A Long‐Living Bioengineered Neural Tissue Platform to Study Neurodegeneration

Abstract

The prevalence of dementia and other neurodegenerative diseases continues to rise as age demographics in the population shift, inspiring the development of long‐term tissue culture systems with which to study chronic brain disease. Here, it is investigated whether a 3D bioengineered neural tissue model derived from human induced pluripotent stem cells (hiPSCs) can remain stable and functional for multiple years in culture. Silk‐based scaffolds are seeded with neurons and glial cells derived from hiPSCs supplied by human donors who are either healthy or have been diagnosed with Alzheimer's disease. Cell retention and markers of stress remain stable for over 2 years. Diseased samples display decreased spontaneous electrical activity and a subset displays sporadic‐like indicators of increased pathological β‐amyloid and tau markers characteristic of Alzheimer's disease with concomitant increases in oxidative stress. It can be concluded that the long‐term stability of the platform is suited to study chronic brain disease including neurodegeneration.

A 3D Tissue Model of Traumatic Brain Injury with Excitotoxicity That Is Inhibited by Chronic Exposure to Gabapentinoids

“…The seeding procedure was performed in 96-well plates, which were incubated (37 • C, 5% CO 2 , and 95% relative humidity) for 24 h. The cell-containing scaffolds were then transferred to new 96-well plates and embedded within a collagen type-I (rat tail) hydrogel (3 mg/mL). The structural integrity of the silk scaffold material and collagen-based hydrogel were recently confirmed to remain stable for over 2 years in culture conditions [38]. After a 30 min gelation period within the incubator, samples were transferred to 24-well plates and maintained in 1.5 mL of fresh medium composed of a Neurobasal™ medium (Gibco™, Thermo Fisher, Grand Island, NY, USA) with 1% v/v l-glutamine (GlutaMAX™, Thermo Fisher, Waltham, MA, USA), 2% v/v B27 supplement (Thermo Fisher), and 1% v/v penicillin-streptomycin (Corning™, Cellgro™, Cambridge, MA, USA; antibiotic solution).…”

Modeling neurodegenerative diseases with cerebral organoids and other three-dimensional culture systems: focus on Alzheimer’s disease

“…3D cultures have also been developed with modified hydrogel-based scaffolds [41,42], such as StarPEG-heparin hydrogel that promotes proliferation of neural stem cells [41]. Upon Aβ42 treatment, the spontaneous electrical activity of these cultures was disrupted, resulting in dystrophic axons, matrix stiffness and decrease in synaptic plasticity [41].…”

“…Another model used a silk fibroin porous scaffold with intercalated hydrogel to culture neurons derived from a SAD patient [42]. This culture demonstrated a decrease in spontaneous electrical activity and an increase in Aβ42/40 ratio [42]. In contrast, AD-like CO models are designed to grow in a self-organizing manner [43].…”

“…Treatment with IL-4 suppressed this kynurenine aminotransferase -mediated Aβ toxicity [ 41 ]. Another model used a silk fibroin porous scaffold with intercalated hydrogel to culture neurons derived from a SAD patient [ 42 ]. This culture demonstrated a decrease in spontaneous electrical activity and an increase in Aβ42/40 ratio [ 42 ].…”

“…Similarly, 3D cultures with variants in the APP transmembrane region showed either high (I45F variant) or low pTau levels (I47F variant) correlating with Aβ42/40 ratios [ 37 ]. Aβ42 treatment in starPEG-heparin hydrogel-based 3D culture and a silk fibroin-based 3D culture of SAD hiPSC-derived neurons also showed an increase in pTau (T231) [ 41 ] (S199) [ 42 ] levels with Gallyas- and Thioflavin S-positive NFTs [ 41 ]. Treatment of these cultures with β and γ-secretase inhibitors caused a decrease in both Aβ and tau pathology [ 35 ].…”