Single-cell transcriptome analysis reveals abnormal angiogenesis and placentation by loss of imprinted glutaminyl-peptide cyclotransferase.

Abstract

Imprinted genes play a key role in regulating mammalian placental and embryonic development. Here, we generated glutaminyl-peptide cyclotransferase-knockout (<i>Qpct</i>^-/-) mice utilizing the clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) platform and identified <i>Qpct</i> as a novel anti-angiogenic factor in regulating mouse placentation. Compared with <i>Qpct</i>^+/+ mice, placentae and embryos (<i>Qpct</i>^-/+ and <i>Qpct</i>^-/-) showed significant overgrowth at embryonic Day 12.5 (E12.5), E15.5, and E18.5. Using single-cell transcriptome analysis of 32 309 cells from <i>Qpct</i>^+/+ and <i>Qpct</i>^-/- mouse placentae, we identified 13 cell clusters via single-nucleus RNA sequencing (snRNA-seq) (8880 <i>Qpct</i>^+/+ and 13 577 <i>Qpct</i>^-/- cells) and 20 cell clusters via single-cell RNA sequencing (scRNA-seq) (6567 <i>Qpct</i>^+/+ and 3285 <i>Qpct</i>^-/- cells). Furthermore, we observed a global up-regulation of pro-angiogenic genes in the <i>Qpct</i>^-/- background. Immunohistochemistry assays revealed a notable increase in the number of blood vessels in the decidual and labyrinthine layers of E15.5 <i>Qpct</i>^-/+ and <i>Qpct</i>^-/- mice. Moreover, the elevation of multiple pairs of ligand-receptor interactions was observed in decidual cells, endothelial cells, and macrophages, promoting angiogenesis and inflammatory response. Our findings indicate that loss of maternal <i>Qpct</i> leads to altered phenotypic characteristics of placentae and embryos and promotes angiogenesis in murine placentae.