Single cell-RNA sequencing for identifying hemocyte subpopulations

In this study, we performed single cell RNA sequencing of isolated hematopoietic tissue (HPT) cells and hemocytes from the crayfish Pacifastacus leniusculus. Thereby, we could identify hitherto undescribed hemocyte types in the circulation, and show that the circulating cells are more diversified than previously recognized. In addition, we discovered cell populations in the HPT with clear precursor characteristics, but also cells involved in iron homeostasis, a previously undiscovered cell type and a finding that may have an impact to understand hematopoietic stem cell regulation in these and other animals. A limitation of the study is that it is done on the transcript-level, as Pacifastacus leniusculus is currently lacking a genomic reference. The sequencing depth is thus divided between a large number of features, compared to what would have been the case at the genome-level. There are, however, efforts currently underway to sequence and annotate the genome, which could potentially be used to re-analyze this data in the future and explore it further. In publications based on this data, the authors must acknowledge SciLifeLab and NGI with the following sentences: “Sequencing was performed by the SNP&SEQ Technology Platform in Uppsala. The facility is part of the National Genomics Infrastructure (NGI) Sweden and Science for Life Laboratory. The SNP&SEQ Platform is also supported by the Swedish Research Council and the Knut and Alice Wallenberg Foundation.”