title: Monitoring liver macrophages using nanobodies targeting Vsig4: concanavalin A induced acute hepatitis as paradigm.
abstract: Kupffer cells (KCs) are liver resident macrophages which are important for tissue homeostasis and have been implicated in immunogenic, tolerogenic and pathogenic immune reactions depending on the insult. These cells and the biomarkers they express thus represent interesting in vivo sensors for monitoring liver inflammation. In the current study, we explored whether KCs can be monitored non-invasively using single-photon-emission computed tomography (SPECT) with (99m)Tc labeled nanobodies (Nbs) targeting selected biomarkers. Nbs targeting V-set and immunoglobulin domain-containing 4 (Vsig4) or macrophage mannose receptor (MMR) accumulated in the liver of untreated mice. The liver targeting of anti-Vsig4 Nbs, but not anti-MMR Nbs, was blunted upon depletion of macrophages, highlighting specificity of anti-Vsig4 Nbs for liver macrophage imaging. Ex vivo flow cytometry and immunohistochemistry analysis confirmed that anti-Vsig4 Nbs specifically targeted KCs but no other cell types in the liver. Upon induction of acute hepatitis using concanavalin A (ConA), down-regulation of the in vivo imaging signal obtained using anti-Vsig4 Nbs reflected reduction in KC numbers and transient modulation of Vsig4 expression on KCs. Overall, these results indicate that Nbs targeting Vsig4 as molecular imaging biomarker enable non-invasive monitoring of KCs during hepatic inflammation.
authors.affiliation: Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium; VIB Laboratory of Myeloid Cell Immunology, Brussels, Belgium; Department of Biochemistry and Molecular Biology, Health Science Center, Xi'an Jiaotong University, Xi'an, China.
authors.forename: Fang
authors.initials: F
authors.lastname: Zheng
authors.affiliation: Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium; In Vivo Cellular and Molecular Imaging Center, Vrije Universiteit Brussel, Brussels, Belgium.
authors.forename: Nick
authors.initials: N
authors.lastname: Devoogdt
authors.affiliation: Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium; VIB Laboratory of Myeloid Cell Immunology, Brussels, Belgium.
authors.forename: Amanda
authors.initials: A
authors.lastname: Sparkes
authors.affiliation: Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium; VIB Laboratory of Myeloid Cell Immunology, Brussels, Belgium.
authors.forename: Yannick
authors.initials: Y
authors.lastname: Morias
authors.affiliation: Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium; VIB Laboratory of Myeloid Cell Immunology, Brussels, Belgium.
authors.forename: Chloé
authors.initials: C
authors.lastname: Abels
authors.affiliation: Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium; VIB Laboratory of Myeloid Cell Immunology, Brussels, Belgium.
authors.forename: Benoit
authors.initials: B
authors.lastname: Stijlemans
authors.affiliation: In Vivo Cellular and Molecular Imaging Center, Vrije Universiteit Brussel, Brussels, Belgium; Department of Nuclear Medicine, UZ Brussel, Vrije Universtiteit Brussel, Brussels, Belgium.
authors.forename: Tony
authors.initials: T
authors.lastname: Lahoutte
authors.affiliation: Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium; VIB Structural Biology Research Center, Vrije Universiteit Brussel, Brussels, Belgium.
authors.forename: Serge
authors.initials: S
authors.lastname: Muyldermans
authors.affiliation: Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium; VIB Laboratory of Myeloid Cell Immunology, Brussels, Belgium.
authors.forename: Patrick
authors.initials: P
authors.lastname: De Baetselier
authors.affiliation: Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium; VIB Laboratory of Myeloid Cell Immunology, Brussels, Belgium.
authors.forename: Steve
authors.initials: S
authors.lastname: Schoonooghe
authors.affiliation: Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium; VIB Laboratory of Myeloid Cell Immunology, Brussels, Belgium.
authors.forename: Alain
authors.initials: A
authors.lastname: Beschin
authors.affiliation: Laboratory of Cellular and Molecular Immunology, Vrije Universiteit Brussel, Brussels, Belgium; VIB Laboratory of Myeloid Cell Immunology, Brussels, Belgium. Electronic address: Geert.Raes@vib-vub.be.
authors.forename: Geert
authors.initials: G
authors.lastname: Raes
mesh_terms: D000208:Acute Disease; D000818:Animals; D000941:Antigens / Q000276:immunology; D000954:Antigens, Surface / Q000378:metabolism; D039481:CD11b Antigen / Q000378:metabolism; D002452:Cell Count; D003208:Concanavalin A / Q000009:adverse effects / Q000276:immunology; D016207:Cytokines / Q000378:metabolism; D004195:Disease Models, Animal; D015870:Gene Expression; D006506:Hepatitis A / Q000139:chemically induced / Q000276:immunology / Q000378:metabolism; D016130:Immunophenotyping; D007728:Kupffer Cells / Q000276:immunology* / Q000378:metabolism*; D008297:Male; D051379:Mice; D057054:Molecular Imaging; D010641:Phenotype; D011951:Receptors, Complement / Q000235:genetics / Q000276:immunology* / Q000378:metabolism*; D061905:Single-Domain Antibodies / Q000276:immunology*
chemical_list: D000941:Antigens; D000954:Antigens, Surface; D039481:CD11b Antigen; D016207:Cytokines; D011951:Receptors, Complement; D061905:Single-Domain Antibodies; C509992:VSIG4 protein, mouse; D003208:Concanavalin A
keywords: Complement receptor of the Ig superfamily (CRIg); Concanavalin A (ConA); Hepatitis; Kupffer cells; Nanobody; SPECT/μCT; V-set and immunoglobulin domain-containing 4 (Vsig4)