title: Inhibition of the IgE-mediated activation of RBL-2H3 cells by TIPP, a novel thymic immunosuppressive pentapeptide.
abstract: TIPP is a novel thymic immunosuppressive pentapeptide originally obtained from calf thymic immunosuppressive extract. The present study aimed to investigate the inhibitory activity of TIPP on IgE-mediated activation of RBL-2H3 cells. Release of β-hexosaminidase and histamine, intracellular calcium, membrane ruffling, mRNA levels of cytokines, cyclooxygenase-2 (COX-2) expression, and activation of mitogen-activated protein kinases (MAP kinases) and NF-κB were determined by colorimetric assay, fluorescence spectrophotometer, confocal fluorescence microscope, quantification PCR, and Western blot, respectively. The results showed that TIPP significantly inhibited the degranulation in IgE-antigen complex-stimulated RBL-2H3 cells without cytotoxicity. TIPP significantly suppressed the increase of intracellular calcium and the rearrangement of F-actin, attenuated the transcription of pro-inflammatory cytokines (IL-3, -4, -6, -13, TNF-α, and monocyte chemotactic protein-1 (MCP-1)), and decreased the expression of COX-2. Western blot analysis showed that TIPP had an inhibitory activity on the phosphorylation of extracellular signal-regulated protein kinase 1/2 (ERK1/2) and ERK kinase 1/2 (MEK1/2), and inhibited the activation of NF-κB. The data suggested that TIPP effectively suppressed IgE-mediated activation of RBL-2H3 cells via blocking MEK/ERK and NF-κB signaling pathways.
authors.affiliation: Key Laboratory of Chemical Biology of Natural Products (Ministry of Education), Institute of Biochemical and Biotechnological Drugs, School of Pharmaceutical Sciences, Shandong University, Jinan 250012, China. xhrg_1042@126.com.
authors.forename: Qianqian
authors.initials: Q
authors.lastname: Lian
authors.affiliation: Department of Pharmacology, School of Pharmaceutical Sciences, Shandong University, Jinan 250012, China. chengyn@sdu.edu.cn.
authors.forename: Yanna
authors.initials: Y
authors.lastname: Cheng
authors.affiliation: Key Laboratory of Chemical Biology of Natural Products (Ministry of Education), Institute of Biochemical and Biotechnological Drugs, School of Pharmaceutical Sciences, Shandong University, Jinan 250012, China. zhongchq@163.com.
authors.forename: Chuanqing
authors.initials: C
authors.lastname: Zhong
authors.affiliation: Key Laboratory of Chemical Biology of Natural Products (Ministry of Education), Institute of Biochemical and Biotechnological Drugs, School of Pharmaceutical Sciences, Shandong University, Jinan 250012, China. fswang@sdu.edu.cn.
authors.forename: Fengshan
authors.initials: F
authors.lastname: Wang
mesh_terms: D000818:Animals; D000936:Antigen-Antibody Complex / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D016923:Cell Death / Q000187:drug effects; D015550:Cell Degranulation / Q000187:drug effects; D002460:Cell Line; D021961:Cell Membrane Structures / Q000187:drug effects / Q000378:metabolism; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism; D051546:Cyclooxygenase 2 / Q000378:metabolism; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D006632:Histamine / Q000378:metabolism; D007073:Immunoglobulin E / Q000378:metabolism*; D007166:Immunosuppressive Agents / Q000494:pharmacology*; D018836:Inflammation Mediators / Q000378:metabolism; D008407:Mast Cells / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D009842:Oligopeptides / Q000737:chemistry / Q000494:pharmacology*; D021381:Protein Transport / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D044005:Tetrahydroisoquinolines / Q000737:chemistry / Q000494:pharmacology*; D013950:Thymus Gland / Q000187:drug effects / Q000276:immunology*; D001619:beta-N-Acetylhexosaminidases / Q000378:metabolism
chemical_list: D000936:Antigen-Antibody Complex; D016207:Cytokines; D007166:Immunosuppressive Agents; D018836:Inflammation Mediators; D016328:NF-kappa B; D009842:Oligopeptides; D012333:RNA, Messenger; D044005:Tetrahydroisoquinolines; C082263:tyrosyl-1,2,3,4-tetrahydro-3-isoquinolinecarbonyl-phenylalanyl-phenylalanine; D007073:Immunoglobulin E; D006632:Histamine; D051546:Cyclooxygenase 2; D020928:Mitogen-Activated Protein Kinases; D001619:beta-N-Acetylhexosaminidases; D002118:Calcium