title: Transient receptor potential melastatin 2 is required for lipopolysaccharide-induced cytokine production in human monocytes.
abstract: Transient receptor potential melastatin 2 (TRPM2) is a Ca(2+)-permeable nonselective cation channel that is stimulated by oxidative stress and specifically activated by intracellular ADP-ribose. Because TRPM2 is highly expressed in immunocytes, a role of this channel in inflammation processes has been proposed. The aim of the current study was to determine the function of TRPM2 in LPS-induced cytokine production of human monocytes. Incubation of human primary monocytes with LPS resulted in an upregulation of TRPM2 mRNA, protein, and of ADP-ribose-induced membrane currents. By using short hairpin RNA to downregulate TRPM2 expression in THP-1 monocytes, we demonstrate that TRPM2 is required for the LPS-induced production of IL-6, IL-8, IL-10, and TNF-alpha. Application of LPS led to a time-dependent increase in intracellular Ca(2+) concentrations in THP-1 cells that was clearly reduced by downregulation of TRPM2. Omission of extracellular Ca(2+) strongly decreased TNF-alpha production in TRPM2-expressing cells. Thus, TRPM2-mediated Ca(2+) entry is a central mechanism for LPS-induced cytokine production in monocytic cells. The identification of TRPM2 as a major player in this LPS-dependent process makes it a promising tool in modulating monocyte functions.
authors.affiliation: Department of Immunobiology, Institute of Biology II, University of Leipzig, 04277 Leipzig, Germany.
authors.forename: Janine
authors.initials: J
authors.lastname: Wehrhahn
authors.forename: Robert
authors.initials: R
authors.lastname: Kraft
authors.forename: Christian
authors.initials: C
authors.lastname: Harteneck
authors.forename: Sunna
authors.initials: S
authors.lastname: Hauschildt
mesh_terms: D000246:Adenosine Diphosphate Ribose / Q000494:pharmacology; D015153:Blotting, Western; D002118:Calcium / Q000378:metabolism; D002460:Cell Line; D002478:Cells, Cultured; D016207:Cytokines / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D016753:Interleukin-10 / Q000378:metabolism; D015850:Interleukin-6 / Q000378:metabolism; D016209:Interleukin-8 / Q000378:metabolism; D008070:Lipopolysaccharides / Q000494:pharmacology*; D008564:Membrane Potentials / Q000187:drug effects; D009000:Monocytes / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D018408:Patch-Clamp Techniques; D034622:RNA Interference; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D050053:TRPM Cation Channels / Q000235:genetics / Q000378:metabolism*; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D016207:Cytokines; D015850:Interleukin-6; D016209:Interleukin-8; D008070:Lipopolysaccharides; D012333:RNA, Messenger; D050053:TRPM Cation Channels; C121934:TRPM2 protein, human; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D000246:Adenosine Diphosphate Ribose; D002118:Calcium