and thus is an attractive therapeutic target for OA. However, currently there is no report on using an ADAMTS-5 inhibition strategy for OA treatment. The present study aimed to investigate the synergic effect of combining an ADAMTS-5 inhibitor (114810) with a hyaluronic acid hydrogel (HAX) for OA therapeutics. Two OA models were induced by surgically creating an osteochondral defect or removing the anterior cruciate ligament (ACL) in Sprague-Dawley rats. Human OA cartilage was obtained from total joint replacement patients. Both human and rat OA cartilage showed marked proteoglycan loss with significantly increased ADAMTS-5 expression. The effectiveness of ADAMTS-5 inhibition by 114810 was confirmed by a cartilage explants assay in vitro, which showed that the 114810 halted the aggrecanase-mediated (374)ARGS neoepitope released from aggrecan induced by IL-1β stimulation. The in vivo effect of ADAMTS-5 inhibition was assessed by the articular injection of HAX with 114810 into OA knee joints. Evaluated eight weeks after injection, 114810 with HAX significantly promoted the in vivo cartilage healing in the osteochondral defect model, and prevented the progression of degenerative changes in the ACL model. Our results confirmed that ADAMTS-5 is an effective target for OA treatment, and the intra-articular injection of an ADAMTS-5 inhibitor within HAX gel could be a promising strategy for OA treatment.

Current and emerging therapeutic strategies for preventing inflammation and aggrecanase-mediated cartilage destruction in arthritis

Arthritis is a multifactorial disease for which current therapeutic intervention with high efficacy remains challenging. Arthritis predominately affects articular joints, and cartilage deterioration and inflammation are key characteristics. Current therapeutics targeting inflammatory responses often cause severe side effects in patients because of the systemic inhibition of cytokines or other global immunosuppressive activities. Furthermore, a lack of primary response or failure to sustain a response to treatment through acquired drug resistance is an ongoing concern. Nevertheless, treatments such as disease-modifying anti-rheumatic drugs, biological agents, and corticosteroids have revealed promising outcomes by decreasing pain and inflammation in patients and in some cases reducing radiographic progression of the disease. Emerging and anecdotal therapeutics with anti-inflammatory activity, alongside specific inhibitors of the A Disintegrin-like And Metalloproteinase domain with Thrombospondin-1 repeats (ADAMTS) cartilage-degrading aggrecanases, provide promising additions to current arthritis treatment strategies. Thus, it is paramount that treatment strategies be optimized to increase efficacy, reduce debilitating side effects, and improve the quality of life of patients with arthritis. Here, we review the current strategies that attempt to slow or halt the progression of osteoarthritis and rheumatoid arthritis, providing an up-to-date summary of pharmaceutical treatment strategies and side effects. Importantly, we highlight their potential to indirectly regulate ADAMTS aggrecanase activity through their targeting of inflammatory mediators, thus providing insight into a mechanism by which they might inhibit cartilage destruction to slow or halt radiographic progression of the disease. We also contrast these with anecdotal or experimental administration of statins that could equally regulate ADAMTS aggrecanase activity and are available to arthritis sufferers worldwide. Finally, we review the current literature regarding the development of synthetic inhibitors directed toward the aggrecanases ADAMTS4 and ADAMTS5, a strategy that might directly inhibit cartilage destruction and restore joint function in both rheumatoid arthritis and osteoarthritis.

Molecular mechanisms of the cartilage-specific microRNA-140 in osteoarthritis

Osteoarthritis (OA) is the most widespread chronic degenerative joint disorder, characterized by progressive destruction of articular cartilage, subchondral bone alterations, formation of osteophytes and synovitis. MicroRNAs (miRNAs) are a class of endogenous and non-coding single-strand RNAs with a length of about 22 nucleotides, and many of them are evolutionarily conserved. miRNAs have been implicated in the process of development and pathogenesis of diseases, and tissue-specific miRNA functional studies in mice have revealed both pathogenic and protective functions. miRNA-140 (miR-140) was shown to be specifically expressed in cartilage tissues in developing zebrafish and mouse embryos during the development of both long and flat bones. Recently, miR-140 has been reported in many studies to play significant roles in OA pathogenesis. Although the previous results were not always consistent, the molecular mechanisms of the regulation and dual function of miR-140 in cartilage homeostasis and development have been established in previous studies. Further elucidation of the molecular basis of miR-140 will uncover synergistic inhibitory effects of miR-140 and other factors on OA pathogenesis, and provide a novel means of treating OA disease.

Arylsulfonamide inhibitors of aggrecanases as potential therapeutic agents for osteoarthritis: synthesis and biological evaluation

Aggrecanases, in particular aggrecanase-2 (ADAMTS-5), are considered the principal proteases responsible for aggrecan degradation in osteoarthritis. For this reason, considerable effort has been put on the discovery and development of aggrecanase inhibitors able to slow down or halt the progression of osteoarthritis. We report herein the synthesis and biological evaluation of a series of arylsulfonamido-based hydroxamates as aggrecanase inhibitors. Compound 18 was found to have a nanomolar activity for ADAMTS-5, ADAMTS-4 and MMP-13 and high selectivity over MMP-1 and MMP-14. Furthermore, this compound proved to be effective in blocking ex vivo cartilage degradation without having effect on cell cytotoxicity.

