Identification of a potent, selective, and orally active leukotriene a4 hydrolase inhibitor with anti-inflammatory activity

LTA 4H is a ubiquitously distributed 69 kDa zinc-containing cytosolic enzyme with both hydrolase and aminopeptidase activity. As a hydrolase, LTA 4H stereospecifically catalyzes the transformation of the unstable epoxide LTA 4 to the diol LTB 4, a potent chemoattractant and activator of neutrophils and a chemoattractant of eosinophils, macrophages, mast cells, and T cells. Inhibiting the formation of LTB 4 is expected to be beneficial in the treatment of inflammatory diseases such as inflammatory bowel disease (IBD), asthma, and atherosclerosis. We developed a pharmacophore model using a known inhibitor manually docked into the active site of LTA 4H to identify a subset of compounds for screening. From this work we identified a series of benzoxazole, benzthiazole, and benzimidazole inhibitors. SAR studies resulted in the identification of several potent inhibitors with an appropriate cross-reactivity profile and excellent PK/PD properties. Our efforts focused on further profiling JNJ 27265732, which showed encouraging efficacy in a disease model relevant to IBD.

Dual binding site inhibitors of B-RAF kinase

Computer aided modeling guided the design of a series of diarylimidazole compounds (11-22) intended to interact with both the ATP and adjacent allosteric binding domains of B-RAF kinase. Their ability to inhibit the function of B-RAF kinase and intracellular ERK1/2 phosphorylation were evaluated.

Pyrazole-based cathepsin S inhibitors with improved cellular potency

High potency pyrazole-based noncovalent inhibitors of human cathepsin S (CatS) were developed by modification of the benzo-fused 5-membered ring heterocycles found in earlier series of CatS inhibitors. Although substitutions on this heterocyclic framework had a moderate impact on enzymatic potency, dramatic effects on cellular activity were observed. Optimization afforded indole- and benzothiophene-derived analogues that were high affinity CatS inhibitors (IC(50)=20-40 nM) with good cellular potency (IC(50)=30-340 nM).

Potent, nonsteroidal selective androgen receptor modulators (SARMs) based on 8H-[1,4]oxazino[2,3-f]quinolin-8-ones

A series of androgen receptor modulators based on 8H-[1,4]oxazino[2,3-f]quinolin-8-ones was synthesized and evaluated in an androgen receptor transcriptional activation assay. The most potent analogues from the series exhibited single-digit nanomolar potency in vitro. Compound 18h demonstrated full efficacy in the maintenance of muscle weight, at 10 mg/kg, with reduced activity in prostate weight in an in vivo model of androgen action.

Novel series of potent, nonsteroidal, selective androgen receptor modulators based on 7H-[1,4]oxazino[3,2-g]quinolin-7-ones

Recent interest in orally available androgens has fueled the search for new androgens for use in hormone replacement therapy and as anabolic agents. In pursuit of this, we have discovered a series of novel androgen receptor modulators derived from 7H-[1,4]oxazino[3,2-g]quinolin-7-ones. These compounds were synthesized and evaluated in competitive binding assays and an androgen receptor transcriptional activation assay. A number of compounds from the series demonstrated single-digit nanomolar agonist activity in vitro. In addition, lead compound (R)-16e was orally active in established rodent models that measure androgenic and anabolic properties of these agents. In this assay, (R)-16e demonstrated full efficacy in muscle and only partially stimulated the prostate at 100 mg/kg. These data suggest that these compounds may be utilized as selective androgen receptor modulators or SARMs. This series represents a novel class of compounds for use in androgen replacement therapy.

