TGF-beta signalling in bovine mammary gland involution and a comparative assessment of MAC-T and BME-UV1 cells as in vitro models for its study.

Charlotte Alexandra Mitz,Alicia Mercedes Viloria-Petit

doi:10.7717/peerj.6210

Abstract

The goal of the dairy industry is ultimately to increase lactation persistency, which is the length of time during which peak milk yield is sustained. Lactation persistency is determined by the balance of cell apoptosis and cell proliferation; when the balance is skewed toward the latter, this results in greater persistency. Thus, we can potentially increase milk production in dairy cows through manipulating apoptogenic and antiproliferative cellular signaling that occurs in the bovine mammary gland. Transforming growth factor beta 1 (TGFβ1) is an antiproliferative and apoptogenic cytokine that is upregulated during bovine mammary gland involution. Here, we discuss possible applications of TGFβ1 signaling for the purposes of increasing lactation persistency. We also compare the features of mammary alveolar cells expressing SV-40 large T antigen (MAC-T) and bovine mammary epithelial cells-clone UV1 (BME-UV1) cells, two extensively used bovine mammary epithelial cell lines, to assess their appropriateness for the study of TGFβ1 signaling. TGFβ1 induces apoptosis and arrests cell growth in BME-UV1 cells, and this was reported to involve suppression of the somatotropic axis. Conversely, there is no proof that exogenous TGFβ1 induces apoptosis of MAC-T cells. In addition to TGFβ1’s different effects on apoptosis in these cell lines, hormones and growth factors have distinct effects on TGFβ1 secretion and synthesis in MAC-T and BME-UV1 cells as well. MAC-T and BME-UV1 cells may behave differently in response to TGFβ1 due to their contrasting phenotypes; MAC-T cells have a profile indicative of both myoepithelial and luminal populations, while the BME-UV1 cells exclusively contain a luminal-like profile. Depending on the nature of the research question, the use of these cell lines as models to study TGFβ1 signaling should be carefully tailored to the questions asked.

Highlights

The dairy industry could gain significant financial advantage by extending the persistency of lactation (Capuco et al, 2003), which is defined as the number of days in which aHow to cite this article Mitz CA, Viloria-Petit AM. 2019
The authors demonstrated that insulin-like growth factor I (IGF-I) suppresses TGFβ1 expression in bovine mammary epithelial cells-clone UV1 (BME-UV1) cells and MAC-T cells (Zarzynska, Gajewska & Motyl, 2005)
This study revealed that levels of the death receptor ligand Fas ligand were reduced in parallel with increased levels of TGFβ1-induced apoptosis, which supports the findings by Kolek et al (2003) demonstrating that TGFβ1-induced apoptosis in bovine mammary epithelial cells occurs through the intrinsic mitochondrial pathway

Summary

Introduction

The dairy industry could gain significant financial advantage by extending the persistency of lactation (Capuco et al, 2003), which is defined as the number of days in which aHow to cite this article Mitz CA, Viloria-Petit AM. 2019. TGF-beta signalling in bovine mammary gland involution and a comparative assessment of MAC-T and BME-UV1 cells as in vitro models for its study.

Results

Conclusion