Single-cell RNA-Seq reveals novel myofibroblast charactering epithelial features in the mammary gland of dairy cows

Our study is the first one to investigate the heterogeneity of bovine mammary gland (MG) and to construct a bovine MG cell atlas by using scRNA-Seq. Our findings provide novel insights into lactation biology of bovine MG. We identified and validated three mature luminal epithelial cells that are involved in the different lactation processes as well as in the immune response. In addition, a novel myofibroblast showing potential differentiation into luminal epithelial cells was identified. The IGF pathway system signal may play an important role in the F13-L5 transition, and the hormone sensing luminal cell (L1), luminal progenitor cells (L2, L3) and immune-sensing luminal cell are correlated with the process. Single-cell RNA sequencing was applied to investigate the transcriptome of 24,472 high-quality MG cells isolated from newborn and adult cows.