Anti-inflammatory activity of a potent, selective leukotriene A4 hydrolase inhibitor in comparison with the 5-lipoxygenase inhibitor zileuton

Leukotriene A(4) hydrolase (LTA(4)H) catalyzes production of the proinflammatory lipid mediator, leukotriene (LT) B(4), which is implicated in a number of inflammatory diseases. We have identified a potent and selective inhibitor of both the epoxide hydrolase and aminopeptidase activities of recombinant human LTA(4)H (IC(50), approximately 10 nM). In a murine model of arachidonic acid-induced ear inflammation, the LTA(4)H inhibitor, JNJ-26993135 (1-[4-(benzothiazol-2-yloxy)-benzyl]-piperidine-4-carboxylic acid), dose-dependently inhibited ex vivo LTB(4) production in blood, in parallel with dose-dependent inhibition of neutrophil influx (ED(50), 1-3 mg/kg) and ear edema. In murine whole blood and in zymosan-induced peritonitis, JNJ-26993135 selectively inhibited LTB(4) production, without affecting cysteinyl leukotriene production, while maintaining or increasing production of the anti-inflammatory mediator, lipoxin (LX) A(4). The 5-lipoxygenase (5-LO) inhibitor zileuton showed inhibition of LTB(4), LTC(4), and LXA(4) production. Although zileuton inhibited LTB(4) production in the peritonitis model more effectively than the LTA(4)H inhibitor, the influx of neutrophils into the peritoneum after 1 and 2 h was significantly higher in zileuton- versus JNJ-26993135-treated animals. This difference may have been mediated by the increased LXA(4) levels in the presence of the LTA(4)H inhibitor. The selective inhibition of LTB(4) production by JNJ-26993135, while increasing levels of the anti-inflammatory mediator, LXA(4), may translate to superior therapeutic efficacy versus 5-LO or 5-LO-activating protein inhibitors in LTB(4)-mediated inflammatory diseases.

The SAR of 4-substituted (6,6-bicyclic) piperidine cathepsin S inhibitors

A series of competitive, reversible cathepsin S (CatS) inhibitors was investigated. An earlier disclosure detailed the discovery of the 4-(2-keto-1-benzimidazolinyl)-piperidin-1-yl moiety as an effective replacement for the 4-arylpiperazin-1-yl group found in our screening hit. Continued investigation into replacements for the 4-aryl piperazine resulted in the identification of potentially useful CatS inhibitors with enzymatic and cellular activity similar to that of JNJ 10329670 as disclosed in a previous publication.

Effects of Galanthus nivalis agglutinin (GNA) expressed in tomato leaves on larvae of the tomato moth Lacanobia oleracea (Lepidoptera: Noctuidae) and the effect of GNA on the development of the endoparasitoid Meteorus gyrator (Hymenoptera: Braconidae)

The effect of ingestion of transgenic tomato leaves expressing the plant lectin Galanthus nivalis agglutinin (GNA) on development of larvae of Lacanobia oleracea (Linnaeus) was studied under laboratory conditions. When L. oleracea larvae were fed on tomato line 14.1H, expressing approximately 2.0% GNA, significant increases in the mean larval weight and in the amount of food consumed were found. This resulted in an overall reduction in the mean development time to the pupal stage of approximately 7 days. A significant increase in the percentage survival to the adult moth was also recorded when newly hatched larvae were reared on transgenic tomato leaves (72%) compared to larvae reared on untransformed leaves (40%). The effects of ingestion of GNA by L. oleracea larvae, via artificial diet or the leaves of transgenic tomato or potato plants, on the subsequent development of its solitary endoparasitoid Meteorus gyrator (Thunberg) was also studied. No significant effects on the life cycle parameters of M. gyrator developing in L. oleracea fed on GNA-containing diets were observed. Experiments with transgenic potato plants indicated that the stadium of the host larvae at parasitism had a greater influence on M. gyrator development than the presence of GNA. Potential GNA-binding glycoproteins were detected in the gut and body tissues of larval M. gyrator. Despite detection in host tissues, GNA could not be detected in adult M. gyrator and therefore it is likely that at the time of pupation M. gyrator are able to void the GNA in the meconial pellet.

