3D bioengineered neural tissue generated from patient-derived iPSCs develops time-dependent phenotypes and transcriptional features of Alzheimer’s disease

Abstract

Background Current models to study Alzheimer's disease (AD) include cell cultures and animal models. Human diseases, however, are often poorly reproduced in animal models. Developing techniques to differentiate human brain cells from induced pluripotent stem cells (iPSCs) provides a novel approach to studying AD. Three-dimensional (3D) cultures to model AD are represented by organoids, neurospheroids, and scaffold-based cultures. Methods We developed a 3D bioengineered model of iPSC-derived neural tissue that combines a porous scaffold composed of silk fibroin protein with an intercalated collagen hydrogel to support the growth of neurons and glial cells into complex and functional networks. This biomaterial scaffold, designed to match the mechanical properties of brain tissue, can support 3D neural cultures for an extended time without necrosis, a fundamental requisite for aging studies. We have optimized our protocol by seeding neural precursor cells (NPCs) into these scaffolds. Having NPCs stocks derived from multiple subjects allows synchronization of their differentiation and minimizes experimental variability. Cultures were generated from iPSC lines obtained from two subjects carrying the familial AD (FAD) APP London mutation, two well-studied control lines, and an isogenic control. Cultures were analyzed at 2 and 4.5 months. Results An elevated Aβ42/40 ratio was detected in FAD cultures at both time points, as previously reported in 2D cultures derived from the same FAD lines. Extracellular Aβ42 deposition and enhanced neuronal excitability were observed in FAD culture at 4.5 months. Notably, neuronal hyperexcitability has been described in AD patients early in the disease. Transcriptomic analysis revealed deregulation of multiple gene sets in FAD samples. Such alterations were similar to those observed in human AD brains in a large study that performed a co-expression meta-analysis of harmonized data from Accelerating Medicines Partnership for Alzheimer's Disease (AMP-AD) across three independent cohorts. Conclusions Our 3D tissue model supports the differentiation of healthy iPSC-derived cultures in a porous silk-collagen composite sponge with an optically clear central region. This design facilitates nutrient delivery to meet the metabolic demand of long-term cultures. These data provide evidence that our bioengineered model from patient-derived FAD iPSCs develops AD-related phenotypes, including AD transcriptomic features. Thus, it can represent a valuable model for studying AD-related pathomechanisms.

Adenosine deficiency facilitates CA1 synaptic hyperexcitability in the presymptomatic phase of a knock in mouse model of Alzheimer’s disease

“…Alzheimer's disease (AD) is a progressive neurodegenerative condition marked by the abnormal buildup of amyloid beta (Aβ) plaques, the formation of neurofibrillary tau tangles, and progressive neural degeneration 1 . Along with the hallmarks of the disease, neuronal hyperactivity has been reported in patients, animal models and in patientderived cell cultures [2][3][4][5][6][7][8][9][10][11][12] . Previous studies 13 have found that both sporadic and familial AD patients exhibit increased cortical-hippocampal activity, occurrence of seizures during the early phases of the prodromal stage [14][15][16] and faster cognitive decline in patients that exhibit subclinical epileptiform activity 17,18 .…”