Extracellular vesicles released by cancer-associated fibroblast-induced myeloid-derived suppressor cells inhibit T-cell function.

Myeloid cells are known to play a crucial role in creating a tumor-promoting and immune suppressive microenvironment. Our previous study demonstrated that primary human monocytes can be polarized into immunosuppressive myeloid-derived suppressor cells (MDSCs) by cancer-associated fibroblasts (CAFs) in a 3D co-culture system. However, the molecular mechanisms underlying the immunosuppressive function of MDSCs, especially CAF-induced MDSCs, remain poorly understood. Using mass spectrometry-based proteomics, we compared cell surface protein changes among monocytes, in vitro differentiated CAF-induced MDSCs, M1/M2 macrophages, and dendritic cells, and identified an extracellular vesicle (EV)-mediated secretory phenotype of MDSCs. Functional assays using an MDSC/T-cell co-culture system revealed that blocking EV generation in CAF-induced MDSCs reversed their ability to suppress T-cell proliferation, while EVs isolated from CAF-induced MDSCs directly inhibited T-cell function. Furthermore, we identified fructose bisphosphatase 1 (FBP1) as a cargo protein that is highly enriched in EVs isolated from CAF-induced MDSCs, and pharmacological inhibition of FBP1 partially reversed the suppressive phenotype of MDSCs. Our findings provide valuable insights into the cell surface proteome of different monocyte-derived myeloid subsets and uncover a novel mechanism underlying the interplay between CAFs and myeloid cells in shaping a tumor-permissive microenvironment.

Circular RNA circ_0073181 contributes to tumorigenesis by regulating protein tyrosine phosphatase receptor type E via miR-548p in hepatocellular carcinoma.

Hepatocellular carcinoma (HCC) is a major world public problem in the world, with high morbidity and mortality rates. Circular RNA (circRNA) circ_0073181 has been reported to be related to HCC development. However, the mechanism of circ_0073181 in HCC is far from being addressed. Circ_0073181, microRNA-548p (miR-548p) and protein tyrosine phosphatase receptor type E (PTPRE) level were detected by real-time quantitative PCR (RT-qPCR). Cell proliferation, migration, invasion and apoptosis were detected by Cell Counting Kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine, wound healing, transwell and flow cytometry assay. Protein levels of proliferating cell nuclear antigen, Bcl-2 related X protein (Bax) and PTPRE were examined by western blot assay. The binding relationship between miR-548p and circ_0073181 or PTPRE was predicted by circular RNA interactome and targetScan and then verified by a dual-luciferase reporter and RNA immunoprecipitation (RIP) assays. The biologic role of circ_0073181 on HCC tumor growth was examined by the xenograft tumor model in vivo. Circ_0073181 and PTPRE were upregulated, and miR-548p was decreased in HCC tissues and cells. Furthermore, circ_0073181 knockdown could boost proliferation, migration, invasion and repress apoptosis of HCC cells in vitro. The mechanical analysis suggested that circ_0073181 could regulate PTPRE expression by sponging miR-548p. In addition, circ_0073181 knockdown suppressed cell growth of HCC in vivo. Circ_0073181 silencing could inhibit HCC cell growth and metastasis partly by regulating the miR-548p/ PTPRE axis, providing a promising therapeutic target for the HCC treatment.

Microstructure Evolution in Cu-Ni-Co-Si-Cr Alloy During Hot Compression by Ce Addition.

Cu-Ni-Si alloys are widely used in lead frames and vacuum devices due to their high electrical conductivity and strength. In this paper, a Cu-Ni-Co-Si-Cr-(Ce) alloy was prepared by vacuum induction melting. Hot compression tests of the Cu-Ni-Co-Si-Cr and Cu-Ni-Co-Si-Cr-Ce alloys were carried out using a Gleeble-1500 simulator at 500-900 °C deformation temperatures and 0.001-10 s-1 strain rates. The texture change was analyzed by electron backscatter diffraction. The <110> fiber component dominated the texture after compression, and the texture intensity was reduced during recrystallization. Moreover, the average misorientation angle φ for Cu-Ni-Co-Si-Cr-Ce (11°) was lower than that of Cu-Ni-Co-Si-Cr (16°) under the same conditions. Processing maps were developed to determine the optimal processing window. The microstructure and precipitates of the Cu-Ni-Co-Si-Cr and Cu-Ni-Co-Si-Cr-Ce alloys were also analyzed. The average grain size of the Cu-Ni-Co-Si-Cr-Ce alloy (48 µm) was finer than that of the Cu-Ni-Co-Si-Cr alloy (80 µm). The average size of precipitates in the Cu-Ni-Co-Si-Cr alloy was 73 nm, while that of the Cu-Ni-Co-Si-Cr-Ce alloy was 27 nm. The addition of Ce delayed the occurrence of dynamic recrystallization.