Preparation and Biological Evaluation of Indole, Benzimidazole, and Thienopyrrole Piperazine Carboxamides: Potent Human Histamine H4 Antagonists

Three series of H(4) receptor ligands, derived from indoly-2-yl-(4-methyl-piperazin-1-yl)-methanones, have been synthesized and their structure-activity relationships evaluated for activity at the H(4) receptor in competitive binding and functional assays. In all cases, substitution of small lipophilic groups in the 4 and 5-positions led to increased activity in a [(3)H]histamine radiolabeled ligand competitive binding assay. In vitro metabolism and initial pharmacokinetic studies were performed on selected compounds leading to the identification of indole 8 and benzimidazole 40 as potent H(4) antagonists with the potential for further development. In addition, both 8 and 40 demonstrated efficacy in in vitro mast cell and eosinophil chemotaxis assays.

Hydrolase activity in the venom of the pupal endoparasitic wasp, Pimpla hypochondriaca

Venom from the pupal endoparasitoid, Pimpla hypochondriaca has previously been shown to contain a mixture of biologically active molecules. Currently, P. hypochondriaca venom was examined for the presence of hydrolase activity. Six hydrolases were consistently detected using the API ZYM semiquantitative colourimetric kit. The main hydrolases detected were; acid phosphatase, beta-glucosidase, esterase, beta-galactosidase, esterase lipase, and lipase. The most rapid and intense colour reaction was detected for acid phosphatase. The pH optimum and the specific activity of venom acid phosphatase was determined using p-nitrophenol phosphate as a substrate and were 4.8 and 0.47 nmol p-nitrophenol/min/microg of venom protein, respectively. The acid phosphatase activity was inhibited in a dose dependent manner by sodium fluoride (IC(50) 4.2 x 10(-4) M), and by cocktail inhibitor 2 (CI 2). P. hypochondriaca venom has previously been shown to display potent cytotoxic activity towards Lacanobia oleracea haemocytes maintained in vitro. The contribution of acid phosphatase in venom to this cytotoxic activity was investigated by titrating venom against CI 2 prior to the addition of L. oleracea haemocytes. The results suggest that, despite the relatively high levels of acid phosphatase activity in venom, venom acid phosphatase plays no role in the antihaemocytic activity of P. hypochondriaca venom in vitro.

Influence of host size on the clutch size and developmental success of the gregarious ectoparasitoid Eulophus pennicornis (Nees)(Hymenoptera: Braconidae) attacking larvae of the tomato moth Lacanobia oleracea (L.) (Lepidoptera: Noctuidae)

The relationship between clutch size, host size and progeny survival in the gregarious ectoparasitoid Eulophus pennicornis was investigated in a number of scenarios. When naive parasitoids were exposed singly to Lacanobia oleracea hosts, clutch size was strongly correlated with the size of the host. However, survival of parasitoid offspring was negatively affected by the size of the host such that, in larger hosts, greater wasp larval and pupal mortality was recorded. As a result, no gain in realised fecundity was achieved through parasitizing L. oleracea larvae of mass >0.4 g over hosts of mass between 0.2–0.3 g. When exposed to populations of mixed stadium hosts (larvae in the fourth, fifth and sixth instars) during the entire lifespan of the wasp, host size and clutch size were correlated in early ovipositions (first three ovipositions). However, as the wasps aged, the relationship was much less apparent. When the parasitoid was restricted to foraging upon populations of sixth instar hosts only, no relationship between host size and clutch size was apparent. Exposure of the parasitoid to mixed and fixed stadium host populations showed that final(sixth) stadium hosts were the most frequently parasitized (ca. 96% of parasitized hosts) and that the average numbers of eggs laid per wasp, and the number of hosts parasitized, was significantly lower when the parasitoid was provided with fourth or fifth instar hosts only. The results indicate that the reproductive success of E. pennicornis does not increase with increasing host size or greater resource availability above a certain threshold, and that the physiological status of the host at the time of parasitism is the governing factor determining oviposition decisions and parasitoid survival. We conclude that E. pennicornis has been selected to preferentially utilize those hosts that maximize progeny survival and to adapt clutch size to the size of such hosts. We hypothesize that the major driver leading to the evolution of this strategy is the ability of the parasitoid to physiologically regulate the host.

