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Background: PDGFR-inhibition by the tyrosine kinase inhibitor (TKI) nintedanib attenuates the progress of idiopathic pulmonary fibrosis (IPF). However, the effects of PDGF-BB on the airway tone are almost unknown. We studied this issue and the mechanisms beyond, using isolated perfused lungs (IPL) of guinea pigs (GPs) and precision-cut lung slices (PCLS) of GPs and humans.Methods: IPL: PDGF-BB was perfused after or without pre-treatment with the TKI imatinib (perfused/nebulised) and its effects on the tidal volume (TV), the dynamic compliance (Cdyn) and the resistance were studied.Pcls (gp): The bronchoconstrictive effects of PDGF-BB and the mechanisms beyond were evaluated. PCLS (human): The bronchoconstrictive effects of PDGF-BB and the bronchorelaxant effects of imatinib were studied. All changes of the airway tone were measured by videomicroscopy and indicated as changes of the initial airway area.Results: PCLS (GP/human): PDGF-BB lead to a contraction of airways. IPL: PDGF-BB decreased TV and Cdyn, whereas the resistance did not increase significantly. In both models, inhibition of PDGFR-(β) (imatinib/SU6668) prevented the bronchoconstrictive effect of PDGF-BB. The mechanisms beyond PDGF-BB-induced bronchoconstriction include activation of MAP2K and TP-receptors, actin polymerisation and Ca2+-sensitisation, whereas the increase of Ca2+ itself and the activation of EP1-4-receptors were not of relevance. In addition, imatinib relaxed pre-constricted human airways.Conclusions: PDGFR regulates the airway tone. In PCLS from GPs, this regulatory mechanism depends on the β-subunit. Hence, PDGFR-inhibition may not only represent a target to improve chronic airway disease such as IPF, but may also provide acute bronchodilation in asthma. Since asthma therapy uses topical application. This is even more relevant, as nebulisation of imatinib also appears to be effective. [ABSTRACT FROM AUTHOR]

Abstract Background Macrophage migration inhibitory factor (MIF) is a pleiotropic cytokine and mediator of acute and chronic inflammatory diseases. MIF is overexpressed in various tumours and has been suggested as a molecular link between chronic inflammation and cancer. MIF overexpression is observed in breast cancer but its causal role in the development of this tumour entity is unclear. Methods MIF levels in breast cancer cell lines were determined by ELISA and Western blot. CD74 was measured by Western blot, fluorescence microscopy and flow cytometry. Cell proliferation was studied by BrdU incorporation, cell adhesion by Matrigel adhesion assay, and cell invasion by migration assay through Matrigel-coated filters using the Transwell system. MIF expression in primary human breast cancers was measured by tissue microarray and a semi-quantitative immunoreactivity score (IRS) and comparison with histopathological parameters and patient outcome data. Results MIF was abundantly expressed in the non-invasive breast cancer cell lines MDA-MB-468 and ZR-75-1, but not in invasive MDA-MB-231 cells, which in turn expressed higher levels of the MIF-receptor CD74. Stimulation with exogenous MIF led to a dramatic upregulation of MIF secretion (50-fold) in MDA-MB-231 cells. Autocrine MIF promoted tumour cell proliferation, as indicated by blockade of MIF or CD74 in MDA-MB-231 and MDA-MB-468, and MDA-MB-231 invasiveness was enhanced by exogenous MIF. We correlated the expression of MIF with histopathological parameters and patient outcome data, using a tissue microarray of 175 primary invasive breast cancers and 35 normal control tissues. MIF was upregulated in breast cancer versus normal tissue (median IRS = 8 versus 6). MIF expression showed positive correlations with progesterone (p = 0.006) and estrogen (p = 0.028) receptor expression, markers of a favourable prognosis and a negative correlation to tumour size (p = 0.007). In line with these data, disease-specific overall (OS) as well as recurrence-free (RFS) survival was significantly improved in breast cancer patients with abundant cytosolic MIF expression compared to MIF low expressers (5-year OS = 67% versus 50%, p = 0.0019; 5-year RFS = 52% versus 36%, p = 0.0327). Conclusion We conclude that intracellular expression of MIF in breast cancer cells is beneficial, whereas extracellular MIF may play a pro-oncogenic role in promoting breast cancer cell-stroma interactions.