Quinoline: A versatile heterocyclic

Quinoline or 1-aza-naphthalene is a weak tertiary base. Quinoline ring has been found to possess antimalarial, anti-bacterial, antifungal, anthelmintic, cardiotonic, anticonvulsant, anti-inflammatory, and analgesic activity. Quinoline not only has a wide range of biological and pharmacological activities but there are several established protocols for the synthesis of this ring. The article aims at highlighting these very diversities of the ring.

Impact of inflammation on the osteoarthritic niche: implications for regenerative medicine

Osteoarthritis (OA) is the most common form of arthritis worldwide and is the sixth leading cause of disability. It costs the UK economy approximately 1% of gross national product per annum. With an aging population, the cost of chronic conditions such as OA continues to rise. Historically, treatments for OA have been limited to painkillers, physiotherapy and joint injections. When these fail, patients are referred for joint replacement surgery. With the advent of tissue engineering strategies aimed at generating new bone and cartilage for repair of osteochondral defects, there has been considerable interest in exploiting these techniques to devise new treatments for OA. To date, little consideration has been given to the OA niche and attendant inflammatory milieu for any regenerative skeletal strategy. This review highlights the importance of understanding the osteoarthritic niche in order to modify existing tissue engineering and regenerative medicine strategies for the future treatment of OA.

Novel role of ADAMTS-5 protein in proteoglycan turnover and lipoprotein retention in atherosclerosis

Atherosclerosis is initiated by the retention of lipoproteins on proteoglycans in the arterial intima. However, the mechanisms leading to proteoglycan accumulation and lipoprotein retention are poorly understood. In this study, we set out to investigate the role of ADAMTS-5 (a disintegrin and metalloprotease with thrombospondin motifs-5) in the vasculature. ADAMTS-5 was markedly reduced in atherosclerotic aortas of apolipoprotein E-null (apoE^−/−) mice. The reduction of ADAMTS-5 was accompanied by accumulation of biglycan and versican, the major lipoprotein-binding proteoglycans, in atherosclerosis. ADAMTS-5 activity induced the release of ADAMTS-specific versican (DPEAAE⁴⁴¹) and aggrecan (³⁷⁴ALGS) fragments as well as biglycan and link protein from the aortic wall. Fibroblast growth factor 2 (FGF-2) inhibited ADAMTS-5 expression in isolated aortic smooth muscle cells and blocked the spontaneous release of ADAMTS-generated versican and aggrecan fragments from aortic explants. In aortas of ADAMTS-5-deficient mice, DPEAAE⁴⁴¹ versican neoepitopes were not detectable. Instead, biglycan levels were increased, highlighting the role of ADAMTS-5 in the catabolism of vascular proteoglycans. Importantly, ADAMTS-5 proteolytic activity reduced the LDL binding ability of biglycan and released LDL from human aortic lesions. This study provides the first evidence implicating ADAMTS-5 in the regulation of proteoglycan turnover and lipoprotein retention in atherosclerosis.

Discovery of potent and selective inhibitors of human platelet-type 12- lipoxygenase

We report the discovery of novel small molecule inhibitors of platelet-type 12-human lipoxygenase, which display nanomolar activity against the purified enzyme, using a quantitative high-throughput screen (qHTS) on a library of 153607 compounds. These compounds also exhibit excellent specificity, >50-fold selectivity vs the paralogues, 5-human lipoxygenase, reticulocyte 15-human lipoxygenase type-1, and epithelial 15-human lipoxygenase type-2, and >100-fold selectivity vs ovine cyclooxygenase-1 and human cyclooxygenase-2. Kinetic experiments indicate this chemotype is a noncompetitive inhibitor that does not reduce the active site iron. Moreover, chiral HPLC separation of two of the racemic lead molecules revealed a strong preference for the (-)-enantiomers (IC(50) of 0.43 ± 0.04 and 0.38 ± 0.05 μM) compared to the (+)-enantiomers (IC(50) of >25 μM for both), indicating a fine degree of selectivity in the active site due to chiral geometry. In addition, these compounds demonstrate efficacy in cellular models, which underscores their relevance to disease modification.

MicroRNA in Osteoarthritis

Osteoarthritis (OA) is the most prevalent degenerative joint disease and is accompanied by pain and joint dysfunction. Its clinical treatment tends to be unsatisfactory. Novel targets in OA include genes that are involved in OA pathophysiology and have been discovered using gene network, epigenetic and microRNA (miRNA) approaches. miRNA has been implicated in important cellular processes such as lipid metabolism, apoptosis, differentiation and organ development. The importance of miRNA regulation in cellular function is becoming increasingly clear as new miRNA targets are revealed. The present review summarizes the current evidence of the important role played by miRNA in determining the complex gene expression patterns of OA chondrocytes and their role in the regulation of transcription, and possible demethylation mechanisms that might be applicable in OA. In summary, miRNA may have important diagnostic and therapeutic potential, and might provide a novel means of treating OA.

