Signal Transduction and Activator of Transcription (STAT) is Phosphoregulated by Histamine in Human Lymphocytes ex vivo – New Aspects.

NIERICH KAREN; HORR BIANCA; BORCK HANNELORE; WACKES CLAUDIA; DIEL JANINE; MEDINA VANINA; RIEGER SANDRA; DIEL FRIDHELM

Mayo 11-14, 2005, Bled, Eslovenia.

Congreso; European Histamine Research XXXIV Annual Meeting,; 2005

Signal Transduction and Activator of Transcription (STAT) is Phosphoregulated by Histamine in Human Lymphocytes ex vivo – New Aspects Karen Nierich1, Bianca Horr1, Hannelore Borck1, Claudia Wackes1, Janine Diel1, Vanina Medina3, Sandra Rieger2, Friedhelm Diel1 1Institut für Umwelt und Gesundheit (IUG) and University of  Applied Sciences, FB:Oe, Biochemistry, Marquardstrasse 35, D-36039 Fulda,2GSF Neuherberg, München, Germany, 3School of Pharmacy and Biochemistry, University of Buenos Aires, Argentina Histamine is able to modulate the Th1/Th2 lymphocyte balance and allergic reactions are associated with excessive histamine production causing a shift to Th2 cell recruitment. In this study we aim to investigate whether histamine influences downstream signalling events of the histamine receptor (H) induced crosstalk and how it modulates the JAK/STAT pathway. PBMC from 6 atopics (adult, IgE>1000 IU) as well as 6 sex and age matched non-atopics (IgE<100 IU) were stimulated 3 days with PHA, human mast cell line-1 (HMC-1) with PMA respectively. Agents were added 4 hours post-plating. The MTT-assay was used to examine cell proliferation, Western blots for determination of latent and activated(a) STAT1/STAT6. EMSA was performed for binding tests with STAT1 oligoDNA sc-2573 and the mutant oligoDNA sc-2574 (Santa Cruz Inc, California). Histamine inhibited the lymphocyte proliferation, however, rIL-4 and more effectively rIL-13, induced cell proliferation. This effect was significantly enhanced in the non-atopic cells (p<0.001). Using anti-aSTAT6 we found that response to rIL-4 correlated with latent STAT6 expression. Anti-aSTAT6 indicated both histamine and rIL-4 to induce aSTAT6 stimulation in the atopic cells and HMC-1. STAT1 and aSTAT1 were counterparts to STAT6 and cleaved a 28kD-fragment after 3 days. Thioperamide (H3-antagonist) and clobenpropit (H4-agonist) as well as STAT1 DNA binding experiments (EMSA) indicated a crucial role for H4-receptors in signal transduction processes with STAT1 consensus and mutant oligonucleotides. It can be suggested that histamine modulates the IL-4 induced JAK/STAT pathway predominantly in atopic cells and HMC-1 by modulating the H4 receptor induced signal transduction. This may explain the up-regulation of autocrine stimulated Th2 cells in atopic patients.