Background: Allergic diseases and especially allergic asthma are widespread diseases with high prevalence in childhood, but also in adults. Acid sphingomyelinase (ASM) is a key regulator of the sphingolipid pathway. Previous studies defined the association of ASM with the pathogenesis of TH1‐directed lung diseases like cystic fibrosis and acute lung injury. Here, we define the role of ASM in TH2‐regulated allergic bronchial asthma. Methods: To determine the role of Asm under baseline conditions, wild‐type (WT) and Asm−/− mice were ventilated with a flexiVent setup and bronchial hyperresponsiveness was determined using acetylcholine. Flow cytometry and cytokine measurements in bronchoalveolar lavage fluid and lung tissue were followed by in vitro TH2 differentiations with cells from WT and Asm−/− mice and blockade of Asm with amitriptyline. As proof of principle, we conducted an ovalbumin‐induced model of asthma in WT‐ and Asm−/− mice. Results: At baseline, Asm−/− mice showed better lung mechanics, but unaltered bronchial hyperresponsiveness. Higher numbers of Asm−/− T cells in bronchoalveolar lavage fluid released lower levels of IL‐4 and IL‐5, and these results were paralleled by decreased production of typical TH2 cytokines in Asm−/− T lymphocytes in vitro. This phenotype could be imitated by incubation of T cells with amitriptyline. In the ovalbumin asthma model, Asm−/− animals were protected from high disease activity and showed better lung functions and lower levels of eosinophils and TH2 cytokines. Conclusion: Asm deficiency could induce higher numbers of TH2 cells in the lung, but those cells release decreased TH2 cytokine levels. Hereby, Asm−/− animals are protected from bronchial asthma, which possibly offers novel therapeutic strategies, for example, with ASM blockade. [ABSTRACT FROM AUTHOR]

Introduction: Levosimendan is approved for left heart failure and is also used in right heart failure to reduce right ventricular afterload. Despite the fact that pulmonary arteries (PAs) and pulmonary veins (PVs) contribute to cardiac load, their responses to levosimendan are largely unknown. Materials and Methods: Levosimendan-induced vasorelaxation of PAs and PVs was studied in precision-cut lung slices from guinea pigs by videomicroscopy; baseline luminal area was defined as 100%. Intracellular cAMP- and cGMP-levels were measured by ELISA and NO end products were determined by the Griess reaction. Results: Levosimendan relaxed control PVs (116%) and those pre-constricted with an endothelinA-receptor agonist (119%). PAs were only relaxed if pre-constricted (115%). Inhibition of KATP-channels (glibenclamide), adenyl cyclase (SQ 22536) and protein kinase G (KT 5823) largely attenuated the levosimendan-induced relaxation in control PVs, as well as in pre-constricted PAs and PVs. Inhibition of BKCa2+-channels (iberiotoxin) and Kv-channels (4-aminopyridine) only contributed to the relaxant effect of levosimendan in pre-constricted PAs. In both PAs and PVs, levosimendan increased intracellular cAMP- and cGMP-levels, whereas NO end products remained unchanged. Notably, basal NO-levels were higher in PVs. The KATP-channel activator levcromakalim relaxed PAs dependent on cAMP/PKA/PKG and increased cAMP-levels in PAs. Discussion: Levosimendan initiates complex and divergent signaling pathways in PAs and PVs. Levosimendan relaxes PAs and PVs primarily via KATP-channels and cAMP/cGMP; in PAs, BKCa2+- and Kv-channels are also involved. Our findings with levcromakalim do further suggest that in PAs the activation of KATP-channels leads to the production of cAMP/PKA/PKG. In conclusion, these results suggest that levosimendan might reduce right ventricular afterload by relaxation of PAs as well as pulmonary hydrostatic pressure and pulmonary edema by relaxation of PVs. [ABSTRACT FROM AUTHOR]

Background: Allergic diseases and especially allergic asthma are widespread diseases with high prevalence in childhood, but also in adults. Acid sphingomyelinase (ASM) is a key regulator of the sphingolipid pathway. Previous studies defined the association of ASM with the pathogenesis of T H 1-directed lung diseases like cystic fibrosis and acute lung injury. Here, we define the role of ASM in T H 2-regulated allergic bronchial asthma., Methods: To determine the role of Asm under baseline conditions, wild-type (WT) and Asm -/- mice were ventilated with a flexiVent setup and bronchial hyperresponsiveness was determined using acetylcholine. Flow cytometry and cytokine measurements in bronchoalveolar lavage fluid and lung tissue were followed by in vitro T H 2 differentiations with cells from WT and Asm -/- mice and blockade of Asm with amitriptyline. As proof of principle, we conducted an ovalbumin-induced model of asthma in WT- and Asm -/-  mice., Results: At baseline, Asm -/- mice showed better lung mechanics, but unaltered bronchial hyperresponsiveness. Higher numbers of Asm -/- T cells in bronchoalveolar lavage fluid released lower levels of IL-4 and IL-5, and these results were paralleled by decreased production of typical T H 2 cytokines in Asm -/- T lymphocytes in vitro. This phenotype could be imitated by incubation of T cells with amitriptyline. In the ovalbumin asthma model, Asm -/- animals were protected from high disease activity and showed better lung functions and lower levels of eosinophils and T H 2 cytokines., Conclusion: Asm deficiency could induce higher numbers of T H 2 cells in the lung, but those cells release decreased T H 2 cytokine levels. Hereby, Asm -/- animals are protected from bronchial asthma, which possibly offers novel therapeutic strategies, for example, with ASM blockade., (© 2020 The Authors. Allergy published by John Wiley & Sons Ltd.)