JT002, a small molecule inhibitor of the NLRP3 inflammasome for the treatment of autoinflammatory disorders

The NLRP3 inflammasome is an intracellular, multiprotein complex that promotes the auto-catalytic activation of caspase-1 and the subsequent maturation and secretion of the pro-inflammatory cytokines, IL-1β and IL-18. Persistent activation of the NLRP3 inflammasome has been implicated in the pathophysiology of a number of inflammatory and autoimmune diseases, including neuroinflammation, cardiovascular disease, non-alcoholic steatohepatitis, lupus nephritis and severe asthma. Here we describe the preclinical profile of JT002, a novel small molecule inhibitor of the NLRP3 inflammasome. JT002 potently reduced NLRP3-dependent proinflammatory cytokine production across a number of cellular assays and prevented pyroptosis, an inflammatory form of cell death triggered by active caspase-1. JT002 demonstrated in vivo target engagement at therapeutically relevant concentrations when orally dosed in mice and prevented body weight loss and improved inflammatory and fibrotic endpoints in a model of Muckle-Wells syndrome (MWS). In two distinct models of neutrophilic airway inflammation, JT002 treatment significantly reduced airway hyperresponsiveness and airway neutrophilia. These results provide a rationale for the therapeutic targeting of the NLRP3 inflammasome in severe asthma and point to the use of JT002 in a variety of inflammatory disorders.

Pharmacology of a Potent and Novel Inhibitor of the NOD-Like Receptor Pyrin Domain-Containing Protein 3 (NLRP3) Inflammasome that Attenuates Development of Nonalcoholic Steatohepatitis and Liver Fibrosis

The NOD-like receptor pyrin domain-containing protein 3 (NLRP3) inflammasome is a multiprotein complex and component of the innate immune system that is activated by exogenous and endogenous danger signals to promote activation of caspase-1 and the maturation and release of the proinflammatory cytokines interleukin (IL)-1β and IL-18. Inappropriate activation of NLRP3 has been implicated in the pathophysiology of multiple inflammatory and autoimmune diseases, including cardiovascular disease, neurodegenerative diseases, and nonalcoholic steatohepatitis (NASH), thus increasing the clinical interest of this target. We describe in this study the preclinical pharmacologic, pharmacokinetic, and pharmacodynamic properties of a novel and highly specific NLRP3 inhibitor, JT001 (6,7-dihydro-5H-pyrazolo[5,1-b][1,3]oxazine-3-sulfonylurea). In cell-based assays, JT001 potently and selectively inhibited NLRP3 inflammasome assembly, resulting in the inhibition of cytokine release and the prevention of pyroptosis, a form of inflammatory cell death triggered by active caspase-1. Oral administration of JT001 to mice inhibited IL-1β production in peritoneal lavage fluid at plasma concentrations that correlated with mouse in vitro whole blood potency. Orally administered JT001 was effective in reducing hepatic inflammation in three different murine models, including the Nlrp3A350V /+CreT model of Muckle-Wells syndrome (MWS), a diet-induced obesity NASH model, and a choline-deficient diet-induced NASH model. Significant reductions in hepatic fibrosis and cell damage were also observed in the MWS and choline-deficient models. Our findings demonstrate that blockade of NLRP3 attenuates hepatic inflammation and fibrosis and support the use of JT001 to investigate the role of NLRP3 in other inflammatory disease models. SIGNIFICANCE STATEMENT: Persistent inflammasome activation is the consequence of inherited mutations of NLRP3 and results in the development of cryopyrin-associated periodic syndromes associated with severe systemic inflammation. NLRP3 is also upregulated in nonalcoholic steatohepatitis, a metabolic chronic liver disease currently missing a cure. Selective and potent inhibitors of NLRP3 hold great promise and have the potential to overcome an urgent unmet need.

Lysyl oxidase like-2 contributes to renal fibrosis in Col4α3/Alport mice

Lysyl oxidase like-2 (LOXL2) is an amine oxidase with both intracellular and extracellular functions. Extracellularly, LOXL2 promotes collagen and elastin crosslinking, whereas intracellularly, LOXL2 has been reported to modify histone H3, stabilize SNAIL, and reduce cell polarity. Although LOXL2 promotes liver and lung fibrosis, little is known regarding its role in renal fibrosis. Here we determine whether LOXL2 influences kidney disease in COL4A3 (-/-) Alport mice. These mice were treated with a small molecule inhibitor selective for LOXL2 or with vehicle and assessed for glomerular sclerosis and fibrosis, albuminuria, blood urea nitrogen, lifespan, pro-fibrotic gene expression and ultrastructure of the glomerular basement membrane. Laminin α2 deposition in the glomerular basement membrane and mesangial filopodial invasion of the glomerular capillaries were also assessed. LOXL2 inhibition significantly reduced interstitial fibrosis and mRNA expression of MMP-2, MMP-9, TGF-β1, and TNF-α. LOXL2 inhibitor treatment also reduced glomerulosclerosis, expression of MMP-10, MMP-12, and MCP-1 mRNA in glomeruli, and decreased albuminuria and blood urea nitrogen. Mesangial filopodial invasion of the capillary tufts was blunted, as was laminin α2 deposition in the glomerular basement membrane, and glomerular basement membrane ultrastructure was normalized. There was no effect on lifespan. Thus, LOXL2 plays an important role in promoting both glomerular and interstitial pathogenesis associated with Alport syndrome in mice. Other etiologies of chronic kidney disease are implicated with our observations.