Cancer-Associated Fibroblasts Promote Immunosuppression by Inducing ROS-Generating Monocytic MDSCs in Lung Squamous Cell Carcinoma.

Cancer-associated fibroblasts (CAF) represent a functionally heterogeneous population of activated fibroblasts that constitutes a major component of tumor stroma. Although CAFs have been shown to promote tumor growth and mediate resistance to chemotherapy, the mechanisms by which they may contribute to immune suppression within the tumor microenvironment (TME) in lung squamous cell carcinoma (LSCC) remain largely unexplored. Here, we identified a positive correlation between CAF and monocytic myeloid cell abundances in 501 primary LSCCs by mining The Cancer Genome Atlas data sets. We further validated this finding in an independent cohort using imaging mass cytometry and found a significant spatial interaction between CAFs and monocytic myeloid cells in the TME. To delineate the interplay between CAFs and monocytic myeloid cells, we used chemotaxis assays to show that LSCC patient-derived CAFs promoted recruitment of CCR2+ monocytes via CCL2, which could be reversed by CCR2 inhibition. Using a three-dimensional culture system, we found that CAFs polarized monocytes to adopt a myeloid-derived suppressor cell (MDSC) phenotype, characterized by robust suppression of autologous CD8+ T-cell proliferation and IFNγ production. We further demonstrated that inhibiting IDO1 and NADPH oxidases, NOX2 and NOX4, restored CD8+ T-cell proliferation by reducing reactive oxygen species (ROS) generation in CAF-induced MDSCs. Taken together, our study highlights a pivotal role of CAFs in regulating monocyte recruitment and differentiation and demonstrated that CCR2 inhibition and ROS scavenging abrogate the CAF-MDSC axis, illuminating a potential therapeutic path to reversing the CAF-mediated immunosuppressive microenvironment.

Circular Complex-Valued GMDH-Type Neural Network for Real-Valued Classification Problems.

Recently, applications of complex-valued neural networks (CVNNs) to real-valued classification problems have attracted significant attention. However, most existing CVNNs are black-box models with poor explanation performance. This study extends the real-valued group method of data handling (RGMDH)-type neural network to the complex field and constructs a circular complex-valued group method of data handling (C-CGMDH)-type neural network, which is a white-box model. First, a complex least squares method is proposed for parameter estimation. Second, a new complex-valued symmetric regularity criterion is constructed with a logarithmic function to represent explicitly the magnitude and phase of the actual and predicted complex output to evaluate and select the middle candidate models. Furthermore, the property of this new complex-valued external criterion is proven to be similar to that of the real external criterion. Before training this model, a circular transformation is used to transform the real-valued input features to the complex field. Twenty-five real-valued classification data sets from the UCI Machine Learning Repository are used to conduct the experiments. The results show that both RGMDH and C-CGMDH models can select the most important features from the complete feature space through a self-organizing modeling process. Compared with RGMDH, the C-CGMDH model converges faster and selects fewer features. Furthermore, its classification performance is statistically significantly better than the benchmark complex-valued and real-valued models. Regarding time complexity, the C-CGMDH model is comparable with other models in dealing with the data sets that have few features. Finally, we demonstrate that the GMDH-type neural network can be interpretable.

Enhanced photothermal conversion properties of magnetic nanofluids through rotating magnetic field for direct absorption solar collector.

