Embryonic mesothelial-derived hepatic lineage of quiescent and heterogenous scar-orchestrating cells defined but suppressed by WT1

Activated hepatic stellate cells (aHSCs) orchestrate scarring during liver injury, with putative quiescent precursor mesodermal derivation. Here we use lineage-tracing from development, through adult homoeostasis, to fibrosis, to define morphologically and transcriptionally discreet subpopulations of aHSCs by expression of WT1, a transcription factor controlling morphological transitions in organogenesis and adult homoeostasis. Two distinct populations of aHSCs express WT1 after injury, and both re-engage a transcriptional signature reflecting embryonic mesothelial origin of their discreet quiescent adult precursor. WT1-deletion enhances fibrogenesis after injury, through upregulated Wnt-signalling and modulation of genes central to matrix persistence in aHSCs, and augmentation of myofibroblastic transition. The mesothelial-derived lineage demonstrates punctuated phenotypic plasticity through bidirectional mesothelial-mesenchymal transitions. Our findings demonstrate functional heterogeneity of adult scar-orchestrating cells that can be whole-life traced back through specific quiescent adult precursors to differential origin in development, and define WT1 as a paradoxical regulator of aHSCs induced by injury but suppressing scarring.


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For mechanistic animal studies where fibrosis as the readout was assessed a power calculation was performed per Home Office project licence. For in vitro and transcriptomic studies, experiments were undertaken on a minimum of three independent replicates.
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The animals used for injury modelling in this study were all on a C57Bl/6 background aged within 8-12 weeks old and >20g body weight at the start of the experiments. Male mice were used for in vivo studies; male and female mice were used for in vitro studies. WT1GFP/+ knockin reporter mice were originally provided by H. Sugiyama (Osaka University School of Medicine, Japan). WT1CreERT2/+;Ai14 mice for lineage tracing were created by crossing knockin mice expressing tamoxifen-inducible Cre recombinase at the WT1 promoter locus (WT1CreERT2/+) with the Ai14 Cre reporter. The WT1-conditional background (WT1fl/ fl) was used to create lines allowing WT1 deletion. The constitutive PDGFRCre line was obtained from N. Henderson (University of Edinburgh).

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Primary hepatic stellate cells from injured or uninjured animals were obtained by density centrifugation and examined immediately after isolation of after culture on plastic.
BD FACS Aria II BD FACSDiva was used for data collection. FlowJo was used for data analysis.

October 2018
Cell population abundance