An Autotaxin/Lysophosphatidic Acid/Interleukin-6 Amplification Loop Drives Scleroderma Fibrosis

OBJECTIVE

We previously implicated the lipid mediator lysophosphatidic acid (LPA) as having a role in dermal fibrosis in systemic sclerosis (SSc). The aim of this study was to identify the role of the LPA-producing enzyme autotaxin (ATX), and to connect the ATX/LPA and interleukin-6 (IL-6) pathways in SSc.

METHODS

We evaluated the effect of a novel ATX inhibitor, PAT-048, on fibrosis and IL-6 expression in the mouse model of bleomycin-induced dermal fibrosis. We used dermal fibroblasts from SSc patients and control subjects to evaluate LPA-induced expression of IL-6, and IL-6-induced expression of ATX. We next evaluated whether LPA-induced ATX expression is dependent on IL-6, and whether baseline IL-6 expression in fibroblasts from SSc patients is dependent on ATX. Finally, we compared ATX and IL-6 expression in the skin of patients with SSc and healthy control subjects.

RESULTS

PAT-048 markedly attenuated bleomycin-induced dermal fibrosis when treatment was initiated before or after the development of fibrosis. LPA stimulated expression of IL-6 in human dermal fibroblasts, and IL-6 stimulated fibroblast expression of ATX, connecting the ATX/LPA and IL-6 pathways in an amplification loop. IL-6 knockdown abrogated LPA-induced ATX expression in fibroblasts, and ATX inhibition attenuated IL-6 expression in fibroblasts and the skin of bleomycin-challenged mice. Expression of both ATX and IL-6 was increased in SSc skin, and LPA-induced IL-6 levels and IL-6-induced ATX levels were increased in fibroblasts from SSc patients compared with controls.

CONCLUSION

ATX is required for the development and maintenance of dermal fibrosis in a mouse model of bleomycin-induced SSc and enables 2 major mediators of SSc fibrogenesis, LPA and IL-6, to amplify the production of each other. Our results suggest that concurrent inhibition of these 2 pathways may be an effective therapeutic strategy for dermal fibrosis in SSc.

Identification of 4-(Aminomethyl)-6-(trifluoromethyl)-2-(phenoxy)pyridine Derivatives as Potent, Selective, and Orally Efficacious Inhibitors of the Copper-Dependent Amine Oxidase, Lysyl Oxidase-Like 2 (LOXL2)

LOXL2 catalyzes the oxidative deamination of ε-amines of lysine and hydroxylysine residues within collagen and elastin, generating reactive aldehydes (allysine). Condensation with other allysines or lysines drives the formation of inter- and intramolecular cross-linkages, a process critical for the remodeling of the ECM. Dysregulation of this process can lead to fibrosis, and LOXL2 is known to be upregulated in fibrotic tissue. Small-molecules that directly inhibit LOXL2 catalytic activity represent a useful option for the treatment of fibrosis. Herein, we describe optimization of an initial hit 2, resulting in identification of racemic-trans-(3-((4-(aminomethyl)-6-(trifluoromethyl)pyridin-2-yl)oxy)phenyl)(3-fluoro-4-hydroxypyrrolidin-1-yl)methanone 28, a potent irreversible inhibitor of LOXL2 that is highly selective over LOX and other amine oxidases. Oral administration of 28 significantly reduced fibrosis in a 14-day mouse lung bleomycin model. The (R,R)-enantiomer 43 (PAT-1251) was selected as the clinical compound which has progressed into healthy volunteer Phase 1 trials, making it the "first-in-class" small-molecule LOXL2 inhibitor to enter clinical development.

Small Molecule Lysyl Oxidase-like 2 (LOXL2) Inhibitors: The Identification of an Inhibitor Selective for LOXL2 over LOX

Two series of novel LOXL2 enzyme inhibitors are described: benzylamines substituted with electron withdrawing groups at the para-position and 2-substituted pyridine-4-ylmethanamines. The most potent compound, (2-chloropyridin-4-yl)methanamine 20 (hLOXL2 IC₅₀ = 126 nM), was shown to be selective for LOXL2 over LOX and three other amine oxidases (MAO-A, MAO-B, and SSAO). Compound 20 is the first published small molecule inhibitor selective for LOXL2 over LOX.

Molecular Liver Cancer Prevention in Cirrhosis by Organ Transcriptome Analysis and Lysophosphatidic Acid Pathway Inhibition

Cirrhosis is a milieu that develops hepatocellular carcinoma (HCC), the second most lethal cancer worldwide. HCC prediction and prevention in cirrhosis are key unmet medical needs. Here we have established an HCC risk gene signature applicable to all major HCC etiologies: hepatitis B/C, alcohol, and non-alcoholic steatohepatitis. A transcriptome meta-analysis of >500 human cirrhotics revealed global regulatory gene modules driving HCC risk and the lysophosphatidic acid pathway as a central chemoprevention target. Pharmacological inhibition of the pathway in vivo reduced tumors and reversed the gene signature, which was verified in organotypic ex vivo culture of patient-derived fibrotic liver tissues. These results demonstrate the utility of clinical organ transcriptome to enable a strategy, namely, reverse-engineering precision cancer prevention.