Cathepsin S inhibitors as novel immunomodulators

Cathepsin S is one of the major cysteine proteases, and is expressed in the lysosome of antigen presenting cells; primarily dendritic cells, B-cells and macrophages. Cathepsin S is most well known for its critical function in the proteolytic digestion of the invariant chain chaperone molecules, thus controlling antigen presentation to CD4+ T-cells by major histocompatibility complex (MHC) class II molecules or to NK1.1+ T-cells via CD1 molecules. Cathepsin S also appears to participate in direct processing of exogenous antigens for presentation by MHC class II to CD4+ T-cells, or in cross-presentation by MHC class I molecules to CD8+ T-cells. In addition, although direct evidence is still lacking, in its secreted form cathepsin S is implicated in degradation of the extracellular matrix, which may contribute to the pathology of a number of diseases, including arthritis, atherosclerosis and chronic obstructive pulmonary disease. Therefore, inhibition of cathepsin S is a promising target for the development of novel therapeutics for a variety of indications.

Interactions between the solitary endoparasitoid, Meteorus gyrator (Hymenoptera: Braconidae) and its host, Lacanobia oleracea (Lepidoptera: Noctuidae), infected with the entomopathogenic microsporidium, Vairimorpha necatrix (Microspora: Microsporidia)

Infection of Lacanobia oleracea (Linnaeus) larvae with the microsporidium Vairimorpha necatrix (Kramer) resulted in significant effects on the survival and development of the braconid parasitoid, Meteorus gyrator (Thunberg). Female M. gyrator did not show any avoidance of V. necatrix-infected hosts when they were selecting hosts for oviposition. When parasitism occurred at the same time as infection by the pathogen, or up to four days later, no significant detrimental effects on the parasitoid were observed. However, when parasitism occurred six to eight days after infection, a greater proportion (12.5-14%) of hosts died before parasitoid larvae egressed. Successful eclosion of adult wasps was also reduced. When parasitism and infection were concurrent, parasitoid larval development was significantly faster in infected hosts, and cocoons were significantly heavier. However, as the time interval between infection and parasitism increased, parasitoid larval development was significantly extended by up to two days, and the cocoons formed were significantly (c. 20%) smaller. Vairimorpha necatrix spores were ingested by the developing parasitoid larvae, accumulated in the occluded midgut, and were excreted in the meconium upon pupation.

Discovery and SAR studies of a novel series of noncovalent cathepsin S inhibitors

A novel series of competitive, reversible cathepsin S (CatS) inhibitors was discovered and optimized. The 4-(2-keto-1-benzimidazolinyl)-piperidin-1-yl moiety was found to be an effective replacement for the 4-arylpiperazin-1-yl group found in our earlier series of CatS inhibitors. This replacement imparted improved PK properties as well as decreased off-target activity. Optimization of the ketobenzimidazole moiety led to the discovery of the lead compound JNJ 10329670, which represents a novel class of selective, noncovalent, reversible, and orally bioavailable inhibitors of cathepsin S.

Hyperphagocytic haemocytes in Manduca sexta

We have discovered a new type of haemocyte in the larval stage of the tobacco hornworm moth Manduca sexta that has extreme phagocytic ability; each cell can engulf up to 500 bacteria. This level of phagocytosis may be unprecedented among animal cells. Although these hyperphagocytic cells (HP) only represent about 1% of the circulating haemocytes, they are responsible for sequestering the majority of the bacteria by circulating haemocytes when non-pathogenic, heat-killed Escherichia coli are injected into the haemolymph. Extreme phagocytosis by HP is not limited to Gram-negative bacteria since heat-killed Staphylococcus aureus as well as positively and negatively charged microspheres are also highly phagocytosed. Evidence is presented to show that phagocytosis by HP is involved in the early stages of nodule formation in infected insects. In addition, HP are also present in non-infected insects, characterised by their distinctive spreading morphology, which becomes impaired following hyperphagocytosis of bacteria. This is the first time that a dedicated "professional" phagocytic class of haemocyte has been reported for an invertebrate. The importance of these specialised cell types in the M. sexta immune response and their role in nodule formation is discussed.

