Establishment of a Human iPSC- and Nanofiber-Based Microphysiological Blood–Brain Barrier System

Abstract

The blood–brain barrier (BBB) is an active and complex diffusion barrier that separates the circulating blood from the brain and extracellular fluid, regulates nutrient transportation, and provides protection against various toxic compounds and pathogens. Creating an in vitro microphysiological BBB system, particularly with relevant human cell types, will significantly facilitate the research of neuropharmaceutical drug delivery, screening, and transport, as well as improve our understanding of pathologies that are due to BBB damage. Currently, most of the in vitro BBB models are generated by culturing rodent astrocytes and endothelial cells, using commercially available transwell membranes. Those membranes are made of plastic biopolymers that are nonbiodegradable, porous, and stiff. In addition, distinct from rodent astrocytes, human astrocytes possess unique cell complexity and physiology, which are among the few characteristics that differentiate human brains from rodent brains. In this study, we established a novel human BBB microphysiologocal system, consisting of a three-dimensionally printed holder with a electrospun poly(lactic-co-glycolic) acid (PLGA) nanofibrous mesh, a bilayer coculture of human astrocytes, and endothelial cells, derived from human induced pluripotent stem cells (hiPSCs), on the electrospun PLGA mesh. This human BBB model achieved significant barrier integrity with tight junction protein expression, an effective permeability to sodium fluorescein, and higher transendothelial electrical resistance (TEER) comparing to electrospun mesh-based counterparts. Moreover, the coculture of hiPSC-derived astrocytes and endothielial cells promoted the tight junction protein expression and the TEER value. We further verified the barrier functions of our BBB model with antibrain tumor drugs (paclitaxel and bortezomib) and a neurotoxic peptide (amyloid β 1–42). The human microphysiological system generated in this study will potentially provide a new, powerful tool for research on human BBB physiology and pathology.

Concise review: Harnessing iPSC-derived cells for ischemic heart disease treatment

“…Apart from cardiomyocytes, hiPSCs can also be differentiated into vascular cells, that is, endothelial cells (ECs), smooth muscle cells (SMCs), and pericytes. [22,23] These hiPSC derived vascular cells have also been used, either with hiPSC-CMs or alone, to vascularize the engineered tissue or promote the revascularization of injured myocardium.…”

In Vitro Blood–Brain Barrier-Integrated Neurological Disorder Models Using a Microfluidic Device

“…Moreover, these cells showed tube formation, low-density lipoprotein uptake, and high TEER value of >3000 ohm•cm 2 , similar to the vascular endothelial cells in vivo. Qi et al also used human induced pluripotent stem cells (iPSCs) that differentiated into two different kinds of cells, astrocytes and vascular endothelial cells [40] (Figure 1b). For mimicking the human microphysiological BBB system more closely, poly(lactic-co-glycolic) acid (PLGA) nanofiber was used to form a nanofibrous mesh on a 3D printed holder.…”

“…(c) 2D Transwell-based BBB model with isogenic human model by iPSCs. Reproduced with permission from[40]. Copyright 2017, American Association for the Advancement of Science (AAAS).…”

Studying Heterotypic Cell–Cell Interactions in the Human Brain Using Pluripotent Stem Cell Models for Neurodegeneration

“…Human brain microvessels isolated from brain specimens or BMECs derived from hiPSCs have been used to establish in vitro BBB models (Table 1) [38,39,65,66]. Based on the procedure developed by Lippmann et al for differentiating BMECs from hiPSCs [67], Katt et al reported a modified protocol and generated the brain endothelial cells with BBB phenotype [68,69].…”

“…HiPSCs are the ideal cell source for BBB modeling due to: (1) the unlimited availability of hiPSCs (self-renewal ability); and (2) the capability of patient-derived hiPSCs for the investigations of the underlying cellular mechanisms related to neurodegenerative diseases. Recently, a number of in vitro multicellular BBB models have been developed to investigate the crucial role of BBB in brain development, function, and disease progression (Table 1) [38,39,65,66,74]. Systematic comparison of different multicellular models showed the beneficial effects of pericytes on BBB tightness [38].…”