Autotaxin activity increases locally following lung injury, but is not required for pulmonary lysophosphatidic acid production or fibrosis

Lysophosphatidic acid (LPA) is an important mediator of pulmonary fibrosis. In blood and multiple tumor types, autotaxin produces LPA from lysophosphatidylcholine (LPC) via lysophospholipase D activity, but alternative enzymatic pathways also exist for LPA production. We examined the role of autotaxin (ATX) in pulmonary LPA production during fibrogenesis in a bleomycin mouse model. We found that bleomycin injury increases the bronchoalveolar lavage (BAL) fluid levels of ATX protein 17-fold. However, the LPA and LPC species that increase in BAL of bleomycin-injured mice were discordant, inconsistent with a substrate-product relationship between LPC and LPA in pulmonary fibrosis. LPA species with longer chain polyunsaturated acyl groups predominated in BAL fluid after bleomycin injury, with 22:5 and 22:6 species accounting for 55 and 16% of the total, whereas the predominant BAL LPC species contained shorter chain, saturated acyl groups, with 16:0 and 18:0 species accounting for 56 and 14% of the total. Further, administration of the potent ATX inhibitor PAT-048 to bleomycin-challenged mice markedly decreased ATX activity systemically and in the lung, without effect on pulmonary LPA or fibrosis. Therefore, alternative ATX-independent pathways are likely responsible for local generation of LPA in the injured lung. These pathways will require identification to therapeutically target LPA production in pulmonary fibrosis.-Black, K. E., Berdyshev, E., Bain, G., Castelino, F. V., Shea, B. S., Probst, C. K., Fontaine, B. A., Bronova, I., Goulet, L., Lagares, D., Ahluwalia, N., Knipe, R. S., Natarajan, V., Tager, A. M. Autotaxin activity increases locally following lung injury, but is not required for pulmonary lysophosphatidic acid production or fibrosis.

Structural Basis for Inhibition of Human Autotaxin by Four Potent Compounds with Distinct Modes of Binding

Autotaxin (ATX) is a secreted enzyme that hydrolyzes lysophosphatidylcholine to lysophosphatidic acid (LPA). LPA is a bioactive phospholipid that regulates diverse biological processes, including cell proliferation, migration, and survival/apoptosis, through the activation of a family of G protein-coupled receptors. The ATX-LPA pathway has been implicated in many pathologic conditions, including cancer, fibrosis, inflammation, cholestatic pruritus, and pain. Therefore, ATX inhibitors represent an attractive strategy for the development of therapeutics to treat a variety of diseases. Mouse and rat ATX have been crystallized previously with LPA or small-molecule inhibitors bound. Here, we present the crystal structures of human ATX in complex with four previously unpublished, structurally distinct ATX inhibitors. We demonstrate that the mechanism of inhibition of each compound reflects its unique interactions with human ATX. Our studies may provide a basis for the rational design of novel ATX inhibitors.

Pharmacodynamics, pharmacokinetics and safety of GSK2190915, a novel oral anti-inflammatory 5-lipoxygenase-activating protein inhibitor

AIM

To assess the pharmacokinetics, pharmacodynamics, safety and tolerability of the 5-lipoxygenase-activating protein inhibitor, GSK2190915, after oral dosing in two independent phase I studies, one in Western European and one in Japanese subjects, utilizing different formulations.

METHOD

Western European subjects received single (50-1000 mg) or multiple (10-450 mg) oral doses of GSK2190915 or placebo in a dose-escalating manner. Japanese subjects received three of four GSK2190915 doses (10-200 mg) plus placebo once in a four period crossover design. Blood samples were collected for GSK2190915 concentrations and blood and urine were collected to measure leukotriene B₄ and leukotriene E₄, respectively, as pharmacodynamic markers of drug activity.

RESULTS

There was no clear difference in adverse events between placebo and active drug-treated subjects in either study. Maximum plasma concentrations of GSK2190915 and area under the curve increased in a dose-related manner and mean half-life values ranged from 16-34 h. Dose-dependent inhibition of blood leukotriene B₄ production was observed and near complete inhibition of urinary leukotriene E₄ excretion was shown at all doses except the lowest dose. The EC₅₀ values for inhibition of LTB₄ were 85 nM and 89 nM in the Western European and Japanese studies, respectively.

CONCLUSION

GSK2190915 is well-tolerated with pharmacokinetics and pharmacodynamics in Western European and Japanese subjects that support once daily dosing for 24 h inhibition of leukotrienes. Doses of ≥50 mg show near complete inhibition of urinary leukotriene E₄ at 24 h post-dose, whereas doses of ≥150 mg are required for 24 h inhibition of blood LTB₄.

Abstract 177: Inhibition of the autotaxin-lysophosphatidic acid (ATX-LPA) pathway for chemoprevention of hepatocellular carcinoma

Background: Hepatocellular carcinoma (HCC) is increasing in incidence both in the United States and worldwide. Due to the limited treatment options for HCC, prevention in high-risk patients with cirrhosis has been proposed as an alternative strategy. Aberrant activation of the autotoxin-lysophosphatidic acid (ATX-LPA) pathway, an upstream activator of RhoA signaling, has been associated with fibrosis in several organs. Here, we hypothesized that inhibition of the ATX-LPA pathway in fibrotic liver would reduce progression to cirrhosis and HCC occurrence. Methods: Rats were treated weekly with 50 mg/kg diethylnitrosamine (DEN) to induce sequential development of fibrosis, cirrhosis and HCC. After establishment of liver fibrosis (8 weeks), rats were treated daily by oral gavage with either vehicle control, 5 mg/kg AM063 (an ATX inhibitor) or 30 mg/kg AM095 (a LPA receptor 1 (LPA1) antagonist). At the end of the study, rats were sacrificed, livers were sectioned and stained to analyze disease progression, and tumor nodules were counted. In addition, the effect of LPA on RhoA signaling was investigated in hepatic stellate cell lines (TWNT4 and LX-2). Results: Gene set enrichment analysis revealed that a RhoA activation gene signature, which was associated with poor prognosis in human cirrhosis patients, increased in DEN-injured rat livers. Several members of this gene signature, including pro-fibrogenic connective tissue growth factor (CTGF), were reduced after treatment with either AM063 or AM095. In addition, both AM063 and AM095 significantly (p < 0.01) prevented the development of HCC tumor nodules in DEN-injured livers from a median of 16 in controls to a median of 8 and 6 in AM063 and AM095-treated rats, respectively. Interestingly, the extent of fibrosis in DEN-injured rat livers as measured by Ishak score also significantly (p < 0.01) decreased from a median of 6 in controls to a median of 4 in both AM063 and AM095-treated rats. Examination of hepatic stellate cell lines revealed that LPA increased RhoA-mediated CTGF expression, which was inhibited by AM095. Conclusions: We have identified the ATX-LPA pathway as a major mediator of liver fibrosis progression. Further, AM063 and AM095 are potential chemoprevention strategies for HCC.

