title: Activation of histamine H4 receptor inhibits TNFα/IMD-0354-induced apoptosis in human salivary NS-SV-AC cells.
abstract: Apoptosis is involved in the pathogenesis of Sjögren's syndrome (SS), an autoimmune disease affecting exocrine glands. Our recent studies revealed diminished histamine H4 receptor (H₄R) expression and impaired histamine transport in the salivary gland epithelial cells in SS. The aim was now to test if nanomolar histamine and high-affinity H₄R signaling affect apoptosis of human salivary gland epithelial cell. Simian virus 40-immortalized acinar NS-SV-AC cells were cultured in serum-free keratinocyte medium ± histamine H₄R agonist HST-10. Expression and internalization of H₄R were studied by immunofluorescence staining ± clathrin inhibitor methyl-β-cyclodextrin (MβCD). Apoptosis induced using tumor necrosis factor-α with nuclear factor-κB inhibitor IMD-0354 was studied using phase contrast microscopy, Western blot, flow cytometry and polymerase chain reaction (qRT-PCR). HST-10-stimulated H₄R internalization was inhibited by MβCD. Western blotting revealed diminished phosphorylated c-Jun N-terminal kinase JNK, but unchanged levels of phosphorylated extracellular signal regulated kinase pERK1/2 in H₄R-stimulated samples compared to controls. qRT-PCR showed up-regulated expression of anti-apoptotic B cell lymphoma-extra large/Bcl-xL mRNAs and proteins, whereas pro-apoptotic Bcl-2-associated X protein/BAX remained unchanged in H4R-stimulated samples. H₄R stimulation diminished cleavage of PARP and flow cytometry showed significant dose-dependent inhibitory effect of H₄R stimulation on apoptosis. As far as we know this is the first study showing inhibitory effect of H₄R activation on apoptosis of human salivary gland cells. Diminished H₄R-mediated activation may contribute to loss of immune tolerance in autoimmune diseases and in SS in particular.
authors.affiliation: Department of Medicine, Helsinki University Central Hospital, Helsinki, Finland.
authors.forename: Vasili
authors.initials: V
authors.lastname: Stegajev
authors.forename: Vesa-Petteri
authors.initials: VP
authors.lastname: Kouri
authors.forename: Abdelhakim
authors.initials: A
authors.lastname: Salem
authors.forename: Stanislav
authors.initials: S
authors.lastname: Rozov
authors.forename: Holger
authors.initials: H
authors.lastname: Stark
authors.forename: Dan C E
authors.initials: DC
authors.lastname: Nordström
authors.forename: Yrjö T
authors.initials: YT
authors.lastname: Konttinen
mesh_terms: D061354:Acinar Cells / Q000187:drug effects / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects*; D051017:Apoptosis Regulatory Proteins / Q000378:metabolism; D001549:Benzamides / Q000494:pharmacology*; D002470:Cell Survival / Q000187:drug effects; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D016328:NF-kappa B / Q000037:antagonists & inhibitors*; D043562:Receptors, G-Protein-Coupled / Q000378:metabolism*; D011968:Receptors, Histamine / Q000378:metabolism*; D000074040:Receptors, Histamine H4; D015398:Signal Transduction; D013363:Submandibular Gland / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D051017:Apoptosis Regulatory Proteins; D001549:Benzamides; C418607:HRH4 protein, human; D016328:NF-kappa B; D043562:Receptors, G-Protein-Coupled; D011968:Receptors, Histamine; D000074040:Receptors, Histamine H4; D014409:Tumor Necrosis Factor-alpha; C492919:N-(3,5-bis(trifluoromethyl)phenyl)-5-chloro-2-hydroxybenzamide