GSE175640
Single cell next generation sequencing of wild type and Dnmt1 conditional knock in  E18.5 embryonic lung
Background  DNA methylation is an epigenetic mark that restricts chromatin accessibility and serves to modulate temporal and spatial gene expression during organogenesis. Dnmt1 is one of the most studied DNA methyltransferases, and it is primarily involved in preserving the DNA methylation pattern in cells undergoing mitotic division. While the role of Dnmt1 in the embryonic lung endoderm has been revealed, its role in expansion, maintence and differentiation of the embryonic lung mesoderm is mostly unknown. Here, we present the first evidence showing that Dnmt1 is necessary for the proper development of the embryonic lung mesoderm. By selectively deleting Dnmt1 in the embryonic lung mesoderm we found that Dnmt1 is critical for the development of embryonic vasculature and fully commitment of mesoderm towards the lung mesenchymal cell lineages.  Results  Dnmt1 deletion in the embryonic lung mesenchyme at the E7.5 stage led to a lethal phenotype which was characterized by bilateral lung hypoplasia, impaired lung branching morphogenesis, and widespread hemorrhages in the parenchyma. The genesis of the hemorrhages was likely a result of halted development of lung vasculature, specifically the ontogeny of pericytes, which was detected in the mutant lungs. However, despite the severe mesenchyme alteration, differentiation of the lung endoderm appeared normal. When Dnmt1 was deleted at later developmental periods (E13.5), the lung matured normally and mutant pups were viable, although reduced differentiation of Pdgfr-? myofibroblasts and alveolar simplification were observed in all mutant animals as soon as 7 days after birth. Gene expression profiling studies revealed that deletion of Dnmt1 induced the ectopic expression of genes specific for testis, placenta, and ovary, such as Tex10.1, Tex19.1 and Pet2 which suggested a loss of commitment of the lung mesoderm toward the pulmonary cell lineages.   Conclusions  Taken together our findings have shown that dnmt1 expression in the mesenchyme of the developing lung is crucial for restricting the differentiation capacity of the pulmonary mesoderm and, thus, ensuring the adequate differentiation of vasculature cells and myofibroblasts in the fetal and postnatal lung. Overall design: Examination of gene expression changes at the single cell level in wild type and dnmt1-null embryonic murine lungs.