Citation Format: Lan Wei, Yujin Hoshida, Gretchen Bain, Jamie Swaney, Gregory Y. Lauwers, Esperance A. Schaefer, Suguru Yamada, Michael Lanuti, Raymond T. Chung, Kenneth K. Tanabe, Bryan C. Fuchs. Inhibition of the autotaxin-lysophosphatidic acid (ATX-LPA) pathway for chemoprevention of hepatocellular carcinoma. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 177. doi:10.1158/1538-7445.AM2013-177

The radiological spectrum of pulmonary lymphoproliferative disease

Pulmonary lymphoproliferative disorders (LPD) are characterised by abnormal proliferation of indigenous cell lines or infiltration of lung parenchyma by lymphoid cells. They encompass a wide spectrum of focal or diffuse abnormalities, which may be classified as reactive or neoplastic on the basis of cellular morphology and clonality. The spectrum of reactive disorders results primarily from antigenic stimulation of bronchial mucosa-associated lymphoid tissue (MALT) and comprises three main entities: follicular bronchiolitis, lymphoid interstitial pneumonia and (more rarely) nodular lymphoid hyperplasia. Primary parenchymal neoplasms are most commonly extranodal marginal zone lymphomas of MALT origin (MALT lymphomas), followed by diffuse large B-cell lymphomas (DLBCLs) and lymphomatoid granulomatosis (LYG). Secondary lymphomatous parenchymal neoplasms (both Hodgkin and non-Hodgkin lymphomas) are far more prevalent than primary neoplasms. Acquired immune deficiency syndrome (AIDS)-related lymphoma (ARL) and post-transplantation lymphoproliferative disorder (PTLD) may also primarily affect the lung parenchyma. Modern advances in treatments for AIDS and transplant medicine are associated with an increase in the incidence of LPD and have heightened the need to understand the range of imaging appearance of these diseases. The multidetector CT (MDCT) findings of LPD are heterogeneous, thereby reflecting the wide spectrum of clinical manifestations of these entities. Understanding the spectrum of LPD and the various imaging manifestations is crucial because the radiologist is often the first one to suggest the diagnosis and has a pivotal role in differentiating these diseases. The current concepts of LPD are discussed together with a demonstration of the breadth of MDCT patterns within this disease spectrum.

Pharmacodynamics, pharmacokinetics, and safety of AM211: a novel and potent antagonist of the prostaglandin D2 receptor type 2

The prostaglandin D(2) receptor type 2 (DP2) and its ligand, PGD(2), have been implicated in the development of asthma and other inflammatory diseases. The authors evaluated the pharmacodynamics, pharmacokinetics and safety of [2'-(3-benzyl-1-ethyl-ureidomethyl)-6-methoxy-4'-trifluoromethyl-biphenyl-3-yl]-acetic acid sodium salt (AM211), a novel and potent DP2 antagonist, in healthy participants. Single and multiple doses of AM211 demonstrated dose-dependent inhibition of eosinophil shape change in blood with near-complete inhibition observed at trough after dosing 200 mg once daily for 7 days. Maximum plasma concentrations and exposures of AM211 increased in a greater-than-dose-proportional manner after single and multiple dosing. After multiple dosing, the exposures on day 7 were higher than on day 1 with accumulation ratio values ranging from 1.4 to 1.5. Mean terminal half-life values ranged from 14 to 25 hours across the dose range of 100 to 600 mg. AM211 was well tolerated at all doses in both the single- and multiple-dose cohorts. These data support additional clinical studies to evaluate AM211 in asthma and other inflammatory diseases.

Amelioration of dermal fibrosis by genetic deletion or pharmacologic antagonism of lysophosphatidic acid receptor 1 in a mouse model of scleroderma

OBJECTIVE

Scleroderma (systemic sclerosis [SSc]), is characterized by progressive multiorgan fibrosis. We recently implicated lysophosphatidic acid (LPA) in the pathogenesis of pulmonary fibrosis. The purpose of the present study was to investigate the roles of LPA and two of its receptors, LPA₁ and LPA₂, in dermal fibrosis in a mouse model of SSc.

METHODS

Wild type (WT), and LPA₁-knockout (KO) and LPA₂-KO mice were injected subcutaneously with bleomycin or phosphate buffered saline (PBS) once daily for 28 days. Dermal thickness, collagen content, and numbers of cells positive for α-smooth muscle actin (α-SMA) or phospho-Smad2 were determined in bleomycin-injected and PBS-injected skin. In separate experiments, a novel selective LPA₁ antagonist AM095 or vehicle alone was administered by oral gavage to C57BL/6 mice that were challenged with 28 daily injections of bleomycin or PBS. AM095 or vehicle treatments were initiated concurrently with, or 7 or 14 days after, the initiation of bleomycin and PBS injections and continued to the end of the experiments. Dermal thickness and collagen content were determined in injected skin.