The direct absorption solar collector (DASCs) with nanofluids can remarkably improve the utilization efficiency of solar energy. However, in the actual applications, the temperature distribution of the receiver is extremely uneven when the concentration of nanofluids is high or the receiver is deep. This makes the temperature of upper layer much higher than that of the lower layer, resulting in much heat loss to the surrounding by convection. Here, we propose a magnetic forced convection nanofluids absorption system, where an external rotating magnetic field is used to change the heat transfer mechanism of working fluids from traditional heat conduction to the thermal convection. It is found that the photothermal conversion efficiency of FeNi/C-EG nanofluids is up to 58.1% in this system, which is 22.7% higher than non-external rotating magnetic field when the nanofluids concentration is 50 ppm. Furthermore, the agglomeration of nanofluids can be effectively reduced by an external rotating magnetic field.

Enhancing the Vickers hardness, melting point and thermodynamic properties of hafnium dodecaboride.

Although HfB12 is a promising surperhard material because of the boron cuboctahedron cage, the Vickers hardness of HfB12 remains controversial. We apply first-principles calculations to investigate the influence of a transition metal on the structural stability, Vickers hardness and thermodynamic properties of HfB12. The Vickers hardness of HfB12 is 39.3 GPa. In particular, the Vickers hardness of TM-doped HfB12, which are novel superhard materials, is larger than 40 GPa. The Vickers hardness of Re-doped HfB12 is up to 47.6 GPa. The improvement of Vickers hardness is that the introduction of an alloying element improves the localized hybridization between B and Hf, and then enhances the bond strength of the B-B covalent bond and the Hf-B bond. In addition, these alloying elements enhance the melting-point and Debye temperature of the HfB12. Therefore, we believe that alloying is an effective method to improve the Vickers hardness and thermodynamic properties of HfB12 superhard material.

Unique Cu@CuPt Core-Shell Concave Octahedron with Enhanced Methanol Oxidation Activity.

Although tremendous efforts have been devoted to the exploration of cost-effective, active, and stable electrochemical catalysts, only few significant breakthroughs have been achieved up to now. Therefore, exploring new catalysts and improving catalyst activity and stability are still major tasks at present. Controllable synthesis of Pt-based alloy nanocrystals with a uniform high-index surface and unique architecture has been regarded as an effective strategy to optimize their catalytic efficiency toward electrochemical reactions. Accordingly, here we present a one-pot facile solvothermal process to synthesize novel unique Cu@CuPt core-shell concave octahedron nanocrystals that exhibit both outstanding activity and long durability. By regulating temperatures during the synthesis process, we were able to control the reduction rate of Cu and Pt ions, which could subsequently lead to the sequential stacking of Cu and Pt atoms. Owing to the concave structure, the as-prepared core-shell nanoparticles hold a high-index surface of {312} and {413}. Such surfaces can provide a high density of atomic steps and terraces, which is suggested to be favorable for electrochemical catalysts. Specifically, the Cu@CuPt core-shell concave octahedron presents 8.6/13.1 times enhanced specific/mass activities toward the methanol oxidation reaction in comparison to those of a commercial Pt/C catalyst, respectively. Meanwhile, the as-prepared catalyst exhibits superior durability and antiaggregation properties under harsh electrochemical conditions. The facile method used here proposes a novel idea to the fabrication of nanocrystals with desired compositional distribution, and the as-prepared product offers exciting opportunities to be applied in direct methanol fuel cells.

Inhibition of spleen tyrosine kinase attenuates IgE-mediated airway contraction and mediator release in human precision cut lung slices.

BACKGROUND AND PURPOSE: Asthma presents as a heterogeneous syndrome characterized by airway obstruction, inflammation and hyper-reactivity (AHR). Spleen tyrosine kinase (Syk) mediates allergen-induced mast cell degranulation, a central component of allergen-induced inflammation and AHR. However, the role of Syk in IgE-mediated constriction of human small airways remains unknown. In this study, we addressed whether selective inhibition of Syk attenuates IgE-mediated constriction and mast cell mediator release in human small airways. EXPERIMENTAL APPROACH: Human precision cut lung slices (hPCLS) ex vivo derived from non-asthmatic donors were incubated overnight with human IgE, dexamethasone, montelukast, antihistamines or a selective Syk inhibitor (SYKi). High-affinity IgE receptor (FcεRI) activation by anti-IgE cross-linking was performed, and constriction and mediator release measured. Airway constriction was normalized to that induced by maximal carbachol stimulation. Syk expression (determined by qPCR and immunoblot) was also evaluated in human primary airway smooth muscle (HASM) cells to determine whether Syk directly modulates HASM function. KEY RESULTS: While dexamethasone had little effect on FcεR-mediated contraction, montelukast or antihistamines partially attenuated the response. SYKi abolished anti-IgE-mediated contraction and suppressed the release of mast cell or basophil mediators from the IgE-treated hPCLS. In contrast, SYKi had little effect on the non-allergic contraction induced by carbachol. Syk mRNA and protein were undetectable in HASM cells. CONCLUSIONS AND IMPLICATIONS: A selective Syk inhibitor, but not corticosteroids, abolished FcεR-mediated contraction in human small airways ex vivo. The mechanism involved FcεRI receptor activation on mast cells or basophils that degranulate causing airway constriction, rather than direct actions on HASM.

