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
Coomans, C.; Saaltink, D.J.; Deboer, T.; Tersteeg, M.; Lanooij, S.; Schneider, A.F.; ... ; Vreugdenhil, E. 2021
We have recently identified a novel plasticity protein, doublecortin-like (DCL), that is specifically expressed in the shell of the mouse suprachiasmatic nucleus (SCN). DCL is implicated in... Show moreWe have recently identified a novel plasticity protein, doublecortin-like (DCL), that is specifically expressed in the shell of the mouse suprachiasmatic nucleus (SCN). DCL is implicated in neuroplastic events, such as neurogenesis, that require structural rearrangements of the microtubule cytoskeleton, enabling dynamic movements of cell bodies and dendrites. We have inspected DCL expression in the SCN by confocal microscopy and found that DCL is expressed in GABA transporter-3 (GAT3)-positive astrocytes that envelope arginine vasopressin (AVP)-expressing cells. To investigate the role of these DCL-positive astrocytes in circadian rhythmicity, we have used transgenic mice expressing doxycycline-induced short-hairpin (sh) RNA's targeting DCL mRNA (DCL knockdown mice). Compared with littermate wild type (WT) controls, DCL-knockdown mice exhibit significant shorter circadian rest-activity periods in constant darkness and adjusted significantly faster to a jet-lag protocol. As DCL-positive astrocytes are closely associated with AVP-positive cells, we analyzed AVP expression in DCL-knockdown mice and in their WT littermates by 3D reconstructions and transmission electron microscopy (TEM). We found significantly higher numbers of AVP-positive cells with increased volume and more intensity in DCL-knockdown mice. We found alterations in the numbers of dense core vesicle-containing neurons at ZT8 and ZT20 suggesting that the peak and trough of neuropeptide biosynthesis is dampened in DCL-knockdown mice compared to WT littermates. Together, our data suggest an important role for the astrocytic plasticity in the regulation of circadian rhythms and point to the existence of a specific DCL+ astrocyte-AVP(+) neuronal network located in the dorsal SCN implicated in AVP biosynthesis. Show less
