School of Physiology, Pharmacology and Neuroscience, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, United Kingdom.
School of Physiology, Pharmacology and Neuroscience, Faculty of Life Sciences, University of Bristol, Bristol BS8 1TD, United Kingdom
Immunohorizons. 2020 Aug 7;4(8):464-474. doi: 10.4049/immunohorizons.2000063.
Transgenic zebrafish that express fluorophores under the control of () and () promoters have been widely used to study the dynamics and functions of mononuclear phagocytes (MNPs) in larval zebrafish, unveiling crucial roles for these innate immune cells in many processes, including tissue repair. Adult zebrafish are also being increasingly used as a model organism for such studies because of their regenerative capacity and presence of innate and adaptive immune cells. For example, recent investigations highlight roles of MNPs in the regulation of diverse cellular processes during heart regeneration, including scarring, cardiomyocyte proliferation, and neovascularization. However, transgenic lines that stratify MNP subpopulations (monocytes, macrophages, and dendritic cells) are not yet available, preventing functional analysis of these populations. In an attempt to better segregate cardiac MNPs, we assessed the coexpression of and reporter transgenes in adult zebrafish hearts. Unexpectedly, this also identified a discrete population of lymphoid-like cells, which respond to cardiac cryoinjury in a different temporal pattern to MNPs. lymphoid cells were also abundant in the skin, spleen, and blood, and their frequency was unaffected in the hearts of mutant zebrafish, which display deficiencies in MNP populations. Flow cytometry, imaging, and cytological and gene expression analyses collectively indicate that these cells comprise a mixed population of B cells and NK-like cells. Our study therefore highlights the need to identify novel MNP lineage markers but also suggests undetermined roles of B cells and NK-like cells in cardiac homeostasis and repair in adult zebrafish.
在转基因斑马鱼中，荧光蛋白在 () 和 () 启动子的控制下表达，这些转基因斑马鱼已被广泛用于研究幼鱼单核吞噬细胞（MNPs）的动态和功能，揭示了这些先天免疫细胞在许多过程中的关键作用，包括组织修复。由于成年斑马鱼具有再生能力以及先天免疫细胞和适应性免疫细胞的存在，它们也越来越被用作此类研究的模式生物。例如，最近的研究强调了 MNPs 在心脏再生过程中调节多种细胞过程中的作用，包括瘢痕形成、心肌细胞增殖和新血管生成。然而，目前还没有能够分层 MNPs 亚群（单核细胞、巨噬细胞和树突状细胞）的转基因系，这阻碍了对这些群体的功能分析。为了更好地区分心脏 MNPs，我们评估了成年斑马鱼心脏中 和 报告基因转基因的共表达。出乎意料的是，这也鉴定出了一群离散的 淋巴样细胞，它们对心脏冷冻损伤的反应与 MNPs 不同。 淋巴样细胞在皮肤、脾脏和血液中也很丰富，在 突变体斑马鱼的心脏中其频率不受影响， 突变体斑马鱼的 MNPs 群体存在缺陷。流式细胞术、成像以及细胞学和基因表达分析共同表明，这些细胞是 B 细胞和 NK 样细胞的混合群体。因此，我们的研究不仅强调了需要鉴定新的 MNP 谱系标志物，还表明 B 细胞和 NK 样细胞在成年斑马鱼心脏的稳态和修复中具有未确定的作用。