Nonpeptidic, noncovalent inhibitors of the cysteine protease cathepsin S

The first nonpeptidic, noncovalent inhibitors of the cysteine protease cathepsin S (CatS) are described. Electronic database searching using the program DOCK generated a screening set of potential CatS inhibitors from which two lead structures were identified as promising starting points for a drug discovery effort. Lead optimization afforded potent (IC(50) < 50 nM) and selective inhibitors of CatS demonstrating cellular activity and reversibility of enzyme inhibition.

Venom from the pupal endoparasitoid, Pimpla hypochondriaca, increases the susceptibility of larval Lacanobia oleracea to the entomopathogens Bacillus cereus and Beauveria bassiana

Cellular immune responses in insects protect them against parasites and pathogens that enter their hemocoel. Venom from the solitary pupal endoparasitoid, Pimpla hypochondriaca, has previously been shown to suppress certain key, cell-mediated immune responses of Lacanobia oleracea. Experiments were performed to determine if L. oleracea larvae injected with P. hypochondriaca venom would be more susceptible to Bacillus cereus, or Beauveria bassiana, when these microorganisms were subsequently injected. Mortality due to B. cereus (approximately 15 colony-forming units [CFU]/larva) and B. bassiana (approximately 2.4 x 10(3) conidia/larva) was enhanced by prior injection of 4 microg of venom. In addition, injection of venom/Dulbecco's phosphate-buffered saline (DPBS) or DPBS/B. bassiana reduced the rate at which larvae gained weight compared to control larvae. However, the greatest reduction in weight was recorded for larvae that had been injected with venom/B. bassiana conidia.

Histamine H4 receptor mediates eosinophil chemotaxis with cell shape change and adhesion molecule upregulation

1. During mast cell degranulation, histamine is released in large quantities. Human eosinophils were found to express histamine H(4) but not H(3) receptors. The possible effects of histamine on eosinophils and the receptor mediating these effects were investigated in our studies. 2. Histamine (0.01-30 microm) induced a rapid and transient cell shape change in human eosinophils, but had no effects on neutrophils. The maximal shape change was at 0.3 microm histamine with EC(50) at 19 nm. After 60 min incubation with 1 microm histamine, eosinophils were desensitized and were refractory to shape change response upon histamine restimulation. Histamine (0.01-1 microm) also enhanced the eosinophil shape change induced by other chemokines. 3. Histamine-induced eosinophil shape change was mediated by the H(4) receptor. This effect was completely inhibited by H(4) receptor-specific antagonist JNJ 7777120 (IC(50) 0.3 microm) and H(3)/H(4) receptor antagonist thioperamide (IC(50) 1.4 microm), but not by selective H(1), H(2) or H(3) receptor antagonists. H(4) receptor agonists imetit (EC(50) 25 nm) and clobenpropit (EC(50) 72 nm) could mimic histamine effect in inducing eosinophil shape change. 4. Histamine (0.01-100 microm) induced upregulation of adhesion molecules CD11b/CD18 (Mac-1) and CD54 (ICAM-1) on eosinophils. This effect was mediated by the H(4) receptor and could be blocked by H(4) receptor antagonists JNJ 7777120 and thioperamide. 5. Histamine (0.01-10 microm) induced eosinophil chemotaxis with an EC(50) of 83 nm. This effect was mediated by the H(4) receptor and could be blocked by H(4) receptor antagonists JNJ 7777120 (IC(50) 86 nm) and thioperamide (IC(50) 519 nm). Histamine (0.5 microm) also enhanced the eosinophil shape change induced by other chemokines. 6. In conclusion, we have demonstrated a new mechanism of eosinophil recruitment driven by mast cells via the release of histamine. Using specific histamine receptor ligands, we have provided a definitive proof that the H(4) receptor mediates eosinophil chemotaxis, cell shape change and upregulation of adhesion molecules. The effect of H(4) receptor antagonists in blocking eosinophil infiltration could be valuable for the treatment of allergic diseases. The histamine-induced shape change and upregulation of adhesion molecules on eosinophils can serve as biomarkers for clinical studies of H(4) receptor antagonists.