RESULTS

The LPA₁ -KO mice were markedly resistant to bleomycin-induced increases in dermal thickness and collagen content, whereas the LPA₂-KO mice were as susceptible as the WT mice. Bleomycin-induced increases in dermal α-SMA+ and phospho-Smad2+ cells were abrogated in LPA₁-KO mice. Pharmacologic antagonism of LPA₁ with AM095 significantly attenuated bleomycin-induced dermal fibrosis when administered according to either a preventive regimen or two therapeutic regimens.

CONCLUSION

These results suggest that LPA/LPA₁ pathway inhibition has the potential to be an effective new therapeutic strategy for SSc, and that LPA₁ is an attractive pharmacologic target in dermal fibrosis.

Synthesis of 1,5-diarylpyrazol-3-propanoic acids towards inhibition of cyclooxygenase-1/2 activity and 5-lipoxygenase-mediated LTB4 formation

A set of 25 derivatives of 3-[1-(6-substituted-pyridazin-3-yl)-5-(4-substituted-phenyl)-1H-pyrazol-3-yl]propanoic acids has been synthesized and evaluated for their in vitro cyclooxygenase-1/2 (COX-1/ 2) inhibitory activity using assays with purified COX-1 and COX-2 enzymes as well as for their 5-lipoxygenase (5-LO)-mediated LTB4 formation inhibitory activity using an assay with activated human polymorphonuclear leukocytes (PMNL). Among the synthesized compounds, especially 4g showed COX-1 (IC50 = 1.5 microM) and COX-2 (IC50 = 1.6 microM) inhibitory activity, whereas compounds 4 b and 4 f resulted in the inhibition of 5-LO-mediated LTB4 formation at 14 microM and 12 microM IC50 values, respectively, without any significant inhibition on COX isoforms.

5-lipoxygenase-activating protein inhibitors: development of 3-[3-tert-butylsulfanyl-1-[4-(6-methoxy-pyridin-3-yl)-benzyl]-5-(pyridin-2-ylmethoxy)-1H-indol-2-yl]-2,2-dimethyl-propionic acid (AM103)

The potent and selective 5-lipoxygenase-activating protein leukotriene synthesis inhibitor 3-[3-tert-butylsulfanyl-1-[4-(6-methoxy-pyridin-3-yl)-benzyl]-5-(pyridin-2-ylmethoxy)-1H-indol-2-yl]-2,2-dimethyl-propionic acid (11j) is described. Lead optimization was designed to afford compounds with superior in vitro and in vivo inhibition of leukotriene synthesis in addition to having excellent pharmacokinetics and safety in rats and dogs. The key structural features of these new compounds are incorporation of heterocycles on the indole N-benzyl substituent and replacement of the quinoline group resulting in compounds with excellent in vitro and in vivo activities, superior pharmacokinetics, and improved physical properties. The methoxypyridine derivative 11j has an IC(50) of 4.2 nM in a 5-lipoxygenase-activating protein (FLAP) binding assay, an IC(50) of 349 nM in the human blood LTB(4) inhibition assay, and is efficacious in a murine ovalbumin model of allergen-induced asthma. Compound 11j was selected for clinical development and has successfully completed phase 1 trials in healthy volunteers.

Pharmacological characterization of 3-[3-tert-butylsulfanyl-1-[4-(6-methoxy-pyridin-3-yl)-benzyl]-5-(pyridin-2-ylmethoxy)-1H-indol-2-yl]-2,2-dimethyl-propionic acid (AM103), a novel selective 5-lipoxygenase-activating protein inhibitor that reduces acute and chronic inflammation

Leukotrienes (LTs) are proinflammatory lipid mediators synthesized by the conversion of arachidonic acid (AA) to LTA(4) by the enzyme 5-lipoxygenase (5-LO) in the presence of 5-LO-activating protein (FLAP). 3-[3-tert-Butylsulfanyl-1-[4-(6-methoxy-pyridin-3-yl)-benzyl]-5-(pyridin-2-ylmethoxy)-1H-indol-2-yl]-2,2-dimethyl-propionic acid (AM103) is a novel selective FLAP inhibitor in development for the treatment of respiratory conditions such as asthma. In a rat ex vivo whole-blood calcium ionophore-induced LTB(4) assay, AM103 (administered orally at 1 mg/kg) displayed >50% inhibition for up to 6 h with a calculated EC(50) of approximately 60 nM. When rat lung was challenged in vivo with calcium ionophore, AM103 inhibited LTB(4) and cysteinyl leukotriene (CysLT) production with ED(50) values of 0.8 and 1 mg/kg, respectively. In this model, the EC(50) derived from plasma AM103 was approximately 330 nM for inhibition of both LTB(4) and CysLT. In an acute inflammation setting, AM103 displayed dose-dependent inhibition of LTB(4), CysLT, and plasma protein extravasation induced by peritoneal zymosan injection. In a model of chronic lung inflammation using ovalbumin-primed and challenged BALB/c mice, AM103 reduced the concentrations of eosinophil peroxidase, CysLTs, and interleukin-5 in the bronchoalveolar lavage fluid. Finally, AM103 increased survival time in mice exposed to a lethal intravenous injection of platelet-activating factor. In summary, AM103 is a novel, potent and selective FLAP inhibitor that has excellent pharmacodynamic properties in vivo and is effective in animal models of acute and chronic inflammation and in a model of lethal shock.

