Transcriptomics Comparisons of Mac-T cells Versus Mammary Tissue during Late Pregnancy and Peak Lactation

Abstract

Epithelial cell cultures, including immortalized cells, have been used extensively to help answer basic questions of mammary gland physiology under normal or diseased conditions. The usefulness of using cell culture depends on the degree of identify compared to the in vivo mammary epithelium. Our objective was to compare the transcriptome by means of microarray and qPCR of immortalized bovine mammary epithelial cells (Mac-T) cultivated in plastic (i.e., 2 dimensional system) vs. mammary tissue obtained during late-pregnancy (-30 DIM) and peak lactation (+60 DIM). Functional analysis of microarray data was performed using enrichment analysis tools and the Dynamic Impact Approach (DIA). Overall, between 37% (vs. +60 DIM) and 44% (vs.-30 DIM) of the measured annotated genes were deemed as differentially expressed (DEG) between Mac-T cells and mammary tissue. These data, together with the bioinformatics results of the genes non-differentially expressed, indicated a larger overall similarity between Mac-T cells and lactating than non-lactating mammary tissue. However, Mac-T cells had a lower expression measured by qPCR of genes involved in milk synthesis compared to mammary tissue. The functional analysis of DEG further supported the poor lactation phenotype of Mac-T cells compared with mammary tissue. The bioinformatics analyses of DEG suggested that Mac-T cells cultivated on plastic had greater reliance on glucose, amino acids, and fatty acids for production of energy, greater cell-to-cell interactions, and more prone to react to inflammatory mediators relative to mammary tissue. Despites these differences, data suggest that Mac-T cells might be adequate for studying milk protein regulation. For studies of milk fat regulation Mac-T cells might be not as sensitive as the mammary tissue, particularly for its lower expression of PPARG and lower induction of PPARγ-and LXR-related pathways. Overall, this study revealed a marked difference in the transcriptome signatures between mammary tissue and Mac-T cells cultivated on plastic.

A novel long non‐coding RNA regulates the immune response in MAC‐T cells and contributes to bovine mastitis

“…The MAC‐T cell line is a line of immortalized bovine mammary epithelial cells established by stable transfection with SV‐40 large T‐antigen into primary bovine mammary alveolar cells, and it still maintains classic ‘cobblestone’ morphology and some secretion abilities of mammary epithelial cells (MECs) . Therefore it has been utilized as an easy‐to‐manipulate MEC model, with the properties of facilitating the study of lactation and milk formation and immune functions of MECs . To establish an in vitro cell model of bovine mastitis in this study, heat‐killed bacteria were applied to treat MAC‐T cells, in which tumor necrosis factor‐α (TNF‐α), a well‐known master cytokine governing the early stage of inflammation , was considered as the parameter of immune reaction.…”

Transcriptomic Analysis of Short/Branched-Chain Acyl-Coenzyme a Dehydrogenase Knocked Out bMECs Revealed Its Regulatory Effect on Lipid Metabolism

“…The mammary gland tissue of dairy cows can be used as a bioreactor for most biological research because it has the physiological functions of synthesizing and secreting milk. However, there are some limitations to using this model to research TG synthesis in the mammary gland (26). Culturing in-vitro bovine breast epithelial cells can maintain this ability to synthesize and secrete milk.…”

Heat stress and recovery induce transcriptomic changes in lactogenic bovine mammary epithelial (MAC-T) cells

“…In mammary gland tissues of HS cows, transcriptomic 10 and metabolomic 11 approaches have identified the downregulation of casein genes, amino acid transporter genes, and lipid metabolism pathways, whereas upregulation has been observed in HSPs, immune responses, and inflammatory responses. MAC-T cells, established from immortalized bovine primary mammary epithelial cell (MECs) 12 , can be induced to a lactogenic state to mimic the transcriptomics of the lactating udder 13 . Previous studies using MAC-T cells under HS conditions have primarily focused on their undifferentiated state.…”