A potent and selective histamine H4 receptor antagonist with anti-inflammatory properties

Histamine mediates its physiological function through binding to four known histamine receptors. Here, we describe the first selective antagonist of the histamine H4 receptor, the newest member of the histamine receptor family, and provide evidence that such antagonists have anti-inflammatory activity in vivo. 1-[(5-chloro-1H-indol-2-yl)carbonyl]-4-methylpiperazine (JNJ 7777120) has a K(i) of 4.5 nM versus the human receptor and a pA(2) of 8.1. It is equipotent against the human, mouse, and rat receptors. It exhibits at least 1000-fold selectivity over H1, H2, or H3 receptors and has no cross-reactivity against 50 other targets. This compound has an oral bioavailability of approximately 30% in rats and 100% in dogs, with a half-life of approximately 3 h in both species. JNJ 7777120 blocks histamine-induced chemotaxis and calcium influx in mouse bone marrow-derived mast cells. In addition, it can block the histamine-induced migration of tracheal mast cells from the connective tissue toward the epithelium in mice. JNJ 7777120 significantly blocks neutrophil infiltration in a mouse zymosan-induced peritonitis model. This model is reported to be mast cell-dependent, which suggests that the compound effect may be mediated by mast cells. These results indicate that the histamine H4 receptor plays a role in the inflammatory process. Selective H4 receptor antagonists like JNJ 7777120 may have the potential to be useful in treating inflammation in humans.

Identification of a Potent and Selective Noncovalent Cathepsin S Inhibitor

Cathepsin S is considered crucial for normal presentation of major histocompatibility complex (MHC) class II-restricted antigens by antigen presenting cells to CD4+ T cells. It is a key enzyme for the degradation of the class II-associated invariant chain, a process that is required for effective antigen loading of class II molecules. Here, we report a selective, orally available, high-affinity cathepsin S inhibitor, 1-[3-[4-(6-Chloro-2,3-dihydro-3-methyl-2-oxo-1H-benzimidazol-1-yl)-1-piperidinyl]propyl]-4,5,6,7-tetrahydro-5-(methylsulfonyl)-3-[4-(trifluoromethyl)phenyl]-1H-pyrazolo[4,3-c]pyridine. (JNJ 10329670), that represents a novel class of immunosuppressive compounds. JNJ 10329670 is a highly potent (Ki of approximately 30 nM), nonpeptidic, noncovalent inhibitor of human cathepsin S, but it is much less active against the mouse, dog, monkey, and bovine enzymes. The compound is inactive against other proteases, including the closely related cathepsins L, F, and K. This selectivity makes JNJ 10329670 an excellent tool for exploring the role of cathepsin S in human systems. Treatment of human B cell lines and primary human dendritic cells with JNJ 10329670 resulted in the accumulation of the p10 fragment of the invariant chain (IC50 of approximately 1 microM). In contrast, inhibition of invariant chain proteolysis was much less effective in a human monocytic cell line, suggesting that other enzymes may degrade the invariant chain in this cell type. JNJ 10329670 was shown to block the proteolysis of the invariant chain in vivo by using immunocompromised mice injected with human peripheral blood mononuclear cells (PBMCs). Furthermore, this inhibitor blocks the presentation of tetanus toxoid and giant ragweed by human PBMCs. The properties of JNJ 10329670 make it a candidate for immunosuppressive therapy of allergies and autoimmune diseases.