Xenogeneic-Free Human Intestinal Organoids for Assessing Intestinal Nutrient Absorption.

Since many nutrients, including the three major ones of glucose, dipeptides, and cholesterol, are mainly absorbed in the small intestine, the assessment of their effects on intestinal tissue is important for the study of food absorption. However, cultured intestinal cell lines, such as Caco-2 cells, or animal models, which differ from normal human physiological conditions, are generally used for the evaluation of intestinal absorption and digestion. Therefore, it is necessary to develop an alternative in vitro method for more accurate analyses. In this study, we demonstrate inhibitory effects on nutrient absorption through nutrient transporters using three-dimensional xenogeneic-free human intestinal organoids (XF-HIOs), with characteristics of the human intestine, as we previously reported. We first show that the organoids absorbed glucose, dipeptide, and cholesterol in a transporter-dependent manner. Next, we examine the inhibitory effect of natural ingredients on the absorption of glucose and cholesterol. We reveal that glucose absorption was suppressed by epicatechin gallate or nobiletin, normally found in green tea catechin or citrus fruits, respectively. In comparison, cholesterol absorption was not inhibited by luteolin and quercetin, contained in some vegetables. Our findings highlight the usefulness of screening for the absorption of functional food substances using XF-HIOs.

Expansion and differentiation of human iPS cells in a three-dimensional culture using hollow fibers and separation of the specific population by magnetic-activated cell sorting.

In order to employ pluripotent stem cells in the field of regenerative medicine, it is necessary to establish a large-scale culture system for cell differentiation. We have developed a novel three-dimensional method for culturing human induced pluripotent stem (iPS) cells, using hollow fibers (HFs). The cells immobilized inside HFs can proliferate and form multicellular aggregates, capable of achieving a high cell density and promoting further spontaneous cell differentiation. We first cultured human iPS cells for 7 days under conditions that maintained their undifferentiated state and then switched the culture conditions to allow spontaneous cell differentiation. In the 7-day undifferentiated culture, a high cell density of approximately 10-fold that of the initial seeding density was achieved. The upregulation of gene markers for differentiation such as CXCR4 or SOX17 was observed in the culture of differentiated cells. Expression of the lineage-specific cell-surface marker CXCR4 was about 30% at day 5 in the differentiation culture, which was 2-fold higher than that in the traditional monolayer culture. After HF culture, we obtained the CXCR4-positive cell population and performed monolayer culture for further differentiation of the hepatic lineage. In the CXCR4-positive cell population, the expression levels of a few liver-specific gene markers tended to increase. However, there were no significant differences between the separation and non-separation groups, which indicates the need for refinement of the cell separation process and cell maturation procedure in future studies. In conclusion, the HF culture method has potential for achieving the large-scale culturing and spontaneous differentiation of human iPS cells.

Prevention of copper-induced cell death by GC-rich DNA oligomers in murine macrophage-like RAW264.7 cells.

Impact of redox active transition metals on activation of cell death signaling in plant cells have been documented to date. We have recently reported that GC-rich DNA oligomers with high affinity for binding of copper and catalytic activity for removal of ROS as novel plant cell-protecting agents. Here, we show that similar DNA oligomers protect the mouse macrophage-like RAW264.7 cells from copper-induced cell death, suggesting that the phenomenon firstly observed in plant model can be expanded to a wider range of cells and/or organisms including mammalian cells.