A Single-Cell Transcriptome of Bovine Milk Somatic Cells

Area of Science:

• Animal Science
• Genomics
• Cell Biology

Background:

• High milk yield in dairy cows is crucial for economic viability and is a complex trait influenced by numerous biological factors.
• Lactation in cows provides a valuable model for understanding the cellular mechanisms underlying milk production and mammary gland function.

Purpose of the Study:

• To analyze the bovine milk transcriptome at the single-cell level.
• To identify and characterize diverse cell populations within dairy cow milk.
• To uncover regulatory elements governing mammary gland functions.

Main Methods:

• Single-cell RNA sequencing (scRNA-seq) was performed on milk samples from two Holstein Friesian cows during mid-lactation.
• Milk fat was removed via centrifugation, followed by cell suspension preparation and loading onto the 10× Chromium platform.
• High-throughput sequencing was conducted using the Illumina NovaSeq 6000, with subsequent filtering of cells and genes.

Main Results:

• Successfully reconstructed various cell types present in bovine milk, including milk-producing cells, progenitor cells, and immune cells (macrophages, monocytes, dendritic cells, T cells, B cells, mast cells, neutrophils).
• Generated a comprehensive single-cell transcriptome dataset of bovine milk.
• Identified distinct cellular populations contributing to mammary gland functions.

Conclusions:

• The study provides a valuable single-cell resolution resource for understanding bovine milk composition and mammary gland biology.
• Findings facilitate the identification of regulatory elements controlling key functions such as lactation, immunity, and nutrient synthesis.
• This research enhances our understanding of the cellular basis of high milk yield in dairy cattle.