The geminal dimethyl analogue of Flurbiprofen as a novel Aβ42 inhibitor and potential Alzheimer’s disease modifying agent

The subtle modification of a selection of Abeta42 inhibiting non-steroidal anti-inflammatory drugs (NSAIDs), through synthesis of the geminal dimethyl analogues, was anticipated to ablate their cyclooxygenase activity whilst maintaining Abeta42 inhibition. Methylflurbiprofen 6 exhibited similar in vitro Abeta42 inhibition to its parent NSAID Flurbiprofen and was further evaluated in the Tg2576 mouse model of Alzheimer's disease and an animal model of gastro-intestinal (GI) impairment, but proved unviable for further clinical development.

DRAK2, a lymphoid-enriched DAP kinase, regulates the TCR activation threshold during thymocyte selection

DAP kinases are a family of serine/threonine kinases known to regulate intrinsic apoptotic processes. DAP-related apoptotic kinase-2 (DRAK2) is highly expressed in lymphoid organs, with differential expression during thymocyte development. Low levels of transcript were observed in CD4/CD8 double-positive (DP) and double-negative populations, whereas single-positive thymocytes possessed elevated levels. Ex vivo stimulation of DP thymocytes with phorbol myristate acetate or antibodies that activate the TCR complex led to the accumulation of DRAK2 in a protein kinase C- and MAP Kinase-dependent fashion. Although DAP kinase family members are thought to potentiate apoptosis, ectopic expression of DRAK2 using retroviral transduction of primary T cells and NIH3T3 fibroblasts failed to decrease rates of survival, suggesting that DRAK2 expression is not sufficient to promote apoptosis. Rather, our results demonstrate that DRAK2 is a primary response gene activated by TCR stimulation in DP thymocytes. Further, we observed that DRAK2 controlled the threshold for calcium signaling in the thymus since positively selected Drak2-deficient thymocytes displayed a reduced requirement for TCR cross-linking. These findings are consistent with a role for DRAK2 in thymocyte selection and lymphoid maturation, and demonstrate that DRAK2 transduces non-apoptotic signals during thymocyte differentiation.

Pharmacological characterization and identification of amino acids involved in the positive modulation of metabotropic glutamate receptor subtype 2

In the present study, we describe the characterization of a positive allosteric modulator at metabotropic glutamate subtype 2 receptors (mGluR2). N-(4-(2-Methoxyphenoxy)-phenyl-N-(2,2,2-trifluoroethylsulfonyl)-pyrid-3-ylmethylamine (LY487379) is a selective positive allosteric modulator at human mGluR2 and is without activity at human mGluR3. Furthermore, LY487379 has no intrinsic agonist or antagonist activity at hmGluR2, as determined by functional guanosine 5'(gamma-[35S]thio)triphosphate ([35S]GTPgammaS) binding, single-cell Ca2+ imaging, and electrophysiological studies. However, LY487379 markedly potentiated glutamate-stimulated [35S]GTPgammaS binding in a concentration-dependent manner at hmGluR2, shifting the glutamate dose-response curve leftward by 3-fold and increasing the maximum levels of [35S]GTPgammaS stimulation. This effect of LY487479 was also observed to a greater extent on the concentration-response curves to selective hmGluR2/3 agonists. In radioligand binding studies to rat cortical membranes, LY487379 increased the affinity of the radiolabeled agonist, [3H]DCG-IV, without affecting the binding affinity of the radiolabeled antagonist, [3H]LY341495. In rat hippocampal slices, coapplication of LY487379 potentiated synaptically evoked mGluR2 responses. Finally, to elucidate the site of action, we systematically exchanged segments and single amino acids between hmGluR2 and hmGluR3. Substitution of Ser688 and/or Gly689 in transmembrane IV along with Asn735 located in transmembrane segment V, with the homologous amino acids of hmGluR3, completely eliminated LY487379 allosteric modulation of hmGluR2. We propose that this allosteric binding site defines a pocket that is different from the orthosteric site located in the amino terminal domain.

IL-7Ralpha and E47: independent pathways required for development of multipotent lymphoid progenitors

Mice that lack the transcription factors encoded by the E2A gene or the receptor for interleukin 7 (IL-7R) have severe overlapping defects in lymphocyte development. Here, we show that E2A proteins are required for the survival of early T-lineage cells; however, they function through a pathway that is distinct from the survival pathway initiated by IL-7R signaling. While E2A proteins are required to suppress caspase 3 activation, ectopic expression of the anti-apoptotic protein Bcl-2 is not sufficient to overcome the lymphopoietic defects observed in the absence of E2A. Remarkably, mice that lack both IL-7Ralpha and E47 display a synergistic decrease in the number of T-cell, NK-cell and multipotent progenitors in the thymus, indicating that these distinct survival pathways converge to promote the development of multipotent lymphoid progenitors.

Early thymocyte development is regulated by modulation of E2A protein activity

The E2A gene encodes the E47 and E12 basic helix-loop-helix (bHLH) transcription factors. T cell development in E2A-deficient mice is partially arrested before lineage commitment. Here we demonstrate that E47 expression becomes uniformly high at the point at which thymocytes begin to commit towards the T cell lineage. E47 protein levels remain high until the double positive developmental stage, at which point they drop to relatively moderate levels, and are further downregulated upon transition to the single positive stage. However, stimuli that mimic pre-T cell receptor (TCR) signaling in committed T cell precursors inhibit E47 DNA-binding activity and induce the bHLH inhibitor Id3 through a mitogen-activated protein kinase kinase-dependent pathway. Consistent with these observations, a deficiency in E2A proteins completely abrogates the developmental block observed in mice with defects in TCR rearrangement. Thus E2A proteins are necessary for both initiating T cell differentiation and inhibiting development in the absence of pre-TCR expression. Mechanistically, these data link pre-TCR mediated signaling and E2A downstream target genes into a common pathway.

