Cerebral Amyloid Angiopathy (CAA) is one of the main causes of intracerebral hemorrhage (ICH) in the elderly, and affects millions of people worldwide. CAA is caused by the deposition of the... Show moreCerebral Amyloid Angiopathy (CAA) is one of the main causes of intracerebral hemorrhage (ICH) in the elderly, and affects millions of people worldwide. CAA is caused by the deposition of the protein Amyloid-β in the walls of the cerebral and leptomeningeal vessels, which leads to vessel fragility and eventually rupture. CAA has a variable disease course and can present with a spectrum of symptoms. There is currently no cure for CAA, and certain diagnosis during life remains challenging.This thesis has used data from patients with hereditary and non-hereditary (sporadic) CAA to investigate novel clinical and radiological (MRI) markers of CAA, and has used them to formulate a pathophysiologic framework for the temporal ordering of disease processes in CAA. Our results provide new insights in the disease cascade, can aid in diagnosing the disease and have important implications for future clinical trial design, aiding in the identification and timing of candidates for disease-modifying treatments and the choice for the appropriate biomarkers to monitor treatment effect. CAA is a disease with a complex disease cascade and a large variety in disease course, both clinically and radiologically. However, it is just this variety that gives hope for the future: if we find what drives variability in CAA we might find ways for disease modification, prevention and treatment, and identification of in vivo biomarkers with specificity for CAA are a vital part of this search. Show less
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.; Pepers, B.A.; Stamatakis, S.; Graaf, L.M. van der; Terwindt, G.M.; Parfitt, D.A.; ... ; Roon-Mom, W.M.C. van 2023
Introduction: ADutch-type cerebral amyloid angiopathy (D-CAA) is a hereditary brain disorder caused by a point mutation in the amyloid precursor protein (APP) gene. The mutation is located within... Show moreIntroduction: ADutch-type cerebral amyloid angiopathy (D-CAA) is a hereditary brain disorder caused by a point mutation in the amyloid precursor protein (APP) gene. The mutation is located within the amyloid beta (A beta) domain of APP and leads to A beta peptide accumulation in and around the cerebral vasculature. There lack of disease models to study the cellular and molecular pathological mechanisms of D-CAA together with the absence of a disease phenotype in vitro in overexpression cell models, as well as the limited availability of D-CAA animal models indicates the need for a D-CAA patient-derived model.Methods: We generated cerebral organoids from four D-CAA patients and four controls, cultured them up to 110 days and performed immunofluorescent and targeted gene expression analyses at two time points (D52 and D110).Results: D-CAA cerebral organoids exhibited A beta accumulations, showed enhanced neuronal and astrocytic gene expression and TGF beta pathway de-regulation.Conclusions: These results illustrate the potential of cerebral organoids as in vitro disease model of D-CAA that can be used to understand disease mechanisms of D-CAA and can serve as therapeutic intervention platform for various A beta-related disorders. 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
