title: Human IgGs induce synthesis and secretion of IgGs and neonatal Fc receptor in human umbilical vein endothelial cells.
abstract: Human IgGs are increasingly used in the therapy of many different immune and inflammatory diseases, however their mechanism of action still remains unclear in most diseases. To gain insight into the mechanism by which IgGs might also exert their effects on endothelial cells, we tested human IgGs on human umbilical vein endothelial cells (HUVECs). IgGs induced a time-dependent increase in the synthesis and secretion of IgGs, together with a marked angiogenic-like transformation of HUVECs that was maximal after a 20-h incubation. IgGs stimulated IG gene transcription without affecting the process of gene rearrangement, already present in control HUVECs. The mechanism involved the activation of transcription factors with the increased expression of HSP90, HSP70 and inactive MMP-9 responsible for the phenotypic differentiation associated with the most intense IgG synthesis and secretion. However, even a short incubation with IgGs followed by recovery of cells was sufficient to trigger and sustain in time the synthesis and secretion of new IgGs, independently of the angiogenic-like transformation visible only when cells were continuously exposed to IgGs. Under the stimulus of IgGs, specific secretory pathways were also activated in HUVECs together with the expression of FcRn, which was always associated with IgGs of new synthesis, forming complexes that were also secreted. Our results disclose a so far unknown and unexpected mechanism of IgGs on HUVECs that behave as Ig-producing immune cells. Results might have relevance for the effects that IgGs also exert in vivo in physiological conditions.
authors: Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Pharmacology Building, L.go E. Meneghetti 2, 35131 Padua, Italy.
authors: Giulia
authors: G
authors: Frigo
authors: Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Pharmacology Building, L.go E. Meneghetti 2, 35131 Padua, Italy.
authors: Elisa
authors: E
authors: Tramentozzi
authors: Scientific Institute, IRCCS Eugenio Medea, Conegliano, Treviso, Italy.
authors: Genny
authors: G
authors: Orso
authors: Department of Medicine, University of Padua, via Giustiniani 2, 35128 Padua, Italy.
authors: Giulio
authors: G
authors: Ceolotto
authors: Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Pharmacology Building, L.go E. Meneghetti 2, 35131 Padua, Italy.
authors: Andrea
authors: A
authors: Pagetta
authors: Department of Surgery Oncology and Gastroenterology, University of Padua, Via Gattamelata 64, Padua, Italy.
authors: Camilla
authors: C
authors: Stagni
authors: Immunology and Molecular Oncology Unit, Veneto Institute of Oncology, IOV-IRCCS, Via Gattamelata 64, Padua, Italy.
authors: Chiara
authors: C
authors: Menin
authors: Department of Surgery Oncology and Gastroenterology, University of Padua, Via Gattamelata 64, Padua, Italy; Immunology and Molecular Oncology Unit, Veneto Institute of Oncology, IOV-IRCCS, Via Gattamelata 64, Padua, Italy. Electronic address: antonio.rosato@unipd.it.
authors: Antonio
authors: A
authors: Rosato
authors: Department of Pharmaceutical and Pharmacological Sciences, University of Padua, Pharmacology Building, L.go E. Meneghetti 2, 35131 Padua, Italy. Electronic address: paola.finotti@unipd.it.
authors: Paola
authors: P
authors: Finotti
mesh_terms: D000936:Antigen-Antibody Complex / Q000378:metabolism; D002454:Cell Differentiation; D004730:Endothelium, Vascular / Q000276:immunology*; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism; D015395:Histocompatibility Antigens Class I / Q000378:metabolism*; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D007074:Immunoglobulin G / Q000276:immunology / Q000378:metabolism*; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D018919:Neovascularization, Physiologic; D000090063:Proto-Oncogene Mas; D011961:Receptors, Fc / Q000378:metabolism*; D015398:Signal Transduction
chemical_list: D000936:Antigen-Antibody Complex; D018840:HSP70 Heat-Shock Proteins; D018841:HSP90 Heat-Shock Proteins; D015395:Histocompatibility Antigens Class I; D007074:Immunoglobulin G; C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D011961:Receptors, Fc; D020780:Matrix Metalloproteinase 9; C100688:Fc receptor, neonatal
keywords: Cell differentiation; Heat shock proteins; Immunoglobulin gene; MEK-ERK pathway; Proto-oncogene proteins c-akt; Secretory pathway; Vascular endothelium