Potential sites of CFTR activation by tyrosine kinases.

The CFTR chloride channel is tightly regulated by phosphorylation at multiple serine residues. Recently it has been proposed that its activity is also regulated by tyrosine kinases, however the tyrosine phosphorylation sites remain to be identified. In this study we examined 2 candidate tyrosine residues near the boundary between the first nucleotide binding domain and the R domain, a region which is important for channel function but devoid of PKA consensus sequences. Mutating tyrosines at positions 625 and 627 dramatically reduced responses to Src or Pyk2 without altering the activation by PKA, suggesting they may contribute to CFTR regulation.

Regulation of the cystic fibrosis transmembrane conductance regulator anion channel by tyrosine phosphorylation.

The cystic fibrosis transmembrane conductance regulator (CFTR) channel is activated by PKA phosphorylation of a regulatory domain that interacts dynamically with multiple CFTR domains and with other proteins. The large number of consensus sequences for phosphorylation by PKA has naturally focused most attention on regulation by this kinase. We report here that human CFTR is also phosphorylated by the tyrosine kinases p60c-Src (proto-oncogene tyrosine-protein kinase) and the proline-rich tyrosine kinase 2 (Pyk2), and they can also cause robust activation of quiescent CFTR channels. In excised patch-clamp experiments, CFTR activity during exposure to Src or Pyk2 reached ∼80% of that stimulated by PKA. Exposure to PKA after Src or Pyk2 caused a further increase to the level induced by PKA alone, implying a common limiting step. Channels became spontaneously active when v-Src or the catalytic domain of Pyk2 was coexpressed with CFTR and were further stimulated by the tyrosine phosphatase inhibitor dephostatin. Exogenous Src also activated 15SA-CFTR, a variant that lacks 15 potential PKA sites and has little response to PKA. PKA-independent activation by tyrosine phosphorylation has implications for the mechanism of regulation by the R domain and for the physiologic functions of CFTR.

Treatment of acute lung injury by targeting MG53-mediated cell membrane repair.

Injury to lung epithelial cells has a role in multiple lung diseases. We previously identified mitsugumin 53 (MG53) as a component of the cell membrane repair machinery in striated muscle cells. Here we show that MG53 also has a physiological role in the lung and may be used as a treatment in animal models of acute lung injury. Mice lacking MG53 show increased susceptibility to ischaemia-reperfusion and overventilation-induced injury to the lung when compared with wild-type mice. Extracellular application of recombinant human MG53 (rhMG53) protein protects cultured lung epithelial cells against anoxia/reoxygenation-induced injuries. Intravenous delivery or inhalation of rhMG53 reduces symptoms in rodent models of acute lung injury and emphysema. Repetitive administration of rhMG53 improves pulmonary structure associated with chronic lung injury in mice. Our data indicate a physiological function for MG53 in the lung and suggest that targeting membrane repair may be an effective means for treatment or prevention of lung diseases.

Pharmacological evaluation of selective α2c-adrenergic agonists in experimental animal models of nasal congestion.

