Dutch-type cerebral amyloid angiopathy (D-CAA) is a rare neurodegenerative/neurovascular disease caused by a point mutation in the amyloid precursor protein (APP) gene that leads to aggregation of... Show moreDutch-type cerebral amyloid angiopathy (D-CAA) is a rare neurodegenerative/neurovascular disease caused by a point mutation in the amyloid precursor protein (APP) gene that leads to aggregation of the amyloid beta peptide in the brain vasculature. It is characterized by intracerebral hemorrhages, infarcts, cognitive decline and vascular dementia. To date there are no therapies that prevent or delay D-CAA onset or progression. In this thesis we aimed to model the disease using patient-derived cell models, develop and test an RNA-targeting therapy and look into the mutated protein trafficking in the cell. Using D-CAA patient-derived induced pluripotent stem cells as template, we generated state-of-the-art 3D brain organoids and successfully modeled the amyloid beta aggregation and other D-CAA disease signatures, also found in the D-CAA human brain. We developed and tested an RNA-targeting therapy that showed efficient and significant reduction of the amyloid beta peptide in D-CAA patient-derived cells and control mice. Finally, when looking into the mutated APP protein trafficking we have found that the Dutch mutation affects the processing and trafficking of APP protein prior to the generation of the amyloid beta fragment, a phenotype that was reversed when the RNA-targeting therapy was applied. With the data generated in this thesis we hope to further advance the knowledge on D-CAA disease mechanisms as well as the possibility for therapeutics that will benefit D-CAA patients. Show less
Daoutsali, E.; Hailu, T.T.; Buijsen, R.A.M.; Pepers, B.A.; Graaf, L.M. van der; Verbeek, M.M.; ... ; Roon-Mom, W.M.C. van 2021
Dutch-type cerebral amyloid angiopathy (D-CAA) is a monogenic form of cerebral amyloid angiopathy and is inherited in an autosomal dominant manner. The disease is caused by a point mutation in exon... Show moreDutch-type cerebral amyloid angiopathy (D-CAA) is a monogenic form of cerebral amyloid angiopathy and is inherited in an autosomal dominant manner. The disease is caused by a point mutation in exon 17 of the amyloid precursor protein (APP) gene that leads to an amino acid substitution at codon 693. The mutation is located within the amyloid beta (A beta) domain of APP, and leads to accumulation of toxic A beta peptide in and around the cerebral vasculature. We have designed an antisense oligonucleotide (AON) approach that results in skipping of exon 17, generating a shorter APP isoform that lacks part of the A beta domain and the D-CAA mutation. We demonstrate efficient AON-induced skipping of exon 17 at RNA level and the occurrence of a shorter APP protein isoform in three different cell types. This resulted in a reduction of A beta 40 in neuronally differentiated, patient-derived induced pluripotent stem cells. AON-treated wild-type mice showed successful exon skipping on RNA and protein levels throughout the brain. These results illustrate APP splice modulation as a promising therapeutic approach for D-CAA. Show less
