title: Expression of Notch signaling components in cutaneous foreign body and sarcoidal granulomas and fusing macrophages.
abstract: The evolutionarily conserved Notch signaling pathway affects tissue-specific cell differentiation, proliferation, and apoptosis. In the immune system, Notch has been implicated in the development and function of both adoptive and innate immune cells. Notch signaling is initiated by Notch receptor binding to cognate ligands, which results in the enzymatic cleavage and intranuclear translocation of the intracellular domain of Notch receptor (ICN). Recent murine models of chronic inflammation highlighted a critical role for a Notch ligand, Delta-like ligand (Dll)-4, in granuloma formation. In this study, we aimed to assess Notch-1 receptor activation and Dll4 expression in human cutaneous granulomas and in cultured human macrophages and multinucleated giant cells. ICN1 and Dll4 expression was evaluated by immunohistochemistry of cutaneous foreign body (n = 15) and sarcoidal (n = 19) granulomas. The results showed consistent intranuclear staining for ICN1 in foreign body but not in sarcoidal granulomas and strong cytoplasmic staining for Dll4 in mononuclear histiocytes and multinucleate giant cells in both types of granulomas. Additionally, immunofluorescence confocal microscopy showed ICN1 and Dll4 expression by cultured human macrophages undergoing fusion in the presence of granulocyte-macrophage colony-stimulating factor and interleukin-4. These findings indicate a potential role for the Notch-1-Dll4 signaling pathway in foreign body-induced granulomatous reactions and possibly distinct Notch pathway utilization in sarcoidal granulomas.
authors.affiliation: Departments of *Dermatology, and †Pathology and Laboratory Medicine, Hospital of University of Pennsylvania, Philadelphia, PA; and ‡Department of Pathology and Immunology, Washington University School of Medicine in St Louis, St Louis, MO.
authors.forename: Javier R
authors.initials: JR
authors.lastname: Rangel
authors.forename: Yoonjie
authors.initials: Y
authors.lastname: Chung
authors.forename: Misha
authors.initials: M
authors.lastname: Rosenbach
authors.forename: Amy F
authors.initials: AF
authors.lastname: Ziober
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Zhang
authors.forename: Andras
authors.initials: A
authors.lastname: Schaffer
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D002135:Calcium-Binding Proteins; D006099:Granuloma / Q000378:metabolism / Q000473:pathology; D015745:Granuloma, Foreign-Body / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism*; D008264:Macrophages / Q000378:metabolism* / Q000473:pathology; D051881:Receptor, Notch1 / Q000378:metabolism*; D012507:Sarcoidosis / Q000378:metabolism* / Q000473:pathology; D015398:Signal Transduction / Q000502:physiology; D012871:Skin Diseases / Q000378:metabolism* / Q000473:pathology
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002135:Calcium-Binding Proteins; C424126:DLL4 protein, human; D036341:Intercellular Signaling Peptides and Proteins; D051881:Receptor, Notch1