Nasal congestion is one of the most troublesome symptoms of many upper airways diseases. We characterized the effect of selective α2c-adrenergic agonists in animal models of nasal congestion. In porcine mucosa tissue, compound A and compound B contracted nasal veins with only modest effects on arteries. In in vivo experiments, we examined the nasal decongestant dose-response characteristics, pharmacokinetic/pharmacodynamic relationship, duration of action, potential development of tolerance, and topical efficacy of α2c-adrenergic agonists. Acoustic rhinometry was used to determine nasal cavity dimensions following intranasal compound 48/80 (1%, 75 µl). In feline experiments, compound 48/80 decreased nasal cavity volume and minimum cross-sectional areas by 77% and 40%, respectively. Oral administration of compound A (0.1-3.0 mg/kg), compound B (0.3-5.0 mg/kg), and d-pseudoephedrine (0.3 and 1.0 mg/kg) produced dose-dependent decongestion. Unlike d-pseudoephedrine, compounds A and B did not alter systolic blood pressure. The plasma exposure of compound A to produce a robust decongestion (EC(80)) was 500 nM, which related well to the duration of action of approximately 4.0 hours. No tolerance to the decongestant effect of compound A (1.0 mg/kg p.o.) was observed. To study the topical efficacies of compounds A and B, the drugs were given topically 30 minutes after compound 48/80 (a therapeutic paradigm) where both agents reversed nasal congestion. Finally, nasal-decongestive activity was confirmed in the dog. We demonstrate that α2c-adrenergic agonists behave as nasal decongestants without cardiovascular actions in animal models of upper airway congestion.

Mineralocorticoid receptor antagonists attenuate pulmonary inflammation and bleomycin-evoked fibrosis in rodent models.

Accumulating evidence indicates protective actions of mineralocorticoid antagonists (MR antagonists) on cardiovascular pathology, which includes blunting vascular inflammation and myocardial fibrosis. We examined the anti-inflammatory and anti-fibrotic potential of MR antagonists in rodent respiratory models. In an ovalbumin allergic and challenged Brown Norway rat model, the total cell count in nasal lavage was 29,348 ± 5451, which was blocked by spironolactone (0.3-60 mg/kg, p.o.) and eplerenone (0.3-30 mg/kg, p.o.). We also found that MR antagonists attenuated pulmonary inflammation in the Brown Norway rat. A series of experiments were conducted to determine the actions of MR blockade in acute/chronic lung injury models. (1) Ex vivo lung slice rat experiments found that eplerenone (0.01 and 10 µM) and spironolactone (10 µM) diminished lung hydroxyproline concentrations by 55 ± 5, 122 ± 9, and 83 ± 8%. (2) In in vivo studies, MR antagonists attenuated the increases in bronchioalveolar lavage (BAL) neutrophils and macrophages caused by lung bleomycin exposure. In separate studies, bleomycin (4.0 U/kg, i.t.) increased lung levels of hydroxyproline by approximately 155%, which was blocked by spironolactone (10-60 mg/kg, p.o.). In a rat Lipopolysaccharide (LPS) model, spironolactone inhibited acute increases in BAL cytokines with moderate effects on neutrophils. Finally, we found that chronic LPS exposure significantly increased end expiratory lung and decreased lung elastance in the mouse. These functional effects of chronic LPS were improved by MR antagonists. Our results demonstrate that MR antagonists have significant pharmacological actions in the respiratory system.

Inhibition of spleen tyrosine kinase attenuates allergen-mediated airway constriction.

Spleen tyrosine kinase (SYK) is a key activator of signaling pathways downstream of multiple surface receptors implicated in asthma. SYK function has been extensively studied in mast cells downstream of the high-affinity IgE receptor, FcεR1. Preclinical studies have demonstrated a role for SYK in models of allergic inflammation, but a role in airway constriction has not been demonstrated. Here, we have used a potent and selective pharmacological inhibitor of SYK to determine the role of SYK in allergen-mediated inflammation and airway constriction in preclinical models. Attenuation of allergic airway responses was evaluated in a rat passive anaphylaxis model and rat and sheep inhaled allergen challenge models, as well as an ex vivo model of allergen-mediated airway constriction in rats and cynomolgus monkeys. Pharmacological inhibition of SYK dose-dependently blocked IgE-mediated tracheal plasma extravasation in rats. In a rat ovalbumin-sensitized airway challenge model, oral dosing with an SYK inhibitor led to a dose-dependent reduction in lung inflammatory cells. Ex vivo analysis of allergen-induced airway constriction in ovalbumin-sensitized brown Norway rats showed a complete attenuation with treatment of a SYK inhibitor, as well as a complete block of allergen-induced serotonin release. Similarly, allergen-mediated airway constriction was attenuated in ex vivo studies from nonhuman primate lungs. Intravenous administration of an SYK inhibitor attenuated both early- and late-phase allergen-induced increases in airway resistance in an Ascaris-sensitive sheep allergen challenge model. These data support a key role for SYK signaling in mediating allergic airway responses.

