title: SHP-1-Pyk2-Src protein complex and p38 MAPK pathways independently regulate IL-10 production in lipopolysaccharide-stimulated macrophages.
abstract: The role of tyrosine phosphatase Src homology region 2 domain-containing phosphatase (SHP)-1 in LPS-activated cytokine production and inflammation was investigated by determining TNF-α and IL-10 production in splenic macrophages employing SHP-1-null (me/me) mouse model. LPS-stimulated me/me splenic macrophages secreted significantly less IL-10 with concomitantly elevated levels of TNF-α compared with wild-type (WT) macrophages irrespective of LPS dose and duration of stimulation. IL-10 significantly inhibited LPS-induced TNF-α production in both me/me and WT macrophages. The critical requirement for SHP-1 in regulating LPS-induced IL-10 and TNF-α production was confirmed by interfering with SHP-1 expression in WT macrophages and by reconstituting me/me macrophages with the SHP-1 gene. To delineate the role of SHP-1 in positive regulation of LPS-induced IL-10 production, signaling proteins representing SHP-1 targets were examined. The results reveal that tyrosine kinases Src and proline-rich tyrosine kinase 2 (Pyk2) regulate SHP-1-dependent LPS-induced IL-10 production and infer that optimal LPS-induced IL-10 production requires an assembly of a protein complex consisting of SHP-1-Pyk2-Src proteins. Moreover, LPS-induced IL-10 production also requires activation of the p38 MAPK independent of SHP-1 function. Overall, to our knowledge our results show for the first time that SHP-1 acts as a positive regulator of LPS-induced IL-10 production in splenic macrophages through two distinct and independent SHP-1-Pyk2-Src and p38 MAPK pathways.
authors.affiliation: Department of Biochemistry, Microbiology, and Immunology, University of Ottawa, Ottawa, Ontario K1H 8M5, Canada.
authors.forename: Chinonso
authors.initials: C
authors.lastname: Okenwa
authors.forename: Ashok
authors.initials: A
authors.lastname: Kumar
authors.forename: Dorothy
authors.initials: D
authors.lastname: Rego
authors.forename: Yulia
authors.initials: Y
authors.lastname: Konarski
authors.forename: Ladan
authors.initials: L
authors.lastname: Nilchi
authors.forename: Kathryn
authors.initials: K
authors.lastname: Wright
authors.forename: Maya
authors.initials: M
authors.lastname: Kozlowski
mesh_terms: D000818:Animals; D015153:Blotting, Western; D004797:Enzyme-Linked Immunosorbent Assay; D051418:Focal Adhesion Kinase 2 / Q000276:immunology* / Q000378:metabolism; D047468:Immunoprecipitation; D016753:Interleukin-10 / Q000096:biosynthesis*; D008070:Lipopolysaccharides / Q000276:immunology; D020935:MAP Kinase Signaling System; D008262:Macrophage Activation / Q000276:immunology; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism; D051379:Mice; D018345:Mice, Knockout; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6 / Q000276:immunology* / Q000378:metabolism; D034741:RNA, Small Interfering; D014161:Transduction, Genetic; D014162:Transfection; D048051:p38 Mitogen-Activated Protein Kinases / Q000276:immunology; D019061:src-Family Kinases / Q000276:immunology* / Q000378:metabolism
chemical_list: D008070:Lipopolysaccharides; D034741:RNA, Small Interfering; D016753:Interleukin-10; D051418:Focal Adhesion Kinase 2; C496053:Ptk2b protein, mouse; D019061:src-Family Kinases; D048051:p38 Mitogen-Activated Protein Kinases; D053824:Protein Tyrosine Phosphatase, Non-Receptor Type 6; C509248:Ptpn6 protein, mouse