title: An ER-directed gelsolin nanobody targets the first step in amyloid formation in a gelsolin amyloidosis mouse model.
abstract: Hereditary gelsolin amyloidosis is an autosomal dominantly inherited amyloid disorder. A point mutation in the GSN gene (G654A being the most common one) results in disturbed calcium binding by the second gelsolin domain (G2). As a result, the folding of G2 is hampered, rendering the mutant plasma gelsolin susceptible to a proteolytic cascade. Consecutive cleavage by furin and MT1-MMP-like proteases generates 8 and 5 kDa amyloidogenic peptides that cause neurological, ophthalmological and dermatological findings. To this day, no specific treatment is available to counter the pathogenesis. Using GSN nanobody 11 as a molecular chaperone, we aimed to protect mutant plasma gelsolin from furin proteolysis in the trans-Golgi network. We report a transgenic, GSN nanobody 11 secreting mouse that was used for crossbreeding with gelsolin amyloidosis mice. Insertion of the therapeutic nanobody gene into the gelsolin amyloidosis mouse genome resulted in improved muscle contractility. X-ray crystal structure determination of the gelsolin G2:Nb11 complex revealed that Nb11 does not directly block the furin cleavage site. We conclude that nanobodies can be used to shield substrates from aberrant proteolysis and this approach might establish a novel therapeutic strategy in amyloid diseases.
authors.affiliation: Department of Biochemistry, Faculty of Medicine and Health Sciences.
authors.forename: Wouter
authors.initials: W
authors.lastname: Van Overbeke
authors.affiliation: Institute of Molecular and Cellular Biology, A*STAR, Biopolis, Singapore 138673, Singapore.
authors.forename: Jantana
authors.initials: J
authors.lastname: Wongsantichon
authors.affiliation: Department of Movement and Sport Sciences, Faculty of Medicine and Health Sciences.
authors.forename: Inge
authors.initials: I
authors.lastname: Everaert
authors.affiliation: Department of Biochemistry, Faculty of Medicine and Health Sciences.
authors.forename: Adriaan
authors.initials: A
authors.lastname: Verhelle
authors.affiliation: Department of Biochemistry, Faculty of Medicine and Health Sciences.
authors.forename: Olivier
authors.initials: O
authors.lastname: Zwaenepoel
authors.affiliation: Department of Chemistry and Centre for Blood Research, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Anantasak
authors.initials: A
authors.lastname: Loonchanta
authors.affiliation: Department of Chemistry and Centre for Blood Research, Life Sciences Institute, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Leslie D
authors.initials: LD
authors.lastname: Burtnick
authors.affiliation: Department of Biochemistry, Faculty of Medicine and Health Sciences.
authors.forename: Ariane
authors.initials: A
authors.lastname: De Ganck
authors.affiliation: Department for Molecular Biomedical Research, VIB, Ghent, Belgium, Department of Biomedical Molecular Biology and.
authors.forename: Tino
authors.initials: T
authors.lastname: Hochepied
authors.affiliation: Department of Biomedical Molecular Biology and Vascular Cell Biology Unit, VIB Inflammation Research Centre, Ghent, Belgium and Mammalian Functional Genetics Laboratory, Division of Blood Cancers, Australian Centre for Blood Diseases, Department of Clinical Haematology, Monash University and Alfred Health Centre, Melbourne, Australia.
authors.forename: Jody
authors.initials: J
authors.lastname: Haigh
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.
authors.forename: Wim
authors.initials: W
authors.lastname: Derave
authors.affiliation: Institute of Molecular and Cellular Biology, A*STAR, Biopolis, Singapore 138673, Singapore, Department of Biochemistry, National University of Singapore, 8 Medical Drive, Singapore 117597, Singapore, jan.gettemans@ugent.be rrobinson@imcb.a-star.edu.sg.
authors.forename: Robert C
authors.initials: RC
authors.lastname: Robinson
authors.affiliation: Department of Biochemistry, Faculty of Medicine and Health Sciences, jan.gettemans@ugent.be rrobinson@imcb.a-star.edu.sg.
authors.forename: Jan
authors.initials: J
authors.lastname: Gettemans
mesh_terms: D000682:Amyloid / Q000378:metabolism*; D028226:Amyloidosis, Familial / Q000235:genetics / Q000378:metabolism* / Q000503:physiopathology; D000818:Animals; D004195:Disease Models, Animal; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D045683:Furin / Q000378:metabolism; D018260:Gelsolin / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015870:Gene Expression; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D008822:Mice, Transgenic; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000378:metabolism / Q000503:physiopathology; D009154:Mutation; D011485:Protein Binding; D011487:Protein Conformation; D059748:Proteolysis / Q000187:drug effects; D061905:Single-Domain Antibodies / Q000737:chemistry / Q000494:pharmacology*; D021601:trans-Golgi Network / Q000378:metabolism
chemical_list: D000682:Amyloid; D018260:Gelsolin; D061905:Single-Domain Antibodies; D045683:Furin