Cross-organ single-cell transcriptome profiling reveals macrophage and dendritic cell heterogeneity in zebrafish

Defining mononuclear phagocyte distribution and behaviour in the zebrafish heart

“…Multiple studies have provided important insight into the ontogeny and maintenance of microglia 65,67,70,79 , but much of this hasn't been investigated in other tissues. Recent studies using single cell sequencing (scRNA-seq) are advancing our understanding of immune cell heterogeneity in the zebrafish heart and other organs [41][42][43]66,70 but much of this has been derived from mpeg1.1 expressing cells and is yet to be translated into new tools to define the distribution of these subpopulations. Our data indicates that using csf1ra and mpeg1.1 transgenic lines it is possible to identify four separate immune cell populations in the homeostatic heart and we have shown that these cells have distinct morphology, distribution, and behaviour in cardiac tissue.…”

“…The absence of the tyrosine kinase receptor MertK, which is involved in phagocytosis 81 , has been described in mammalian classical DCs and in monocytes 18 . DCs have been described in other zebrafish tissues 33 and only very recently in the heart via scRNA-seq 43 . Interestingly, recent scRNA-seq data suggests large numbers of DCs in the heart 43 and CNS 70 of adult zebrafish and that these cells express mpeg1.1 but have reduced levels of csf1ra, supporting our findings.…”

“…DCs have been described in other zebrafish tissues 33 and only very recently in the heart via scRNA-seq 43 . Interestingly, recent scRNA-seq data suggests large numbers of DCs in the heart 43 and CNS 70 of adult zebrafish and that these cells express mpeg1.1 but have reduced levels of csf1ra, supporting our findings. Mammalian DCs are suggested to be smaller than macrophages, mirroring our cytology data, and are most abundant in the atria (specifically the right atrium) rather than the ventricles 82 .…”

“…However, much of the initial characterisation of these markers was performed in larval zebrafish and, although expression in tissue macrophages was confirmed, whether expression extends to monocytes and DCs has not been well defined. Recent technological advancements and accessibility to RNA sequencing technology has facilitated the molecular characterisation of MNPs [40][41][42][43] .…”

Single-cell transcriptional landscape of temporal neutrophil response to burn wound in larval zebrafish

“…Figure 2). Among which, ccl34a.4+ and lgals3bpb+ macrophages were also defined in a recent macrophage scRNA-Seq datasets from adult zebrafish under homeostasis (30). For neutrophils, we performed cross-species label transferring between our zebrafish data and a comprehensive scRNA-Seq mapping of human neutrophils, including four stages: precursors, early immature, immature, and mature neutrophils (6).…”