title: Chaperone nanobodies protect gelsolin against MT1-MMP degradation and alleviate amyloid burden in the gelsolin amyloidosis mouse model.
abstract: Gelsolin amyloidosis is an autosomal dominant incurable disease caused by a point mutation in the GSN gene (G654A/T), specifically affecting secreted plasma gelsolin. Incorrect folding of the mutant (D187N/Y) second gelsolin domain leads to a pathological proteolytic cascade. D187N/Y gelsolin is first cleaved by furin in the trans-Golgi network, generating a 68 kDa fragment (C68). Upon secretion, C68 is cleaved by MT1-MMP-like proteases in the extracellular matrix, releasing 8 kDa and 5 kDa amyloidogenic peptides which aggregate in multiple tissues and cause disease-associated symptoms. We developed nanobodies that recognize the C68 fragment, but not native wild type gelsolin, and used these as molecular chaperones to mitigate gelsolin amyloid buildup in a mouse model that recapitulates the proteolytic cascade. We identified gelsolin nanobodies that potently reduce C68 proteolysis by MT1-MMP in vitro. Converting these nanobodies into an albumin-binding format drastically increased their serum half-life in mice, rendering them suitable for intraperitoneal injection. A 12-week treatment schedule of heterozygote D187N gelsolin transgenic mice with recombinant bispecific gelsolin-albumin nanobody significantly decreased gelsolin buildup in the endomysium and concomitantly improved muscle contractile properties. These findings demonstrate that nanobodies may be of considerable value in the treatment of gelsolin amyloidosis and related diseases.
authors.affiliation: Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium.
authors.forename: Wouter
authors.initials: W
authors.lastname: Van Overbeke
authors.affiliation: Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium.
authors.forename: Adriaan
authors.initials: A
authors.lastname: Verhelle
authors.affiliation: Department of Movement and Sport Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium.
authors.forename: Inge
authors.initials: I
authors.lastname: Everaert
authors.affiliation: Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium.
authors.forename: Olivier
authors.initials: O
authors.lastname: Zwaenepoel
authors.affiliation: Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium.
authors.forename: Joël
authors.initials: J
authors.lastname: Vandekerckhove
authors.affiliation: Department of Pathology, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium.
authors.forename: Claude
authors.initials: C
authors.lastname: Cuvelier
authors.affiliation: Department of Movement and Sport Sciences, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium.
authors.forename: Wim
authors.initials: W
authors.lastname: Derave
authors.affiliation: Department of Biochemistry, Faculty of Medicine and Health Sciences, Ghent University, Ghent, Belgium.
authors.forename: Jan
authors.initials: J
authors.lastname: Gettemans
mesh_terms: D000682:Amyloid / Q000378:metabolism*; D000686:Amyloidosis / Q000378:metabolism*; D028226:Amyloidosis, Familial / Q000378:metabolism; D000818:Animals; D018033:Antibodies, Bispecific / Q000276:immunology / Q000378:metabolism; D000918:Antibody Specificity / Q000276:immunology; D004195:Disease Models, Animal; D018260:Gelsolin / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D053511:Matrix Metalloproteinase 14 / Q000378:metabolism*; D051379:Mice; D018832:Molecular Chaperones / Q000737:chemistry / Q000276:immunology / Q000378:metabolism*; D018485:Muscle Fibers, Skeletal / Q000378:metabolism / Q000473:pathology; D010455:Peptides / Q000276:immunology / Q000378:metabolism; D011485:Protein Binding; D054730:Protein Interaction Domains and Motifs; D059748:Proteolysis; D061905:Single-Domain Antibodies / Q000276:immunology / Q000378:metabolism*
chemical_list: D000682:Amyloid; D018033:Antibodies, Bispecific; D018260:Gelsolin; D018832:Molecular Chaperones; D010455:Peptides; D061905:Single-Domain Antibodies; D053511:Matrix Metalloproteinase 14