Complex mammalian-like haematopoietic system found in a colonial chordate

Article

关键词: STEM-CELLS;    CYTOTOXIC-CELLS;    READ ALIGNMENT;    GENE;    IMMUNE;    ALLORECOGNITION;    IDENTIFICATION;    ZEBRAFISH;    HEMOCYTES;    ENDOSTYLE;   

DOI  :  10.1038/s41586-018-0783-x

来源: SCIE

【 摘 要 】

Haematopoiesis is an essential process that evolved in multicellular animals. At the heart of this process are haematopoietic stem cells (HSCs), which are multipotent and self-renewing, and generate the entire repertoire of blood and immune cells throughout an animal's life(1). Although there have been comprehensive studies on self-renewal, differentiation, physiological regulation and niche occupation in vertebrate HSCs, relatively little is known about the evolutionary origin and niches of these cells. Here we describe the haematopoietic system of Botryllus schlosseri, a colonial tunicate that has a vasculature and circulating blood cells, and interesting stem-cell biology and immunity characteristics(2-8). Self-recognition between genetically compatible B. schlosseri colonies leads to the formation of natural parabionts with shared circulation, whereas incompatible colonies reject each other(3,4,7). Using flow cytometry, whole-transcriptome sequencing of defined cell populations and diverse functional assays, we identify HSCs, progenitors, immune effector cells and an HSC niche, and demonstrate that self-recognition inhibits allospecific cytotoxic reactions. Our results show that HSC and myeloid lineage immune cells emerged in a common ancestor of tunicates and vertebrates, and also suggest that haematopoietic bone marrow and the B. schlosseri endostyle niche evolved from a common origin.

【 授权许可】

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