The presence of BBB hastens neuronal differentiation of cerebral organoids - the potential role of endothelial derived BDNF

Abstract

Despite remaining the best in vitro model to resemble the human brain, a weakness of human cerebral organoids is the lack of the endothelial component that in vivo organizes in the blood brain barrier (BBB). Since the BBB is crucial to control the microenvironment of the nervous system, this study proposes a co-culture BBB and cerebral organoids. We utilized a BBB model consisting of primary brain microvascular endothelial cells and astrocytes in a transwell system. Starting from induced Pluripotent Stem Cells (iPSCs) we generated human cerebral organoids which were then cultured in the absence or presence of an in vitro model of BBB. We evaluated if the presence of the BBB influences the maturation of cerebral organoids. By morphological analysis, it emerges that in the presence of the BBB the cerebral organoids are better organized than controls in the absence of the BBB. This effect seems to be driven by Brain Derived Neurotrophic Factor (BDNF), a neurotrophic factor released by the endothelial component of the BBB, which is involved in neurodevelopment, neuroplasticity and neurosurvival. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=108 SRC="FIGDIR/small/501119v1_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@483c47org.highwire.dtl.DTLVardef@6d5976org.highwire.dtl.DTLVardef@10c5545org.highwire.dtl.DTLVardef@b2610b_HPS_FORMAT_FIGEXP M_FIG C_FIG The current culture model of human cerebral organoids does not require the presence of a BBB (left side). However, the BBB is an important source of BDNF, which is crucial for neurodevelopment and brain health. The cerebral organoids co-cultured for 4 days in the presence of the BBB show a higher cortical organization than the organoids cultured in the absence of the BBB, as illustrated on the right.