Different Cre systems induce differential microRNA landscapes and abnormalities in the female reproductive tracts of Dgcr8 conditional knockout mice

Objectives: The female reproductive tract comprises several different cell types. Using three representative Cre systems, we comparatively analysed the phenotypes of Dgcr8 conditional knockout (cKO) mice to understand the function of Dgcr8, involved in canonical microRNA biogenesis, in the female reproductive tract.

Materials and methods: Dgcr8^f/f mice were crossed with Ltf^icre/+ , Amhr2^cre/+ or PR^cre/+ mice to produce mice deficient in Dgcr8 in epithelial (Dgcr8^ed/ed ), mesenchymal (Dgcr8^md/md ) and all the compartments (Dgcr8^td/td ) in the female reproductive tract. Reproductive phenotypes were evaluated in Dgcr8 cKO mice. Uteri and/or oviducts were used for small RNA-seq, mRNA-seq, real-time RT-PCR, and/or morphologic and histological analyses.

Result: Dgcr8^ed/ed mice did not exhibit any distinct defects, whereas Dgcr8^md/md mice showed sub-fertility and oviductal smooth muscle deformities. Dgcr8^td/td mice were infertile due to anovulation and acute inflammation in the female reproductive tract and suffered from an atrophic uterus with myometrial defects. The microRNAs and mRNAs related to immune modulation and/or smooth muscle growth were systemically altered in the Dgcr8^td/td uterus. Expression profiles of dysregulated microRNAs and mRNAs in the Dgcr8^td/td uterus were different from those in other genotypes in a Cre-dependent manner.

Conclusions: Dgcr8 deficiency with different Cre systems induces overlapping but distinct phenotypes as well as the profiles of microRNAs and their target mRNAs in the female reproductive tract, suggesting the importance of selecting the appropriate Cre driver to investigate the genes of interest.