Inflammatory Response and Exosome Biogenesis of Choroid Plexus Organoids Derived from Human Pluripotent Stem Cells

by Selleckchem | Jul 22 2023

The choroid plexus (ChP) is a complex structure in the human brain that is responsible for the secretion of cerebrospinal fluid (CSF) and forming the blood-CSF barrier (B-CSF-B). Human-induced pluripotent stem cells (hiPSCs) have shown promising results in the formation of brain organoids in vitro; however, very few studies to date have generated ChP organoids. In particular, no study has assessed the inflammatory response and the extracellular vesicle (EV) biogenesis of hiPSC-derived ChP organoids. In this study, the impacts of Wnt signaling on the inflammatory response and EV biogenesis of ChP organoids derived from hiPSCs was investigated. During days 10-15, bone morphogenetic protein 4 was added along with (+/-) CHIR99021 (CHIR, a small molecule GSK-3β inhibitor that acts as a Wnt agonist). At day 30, the ChP organoids were characterized by immunocytochemistry and flow cytometry for TTR (~72%) and CLIC6 (~20%) expression. Compared to the -CHIR group, the +CHIR group showed an upregulation of 6 out of 10 tested ChP genes, including CLIC6 (2-fold), PLEC (4-fold), PLTP (2-4-fold), DCN (~7-fold), DLK1 (2-4-fold), and AQP1 (1.4-fold), and a downregulation of TTR (0.1-fold), IGFBP7 (0.8-fold), MSX1 (0.4-fold), and LUM (0.2-0.4-fold). When exposed to amyloid beta 42 oligomers, the +CHIR group had a more sensitive response as evidenced by the upregulation of inflammation-related genes such as TNFα, IL-6, and MMP2/9 when compared to the -CHIR group. Developmentally, the EV biogenesis markers of ChP organoids showed an increase over time from day 19 to day 38. This study is significant in that it provides a model of the human B-CSF-B and ChP tissue for the purpose of drug screening and designing drug delivery systems to treat neurological disorders such as Alzheimer's disease and ischemic stroke.

Comments:

The study you described focuses on investigating the impacts of Wnt signaling on the inflammatory response and extracellular vesicle (EV) biogenesis of choroid plexus (ChP) organoids derived from human-induced pluripotent stem cells (hiPSCs). The ChP is responsible for the secretion of cerebrospinal fluid (CSF) and forms the blood-CSF barrier (B-CSF-B) in the human brain.

To generate the ChP organoids, hiPSCs were differentiated, and during days 10-15 of the differentiation process, bone morphogenetic protein 4 (BMP4) was added along with CHIR99021 (CHIR), a small molecule inhibitor of GSK-3β that acts as a Wnt agonist. At day 30, the ChP organoids were characterized using immunocytochemistry and flow cytometry, which revealed the expression of transthyretin (TTR) and chloride intracellular channel 6 (CLIC6) in approximately 72% and 20% of cells, respectively.

Comparing the ChP organoids treated with CHIR (the +CHIR group) to those without CHIR (the -CHIR group), the +CHIR group showed upregulation of six out of ten tested ChP genes, including CLIC6, PLEC, PLTP, DCN, DLK1, and AQP1. In contrast, the +CHIR group exhibited downregulation of TTR, IGFBP7, MSX1, and LUM. Furthermore, when exposed to amyloid beta 42 oligomers, the +CHIR group demonstrated a more sensitive response, as indicated by the upregulation of inflammation-related genes such as TNFα, IL-6, and MMP2/9 compared to the -CHIR group.

The study also investigated the development of EV biogenesis in the ChP organoids over time. The EV biogenesis markers of the ChP organoids showed an increasing trend from day 19 to day 38.

The significance of this study lies in providing a model of the human B-CSF-B and ChP tissue using hiPSC-derived organoids. These organoids can be valuable tools for drug screening and the design of drug delivery systems targeting neurological disorders, including Alzheimer's disease and ischemic stroke. By studying the inflammatory response and EV biogenesis in ChP organoids, researchers can gain insights into the underlying mechanisms of these disorders and potentially develop new therapeutic approaches.