Human mast cell line-1 (HMC-1) cells transfected with FcɛRIα are sensitive to IgE/antigen-mediated stimulation demonstrating selectivity towards cytokine production

Mast cells play important roles in allergic and inflammatory diseases. Efforts to better understand human mast cell activation and develop novel inhibitory agents have been hampered by the lack of suitable human mast cell lines. The HMC-1 mast cell line has been extensively used, but lacks native expression of the human high-affinity IgE receptor FcɛRI limiting its applications.We have stably transfected HMC-1 cells with the IgE- binding alpha-subunit of FcɛRI to generate HMCα cells that are antigen-responsive. We have used flow cytometry, cell signaling assays, pharmacological pathway inhibitors and cell functional assays to characterize the properties of HMCα cells. IgE/antigen responses were compared with those of the adenosine receptor agonist NECA. Surface expression of FcεRI in HMCα cells was demonstrated and was enhanced by prior sensitization with IgE. Activation of HMCα cells with IgE/antigen did not produce degranulation, but did lead to release of numerous cytokines. Whilst there was no measurable increase of intracellular Ca2+ or marked general changes in protein tyrosine phosphorylation, IgE/antigen stimulation of HMCα cells enhanced phosphorylation of p38MAPK and Erk. Inhibitors of these pathways, as well as the src kinase inhibitor PP2, attenuated IgE/antigen-induced cytokine release. In summary, we have generated and characterized HMCα cells and show that they are a useful and relevant human mast cell model to examine FcɛRI stabilization, signaling and mediator release. We envisage that HMCα cells will have utility in understanding the importance of mast cells in human allergic disease and in assessing the activity of novel anti-allergic compounds

Allergy-Specific Phenome-Wide Association Study For Immunogenes In Turkish Children

To dissect the role of immunogenetics in allergy and asthma, we performed a phenome-wide association study in 974 Turkish children selected from a cross-sectional study conducted using ISAAC (International Study of Asthma and Allergies in Children) Phase II tools. We investigated 9 loci involved in different immune functions (ADAM33, ADRB2, CD14, IL13, IL4, IL4R, MS4A2, SERPINE1, and TNF) with respect to 116 traits assessed through blood tests, hypertonic saline challenge tests, questionnaires, and skin prick tests. Multiple associations were observed for ADAM33: rs2280090 was associated with reduced MEF240% (i.e., the ratio of Mean Expiratory Flow after 240s of hypertonic saline inhalation with respect to the age-and ancestry-matched reference value) and with an increased risk of allergic bronchitis (p = 1.77*10(-4) and p = 7.94*10(-4), respectively); rs3918396 was associated with wheezing and eczema comorbidity (p = 3.41*10(-4)). IL4 rs2243250 was associated with increased FEV240 (Forced Expiratory Flow Volume after 240s of hypertonic saline inhalation; p = 4.81*10(-4)) and CD14 rs2569190 was associated with asthma diagnosis (p = 1.36*10(-3)). ADAM33 and IL4 appeared to play a role in the processes linked to allergic airway inflammation and lung function. Due to its association with wheezing and eczema comorbidity, ADAM33 may also be involved in the atopic march.WoSScopu

A Family of non-GPCR Chemosensors Defines an Alternative Logic for Mammalian Olfaction

Odor perception in mammals is mediated by parallel sensory pathways that convey distinct information about the olfactory world. Multiple olfactory subsystems express characteristic seven-transmembrane G-protein coupled receptors (GPCRs) in a one-receptor-per-neuron pattern that facilitates odor discrimination. Sensory neurons of the “necklace” subsystem are nestled within the recesses of the olfactory epithelium and detect diverse odorants; however, they do not express known GPCR odor receptors. Here we report that members of the four-pass transmembrane MS4A protein family are chemosensors expressed within necklace sensory neurons. These receptors localize to sensory endings and confer responses to ethologically-relevant ligands including pheromones and fatty acids in vitro and in vivo. Individual necklace neurons co-express many MS4A proteins and are activated by multiple MS4A ligands; this pooling of information suggests that the necklace is organized more like subsystems for taste than for smell. The MS4As therefore define a distinct mechanism and functional logic for mammalian olfaction