Steroidal C-21 heteroaryl thioethers. Part 3: pregn-4-eno-[3,2-c]pyrazole fused A ring modified steroids as selective glucocorticoid receptor modulators (dissociated steroids).

The introduction of A ring pyrazole modification to the hydrocortisone C-21 heteroaryl thioethers generated compounds with excellent transrepression potency (IL-8 inhibition) compared to their hydrocortisone analogs. However, the transcriptional transactivation activity of these compounds were considerably higher than the corresponding hydrocortisone analogs. Among all the compounds evaluated, a quinoxaline thioether modification demonstrated the best overall in vitro separation.

Steroidal C-21 heteroaryl thioethers (Part 2): discovery of orally bioavailable selective glucocorticoid receptor modulators (dissociated steroids).

The prednisolone C-21 heteroaryl thioethers have been synthesized and evaluated in cell based transrepression and transactivation assays. Most of the compounds demonstrated weak transactivational activity in both human and rat tyrosineaminotransferase functional assay while keeping potent anti-inflammatory activity. The benzimidazole thioether 7 exhibited comparable anti-inflammatory activity and improved safety profile compared to the classical oral steroid prednisolone.

Pharmacological characterization of a novel α2C-adrenoceptor agonist N-[3,4-dihydro-4-(1H-imidazol-4-ylmethyl)-2H-1, 4-benzoxazin-6-yl]-N-ethyl-N'-methylurea (compound A).

We define the pharmacological and pharmacokinetic profiles of a novel α(2C)-adrenoceptor agonist, compound A [N-[3,4-dihydro-4-(1H-imidazol-4-ylmethyl)-2H-1,4-benzoxazin-6-yl]-N-ethyl-N'-methylurea]. This compound has high affinity (K(i)) for the human α(2C)-adrenoceptor (K(i) = 12 nM), and 190- to 260-fold selectivity over the α(2A)- and α(2B)-adrenoceptor subtypes. In cell-based functional assays, compound A produced good agonist (EC(50) = 166 nM) and efficacy (E(max) = 64%) responses at the α(2C)-adrenoceptor, much lower potency and efficacy at the α(2A)-adrenoceptor (EC(50) = 1525 nM; E(max) = 8%) and α(2B)-adrenoceptor (EC(50) = 5814 nM; E(max) = 21%) subtypes, and low or no affinity and functional activity at the α(1A)-, α(1B)-, and α(1D)-adrenoceptor subtypes. In the human saphenous vein postjunctional α(2C)-adrenoceptor bioassay, compound A functions as a potent agonist (pD(2) = 6.3). In a real-time contraction bioassay of pig nasal mucosa, compound A preferentially constricted the veins (EC(50) = 108 nM), and the magnitude of arteriolar contraction reached only 50% of the maximum venular responses. Compound A exhibited no effect on locomotor activity, sedation, and body temperature in mice (up to 100 mg/kg) and did not cause hypertension and mydriasis (30 mg/kg) in conscious rats. Compound A is orally bioavailable (24%) with good plasma exposure. This compound is a substrate for the efflux P-glycoprotein transporter, resulting in very low central nervous system (CNS) penetration. In summary, compound A is a highly selective, orally active, and non-CNS-penetrating α(2C)-adrenoceptor agonist with desirable in vitro and in vivo pharmacological properties suitable for the treatment of nasal congestion.

Concomitant activity of histamine and cysteinyl leukotrienes on porcine nasal mucosal vessels and nasal inflammation in the rat.