The effect of a standard activity on the size of the median nerve as determined by ultrasound visualization

The purpose of this study was to determine whether a standardized hand activity would produce changes in the cross-sectional diameter of the median nerve. Ultrasound measures of proven reliability of the cross-sectional diameter of the median nerve in the wrist were taken. These measures were taken before activity and immediately after the activity, after 5 minutes, and after 10 minutes. The median nerves of 40 normal subjects showed an increase in cross-sectional diameter immediately after hand activity then returned to a size close to the preactivity size within 10 minutes. The cross-sectional area of the carpal canal did not change significantly after the hand activity was performed. Female gender and body mass index over 25 were associated with significantly larger size increases in the median nerve. This preliminary study suggests that ultrasound is sensitive to the effects of activity upon the hand.

Regulation of the helix-loop-helix proteins, E2A and Id3, by the Ras-ERK MAPK cascade

Activation of mitogen-activated protein kinase (MAPK) pathways leads to cellular differentiation and/or proliferation in a wide variety of cell types, including developing thymocytes. The basic helix-loop-helix (bHLH) proteins E12 and E47 and an inhibitor HLH protein, Id3, play key roles in thymocyte differentiation. We show here that E2A DNA binding is lowered in primary immature thymocytes consequent to T cell receptor (TCR)-mediated ligation. Whereas expression of E2A mRNA and protein are unaltered, Id3 transcripts are rapidly induced upon signaling from the TCR. Activation of Id3 transcription is regulated in a dose-dependent manner by the extracellular signal-regulated kinase (ERK) MAPK module. These observations directly connect the ERK MAPK cascade and HLH proteins in a linear pathway.

ES cell neural differentiation reveals a substantial number of novel ESTs

We have used a method for synchronously differentiating murine embryonic stem (ES) cells into functional neurons and glia in culture. Using subtractive hybridization we isolated approximately 1200 cDNA clones from ES cell cultures at the neural precursor stage of neural differentiation. Pilot studies indicated that this library is a good source of novel neuro-embryonic cDNA clones. We therefore screened the entire library by single-pass sequencing. Characterization of 604 non-redundant cDNA clones by BLAST revealed 96 novel expressed sequence tags (ESTs) and an additional 197 matching uncharacterized ESTs or genomic clones derived from genome sequencing projects. With the exception of a handful of genes, whose functions are still unclear, most of the 311 known genes identified in this screen are expressed in embryonic development and/or the nervous system. At least 80 of these genes are implicated in disorders of differentiation, neural development and/or neural function. This study provides an initial snapshot of gene expression during early neural differentiation of ES cell cultures. Given the recent identification of human ES cells, further characterization of these novel and uncharacterized ESTs has the potential to identify genes that may be important in nervous system development, physiology and disease.

The use of ultrasound-guided cutting-needle biopsy in paediatric neck masses

OBJECTIVE

Neck masses are common in children. Although there is a low incidence of therapeutically significant pathology, biopsy is occasionally required for evaluation. Open biopsy or fine needle aspiration may be used to obtain tissue. Open biopsy provides material suitable for histological analysis but requires general anaesthesia. Cytological material obtained by fine needle aspiration is often inconclusive. A core of histological material may also be obtained by percutaneous cutting-needle biopsy, a recognised procedure at other anatomical sites, usually performed under local anaesthesia.

MATERIALS AND METHODS

There are few accounts using cutting needles in adult neck masses and no previous paediatric series. We present our experience of ultrasound-guided core biopsies of neck masses in 15 children ranging in age from three months to 16 years.

RESULTS

Thirteen biopsies were easily performed without sedation as an outpatient procedure under topical and injected local anaesthetic. In all fifteen cases the procedure was well tolerated and a tissue successfully obtained.

CONCLUSION

Ultrasound guided cutting needle biopsies of head and neck masses of children can be performed under local anaesthesia in the majority of cases.

Retro-recombination screening of a mouse embryonic stem cell genomic library

Targeted gene disruption is an important tool in molecular medicine, allowing for the generation of animal models of human disease. Conventional methods of targeting vector (TV) construction are difficult and represent a rate limiting step in any targeting experiment. We previously demonstrated that bacteriophage are capable of acting as TVs directly, obviating the requirement for 'rolling out' plasmids from primary phage clones and thus eliminating an additional, time consuming step. We have also developed methods which facilitate the construction of TVs using recombination. In this approach, modification cassettes and point mutations are shuttled to specific sites in phage TVs using phage-plasmid recombination. Here, we report a further improvement in TV generation using a recombination screening-based approach deemed 'retro-recombination screening' (RRS). We demonstrate that phage vectors containing specific genomic clones can be genetically isolated from a lambdaTK embryonic stem cell genomic library using a cycle of integrative recombination and condensation. By introducing the gam gene of bacteriophage lambda into the probe plasmid it is possible to select for positive clones which have excised the plasmid, thus returning to their native conformation following purification from the library. Rapid clone isolation using the RRS protocol provides another method by which the time required for TV construction may be further reduced.