Advances in the development of novel aggrecanase inhibitors

IMPORTANCE OF THE FIELD

Aggrecanases are members of a disintegrin and metalloprotease with thrombospondin motif family of zinc metalloproteases involved in the cleavage of aggrecan fragments in cartilage. Inhibition of aggrecanase activity in osteoarthritis (OA) patients should both provide symptomatic relief of OA pain as well as OA disease modification.

AREAS COVERED IN THIS REVIEW

This article reviews patent applications containing compounds claimed to have aggrecanase inhibitory activity which were published from 2005 through August 2010.

WHAT THE READER WILL GAIN

Readers will be informed of the different classes of disclosed aggrecanase inhibitors and gain an understanding of how these series interact with the various components of the catalytic sites of these enzymes.

TAKE HOME MESSAGE

Patenting in the area of aggrecanase inhibitors has been modest. Most of the patented chemical matter are lipophilic, acidic compounds with molecular mass (MM) > 400: properties that usually do not imbue good systemic compound exposure. Possibly due to these properties and poor exposure, there are no late state aggrecanase compounds in the clinic to our knowledge. The future development of lower MM, less acidic aggrecanase inhibitors with good pharmacokinetic profiles could increase activity in this field as aggrecanases are well-validated targets for diseases such as OA.

Small molecules for bone diseases

IMPORTANCE OF THE FIELD

Bones play many roles in the body, providing structure, protecting organs, anchoring muscles and storing calcium. Over 100 million people worldwide suffer from bone diseases, mainly osteoporosis, cancer-related bone loss, osteoarthritis and inflammatory arthritis. Osteoporosis itself has no specific symptoms, and the main consequence is the increased risk of bone fractures. Therefore, the prevention of bone diseases is important to maintain the quality of life in the human society. However, treatment options are still insufficient.

AREAS COVERED IN THIS REVIEW

This review article gives a summary of the low molecular mass modulators of bone diseases targets disclosed in patent applications and articles, mainly during the last 5 years.

WHAT THE READER WILL GAIN

Readers will rapidly gain an overview of these modulators not only for historical targets, but also of emerging and re-visited targets. Readers will also be able to see the current research trend and the main players in this field.

TAKE HOME MESSAGE

Drug discovery for bone diseases has made progress in the last years. The research area has dynamically shifted from historical targets (bisphosphonate, parathyroid hormone and calcitonin) to newly confirmed targets or targets re-visited which were biologically validated in the past. Cathepsin K inhibitors should be very close to launching in the market.

New molecular targets for the treatment of osteoarthritis

Osteoarthritis (OA) is a chronic degenerative joint disorder characterized by destruction of the articular cartilage, subchondral bone alterations and synovitis. Current treatments are focused on symptomatic relief but they lack efficacy to control the progression of this disease which is a leading cause of disability. Therefore, the development of effective disease-modifying drugs is urgently needed. Different initiatives are in progress to define the molecular mechanisms involved in the initiation and progression of OA. These studies support the therapeutic potential of pathways relevant in joint metabolism such as Wnt/beta-catenin, discoidin domain receptor 2 or proteinase-activated receptor 2. The dysregulation in cartilage catabolism and subchondral bone remodeling could be improved by selective inhibitors of matrix metalloproteinases, aggrecanases and other proteases. Another approach would favor the activity of anabolic processes by using growth factors or regulatory molecules. Recent studies have also revealed the role of oxidative stress and synovitis in the progression of this disease, supporting the development of a number of inhibitory strategies. Novel targets in OA are represented by genes involved in OA pathophysiology discovered using gene network, epigenetic and microRNA approaches. Further insights into the molecular mechanisms involved in OA initiation and progression may lead to the development of new therapies able to control joint destruction and repair.

Cartilage homeostasis in health and rheumatic diseases

As the cellular component of articular cartilage, chondrocytes are responsible for maintaining in a low-turnover state the unique composition and organization of the matrix that was determined during embryonic and postnatal development. In joint diseases, cartilage homeostasis is disrupted by mechanisms that are driven by combinations of biological mediators that vary according to the disease process, including contributions from other joint tissues. In osteoarthritis (OA), biomechanical stimuli predominate with up-regulation of both catabolic and anabolic cytokines and recapitulation of developmental phenotypes, whereas in rheumatoid arthritis (RA), inflammation and catabolism drive cartilage loss. In vitro studies in chondrocytes have elucidated signaling pathways and transcription factors that orchestrate specific functions that promote cartilage damage in both OA and RA. Thus, understanding how the adult articular chondrocyte functions within its unique environment will aid in the development of rational strategies to protect cartilage from damage resulting from joint disease. This review will cover current knowledge about the specific cellular and biochemical mechanisms that regulate cartilage homeostasis and pathology.