Preparation of organotypic brain slice cultures for the study of Alzheimer’s disease

Abstract

Alzheimer's disease, the most common cause of dementia, is a progressive neurodegenerative disorder characterised by amyloid-beta deposits in extracellular plaques, intracellular neurofibrillary tangles of aggregated tau, synaptic dysfunction and neuronal death. There are no cures for AD and current medications only alleviate some disease symptoms. Transgenic rodent models to study Alzheimer's mimic features of human disease such as age-dependent accumulation of abnormal beta-amyloid and tau, synaptic dysfunction, cognitive deficits and neurodegeneration. These models have proven vital for improving our understanding of the molecular mechanisms underlying AD and for identifying promising therapeutic approaches. However, modelling neurodegenerative disease in animals commonly involves aging animals until they develop harmful phenotypes, often coupled with invasive procedures. studies are also resource, labour, time and cost intensive. We have developed a novel organotypic brain slice culture model to study Alzheimer' disease which brings the potential of substantially reducing the number of rodents used in dementia research from an estimated 20,000 per year. We obtain 36 brain slices from each mouse pup, considerably reducing the numbers of animals required to investigate multiple stages of disease. This tractable model also allows the opportunity to modulate multiple pathways in tissues from a single animal. We believe that this model will most benefit dementia researchers in the academic and drug discovery sectors. We validated the slice culture model against aged mice, showing that the molecular phenotype closely mimics that displayed, albeit in an accelerated timescale. We showed beneficial outcomes following treatment of slices with agents previously shown to have therapeutic effects and we also identified new mechanisms of action of other compounds. Thus, organotypic brain slice cultures from transgenic mouse models expressing Alzheimer's disease-related genes may provide a valid and sensitive replacement for studies that do not involve behavioural analysis.

Lipopolysaccharide-induced neuroinflammation induces presynaptic disruption through a direct action on brain tissue involving microglia-derived interleukin 1 beta

“…Organotypic hippocampal slice cultures (OHSCs), where thin sections of the hippocampus are maintained in culture for several weeks [48–50], represent a crucial intermediate between in vivo and primary culture models and offer an excellent opportunity to explore mechanisms of synaptic disruption in neuroinflammation. Slice cultures retain hippocampal cytoarchitecture, synaptic connections and populations of supporting cell types in a system isolated from peripheral confounds that is amenable to experimental manipulation and observation [48–51].…”

POSCAbilities: The Application of the Prion Organotypic Slice Culture Assay to Neurodegenerative Disease Research

“…Similarly, Croft et al observed no sign of Aβ aggregates in hippocampal slice culture from 3xTg-AD mice, which express mutant human PS1, human APP with the Swedish mutation, and human mutant P301L tau. However, they found that these slices had accumulated similar levels of Aβ42 and phosphorylated tau by 28 days in culture as levels at 12 months in vivo, suggesting that these proteins accumulate on an accelerated time scale ex vivo [ 37 , 38 ].…”

“…For these same reasons, slice culture is far less expensive than in vivo studies. The accelerated accumulation of PrP Sc and pathology in POSCA and Aβ and tau in some AD slice culture models [ 37 ] also means that ex vivo experiments often take less time than in vivo studies.…”

“…By taking advantage of the prion-like nature of Aβ, tau, α-syn, TDP-43, SOD1, and mHtt, organotypic slice culture models of the corresponding neurodegenerative diseases have been significantly enhanced ( Table 2 ). For instance, while many transgenic mouse lines such as tgCRND8 and APPPS1 have been used to model and study the development of Aβ aggregation and associated AD pathology, nontreated organotypic slice cultures from these models fail to develop Aβ aggregates by the time that plaque development occurs in vivo [ 35 , 36 , 37 ]. However, aggregation can be induced in slice culture through addition of exogenous Aβ aggregates [ 36 , 40 ].…”

Beta secretase 1-dependent amyloid precursor protein processing promotes excessive vascular sprouting through NOTCH3 signaling

“…OBSCs initially retain a dense network of capillaries and neurovascular units alongside maintenance of neuronal architecture and non-neuronal cell populations (20)(21)(22). Crucially, OBSCs provide a 3dimensional culture system that supports the formation of new blood vessels and are amenable to pharmacological manipulation, live imaging and repeated measurements (23)(24)(25)(26). We and others have previously shown that OBSCs are powerful tools for investigating the progression of AD-like alterations including Aβ accumulation (27), synaptic disruption (24) and cerebrovascular damage (28).…”