title: Cell-to-cell transfer of SAA1 protein in a cell culture model of systemic AA amyloidosis.
abstract: Systemic AA amyloidosis arises from the misfolding of serum amyloid A1 (SAA1) protein and the deposition of AA amyloid fibrils at multiple sites within the body. Previous research already established that mononuclear phagocytes are crucial for the formation of the deposits in vivo and exposure of cultures of such cells to SAA1 protein induces the formation of amyloid deposits within the culture dish. In this study we show that both non-fibrillar and fibrillar SAA1 protein can be readily transferred between cultured J774A.1 cells, a widely used model of mononuclear phagocytes. We find that the exchange is generally faster with non-fibrillar SAA1 protein than with fibrils. Exchange is blocked if cells are separated by a membrane, while increasing the volume of cell culture medium had only small effects on the observed exchange efficiency. Taken together with scanning electron microscopy showing the presence of the respective types of physical interactions between the cultured cells, we conclude that the transfer of SAA1 protein depends on direct cell-to-cell contacts or tunneling nanotubes.
authors.affiliation: Institute of Protein Biochemistry, Ulm University, Helmholtzstr. 8/1, 89081 Ulm, Germany.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Claus
authors.affiliation: Institute of Protein Biochemistry, Ulm University, Helmholtzstr. 8/1, 89081 Ulm, Germany.
authors.forename: Ioana
authors.initials: I
authors.lastname: Puscalau-Girtu
authors.affiliation: Central Facility for Electron Microscopy, Ulm University, Albert-Einstein-Allee 11, 89069 Ulm, Germany.
authors.forename: Paul
authors.initials: P
authors.lastname: Walther
authors.affiliation: Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, Helmholtzstr. 20, 89081 Ulm, Germany.
authors.forename: Tatiana
authors.initials: T
authors.lastname: Syrovets
authors.affiliation: Institute of Pharmacology of Natural Products and Clinical Pharmacology, Ulm University, Helmholtzstr. 20, 89081 Ulm, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Simmet
authors.affiliation: Institute of Protein Biochemistry, Ulm University, Helmholtzstr. 8/1, 89081 Ulm, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Haupt
authors.affiliation: Institute of Protein Biochemistry, Ulm University, Helmholtzstr. 8/1, 89081 Ulm, Germany.
authors.forename: Marcus
authors.initials: M
authors.lastname: Fändrich
mesh_terms: D000682:Amyloid / Q000378:metabolism; D000686:Amyloidosis / Q000378:metabolism*; D000818:Animals; D002450:Cell Communication; D002478:Cells, Cultured; D051379:Mice; D010586:Phagocytes / Q000378:metabolism; D000685:Serum Amyloid A Protein / Q000378:metabolism*
chemical_list: D000682:Amyloid; C489995:Saa2 protein, mouse; D000685:Serum Amyloid A Protein