A systematic review of the clinical diagnostic tests for carpal tunnel syndrome

The purpose of this report was to critically review studies of the clinical diagnostic tests for carpal tunnel syndrome. The reports were located through Medline, Current Contents, related readings, and the reference lists of the articles. They all explored the use of clinical diagnostic tests for carpal tunnel syndrome compared with the results of NCS. Criteria for systematically reviewing the studies were developed, tested for reliability, and applied to the studies. Many studies did not have sufficient detail to allow repetition of the protocol by other researchers. The sensitivities and specificities reported for each can be compared with the quality criteria ratings they each received. The literature supports the use of the wrist flexion and carpal compression test and suggests that 2-point discrimination has low sensitivity for diagnosing carpal tunnel syndrome. Many reports do not include methodology, which makes the results difficult to reproduce and to apply to other populations. (J Hand Surg 2000; 25A:120-127.

Thymocyte maturation is regulated by the activity of the helix-loop-helix protein, E47

The E2A proteins, E12 and E47, are required for progression through multiple developmental pathways, including early B and T lymphopoiesis. Here, we provide in vitro and in vivo evidence demonstrating that E47 activity regulates double-positive thymocyte maturation. In the absence of E47 activity, positive selection of both major histocompatibility complex (MHC) class I- and class II-restricted T cell receptors (TCRs) is perturbed. Additionally, development of CD8 lineage T cells in an MHC class I-restricted TCR transgenic background is sensitive to the dosage of E47. Mice deficient for E47 display an increase in production of mature CD4 and CD8 lineage T cells. Furthermore, ectopic expression of an E2A inhibitor helix-loop-helix protein, Id3, promotes the in vitro differentiation of an immature T cell line. These results demonstrate that E2A functions as a regulator of thymocyte positive selection.

Positive and negative regulation of V(D)J recombination by the E2A proteins

A key feature of B and T lymphocyte development is the generation of antigen receptors through the rearrangement and assembly of the germline variable (V), diversity (D), and joining (J) gene segments. However, the mechanisms responsible for regulating developmentally ordered gene rearrangements are largely unknown. Here we show that the E2A gene products are essential for the proper coordinated temporal regulation of V(D)J rearrangements within the T cell receptor (TCR) gamma and delta loci. Specifically, we show that E2A is required during adult thymocyte development to inhibit rearrangements to the gamma and delta V regions that normally recombine almost exclusively during fetal thymocyte development. The continued rearrangement of the fetal Vgamma3 gene segment in E2A-deficient adult thymocytes correlates with increased levels of Vgamma3 germline transcripts and increased levels of double-stranded DNA breaks at the recombination signal sequence bordering Vgamma3. Additionally, rearrangements to a number of Vgamma and Vdelta gene segments used predominantly during adult development are significantly reduced in E2A-deficient thymocytes. Interestingly, at distinct stages of T lineage development, both the increased and decreased rearrangement of particular Vdelta gene segments is highly sensitive to the dosage of the E2A gene products, suggesting that the concentration of the E2A proteins is rate limiting for the recombination reaction involving these Vdelta regions.

Neural cells derived by in vitro differentiation of P19 and embryonic stem cells

The past decade has seen great progress in understanding the key genes involved in GABAergic transmission. The genes for GAD, multiple subunits of the ionotropic GABA receptors, metabotropic GABA receptors, and GABA uptake proteins have been cloned. Analysis of the cloned genes has yielded a plethora of fundamental insights into the role of the corresponding proteins in mediating GABAergic signals (reviewed in Tobin et al. and Erlander and Tobin). Tools based on these new studies, ranging from monoclonal antibodies to gene probes, have also allowed detailed mapping of expression patterns in the central nervous system (CNS). These new studies reveal that some components of GABAergic transmission have a very wide distribution, being expressed by GABAergic neurons throughout the CNS. Others have a much more restricted pattern of expression. The highly specific expression of GABAergic genes poses a set of fundamental challenges to developmental neurobiology. What genetic mechanisms underlie these patterns of expression? How are complex structures such as receptors assembled? How do the components of a GABAergic synapse come to be localized in proximity to each other so as to make functional transmission possible? Cell lines that express GABAergic phenotypes play an important part in answering these and related questions. With appropriate cell lines it should be possible to manipulate genes related to the GABAergic phenotype in ways that shed light on these questions. Recently, work from several laboratories, including our own, has shown that two pluripotent cell lines from the mouse, the P19 embryonal carcinoma line and embryonic stem (ES) cells, are capable of differentiating into neuron-like cells with GABAergic phenotypes. Since these cell lines are highly suitable for genetic manipulation, they should be extremely useful for studying the relationship between GABA-related genes and the phenotypes they encode.

The role of E-proteins in B- and T-lymphocyte development

Department of lymphocytes from hematopoietic stem cells is controlled, in part, by the activity of transcriptional regulatory proteins. In particular, one class of helix-loop-helix proteins, termed E-proteins, have been implicated in the regulation of gene expression during B-cell development. Recent analysis of gene-targeted mice has allowed a direct assessment of the functional roles of several E-protein family members in hematopoiesis. In this review we describe the defects in B- and T-lymphocyte development in mice carrying targeted mutations in the E-protein genes and discuss our current understanding of the role of these proteins in lymphoid development.

Cleft palate in mice with a targeted mutation in the gamma-aminobutyric acid-producing enzyme glutamic acid decarboxylase 67

The functions of neurotransmitters in fetal development are poorly understood. Genetic observations have suggested a role for the inhibitory amino acid neurotransmitter gamma-aminobutyric acid (GABA) in the normal development of the mouse palate. Mice homozygous for mutations in the beta-3 GABAA receptor subunit develop a cleft secondary palate. GABA, the ligand for this receptor, is synthesized by the enzyme glutamic acid decarboxylase. We have disrupted one of the two mouse Gad genes by gene targeting and also find defects in the formation of the palate. The striking similarity in phenotype between the receptor and ligand mutations clearly demonstrates a role for GABA signaling in normal palate development.