BACKGROUND: Histamine and cysteinyl leukotrienes are pivotal mast cell mediators which contribute considerably and likely complementary to the symptoms of allergic rhinitis. Currently, we sought to explore the direct actions of histamine and leukotriene D(4) (LTD(4)), a cysteinyl leukotriene, on porcine nasal arteries and veins. We also studied combined blocks of histamine and cysteinyl leukotrienes using loratadine and montelukast in an in vivo model of allergy-mediated nasal inflammation. METHODS: For the evaluation of the action of histamine and LTD(4) on arteries and veins, porcine nasal mucosa was isolated and cut into slices (100-300 microm thick). Real-time images of the nasal arteries and veins were recorded and vessel activities estimated by changes in cross-sectional area before and after the tested drugs. For the in vivo studies, the effect of loratadine and montelukast given alone and in combination was examined on upper airway inflammation in ovalbumin-sensitized and -challenged Brown Norway rats. RESULTS: Both histamine (0.001-10 micromol/l) and LTD(4) (0.001-10 micromol/l) produced a concentration-dependent increase in the lumen area of nasal mucosa arteries and veins. Histamine (0.01 micromol/l) alone produced a 24 and 12% increase in cross-sectional areas of arteries and veins, respectively. LTD(4) (0.001 micromol/l) alone increased artery and vein dilation by about 17 and 9%, respectively. Combination treatment with histamine (0.01 micromol/l) and LTD(4) (0.001 micromol/l) increased vessel dilation by 65% (arteries) and 26% (veins). In our in vivo Brown Norway rat studies, oral loratadine (0.01-10 mg/kg) and montelukast (0.01-10 mg/kg) significantly reduced antigen-induced total nasal inflammatory cell infiltration in a dose-dependent manner. The antiinflammatory dose-response curve of loratadine was shifted to the left when studied in combination with montelukast (0.01 mg/kg). Similarly, the dose-response characteristics of montelukast (0.01-10 mg/kg) was shifted in the presence of loratadine (0.01 mg/kg). CONCLUSION: Our studies support the position that histamine and cysteinyl leukotrienes may act collaboratively to elicit allergic nasal pathologies such as upper airway inflammation and nasal vessel dilation (which may translate into increased nasal mucosal engorgement). Furthermore, the current results are supportive of the hypothesis that combined treatment of allergic rhinitis with an H(1) receptor antagonist and a CysLT(1) receptor antagonist may have greater benefit than sole treatment with these agents alone.

Pharmacological profile of the NOP agonist and cough suppressing agent SCH 486757 (8-[Bis(2-Chlorophenyl)Methyl]-3-(2-Pyrimidinyl)-8-Azabicyclo[3.2.1]Octan-3-Ol) in preclinical models.

We describe the pharmacological and pharmacokinetic profiles of SCH 486757, a nociceptin/orphanin FQ peptide (NOP) receptor agonist that has recently entered human clinical trials for cough. SCH 486757 selectively binds human NOP receptor (K(i)=4.6+/-0.61nM) over classical opioid receptors. In a guinea pig capsaicin cough model, SCH 486757 (0.01-1mg/kg) suppressed cough at 2, 4, and 6h post oral administration with a maximum efficacy occurring at 4h equivalent to codeine, hydrocodone, dextromethorphan and baclofen. The antitussive effects of SCH 486757 (3.0mg/kg, p.o.) was blocked by the NOP receptor antagonist J113397 (12mg/kg, i.p.) but not by naltrexone (10mg/kg, p.o.). SCH 486757 does not produce tolerance to its antitussive activity after a 5-day BID dosing regimen. After acute and chronic dosing paradigms, SCH 486757 (1mg/kg) inhibited capsaicin-evoked coughing by 46+/-9% and 40+/-11%, respectively. In a feline mechanically-evoked cough model, SCH 486757 produces a maximum inhibition of cough and expiratory abdominal electromyogram amplitude of 59 and 61%, respectively. SCH 486757 did not significantly affect inspiratory electromyogram amplitude. We examined the abuse potential of SCH 486757 (10mg/kg, p.o.) in a rat conditioned place preference procedure which is sensitive to classical drugs of abuse, such as amphetamine and morphine. SCH 486757 was without effect in this model. Finally, SCH 486757 displays a good oral pharmacokinetic profile in the guinea pig, rat and dog. We conclude that SCH 486757 has a favorable antitussive profile in preclinical animal models.