Human iPSC-based models of theCNS: attaining cellular biofidelitythrough conventional and advancedculture systems
Sammanfattning: Brain development is a highly orchestrated process that entails changes in microenvironmental cues and growth factor gradients, which set the tempo for proper development of the rudimentary structures of the brain and the generation of neurons,astrocytes, and oligodendrocytes. Another intricate feature of the brain is the bloodbrain barrier (BBB). The BBB consists of specialized endothelial cells that form asemipermeable barrier between the blood and the brain; hence, the BBB plays animportant part in protecting the brain from blood-borne pathogens. In vitro modeling is inherently limiting, an artificial microenvironment that is usually not in tunewith in vivo conditions. Thus, understanding these cues and growth factor conditions is pivotal for proper in vitro modeling and achieving cell biomimicry in vitro.Stem cell differentiation is highly amenable to growth factors and microenvironmental cues that can alter the expression of proteins. Advanced in vitro culturingconsiders microenvironmental cues and applies a more holistic aspect to in vitromodeling. This thesis evaluates microenvironmental cues in neural stem cell generation and astrocyte generation by employing induced pluripotent stem cells (iPSC).This thesis introduces a new protocol for generating human iPSC-derived astrocytesin under 28 days. By creating an astrocytogenic milieu, neural stem cells give riseto star-shaped astrocytes that encompass many traits previously unmet in iPSC-derived astrocytes, namely, ICAM-1 expression under inflammatory stimulation, glutathione synthesis and secretion. A follow-up study in this thesis presents a proteomic analysis between primary fetal astrocytes and iPSC-derived astrocytes. Microphysiological systems impart a more appropriate culturing microenvironment andinfluence cell fate and functionality. Another study of this thesis focuses on thedifferences between conventional and microphysiological culture systems in iPSCreprogramming and the generation of neural stem cells. Lastly, in vitro modeling ofthe blood-brain barrier (BBB) is also investigated. Specifically, 1) a human iPSCBBB-like model is used to evaluate the permeability of a drug delivery system basedon nanostructured lipid carriers and 2) a vessel-like structure with a 3D gliomamodel.
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