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Epithelial Cells Asymmetrically Release Two Distinct Types of Exosomes with Distinct Protein Compositions; Apical Release Controlled by ALIX, Basolateral Release by Ceramide; Results May Offer Clues to Metastasis
Cells talk to each other to coordinate nutrition, waste removal, energy use, and, in some cases, disease progression. The cells that line the surfaces of organs or specific tissues, called epithelial cells, appear to speak two different languages - one for either side of the cell, according to a new study by researchers based in Japan. The discovery, published online March 16, 2021 in EMBO Reports, could have implications for understanding how cancer spreads and, potentially, for advanced treatments, the team says. The article is titled “ALIX and Ceramide Differentially Control Polarized Small Extracellular Vesicle Release from Epithelial Cells” (https://www.embopress.org/doi/abs/10.15252/embr.202051475). The team, led by Mitsunori Fukuda, PhD, Professor in the Laboratory of Membrane Trafficking Mechanisms, Department of Integrative Life Sciences, Graduate School of Life Sciences at Tohoku University in Japan, examined epithelial cells from a kidney model. The cells release particles called exosomes that carry bits of the cells themselves or information about the cells. The proteins and other genetic information in the exosomes can then influence how other cells behave or function. In health, such an information exchange could help the immune system mount a more tailored approach to an invading pathogen. Some diseased cells, such as cancer, can release exosomes that make healthy cells less resistant to invasion. "Single cells are known to release various kinds of exosomes, but very little is known about the mechanisms by which they are produced and released," Dr. Fukuda said. "In this paper, we found that epithelial cells asymmetrically release two distinct types of exosomes with distinct protein compositions." The researchers developed a purification method to separate out exosomes based on their protein makeup.