发布: 2020年05月05日第10卷第9期 DOI: 10.21769/BioProtoc.3601 浏览次数: 3317
评审: Giusy TornilloWoojong LeeAnonymous reviewer(s)
Abstract
The search for the origin of the first hematopoietic stem cells (HSCs) in the mouse embryo has been a hot topic in the field of developmental hematopoiesis. Detecting lymphoid potential is one of the supportive evidence to show the definitive hematopoietic activity of HSCs. However, the first B-lymphoid potential in the mouse embryos are reported to be biased to innate-like B-1 cell lineage that can develop from hemogenic endothelial cells (HECs) independently of HSCs. On the other hand, conventional adaptive immune B cells (B-2) cells are considered to be exclusively derived from HSCs. Therefore, segregating B-1 and B-2 progenitor potential is important to understand the developmental process of HSCs that are also produced from HECs through intermediate precursors referred to as pre-HSCs. Both HECs and pre-HSCs show endothelial surface phenotype and require stromal support to detect their hematopoietic activity. The method utilizing stromal cell culture followed by modified semisolid clonal culture enables us to detect the number of colony forming units for B-1/B-2 progenitors originally derived from HECs/pre-HSCs, which will reflect the potential of B-1 biased or multi-lineage repopulating HSCs.
Background
Semisolid clonal culture (methylcellulose colony forming assay) is a traditional method to detect the number of hematopoietic progenitor cells. One colony is considered to be derived from a single progenitor cell (clonal origin). Added cytokines play important roles in the formation of yield colonies. For example, Epo enhances the colony forming unit of erythrocytes (CFU-E) or the burst forming unit of erythrocytes (BFU-E), while G-CSF/GM-CSF will enhance CFU-G (Granurocytes), M (Macrophages) or GM (Granulo-macrophages). SCF stimulate hematopoietic progenitor activity. The formation of B-lymphocyte progenitor colonies from mouse BM requires SCF, IL-7 and Flt3-ligand. Importantly, this assay can detect only the activity of CD45+ (or CD41+ in case of embryo-derived cells) hematopoietic progenitor cells, thus, cannot detect the hematopoietic activity of CD45-CD144+ hemogenic endothelial cells (HECs) that produce various hematopoietic cells in the mouse embryo. The detection of hematopoietic activity of HECs heavily depends on the stromal support or organ culture method. Therefore, it is challenging to determine the number of lymphoid progenitors produced from HECs. Recently, Montecino-Rodriguez et al. (2016) developed a modified semisolid clonal culture using S-17 stromal cells to detect B-1 and B-2 potential of hematopoietic progenitors in embryonic (E) day 10 yolk sac cells and fetal liver cells.
B-1 progenitor cells are mainly detected in the fetal liver and neonatal BM. B-1 cells belong to innate-like B-lymphocytes that produce natural IgM antibodies, while conventional adaptive immune B cells are referred to as B-2 cells. Montecino-Rodriguez et al., identified B-1 cell-specific progenitors in the mouse fetal liver and neonatal BM as lin-IgM-CD19+B220- (CD19 single positive) cells whereas B-2 specific progenitors (Pro-B cell) are lin-IgM-CD19-B220+ (B220 single positive) cells. These two populations quickly become CD19+B220+ double positive in vitro culture, thus, it is difficult to determine if B cells produced from embryonic tissues in the co-culture with stromal cells belong to B-1 or B-2 cells. This modified semisolid clonal culture enables us to detect B-1 and/or B-2 progenitor colonies derived from HECs/pre-HSC by utilizing stromal cells that support B lymphopoiesis (Kobayashi et al., 2019). We used OP9 stromal cells to support B-lymphopoiesis in the semisolid clonal culture, with which we have been successful to induce B lymphocytes from HECs (Yoshimoto et al., 2011; Kobayashi et al., 2019). Since B-2 progenitor colony forming ability seems to be one of the HSC activity, this method may be utilized to evaluate the HSC activity derived from HECs/pre-HSCs in the mouse embryo.
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版权信息
© 2020 The Authors; exclusive licensee Bio-protocol LLC.
如何引用
Kobayashi, M. and Yoshimoto, M. (2020). A Modified Semisolid Clonal Culture for Identification of B-1 and B-2 Progenitor Colony Forming Ability of Mouse Embryonic Hemogenic Endothelial Cells. Bio-protocol 10(9): e3601. DOI: 10.21769/BioProtoc.3601.
分类
发育生物学 > 细胞生长和命运决定 > 分化
干细胞 > 胚胎干细胞 > 基于细胞的分析方法
细胞生物学 > 细胞分离和培养 > 共培养
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