Interpretive Summary: Establishment of a bovine rumen epithelial cell line

By: Dr. Emily Taylor

The rumen is essential for digestion and absorption in ruminant animals. Thus, feed ingredients, whether roughage or concentrate, must first be digested by enzymes from microbes in the rumen to produce volatile fatty acids (VFAs). The major VFAs include acetate, propionate, and butyrate, and are the major substrates for energy production, gluconeogenesis, and lipogenesis in ruminants. In addition, the rumen epithelium also serves as a barrier to microbes and other potentially harmful contents in rumen fluid. Diet changes can affect both the structure and function of the epithelial cells. Therefore, the objective of this study was to generate an immortal rumen epithelial cell line that can be used as a convenient model of rumen epithelial cells in vitro. 

Scientists isolated and transduced primary rumen epithelial cells from a steer. These cells were then cloned and used for western blot analysis, reverse transcription, and RNA sequencing and bioinformatics. The expression of the SV40T antigen in two single-cell clones was confirmed using western blot analysis. One clone, named bovine rumen epithelial clone 1 (BREC1), displayed a flat and squamous morphology in culture. Epithelial cell characteristics like keratins, epidermal growth factor receptor, and short-chain fatty acid transporters monocarboxylic acid transporter (MCT) 1 (MCT-1) and MCT-4 were found during RNA sequencing of BREC1 cells. In addition, critical enzymes involved in ketogenesis, which is a unique function of rumen epithelial cells, and expression of genes typical of epithelial cells, encoding tight junctions, desmosomes, anchoring junctions, and polarized plasma membranes were also found. 

The response of BREC1 cells to insulin-like growth factor 1, insulin, and butyrate was similar to primary rumen epithelial cells. Therefore, the authors concluded that BREC1 is a convenient and appropriate model for studying the factors and mechanisms that control proliferation, apoptosis, differentiation, nutrient transport, metabolism, and barrier function in rumen epithelium.

This article is now available in the Journal of Animal Science.