The influence of extracellular matrix and prolactin on global gene expression profiles of primary bovine mammary epithelial cellsin vitro

Abstract

An in vitro bovine mammosphere model was characterized for use in lactational biology studies using a functional genomics approach. Primary bovine mammary epithelial cells cultured on a basement membrane, Matrigel, formed three-dimensional alveoli-like structures or mammospheres. Gene expression profiling during mammosphere formation by high-density microarray analysis indicated that mammospheres underwent similar molecular and cellular processes to developing alveoli in the mammary gland. Gene expression profiles indicated that genes involved in milk protein and fat biosynthesis were expressed, however, lactose biosynthesis may have been compromised. Investigation of factors influencing mammosphere formation revealed that extracellular matrix (ECM) was responsible for the initiation of this process and that prolactin (Prl) was necessary for high levels of milk protein expression. CSN3 (encoding kappa-casein) was the most highly expressed casein gene, followed by CSN1S1 (encoding alphaS1-casein) and CSN2 (encoding beta-casein). Eighteen Prl-responsive genes were identified, including CSN1S1, SOCS2 and CSN2, however, expression of CSN3 was not significantly increased by Prl and CSN1S2 was not expressed at detectable levels in mammospheres. A number of novel Prl responsive genes were identified, including ECM components and genes involved in differentiation and apoptosis. This mammosphere model is a useful model system for functional genomics studies of certain aspects of dairy cattle lactation.

Role of extracellular matrix and prolactin in functional differentiation of bovine BME-UV1 mammary epithelial cells

“…4a). Our observations are consistent with the results of other groups working on the 3D culture system of MECs, which showed that the initiation of alveoli-like morphology formation was primarily driven by the ECM, and the acinar structures were formed even in the absence of PRL (Naylor et al 2003, Riley et al 2010). However, Riley and coworkers (2010) have noted in their microarray study of the transcriptional profile of primary bovine MECs cultured on Matrigel, that PRL is necessary for the high expression levels of milk protein genes.…”

“…The most commonly used ECM derivative in this culture system is the reconstituted basement membrane (rBM) derived from the Engelbreth--Holm-Swarm (EHS) mouse sarcoma, commercially available as Matrigel TM . Although many interesting studies with the use of 3D MEC culture have been published, very few describe the regulation of bovine MEC differentiation in the context of their interaction with ECM components (Delabarre et al 1997, Kozłowski et al 2009, Riley et al 2010). The present study shows the rate and mechanisms of the proper development of acinar structures (mammospheres) formed by the bovine mammary epithelial cell line BME-UV1 cultured on Matrigel.…”

In vivo inhibition followed by exogenous supplementation demonstrates galactopoietic effects of prolactin on mammary tissue and milk production in dairy cows

“…Also in primary bovine MEC cultures, PRL has been shown to upregulate the mRNA levels of several caseins (Choi et al, 1988). A high number of other genes are under the control of PRL stimulation, as has been shown in bovine MEC using microarray analyses (Stiening et al, 2008;Riley et al, 2010). In association with its role in MEC differentiation, PRL is also known to promote DNA synthesis and cell proliferation, as has been demonstrated in rabbit and bovine MEC (Suard et al, 1983;Olazabal et al, 2000).…”

Biosynthesis of milk fat, protein, and lactose: roles of transcriptional and posttranscriptional regulation

“…The use of large transcriptomic analysis (i.e., microarray or RNA sequencing) by which to study the adaptation of mammary gland to lactation and/or change in milk production under specific conditions has been carried out in mouse (4,54,122,123,143,189,191,217,236,256), rat (3,47,187), bovine (31,36,56,75,96,144,183,209,218,233,239), sheep (209), goat (71,163,164), human (121,139,147), pig (204), kangaroo (120), and seal (144). It is beyond the scope of the current review to present a thorough discussion of the results from those studies.…”